20031207 Ver 1_COMPLETE FILE_20070831

OF W ATF9 Michael F. Easley, Gove
O? PG William G. Ross Jr., Secre
North Carolina Department of Environment and Natural Resou
co
r
>_ y Alan W. Klimek, P.E.,Dire
D Division of WaterQu
Coleen H. Sullins, Deputy Dire
Division of Water Qui
November 4, 2004
NCDENR Ecosystem Enhancement Program
c/o Kristin Miguez
1652 Mail Service Center
Raleigh, NC 270699-1?tUBJECT:
NOV 16 2004
D,DS oS opt TE t
Y 'Elw ROO
Dear Ms. Miguez:
Approval of 401 Water Quality Certification
and Additional Conditions
Hewlett's Creels Stream Restoration Project
DWQ Project # 031207
New Hanover County
You have our approval, in accordance with the attached conditions (WQC #3399), to do the following
activity at Pine Valley Country Club located at 500 Pine Valley Drive in Wilmington, New Hanover
County. This approval allows you to:
1. Impact 3527 linear feet of Hewlett's Creek for the purpose of restoring the historic stream
functions to the system, modifying the adjacent floodplain so that it becomes accessible to the
stream, and establishing buffers to protect water quality and enhance wildlife.
This approval is only valid for the purpose and design that you described in you Pre-Construction
Notification (PCN) application received by the Division of Water Quality (DWQ) on September 26, 2003,
and additional information received on September 7, 2004. After reviewing your application, we have
determined that General Water Quality Certification Number 3399 covers this activity,-This Certification
can also be found on line at: http://h2o.enr.state.nc.us/ncwetiands/certs.html. html. This Certification (#3399)
allows you to use your 404 Permit when the Corps of Engineers issues it. Please keep in mind that there
may be additional Federal, State or Local regulations applicable to your project, such as (but not limited
to) Sediment and Erosion Control, Non-Discharge and Water Supply Watershed regulations, NPDES
Stormwater and Coastal Stormwater. In addition, this approval will expire when the accompanying
404 Permit expires unless otherwise specified in the General Certification.
Please be aware that if you change or modify your project, you must notify the Division
(DWQ) in writing and you may be required to send us a new application for a new certification. If the
property is sold, the new owner must be given a copy of the Certification and approval letter and is
thereby responsible for complying with all conditions. If total wetland fills for this project (now or in the
future) exceed one acre, compensatory mitigation may be required as described in 15A NCAC 2H .0506
(h). For this approval to be valid, you must follow the conditions listed in the attached certification
and the additional conditions listed on the following page.
N. C. Division of Water Quality 127 Cardinal Drive Extension [phone] Customer Service
Wilmington Regional Office Wilmington, NC 28405 [phone] Fax [phone] One
An Equal Opportunity/Affirmative Action Employer - 50% Recycled/10% Post Consumer Paper Nor Lhuarollna
Naturally
NCDENR Ecosystem Enhancement Program
DWQ Project No. 031207
November 4, 2004
1. Impacts Approved
The following impacts are hereby approved as long as all of the other specific and general
conditions are met. No other impacts are approved including incidental impacts:
Amount Approved
(Units) Plan Location or Reference
Stream 3527 feet Figure 4, 59 6
404/CAMA Wetlands N/A (acres)
Waters N/A (acres)
Buffers N/A (square ft.
2. Erosion and sediment control practices must be in full compliance with all specifications
governing the proper design, installation and operation and maintenance of such Best
Management Practices in order to protect surface waters standards:
a. The erosion and sediment control measures for the project must be designed, installed,
operated, and maintained in accordance with the most recent version of the North Carolina
Sediment and Erosion Control Planning and Design Manual.
b. The design, installation, operation, and maintenance of the sediment and erosion control
measures must be such that they equal, or exceed, the requirements specified in the most
recent version of the North Carolina Sediment and Erosion Control Manual. The devices
shall be maintained on all construction sites, borrow sites, and waste pile (spoil) projects,
including contractor-owned or leased borrow pits associated with the project.
3. No land disturbance or fill of any kind shall occur in wetlands or waters beyond the footprint of
the impacts depicted in the Pre-construction Notice Application. All construction activities,
including the design, installation, operation, and maintenance of sediment and erosion control
Best Management Practices, shall be performed so that no violations of state water quality
standards, statutes, or rules occur.
4. Upon completion of all work approved within the 401 Water Quality Certification or applicable
Buffer Rules, and any subsequent modifications, the applicant is required to return the attached
certificate of completion and a sealed copy of the as-built plans to this office and a copy to the
401/Wetlands Unit, North Carolina Division of Water Quality, 1650 Mail Service Center,
Raleigh, NC, 27699-1650.
Please notify the Wilmington Regional Office at [phone]) if any problem arises during the
construction of the project that may affect water quality.
Please read the attached conditions. If you do not accept any of the conditions of this certification,
you may ask for an adjudicatory hearing. You must act within 60 days of the date that you receive this
letter. To ask for a hearing, send a written petition conforming to Chapter 150B of the North Carolina
General Statutes to the Office of Administrative Hearings, 6714 Mail Service Center, Raleigh, N.C.
27699-6714. This certification and its conditions are final and binding unless you ask for a hearing.
NCDENR Ecosystem Enhancement Program
DWQ Project No. 031207
November 4, 2004
This letter completes the review of the DWQ Permit # 031207. If you have any questions, please
telephone Noelle Lutheran at 910-395-3900.
Sincerely,

Alan W. Klimek, P.E.
t Director, Division of Water Quality
Attachments: GC # 3399
Certificate of Completion
3
cc: Jennifer Frye - Corps of Engineers Wilmington Field Office
Cyndi Karoly - 401/Wetland Unit, Central Office
Noelle Lutheran - WiRO
WQC #3399
STREAM RESTORATION, ENHANCEMENT AND STABILIZATION AND WETLAND AND
RIPARIAN RESTORATION AND CREATION ACTIVITIES CERTIFICATION
GENERAL CERTIFICATION FOR STREAM RESTORATION, ENHANCEMENT AND
STABILIZATION PROJECTS AND WETLAND AND RIPARIAN RESTORATION AND
CREATION ACTIVITIES INCLUDING THOSE ELIGIBLE FOR CORPS OF ENGINEERS
NATIONWIDE PERMIT NUMBERS 13 (BANK STABILIZATION) AND 27 (WETLAND AND
RIPARIAN RESTORATION AND CREATION) AND REGIONAL PERMIT 197800080
(CONSTRUCTION AND MAINTENANCE OF BULKHEADS)
This General Certification is issued in conformity with the requirements of Section 401, Public
Laws 92-500 and 95-217 of the United States and subject to the North Carolina Division of Water
Quality Regulations in 15A NCAC 2H .0500 and 15A NCAC 2B .0200 for the discharge of fill
material to waters as described in 33 CFR 330 Appendix A (B) (13) and (27) of the Corps of
Engineers regulations (i.e. Nationwide Permit Numbers 13 and 27) and Regional Permit
197800080. The category of activities shall include stream bank stabilization or stream
restoration activity as long as impacts to waters or significant wetlands are minimized. This
Certification replaces Water Quality Certification (WQC) Number 1663 issued on September 8,
1983; WQC No. 1272 issued November 10, 1978; WQC No. 2665 issued on 21 January 1992;
WQC No. 2102 issued on February 11, 1997, WQC Nos. 3256, 3257 and 3258 issued on
November 22, 1999 and WQC No. 3353 issued on March 18, 2002. This WQC is rescinded
when the Corps of Engineers reauthorize Nationwide Permits 13 or 27 or Regional Permit
197800080 or when deemed appropriate by the Director of the Division of Water Quality (DWQ).
The State of North Carolina certifies that the specified category of activity will not violate
applicable portions of Sections 301, 302, 303, 306 and 307 of the Public Laws 92-500 and 95-217
if conducted in accordance with the conditions set forth.
Conditions of Certification:
Wetland and/or riparian area restoration and creation projects which are for
compensatory mitigation or compensatory mitigation credit (and not including
projects that only involve stream restoration or enhancement work described in
condition nos. 2 and 3 below) that are proposed under this General Certification
require written application to and approval from the Division of Water Quality. All
applications for written DWQ approval will be reviewed and a response will be
prepared within 30 days of stamped receipt of the application in the Division of
Water Quality's Central Office in Raleigh. This 30-day period does not include time
spent by the application or DWQ's response within US Postal Service or North
Carolina's Mail Service Center mail systems;
Wetland and riparian area restoration and creation projects (not including projects
that involve work in or impacts to streams) which are not for compensatory
mitigation or compensatory mitigation credit proposed under this General
Certification do not require written application to and approval from the Division of
Water Quality. In these cases, the applicant is required to notify the Division in
writing with three copies of project specifications before the impact occurs. If the
Division determines that the project would not result in an ecologically viable wetland
and riparian area, then the Division shall prepare a response to notify the applicant
in writing within 30 days of DWQ's receipt of the notification. In such cases, the
applicant will be required to submit a formal application and pay of the appropriate
fee, and DWQ will be required to process the application through normal
procedures;
WQC #3399
2. Proposed stream restoration projects (as defined and limited below), that do not
disturb wetlands and that are not being conducted for compensatory mitigation or
compensatory mitigation credit do not require written application to and approval
from the Division of Water Quality, and, therefore, do not require payment of an
application fee to the Division of Water Quality.
Stream restoration is defined as the process of converting an unstable, altered or
degraded stream corridor, including adjacent riparian zone and floodprone areas to
its natural or referenced, stable conditions considering recent and future watershed
conditions. This biological and chemical integrity, including transport of water and
sediment is produced by the stream's watershed in order to achieve dynamic
equilibrium. The applicant is required to notify the Division in writing with three
copies of detailed restoration plans and specifications before the impact occurs. If
the Division determines that the project does not meet the above definition of stream
restoration, then the Division shall notify the applicant in writing within 30 days of
receipt of the application. In such cases, the applicant will be required to submit a
formal application and pay of the appropriate fee, and DWQ will be required to
process the application through normal procedures;
3. Stream enhancement projects (as defined and limited below), that do not disturb
wetlands and that are not being conducted for compensatory mitigation or
compensatory mitigation credit and do not include any stream channel relocation, do
not require written application to and approval from the Division of Water Quality,
and, therefore, do not require payment of an application fee to the Division of Water
Quality.
Stream enhancement is defined as the process of implementing stream
rehabilitation practices in order to improve water quality and/or ecological function.
These practices must only be conducted on streams that are not experiencing
severe aggradation or erosion. Stream enhancement does not include the relocation
of the stream channel. Stream enhancement bank stabilization techniques include
the use of woody vegetation as the primary means of long term stability, and "soft"
techniques such as root wads that encourage the establishment of dense woody
vegetation. Stream enhancement techniques do not typically include the use of
stream bank or bed hardening techniques such as rip-rap or other rock, gabion,
block or concrete structures. However, enhancement activities may also include the
placement of in stream habitat or grade control structures such as cross vanes, j-
hook vanes, and wing deflectors that do not affect the overall dimension, pattern, or
profile of a stable stream.
The applicant is required to notify the Division in writing with three copies of detailed
enhancement plans and specifications before the impact occurs if the stream
enhancement project disturbs greater than 500 feet of stream bank or if the project
proposes the use of in stream structures. If the Division determines that the project
does not meet the above definition of stream enhancement, then the Division shall
notify the applicant in writing with an explanation within 30 days of receipt of the
notification to require application and payment of the appropriate fee;
4. Stream stabilization projects that include the use of any structure or fill in the existing
stream bed or disturb greater that 500 feet of stream bank that are proposed under
this General Certification require written application to and approval from the
Division of Water Quality.
Stream stabilization is defined as the in-place stabilization of an eroding stream
bank using measures that consist primarily of "hard" engineering, such as but not
WQC #3399
limited to concrete lining, rip rap or other rock, and gabicns. The use of "hard"
engineering will not be considered as stream restoration or enhancement:
5. Impacts to any stream length in the Neuse, Tar-Pamlico or Randleman River Basins
(or any other major river basins with Riparian Area Protection Rules [Buffer Rules] in
effect at the time of application) requires written concurrence for this Certification
from DWQ in accordance with 15A NCAC 26.0200. Activities listed as "exempt"
from these rules do not need to apply for written concurrence under this
Certification. New development activities located in the protected 50-foot wide
riparian areas (whether jurisdictional wetlands or not) within the Neuse and Tar-
Pamlico River Basins shall be limited to "uses" identified within and constructed in
accordance with 15A NCAC 2B.0200. All new development shall be located,
designed, constructed, and maintained to have minimal disturbance to protect water
quality to the maximum extent practicable through the use of best management
practices;
6. In order for the above conditions to be valid, any plans not requiring written
concurrence to use this Certification must be built according to the plans provided to
the Division of Water Quality. If written concurrence is required, then the project
must be built and maintained according to the plans approved by the written
concurrence and Certification from the Division of Water Quality;
7. Appropriate sediment and erosion control practices which equal or exceed those
outlined in the most recent version of the "North Carolina Erosion and Sediment
Control Planning and Design Manual" or "North Carolina Surface Mining Manual"
whichever is more appropriate (available from the Division of Land Resources at the
DENR Regional and Central Offices) shall be designed, installed and maintained
properly to assure compliance with the appropriate turbidity water quality standard
(50 NTUs in streams and rivers not designated as trout waters by DWQ; 25 NTUs in
all saltwater classes and all lakes and reservoirs; 10 NTUs in DWQ-classified trout
waters);
8. All sediment and erosion control measures placed in wetlands or waters shall be
removed and the original grade restored after the Division of Land Resources or
delegated program has released the project;
9. Any rip-rap shall be of such a size and density so as not to be able to be carried off
by wave or current action and consist of clean rock or masonry material free of
debris or toxic pollutants. Rip-rap shall not be installed in the streambed except in
specific areas required for velocity control and approved by the Division of Land
Resources and Water Quality. However rock vanes, wing deflectors, and similar
structures for grade control and bank protection are acceptable;
10. Measures shall be taken to prevent live or fresh concrete from coming into contact
with freshwaters of the state until the concrete has hardened;
11. If an environmental document is required, this Certification is not valid until a Finding
of No Significant Impact or Record of Decision is issued by the State
Clearinghouse;
12. Additional site-specific conditions may be added to projects which require written
concurrence under this Certification in order to ensure compliance with all applicable
water quality and effluent standards;
WQC #3399
13. Concurrence from DWQ that this Certification applies to an individual project shall
expire three years from the date of the cover letter from DWQ or the notification sent
to DWQ.
Non-compliance with or violation of the conditions herein set forth by a specific project shall
result in revocation of this Certification for the project and may also result in criminal and/or civil
penalties.
The Director of the North Carolina Division of Water Quality may require submission of a
formal application for individual Certification for any project in this category of activity that requires
written concurrence under this certification, if it is determined that the project is likely to have a
significant adverse.effect upon water quality or degrade the waters so that existing uses of the
wetland or downstream waters are precluded.
Public hearings may be held for specific applications or group of applications prior to a
Certification decision if deemed in the public's best interest by the Director of the North Carolina
Division of Water Quality.
Effective date: March 2003
DIVISION OF WATER QUALITY
By
Alan W. Klimek, P.E.
Director
WQC # 3399
DWQ Project No.:
Applicant:
Project Name:
Date of Issuance of 401 Water Quality Certification:
County:
Certificate of Completion
Upon completion of all work approved within the 401 Water Quality Certification or applicable Buffer Rules, and any subsequent
modifications, the applicant is required to return this certificate to the 401/Wetlands Unit, North Carolina Division of Water
Quality, 1621 Mail Service Center, Raleigh, NC, 27699-1621. This form may be returned to DWQ by the applicant, the
applicant's authorized agent, or the project engineer. It is not necessary to send certificates from all of these.
Applicant's Certification
1, , hereby state that, to the best of my abilities, due care and diligence was .used in
the observation of the construction such that the construction was observed to be built within substantial compliance and intent of
the 401 Water Quality Certification and Buffer Rules, the approved plans and specifications, and other supporting materials.
Signature: Date:
Agent's Certification
I, , hereby state that, to the best of my abilities, due care and diligence was used in
the observation of the construction such that the construction was observed to be built within substantial compliance and intent of
the 401 Water Quality Certification and Buffer Rules, the approved plans and specifications, and other supporting materials.
Signature: Date:
Engineer's Certification
Partial Final
I, , as a duly registered Professional Engineer in the State of North Carolina,
having been authorized to observe (periodically, weekly, full time) the construction of the project,for the Permittee hereby state
that, to the best of my abilities, due care and diligence was used in the observation of the construction such that the construction
was observed to be built within substantial compliance and intent of the 401 Water Quality Certification and Buffer Rules, the
approved plans and specifications, and other supporting materials.
Signature
Date
Mail to: 401 Wetlands Contact
NC Dept. of Environment and Natural Resources
127 Cardnal Drive Ext.
Wilmington, NC 28405-2004
Registration No.
MEMORANDUM
TO: John Dorney Regional Contact:
Non-Discharge Branch WQ Supervisor:
Date:
SUBJECT: WETLAND STAFF REPORT AND RECOMMENDATIONS
Facility Name Hewlett's Creek Stream Restoration
Project Number 03 1207
Recvd From WRY
Received Date 9/26/03
Recvd By Region
Project Type stream restoration project
County New Hanover
County2
Region Wilmington
Certificates Stream
Permit Wetland Wetland Wetland Stream Class Acres Feet
Type Type Impact Score Index Prim. Supp. Basin Req. Req.
27 Stream P-7-@ N 18 87-26 SA HQw 30,624. F-x3,527.00
Mitigation Wetland
MitigationType Type Acres Feet
Stream restoration Stream rF 3,527.00
?I
Is Wetland Rating Sheet Attached? Q Y O N Did you request more info? Q Y O N
Have Project Changes/Conditions Been Discussed With Applicant? Q Y O N
Is Mitigation required? Q Y O N
Recommendation: Q Issue O Issue/Cond O Deny
Provided by Region: Latitude (ddmmss) Longitude (ddmmss)
Comments:
On Friday- November 14, Mac Haupt with WRP/EEP notified this office that this project has been
officially dropped and a permit is no longer being requested, NML
A new PCN was submitted to Raleigh on September 7, 2004sequesting approval to move forward
with the original stream restoration proposal_ This office has no objection to the project as proposed
provided that all of the conditions of General Water Quality Certification #3399 and additional
conditions listed in the written 401 WOO are met.
The 401 WQC was issued on 11/4/04. NML
cc: Regional Office
Central Office Page Number 1
Triage Check List
Date: ?Project Name: ue""Jlew C?,k 1?100
DWQ#: bl,
County: AgV70y e f
To: ? ARO Kevin Barnett ? WaRO
? FRO Ken Averitte ff WiRO
? MRO Alan Johnson ?' WSRO
? RRO Mike Horan
Tom Steffens
Noelle Lutheran
Daryl Lamb
From: ?Q 6chi2,IE10?a0 Telephone : (919)

The file attached is being forwarded to "" ur for your evaluation.
Please call if you need assistance.
? Stream length impacted
? Stream determination
? Wetland determination and distance to blue-line surface waters on USFW topo maps
? Minimization/avoidance issues
? Buffer Rules (Meuse, Tar-Pamlico, Catawba, Randleman)
? Pond fill -
? Mitigation Ratios
? Ditching
? Are the stream and or wetland mitigation sites available and viable?
? Check drawings for accuracy
? Is the application consistent with pre-application meetings?
? Cumulative impact concern
Comments: k S&_o d

6`e /- 7
401- G'Fo55
/ e i,? iIa ?t a? boa /01-5, 76T
`ill Y

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_:__-?1.>_1 21 x J?lr
PROGRAM
September 3, 2004
Ms. Cyndi Karoly WETONDS / 401 GROUP
Division of Water Quality
Wetlands/401 Certification Unit SEP 0
1650 Mail Service Center 7 2004
Raleigh, NC 27699-1650 WATER QUALITY SECTION
Re: Hewlett's Creek Stream Restoration Project, Pine Valley Country Club
DWQ Project No. 03-12W
Dear Ms. Karoly:
Please accept the enclosed PCN forms and restoration plans in support of the above referenced
project. The Wetlands Restoration Program (now the Ecosystem Enhancement Program)
originally submitted this information back in September of 2003. However, in November of
2003, our program withdrew our application. At the time, our program had reached a stalemate
with the landowner, and it was assumed that the project would not continue. Over the past
months, the City of Wilmington has worked with EEP to resurrect the project, and more recently
entered into an agreement with the EEP to continue managing the design and construction of the
project. It is anticipated that construction of this project will begin later this fall.
Please contact the project manager, Kristin Miguez, at [phone] if you have any questions
or require additional information at this time.
S
esign and Construction Supervisor
cc: Project File
Prot-" oar State,
?An
NCDENR
North Carolina Ecosystem Enhancement Program, 1652 Mail Service Center, Raleigh, NC 27699-1652 / 919-715-0476 / www.nceep.net
R"-Or' ... L ... Protect' oar ft-a& ®??
NCDENR
North Carolina Ecosystem Enhancement Program, 1652 Mail Service Center, Raleigh, NC 27699-1652 / 919-715-0476 / www.nceep.net
.
Office Use Only: Form Version May 2002
USACE Action ID No. 200301341 DWQ No. 03-140-7-- 12 o `7
(If any particular item is not applicable to this project, please enter "Not Applicable" or "N/A".)
1. Processing
1. Check all of the approval(s) requested for this project:
® Section 404 Permit ? Riparian or Watershed Buffer Rules
? Section 10 Permit ? Isolated Wetland Permit from DWQ
® 401 Water Quality Certification
2. Nationwide, Regional or General Permit Number(s) Requested: Nationwide 27 [Permit
issued October 30, 2003 (Action ID# 200301341)]
3. If this notification is solely a courtesy copy because written approval for the 401 Certification
is not required, check here: ?
4. If payment into the North Carolina Wetlands Restoration Program (NCWRP) is proposed for
mitigation of impacts (verify availability with NCWRP prior to submittal of PCN), complete
section VIII and check here: ?
If your project is located in any of North Carolina's twenty coastal counties (listed on page
4), and the project is within a North Carolina Division of Coastal Management Area of
Environmental Concern (see the top of page 2 for further details), check here: ?
II. Applicant Information
1. Owner/Applicant Information
Name: NC DENR Ecosystem Enhancement Program
Mailing Address: 1652 Mail Service Center, Raleigh, NC 27699-1652
Telephone Number: 919-715-0476 Fax Number: 919-715-2001
E-mail Address: kristin.miguez(a)ncmail.net
2. Agent/Consultant Information (A signed and dated copy of the Agent Authorization letter
must be attached if the Agent has signatory authority for the owner/applicant.)
Name: N/A
Company Affiliation: te,
Mailing Address: r /401 GRo Up
Telephone Number:
E-mail Address:
Fax Number:
Page 5 of 13

III. Project Information
Attach a vicinity map clearly showing the location of the property with respect to local
landmarks such as towns, rivers, and roads. Also provide a detailed site plan showing property
boundaries and development plans in relation to surrounding properties. Both the vicinity map
and site plan must include a scale and north arrow. The specific footprints of all buildings,
impervious surfaces, or other facilities must be included. If possible, the maps and plans should
include the appropriate USGS Topographic Quad Map and NRCS Soil Survey with the property
boundaries outlined. Plan drawings, or other maps may be included at the applicant's discretion,
so long as the property is clearly defined. For administrative and distribution purposes, the
USACE requires information to be submitted on sheets no larger than 11 by 17-inch format;
however, DWQ may accept paperwork of any size. DWQ prefers full-size construction
drawings rather than a sequential sheet version of the full-size plans. If full-size plans are
reduced to a small scale such that the final version is illegible, the applicant will be informed that
the project has been placed on hold until decipherable maps are provided.
1. Name of project: Hewlett's Creek Stream Restoration, Pine Valley Country Club
2. T.I.P. Project Number or State Project Number (NCDOT Only):
3. Property Identification Number (Tax PIN):
4. Location
County: New Hanover Nearest Town: Wilmington
Subdivision name (include phase/lot number):
Directions to site (include road numbers, landmarks, etc.): I-40 East to NC 132, right on
Pine Valley Drive, follow to Count Club 500 Pine Valley Drive)
5. Site coordinates, if available (UTM or Lat/Long):
(Note - If project is linear, such as a road or utility line, attach a sheet that separately lists the
coordinates for each crossing of a distinct waterbody.)
6. Property size (acres): 9 acres
7. Nearest body of water (stream/river/sound/ocean/lake):Hewlett's Creek, Greenville Sound,
Atlantic Ocean
8. River Basin: Cape Fear
(Note - this must be one of North Carolina's seventeen designated major river basins. The
River Basin map is available at http:/ih2o.enr.state.nc.us/admin/maps/.)
9. Describe the existing conditions on the site and general land use in the vicinity of the project
at the time of this application: See attached restoration plan - current land uses includes a
golf course and adjacent residential development
Page 6 of 13
10. Describe the overall project in detail, including the type of equipment to be used:
Proiect includes the restoration of approximately 3500 linear feet of channelized, degraded
stream and associated stream buffer. See attached restoration plan.
11. Explain the purpose of the proposed work: Stream Restoration - Restore historic stream
functions to the system, modify the adjacent floodplain so that it becomes accessible to the
stream, establish buffers to protect water quality and enhance wildlife.
IV. Prior Project History
If jurisdictional determinations and/or permits have been requested and/or obtained for this
project (including all prior phases of the same subdivision) in the past, please explain. Include
the USACE Action ID Number, DWQ Project Number, application date, and date permits and
certifications were issued or withdrawn. Provide photocopies of previously issued permits,
certifications or other useful information. Describe previously approved wetland, stream and
buffer impacts, along with associated mitigation (where applicable). If this is a NCDOT project,
list and describe permits issued for prior segments of the same T.I.P. project, along with
construction schedules.
DWQ Project Number 03-1207, Nationwide 27 [Permit issued October 30, 2003 (Action ID#
200301341)1
V. Future Project Plans
Are any future permit requests anticipated for this project? If so, describe the anticipated work,
and provide justification for the exclusion of this work from the current application.
No
VI. Proposed Impacts to Waters of the United States/Waters of the State
It is the applicant's (or agent's) responsibility to determine, delineate and map all impacts to
wetlands, open water, and stream channels associated with the project. The applicant must also
provide justification for these impacts in Section VII below. All proposed impacts, permanent
and temporary, must be listed herein, and must be clearly identifiable on an accompanying site
plan. All wetlands and waters, and all streams (intermittent and perennial) must be shown on a
Page 7 of 13
delineation map, whether or not impacts are proposed to these systems. Wetland and stream
evaluation and delineation forms should be included as appropriate. Photographs may be
included at the applicant's discretion. If this proposed impact is strictly for wetland or stream
mitigation, list and describe the impact in Section VIII below. If additional space is needed for
listing or description, please attach a separate sheet.
1. Provide a written description of the proposed impacts:
Stream imlacts will be those associated with restoration and enhancement practices as described
in the attached plan.
2. Individually list wetland impacts below:
Wetland Impact
Site Number
indicate on ma
Type of Impact* Area of
Impact
acres Located within
100-year Floodplain**
es/no Distance to
Nearest Stream
linear feet
Type of Wetland***

* List each impact separately and identify temporary impacts. Impacts include, but are not limited to: mechanized clearing, grading, fill,
excavation, flooding, ditching/drainage, etc. For dams, separately list impacts due to both structure and flooding.
** 100-Year floodplains are identified through the Federal Emergency Management Agency's (FEMA) Flood Insurance Rate Maps
(FIRM), or FEMA-approved local floodplain maps. Maps are available through the FEMA Map Service Center at 1-800-358-9616, or
online at http://www.feina.gnv.
*** List a wetland type that best describes wetland to be impacted (e.g., freshwater/saltwater marsh, forested wetland, beaver pond,
Carolina Bay, bog, etc.) Indicate if wetland is isolated (determination of isolation to be made by USACE only).
List the total acreage (estimated) of all existing wetlands on the property: 1 acre
Total area of wetland impact proposed: 0
3. Individually list all intermittent and perennial stream impacts below: See Restoration Plan
Stream Impact
Site Number
indicate on ma
Type of Impact* Length of
Impact
linear feet
Stream Name** Average Width
of Stream
Before Impact Perennial or
Intermittent?
leasespecify)
n/a Str. restoration 3500-3600 Hewlett's Creek 20' (BkfW) Perennial

Page 8 of 13
* List each impact separately and identify temporary impacts. Impacts include, but are not limited to: culverts and associated rip-rap,
dams (separately list impacts due to both structure and flooding), relocation (include linear feet before and after, and net loss/gain),
stabilization activities (cement wall, rip-rap, crib wall, gabions, etc.), excavation, ditching/straightening, etc. If stream relocation is
proposed, plans and profiles showing the linear footprint for both the original and relocated streams must be included.
** Stream names can be found on USGS topographic maps. If a stream has no name, list as UT (unnamed tributary) to the nearest
downstream named stream into which it flows. USGS maps are available through the USGS at 1-800-358-9616, or online at
www.usgs.gov. Several internet sites also allow direct download and printing of USGS maps (e.g., www.topozone.com,
www.mapquest.com, etc.).
Cumulative impacts (linear distance in feet) to all streams on site: 3527 if
4. Individually list all open water impacts (including lakes, ponds, estuaries, sounds, Atlantic
Ocean and any other water of the U.S.) below: N/A
Open Water Impact
Site Number
indicate on ma
Type of Impact* Area of
Impact
acres Name Waterbody
)
(if applicable) Type of Waterbody
(lake, pond, estuary, sound,
bay, ocean, etc.

* List each impact separately and identify temporary impacts. Impacts include, but are not limited to: fill, excavation, dredging,
flooding, drainage, bulkheads, etc.
5. Pond Creation
If construction of a pond is proposed, associated wetland and stream impacts should be
included above in the wetland and stream impact sections. Also, the proposed pond should
be described here and illustrated on any maps included with this application.
Pond to be created in (check all that apply): ? uplands ? stream
Describe the method of construction (e.g., dam/embankment, excavation,
draw-down valve or spillway, etc.): N/A
Proposed use or purpose of pond (e.g., livestock watering, irrigation, aesthetic, trout pond,
local stormwater requirement, etc.):
Size of watershed draining to pond: Expected pond surface area:
VII. Impact Justification (Avoidance and Minimization)
Specifically describe measures taken to avoid the proposed impacts. It may be useful to provide
information related to site constraints such as topography, building ordinances, accessibility, and
financial viability of the project. The applicant may attach drawings of alternative, lower-impact
site layouts, and explain why these design options were not feasible. Also discuss how impacts
were minimized once the desired site plan was developed. If applicable, discuss construction
techniques to be followed during construction to reduce impacts.
See attached restoration plan
? wetlands
installation of
Page 9 of 13
VIII. Mitigation
DWQ - In accordance with 15A NCAC 2H .0500, mitigation may be required by the NC
Division of Water Quality for projects involving greater than or equal to one acre of impacts to
freshwater wetlands or greater than or equal to 150 linear feet of total impacts to perennial
streams.
USACE - In accordance with the Final Notice of Issuance and Modification of Nationwide
Permits, published in the Federal Register on March 9, 2000, mitigation will be required when
necessary to ensure that adverse effects to the aquatic environment are minimal. Factors
including size and type of proposed impact and function and relative value of the impacted
aquatic resource will be considered in determining acceptability of appropriate and practicable
mitigation as proposed. Examples of mitigation that may be appropriate and practicable include,
but are not limited to: reducing the size of the project; establishing and maintaining wetland
and/or upland vegetated buffers to protect open waters such as streams; and replacing losses of
aquatic resource functions and values by creating, restoring, enhancing, or preserving similar
functions and values, preferable in the same watershed.
If mitigation is required for this project, a copy of the mitigation plan must be attached in order
for USACE or DWQ to consider the application complete for processing. Any application
lacking a required mitigation plan or NCWRP concurrence shall be placed on hold as
incomplete. An applicant may also choose to review the current guidelines for stream restoration
in DWQ's Draft Technical Guide for Stream Work in North Carolina, available at
http://h2o.enr.state.ne.us/ncwetlands/strmgide.html.
1. Provide a brief description of the proposed mitigation plan. The description should provide
as much information as possible, including, but not limited to: site location (attach directions
and/or map, if offsite), affected stream and river basin, type and amount (acreage/linear feet)
of mitigation proposed (restoration, enhancement, creation, or preservation), a plan view,
preservation mechanism (e.g., deed restrictions, conservation easement, etc.), and a
description of the current site conditions and proposed method of construction. Please attach
a separate sheet if more space is needed.
See attached restoration plan
2. Mitigation may also be made by payment into the North Carolina Wetlands Restoration
Program (NCWRP). Please note it is the applicant's responsibility to contact the NCWRP at
[phone] to determine availability and to request written approval of mitigation prior
to submittal of a PCN. For additional information regarding the application process for the
NCWRP, check the NCWRP website at http://h2o.enr.state.nc.us/wrp/index.htm. If use of
the NCWRP is proposed, please check the appropriate box on page three and provide the
following information:
Page 10 of 13
Amount of stream mitigation requested (linear feet):
Amount of buffer mitigation requested (square feet):
Amount of Riparian wetland mitigation requested (acres):
Amount of Non-riparian wetland mitigation requested (acres):
Amount of Coastal wetland mitigation requested (acres):
IX. Environmental Documentation (required by DWQ)
Does the project involve an expenditure of public (federal/state) funds or the use of public
(federal/state) land?
Yes ® No ?
If yes, does the project require preparation of an environmental document pursuant to the
requirements of the National or North Carolina Environmental Policy Act (NEPA/SEPA)?
Note: If you are not sure whether a NEPA/SEPA document is required, call the SEPA
coordinator at [phone] to review current thresholds for environmental documentation.
Yes ? No
If yes, has the document review been finalized by the State Clearinghouse? If so, please attach a
copy of the NEPA or SEPA final approval letter.
Yes ? No ?
X. Proposed Impacts on Riparian and Watershed Buffers (required by DWQ)
It is the applicant's (or agent's) responsibility to determine, delineate and map all impacts to
required state and local buffers associated with the project. The applicant must also provide
justification for these impacts in Section VII above. All proposed impacts must be listed herein,
and must be clearly identifiable on the accompanying site plan. All buffers must be shown on a
map, whether or not impacts are proposed to the buffers. Correspondence from the DWQ
Regional Office may be included as appropriate. Photographs may also be included at the
applicant's discretion.
Will the project impact protected riparian buffers identified within 15A NCAC 2B .0233
(Meuse), 15A NCAC 2B .0259 (Tar-Pamlico), 15A NCAC 2B .0250 (Randleman Rules and
Water Supply Buffer Requirements), or other (please identify )?
Yes ? No ® If you answered "yes", provide the following information:
Page 11 of 13
Identify the square feet and acreage of impact to each zone of the riparian buffers. If buffer
mitigation is required calculate the required amount of mitigation by applying the buffer
multipliers.
Zone* Impact
(square feet Multiplier Required
Mitigation
1 3
2 1.5
Total
* Zone 1 extends out 3U feet perpendicular from near bank of channel; Zone 2 extends an
additional 20 feet from the edge of Zone 1.
If buffer mitigation is required, please discuss what type of mitigation is proposed (i.e., Donation
of Property, Conservation Easement, Riparian Buffer Restoration / Enhancement, Preservation or
Payment into the Riparian Buffer Restoration Fund). Please attach all appropriate information as
identified within 15A NCAC 213 .0242 or.0260.
XI. Stormwater (required by DWQ)
Describe impervious acreage (both existing and proposed) versus total acreage on the site.
Discuss stormwater controls proposed in order to protect surface waters and wetlands
downstream from the property.
XII. Sewage Disposal (required by DWQ)
Clearly detail the ultimate treatment methods and disposition (non-discharge or discharge) of
wastewater generated from the proposed project, or available capacity of the subject facility.
XIII. Violations (required by DWQ)
Is this site in violation of DWQ Wetland Rules (15A NCAC 2H .0500) or any Buffer Rules?
Yes ? No
Is this an after-the-fact permit application?
Yes ? No
Page 12 of 13
XIV. Other Circumstances (Optional):
It is the applicant's responsibility to submit the application sufficiently in advance of desired
construction dates to allow processing time for these permits. However, an applicant may
choose to list constraints associated with construction or sequencing that may impose limits on
work schedules (e.g., draw-down schedules for lakes, dates associated with Endangered and
Threatened Species, accessibility problems, or other issues outside of the applicant's control).
Applic
(Agent's signa
19,7-0
/
A nt' Signature Date
is v) d only if an authorization letter from the applicant is provided.)
Page 13 of 13
imap://[e-mail]:143/fe...
Subject: Re: Hewlett's Creek Stream Restoration
From: Kristin Miguez <[e-mail]>
Date: Fri, 03 Sep 2004 09:00:41 -0400
To: Alicia DuClos <[e-mail]>
CC: Cyndi Karoly <[e-mail]>, Marc Recktenwald <[e-mail]>
Thanks Alicia. I'll submit the required information early next week.
Kristin E. 1ligucz, Project Manager
NCll1 NR Ecosystem Enhancement Pro-ram (www.nceep.net)
1652 Mail Service Center. Raleigh, INC 27699-1652
Phone [phone], Fax [phone]
Alicia DuClos wrote:
Kristin,
In order for the Hewlett's Creek Stream Restoration project (#03-1207) to become reactivated, DWQ
needs the following:
1. A formal letter stating the reasons why the project was withdrawn and requesting the reactivation
of the project.
2. Five (5) copies each of the updated PCN application and restoration plans.
Please continue to use the DWQ project # 03-1207.
Thank you,
Alicia
1 of 1 913/2004 2:04 PM
imap://[e-mail]:143/fe...
Subject: Re: Trying to find a copy of a 401 Permit Z c
From: Kristin Miguez <[e-mail]> ?2
Date: Mon, 30 Aug 2004 15:02:44 -0400 1 o D
To: Alicia DuClos <[e-mail]>
CC: Marc Recktenwald <[e-mail]>
Alicia,
Thanks for the quick response. This project has become an active project again, and I was not aware
that Mac had previously withdrawn the 401 application. Can you tell me if you still have a copy of the
restoration plan and application that were submitted last year? Please let me know if I need to resubmit
the information, and I'll do so as soon as possible. We hope to begin construction on this project in the
coming months.
Kristin
Alicia DuClos wrote:
Kristin,
On November 14, 2003 Mac Haupt with WRP/EEP notified the Wilmington Regional Office that the
Hewlett's Creek project was no longer being requested. Therefore, the application was withdrawn and
a 401 was not issued.
If you need additional info, do not hesitate to contact me.
Alicia DuClos
NC DENR DWQ Wetlands/401 Certification Unit
919-715-3404
Kristin Miguez wrote:
Alicia,
Can you please forward me a copy of a 401 permit that should have been issued last fall for one of
our stream restoration projects? I have a copy of the PCN application that was forwarded to DWQ
in September 2003, but can't find where we ever received the permit.
The project is the Hewlett's Creek Stream Restoration at Pine Valley Country Club in Wilmington,
NC. At the time the PCN application was submitted, we listed the Owner/Applicant as the NC
Wetlands Restoration Program.
Please fax a copy of the permit to my attention at 715-2001 at your earliest convenience.
thanks,
Kristin
Kristin G. Miguez, Project Manager
1 of 2
8/31/2004 8:41 AM
imap://alicia.duclos%40dwq.denr.ncmai1.net @cros.ncmail.net:143/fe...
NCDENR Elcosystcm Enhancement Ili-w,ram (www.nceep.net)
1652 Mail Service Center, Ralci,Jh, NC 27699-1652
Phonc [phone], Pay [phone]
2 of 2 8/31/2004 8:41 AM
MEMORANDUM
TO: John Dorney Regional Contact: Noelle Lutheran
Non-Discharge Branch WQ Supervisor: Birk Shiver
Date:
SUBJECT: WETLAND STAFF REPORT AND RECOMMENDATIONS
Facility Name Hewlett's Creek Stream Resoration
Project Number 03 1207
Recvd From WRI'
Received Date 9/26/03 Recvd By Region
Project Type stream restoration project
County New Hanover
County2
Region Wilmington
Certificates Stream Stream Impacts (ft.)
Permit Wetland Wetland Wetland Stream Class Acres Feet
??r:r r??fir.-lri
Type Type Impact Score Index Prim. Supp• Basin Req. Req.
27 Stream O Y O N 18-87-26 SA HQ?V 30,624. 3,527.00 F_ F
F-F-o Y _0N F_If F_F_-F__F_ F_F_
Mitigation Wetland
MitigationType Type Acres Feet
Stream restoration Stream rF_ 3,527.00
?I
Is Wetland Rating Sheet Attached? O Y ON Did you request more info? O Y ON
Have Project Changes/Conditions Been Discussed With Applicant? Q Y O N
Is Mitigation required? O Y O N
Recommendation: O Issue O Issue/Cond O Deny
Provided by Region: Latitude (ddmmss) Longitude (ddmmss)
Comments:
On Friday, November 14, Mac Haupt with WRP/EEP notified this office that this eject has been
offic i ydropned and a permit is no long .re. being requested, NML
cc: Regional Office
Central Office Page Number 1
Triage Check List
Date: U Project Name:
?r??
DWQ#:
County:
To: ? ARO Mike Parker
? FRO Ken Averitte
? MRO Mike Parker
? RRO Steve Mitchell
From: ,ed

? WaRO Deborah Sawyer
WiRO Joawie--S x uis
WSRO Jennifer Frye
Telephone : (919)/,?`v?YcP/ ,
The file attached is being forwarded to your for your evaluation.
Please call if you need assistance.
? Stream length impacted
? Stream determination
? Wetland determination and distance to blue-line surface waters on USFW topo maps
? Minimization/avoidance issues
? Buffer Rules (Meuse, Tar-Pamlico, Catawba, Randleman)
? Pond fill
? Mitigation Ratios
? Ditching
? Are the stream and or wetland mitigation sites available and viable?
? Check drawings for accuracy
? Is the application consistent with pre-application meetings?
? Cumulative impact concern
Comments: X?f 0(J ? -e-_ i .7? zf'- r 1'?
"a /'enr1 o/' '_?2 A,.ei 'rte

t
Office Use Only: Form Version October 2001
USACE Action ID No. DWQNo:
If any particular item is not applicable to this project, please enter "Not Applicable" or "N/A" rather than
leaving the space blank.
' C
Processing
1.
AIETfANDS/?Io1 UP
1. Check all of the approval(s) requested for this project: SFrP t, ?, ?ou
® Section 404 Permit
F-1 /gyp
Section 10 Permit i????E???l.??''?E?T?Q??
® 401 Water Quality Certification C
? Riparian or Watershed Buffer Rules
2. Nationwide, Regional or General Permit Number(s) Requested: Nationwide 27
3. If this notification is solely a courtesy copy because written approval for the 401 Certification
is not required, check here: ?
4. If payment into the North Carolina Wetlands Restoration Program (NCWRP) is proposed for
mitigation of impacts (see section VIII - Mitigation), check here: ?
II. Applicant Information
2
1. Owner/Applicant Information
Name: NC Wetlands Restoration Program
Mailing Address: 1619 Mail Service Center Raleigh, NC 27699-1619
Telephone Number: 919-733-5208 Fax Number: 919-733-5321
E-mail Address [e-mail]
Agent Information (A signed and dated copy of the Agent Authorization
attached if the Agent has signatory authority for the owner/applicant.)
Name:
Company Affiliation:
Mailing Address:
Telephone Number: Fax Number:
E-mail Address:
letter must be
Page 5 of 12
III. Project Information
9
Attach a vicinity map clearly showing the location of the property with respect to local
landmarks such as towns, rivers, and.roads. Also provide a detailed site plan showing property
boundaries and development plans in relation to surrounding properties. Both the vicinity map
and site plan must include a scale and north arrow. The specific footprints of all buildings,
impervious surfaces, or other facilities must be included. If possible, the maps and plans should
include the appropriate USGS Topographic Quad Map and NRCS Soil Survey with the property
boundaries outlined. Plan drawings, or other maps may be included at the applicant's discretion,
so long as the property is clearly defined. For administrative and distribution purposes, the
USACE requires information to be submitted on sheets no larger than 11 by 17-inch format;
however; DWQ may accept paperwork of -any size. DWQ prefers full-size construction
drawings rather than a sequential sheet version of the full-size plans. If full-size plans are
reduced to a small scale such that the final version is illegible, the applicant will be informed that
the project has been placed on hold until decipherable maps are provided.
Name of project Hewlett's Creek Stream Project
2. T.I.P. Project Number or State Project Number (NCDOT Only):
3. Property Identification Number (Tax PIN): _
4. Location
County: New Hanover Nearest Town: Wilmington
Subdivision name (include phase/lot number):
Directions to site (include road numbers, landmarks, etc.): NC132 to Hewlett's Creek to
Longstreet
5. Site coordinates, if available (UTM or Lat/Long):
(Note - If project is linear, such as a road or utility line, attach a sheet that separately lists the
coordinates for each crossing of a distinct waterbody.)
6. Describe the existing land use or condition of the site at the time of this application: Golf
Course
7. Property size (acres): 9 ac
S. Nearest body of water (stream/river/sound/ocean/lake): Atlantic Ocean
River Basin: Cape Fear
(Note - this must be one of North Carolina's seventeen designated major river basins
River Basin map is available at http://h2o.enr.state.nc.us/admin/maps/.)
The
10. Describe the purpose of the proposed work: Stream Restoration
Page 6 of 12
1
CITY OF WILMINGTON STORMWATER POND
1
1.) Area shall be graded smooth upon completion of earthwork activities, with a
slope toward the storm water pond and a maximum side slope of 3:1
2.) Area shall be stabilized with temporary seed upon completion of earthwork
3.) Area shall be sprigged with Bermuda grass variety between May 15th and
June 15th, the contractor shall coordinate with the golf course superintendent
LEGEND
CROSS VANE * CART PATH
*
-

•See Detail 13 (C-5) 'See Detcl 15 (C-5)
LOG
VANE CULVERT CROSSING
GV
-See Detail 11 (C-5) -Si,. Detal 7 C-7)
ROOT WADS * RETAINING WALL

-See Detm1 112 (C-A •See Deta1 16 C-9)
NOTE: Structure placement on Plan Sheets
ore for location only. Actual placement shall
be directed by Resident Engineer
DETAIL
PRCResD y..w,re+o

3f
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GRADING LIMITS OF CONSTRUCTCN .. ..
j ! PERMANENT EASEMENT %? .
T_Vi C^. \''.Tfi'v'Cl0'1 n'3?DNAY ?i
TAI'._ 14 _a,)
CITY OF MUnNCTDN SENERUNE - j
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PROJECT NO.
FILENAME HE'ALETTAWG
SHEET NO.
C-2
ORANING NO
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STREAM (SREV) I
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/ SEE DETAL 15 (C-8)
BETWEEN STA: 18+40 TO STA:19+61
!_TY M1LMINGTON SEWERLANE THE CHANNEL WILL NOT BE REALIGNED
•j.

CU RVE TABLE
CURVE LENGTH RADIUS
C- 1 69.6 39.5
C- 2 22.3 32.0
C- 3 49.8 34.0
C- 4 25.0 34.0
C- 5 43.3 39.0
C- 6 72.1 42.0
C- 7 5&1 38.0
C- 8 69.2 42.0
C- 9 3&9 36.0
C- 10 29.0 40.0
C- 11 5&7 43.0
C- 12 417 35.0
C- 13 35.5 33.0
F 14 36.1 34.0
NOTE: The listed Radius of Curvatures are
measured from the stream centerline.
Actual Radius of Curvatures maybe
adjusted by Resident NCSU Engineer
LINE TABLE
LINE LENGTH BEARING NORTHING EASTING
L- 1 25.5 N2711'58 151485 2332861
L- 2 31.9 NST40'33•W 161518 2332892
L- 3 31.9 N13S8'53'W 151554 2332951
L- 4 53.9 N3819'54 181507 2332952
L- 5 38.5 N44'01'1 1-W 161891 2332983
L- 6 19.4 N7325'15' 161780 2332973
L- 7 37.5 N21'06.04•W 161832 2333026
L- 8 41.9 N 1' •W 181914 2333054
L- 9 29.8 N21TY35•E 161927 2333125
L- 10 42.4 N70V6'18• 181972 2333159
L- 11 35.9 Nn-50'16'w 162065 2333275
L- 12 30.3 N7527'44• 162150 2333293
L- 13 24.4 Ni '06'09•W 182192 2333344
L- 14 31.7 N70'48'47• 162246 2333357
NOTE: The listed Northing and Easting Columns
represent the head of the appropriate riffle section
along the centerline of the stream. Actual riffle
starting locations, bearing and lengths maybe adjusted
by Resident NCSU Engineer
LEGEND
CROSS VANE * *
CART PATH
-
-See Deta1 IS (C-6) •See Detoi 15 (C-8)
LOG VANE CULVERT CROSSING
`
-See Deto1 11 (C-8) -See Detoi 1 (C-7)
ROOT WADS * RETAINING WALL
f4sk. N !

-See Detod 11 d-8) -See Deto9 16 (C-9)
NOTE: Structure placement on Plan Sheets
are for location only. Actual placement shall
be directed by Resident Engineer
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PROJECT NO.
FILENAME HEwtETT.Dwc
SHEET NO.
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measured from the stream centerline. represent the head of the appropriate riffle section
Actual Radius of Curvatures maybe along the centerline of the stream. Actual riffle
adjusted by Resident NCSU Engineer starting locations, bearing and lengths maybe adjusted
by Resident NCSU Engineer
/
/
/
/
/
GRADNO 11111TS Or CONSTRUCMON
PER-ENT EASEMENT
23+
43
R
: DETAL 7 (C-7)
CU RVE TABLE
CURVE LENGTH RADIUS
C- 15 37.3 42.0
C- 18 35.0 40.0
C- 17 57.8 34.0
C- 18 5&1 30.0
C- 19 67.7 30.0
C- 20 68.4 30.0
C- 21 27.2 35.0
C- 22 17.0 38.0
C- 23 30.0 35.0
C- 24 32.6 38.0
C- 25 34.2 35.0
C- 28 4
N 37.0
C- 27 4.8
I 73.0
C- 28 59.4 39.0
NOTE: The listed Radius of Curvatures are
measured from the stream centerline.
Actual Radius of Curvatures maybe
adjusted by Resident NCSU Engineer

q STREAM (SREV)
LINE TABLE
UNE LENGTH BEARING NORTHING EASTING
L- 15 27.1 N0915'44W 162287 2333402
L- 18 57.8 N55'24',TrE 162347 2133411
L- 17 33.5 N 'W 182411 2333472
L- 18 34.4 N 0 ' 182482 2333500
L- 19 33.1 N 'W 182520 2333582
L- 20 21.7 N61'4 ' 'W 162587 2333583
L- 21 28.6 N 162613 2333841
L- 22 25.2 N 162683 2333630
L- 23 18.5 N 1 182788 2333852
L- 24 2&2 N 9 'W 162788 2333884
L- 25 2&6 N ' 7' 162777 2333938
L- 25 28.1 N 04' 'W 182796 2333991
L- 27 30.1 N49'4 162783 2134045
L-28 29.0 N 3'S'W 162800 1&4
1
1
0

29.6
N 6'
162778 ,
,
3
1
NOTE: The listed Northing and Easting Columns
represent the head of the appropriate riffle section
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by Resident NCSU Engineer

LEGEND
CROSS VANE * CART PATH

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RECEIVED
SFP 3 2004
NC ECOSYSTEM
Stream Restoration Plan ENHANCEMENT PROGRAM
Hewlett's Creek
New Hanover County, North Carolina
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PROGUMA
2739
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August 31, 2004
Biological &,
Agricultural
Engineering
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I
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Biological & Agricultural Engineering
Weaver Labs, Campus Box 7625
North Carolina State University
Raleigh, North Carolina 27695
SANDS/401 GROUP
SEP 0 T 2004
WATER 4UALJT?SEOT!
ON
. y
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
TABLE OF CONTENTS
1.0 INTRODUCTION ............................................................1
1.1 PROJECT DESCRIPTION ..........................................2
1.2 GOALS AND OBJECTIVES ........................................2
1.3 STREAM SURVEY METHODOLOGY ...........................2
1.3.1 Stream Delineation - Classification .........................4
1.3.2 Bankfull Verification ..........................................4
2.0 EXISTING CONDITIONS ...................................................
6
2.1 WATERSHED ....................................................... .. 6
2.1.1 General Description of the Watershed .................... ..6
2.1.2 Surface Waters Classification ............................. ...6
2.1.3 Soils of the Watershed .........................................6
2.1.4 Land Use of the Watershed ...................................8
2.2 RESTORATION SITE ................................................8
2.2.1 Site Description .............................................. ..8
2.2.2 Existing Stream Characteristics ............................ ..8
2.2.3 Soils of the Restoration Site ... . ............................ ..9
2.2.4 Terrestrial Plant Communities .............................. ..9
2.2.4.1 Managed Land ..................................... .12
2.2.4.2 Bottomland Forrest ............................... 12
2.2.4.3 Upland Hardwood Forest ........................ 12
2.2.4.4 Possible Invasive Flora ........................... 12
2.2.5 Wildlife Observations ..... .................................13
2.2.5.1 Possible Invasive Wildlife .......................... 13
2.2.6 Endangered Species ........................................... 13
2.2.6.1 Endangered Flora .................................. 13
2.2.6.1 Endangered Fauna ................................. 14
3.0 REFERENCE REACHES ...................................................15
3.1 JOHANNAH CREEK ...............................................15
3.2 PANTHER BRANCH ...............................................15
3.3 BATORORA BRANCH ............................................15
4.0 STREAM CHANNEL DESIGN ...........................................17
4.1 RESTORATION TECHNIQUES .................................22
4. 1.1 Dimension ......................................................
22
4.1.2 Pattern ..........................................................
22
4.1.3 B edform ........................................................23
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.1.4 Riparian Areas ........ ........................................23
4.2 SEDIMENT TRANSPORT . ........................................26
4.3 FLOODING ANALYSIS ... ........................................26
4.4 STRUCTURES ............... ........................................27
4.4.1 Cross Vane .....................................................27
4.4.2 Root Wads ............. ........................................27
4.4.3 Single Vanes .......... .........................................28
5.0 HABITAT RESTORATION ...............................................29
5.1 VEGETATION .......................................................29
5.2 RIPARIAN BUFFERS ..............................................30
5.2.1 Temporary Seeding ..........................................30
6.0 MONITORING ............................................................... 31
6.1 STREAM CHANNEL ...............................................31
6.2 VEGETATION ....................................................... 31
6.3 MACROINVERTEBRATES .......................................32
7.0 REFERENCES ...............................................................33
LIST OF TABLES
Table 1. Bank Erosion Potential ...............................................10
Table 2. Middle Branch of Hewlett's Creek Morphology .................16
Table 3. Priorities, Desc. & Summary for Incised River Restoration... 18
Table 4. Stream Monitoring Practices .......................................31
LIST OF FIGURES
Figure 1 Site Location ............................................................3
Figure 2 Watershed Axial ...................................................... ..7
Figure 3 Soils Map .............................................................. 11
Figure 4 Hewlett's Creek Restoration Plan .................................. 19
Figure 5 Hewlett's Creek Restoration Plan ................................. 20
Figure 6 Hewlett's Creek Restoration Plan .................................. 21
Figure 7 Typical Cross-Sections .............................................. 24
Figure 8 Proposed Longitudinal Profile ...................................... 25
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
1.0 INTRODUCTION
The North Carolina Wetlands Restoration Program (NCWRP) has identified The Middle
Branch of Hewlett's Creek as a potential stream restoration site. Hewlett's Creek drains
into the Greenville Sound, the Middle Branch of Hewlett's creek (NCDWQ Stream Index
Number 18-87-26 SA HQW) is located on urban land in the southeast corner of
Wilmington in New Hanover County, North Carolina (Figure 1).
Arcadis first identified Hewlett's Creek as a potential restoration site in a feasibility
report to NCWRP. NCSU is completing the design and will conduct construction
oversight of the restoration of the middle branch of Hewlett's Creek. The portion of
Hewlett's creek that is being evaluated for restoration is within the property boundaries
of the Pine Valley Country Club. The Country Club Membership met on March 17`h of
2003 and voted to allow WRP to fund a restoration project focused on the Middle Branch
of Hewlett's Creek.
The Middle Branch of Hewlett's Creek has areas of significant active bank erosion
throughout the proposed project limits. There is evidence of historic straightening and
degradation resulting from this straightening. Thinning and removal of riparian
vegetation has also accelerated the degradation process. The incised condition of the
existing channel is accelerating the erosion process by forcing the channel to contain
larger then bankfull storm events.
The restoration site is located entirely within the property boundaries of the Pine Valley
Country Club. A City of Wilmington 16" RCP sewer line is located along the entire
length of the reach that is being considered for restoration. The sewer line crosses the
existing channel twice within the reach and is offset from the existing channel by a range
of loft to 40ft. There are two power-lines and numerous irrigation lines for the golf
course within the project limits. The Middle Branch of Hewlett's Creek has many urban
constraints, but should be an excellent potential restoration site, and . ideal for
demonstration and education.
Restoration requires determining how far the stream has departed from its natural
stability and then, establishing the stable form of the stream under the current hydrologic
conditions within the drainage area. The proposed restoration will construct a stable
meander geometry, modify channel cross-sections, and establish a floodplain at the
existing stream elevation, thus, restoring a stable dimension, pattern and profile. This
restoration is based on analysis of current watershed hydrologic conditions, evaluation of
the project site, and assessments of stable reference reaches. The following
recommendations are included in this restoration plan:
• Form a stable channel with the proper dimension, pattern and profile.
• Establish a floodplain along the stream channel.
• Place natural material structures in the stream to improve stability and enhance
aquatic habitat.
• Stabilize stream banks with herbaceous and woody vegetation
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
1.1 PROJECT DESCRIPTION
The Middle Branch of Hewlett's Creek project site is located in Hanover County, North
Carolina. The project is fully contained within the property of one landowner (The Pine
Valley Country Club). The project reach is bounded by The Long Street Drainage Cannel
to the west (upstream) and a 78" RCP culvert for Robert E. Lee Drive to the east
(downstream) (Figure 1).
1.2 GOALS AND OBJECTIVES
This project has the following goals and objectives:
1. Restore 3527 linear feet of The Middle Branch of Hewlett's Creek (as measured
along the centerline)
2. Provide a stable stream channel that neither aggrades nor degrades while maintaining
its dimension, pattern, and profile with the capacity to transport its watershed's water
and sediment load.
3. Improve water quality and reduce further property loss by stabilizing eroding stream
banks.
4. Establish a new floodplain at the existing stream elevation.
5. Improve aquatic habitat with the use of natural material stabilization structures such
as root wads; log vanes, woody debris and a riparian buffer.
6. Provide aesthetic value, wildlife habitat and bank stability through the creation or
enhancement of a riparian zone.
1.3 STREAM SURVEY METHODOLOGY
The US Forest Service General Technical Report RM-245, Stream Channel Reference
Sites: An Illustrated Guide to Field Technique is used as a guide when taking field
measurements. Accurate field measurements are critical to determine the present
condition of the existing channel, conditions of the floodplain, and watershed drainage
patterns.
2
The Middle Branch of Hewlett's Creek
New Hanover County, NC
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New Hanover County, NC North
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FIGURE I
SITE LOCATION
RESTORATION PLAN
3
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
NCSU contracted with W. K. Dickson to conduct a topographic survey of the restoration
site in August 2002. This mapping along with field measurements taken by NCSU staff
was used to evaluate present conditions, new channel alignment and grading volumes.
Mapping also provided locations of property pins, large trees, vegetation lines, and
culverts, roads, utilities and elevation contours.
A windshield survey was also conducted to determine the existing conditions within the
watershed. The watershed is fully (>90%) developed with residential dwellings and has
an area of 1.5 sq. miles
During the site visits, three cross-sections were taken using standard differential leveling
techniques. These cross-sections were used to gather detail on the present dimension and
condition of the channel. Bankfull cross-sectional area was calculated using the bankfull
features, the bankfull area at riffles varied between 26 sqft to 31 sqft.
1.3.1 Stream Delineation Criteria - Classification
Dave Rosgen developed his stream classification system in order to accomplish the
following:
1) Predict a river's behavior
2) Develop specific hydraulic and sediment relationships for a given stream type and its
state
3) Provide a mechanism to extrapolate site-specific data ,to stream reaches having
similar characteristics
4) Provide a consistent frame of reference for communicating stream morphology and
condition among a variety of disciplines and interested parties
The Rosgen Stream Classification System is based on five criteria: width/depth ratio,
entrenchment ratio, slope, sinuosity, and channel materials. All cross-sections were
classified using this system.
1.3.2 Bankfull Verification
The foundation of Dave Rosgen's classification system is the concept of bankfull stage,
which is the point of incipient flooding. The width/depth and entrenchment ratios
described above depend on the correct assessment of bankfull. If bankfull is incorrectly
determined in the field, the entire restoration effort will be based on faulty data. It is
important to verify the physical indicators observed in the field with either gage data or a
regional curve to ensure the correct assessment of the bankfull stage.
The bankfull stage is determined in the field using physical indicators. The following is a
list of commonly used indicators that define bankfull (Rosgen, 1996):
4
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
• The presence of a floodplain at the elevation of incipient flooding.
• The elevation associated with the top of the highest depositional feature (e.g. point
bars, central bars within the active channel). These depositional features are
especially good stage indicators for channels in the presence of terrace or adjacent
colluvial slopes.
• A break in slope of the bank and/or a change in the particle size distribution, since
finer material is associated with deposition by overflow, rather than deposition of
coarser material within the active channel.
• Evidence of an inundation feature such as small benches below bankfull.
• Staining of rocks.
The most dominant bankfull indicators along The Middle Branch of Hewlett's Creek are
high scour lines and breaks in slope along the backs of narrow point bars.
The most common method of verifying bankfull stage is to compare the field determined
bankfull stage with measured stages at a stream gauging station. This calibration can be
performed if there is a stream gage within the study area's hydro-physiographic region.
In un-gauged areas, Dave Rosgen recommends verifying bankfull with the development
of regional curves. The regional curves normally plot bankfull discharge (QbkD, cross-
sectional area, width, and depth as a function of drainage area. The cross-sectional areas
of The Middle Branch of Hewlett's Creek was plotted on the Urban, Coastal Regional
Curve of North Carolina developed by the North Carolina State University (NCSU)
Water Quality Group, 2003 to help verify bankfull stage.
Data obtained from field surveys was used to compute the morphological characteristics
shown on the graph. The cross-sectional area for The Middle Branch of Hewlett's Creek
plots along the trend line for the Urban Regional Curve. The bankfull cross-sectional area
for the design channel was determined from evaluating the North Carolina regional curve
relationships and comparing them to the reference reach sites surveyed near the
restoration site. HEC-RAS was used to verify the design cross-sectional area for the
project.
5
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.0 EXISTING CONDITIONS
2.1 WATERSHED
2.1.1 General Description of the Watershed
The Middle Branch of the Hewlett Creek is a second order stream, is located within the
Coastal Physiographic Province of the Cape Fear River Basin (USGS Cataloging Unit). 03?3'S
The watershed is located in the Southeast corner of Wilmington, in New Hanover
County, North Carolina. The headwaters of the project originate approximately 2 miles to
the north-northeast of the restoration site. From the headwaters, Hewlett flows for
approximately 4.0 miles before emptying into the Greenville Sound just southwest of
Masonboro inlet. The land use within the study is mixed residential, commercial, and an
18-hole golf course.
The watershed is approximately 1.5 square miles (Figure 2). The watershed is oriented
north to south bending to the east before the project site. The topography ranges from
gently sloping to flat with relatively flat former floodplain that has be detached by
channeling the stream the middle of the past century. Land surface elevations range from
approximately 30 to 55 feet above mean sea level.
2.1.2 Surface Waters Classification
Surface waters in North Carolina are assigned a classification by the DWQ that is
designed to maintain, protect, and enhance water quality within the state. Hewlett's Creek
?? - c7 a (NCDWQ Stream Index Number) is classified as a class SA HQW water body
(NCDENR, 2001). SA HQW water resources are waters protected for shellfish
propagation and survival, fishing, wildlife, secondary recreation, and agriculture.
2.1.3 Soils of the Watershed
The soils found in the watershed and adjacent to the stream can help determine the bed
and bank materials occurring in the stream. The Rosgen stream classification system uses
average particle size within the bankfull channel to help classify the stream. Knowing the
make up of the soils in the watershed, assists in understanding the anticipated bed-load
and sediment transport capacity of the stream.
Soils in upland areas within the watershed consist primarily of sand and urban complex
(draft maps and descriptions of the soils in the project area - New Hanover County Soil
Survey Office, Natural Resources Conservation Service [NRCS]). Depth to bedrock is
mapped as greater than 60 inches for the soils in the watershed. Soils in the side slopes
shoulders and summits of ridges include Baymeade-Urban Land complex 1 to 6 percent
slopes, and Rimini sand 1 to 6 percent slopes
6
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New Hanover County, NC
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New Hanover County, NC North
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RESTORATION PLAN
7
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.1.4 Land Use of the Watershed
Land use within the watershed is predominately urban residential (Figure 2). Evaluation
of a 1998 aerial photo obtained from New Hanover Country reveals that approximately
90% of the watershed is built out with single home residential areas, roads, businesses
and golf courses, with the remaining being water detention and forested urban land that is
not likely to be developed. The total percent impervious cover in the watershed is
approximately 20%-30%
2.2 RESTORATION SITE
The following sections provide a description of existing site conditions. This includes the
current stream conditions, soils, and surrounding plant communities.
2.2.1 Site Description
The Middle Branch of Hewlett's Creek restoration site begins approximately 4.0 miles
from its confluence with the Greenville Sound. The project is located within the property
boundaries of The Pine Valley Country Club. The middle Branch of Hewlett's Creek
flows from the west to east through a 0 to 35-foot wide floodplain. The majority of the
floodplain is located on the within the ditched channel of Hewlett's creek. The
floodplain typically ends abruptly at the toe of the adjoining steep slopes. A former
terrace extends along the entire length of the project and is 75 to 300 feet wide the
majority of the terrace is presently being used as fairway for the adjacent golf course.
The channel has long straight reaches with very minimal meanders. Channel sinuosity for
the entire reach is 1.05. High banks and areas of severe bank erosion can be found
throughout the project reach.
The main factor in the degradation and impairment for the Middle Branch of Hewlett's
Creek appears to be historic straightening of the channel and removal of riparian
vegetation. Straightening has increased the channel slope and decreased the stream
sinuosity. Erosion has caused increased sediment supply and channel widening. This has
combined to lead to the development of central bars in several straight sections of the
channel. Further development of central bars will increase erosion and lateral migration
of the channel.
2.2.2 Existing Stream Characteristics
Field surveys of the existing stream channel and site were conducted in August 2002.
The Middle Branch of Hewlett's Creek Restoration Site can be typically defined as a
predominantly straight channel with poor habitat. Stream banks are steep with areas of
active erosion. Long straight sections of the channel have central bars forming; indicating
the channel is over-wide. Instead of focusing the flow along the thalweg, the central bars
deflect the stream-flow toward the banks and accelerate bank erosion.
8
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
flow toward the banks and accelerate bank erosion.
Riffle bankfull widths range, from 24 to 30 feet with mean depths
ranging from 1.2 to 1.5 feet. The cross-sectional areas for these riffles range from 26.0 to
31.5 square feet. All of the cross-sections were taken within the reach to be restored. All
cross-sections classed as type-F or G channels as the amount of incision increases
downstream. The stream has the following average characteristics:
Bankfull Width: 27 feet
Bankfull Cross-sectional Area: 30 square feet
Bankfull Mean Depth: 1.3 feet
Bankfull Maximum Depth: 4.1 feet
Average Water Surface Slope: 0.002 feet/feet
Entrenchment Ratio: >6.0
Sinuosity: <1.05
Bank Height Ratio 2.0
The entire length of channel within the restoration site was rated using the Bank Erosion
Hazard Index (BEHI). The most likely bank to erode was assessed throughout the reach.
The reach was subdivided into sections with similar erosional characteristics such as
surface protection, root depth, root density, and bank angle. Results are listed in Table 1.
The overall restoration reach has a BEHI rating of high, although two sections had a
BHEI rating of very high and extreme. It is likely these two areas will expand as erosion
continues. The main cause of the very high and extreme ratings are due to the lack of
significant deep rooting vegetation and surface protection. Restoration will reestablish
deep rooting vegetation along the banks throughout the entire reach.
2.2.3 Soils of the Restoration Site
According to the preliminary soil maps for New Hanover County, soils adjacent to the
Middle Branch of Creek within the restoration site are mapped as Rimini, Baymeade and
Lynn Haven soils (Figure 3). Investigation of the soils adjacent to the stream indicates
that all three soils are present, although Lynn Haven is the most common. Lynn Haven is
a fine sandy soil that is well drained. These permeable soils occur on nearly level
floodplains along creeks and rivers. The original wetland soils where most likely covered
and removed when the golf course was built up and the creek was straightened
Soil textures encountered include sand and fine sand. The seasonal high water table was
observed to be greater than 40 inches for most soils within the project. Slopes range from
0 to 6 percent.
2.2.4 Terrestrial Plant Communities
The following sections describe the existing plant communities on and adjacent to the
restoration site. For purposes of this project, three plant communities are described:
Managed Land, Bottomland Forest, and Upland Hardwood Forest. Nomenclature follows
Radford (1968).
9

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New Hanover County, NC
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N.C. Well=& Restoration Program
FIGURE 3
SOILS MAP
RESTORATION PLAN
11
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.2.5 Wildlife Observations
Wildlife and signs of wildlife were noted during on-site visits, however, a formal wildlife
survey was not performed. Tracks of white tailed deer (Odocoileus virgin ialius) and
raccoon (Procyon Iotor) were observed along the stream banks. A variety of birds were
observed in the thickets and shrubs surrounding the stream channel and forest, including:
various sparrows.
2.2.5.1 Possible Invasive Wildlife
The following species were identified during site visits to the Middle Branch of Hewlett's
Creek; Asian tiger mosquito (Aedes albopictus), Bullfrog (Rana catesbeiana) (auditory
identification), European gypsy moth (Lymantria dispar), and European starling (Stunius
vulgaris). The bullfrog is listed based on auditory identification by one of the project
researchers. The gypsy moth is listed based on visual identification of nests. The
mosquito and starling are listed due to their ubiquitous nature.
2.2.6 Endangered Species
The NCSU design team has not identified endangered plant or animal species or any such
habitat that would support the endangered species listed in this section. The NCSU
design team has made multiple visits to the Pine Valley Country Club and the restoration
site. Below is a list obtained from Natural Heritage, of the endangered of concern for
New Hanover County.
2.2.6.1 Endangered Flora
Vascular Plants:
Cooley's meadowrue
Rough-leaved loosestrife
Seabeach amaranth
Bog St. John's-wort
Carolina asphodel
Carolina bishopweed
Carolina beaksedge
Chapman's sedge
Coastal golden rod
"Dune bluecurls"
Pickering's dawnflower
Pondspice
Sandhills milkvetch
Savanna indigo-bush
Spiked medusa
Spring-flowering goldenrod
Tough bumelia
Endangered
Endangered
Threatened
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
12
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Venus flytrap Federal Species of Concern
2.2.6.2 Endangered Fauna
Vertebrates:
Red-cockaded woodpecker Endangered
Shortnose sturgeon Endangered
West Indian Manatee Endangered
American Alligator Threatened
Green sea turtle Threatened
Loggerhead sea turtle Threatened
Piping Plover Threatened
Carolina gopher frog Federal Species of Concern
Eastern painted bunting Federal Species of Concern
Mimic glass lizard Federal Species of Concern
Northern pine snake Federal Species of Concern
Southeastern myotis Federal Species of Concern
Southern Hognose snake Federal Species of Concern
Invertebrates:
Arogos skipper
Buchholz's dart mouth
Cape Fear threetooth
Croatan crayfish
Magnificent rams-horn
Rare skipper
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
13
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Table 2. Middle Branch of Hewlett's Creek Mnrnhnlnnv (FYictinn
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
3.0 REFERENCE REACHES
Reference reaches were utilized on which the morphological characteristics were
measured to determine a range of values for the stable dimension, pattern, and profile of
the proposed channel. The following sections include a detail of three of the reference
reaches that were used for design of the restoration plan for the Middle Branch of
Hewlett's Creek. The reference reaches used along with the bankfull area, and current
constraints as the base for the preliminary design.
3.1 JOHANNAH CREEK
The Johannah creek has a drainage area of 1.18 square miles. Angela Moreland of the
NCSU Water Quality group completed the stream survey of Johannah creek in the
summer of 2001. The stream had a bankfull channel width of 10.4 feet and a bankfull
mean depth of 0.8 feet. Johannah Creek is a C5 stream type from Rosgen Classification
system. The morphological characteristics of this reference stream are included in Table
2.
3.2 PANTHER BRANCH
The Panther branch has a drainage area of 1.69 square miles. Angela Moreland of the
NCSU Water Quality group completed the stream survey of Panther branch in the
summer of 2001. The stream had a bankfull channel width of 11.5 feet and a bankfull
mean depth of 1.6 feet. Panther Branch is an E5 stream type from Rosgen Classification
system. The morphological characteristics of this reference stream are included in Table
2.
3.3 BATORORA BRANCH
Angela Moreland of the NCSU Water Quality group completed the stream survey of
Batorora branch in the summer of 2001. The stream had a bankfull channel width of 15.5
feet and a bankfull mean depth of 1.5 feet. Batorora Branch is an E5 stream type from
Rosgen Classification system. The morphological characteristics of this reference stream
are included in Table 2.
15
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.0 STREAM CHANNEL DESIGN
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Table 2. Middle Branch of Hewlett's Creek Morphology (Existing,
Design, and Reference)
Parameter Existing Reference Reference Reference Design
Reach Name Hewlett Panther Johannah Batorora Hewlett
Bankfull XSEC Area, Abkf (ft) 30 17.9 8.6 23.9 30
Bankfull Width, Wbkf (ft) 20 11.5 10.4 15.5 19
Bankfull Mean Depth, Dbkf (ft) 1.5 1.6 0.8 1.5 1.6
Width to Depth Ratio, W/D (ft/ft) 13.3 7.4 12.6 10.1 12
Entrenchment Ratio, Wfpa/Wbkf (ft/ft) 2 17.4 19.2 12.9 3
Bank Height Ratio, Dtob/Dmax (ft/ft) 2.0 1 1 1 1
Min Bkf Max Depth, Dmax (ft) 1.6 --- --- --- 2.1
Max Bkf Max Depth, Dmax (ft) 1.9 --- - -- 2.8
Min Bkf Max Depth, Dmax/Dbkf 1.1 1.6 1.3 1.4 1.3
Max Bkf Max Depth, Dmax/Dbkf 1.3 1.8
Min Meander Length, Lm (ft) 100 --- --- --- 86
Max Meander Length, Lm (ft) 280 --- --- --- 171
Min Meander len Ratio, Im/Wbkf 5 2.3 1.9 4.1 4.5
Max Meander Len Ratio, Lm/Wbkf 14 9.1 5.1 6.8 9
Min Radius of Curvature, Re (ft) 60 --- --- --- 34
Max Radius of Curvature, Rc (ft) 80 --- --- --- 49
Min Rc Ratio, RcMbkf 3 0.5 0.9 0.7 1.8
Max Rc Ratio, RcMbkf 4 1.5 2.3 2.6 2.6
Min Belt Width, Wblt (ft) 25 --- --- --- 42
Max Belt Width, Wblt (ft) 40 --- --- --- 76
Min MW Ratio, Wblt/Wbkf (ft) 1.3 1.9 1.3 2.9 2.2
Max MW Ratio, Wblt/Wbkf (ft) 2 8.7 4.4 4.5 4
Sinuosity, K 1.05 1.2 1.2 1.2 1.2
Valley Slope, Sval (ft/ft) .0026 .0040 .0026 .0061 .0026
Channel Slope, Schan=SvaVK (ft/ft) .0025 .0033 .0021 .0051 .0021
Pool Slope, Spool (ft/ft) 0 --- - - 0
Pool Slope Ratio, Spool/Schan 0 0 0 0
Min Pool Depth, Dpool (ft) 1.7 --- --- --- 2.4
Max Pool Depth, Dpool (ft) 2 --- - - 3.0
Min Pool Depth Ratio, DpooVDbkf 1.1 1.6 1.9 2 1.5
Max Pool Depth Ratio, DpooVDbkf 1.3 2
Min Pool Width, Wpool (ft) 21 --- - - 19
Max Pool Width, W pool (ft) 25 --- - - 22.8
Min Pool Wid Ratio, WpoolMbkf 1.1 1 1.2 0.9 1
Max Pool Wid Ratio, Wpool/Wbkf 1.3 1.2
Min Length Pool Spacing, Lps (ft) 40 --- - --- 57
Max Length Pool Spacing, Lps (ft) 220 --- - -- 114
Min Pool Spacing Ratio, Lps/Wbkf 2 1.3 1.2 1.7 3
Max Pool Spacing Ratio, Lps/Wbkf 11 It 3.8 3.9 6
16
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.0 STREAM CHANNEL DESIGN
This restoration will classify as a Priority 2 restoration (Rosgen, 1997). The floodplain
will be re-established to fit the existing or slightly raised stream profile. The grade of the
stream will be raised in some areas and a floodplain will be established at the new
bankfull elevation. Table 3 describes and summarizes the four priorities of incised river
restoration (Rosgen, 1997). The proposed stream restoration will restore the natural
meander pattern, modify channel cross-section restore bedform, improve sediment
transport capacity, enhance habitat, and re-establish a floodplain for the stream.
The design was based upon Dave Rosgen's natural channel design methodology. As
described in Section 3.0, reference reaches were utilized on which the morphological
characteristics were measured to determine a range of values for the stable dimension,
pattern, and profile of the proposed channel. The measured and proposed morphological
characteristic's are shown in Table 2.
A conceptual design was developed from the range of values listed in Table 2. This
stream restoration project will result in approximately 3,600 restored linear feet (as
measure from the thalweg) of The Middle Branch of Hewlett's Creek. The plan view of
the proposed restoration design can be seen in Figures 4, 5 and 6.
17
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Table 3. Priorities, Description and Summary for Incised River Restoration
DESCRIPTION METHODS ADVANTAGES DISADVANTAGES
PRIORITY 1 Re-establish channel on Re-establishment of 1) floodplain re-
Convert G and/or F previous floodplain using relic floodplain and stable establishment could cause
stream types to C and/or channel or construction of channel: flood damage to urban
E at previous elevation new bankfull discharge 1) reduces bank height and agricultural and industrial
w/floodplain channel. Design new channel streambank erosion development.
for dimension, pattern and 2) reduces land toss 2) downstream end of
profile characteristic of stable 3) raises water table project could require grade
form. Fill in existing incised 4) decreases sediment control from new to
channel or with discontinuous 5) improves aquatic and previous channel to prevent
oxbow lakes level with new terrestrial habitats head-cutting.
floodplain elevation. 6) improves land
productivity, and
7) improves aesthetics.
PRIORITY 2 If belt width provides for the 1) decreases bank height 1) does not raise water
Convert G and/or F minimum meander width ratio and streambank erosion table back to previous
stream types to C or E. for C or E stream types, 2) allows for riparian elevation
Re-establishment of construct channel in bed of vegetation to help stabilize 2) shear stress and velocity
floodplain at existing or existing channel, convert banks higher during flood due to
higher, but not at existing bed to new 3) establishes floodplain to narrower floodplain
original level floodplain. If belt width is too help take stress of channel 3) upper banks need to be
narrow, excavate streambank during flood sloped and stabilized to
walls. End-hall material or 4) improves aquatic habitat reduce erosion during
place in streambed to raise 5) prevents wide-scale flood.
bed elevation and create new flooding of original land
floodplain in the deposition. surface
6) reduces sediment
7) downstream grade
transition for grade control
is easier.
PRIORITY 3 Excavation of channel to 1) reduces the amount of 1) high cost of materials
Convert to a new stream change stream type involves land needed to return the for bed and streambank
type without an active establishing proper river to a stable form. stabilization
floodplain, but dimension, pattern and 2) developments next to 2) does not create the
containing a floodprone profile. To convert G to B river need not be re-located diversity of aquatic habitat
area. Convert G to B stream involves an increase in due to flooding potential 3) does not raise water
stream type, or F to Bc width/depth and entrenchment 3) decreases flood stage for table to previous levels.
ratio, shaping upper slopes the same magnitude flood
and stabilizing both bed and 4) improves aquatic
banks. A conversion from F habitat.
to Bc stream type involves a
decrease in width/depth ratio
and an increase in
entrenchment ratio.
PRIORITY 4 A long list of stabilization 1) excavation volumes 1) high cost for
Stabilize channel in materials and methods have reduced stabilization
place been used to decrease stream 2) land needed for 2) high risk due to
bed and bank erosion, restoration is minimal excessive shear stress and
including concrete, gabions, velocity
boulders and bio-engineering 3) limited aquatic habitat
methods depending on nature of
stabilization methods used.
Source: Rosgen, 1997, "A Geomorphological Approach to Restoration of Incised Rivers"
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Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Existing pattern measurements were taken from the topographic mapping. A stable
pattern will be established by establishing new meanders along the channel. This will be
achieved by introducing meanders into the stream with radius of curvatures and lengths
based on reference reach data and the existing constraints. The maximum stream length
and sinuosity has been designed into the new channel based on the reference data and
project constraints. Introduction of these meanders will improve habitat while lowering
slope and shear stress.
4.1.3 Bedform
The existing bedform along the Middle Branch of Hewlett's Creek is in poor condition.
Long, straight sections of the channel consist of predominantly run bedform features. The
design channel will incorporate ripples and pools to provide bedform common to E5
stream types. Pools will be located in the outside of meander bends with riffles in the
inflection points between meanders. The ripples will have a thalweg depth of 1.6 feet
while the pools will be deeper with a maximum depth of 3.0 feet. A graph of the
proposed profile can be seen in Figure 8. The profile may be adjusted slightly during the
final design phase of the project.
Cross-vanes will be utilized as grade control structures and to tie the relocated sections
back into the existing channel. The cross vanes will be constructed out of natural
materials such as wood and some boulders.
The existing pool-to-pool spacing is impaired in areas due to tight meander geometry.
The proposed spacing is 57 to 114 feet, which is within the range of 3 and 6 bankfull
widths as determined from the reference reach data. To accomplish this, pools will be
realigned or constructed such that they will be located in the outside of the meander
bends. Bedform will also be addressed through the strategic placement of natural material
structures such as cross vanes, root wads and large woody debris. Modifications to the
bedform will provide stability and habitat to the channel.
4.1.4 Riparian Areas
A riparian zone will be created around the new proposed stream channel to enhance both
aquatic and terrestrial habitat as well as stabilize the stream channel. The riparian zone
will extend at least 15 feet on either side of the channel from the top of bank. Were ever
possible the riparian zone will extend at least 25 feet on either side of the channel. These
areas will be planted with appropriate riparian vegetation as described in Section 6.0
Habitat Restoration. The riparian zone is limited by the urban constraints and the
constraints of an active golf course that includes play that cross the stream channel.
23
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Figure. 7: Typical Cross-Sections
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Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.2 SEDIMENT TRANSPORT
A stable stream has the capacity to move its sediment load without aggrading or
degrading. The total load of sediment can be divided into bed load and wash load. Wash
load is normally composed of fine sands, silts and clay and transported in suspension at a
rate that is determined by availability and not hydraulically controlled. Bed load is
transported by rolling, sliding, or hopping (saltating) along the bed. At higher discharges,
some portion of the bed load can be suspended, especially if there is a sand component in
the bed load. Bed material transport rates are essentially controlled by the size and nature
of the bed material and hydraulic conditions (Hey 1997).
Critical dimensionless shear stress can be found using Shield's Curve and surface particle
sample from a representative riffle in the reach. A riffle bed surface pebble count was
taken at a riffle on the Middle Branch of Hewlett's Creek. The riffle bed surface d50 was
then calculated to be 0.06 mm. The shear stress placed on the sediment particles is the
force that entrains and moves the particles, in a given channel geometry. From Shields
curve the shear stress that entrains and moves particles in this stream based on the d50 is
.0025 lbs/sqft.
Wetted perimeter was measured off of a CADD file of the typical riffle cross-section
drawn to scale. The wetted perimeter was measured to be 29 ft, while the cross-sectional
area was 30 sqft this produced a hydraulic radius of 1.03. The Slope for the used for the
shear stress calculation is 0.0023. The resultant shear stress for the proposed channel is
0.15 lbs/sgft, this shear stress is sufficient to move the d84 of the riffle bed material,
which is 0.15 mm. Shield's Curve predicts that this stream can move a particle that is, on
average, greater than 5 mm. Since the D84 was 0.15 mm and Shield's Curve predicts 5
mm, the proposed stream has the competency to move its bed load.
Sediment transport analysis was examined at the restoration site through the comparison
of existing and post restoration shear stress analysis. The existing channel does not
appear to be aggrading so it is implied that it is more capable of transporting its
watershed sediment load. Two existing shear stresses are examined and one restored
shear stress. Shear stress is approximated using the equation shear stress = density of
water times the hydraulic radius times the average water surface slope. Existing bankfull
shear stress is 0.233 lbs/sgft. The top of bank shear stress is 0.4541bs/sqft.
Post restoration, average water surface slope will be decreased and the floodplain will be
established adjacent to the bankfull channel thus lowering the top of bank shear stress
significantly. The post restoration bankfull shear and top of bank shear stress is 0.222
lbs/sgft. These calculations were confirmed with HEC-RAS modeling.
4.3 FLOODING ANALYSIS
This restoration site is not in a mapped FEMA regulatory floodway zone and therefore, is
not subject to FEMA regulations. NCSU design team has also received verification from
26
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
the City of Wilmington Division of Stormwater that this reach of Hewlett's Creek is not
FEMA mapped and does not have a recorded history of flood related incidents. Currently
there are no structures located in the adjacent areas that would be impacted by floodplain
alterations. The Priority 2 restoration of the stream will leave the stream's existing profile
elevations essentially the same. A new floodplain will be established so that the active
stream will be able to access it during larger storm events. Considering the type of
restoration it is assumed that for smaller events the water surface elevations along the
stream shall remain the same. During storms where the stream accesses the newly
establishment floodplain the new water surface elevations are expected to be lower than
the existing water surface elevations of storms of the same magnitude. The restoration
will create neither positive nor negative water surface elevation changes during the larger
storm events (greater than 25-year). HEC-RAS was used to analyze both existing and
proposed conditions after the design was finalized. Sheer stress and flood stages were
compared at various return intervals to evaluate the design.
4.4 STRUCTURES
Several different structures made of natural materials will be installed along the Middle
Branch of Hewlett's Creek. These structures include cross vanes, single vanes, and root
wads. Natural materials such rocks and root wads will be used to create these structures
from off-site sources and on-site sources.
4.4.1 Cross Vane
A cross vane structure serves to maintain the grade of the stream. The design shape is
roughly that of the letter "U" with the apex located on the upstream side at the foot of the
riffle. Footer rocks are placed in the channel bottom for stability. Rocks or logs are then
placed on these footer rocks in the middle of the channel at approximately the same
elevation as the ripple. On either side of the channel, rocks or logs are placed at an angle
to the stream bank, gradually inclining in elevation until they are located above the
bankfull surface directly adjacent to the stream bank. Water flowing downstream is
directed over the vane towards the middle of the channel. Rocks or a log placed at the
apex determine the bed elevation upstream. A cross vane is primarily used for grade
control and to protect the stream banks.
4.4.2 Root Wads
The objectives of these structure placements are as follows: (1) protect the stream bank
from erosion; (2) provide in-stream and overhead cover for fish; (3) provide shade,
detritus, terrestrial insect habitat: (4) look natural, and (5) provide diversity of habitats
(Rosgen 1996). A footer log and boulder are placed on the channel bottom abutting the
stream bank along an outside meander that will provide support for the root wad and
additional stability to the bank. A large tree root wad is then placed on the stream bank
with additional boulders and rocks on either side for stability. Flowing water is deflected
away from the bank and towards the center of the channel.
27
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.4.3 Single Vane
A single vane structure serves to maintain the pattern of the stream. Footer rocks are
placed in the channel bottom for stability. Rocks or logs are then placed on these footer
rocks in the middle of the channel at approximately the same elevation as the ripple. On
either side of the channel, rocks or log is placed at an angle to the stream bank, gradually
inclining in elevation until they are located above the bankfull surface directly adjacent to
the stream bank. Water flowing downstream is directed over the vane towards the middle
of the channel. A single vane is primarily used to turn the stream flow and control and to
protect the stream banks.
Specific location of these structures will be determined during final design.
28
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
5.0 HABITAT RESTORATION
The restoration plan requires the establishment of riparian vegetation at the site. The
proposed vegetation is described in the following sections.
5.1 VEGETATION
Vegetation that develops a quick canopy, has an extensive root system, and a substantial
above-ground plant structure is needed to help stabilize the banks of a restored stream
channel in order to reduce scour and runoff erosion. In natural riparian environments,
pioneer plants that often provide these functions are alder, river birch, silky dogwood,
and willow. Once established, these trees and shrubs create an environment that allows
for the succession of the other riparian species including ashes, black walnuts, red
maples, sycamores, oaks, and other riparian species.
In the newly restored stream channel, revegetation will be vital to help stabilize the
stream banks and establish a riparian zone around the restored channel. Revegetation
efforts on this project will emulate natural vegetation communities found along relatively
undisturbed stream corridors. To quickly establish dense root mass along the channel
bank, a native grass mixture will be planted on the streambed and bank. Shrubs will be
utilized on the stream bank and along the floodplain to provide additional root mass.
Extra care will be given to the outside of the meander bends to ensure a dense root mass
in those areas of high stress. Coir matting or similar material will be used to provide
erosion protection until vegetation can be established. Along the tops of the channel
banks, trees, shrubs and a native grass mixture will be planted.
A mixture of seeds, live stakes, bare root, as well as balled in burlap nursery stock, some
2 "- 4" caliper tree and transplants will be used to stabilize the banks. Proposed species
to be planted included, but are not limited to:
Trees
Blackcherry (Prunus serotina)
Blackgum (Nyssa sylvatica)
Loblolly Bay (Gordonia lasianthus)
River Birch (Betula nigra)
Sugarberry (Celtis laevigata)
Shrubs
American hornbeam (Carpinus caroliniana)
Fetter bush (Lyonia lucida)
Inkberry (Ilex glabra)
Marsh mallow (Hibiscus moscheutos)
Silky dogwood (Corpus amomum)
Sweet pepperbush (Clethra alnifolia)
Virginia willow (Itea virginica)
29
I .
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Herbs- Permanent seed mixture
Deertongue (Panicum clandestinum)
Purple love grass (Ergrostis spectabilis)
Switch Grass (Panicuin virgatum)
Tussock sedge (Carex stricta)
Other herbaceous vegetation
Dwarf spike-rush (Eleocharis parvula)
Ironweed (Vernonia noveboracensis)
Jack-in-the-pulpit (Arisaema triphyllum)
Woody vegetation will be planted between February and May to allow plants to stabilize
during the dormant period and set root during the spring season. In the areas where
invasive and exotic species are located, during construction and monitoring control by
removal or appropriate herbicides will be implemented to prevent competition with the
revegetation efforts.
5.2 RIPARIAN BUFFERS
At least three different types of riparian buffers will be employed to vegetate the restored
channel. All buffers will use plants native to the coastal plain region of North Carolina.
In areas where the fairways cross the stream channel, vegetation will be kept to a minimal
height so as not to obstruct views and play within the crossing. The areas along the city
sewer line (within approximately 10' to either side of the utility) will be planted with
vegetation having shallow (limited) root structure so that the sewer line and access to it
shall not be impacted or impeded. The remaining areas will be planted with native trees,
shrubs, grasses and other herbaceous vegetation in order to restore natural coastal plain
plant communities. Proposed species to be planted include but are not limited to those
listed in the above section
5.2.1 Temporary Seeding
A temporary seed mixture will be applied to all disturbed areas immediately after
construction activities have completed. This temporary seed mixture will provide erosion
control until permanent seed can become established. Permanent seed will be native to
the coastal region of North Carolina.
30

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
6.0 MONITORING
6.1 STREAM CHANNEL
Monitoring of the stability of the channel is recommended to occur approximately 6
months after restoration is complete or after bankfull (or greater) events and should
continue annually for a period of 3 to 5 years. Monitoring practices may include, but are
not limited to, installing bank erosion pins and a toe pin, monumented cross-sections,
scour chains, macroinvertebrate studies, longitudinal profiles, conducting the bank
erosion hazard rating guide and establishing photo reference points. The purpose of
monitoring is to determine bank stability, bed stability, morphological stability and
overall channel stability. Table 4, below, can be used for selecting practices.
Table 3. - Stream Monitoring Practices
PRACTICE STABILITY ASSESSMENT
Bank Erosion Pins with Toe Pin -Lateral or bank stability
Monumented Cross-Section -Vertical or bank stability
-Lateral or bank stability
Scour Chains -Vertical or bed stability
-Scour depth fora articular storm
Scour Chain w/ Monumented
Cross-Section -Vertical or bed stability
-Sediment transport relations
-Biological interpretations
Longitudinal Profile -Channel profile stability
Bank Erosion Hazard Guide -Bank erosion potential
Photo Reference Points -Overall channel stability
Macroinvertebrate -Biological indication of water quality
6.2 VEGETATION
Prior to planting, the site will be inspected and checked for proper elevation and
suitability of soils. Availability of acceptable, good quality plant species will be
determined. The site will be inspected at completion of planting to determine proper
planting methods, including proper plant spacing, density, and species composition.
Competition control will be implemented if determined to be necessary during the early
stages of growth and development of the tree species. Quantitative sampling of the
vegetation will be performed between August 1 and November 30 at the end of the first
year and after each growing season until the vegetation criteria is met.
In preparation for the quantitative sampling, 50 by 50 feet (0.05-acre) vegetative plots
will be established in the reforested area. Plots will be evenly distributed throughout the
31
I
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
site. For each plot, species composition and density will be reported. Photo points will be
taken within each zone. Monitoring will take place once each year for five years.
Success will be determined by survival of target species within the sample plots. At least
six different representative tree species should be present on the entire site. If the
vegetative success criteria are not met, the cause of failure will be determined and
appropriate corrective action will be taken.
6.3 MACROIN VERTEBRATES
A monitoring period of 3 to 5 years is commonly suggested to determine changes in
macroinvertebrate populations within a newly restored stream. The North Carolina
Wetlands Restoration Program will determine a macroinvertebrate monitoring policy.
32

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
7.0 REFERENCES
Amoroso, J.L., ed. 1999. Natural Heritage Program List of the Rare Plait Species of
North Carolina. North Carolina Natural Heritage Program, Division of Parks and
Recreation, North Carolina Department of Environment and Natural Resources. Raleigh,
North Carolina.
Cowardin, L.M., V. Carter, F.C. Golet and E.T. LaRoe. 1979. Classification of Wetlands and
Deepwater Habitats of the United States. U.S. Fish and Wildlife Service, Office of
Biological Services, FWS/OBS-79/3 I. U.S. Department of the Interior, Washington, DC.
Choate, J.R., J.K. Jones, Jr., and C. Jones. 1994. Handbook of Mammals of the South-Central
States. Louisiana State University Press, Baton Rouge, Louisiana.
Doll, B. A., et al. 2000. Hydraulic Geometry Relationships for Urban Streams throughout the
Piedmont of North Carolina. American Water Resources Association.
Godfrey, R.K., and J.W. Wooten. 1979. Aquatic and Wetland Plants of Southeastern United States.
Monocotyledons. The University of Georgia Press, Athens, Georgia.
Godfrey, R.K., and J.W. Wooten. 1981. Aquatic and Wetland Plants of Southeastern United States.
Dicotyledons. The University of Georgia Press, Athens, Georgia.
Harrelson, Cheryl, C.L. Rawlins and John Potyondy. 1994. Stream Channel Reference Sites: An
Illustrated Guide to Field Technique. United States Department of Agriculture, Forest Service.
General Technical Report RM-245.
Hey, Richard and Dave Rosgen. 1997. Fluvial Geomorphology for Engineers. Wildland Hydrology,
Pagosa Springs, Colorado.
LeGrand, H.E., Jr. and S.P. Hall, eds. 1999. Natural Heritage Program List of the Rare
Animal Species of North Carolina. North Carolina Natural Heritage Program, Division of
Parks and Recreation, North Carolina Department of Environment and Natural
Resources. Raleigh, North Carolina.
NCDENR. "Water Quality Stream Classifications for Streams in North Carolina." Water Quality
Section. http:/Ih2o.enr.state.nc.us/wghome.htmi (16 July 2001).
Radford, A.E., H.E. Ahles and G.R. Bell. 1968. Manual of the Vascular Flora of the Carolinas. The
University of North Carolina Press, Chapel Hill, North Carolina.
Rosgen, Dave. 1997. A Geomorphological Approach to Restoration of Incised Rivers.
Wildland Hydrology. Proceedings of the Conference on Management of Landscapes
Disturbed by Channel Incision.
33

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Schafale, M. P. and A. S. Weakley. 1990. Classification of the Natural Communities of
North Carolina: Third Approximation. North Carolina Natural Heritage Program.
Raleigh, North Carolina
United States Department of Agriculture - Soil Conservation Service. December, 1977. "Soil
Survey of Guilford County, North Carolina." US Government Printing Office, Washington,
DC.
United States Fish and Wildlife Service. "Region 4, Southeast Region/Endangered Species." North
Carolina Ecological Services. http://nc-es.fws.gov/ (August 2001).
USDA, NRCS. 2001. The PLANTS Database, Version 3.1 (http://plants.usda.gov). National Plant
Data Center, Baton Rouge, LA 70874-4490 USA.
34
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.2.5 Wildlife Observations
Wildlife and signs of wildlife were noted during on-site visits, however, a formal wildlife
survey was not performed. Tracks of white tailed deer (Odocoileus virgin ianus) and
raccoon (Procyon lotor) were observed along the stream banks. A variety of birds were
observed in the thickets and shrubs surrounding the stream channel and forest, including:
various sparrows.
2.2.5.1 Possible Invasive Wildlife
The following species were identified during site visits to the Middle Branch of Hewlett's
Creek; Asian tiger mosquito (Aedes albopictus), Bullfrog (Rana catesbeiana) (auditory
identification), European gypsy moth (Lymantria dispar), and European starling (Stunius
vulgaris). The bullfrog is listed based on auditory identification by one of the project
researchers. The gypsy moth is listed based on visual identification of nests. The
mosquito and starling are listed due to their ubiquitous nature.
2.2.6 Endangered Species
The NCSU design team has not identified endangered plant or animal species or any such
habitat that would support the endangered species listed in this section. The NCSU
design team has made multiple visits to the Pine Valley Country Club and the restoration
site. Below is a list obtained from Natural Heritage, of the endangered of concern for
New Hanover County.
2.2.6.1 Endangered Flora
Vascular Plants:
Cooley's meadowrue
Rough-leaved loosestrife
Seabeach amaranth
Bog St. John's-wort
Carolina asphodel
Carolina bishopweed
Carolina beaksedge
Chapman's sedge
Coastal golden rod
"Dune bluecurls"
Pickering's dawnflower
Pondspice
Sandhills milkvetch
Savanna indigo-bush
Spiked medusa
Spring-flowering goldenrod
Tough bumelia
Endangered
Endangered
Threatened
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
12
CITY OF WILMINGTON STORMWATER POND
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1.) Area shall be graded smooth upon completion of earthwork activities, with a
slope toward the storm water pond and a maximum side slope of 3:1
2.) Area shall be stabilized with temporary seed upon completion of earthwork
3.) Area shall be sprigged with Bermuda grass variety between May 15th and
June 15th, the contractor shall coordinate with the golf course superintendent
LEGEND
CROSS VANE * CART PATH
*
-

-See M.1 13 (C-8) Sr. 'eDela6 16 C-8)
LOG VANE * CULVERT CROSSING

-See Deta 11 C-8 -See Delai 7 C-7
ROOT WADS * RETAINING WALL

•S- Detal 12 (C-8) 'See Dalai 16 C-9
NOTE: Structure placement on Plan Sheets
ore for location only. Actual placement shall
be directed by Resident Engineer
DETAL
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CURVE TABLE
LINE TABLE
CURVE I
LENGTH
RADIUS
C_ 1
59.6
39.3
C— 2
223
320
C_ 3
49.8
34.0
C_ 4
25.0
34.0
C_ 5
433
39.0
C— 5
721
420
C— 7
68.1
330
C- 81
69.2
420
C— 93899
161780
36.0
C— 10
29.0
40.0
C- 11
58.7
430
C— 12
437
350
C- 13
36.8
310
C— 14
36.1
34.0
NOTE: The listed Radius of Curvatures are
measured from the stream centerline.
Actual Radius of Curvatures maybe
adjusted by Resident NCSU Engineer
CLAY PLUG
SEE DETAIL 9 (C-7)
I
I
STREAM (SREV)
CLAr PWG
SEE DETAIL 9 (C-7)
NOTE: The listed Northing and Easting Columns
represent the head of the appropriate riffle section
along the centerline of the stream. Actual riffle
starting locations, bearing and lengths maybe adjusted
by Resident NCSU Engineer
----
1 -
BETWEEN STA: 18+40 TO TA:19+61
THE CHANNEL WILL NOT BE REALIGNED
LEGEND
LINE TABLE
CART PATH—*
r xp � • .%
UNE
LENGTH BEARING
NORTHING
EASTING
L— 1
23.3
161485
2332861
L— 2
31.9
151518
2332892
L— 3
31.9 N1
151354
2332951
L— 4
519
161607
2332952
5
38.5
161691
2332963
L— 6
19.4
161780
2332973
L— 71
37.5 •W
161832
2333028
L_ aA4N,
161914
2333034
L— 9161927
2333125
L— 10161972
2333159
L_ 11162066
2333276
L— 12162150
2333293
L— 13162192
2333344
L— 14
1022461
2333357
NOTE: The listed Northing and Easting Columns
represent the head of the appropriate riffle section
along the centerline of the stream. Actual riffle
starting locations, bearing and lengths maybe adjusted
by Resident NCSU Engineer
----
1 -
BETWEEN STA: 18+40 TO TA:19+61
THE CHANNEL WILL NOT BE REALIGNED
LEGEND
CROSS VANE *
CART PATH—*
r xp � • .%
21SEE
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See Deta9 15 C-8)
LOG VANE *
CULVERT CROSSING
0
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•See Deta9 7 (C-7)
ROOT WADS *
RETAINING WALL
Cur PLUG
It
SEE DETAIL 9 (C-7)
•See DetoR 12 (C -a)
Detail 16 C-9)
NOTE: Structure placement on Plan Sheets
are for location only. Actual placement shall
be directed by Resident Engineer
DETAIL
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measured from the stream centerline. represent the heod of the appropriate riffle section
Actual Radius of Curvatures maybe along the centerline of the stream. Actual riffle
adjusted by Resident NCSU Engineer starting locations, bearing and lengths maybe adjusted
by Resident NCSU Engineer
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Existing pattern measurements were taken from the topographic mapping. A stable
pattern will be established by establishing new meanders along the channel. This will be
achieved by introducing meanders into the stream with radius of curvatures and lengths
based on reference reach data and the existing constraints. The maximum stream length
and sinuosity has been designed into the new channel based on the reference data and
project constraints. Introduction of these meanders will improve habitat while lowering
slope and shear stress.
4.1.3 Bedform
The existing bedform along the Middle Branch of Hewlett's Creek is in poor condition.
Long, straight sections of the channel consist of predominantly run bedform features. The
design channel will incorporate ripples and pools to provide bedform common to E5
stream types. Pools will be located in the outside of meander bends with riffles in the
inflection points between meanders. The ripples will have a thalweg depth of 1.6 feet
while the pools will be deeper with a maximum depth of 3.0 feet. A graph of the
proposed profile can be seen in Figure 8. The profile may be adjusted slightly during the
final design phase of the project.
Cross-vanes will be utilized as grade control structures and to tie the relocated sections
back into the existing channel. The cross vanes will be constructed out of natural
materials such as wood and some boulders.
The existing pool-to-pool spacing is impaired in areas due to tight meander geometry.
The proposed spacing is 57 to 114 feet, which is within the range of 3 and 6 bankfull
widths as determined from the reference reach data. To accomplish this, pools will be
realigned or constructed such that they will be located in the outside of the meander
bends. Bedform will also be addressed through the strategic placement of natural material
structures such as cross vanes, root wads and large woody debris. Modifications to the
bedform will provide stability and habitat to the channel.
4.1.4 Riparian Areas
A riparian zone will be created around the new proposed stream channel to enhance both
aquatic and terrestrial habitat as well as stabilize the stream channel. The riparian zone
will extend at least 15 feet on either side of the channel from the top of bank. Were ever
possible the riparian zone will extend at least 25 feet on either side of the channel. These
areas will be planted with appropriate riparian vegetation as described in Section 6.0
Habitat Restoration. The riparian zone is limited by the urban constraints and the
constraints of an active golf course that includes play that cross the stream channel.
23
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Figure 7: Typical Cross-Sections
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Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.2 SEDIMENT TRANSPORT
A stable stream has the capacity to move its sediment load without aggrading or
degrading. The total load of sediment can be divided into bed load and wash load. Wash
load is normally composed of fine sands, silts and clay and transported in suspension at a
rate that is determined by availability and not hydraulically controlled. Bed load is
transported by rolling, sliding, or hopping (saltating) along the bed. At higher discharges,
some portion of the bed load can be suspended, especially if there is a sand component in
the bed load. Bed material transport rates are essentially controlled by the size and nature
of the bed material and hydraulic conditions (Hey 1997).
Critical dimensionless shear stress can be found using Shield's Curve and surface particle
sample from a representative riffle in the reach. A riffle bed surface pebble count was
taken at a riffle on the Middle Branch of Hewlett's Creek. The riffle bed surface d50 was
then calculated to be 0.06 mm. The shear stress placed on the sediment particles is the
force that entrains and moves the particles, in a given channel geometry. From Shields
curve the shear stress that entrains and moves particles in this stream based on the d50 is
.0025 lbs/sqft.
Wetted perimeter was measured off of a CADD file of the typical riffle cross-section
drawn to scale. The wetted perimeter was measured to be 29 ft, while the cross-sectional
area was 30 sqft this produced a hydraulic radius of 1.03. The Slope for the used for the
shear stress calculation is 0.0023. The resultant shear stress for the proposed channel is
0.15 lbs/sgft, this shear stress is sufficient to move the d84 of the riffle bed material,
which is 0.15 mm. Shield's Curve predicts that this stream can move a particle that is, on
average, greater than 5 mm. Since the D84 was 0.15 mm and Shield's Curve predicts 5
mm, the proposed stream has the competency to move its bed load.
Sediment transport analysis was examined at the restoration site through the comparison
of existing and post restoration shear stress analysis. The existing channel does not
appear to be aggrading so it is implied that it is more capable of transporting its
watershed sediment load. Two existing shear stresses are examined and one restored
shear stress. Shear stress is approximated using the equation shear stress = density of
water times the hydraulic radius times the average water surface slope. Existing bankfull
shear stress is 0.2331bs/sqft. The top of bank shear stress is 0.454 lbs/sqft.
Post restoration, average water surface slope will be decreased and the floodplain will be
established adjacent to the bankfull channel thus lowering the top of bank shear stress
significantly. The post restoration bankfull shear and top of bank shear stress is 0.222
lbs/sgft. These calculations were confirmed with HEC-RAS modeling.
4.3 FLOODING ANALYSIS
This restoration site is not in a mapped FEMA regulatory floodway zone and therefore, is
not subject to FEMA regulations. NCSU design team has also received verification from
26
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
the City of Wilmington Division of Stormwater that this reach of Hewlett's Creek is not
FEMA mapped and does not have a recorded history of flood related incidents. Currently
there are no structures located in the adjacent areas that would be impacted by floodplain
alterations. The Priority 2 restoration of the stream will leave the stream's existing profile
elevations essentially the same. A new floodplain will be established so that the active
stream will be able to access it during larger storm events. Considering the type of
restoration it is assumed that for smaller events the water surface elevations along the
stream shall remain the same. During storms where the stream accesses the newly
establishment floodplain the new water surface elevations are expected to be lower than
the existing water surface elevations of storms of the same magnitude. The restoration
will create neither positive nor negative water surface elevation changes during the larger
storm events (greater than 25-year). HEC-RAS was used to analyze both existing and
proposed conditions after the design was finalized. Sheer stress and flood stages were
compared at various return intervals to evaluate the design.
4.4 STRUCTURES
Several different structures made of natural materials will be installed along the Middle
Branch of Hewlett's Creek. These structures include cross vanes, single vanes, and root
wads. Natural materials such rocks and root wads will be used to create these structures
from off-site sources and on-site sources.
4.4.1 Cross Vane
A cross vane structure serves to maintain the grade of the stream. The design shape is
roughly that of the letter "U" with the apex located on the upstream side at the foot of the
riffle. Footer rocks are placed in the channel bottom for stability. Rocks or logs are then
placed on these footer rocks in the middle of the channel at approximately the same
elevation as the ripple. On either side of the channel, rocks or logs are placed at an angle
to the stream bank, gradually inclining in elevation until they are located above the
bankfull surface directly adjacent to the stream bank. Water flowing downstream is
directed over the vane towards the middle of the channel. Rocks or a log placed at the
apex determine the bed elevation upstream. A cross vane is primarily used for grade
control and to protect the stream banks.
4.4.2 Root Wads
The objectives of these structure placements are as follows: (1) protect the stream bank
from erosion; (2) provide in-stream and overhead cover for fish; (3) provide shade,
detritus, terrestrial insect habitat: (4) look natural, and (5) provide diversity of habitats
(Rosgen 1996). A footer log and boulder are placed on the channel bottom abutting the
stream bank along an outside meander that will provide support for the root wad and
additional stability to the bank. A large tree root wad is then placed on the stream bank
with additional boulders and rocks on either side for stability. Flowing water is deflected
away from the bank and towards the center of the channel.
27
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.4.3 Single Vane
A single vane structure serves to maintain the pattern of the stream. Footer rocks are
placed in the channel bottom for stability. Rocks or logs are then placed on these footer
rocks in the middle of the channel at approximately the same elevation as the ripple. On
either side of the channel, rocks or log is placed at an angle to the stream bank, gradually
inclining in elevation until they are located above the bankfull surface directly adjacent to
the stream bank. Water flowing downstream is directed over the vane towards the middle
of the channel. A single vane is primarily used to turn the stream flow and control and to
protect the stream banks.
Specific location of these structures will be determined during final design.
28
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
5.0 HABITAT RESTORATION
The restoration plan requires the establishment of riparian vegetation at the site. The
proposed vegetation is described in the following sections.
5.1 VEGETATION
Vegetation that develops a quick canopy, has an extensive root system, and a substantial
above-ground plant structure is needed to help stabilize the banks of a restored stream
channel in order to reduce scour and runoff erosion. In natural riparian environments,
pioneer plants that often provide these functions are alder, river birch, silky dogwood,
and willow. Once established, these trees and shrubs create an environment that allows
for the succession of the other riparian species including ashes, black walnuts, red
maples, sycamores, oaks, and other riparian species.
In the newly restored stream channel, revegetation will be vital to help stabilize the
stream banks and establish a riparian zone around the restored channel. Revegetation
efforts on this project will emulate natural vegetation communities found along relatively
undisturbed stream corridors. To quickly establish dense root mass along the channel
bank, a native grass mixture will be planted on the streambed and bank. Shrubs will be
utilized on the stream bank and along the floodplain to provide additional root mass.
Extra care will be given to the outside of the meander bends to ensure a dense root mass
in those areas of high stress. Coir matting or similar material will be used to provide
erosion protection until vegetation can be established. Along the tops of the channel
banks, trees, shrubs and a native grass mixture will be planted.
A mixture of seeds, live stakes, bare root, as well as balled in burlap nursery stock, some
2 "- 4" caliper tree and transplants will be used to stabilize the banks. Proposed species
to be planted included, but are not limited to:
Trees
Blackcherry (Prunus serotina)
Blackgum (Nyssa sylvatica)
Loblolly Bay (Gordonia lasianthus)
River Birch (Betula nigra)
Sugarberry (Celtis laevigata)
Shrubs
American hornbeam (Carpinus caroliniana)
Fetter bush (Lyonia lucida)
Inkberry (Ilex glabra)
Marsh mallow (Hibiscus moscheutos)
Silky dogwood (Corpus amomum)
Sweet pepperbush (Clethra alnifolia)
Virginia willow (Itea virginica)
29

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Herbs- Permanent seed mixture
Deertongue (Panicum clandestinuin)
Purple love grass (Ergrostis spectabilis)
Switch Grass (Panicum virgatum)
Tussock sedge (Carex stricta)
Other herbaceous vegetation
Dwarf spike-rush (Eleocharis parvula)
Ironweed (Vernonia noveboracensis)
Jack-in-the-pulpit (Arisaema triphyllum)
Woody vegetation will be planted between February and May to allow plants to stabilize
during the dormant period and set root during the spring season. In the areas where
invasive and exotic species are located, during construction and monitoring control by
removal or appropriate herbicides will be implemented to prevent competition with the
revegetation efforts.
5.2 RIPARIAN BUFFERS
At least three different types of riparian buffers will be employed to vegetate the restored
channel. All buffers will use plants native to the coastal plain region of North Carolina.
In areas where the fairways cross the stream channel, vegetation will be kept to a minimal
height so as not to obstruct views and play within the crossing. The areas along the city
sewer line (within approximately 10' to either side of the utility) will be planted with
vegetation having shallow (limited) root structure so that the sewer line and access to it
shall not be impacted or impeded. The remaining areas will be planted with native trees,
shrubs, grasses and other herbaceous vegetation in order to restore natural coastal plain
plant communities. Proposed species to be planted include but are not limited to those
listed in the above section
5.2.1 Temporary Seeding
A temporary seed mixture will be applied to all disturbed areas immediately after
construction activities have completed. This temporary seed mixture will provide erosion
control until permanent seed can become established. Permanent seed will be native to
the coastal region of North Carolina.
30

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
6.0 MONITORING
6.1 STREAM CHANNEL
Monitoring of the stability of the channel is recommended to occur approximately 6
months after restoration is complete or after bankfull (or greater) events and should
continue annually for a period of 3 to 5 years. Monitoring practices may include, but are
not limited to, installing bank erosion pins and a toe pin, monumented cross-sections,
scour chains, macroinvertebrate studies, longitudinal profiles, conducting the bank
erosion hazard rating guide and establishing photo reference points. The purpose of
monitoring is to determine bank stability, bed stability, morphological stability and
overall channel stability. Table 4, below, can be used for selecting practices.
Table 3. Stream Monitoring Practices
PRACTICE STABILITY ASSESSMENT
Bank Erosion Pins with Toe Pin -Lateral or bank stability
Monumented Cross-Section -Vertical or bank stability
-Lateral or bank stability
Scour Chains -Vertical or bed stability
-Scour depth fora articular storm
Scour Chain w/ Monumented
Cross-Section -Vertical or bed stability
-Sediment transport relations
-Biological interpretations
Longitudinal Profile -Channel profile stability
Bank Erosion Hazard Guide -Bank erosion potential
Photo Reference Points -Overall channel stability
Macroinvertebrate -Biological indication of water quality
6.2 VEGETATION
Prior to planting, the site will be inspected and checked for proper elevation and
suitability of soils. Availability of acceptable, good quality plant species will be
determined. The site will be inspected at completion of planting to determine proper
planting methods, including proper plant spacing, density, and species composition.
Competition control will be implemented if determined to be necessary during the early
stages of growth and development of the tree species. Quantitative sampling of the
vegetation will be performed between August 1 and November 30 at the end of the first
year and after each growing season until the vegetation criteria is met.
In preparation for the quantitative sampling, 50 by 50 feet (0.05-acre) vegetative plots
will be established in the reforested area. Plots will be evenly distributed throughout the
31
ti .
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
site. For each plot, species composition and density will be reported. Photo points will be
taken within each zone. Monitoring will take place once each year for five years.
Success will be determined by survival of target species within the sample plots. At least
six different representative tree species should be present on the entire site. If the
vegetative success criteria are not met, the cause of failure will be determined and
appropriate corrective action will be taken.
6.3 MACROIN VERTEBRATES
A monitoring period of 3 to 5 years is commonly suggested to determine changes in
macroinvertebrate populations within a newly restored stream. The North Carolina
Wetlands Restoration Program will determine a macroinvertebrate monitoring policy.
32
( 1 )
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
7.0 REFERENCES
Amoroso, J.L., ed. 1999. Natural Heritage Program List of the Rare Plant Species of
North Carolina. North Carolina Natural Heritage Program, Division of Parks and
Recreation, North Carolina Department of Environment and Natural Resources. Raleigh,
North Carolina.
Cowardin, L.M., V. Carter, F.C. Golet and E.T. LaRoe. 1979. Classification of Wetlands and
Deepwater Habitats of the United States. U.S. Fish and Wildlife Service, Office of
Biological Services, FWS/OBS-79/3 I. U.S. Department of the Interior, Washington, DC.
Choate, J.R., J.K. Jones, Jr., and C. Jones. 1994. Handbook of Mammals of the South-Central
States. Louisiana State University Press, Baton Rouge, Louisiana.
Doll, B. A., et al. 2000. Hydraulic Geometry Relationships for Urban Streams throughout the
Piedmont of North Carolina. American Water Resources Association.
Godfrey, R.K., and J.W. Wooten. 1979. Aquatic and Wetland Plants of Southeastern United States.
Monocotyledons. The University of Georgia Press, Athens, Georgia.
Godfrey, R.K., and J.W. Wooten. 1981. Aquatic and Wetland Plants of Southeastern United States.
Dicotyledons. The University of Georgia Press, Athens, Georgia.
Harrelson, Cheryl, C.L. Rawlins and John Potyondy. 1994. Stream Channel Reference Sites: An
Illustrated Guide to Field Technique. United States Department of Agriculture, Forest Service.
General Technical Report RM-245.
Hey, Richard and Dave Rosgen. 1997. Fluvial Geomorphology for Engineers. Wildland Hydrology,
Pagosa Springs, Colorado.
LeGrand, H.E., Jr. and S.P. Hall, eds. 1999. Natural Heritage Program List of the Rare
Animal Species of North Carolina. North Carolina Natural Heritage Program, Division of
Parks and Recreation, North Carolina Department of Environment and Natural
Resources. Raleigh, North Carolina.
NCDENR. "Water Quality Stream Classifications for Streams in North Carolina." Water Quality
Section. http:/lh2o.enr.state.nc.us/wghome.htmi (16 July 2001).
Radford, A.E., H.E. Ahles and G.R. Bell. 1968. Manual of the Vascular Flora of the Carolinas. The
University of North Carolina Press, Chapel Hill, North Carolina.
Rosgen, Dave. 1997. A Geomorphological Approach to Restoration of Incised Rivers.
Wildland Hydrology. Proceedings of the Conference on Management of Landscapes
Disturbed by Channel Incision.
33
4 ( ? •
. 1
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Schafale, M. P. and A. S. Weakley. 1990. Classification of the Natural Communities of
North Carolina: Third Approximation. North Carolina Natural Heritage Program.
Raleigh, North Carolina
United States Department of Agriculture - Soil Conservation Service. December, 1977. "Soil
Survey of Guilford County, North Carolina." US Government Printing Office, Washington,
DC.
United States Fish and Wildlife Service. "Region 4, Southeast Region/Endangered Species." North
Carolina Ecological Services. http://nc-es.fws.gov/ (August 2001).
USDA, NRCS. 2001. The PLANTS Database, Version 3.1 (http://plants.usda.gov). National Plant
Data Center, Baton Rouge, LA 70874-4490 USA.
34
",.
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.2.5 Wildlife Observations
Wildlife and signs of wildlife were noted during on-site visits, however, a formal wildlife
survey was not performed. Tracks of white tailed deer (Odocoileus virgin ianus) and
raccoon (Procyon Iotor) were observed along the stream banks. A variety of birds were
observed in the thickets and shrubs surrounding the stream channel and forest, including:
various sparrows.
2.2.5.1 Possible Invasive Wildlife
The following species were identified during site visits to the Middle Branch of Hewlett's
Creek; Asian tiger mosquito (Aedes albopictus), Bullfrog (Rana catesbeiana) (auditory
identification), European gypsy moth (Lymantria dispar), and European starling (Sturntts
vulgaris). The bullfrog is listed based on auditory identification by one of the project
researchers. The gypsy moth is listed based on visual identification of nests. The
mosquito and starling are listed due to their ubiquitous nature.
2.2.6 Endangered Species
The NCSU design team has not identified endangered plant or animal species or any such
habitat that would support the endangered species listed in this section. The NCSU
design team has made multiple visits to the Pine Valley Country Club and the restoration
site. Below is a list obtained from Natural Heritage, of the endangered of concern for
New Hanover County.
2.2.6.1 Endangered Flora
Vascular Plants:
Cooley's meadowrue
Rough-leaved loosestrife
Seabeach amaranth
Bog St. John's-wort
Carolina asphodel
Carolina bishopweed
Carolina beaksedge
Chapman's sedge
Coastal golden rod
"Dune bluecurls"
Pickering's dawnflower
Pondspice
Sandhills milkvetch
Savanna indigo-bush
Spiked medusa
Spring-flowering goldenrod
Tough bumelia
Endangered
Endangered
Threatened
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
12
I' J
RECEIVEt)
SFP ,g 2004
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Stream Restoration Plan ENHANCEMENTPRAM
Hewlett's Creek
New Hanover County, North Carolina
I amstem
ment
119001WA
August 31, 2004
A ;t
Biological
Agricultural
Engineering
WATER QUALITY SECTION
2739 -' ' `
4
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WETLANDS/ 401 GROUP
SEP 0 7 2004
Biological & Agricultural Engineering
Weaver Labs, Campus Box 7625
North Carolina State University
Raleigh, North Carolina 27695
1
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
TABLE OF CONTENTS
1.0 INTRODUCTION ............................................................1
1.1 PROJECT DESCRIPTION ..........................................2
1.2 GOALS AND OBJECTIVES ........................................2
1.3 STREAM SURVEY METHODOLOGY ...........................2
1.3.1 Stream Delineation - Classification .........................4
1.3.2 Bankfull Verification ..........................................4
2.0 EXISTING CONDITIONS ...................................................6
2.1 WATERSHED ....................................................... ..6
2. 1.1 General Description of the Watershed .................... ..6
2.1.2 Surface Waters Classification ............................. ...6
2.1.3 Soils of the Watershed ...................................... ...6
2.1.4 Land Use of the Watershed ...................................8
2.2 RESTORATION SITE ................................................8
2.2.1 Site Description .............................................. ..8
2.2.2 Existing Stream Characteristics ............................ ..8
2.2.3 Soils of the Restoration Site ................................ ..9
2.2.4 Terrestrial Plant Communities .............................. ..9
2.2.4.1 Managed Land ..................................... .12
2.2.4.2 Bottomland Forrest ............................... 12
2.2.4.3 Upland Hardwood Forest ........................ 12
2.2.4.4 Possible Invasive Flora ........................... 12
2.2.5 Wildlife Observations ........................................13
2.2.5.1 Possible Invasive Wildlife .......................... 13
2.2.6 Endangered Species ........................................... 13
2.2.6.1 Endangered Flora .................................. 13
2.2.6.1 Endangered Fauna ................................. 14
3.0 REFERENCE REACHES ...................................................15
3.1 JOHANNAH CREEK ...............................................15
3.2 PANTHER BRANCH ...............................................15
3.3 BATORORA BRANCH ............................................15
4.0 STREAM CHANNEL DESIGN ..................................... ....17
4.1 RESTORATION TECHNIQUES .................................22
4. 1.1 Dimension ......................................................22
4.1.2 Pattern ..........................................................22
4.1.3 Bedform ........................................................23
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.1.4 Riparian Areas ........ ........................................23
4.2 SEDIMENT TRANSPORT .........................................26
4.3 FLOODING ANALYSIS ... ........................................26
4.4 STRUCTURES .......................................................27
4.4.1 Cross Vane ............ ......................................... 27
4.4.2 Root Wads ............ .........................................27
4.4.3 Single Vanes .......... .........................................28
5.0 HABITAT RESTORATION ...............................................29
5.1 VEGETATION .......................................................29
5.2 RIPARIAN BUFFERS ..............................................30
5.2.1 Temporary Seeding ..........................................30
6.0 MONITORING ...............................................................31
6.1 STREAM CHANNEL ............................................... 31
6.2 VEGETATION .......................................................31
6.3 MACROINVERTEBRATES .......................................32
7.0 REFERENCES ...............................................................33
LIST OF TABLES
Table 1. Bank Erosion Potential ...............................................10
Table 2. Middle Branch of Hewlett's Creek Morphology .................16
Table 3. Priorities, Desc. & Summary for Incised River Restoration... 18
Table 4. Stream Monitoring Practices .......................................31
LIST OF FIGURES
Figure 1 Site Location ............................................................3
Figure 2 Watershed Arial ........................................................7
Figure 3 Soils Map ..............................................................11
Figure 4 Hewlett's Creek Restoration Plan ..................................19
Figure 5 Hewlett's Creek Restoration Plan .................................20
Figure 6 Hewlett's Creek Restoration Plan ..................................21
Figure 7 Typical Cross-Sections ..............................................24
Figure 8 Proposed Longitudinal Profile ......................................25
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
1.0 INTRODUCTION
The North Carolina Wetlands Restoration Program (NCWRP) has identified The Middle
Branch of Hewlett's Creek as a potential stream restoration site. Hewlett's Creek drains
into the Greenville Sound, the Middle Branch of Hewlett's creek (NCDWQ Stream Index
Number 18-87-26 SA HQW) is located on urban land in the southeast corner of
Wilmington in New Hanover County, North Carolina (Figure 1).
Arcadis first identified Hewlett's Creek as a potential restoration site in a feasibility
report to NCWRP. NCSU is completing the design and will conduct construction
oversight of the restoration of the middle branch of Hewlett's Creek. The portion of
Hewlett's creek that is being evaluated for restoration is within the property boundaries
of the Pine Valley Country Club. The Country Club Membership met on March 17`h of
2003 and voted to allow WRP to fund a restoration project focused on the Middle Branch
of Hewlett's Creek.
The Middle Branch of Hewlett's Creek has areas of significant active bank erosion
throughout the proposed project limits. There is evidence of historic straightening and
degradation resulting from this straightening. Thinning and removal of riparian
vegetation has also accelerated the degradation process. The incised condition of the
existing channel is accelerating the erosion process by forcing the channel to contain
larger then bankfull storm events.
The restoration site is located entirely within the property boundaries of the Pine Valley
Country Club. A City of Wilmington 16" RCP sewer line is located along the entire
length of the reach that is being considered for restoration. The sewer line crosses the
existing channel twice within the reach and is offset from the existing channel by a range
of loft to 40ft. There are two power-lines and numerous irrigation lines for the golf
course within the project limits. The Middle Branch of Hewlett's Creek has many urban
constraints, but should be an excellent potential restoration site, and . ideal for
demonstration and education.
Restoration requires determining how far the stream has departed from its natural
stability and then, establishing the stable form of the stream under the current hydrologic
conditions within the drainage area. The proposed restoration will construct a stable
meander geometry, modify channel cross-sections, and establish a floodplain at the
existing stream elevation, thus, restoring a stable dimension, pattern and profile. This
restoration is based on analysis of current watershed hydrologic conditions, evaluation of
the project site, and assessments of stable reference reaches. The following
recommendations are included in this restoration plan:
• Form a stable channel with the proper dimension, pattern and profile.
• Establish a floodplain along the stream channel.
• Place natural material structures in the stream to improve stability and enhance
aquatic habitat.
• Stabilize stream banks with herbaceous and woody vegetation
. 1
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
1.1 PROJECT DESCRIPTION
The Middle Branch of Hewlett's Creek project site is located in Hanover County, North
Carolina. The project is fully contained within the property of one landowner (The Pine
Valley Country Club). The project reach is bounded by The Long Street Drainage Cannel
to the west (upstream) and a 78" RCP culvert for Robert E. Lee Drive to the east
(downstream) (Figure 1).
1.2 GOALS AND OBJECTIVES
This project has the following goals and objectives:
1. Restore 3527 linear feet of The Middle Branch of Hewlett's Creek (as measured
along the centerline)
2. Provide a stable stream channel that neither aggrades nor degrades while maintaining
its dimension, pattern, and profile with the capacity to transport its watershed's water
and sediment load.
3. Improve water quality and reduce further property loss by stabilizing eroding stream
banks.
4. Establish a new floodplain at the existing stream elevation.
5. Improve aquatic habitat with the use of natural material stabilization structures such
as root wads; log vanes, woody debris and a riparian buffer.
1
6. Provide aesthetic value, wildlife habitat and bank stability through the creation or
enhancement of a riparian zone.
1.3 STREAM SURVEY METHODOLOGY
The US Forest Service General Technical Report RM-245, Stream Channel Reference
Sites: An Illustrated Guide to Field Technique is used as a guide when taking field
measurements. Accurate field measurements are critical to determine the present
condition of the existing channel, conditions of the floodplain, and watershed drainage
patterns.
2

The Middle Branch of Hewlett's Creek
New Hanover County, NC
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New Hanover County, NC North =+ ,
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FIGURE 1
SITE LOCATION
RESTORATION PLAN
I
3
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
NCSU contracted with W. K. Dickson to conduct a topographic survey of the restoration
site in August 2002. This mapping along with field measurements taken by NCSU staff
was used to evaluate present conditions, new channel alignment and grading volumes.
Mapping also provided locations of property pins, large trees, vegetation lines, and
culverts, roads, utilities and elevation contours.
A windshield survey was also conducted to determine the existing conditions within the
watershed. The watershed is fully (>90%) developed with residential dwellings and has
an area of 1.5 sq. miles
During the site visits, three cross-sections were taken using standard differential leveling
techniques. These cross-sections were used to gather detail on the present dimension and
condition of the channel. Bankfull cross-sectional area was calculated using the bankfull
features, the bankfull area at riffles varied between 26 sqft to 31 sqft.
1.3.1 Stream Delineation Criteria - Classification
Dave Rosgen developed his stream classification system in order to accomplish the
following:
1) Predict a river's behavior
2) Develop specific hydraulic and sediment relationships for a given stream type and its
state
3) Provide a mechanism to extrapolate site-specific data. to stream reaches having
similar characteristics
4) Provide a consistent frame of reference for communicating stream morphology and
condition among a variety of disciplines and interested parties
The Rosgen Stream Classification System is based on five criteria: width/depth ratio,
entrenchment ratio, slope, sinuosity, and channel materials. All cross-sections were
classified using this system.
1.3.2 Bankfull Verification
The foundation of Dave Rosgen's classification system is the concept of bankfull stage,
which is the point of incipient flooding. The width/depth and entrenchment ratios
described above depend on the correct assessment of bankfull. If bankfull is incorrectly
determined in the field, the entire restoration effort will be based on faulty data. It is
important to verify the physical indicators observed in the field with either gage data or a
regional curve to ensure the correct assessment of the bankfull stage.
The bankfull stage is determined in the field using physical indicators. The following is a
list of commonly used indicators that define bankfull (Rosgen, 1996):
4
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
• The presence of a floodplain at the elevation of incipient flooding.
• The elevation associated with the top of the highest depositional feature (e.g. point
bars, central bars within the active channel). These depositional features are
especially good stage indicators for channels in the presence of terrace or adjacent
colluvial slopes.
• A break in slope of the bank and/or a change in the particle size distribution, since
finer material is associated with deposition by overflow, rather than deposition of
coarser material within the active channel.
• Evidence of an inundation feature such as small benches below bankfull.
• Staining of rocks.
The most dominant bankfull indicators along The Middle Branch of Hewlett's Creek are
high scour lines and breaks in slope along the backs of narrow point bars.
The most common method of verifying bankfull stage is to compare the field determined
bankfull stage with measured stages at a stream gauging station. This calibration can be
performed if there is a stream gage within the study area's hydro-physiographic region.
In un-gauged areas, Dave Rosgen recommends verifying bankfull with the development
of regional curves. The regional curves normally plot bankfull discharge (QbkD, cross-
sectional area, width, and depth as a function of drainage area. The cross-sectional areas
of The Middle Branch of Hewlett's Creek was plotted on the Urban, Coastal Regional
Curve of North Carolina developed by the North Carolina State University (NCSU)
Water Quality Group, 2003 to help verify bankfull stage.
Data obtained from field surveys was used to compute the morphological characteristics
shown on the graph. The cross-sectional area for The Middle Branch of Hewlett's Creek
plots along the trend line for the Urban Regional Curve. The bankfull cross-sectional area
for the design channel was determined from evaluating the North Carolina regional curve
relationships and comparing them to the reference reach sites surveyed near the
restoration site. HEC-RAS was used to verify the design cross-sectional area for the
project.
5
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.0 EXISTING CONDITIONS
2.1 WATERSHED
2.1.1 General Description of the Watershed
The Middle Branch of the Hewlett Creek is a second order stream, is located within the
Coastal Physiographic Province of the Cape Fear River Basin (USGS Cataloging Unit). 030
The watershed is located in the Southeast corner of Wilmington, in New Hanover
County, North Carolina. The headwaters of the project originate approximately 2 miles to
the north-northeast of the restoration site. From the headwaters, Hewlett flows for
approximately 4.0 miles before emptying into the Greenville Sound just southwest of
Masonboro inlet. The land use within the study is mixed residential, commercial, and an
18-hole golf course.
The watershed is approximately 1.5 square miles (Figure 2). The watershed is oriented
north to south bending to the east before the project site. The topography ranges from
gently sloping to flat with relatively flat former floodplain that has be detached by
channeling the stream the middle of the past century. Land surface elevations range from
approximately 30 to 55 feet above mean sea level.
2.1.2 Surface Waters Classification
Surface waters in North Carolina are assigned a classification by the DWQ that is
designed to maintain, protect, and enhance water quality within the state. Hewlett's Creek
(NCDWQ Stream Index Number) is classified as a class SA HQW water body
(NCDENR, 2001). SA HQW water resources are waters protected for shellfish
propagation and survival, fishing, wildlife, secondary recreation, and agriculture.
2.1.3 Soils of the Watershed
The soils found in the watershed and adjacent to the stream can help determine the bed
and bank materials occurring in the stream. The Rosgen stream classification system uses
average particle size within the bankfull channel to help classify the stream. Knowing the
make up of the soils in the watershed, assists in understanding the anticipated bed-load
and sediment transport capacity of the stream.
Soils in upland areas within the watershed consist primarily of sand and urban complex
(draft maps and descriptions of the soils in the project area - New Hanover County Soil
Survey Office, Natural Resources Conservation Service [NRCS]). Depth to bedrock is
mapped as greater than 60 inches for the soils in the watershed. Soils in the side slopes
shoulders and summits of ridges include Baymeade-Urban Land complex 1 to 6 percent
slopes, and Rimini sand 1 to 6 percent slopes
6
The Middle Branch of Hewlett's Creek
New Hanover County, NC
The Middle Branch of Hewlett's Creek
New Hanover County, NC North
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FIGURE 2
WATERSHED ARIAL
RESTORATION PLAN
7
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.1.4 Land Use of the Watershed
Land use within the watershed is predominately urban residential (Figure 2). Evaluation
of a 1998 aerial photo obtained from New Hanover Country reveals that approximately
90% of the watershed is built out with single home residential areas, roads, businesses
and golf courses, with the remaining being water detention and forested urban land that is
not likely to be developed. The total percent impervious cover in the watershed is
approximately 20%-30%
2.2 RESTORATION SITE
The following sections provide a description of existing site conditions. This includes the
current stream conditions, soils, and surrounding plant communities.
2.2.1 Site Description
The Middle Branch of Hewlett's Creek restoration site begins approximately 4.0 miles
from its confluence with the Greenville Sound. The project is located within the property
boundaries of The Pine Valley Country Club. The middle Branch of Hewlett's Creek
flows from the west to east through a 0 to 35-foot wide floodplain. The majority of the
floodplain is located on the within the ditched channel of Hewlett's creek. The
floodplain typically ends abruptly at the toe of the adjoining steep slopes. A former
terrace extends along the entire length of the project and is 75 to 300 feet wide the
majority of the terrace is presently being used as fairway for the adjacent golf course.
The channel has long straight reaches with very minimal meanders. Channel sinuosity for
the entire reach is 1.05. High banks and areas of severe bank erosion can be found
throughout the project reach.
The main factor in the degradation and impairment for the Middle Branch of Hewlett's
Creek appears to be historic straightening of the channel and removal of riparian
vegetation. Straightening has increased the channel slope and decreased the stream
sinuosity. Erosion has caused increased sediment supply and channel widening. This has
combined to lead to the development of central bars in several straight sections of the
channel. Further development of central bars will increase erosion and lateral migration
of the channel.
2.2.2 Existing Stream Characteristics
Field surveys of the existing stream channel and site were conducted in August 2002.
The Middle Branch of Hewlett's Creek Restoration Site can be typically defined as a
predominantly straight channel with poor habitat. Stream banks are steep with areas of
active erosion. Long straight sections of the channel have central bars forming; indicating
the channel is over-wide. Instead of focusing the flow along the thalweg, the central bars
deflect the stream-flow toward the banks and accelerate bank erosion.
8
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
flow toward the banks and accelerate bank erosion.
Riffle bankfull widths ` range, from 24 to 30 feet with mean depths
ranging from 1.2 to 1.5 feet. The cross-sectional areas for these riffles range from 26.0 to
31.5 square feet. All of the cross-sections were taken within the reach to be restored. All
cross-sections classed as type-F or G channels as the amount of incision increases
downstream. The stream has the following average characteristics:
Bankfull Width: 27 feet
Bankfull Cross-sectional Area: 30 square feet
Bankfull Mean Depth: 1.3 feet
Bankfull Maximum Depth: 4.1 feet
Average Water Surface Slope: 0.002 feet/feet
Entrenchment Ratio: >6.0
Sinuosity: <1.05
Bank Height Ratio 2.0
The entire length of channel within the restoration site was rated using the Bank Erosion
Hazard Index (BEHI). The most likely bank to erode was assessed throughout the reach.
The reach was subdivided into sections with similar erosional characteristics such as
surface protection, root depth, root density, and bank angle. Results are listed in Table 1.
The overall restoration reach has a BEHI rating of high, although two sections had a
BHEI rating of very high and extreme. It is likely these two areas will expand as erosion
continues. The main cause of the very high and extreme ratings are due to the lack of
significant deep rooting vegetation and surface protection. Restoration will reestablish
deep rooting vegetation along the banks throughout the entire reach.
2.2.3 Soils of the Restoration Site
According to the preliminary soil maps for New Hanover County, soils adjacent to the
Middle Branch of Creek within the restoration site are mapped as Rimini, Baymeade and
Lynn Haven soils (Figure 3). Investigation of the soils adjacent to the stream indicates
that all three soils are present, although Lynn Haven is the most common. Lynn Haven is
a fine sandy soil that is well drained. These permeable soils occur on nearly level
floodplains along creeks and rivers. The original wetland soils where most likely covered
and removed when the golf course was built up and the creek was straightened
Soil textures encountered include sand and fine sand. The seasonal high water table was
observed to be greater than 40 inches for most soils within the project. Slopes range from
0 to 6 percent.
2.2.4 Terrestrial Plant Communities
The following sections describe the existing plant communities on and adjacent to the
restoration site. For purposes of this project, three plant communities are described:
Managed Land, Bottomland Forest, and Upland Hardwood Forest. Nomenclature follows
Radford (1968).
9

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New Hanover County, NC
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New Hanover County, NC
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FIGURE 3
SOILS MAP
RESTORATION PLAN
11
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.2.5 Wildlife Observations
Wildlife and signs of wildlife were noted during on-site visits, however, a formal wildlife
survey was not performed. Tracks of white tailed deer (Odocoileus virgin ialtus) and
raccoon (Procyon Iotor) were observed along the stream banks. A variety of birds were
observed in the thickets and shrubs surrounding the stream channel and forest, including:
various sparrows.
2.2.5.1 Possible Invasive Wildlife
The following species were identified during site visits to the Middle Branch of Hewlett's
Creek; Asian tiger mosquito (Aedes albopictus), Bullfrog (Rana catesbeiana) (auditory
identification), European gypsy moth (Lyniantria dispar), and European starling (Stunius
vulgaris). The bullfrog is listed based on auditory identification by one of the project
researchers. The gypsy moth is listed based on visual identification of nests. The
mosquito and starling are listed due to their ubiquitous nature.
2.2.6 Endangered Species
The NCSU design team has not identified endangered plant or animal species or any such
habitat that would support the endangered species listed in this section. The NCSU
design team has made multiple visits to the Pine Valley Country Club and the restoration
site. Below is a list obtained from Natural Heritage, of the endangered of concern for
New Hanover County.
2.2.6.1 Endangered Flora
Vascular Plants:
Cooley's meadowrue
Rough-leaved loosestrife
Seabeach amaranth
Bog St. John's-wort
Carolina asphodel
Carolina bishopweed
Carolina beaksedge
Chapman's sedge
Coastal golden rod
"Dune bluecurls"
Pickering's dawnflower
Pondspice
Sandhills milkvetch
Savanna indigo-bush
Spiked medusa
Spring-flowering goldenrod
Tough bumelia
Endangered
Endangered
Threatened
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
12
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Venus flytrap Federal Species of Concern
2.2.6.2 Endangered Fauna
Vertebrates:
Red-cockaded woodpecker Endangered
Shortnose sturgeon Endangered
West Indian Manatee Endangered
American Alligator Threatened
Green sea turtle Threatened
Loggerhead sea turtle Threatened
Piping Plover Threatened
Carolina gopher frog Federal Species of Concern
Eastern painted bunting Federal Species of Concern
Mimic glass lizard Federal Species of Concern
Northern pine snake Federal Species of Concern
Southeastern myotis Federal Species of Concern
Southern Hognose snake Federal Species of Concern
Invertebrates:
Arogos skipper
Buchholz's dart mouth
Cape Fear threetooth
Croatan crayfish
Magnificent rams-horn
Rare skipper
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
13
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
3.0 REFERENCE REACHES
Reference reaches were utilized on which the morphological characteristics were
measured to determine a range of values for the stable dimension, pattern, and profile of
the proposed channel. The following sections include a detail of three of the reference
reaches that were used for design of the restoration plan for the Middle Branch of
Hewlett's Creek. The reference reaches used along with the bankfull area, and current
constraints as the base for the preliminary design.
3.1 JOHANNAH CREEK
The Johannah creek has a drainage area of 1.18 square miles. Angela Moreland of the
NCSU Water Quality group completed the stream survey of Johannah creek in the
summer of 2001. The stream had a bankfull channel width of 10.4 feet and a bankfull
mean depth of 0.8 feet. Johannah Creek is a C5 stream type from Rosgen Classification
system. The morphological characteristics of this reference stream are included in Table
2.
3.2 PANTHER BRANCH
The Panther branch has a drainage area of 1.69 square miles. Angela Moreland of the
NCSU Water Quality group completed the stream survey of Panther branch in the
summer of 2001. The stream had a bankfull channel width of 11.5 feet and a bankfull
mean depth of 1.6 feet. Panther Branch is an E5 stream type from Rosgen Classification
system. The morphological characteristics of this reference stream are included in Table
2.
3.3 BATORORA BRANCH
Angela Moreland of the NCSU Water Quality group completed the stream survey of
Batorora branch in the summer of 2001. The stream had a bankfull channel width of 15.5
feet and a bankfull mean depth of 1.5 feet. Batorora Branch is an E5 stream type from
Rosgen Classification system. The morphological characteristics of this reference stream
are included in Table 2.
15
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Table 2. Middle Branch of Hewlett's Creek Morphology (Existing,
Design, and Reference)
Parameter Existing Reference Reference Reference Design
Reach Name Hewlett Panther Johannah Batorora Hewlett
Bankfull XSEC Area, Abkf (ft) 30 17.9 8.6 23.9 30
Bankfull Width, Wbkf (ft) 20 11.5 10.4 15.5 19
Bankfull Mean Depth, Dbkf (ft) 1.5 1.6 0.8 1.5 1.6
Width to Depth Ratio, W/D (ft/ft) 13.3 7.4 12.6 10.1 12
Entrenchment Ratio, Wfpa/Wbkf (ft/ft) 2 17.4 19.2 12.9 3
Bank Height Ratio, Dtob/Dmax (ft/ft) 2.0 1 1 1 1
Min Bkf Max Depth, Dmax (ft) 1.6 --- --- --- 2.1
Max Bkf Max Depth, Dmax (ft) 1.9 --- - - 2.8
Min Bkf Max Depth, Dmax/Dbkf 1.1 1.6 1.3 1.4 1.3
Max Bkf Max Depth, Dmax/Dbkf 1.3 1.8
Min Meander Length, Lm (ft) 100 --- - - 86
Max Meander Length, Lm (ft) 280 --- - - 171
Min Meander Ion Ratio, Im/Wbkf 5 2.3 1.9 4.1 4.5
Max Meander Len Ratio, Lm/Wbkf 14 9.1 5.1 6.8 9
Min Radius of Curvature, Rc (ft) 60 --- --- --- 34
Max Radius of Curvature, Rc (ft) 80 --- --- --- 49
Min Rc Ratio, Rc/Wbkf 3 0.5 0.9 0.7 1.8
Max Rc Ratio, Rc/Wbkf 4 1.5 2.3 2.6 2.6
Min Belt Width, Wblt (ft) 25 --- --- --- 42
Max Belt Width, Wblt (ft) 40 --- - - 76
Min MW Ratio, Wblt/Wbkf (ft) 1.3 1.9 1.3 2.9 2.2
Max MW Ratio, Wblt/Wbkf (ft) 2 8.7 4.4 4.5 4
Sinuosity, K 1.05 1.2 1.2 1.2 1.2
Valley Slope, Sval (ft/ft) .0026 .0040 .0026 .0061 .0026
Channel Slope, Schan=Sval/K (ft/ft) .0025 .0033 .0021 .0051 .0021
Pool Slope, Spool (ft/ft) 0 --- - --- 0
Pool Slope Ratio, Spool/Schan 0 0 0 0
Min Pool Depth, Dpool (ft) 1.7 --- --- --- 2.4
Max Pool Depth, Dpool (ft) 2 --- --- --- 3.0
Min Pool Depth Ratio, DpooUDbkf 1.1 1.6 1.9 2 1.5
Max Pool Depth Ratio, DpooUDbkf 1.3 2
Min Pool Width, Wpool (ft) 21 --- --- --- 19
Max Pool Width, Wpool (ft) 25 --- - - 22.8
Min Pool Wid Ratio, Wpool/Wbkf 1.1 1 1.2 0.9 1
Max Pool Wid Ratio, Wpool/Wbkf 1.3 1.2
Min Length Pool Spacing, Lps (ft) 40 --- --- --- 57,
Max Length Pool Spacing, Lps (ft) 220 --- --- --- 114
Min Pool Spacing Ratio, Lps/Wbkf 2 1.3 1.2 1.7 3
Max Pool Spacing Ratio, Lps/Wbkf 11 5.7 3.8 3.9 6
16
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
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Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.0 STREAM CHANNEL DESIGN
This restoration will classify as a Priority 2 restoration (Rosgen, 1997). The floodplain'
will be re-established to fit the existing or slightly raised stream profile. The grade of the
stream will be raised in some areas and a floodplain will be established at the new
bankfull elevation. Table 3 describes and summarizes the four priorities of incised river
restoration (Rosgen, 1997). The proposed stream restoration will restore the natural
meander pattern, modify channel cross-section restore bedform, improve sediment
transport capacity, enhance habitat, and re-establish a floodplain for the stream.
The design was based upon Dave Rosgen's natural channel design methodology. As
described in Section 3.0, reference reaches were utilized on which the morphological
characteristics were measured to determine a range of values for the stable dimension,
pattern, and profile of the proposed channel. The measured and proposed morphological
characteristic's are shown in Table 2.
A conceptual design was developed from the range of values listed in Table 2. This
stream restoration project will result in approximately 3,600 restored linear feet (as
measure from the thalweg) of The Middle Branch of Hewlett's Creek. The plan view of
the proposed restoration design can be seen in Figures 4, 5 and 6.
17
3. Open Water Impacts, including Lakes, Ponds, Estuaries, Sounds, Atlantic Ocean and any
other Water of the U.S.
Open Water Impact
Site Number
(indicate on ma)
Type of Impact* Area of
Impact
(acres) Name of Waterbody
(if applicable) Type of Waterbody
(lake, pond, estuary, sound,
bay, ocean, etc.)

* List each impact separately and identify temporary impacts. Impacts include, but are not limited to: fill, excavation, dredging,
flooding, drainage, bulkheads, etc.
4. Pond Creation
If construction of a pond is proposed, associated wetland and stream impacts should be
included above in the wetland and stream impact sections. Also, the proposed pond should
be described here and illustrated on any maps included with this application.
Pond to be created in (check all that apply): ? uplands ? stream ? wetlands
Describe the method of construction (e.g., dam/embankment, excavation, installation of
draw-down valve or spillway, etc.):
Proposed use or purpose of pond (e.g., livestock watering, irrigation, aesthetic, trout pond,
local stormwater requirement, etc.):
Size of watershed draining to pond: Expected pond surface area:
VII. Impact Justification (Avoidance and Minimization)
Specifically describe measures taken to avoid the proposed impacts. It may be useful to provide
information related to site constraints such as topography, building ordinances, accessibility, and
financial viability of the project. The applicant may attach drawings of alternative, lower-impact
site layouts, and explain why these design options were not feasible. Also discuss how impacts
were minimized once the desired site plan was developed. If applicable, discuss construction
techniques to be followed during construction to reduce impacts.
SEE PLAN
VIII. Mitigation
DWQ - In accordance with 15A NCAC 2H .0500, mitigation may be required by the NC
Division of Water Quality for projects involving greater than or equal to one acre of impacts to
freshwater wetlands or greater than or equal to 150 linear feet of total impacts to perennial
streams.
Page 9 of 12
IX. Environmental Documentation (DWQ Only)
Does the project involve an expenditure of public funds or the use of public (federal/state/local)
land?
Yes ® No ?
If yes, does the project require preparation of an environmental document pursuant to the
requirements of the National or North Carolina Environmental Policy Act (NEPA/SEPA)?
Note: If you are not sure whether a NEPA/SEPA document is required, call the SEPA
coordinator at [phone] to review current thresholds for environmental documentation.
Yes ? No
If yes, has the document review been finalized by the State Clearinghouse? If so, please attach a
copy of the NEPA or SEPA final approval letter.
Yes ? No ?
X. Proposed Impacts on Riparian and Watershed Buffers (DWQ Only)
It is the applicant's (or agent's) responsibility to determine, delineate and map all impacts to
required state and local buffers associated with the project. The applicant must also provide
justification for these impacts in Section VII above. All proposed impacts must be listed herein,
and must be clearly identifiable on the accompanying site plan. All buffers must be shown on a
map, whether or not impacts are proposed to the buffers. Correspondence from the DWQ
Regional Office may be included as appropriate. Photographs may also be included at the
applicant's discretion.
Will the project impact protected riparian buffers identified within 15A NCAC 2B .0233
(Neuse), 15A NCAC 2B .0259 (Tar-Pamlico), 15A NCAC 2B .0250 (Randleman Rules and
Water Supply Buffer Requirements), or other (please identify )?
Yes ? No ® If you answered "yes", provide the following information:
Identify the square feet and acreage of impact to each zone of the riparian buffers. If buffer
mitigation is required calculate the required amount of mitigation by applying the buffer
multipliers.
Zone* Impact
(square feet) Multiplier Required
Mitigation
1 3
2 1.5
Total
* Zone 1 extends out 30 feet perpendicular from near bank of channel; "Lone 2 extends an
additional 20 feet from the edge of Zone 1.
Page I I of 12
North Carolina.
Department of Environment and Natural Resources
00
Michael F. Easley, Governor
C n% EN, a R
William G. Ross Jr., Secretary r ,? ?t1
MEMORANDUM:
®.;3
O
TO: John Dorney r
t 11F
FROM: Ron Ferrell
Sp
SUBJECT: Permit Application-Hewlett's Creek 2003
DATE: 9-24-03
Attached for your review are 2 restoration plans for the Hewlett's Creek Stream
Restoration project in New Hanover County. Please feel free to call the project manager
(Mac Haupt) with any questions regarding this plan (733-5314).
Thank you very much for your assistance.
attachment: Restoration Plan (2 originals)

q
1
Wetlands Restoration Program 1619 Mail Service Center Raleigh, NC 27699-1619
[phone] Fax: [phone]

RECEIVED
S E P 3 2004
NC ECOSYSTEM
ENHANCEMENT PROGRAM
Stream Restoration Plan
Hewlett's Creek
New Hanover County, North Carolina
LEC1,111 stem
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WETLANDS 1401 GROUP
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SEP 0 7 2004
August 31, 2004
WATER QUALITY SECTION
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Agricultural
Engineering
Biological & Agricultural Engineering
Weaver Labs, Campus Box 7625
North Carolina State University
Raleigh, North Carolina 27695
i .
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
TABLE OF CONTENTS
1.0 INTRODUCTION ............................................................1
1.1 PROJECT DESCRIPTION ..........................................2
1.2 GOALS AND OBJECTIVES ........................................2
1.3 STREAM SURVEY METHODOLOGY ...........................2
1.3.1 Stream Delineation - Classification .........................4
1.3.2 Bankfull Verification ..........................................4
2.0 EXISTING CONDITIONS ...................................................6
2.1 WATERSHED ....................................................... .. 6
2.1.1 General Description of the Watershed .................... ..6
2.1.2 Surface Waters Classification ............................. ...6
2.1.3 Soils of the Watershed .........................................6
2.1.4 Land Use of the Watershed ................................. ..8
2.2 RESTORATION SITE ................................................8
2.2.1 Site Description .............................................. ..8
2.2.2 Existing Stream Characteristics ............................ ..8
2.2.3 Soils of the Restoration Site ................................ ..9
2.2.4 Terrestrial Plant Communities .............................. ..9
2.2.4.1 Managed Land ......................................12
2.2.4.2 Bottomland Forrest ............................... 12
2.2.4.3 Upland Hardwood Forest ........................ 12
2.2.4.4 Possible Invasive Flora ........................... 12
2.2.5 Wildlife Observations ........................................ 13
2.2.5.1 Possible Invasive Wildlife .......................... 13
2.2.6 Endangered Species ........................................... 13
2.2.6.1 Endangered Flora .................................. 13
2.2.6.1 Endangered Fauna ................................. 14
3.0 REFERENCE REACHES ...................................................15
3.1 JOHANNAH CREEK ...............................................15
3.2 PANTHER BRANCH ...............................................15
3.3 BATORORA BRANCH ............................................15
4.0 STREAM CHANNEL DESIGN ...........................................17
4.1 RESTORATION TECHNIQUES .................................22
4.1.1 Dimension ......................................................22
4.1.2 Pattern ..........................................................22
4.1.3 B edform ........................................................23

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.1.4 Riparian Areas .......... ......................................23
4.2 SEDIMENT TRANSPORT ... ......................................26
4.3 FLOODING ANALYSIS ..... ......................................26
4.4 STRUCTURES ................. ......................................27
4.4.1 Cross Vane .....................................................27
4.4.2 Root Wads ............... ......................................27
4.4.3 Single Vanes ............ .......................................28
5.0 HABITAT RESTORATION ............. ................................29
5.1 VEGETATION .......................................................29
5.2 RIPARIAN BUFFERS ..............................................30
5.2.1 Temporary Seeding ..........................................30
3
6.0 MONITORING ...............................................................
6.1 STREAM CHANNEL ...............................................31
6.2 VEGETATION ....................................................... 31
6.3 MACROINVERTEBRATES .......................................32
7.0 REFERENCES ...............................................................33
LIST OF TABLES
Table 1. Bank Erosion Potential ............................................... 10
Table 2. Middle Branch of Hewlett's Creek Morphology .................16
Table 3. Priorities, Desc. & Summary for Incised River Restoration... 18
Table 4. Stream Monitoring Practices .......................................31
LIST OF FIGURES
Figure 1 Site Location ............................................................
1
Figure 3 Soils Map ..............................................................
Figure 2 Watershed Arial ........................................................7
Figure 6 Hewlett's Creek Restoration Plan ..................................21
Figure 7 Typical Cross-Sections ..............................................24
Figure 8 Proposed Longitudinal Profile ......................................25
Figure 4 Hewlett's Creek Restoration Plan ..................................19
Figure 5 Hewlett's Creek Restoration Plan .................................20
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
1.1 PROJECT DESCRIPTION
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
1.0 INTRODUCTION
The North Carolina Wetlands Restoration Program (NCWRP) has identified The Middle
Branch of Hewlett's Creek as a potential stream restoration site. Hewlett's Creek drains
into the Greenville Sound, the Middle Branch of Hewlett's creek (NCDWQ Stream Index
Number 18-87-26 SA HQW) is located on urban land in the southeast corner of
Wilmington in New Hanover County, North Carolina (Figure 1).
Arcadis first identified Hewlett's Creek as a potential restoration site in a feasibility
report to NCWRP. NCSU is completing the design and will conduct construction
oversight of the restoration of the middle branch of Hewlett's Creek. The portion of
Hewlett's creek that is being evaluated for restoration is within the property boundaries
of the Pine Valley Country Club. The Country Club Membership met on March 17th of
2003 and voted to allow WRP to fund a restoration project focused on the Middle Branch
of Hewlett's Creek.
The Middle Branch of Hewlett's Creek has areas of significant active bank erosion
throughout the proposed project limits. There is evidence of historic straightening and
degradation resulting from this straightening. Thinning and removal of riparian
vegetation has also accelerated the degradation process. The incised condition of the
existing channel is accelerating the erosion process by forcing the channel to contain
larger then bankfull storm events.
The restoration site is located entirely within the property boundaries of the Pine Valley
Country Club. A City of Wilmington 16" RCP sewer line is located along the entire
length of the reach that is being considered for restoration. The sewer line crosses the
existing channel twice within the reach and is offset from the existing channel by a range
of loft to 40ft. There are two power-lines and numerous irrigation lines for the golf
course within the project limits. The Middle Branch of Hewlett's Creek has many urban
constraints, but should be an excellent potential restoration site, and , ideal for
demonstration and education.
Restoration requires determining how far the stream has departed from its natural
stability and then, establishing the stable form of the stream under the current hydrologic
conditions within the drainage area. The proposed restoration will construct a stable
meander geometry, modify channel cross-sections, and establish a floodplain at the
existing stream elevation, thus, restoring a stable dimension, pattern and profile. This
restoration is based on analysis of current watershed hydrologic conditions, evaluation of
the project site, and assessments of stable reference reaches. The following
recommendations are included in this restoration plan:
• Form a stable channel with the proper dimension, pattern and profile.
• Establish a floodplain along the stream channel.
• Place natural material structures in the stream to improve stability and enhance
aquatic habitat.
Stabilize stream banks with herbaceous and woody vegetation
1

The Middle Branch of Hewlett's Creek
New Hanover County, NC
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The Middle Branch of Hewlett's Creek
New Hanover County, NC North
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FIGURE I
SITE LOCATION
RESTORATION PLAN
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Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
NCSU contracted with W. K. Dickson to conduct a topographic survey of the restoration
site in August 2002. This mapping along with field measurements taken by NCSU staff
was used to evaluate present conditions, new channel alignment and grading volumes.
Mapping also provided locations of property pins, large trees, vegetation lines, and
culverts, roads, utilities and elevation contours.
A windshield survey was also conducted to determine the existing conditions within the
watershed. The watershed is fully (>90%) developed with residential dwellings and has
an area of 1.5 sq. miles
During the site visits, three cross-sections were taken using standard differential leveling
techniques. These cross-sections were used to gather detail on the present dimension and
condition of the channel. Bankfull cross-sectional area was calculated using the bankfull
features, the bankfull area at riffles varied between 26 sgft to 31 sqft.
1.3.1 Stream Delineation Criteria - Classification
Dave Rosgen developed his stream classification system in order to accomplish the
following:
1) Predict a river's behavior
2) Develop specific hydraulic and sediment relationships for a given stream type and its
state
3) Provide a mechanism to extrapolate site-specific data. to stream reaches having
similar characteristics
4) Provide a consistent frame of reference for communicating stream morphology and
condition among a variety of disciplines and interested parties
The Rosgen Stream Classification System is based on five criteria: width/depth ratio,
entrenchment ratio, slope, sinuosity, and channel materials. All cross-sections were
classified using this system.
1.3.2 Bankfull Verification
The foundation of Dave Rosgen's classification system is the concept of bankfull stage,
which is the point of incipient flooding. The width/depth and entrenchment ratios
described above depend on the correct assessment of bankfull. If bankfull is incorrectly
determined in the field, the entire restoration effort will be based on faulty data. It is
important to verify the physical indicators observed in the field with either gage data or a
regional curve to ensure the correct assessment of the bankfull stage.
The bankfull stage is determined in the field using physical indicators. The following is a
list of commonly used indicators that define bankfull (Rosgen, 1996):
4
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
• The presence of a floodplain at the elevation of incipient flooding.
• The elevation associated with the top of the highest depositional feature (e.g. point
bars, central bars within the active channel). These depositional features are
especially good stage indicators for channels in the presence of terrace or adjacent
colluvial slopes.
• A break in slope of the bank and/or a change in the particle size distribution, since
finer material is associated with deposition by overflow, rather than deposition of
coarser material within the active channel.
• Evidence of an inundation feature such as small benches below bankfull.
• Staining of rocks.
The most dominant bankfull indicators along The Middle Branch of Hewlett's Creek are
high scour lines and breaks in slope along the backs of narrow point bars.
The most common method of verifying bankfull stage is to compare the field determined
bankfull stage with measured stages at a stream gauging station. This calibration can be
performed if there is a stream gage within the study area's hydro-physiographic region.
In un-gauged areas, Dave Rosgen recommends verifying bankfull with the development
of regional curves. The regional curves normally plot bankfull discharge (QbkD, cross-
sectional area, width, and depth as a function of drainage area. The cross-sectional areas
of The Middle Branch of Hewlett's Creek was plotted on the Urban, Coastal Regional
Curve of North Carolina developed by the North Carolina State University (NCSU)
Water Quality Group, 2003 to help verify bankfull stage.
Data obtained from field surveys was used to compute the morphological characteristics
shown on the graph. The cross-sectional area for The Middle Branch of Hewlett's Creek
plots along the trend line for the Urban Regional Curve. The bankfull cross-sectional area
for the design channel was determined from evaluating the North Carolina regional curve
relationships and comparing them to the reference reach sites surveyed near the
restoration site. HEC-RAS was used to verify the design cross-sectional area for the
project.
5
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.0 EXISTING CONDITIONS
2.1 WATERSHED
2.1.1 General Description of the Watershed
The Middle Branch of the Hewlett Creek is a second order stream, is located within the
Coastal Physiographic Province of the Cape Fear River Basin (USGS Cataloging Unit). 03
The watershed is located in the Southeast corner of Wilmington, in New Hanover
County, North Carolina. The headwaters of the project originate approximately 2 miles to
the north-northeast of the restoration site. From the headwaters, Hewlett flows for
approximately 4.0 miles before emptying into the Greenville Sound just southwest of
Masonboro inlet. The land use within the study is mixed residential, commercial, and an
18-hole golf course.
The watershed is approximately 1.5 square miles (Figure 2). The watershed is oriented
north to south bending to the east before the project site. The topography ranges from
gently sloping to flat with relatively flat former floodplain that has be detached by
channeling the stream the middle of the past century. Land surface elevations range from
approximately 30 to 55 feet above mean sea level.
2.1.2 Surface Waters Classification
Surface waters in North Carolina are assigned a classification by the DWQ that is
designed to maintain, protect, and enhance water quality within the state. Hewlett's Creek
(NCDWQ Stream Index Number) is classified as a class SA HQW water body
(NCDENR, 2001). SA HQW water resources are waters protected for shellfish
propagation and survival, fishing, wildlife, secondary recreation, and agriculture.
2.1.3 Soils of the Watershed
The soils found in the watershed and adjacent to the stream can help determine the bed
and bank materials occurring in the stream. The Rosgen stream classification system uses
average particle size within the bankfull channel to help classify the stream. Knowing the
make up of the soils in the watershed, assists in understanding the anticipated bed-load
and sediment transport capacity of the stream.
Soils in upland areas within the watershed consist primarily of sand and urban complex
(draft maps and descriptions of the soils in the project area - New Hanover County Soil
Survey Office, Natural Resources Conservation Service [NRCS]). Depth to bedrock is
mapped as greater than 60 inches for the soils in the watershed. Soils in the side slopes
shoulders and summits of ridges include Baymeade-Urban Land complex 1 to 6 percent
slopes, and Rimini sand 1 to 6 percent slopes
6
The Middle Branch of Hewlett's Creek
New Hanover County, NC
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WATERSHED ARIAL
RESTORATION PLAN
7
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.1.4 Land Use of the Watershed
Land use within the watershed is predominately urban residential (Figure 2). Evaluation
of a 1998 aerial photo obtained from New Hanover Country reveals that approximately
90% of the watershed is built out with single home residential areas, roads, businesses
and golf courses, with the remaining being water detention and forested urban land that is
not likely to be developed. The total percent impervious cover in the watershed is
approximately 20%-30%
2.2 RESTORATION SITE
The following sections provide a description of existing site conditions. This includes the
current stream conditions, soils, and surrounding plant communities.
2.2.1 Site Description
The Middle Branch of Hewlett's Creek restoration site begins approximately 4.0 miles
from its confluence with the Greenville Sound. The project is located within the property
boundaries of The Pine Valley Country Club. The middle Branch of Hewlett's Creek
flows from the west to east through a 0 to 35-foot wide floodplain. The majority of the
floodplain is located on the within the ditched channel of Hewlett's creek. The
floodplain typically ends abruptly at the toe of the adjoining steep slopes. A former
terrace extends along the entire length of the project and is 75 to 300 feet wide the
majority of the terrace is presently being used as fairway for the adjacent golf course.
The channel has long straight reaches with very minimal meanders. Channel sinuosity for
the entire reach is 1.05. High banks and areas of severe bank erosion can be found
throughout the project reach.
The main factor in the degradation and impairment for the Middle Branch of Hewlett's
Creek appears to be historic straightening of the channel and removal of riparian
vegetation. Straightening has increased the channel slope and decreased the stream
sinuosity. Erosion has caused increased sediment supply and channel widening. This has
combined to lead to the development of central bars in several straight sections of the
channel. Further development of central bars will increase erosion and lateral migration
of the channel.
2.2.2 Existing Stream Characteristics
Field surveys of the existing stream channel and site were conducted in August 2002.
The Middle Branch of Hewlett's Creek Restoration Site can be typically defined as a
predominantly straight channel with poor habitat. Stream banks are steep with areas of
active erosion. Long straight sections of the channel have central bars forming; indicating
the channel is over-wide. Instead of focusing the flow along the thalweg, the central bars
deflect the stream-flow toward the banks and accelerate bank erosion.
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
flow toward the banks and accelerate bank erosion.
Riffle bankfull widths ' range. from 24 to 30 feet with mean depths
ranging from 1.2 to 1.5 feet. The cross-sectional areas for these riffles range from 26.0 to
31.5 square feet. All of the cross-sections were taken within the reach to be restored. All
cross-sections classed as type-F or G channels as the amount of incision increases
downstream. The stream has the following average characteristics:
Bankfull Width: 27 feet
Bankfull Cross-sectional Area: 30 square feet
Bankfull Mean Depth: 1.3 feet
B ankfull Maximum Depth: 4.1 feet
Average Water Surface Slope: 0.002 feet/feet
Entrenchment Ratio: >6.0
Sinuosity: <1.05
Bank Height Ratio 2.0
The entire length of channel within the restoration site was rated using the Bank Erosion
Hazard Index (BEHI). The most likely bank to erode was assessed throughout the reach.
The reach was subdivided into sections with similar erosional characteristics such as
surface protection, root depth, root density, and bank angle. Results are listed in Table 1.
The overall restoration reach has a BEHI rating of high, although two sections had a
BHEI rating of very high and extreme. It is likely these two areas will expand as erosion
continues. The main cause of the very high and extreme ratings are due to the lack of
significant deep rooting vegetation and surface protection. Restoration will reestablish
deep rooting vegetation along the banks throughout the entire reach.
2.2.3 Soils of the Restoration Site
According to the preliminary soil maps for New Hanover County, soils adjacent to the
Middle Branch of Creek within the restoration site are mapped as Rimini, Baymeade and
Lynn Haven soils (Figure 3). Investigation of the soils adjacent to the stream indicates
that all three soils are present, although Lynn Haven is the most common. Lynn Haven is
a fine sandy soil that is well drained. These permeable soils occur on nearly level
floodplains along creeks and rivers. The original wetland soils where most likely covered
and removed when the golf course was built up and the creek was straightened
Soil textures encountered include sand and fine sand. The seasonal high water table was
observed to be greater than 40 inches for most soils within the project. Slopes range from
0 to 6 percent.
2.2.4 Terrestrial Plant Communities
The following sections describe the existing plant communities on and adjacent to the
restoration site. For purposes of this project, three plant communities are described:
Managed Land, Bottomland Forest, and Upland Hardwood Forest. Nomenclature follows
Radford (1968).
9

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The Middle Branch of Hewlett's Creek
New Hanover County, NC
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New Hanover County, NC
NORTH
0 0.125 0.25 0.5 0.75 1
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Bladen Pendor Orslow
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FIGURE 3
SOILS MAP
RESTORATION PLAN
11
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.2.5 Wildlife Observations
Wildlife and signs of wildlife were noted during on-site visits, however, a formal wildlife
survey was not performed. Tracks of white tailed deer (Odocoileus virgin ianus) and
raccoon (Procyon Iotor) were observed along the stream banks. A variety of birds were
observed in the thickets and shrubs surrounding the stream channel and forest, including:
various sparrows.
2.2.5.1 Possible Invasive Wildlife
The following species were identified during site visits to the Middle Branch of Hewlett's
Creek; Asian tiger mosquito (Aedes albopictus), Bullfrog (Rana catesbeiaua) (auditory
identification), European gypsy moth (Lymantria dispar), and European starling (Sturnus
vulgaris). The bullfrog is listed based on auditory identification by one of the project
researchers. The gypsy moth is listed based on visual identification of nests. The
mosquito and starling are listed due to their ubiquitous nature.
2.2.6 Endangered Species
The NCSU design team has not identified endangered plant or animal species or any such
habitat that would support the endangered species listed in this section. The NCSU
design team has made multiple visits to the Pine Valley Country Club and the restoration
site. Below is a list obtained from Natural Heritage, of the endangered of concern for
New Hanover County.
2.2.6.1 Endangered Flora
Vascular Plants:
Cooley's meadowrue Endangered
Rough-leaved loosestrife Endangered
Seabeach amaranth Threatened
Bog St. John's-wort Federal Species of Concern
Carolina asphodel Federal Species of Concern
Carolina bishopweed Federal Species of Concern
Carolina beaksedge Federal Species of Concern
Chapman's sedge Federal Species of Concern
Coastal golden rod Federal Species of Concern
"Dune bluecurls" Federal Species of Concern
Pickering's dawnflower Federal Species of Concern
Pondspice Federal Species of Concern
Sandhills milkvetch Federal Species of Concern
Savanna indigo-bush Federal Species of Concern
Spiked medusa Federal Species of Concern
Spring-flowering goldenrod Federal Species of Concern
Tough bumelia Federal Species of Concern
12
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Venus flytrap Federal Species of Concern
2.2.6.2 Endangered Fauna
Vertebrates:
Red-cockaded woodpecker Endangered
Shortnose sturgeon Endangered
West Indian Manatee Endangered
American Alligator Threatened
Green sea turtle Threatened
Loggerhead sea turtle Threatened
Piping Plover Threatened
Carolina gopher frog Federal Species of Concern
Eastern painted bunting Federal Species of Concern
Mimic glass lizard Federal Species of Concern
Northern pine snake Federal Species of Concern
Southeastern myotis Federal Species of Concern
Southern Hognose snake Federal Species of Concern
Invertebrates:
Arogos skipper
Buchholz's dart mouth
Cape Fear threetooth
Croatan crayfish
Magnificent rams-horn
Rare skipper
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
13
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
3.0 REFERENCE REACHES
Reference reaches were utilized on which the morphological characteristics were
measured to determine a range of values for the stable dimension, pattern, and profile of
the proposed channel. The following sections include a detail of three of the reference
reaches that were used for design of the restoration plan for the Middle Branch of
Hewlett's Creek. The reference reaches used along with the bankfull area, and current
constraints as the base for the preliminary design.
3.1 JOHANNAH CREEK
The Johannah creek has a drainage area of 1.18 square miles. Angela Moreland of the
NCSU Water Quality group completed the stream survey of Johannah creek in the
summer of 2001. The stream had a bankfull channel width of 10.4 feet and a bankfull
mean depth of 0.8 feet. Johannah Creek is a C5 stream type from Rosgen Classification
system. The morphological characteristics of this reference stream are included in Table
2.
3.2 PANTHER BRANCH
The Panther branch has a drainage area of 1.69 square miles. Angela Moreland of the
NCSU Water Quality group completed the stream survey of Panther branch in the
summer of 2001. The stream had a bankfull channel width of 11.5 feet and a bankfull
mean depth of 1.6 feet. Panther Branch is an E5 stream type from Rosgen Classification
system. The morphological characteristics of this reference stream are included in Table
2.
3.3 BATORORA BRANCH
Angela Moreland of the NCSU Water Quality group completed the stream survey of
Batorora branch in the summer of 2001. The stream had a bankfull channel width of 15.5
feet and a bankfull mean depth of 1.5 feet. Batorora Branch is an E5 stream type from
Rosgen Classification system. The morphological characteristics of this reference stream
are included in Table 2.
15
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Table 2. Middle Branch of Hewlett's Creek Morphology (Existing,
Design, and Reference)
Parameter Existing Reference Reference Reference Design
Reach Name Hewlett Panther Johannah Batorora Hewlett
Bankfull XSEC Area, Abkf (ft) 30 17.9 8.6 23.9 30
Bankfull Width, Wbkf (ft) 20 11.5 10.4 15.5 19
Bankfull Mean Depth, Dbkf (ft) 1.5 1.6 0.8 1.5 1.6
Width to Depth Ratio, W/D (ft/ft) 13.3 7.4 12.6 10.1 12
Entrenchment Ratio, Wfpa/Wbkf (ft/ft) 2 17.4 19.2 12.9 3
Bank Height Ratio, Dtob/Dmax (ft/ft) 2.0 1 1 1 1
Min Bkf Max Depth, Dmax (ft) 1.6 --- --- - 2.1
Max Bkf Max Depth, Dmax (ft) 1.9 --- --- --- 2.8
Min Bkf Max Depth, Dmax/Dbkf 1.1 1.6 1.3 1.4 1.3
Max Bkf Max Depth, Dmax/Dbkf 1.3 1.8
Min Meander Length, Lm (ft) 100 --- --- --- 86,
Max Meander Length, Lm (ft) 280 --- --- --- 171
Min Meander len Ratio, Im/Wbkf 5 2.3 1.9 4.1 4.5
Max Meander Len Ratio, Lm/Wbkf 14 9.1 5.1 6.8 9
Min Radius of Curvature, Rc (ft) 60 --- --- --- 34
Max Radius of Curvature, Rc (ft) 80 --- --- --- 49
Min Rc Ratio, Rc/Wbkf 3 0.5 0.9 0.7 1.8
Max Rc Ratio, Rc/W bkf 4 1.5 2.3 2.6 2.6
Min Belt Width, Wblt (ft) 25, --- --- --- 42
Max Belt Width, Wblt (ft) 40 --- --- --- 76
Min MW Ratio, Wblt/Wbkf (ft) 1.3 1.9 1.3 2.9 2.2
Max MW Ratio, Wblt/Wbkf (ft) 2 8.7 4.4 4.5 4
Sinuosity, K 1.05 1.2 1.2 1.2 1.2
Valley Slope, Sval (ft/ft) .0026 .0040 .0026 .0061 .0026
Channel Slope, Schan=SvaVK (ft/ft) .0025 .0033 .0021 .0051 .0021
Pool Slope, Spool (ft/ft) 0 --- - - 0
Pool Slope Ratio, Spool/Schan 0 0 0 0
Min Pool Depth, Dpool (ft) 1.7 --- - - 2.4
Max Pool Depth, Dpool (ft) 2 --- --- --- 3.0
Min Pool Depth Ratio, Dpool/Dbkf 1.1 1.6 1.9 2 1.5
Max Pool Depth Ratio, DpooVDbkf 1.3 2
Min Pool Width, Wpool (ft) 21 --- --- --- 19
Max Pool Width, Wpool (ft) 25 --- - - 22.8
Min Pool Wid Ratio, Wpool/Wbkf 1.1 1 1.2 0.9 1
Max Pool Wid Ratio, Wpool/Wbkf 1.3 1.2
Min Length Pool Spacing, Lps (ft) 40 --- - - 57
Max Length Pool Spacing, Lps (ft) 220 --- --- --- 114
Min Pool Spacing Ratio, Lps/Wbkf 2 1.3 1.2 1.7 3
Max Pool Spacing Ratio, Lps/Wbkf 11 5.7 3.8 3.9 6
16
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.0 STREAM CHANNEL DESIGN
This restoration will classify as a Priority 2 restoration (Rosgen, 1997). The floodplain
will be re-established to fit the existing or slightly raised stream profile. The grade of the
stream will be raised in some areas and a floodplain will be established at the new
bankfull elevation. Table 3 describes and summarizes the four priorities of incised river
restoration (Rosgen, 1997). The proposed stream restoration will restore the natural
meander pattern, modify channel cross-section restore bedform, improve sediment
transport capacity, enhance habitat, and re-establish a floodplain for the stream.
The design was based upon Dave Rosgen's natural channel design methodology. As
described in Section 3.0, reference reaches were utilized on which the morphological
characteristics were measured to determine a range of values for the stable dimension,
pattern, and profile of the proposed channel. The measured and proposed morphological
characteristics are shown in Table 2.
A conceptual design was developed from the range of values listed in Table 2. This
stream restoration project will result in approximately 3,600 restored linear feet (as
measure from the thalweg) of The Middle Branch of Hewlett's Creek. The plan view of
the proposed restoration design can be seen in Figures 4, 5 and 6.
17
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Table 3. Priorities, Description and Summary for Incised River Restoration
DESCRIPTION METHODS ADVANTAGES DISADVANTAGES
PRIORITY 1 Re-establish channel on Re-establishment of 1) floodplain re-
Convert G and/or F previous floodplain using relic floodplain and stable establishment could cause
stream types to C and/or channel or construction of channel: flood damage to urban
E at previous elevation new bankfull discharge 1) reduces bank height and agricultural and industrial
w/floodplain channel. Design new channel streambank erosion development.
for dimension, pattern and 2) reduces land loss 2) downstream end of
profile characteristic of stable 3) raises water table project could require grade
form. Fill in existing incised 4) decreases sediment control from new to
channel or with discontinuous 5) improves aquatic and previous channel to prevent
oxbow lakes level with new terrestrial habitats head-cutting.
floodplain elevation. 6) improves land
productivity, and
7) improves aesthetics.
PRIORITY 2 If belt width provides for the 1) decreases bank height 1) does not raise water
Convert G and/or F minimum meander width ratio and streambank erosion table back to previous
stream types to C or E. for C or E stream types, 2) allows for riparian elevation
Re-establishment of construct channel in bed of vegetation to help stabilize 2) shear stress and velocity
floodplain at existing or existing channel, convert banks higher during flood due to
higher, but not at existing bed to new 3) establishes floodplain to narrower floodplain
original level floodplain. If belt width is too help take stress of channel 3) upper banks need to be
narrow, excavate streambank during flood sloped and stabilized to
walls. End-hall material or 4) improves aquatic habitat reduce erosion during
place in streambed to raise 5) prevents wide-scale flood.
bed elevation and create new flooding of original land
floodplain in the deposition. surface
6) reduces sediment
7) downstream grade
transition for grade control
is easier.
PRIORITY 3 Excavation of channel to 1) reduces the amount of 1) high cost of materials
Convert to a new stream change stream type involves land needed to return the for bed and streambank
type without an active establishing proper river to a stable form. stabilization
floodplain, but dimension, pattern and 2) developments next to 2) does not create the
containing a floodprone profile. To convert G to B river need not be re-located diversity of aquatic habitat
area. Convert G to B stream involves an increase in due to flooding potential 3) does not raise water
stream type, or F to Be width/depth and entrenchment 3) decreases flood stage for table to previous levels.
ratio, shaping upper slopes the same magnitude flood
and stabilizing both bed and 4) improves aquatic
banks. A conversion from F habitat.
to Be stream type involves a
decrease in width/depth ratio
and an increase in
entrenchment ratio.
PRIORITY 4 A long list of stabilization 1) excavation volumes 1) high cost for
Stabilize channel in materials and methods have reduced stabilization
place been used to decrease stream 2) land needed for 2) high risk due to
bed and bank erosion, restoration is minimal excessive shear stress and
including concrete, gabions, velocity
boulders and bio-engineering 3) limited aquatic habitat
methods depending on nature of
stabilization methods used.
Source: Rosgen, 1997, "A Geomorphological Approach to Restoration of Incised Rivers"
18
CITY OF WILMINGTON STORMWATER POND
3
.I
'i
ST

1.) Area shall be graded smooth upon completion of earthwork activities, with a
slope toward the storm water pond and a maximum side slope of 3:1
2.) Area shall be stabilized with temporary seed upon completion of earthwork
3.) Area shall be sprigged with Bermuda grass variety between May 15th and
June 15th, the contractor shall coordinate with the golf course superintendent
LEGEND
CROSS VANE ' CART PATH
*
-

•9ee Deto1 IJ (C-B) 'See Deta? IS (C-B)
LOG VANE i CULVERT CROSSING

'See Detoil TI (C-8) -See Oetol 7 (C-7)
ROOT WADS ` RETAINING WALL
?.Y.b
'See Detol ICI ([-8 'See DetoT 16 C-9)
NOTE: Structure placement on Plan Sheets
are for location only. Actual placement shall
be directed by Resident Engineer
DETAIL
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1 DATE
08/08/2001
PROJECT NO.
FILENAIAE HENLETT.DWG
SHEET NO.
C-2
DRAWNG No.
??r1

CU RVE TABLE
CURVE LENGTH RADIUS
C- 1 69.6 39.5
C- 2 22.3 32.0
G- 3 49.8 34.0
C- 4 25.0 34.0
C- 5 43.3 39.0
C- 6 72.1 420
C- 7 65.1 36.0
C- 6 69.2 420
C- 9 38.9 36.0
C- 10 29.0 40.0
C- 11 5117 43.0
C- 12 43.7 35.0
C- 13 38.8 33.0
C- 14 38.1 34.0

NOTE: The listed Radius of Curvatures are
measured from the stream centerline.
Actual Radius of Curvatures maybe
adjusted by Resident NCSU Engineer
i
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11
LINE TABLE
LINE LENGTH BEARING NORTHING EASTING
L- 1 25.5 N 711'58' 181485 2332881
L- 2 31.9 N57'4o'33'W 181518 2332892
L- 3 31.9 N1 58'53'W 151554 2332951
L- 4 53.9 N3819-54' 151507 2332952
L- 5 3S5 N44MV1 -W 161891 2332983
L- 6 19.4 N7325.15 161750 2332973
L- 7 37.5 NZ1D8'04'W 151832 2333028
L- 8 41.9 N7 1'23'W 161914 2333054
L- 9 29.8 N2127'35'E 161927 2333125
L- 10 42.4 N70'O3'16' 151972 2333159
L- 11 35.9 N1150'16'W 182068 2333276
L- 12 30.3 N75 7'44 162150 2333293
L- 13 24.4 NI 2'06'09-W 162192 2333344
L- 14 31.7 N70'4847'E 1672445 1 2333357
NOTE: The listed Northing and Easting Columns
represent the head of the appropriate riffle section
along the centerline of the stream. Actual riffle
starting locations, bearing and lengths maybe adjusted
by Resident NCSU Engineer

V STREAM (SREV)
S
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GRADING Led TS OF CONSTRVCnON
PERMANENT EASEMENT /
LEGEND
CROSS VANE * CART PATH
*
-
'See Detal 13 (C-8) 'See Detail 15 (C-8)
LOG VANE CULVERT CROSSING
`
'see 000 11 (C-8) •See Detal 7 (C-7)
ROOT WADS * RETAINING WALL
f`4s4_a A
G
'See Detae 12 C-8) -See Det.] 16 (C-9
NOTE: Structure placement on Plan Sheets
ore for location only. Actual placement shall
be directed by Resident Engineer
,1?Fr1J'< cXO ?• yo
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SEE DETAIL Y (C-7)
SCALE 1" = 40'
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DATE
08/08/2004
PROJECT NO.
FILENAME HEM.ETT.DWG
SHEET NO.
C-3
DRAWING NO
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GRADING LIMITS Or CONSTRUCTION
PERMANENT EASEMENT
}
00
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SEE DETAIL 9 (C-7)
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sp CE R
SEE DETAL 7 (C-7)
CU RVE TABLE
CURVE LENGTH RADIUS
C- 15 37.3 42.0
C- 18 3510 40.0
C- 17 57.8 34.0
C- 18 50.1 30.0
C- 19 87.7 30.0
C- 20 88.4 30.0
C- 21 27.2 35.0
C- 22 17.0 38.0
C- 23 30.0 35.0
C- 24 328 38.0
C- 25 34.2 35.0
C- 28 44.9 37.0
C- 27 34.8 3ao
C- 28 59.4 39.0
NOTE: The listed Radius of Curvatures ore
measured from the stream centerline.
Actual Radius of Curvatures maybe
adjusted by Resident NCSU Engineer
CLAY PLUG
SEE DETAIL 9 (C-7)
¢ STREAM (SREV

LINE TABLE
LINE LENGTH BEARING NORTHING EASTING
_
L- 15 27.1 1 '44•W 182287 2333402
L- 18 57.8 NM24'3-rE 182347 2333411
L- 17 33.5 N 09"'50-W 182411 2333472
L- 18 34.4 N 5 '1 'W 182482 2333500
L- 19 331 N3 'W 182320 2333582
L- 20 21.7 N '4 ' 'W 182587 2333583
L- 21 28.8 182813 2333841
L- 22 25.2 N 182883 2333830
L- 23 18.5 '1 ' 182788 2333852
L- 24 20.2 N 'W 182788 2333884
L- 25 2&8 N 182777 2333938
L- 28 28.1 54D4' 'W 182798 2373991
L- 27 30.1 N494 ' 182783 2334043
L- 28 29.0 'W 182800 2334110
L- 29 29.8 N 182776 233418}
NOTE: The listed Northing and Easting Columns
represent the head of the appropriate riffle section
along the centerline of the stream. Actual riffle
starting locations, bearing and lengths maybe adjusted
by Resident NCSU Engineer
REPLACEMENT CARY PATH
SEE DETAIL 15 (C-5)
LEGEND
CROSS VANE ' CART PATH
*
-

•See Deto1 13 (C-8) •Sb Deena 15 (c-8)
LOG VANE CULVERT CROSSING

'See Deto1 11 C-8 •See Detoa 7 (C-7
ROOT WADS * RETAINING WALL
11 `"

'See Deto1 12 (C-8 •See Detdl 16 C-9
NOTE: Structure placement on Plan Sheets
are for location only. Actual placement shall
be directed by Resident Engineer
SCALE 1" = 40'
40 0 40 80

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DATE
08/08/2004
PROJECT NO.
FILENAME
MEYAETT.ONC
SHEET NO.
C
-4
DRAWING NO
t \ /
GRAD MG LOTS OF CONSTRUCTION
PERMANENT EASEMENT
23+
GE f243
)
: DUAL 7 (C-7)
CU RVE TABLE
CURVE LENGTH RADIUS
C- 15 37.3 42.0
C- 16 35.0 40.0
C- 17 57.5 34.0
C- 16 55.1 30.0
C- 19 67.7 30.0
C- 20 68.4 30.0
C- 21 27.2 35.0
C- 22 17.0 36.0
C- 23 30.0 35.0
C- 24 37-6 35.0
C- 25 34.2 35.0
C- 25 44.9 3790
C- 27 34.6 37.0
C- 26 59.4 79.0
NOTE: The listed Radius of Curvatures are
measured from the stream centerline.
Actual Radius of Curvatures maybe
adjusted by Resident NCSU Engineer
q STREAM (SREV)
LINE TABLE
LINE LENGTH BEARING NORTHING EASTING
L- 15 27.1 N09-15'44'W 182287 7.1 402
L- 16 57.8 N,"'24%5rE 182347 2333411
L- 17 33.5 N 50'W 162411 2333472
L- 18 34.4 N85'0'1 'W 162482 2737500
L- 19 33.1 NJ '14'W 162520 537582
L- 20 21.7 N 1'4 'W 182587 2333583
L- 21 25.8 N 8 'W 182813 2333841
L- 22 25.2 182563 2333830
L- 23 18.5 N79 'O ' 162788 2333852
L- 24 28.2 N59-25'00'W 182788 2333884
L- 25 28.6 N50 162M 2333938
L- 28 28.1 N 4M' 'W 162796 2333991
L- 27 30.1 N49'4 '05' 162783 2334045
L- 28 29.0 N 51'5 'W 162800 2334110
L- 29 29.6 N57'I ' 182778 2734187
NOTE: The listed Northing and Eosting Columns
represent the head of the appropriate riffle section
along the centerline of the stream. Actual riffle
starting locations, bearing and lengths maybe adjusted
by Resident NCSU Engineer

LEGEND
CROSS VANE * CART PATH
*
-
•See Nt.1 13 (C-B •See Oe1ad 15 (C-B
LOG VANE CULVERT CROSSING

'See Delal 11 (C-8) -See Detail 7 (C-0
ROOT WADS * RETAINING WALL

F Tt
'See De1a0 12 (C-B •See Det.l 16 C-9
NOTE: Structure placement on Plan Sheets
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Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Existing pattern measurements were taken from the topographic mapping. A stable
pattern will be established by establishing new meanders along the channel. This will be
achieved by introducing meanders into the stream with radius of curvatures and lengths
based on reference reach data and the existing constraints. The maximum stream length
and sinuosity has been designed into the new channel based on the reference data and
project constraints. Introduction of these meanders will improve habitat while lowering
slope and shear stress.
4.1.3 Bedform
The existing bedform along the Middle Branch of Hewlett's Creek is in poor condition.
Long, straight sections of the channel consist of predominantly run bedform features. The
design channel will incorporate ripples and pools to provide bedform common to E5
stream types. Pools will be located in the outside of meander bends with riffles in the
inflection points between meanders. The ripples will have a thalweg depth of 1.6 feet
while the pools will be deeper with a maximum depth of 3.0 feet. A graph of the
proposed profile can be seen in Figure 8. The profile may be adjusted slightly during the
final design phase of the project.
Cross-vanes will be utilized as grade control structures and to tie the relocated sections
back into the existing channel. The cross vanes will be constructed out of natural
materials such as wood and some boulders.
The existing pool-to-pool spacing is impaired in areas due to tight meander geometry.
The proposed spacing is 57 to 114 feet, which is within the range of 3 and 6 bankfull
widths as determined from the reference reach data. To accomplish this, pools will be
realigned or constructed such that they will be located in the outside of the meander
bends. Bedform will also be addressed through the strategic placement of natural material
structures such as cross vanes, root wads and large woody debris. Modifications to the
bedform will provide stability and habitat to the channel.
4.1.4 Riparian Areas
A riparian zone will be created around the new proposed stream channel to enhance both
aquatic and terrestrial habitat as well as stabilize the stream channel. The riparian zone
will extend at least 15 feet on either side of the channel from the top of bank. Were ever
possible the riparian zone will extend at least 25 feet on either side of the channel. These
areas will be planted with appropriate riparian vegetation as described in Section 6.0
Habitat Restoration. The riparian zone is limited by the urban constraints and the
constraints of an active golf course that includes play that cross the stream channel.
23
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
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Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.2 SEDIMENT TRANSPORT
A stable stream has the capacity to move its sediment load without aggrading or
degrading. The total load of sediment can be divided into bed load and wash load. Wash
load is normally composed of fine sands, silts and clay and transported in suspension at a
rate that is determined by availability and not hydraulically controlled. Bed load is
transported by rolling, sliding, or hopping (saltating) along the bed. At higher discharges,
some portion of the bed load can be suspended, especially if there is a sand component in
the bed load. Bed material transport rates are essentially controlled by the size and nature
of the bed material and hydraulic conditions (Hey 1997).
Critical dimensionless shear stress can be found using Shield's Curve and surface particle
sample from a representative riffle in the reach. A riffle bed surface pebble count was
taken at a riffle on the Middle Branch of Hewlett's Creek. The riffle bed surface d50 was
then calculated to be 0.06 mm. The shear stress placed on the sediment particles is the
force that entrains and moves the particles, in a given channel geometry. From Shields
curve the shear stress that entrains and moves particles in this stream based on the d50 is
.00251bs/sqft.
Wetted perimeter was measured off of a CADD file of the typical riffle cross-section
drawn to scale. The wetted perimeter was measured to be 29 ft, while the cross-sectional
area was 30 sqft this produced a hydraulic radius of 1.03. The Slope for the used for the
shear stress calculation is 0.0023. The resultant shear stress for the proposed channel is
0.15 lbs/sgft, this shear stress is sufficient to move the d84 of the riffle bed material,
which is 0.15 mm. Shield's Curve predicts that this stream can move a particle that is, on
average, greater than 5 mm. Since the D84 was 0.15 mm and Shield's Curve predicts 5
mm, the proposed stream has the competency to move its bed load.
Sediment transport analysis was examined at the restoration site through the comparison
of existing and post restoration shear stress analysis. The existing channel does not
appear to be aggrading so it is implied that it is more capable of transporting its
watershed sediment load. Two existing shear stresses are examined and one restored
shear stress. Shear stress is approximated using the equation shear stress = density of
water times the hydraulic radius times the average water surface slope. Existing bankfull
shear stress is 0.233 lbs/sqft. The top of bank shear stress is 0.4541bs/sqft.
Post restoration, average water surface slope will be decreased and the floodplain will be
established adjacent to the bankfull channel thus lowering the top of bank shear stress
significantly. The post restoration bankfull shear and top of bank shear stress is 0.222
lbs/sgft. These calculations were confirmed with HEC-RAS modeling.
4.3 FLOODING ANALYSIS
This restoration site is not in a mapped FEMA regulatory floodway zone and therefore, is
not subject to FEMA regulations. NCSU design team has also received verification from
26
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
the City of Wilmington Division of Stormwater that this reach of Hewlett's Creek is not
FEMA mapped and does not have a recorded history of flood related incidents. Currently
there are no structures located in the adjacent areas that would be impacted by floodplain
alterations. The Priority 2 restoration of the stream will leave the stream's existing profile
elevations essentially the same. A new floodplain will be established so that the active
stream will be able to access it during larger storm events. Considering the type of
restoration it is assumed that for smaller events the water surface elevations along the
stream shall remain the same. During storms where the stream accesses the newly
establishment floodplain the new water surface elevations are expected to be lower than
the existing water surface elevations of storms of the same magnitude. The restoration
will create neither positive nor negative water surface elevation changes during the larger
storm events (greater than 25-year). HEC-RAS was used to analyze both existing and
proposed conditions after the design was finalized. Sheer stress and flood stages were
compared at various return intervals to evaluate the design.
4.4 STRUCTURES
Several different structures made of natural materials will be installed along the Middle
Branch of Hewlett's Creek. These structures include cross vanes, single vanes, and root
wads. Natural materials such rocks and root wads will be used to create these structures
from off-site sources and on-site sources.
4.4.1 Cross Vane
A cross vane structure serves to maintain the grade of the stream. The design shape is
roughly that of the letter "U" with the apex located on the upstream side at the foot of the
riffle. Footer rocks are placed in the channel bottom for stability. Rocks or logs are then
placed on these footer rocks in the middle of the channel at approximately the same
elevation as the ripple. On either side of the channel, rocks or logs are placed at an angle
to the stream bank, gradually inclining in elevation until they are located above the
bankfull surface directly adjacent to the stream bank. Water flowing downstream is
directed over the vane towards the middle of the channel. Rocks or a log placed at the
apex determine the bed elevation upstream. A cross vane is primarily used for grade
control and to protect the stream banks.
4.4.2 Root Wads
The objectives of these structure placements are as follows: (1) protect the stream bank
from erosion; (2) provide in-stream and overhead cover for fish; (3) provide shade,
detritus, terrestrial insect habitat: (4) look natural, and (5) provide diversity of habitats
(Rosgen 1996). A footer log and boulder are placed on the channel bottom abutting the
stream bank along an outside meander that will provide support for the root wad and
additional stability to the bank. A large tree root wad is then placed on the stream bank
with additional boulders and rocks on either side for stability. Flowing water is deflected
away from the bank and towards the center of the channel.
27
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.4.3 Single Vane
A single vane structure serves to maintain the pattern of the stream. Footer rocks are
placed in the channel bottom for stability. Rocks or logs are then placed on these footer
rocks in the middle of the channel at approximately the same elevation as the ripple. On
either side of the channel, rocks or log is placed at an angle to the stream bank, gradually
inclining in elevation until they are located above the bankfull surface directly adjacent to
the stream bank. Water flowing downstream is directed over the vane towards the middle
of the channel. A single vane is primarily used to turn the stream flow and control and to
protect the stream banks.
Specific location of these structures will be determined during final design.
28
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
5.0 HABITAT RESTORATION
The restoration plan requires the establishment of riparian vegetation at the site. The
proposed vegetation is described in the following sections.
5.1 VEGETATION
Vegetation that develops a quick canopy, has an extensive root system, and a substantial
above-ground plant structure is needed to help stabilize the banks of a restored stream
channel in order to reduce scour and runoff erosion. In natural riparian environments,
pioneer plants that often provide these functions are alder, river birch, silky dogwood,
and willow. Once established, these trees and shrubs create an environment that allows
for the succession of the other riparian species including ashes, black walnuts, red
maples, sycamores, oaks, and other riparian species.
In the newly restored stream channel, revegetation will be vital to help stabilize the
stream banks and establish a riparian zone around the restored channel. Revegetation
efforts on this project will emulate natural vegetation communities found along relatively
undisturbed stream corridors. To quickly establish dense root mass along the channel
bank, a native grass mixture will be planted on the streambed and bank. Shrubs will be
utilized on the stream bank and along the floodplain to provide additional root mass.
Extra care will be given to the outside of the meander bends to ensure a dense root mass
in those areas of high stress. Coir matting or similar material will be used to provide
erosion protection until vegetation can be established. Along the tops of the channel
banks, trees, shrubs and a native grass mixture will be planted.
A mixture of seeds, live stakes, bare root, as well as balled in burlap nursery stock, some
2 "- 4" caliper tree and transplants will be used to stabilize the banks. Proposed species
to be planted included, but are not limited to:
Trees
Blackcherry (Prunus serotina)
Blackgum (Nyssa sylvatica)
Loblolly Bay (Gordonia lasianthus)
River Birch (Betula nigra)
Sugarberry (Celtis laevigata)
Shrubs
American hornbeam (Carpinus caroliniana)
Fetter bush (Lyonia lucida)
Inkberry (Ilex glabra)
Marsh mallow (Hibiscus moscheutos)
Silky dogwood (Cornus amomum)
Sweet pepperbush (Clethra alnifolia)
Virginia willow (Itea virginica)
29
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Herbs- Permanent seed mixture
Deertongue (Panicuin clandestinum)
Purple love grass (Ergrostis spectabilis)
Switch Grass (Panicum virgatum)
Tussock sedge (Carex stricta)
Other herbaceous vegetation
Dwarf spike-rush (Eleocharis parvula)
Ironweed (Vernonia noveboracensis)
Jack-in-the-pulpit (Arisaema triphyllum)
Woody vegetation will be planted between February and May to allow plants to stabilize
during the dormant period and set root during the spring season. In the areas where
invasive and exotic species are located, during construction and monitoring control by
removal or appropriate herbicides will be implemented to prevent competition with the
revegetation efforts.
5.2 RIPARIAN BUFFERS
At least three different types of riparian buffers will be employed to vegetate the restored
channel. All buffers will use plants native to the coastal plain region of North Carolina.
In areas where the fairways cross the stream channel, vegetation will be kept to a minimal
height so as not to obstruct views and play within the crossing. The areas along the city
sewer line (within approximately 10' to either side of the utility) will be planted with
vegetation having shallow (limited) root structure so that the sewer line and access to it
shall not be impacted or impeded. The remaining areas will be planted with native trees,
shrubs, grasses and other herbaceous vegetation in order to restore natural coastal plain
plant communities. Proposed species to be planted include but are not limited to those
listed in the above section
5.2.1 Temporary Seeding
A temporary seed mixture will be applied to all disturbed areas immediately after
construction activities have completed. This temporary seed mixture will provide erosion
control until permanent seed can become established. Permanent seed will be native to
the coastal region of North Carolina.
30
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
6.0 MONITORING
6.1 STREAM CHANNEL
Monitoring of the stability of the channel is recommended to occur approximately 6
months after restoration is complete or after bankfull (or greater) events and should
continue annually for a period of 3 to 5 years. Monitoring practices may include, but are
not limited to, installing bank erosion pins and a toe pin, monumented cross-sections,
scour chains, macroinvertebrate studies, longitudinal profiles, conducting the bank
erosion hazard rating guide and establishing photo reference points. The purpose of
monitoring is to determine bank stability, bed stability, morphological stability and
overall channel stability. Table 4, below, can be used for selecting practices.
Table 3. - Stream Monitoring Practices
PRACTICE STABILITY ASSESSMENT
Bank Erosion Pins with Toe Pin -Lateral or bank stability
Monumented Cross-Section -Vertical or bank stability
-Lateral or bank stability
Scour Chains -Vertical or bed stability
-Scour depth fora articular storm
Scour Chain w/ Monumented
Cross-Section -Vertical or bed stability
-Sediment transport relations
-Biological interpretations
Longitudinal Profile -Channel profile stability
Bank Erosion Hazard Guide -Bank erosion potential
Photo Reference Points -Overall channel stability
Macroinvertebrate -Biological indication of water quality
6.2 VEGETATION
Prior to planting, the site will be inspected and checked for proper elevation and
suitability of soils. Availability of acceptable, good quality plant species will be
determined. The site will be inspected at completion of planting to determine proper
planting methods, including proper plant spacing, density, and species composition.
Competition control will be implemented if determined to be necessary during the early
stages of growth and development of the tree species. Quantitative sampling of the
vegetation will be performed between August 1 and November 30 at the end of the first
year and after each growing season until the vegetation criteria is met.
In preparation for the quantitative sampling, 50 by 50 feet (0.05-acre) vegetative plots
will be established in the reforested area. Plots will be evenly distributed throughout the
31

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
site. For each plot, species composition and density will be reported. Photo points will be
taken within each zone. Monitoring will take place once each year for five years.
Success will be determined by survival of target species within the sample plots. At least
six different representative tree species should be present on the entire site. If the
vegetative success criteria are not met, the cause of failure will be determined and
appropriate corrective action will be taken.
6.3 MACROIN VERTEBRATES
A monitoring period of 3 to S years is commonly suggested to determine changes in
macroinvertebrate populations within a newly restored stream. The North Carolina
Wetlands Restoration Program will determine a macroinvertebrate monitoring policy.
32

Stream Restoration Plan
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
7.0 REFERENCES
Amoroso, J.L., ed. 1999. Natural Heritage Program List of the Rare Plant Species of
North Carolina. North Carolina Natural Heritage Program, Division of Parks and
Recreation, North Carolina Department of Environment and Natural Resources. Raleigh,
North Carolina.
Cowardin, L.M., V. Carter, F.C. Golet and E.T. LaRoe. 1979. Classification of Wetlands and
Deepwater Habitats of the United States. U.S. Fish and Wildlife Service, Office of
Biological Services, FWS/OBS-79/3 I. U.S. Department of the Interior, Washington, DC.
Choate, J.R., J.K. Jones, Jr., and C. Jones. 1994. Handbook of Mammals of the South-Central
States. Louisiana State University Press, Baton Rouge, Louisiana.
Doll, B. A., et al. 2000. Hydraulic Geometry Relationships for Urban Streams throughout the
Piedmont of North Carolina. American Water Resources Association.
Godfrey, R.K., and J.W. Wooten. 1979. Aquatic and Wetland Plants of Southeastern United States.
Monocotyledons. The University of Georgia Press, Athens, Georgia.
Godfrey, R.K., and J.W. Wooten. 1981. Aquatic and Wetland Plants of Southeastern United States.
Dicotyledons. The University of Georgia Press, Athens, Georgia.
Harrelson, Cheryl, C.L. Rawlins and John Potyondy. 1994. Stream Channel Reference Sites: An
Illustrated Guide to Field Technique. United States Department of Agriculture, Forest Service.
General Technical Report RM-245.
Hey, Richard and Dave Rosgen. 1997. Fluvial Geomorphology for Engineers. Wildland Hydrology,
Pagosa Springs, Colorado.
LeGrand, H.E., Jr. and S.P. Hall, eds. 1999. Natural Heritage Program List of the Rare
Animal Species of North Carolina. North Carolina Natural Heritage Program, Division of
Parks and Recreation, North Carolina Department of Environment and Natural
Resources. Raleigh, North Carolina.
NCDENR. "Water Quality Stream Classifications for Streams in North Carolina." Water Quality
Section. http:/Ih2o.enr.state.nc.us/wghome.htm] (16 July 2001).
Radford, A.E., H.E. Ahles and G.R. Bell. 1968. Manual of the Vascular Flora of the Carolinas. The
University of North Carolina Press, Chapel Hill, North Carolina.
Rosgen, Dave. 1997. A Geomorphological Approach to Restoration of Incised Rivers.
Wildland Hydrology. Proceedings of the Conference on Management of Landscapes
Disturbed by Channel Incision.
33

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Schafale, M. P. and A. S. Weakley. 1990. Classification of the Natural Communities of
North Carolina: Third Approximation. North Carolina Natural Heritage Program.
Raleigh, North Carolina
United States Department of Agriculture - Soil Conservation Service. December, 1977. "Soil
Survey of Guilford County, North Carolina." US Government Printing Office, Washington,
DC.
United States Fish and Wildlife Service. "Region 4, Southeast Region/Endangered Species." North
Carolina Ecological Services. http://nc-es.fws.gov/ (August 2001).
USDA, NRCS. 2001. The PLANTS Database, Version 3.1 (http://plants.usda.gov). National Plant
Data Center, Baton Rouge, LA 70874-4490 USA.
34
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.2.5 Wildlife Observations
Wildlife and signs of wildlife were noted during on-site visits, however, a formal wildlife
survey was not performed. Tracks of white tailed deer (Odocoileus virgin ianus) and
raccoon (Procyon Iotor) were observed along the stream banks. A variety of birds were
observed in the thickets and shrubs surrounding the stream channel and forest, including:
various sparrows.
2.2.5.1 Possible Invasive Wildlife
The following species were identified during site visits to the Middle Branch of Hewlett's
Creek; Asian tiger mosquito (Aedes albopictus), Bullfrog (Rana catesbeiana) (auditory
identification), European gypsy moth (Ly»nantria dispar), and European starling (Stunuts
vulgaris). The bullfrog is listed based on auditory identification by one of the project
researchers. The gypsy moth is listed based on visual identification of nests. The
mosquito and starling are listed due to their ubiquitous nature.
2.2.6 Endangered Species
The NCSU design team has not identified endangered plant or animal species or any such
habitat that would support the endangered species listed in this section. The NCSU
design team has made multiple visits to the Pine Valley Country Club and the restoration
site. Below is a list obtained from Natural Heritage, of the endangered of concern for
New Hanover County.
2.2.6.1 Endangered Flora
Vascular Plants:
Cooley's meadowrue
Rough-leaved loosestrife
Seabeach amaranth
Bog St. John's-wort
Carolina asphodel
Carolina bishopweed
Carolina beaksedge
Chapman's sedge
Coastal golden rod
"Dune bluecurls"
Pickering's dawnflower
Pondspice
Sandhills milkvetch
Savanna indigo-bush
Spiked medusa
Spring-flowering goldenrod
Tough bumelia
Endangered
Endangered
Threatened
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
12

I-1EV tom. I V E
SFP S 2004
NC ECOSYSTEM
ENHANCEMENT PROGRAM
Stream Restoration Plan
Hewlett's Creek
New Hanover County, North Carolina
i co item _?.
cii e e
1739.= ' .

August 31, 2004
Biological8.
Agricultural Engineering
Biological & Agricultural Engineering
Weaver Labs, Campus Box 7625
North Carolina State University
Raleigh, North Carolina 27695
WETLANDS 1401 GROUP
SEP 0 7 2004
WATER QUALITY SECTION

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
TABLE OF CONTENTS
1.0 INTRODUCTION ............................................................1
1.1 PROJECT DESCRIPTION ..........................................2
1.2 GOALS AND OBJECTIVES ........................................2
1.3 STREAM SURVEY METHODOLOGY ...........................2
1.3.1 Stream Delineation - Classification .........................4
1.3.2 Bankfull Verification ..........................................4
2.0 EXISTING CONDITIONS ...................................................6
2.1 WATERSHED ....................................................... ..6
2.1.1 General Description of the Watershed .................... ..6
2.1.2 Surface Waters Classification ................................6
2.1.3 Soils of the Watershed .........................................6
2.1.4 Land Use of the Watershed ................................. ..8
2.2 RESTORATION SITE ................................................8
2.2.1 Site Description .............................................. ..8
2.2.2 Existing Stream Characteristics ............................ ..8
2.2.3 Soils of the Restoration Site ... . ............................ ..9
2.2.4 Terrestrial Plant Communities .............................. ..9
2.2.4.1 Managed Land ..................................... .12
2.2.4.2 Bottomland Forrest ............................... 12
2.2.4.3 Upland Hardwood Forest ........................ 12
2.2.4.4 Possible Invasive Flora ........................... 12
2.2.5 Wildlife Observations ........................................13
2.2.5.1 Possible Invasive Wildlife .......................... 13
2.2.6 Endangered Species ........................................... 13
2.2.6.1 Endangered Flora .................................. 13
2.2.6.1 Endangered Fauna ................................. 14
3.0 REFERENCE REACHES ...................................................15
3.1 JOHANNAH CREEK ...............................................15
3.2 PANTHER BRANCH ...............................................15
3.3 BATORORA BRANCH ............................................15
4.0 STREAM CHANNEL DESIGN ...........................................17
4.1 RESTORATION TECHNIQUES .................................22
4. 1.1 Dimension ......................................................22
4.1.2 Pattern ..........................................................22
4.1.3 Bedform ........................................................23

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.1.4 Riparian Areas ......... .......................................23
4.2 SEDIMENT TRANSPORT .. .......................................26
4.3 FLOODING ANALYSIS .... .......................................26
4.4 STRUCTURES ................ .......................................27
4.4.1 Cross Vane .............. .......................................27
4.4.2 Root Wads .............. .......................................27
4.4.3 Single Vanes ...................................................28
5.0 HABITAT RESTORATION ...............................................29
5.1 VEGETATION .......................................................29
5.2 RIPARIAN BUFFERS ..............................................30
5.2.1 Temporary Seeding ..........................................30
6.0 MONITORING ............................................................... 31
6.1 STREAM CHANNEL ...............................................31
6.2 VEGETATION .......................................................31
6.3 MACROINVERTEBRATES .......................................32
7.0 REFERENCES ...............................................................33
LIST OF TABLES
Table 1. Bank Erosion Potential ............................................... 10
Table 2. Middle Branch of Hewlett's Creek Morphology .................16
Table 3. Priorities, Desc. & Summary for Incised River Restoration... 18
Table 4. Stream Monitoring Practices .......................................31
LIST OF FIGURES
Figure 1 Site Location ............................................................3
Figure 2 Watershed Arial ...................................................... ..7
Figure 3 Soils Map .............................................................. 11
Figure 4 Hewlett's Creek Restoration Plan .................................. 19
Figure 5 Hewlett's Creek Restoration Plan ................................. 20
Figure 6 Hewlett's Creek Restoration Plan .................................. 21
Figure 7 Typical Cross-Sections .............................................. 24
Figure 8 Proposed Longitudinal Profile ...................................... 25
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
1.0 INTRODUCTION
The North Carolina Wetlands Restoration Program (NCWRP) has identified The Middle
Branch of Hewlett's Creek as a potential stream restoration site. Hewlett's Creek drains
into the Greenville Sound, the Middle Branch of Hewlett's creek (NCDWQ Stream Index
Number 18-87-26 SA HQW) is located on urban land in the southeast corner of
Wilmington in New Hanover County, North Carolina (Figure 1).
Arcadis first identified Hewlett's Creek as a potential restoration site in a feasibility
report to NCWRP. NCSU is completing the design and will conduct construction
oversight of the restoration of the middle branch of Hewlett's Creek. The portion of
Hewlett's creek that is being evaluated for restoration is within the property boundaries
of the Pine Valley Country Club. The Country Club Membership met on March 17`h of
2003 and voted to allow WRP to fund a restoration project focused on the Middle Branch
of Hewlett's Creek.
The Middle Branch of Hewlett's Creek has areas of significant active bank erosion
throughout the proposed project limits. There is evidence of historic straightening and
degradation resulting from this straightening. Thinning and removal of riparian
vegetation has also accelerated the degradation process. The incised condition of the
existing channel is accelerating the erosion process by forcing the channel to contain
larger then bankfull storm events.
The restoration site is located entirely within the property boundaries of the Pine Valley
Country Club. A City of Wilmington 16" RCP sewer line is located along the entire
length of the reach that is being considered for restoration. The sewer line crosses the
existing channel twice within the reach and is offset from the existing channel by a range
of loft to 40ft. There are two power-lines and numerous irrigation lines for the golf
course within the project limits. The Middle Branch of Hewlett's Creek has many urban
constraints, but should be an excellent potential restoration site, and . ideal for
demonstration and education.
Restoration requires determining how far the stream has departed from its natural
stability and then, establishing the stable form of the stream under the current hydrologic
conditions within the drainage area. The proposed restoration will construct a stable
meander geometry, modify channel cross-sections, and establish a floodplain at the
existing stream elevation, thus, restoring a stable dimension, pattern and profile. This
restoration is based on analysis of current watershed hydrologic conditions, evaluation of
the project site, and assessments of stable reference reaches. The following
recommendations are included in this restoration plan:
• Form a stable channel with the proper dimension, pattern and profile.
• Establish a floodplain along the stream channel.
• Place natural material structures in the stream to improve stability and enhance
aquatic habitat.
• Stabilize stream banks with herbaceous and woody vegetation

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
1.1 PROJECT DESCRIPTION
The Middle Branch of Hewlett's Creek project site is located in Hanover County, North
Carolina. The project is fully contained within the property of one landowner (The Pine
Valley Country Club). The project reach is bounded by The Long Street Drainage Cannel
to the west (upstream) and a 78" RCP culvert for Robert E. Lee Drive to the east
(downstream) (Figure 1).
1.2 GOALS AND OBJECTIVES
This project has the following goals and objectives:
1. Restore 3527 linear feet of The Middle Branch of Hewlett's Creek (as measured
along the centerline)
2. Provide a stable stream channel that neither aggrades nor degrades while maintaining
its dimension, pattern, and profile with the capacity to transport its watershed's water
and sediment load.
3. Improve water quality and reduce further property loss by stabilizing eroding stream
banks.
4. Establish a new floodplain at the existing stream elevation.
5. Improve aquatic habitat with the use of natural material stabilization structures such
as root wads; log vanes, woody debris and a riparian buffer.
6. Provide aesthetic value, wildlife habitat and bank stability through the creation or
enhancement of a riparian zone.
1.3 STREAM SURVEY METHODOLOGY
The US Forest Service General Technical Report RM-245, Stream Channel Reference
Sites: An Illustrated Guide to Field Technique is used as a guide when taking field
measurements. Accurate field measurements are critical to determine the present
condition of the existing channel, conditions of the floodplain, and watershed drainage
patterns.
2
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New Hanover County, NC
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~ FIGURE 1
SITE LOCATION
RESTORATION PLAN
3
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
NCSU contracted with W. K. Dickson to conduct a topographic survey of the restoration
site in August 2002. This mapping along with field measurements taken by NCSU staff
was used to evaluate present conditions, new channel alignment and grading volumes.
Mapping also provided locations of property pins, large trees, vegetation lines, and
culverts, roads, utilities and elevation contours.
A windshield survey was also conducted to determine the existing conditions within the
watershed. The watershed is fully (>90%) developed with residential dwellings and has
an area of 1.5 sq. miles
During the site visits, three cross-sections were taken using standard differential leveling
techniques. These cross-sections were used to gather detail on the present dimension and
condition of the channel. Bankfull cross-sectional area was calculated using the bankfull
features, the bankfull area at riffles varied between 26 sqft to 31 sqft.
1.3.1 Stream Delineation Criteria - Classification
Dave Rosgen developed his stream classification system in order to accomplish the
following:
1) Predict a river's behavior
2) Develop specific hydraulic and sediment relationships for a given stream type and its
state
3) Provide a mechanism to extrapolate site-specific data. to stream reaches having
similar characteristics
4) Provide a consistent frame of reference for communicating stream morphology and
condition among a variety of disciplines and interested parties
The Rosgen Stream Classification System is based on five criteria: width/depth ratio,
entrenchment ratio, slope, sinuosity, and channel materials. All cross-sections were
classified using this system.
1.3.2 Bankfull Verification
The foundation of Dave Rosgen's classification system is the concept of bankfull stage,
which is the point of incipient flooding. The width/depth and entrenchment ratios
described above depend on the correct assessment of bankfull. If bankfull is incorrectly
determined in the field, the entire restoration effort will be based on faulty data. It is
important to verify the physical indicators observed in the field with either gage data or a
regional curve to ensure the correct assessment of the bankfull stage.
The bankfull stage is determined in the field using physical indicators. The following is a
list of commonly used indicators that define bankfull (Rosgen, 1996):
4
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
• The presence of a floodplain at the elevation of incipient flooding.
• The elevation associated with the top of the highest depositional feature (e.g. point
bars, central bars within the active channel). These depositional features are
especially good stage indicators for channels in the presence of terrace or adjacent
colluvial slopes.
• A break in slope of the bank and/or a change in the particle size distribution, since
finer material is associated with deposition by overflow, rather than deposition of
coarser material within the active channel.
• Evidence of an inundation feature such as small benches below bankfull.
• Staining of rocks.
The most dominant bankfull indicators along The Middle Branch of Hewlett's Creek are
high scour lines and breaks in slope along the backs of narrow point bars.
The most common method of verifying bankfull stage is to compare the field determined
bankfull stage with measured stages at a stream gauging station. This calibration can be
performed if there is a stream gage within the study area's hydro-physiographic region.
In un-gauged areas, Dave Rosgen recommends verifying bankfull with the development
of regional curves. The regional curves normally plot bankfull discharge (QbkD, cross-
sectional area, width, and depth as a function of drainage area. The cross-sectional areas
of The Middle Branch of Hewlett's Creek was plotted on the Urban, Coastal Regional
Curve of North Carolina developed by the North Carolina State University (NCSU)
Water Quality Group, 2003 to help verify bankfull stage.
Data obtained from field surveys was used to compute the morphological characteristics
shown on the graph. The cross-sectional area for The Middle Branch of Hewlett's Creek
plots along the trend line for the Urban Regional Curve. The bankfull cross-sectional area
for the design channel was determined from evaluating the North Carolina regional curve
relationships and comparing them to the reference reach sites surveyed near the
restoration site. HEC-RAS was used to verify the design cross-sectional area for the
project.
5
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.0 EXISTING CONDITIONS
2.1 WATERSHED
2.1.1 General Description of the Watershed
The Middle Branch of the Hewlett Creek is a second order stream, is located within the
Coastal Physiographic Province of the Cape Fear River Basin (USGS Cataloging Unit).
The watershed is located in the Southeast corner of Wilmington, in New Hanover
County, North Carolina. The headwaters of the project originate approximately 2 miles to
the north-northeast of the restoration site. From the headwaters, Hewlett flows for
approximately 4.0 miles before emptying into the Greenville Sound just southwest of
Masonboro inlet. The land use within the study is mixed residential, commercial, and an
18-hole golf course.
The watershed is approximately 1.5 square miles (Figure 2). The watershed is oriented
north to south bending to the east before the project site. The topography ranges from
gently sloping to flat with relatively flat former floodplain that has be detached by
channeling the stream the middle of the past century. Land surface elevations range from
approximately 30 to 55 feet above mean sea level.
2.1.2 Surface Waters Classification
Surface waters in North Carolina are assigned a classification by the DWQ that is
designed to maintain, protect, and enhance water quality within the state. Hewlett's Creek
?7-a b (NCDWQ Stream Index Number) is classified as a class SA HQW water body
(NCDENR, 2001). SA HQW water resources are waters protected for shellfish
propagation and survival, fishing, wildlife, secondary recreation, and agriculture.
2.1.3 Soils of the Watershed
The soils found in the watershed and adjacent to the stream can help determine the bed
and bank materials occurring in the stream. The Rosgen stream classification system uses
average particle size within the bankfull channel to help classify the stream. Knowing the
make up of the soils in the watershed, assists in understanding the anticipated bed-load
and sediment transport capacity of the stream.
Soils in upland areas within the watershed consist primarily of sand and urban complex
(draft maps and descriptions of the soils in the project area - New Hanover County Soil
Survey Office, Natural Resources Conservation Service [NRCS]). Depth to bedrock is
mapped as greater than 60 inches for the soils in the watershed. Soils in the side slopes
shoulders and summits of ridges include Baymeade-Urban Land complex 1 to 6 percent
slopes, and Rimini sand 1 to 6 percent slopes
6
The Middle Branch of Hewlett's Creek
New Hanover County, NC
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New Hanover County, NC North
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WATERSHED ARiAL
RESTORATION PLAN
7
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.1.4 Land Use of the Watershed
Land use within the watershed is predominately urban residential (Figure 2). Evaluation
of a 1998 aerial photo obtained from New Hanover Country reveals that approximately
90% of the watershed is built out with single home residential areas, roads, businesses
and golf courses, with the remaining being water detention and forested urban land that is
not likely to be developed. The total percent impervious cover in the watershed is
approximately 20%-30%
2.2 RESTORATION SITE
The following sections provide a description of existing site conditions. This includes the
current stream conditions, soils, and surrounding plant communities.
2.2.1 Site Description
The Middle Branch of Hewlett's Creek restoration site begins approximately 4.0 miles
from its confluence with the Greenville Sound. The project is located within the property
boundaries of The Pine Valley Country Club. The middle Branch of Hewlett's Creek
flows from the west to east through a 0 to 35-foot wide floodplain. The majority of the
floodplain is located on the within the ditched channel of Hewlett's creek. The
floodplain typically ends abruptly at the toe of the adjoining steep slopes. A former
terrace extends along the entire length of the project and is 75 to 300 feet wide the
majority of the terrace is presently being used as fairway for the adjacent golf course.
The channel has long straight reaches with very minimal meanders. Channel sinuosity for
the entire reach is 1.05. High banks and areas of severe bank erosion can be found
throughout the project reach.
The main factor in the degradation and impairment for the Middle Branch of Hewlett's
Creek appears to be historic straightening of the channel and removal of riparian
vegetation. Straightening has increased the channel slope and decreased the stream
sinuosity. Erosion has caused increased sediment supply and channel widening. This has
combined to lead to the development of central bars in several straight sections of the
channel. Further development of central bars will increase erosion and lateral migration
of the channel.
2.2.2 Existing Stream Characteristics
Field surveys of the existing stream channel and site were conducted in August 2002.
The Middle Branch of Hewlett's Creek Restoration Site can be typically defined as a
predominantly straight channel with poor habitat. Stream banks are steep with areas of
active erosion. Long straight sections of the channel have central bars forming; indicating
the channel is over-wide. Instead of focusing the flow along the thalweg, the central bars
deflect the stream-flow toward the banks and accelerate bank erosion.
8
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
flow toward the banks and accelerate bank erosion.
Riffle bankfull widths range from 24 to 30 feet with mean depths
ranging from 1.2 to 1.5 feet. The cross-sectional areas for these riffles range from 26.0 to
31.5 square feet. All of the cross-sections were taken within the reach to be restored. All
cross-sections classed as type-F or G channels as the amount of incision increases
downstream. The stream has the following average characteristics:
Bankfull Width: 27 feet
Bankfull Cross-sectional Area: 30 square feet
Bankfull Mean Depth: 1.3 feet
Bankfull Maximum Depth: 4.1 feet
Average Water Surface Slope: 0.002 feet/feet
Entrenchment Ratio: >6.0
Sinuosity: <1.05
Bank Height Ratio 2.0
The entire length of channel within the restoration site was rated using the Bank Erosion
Hazard Index (BEHI). The most likely bank to erode was assessed throughout the reach.
The reach was subdivided into sections with similar erosional characteristics such as
surface protection, root depth, root density, and bank angle. Results are listed in Table 1.
The overall restoration reach has a BEHI rating of high, although two sections had a
BHEI rating of very high and extreme. It is likely these two areas will expand as erosion
continues. The main cause of the very high and extreme ratings are due to the lack of
significant deep rooting vegetation and surface protection. Restoration will reestablish
deep rooting vegetation along the banks throughout the entire reach.
2.2.3 Soils of the Restoration Site
According to the preliminary soil maps for New Hanover County, soils adjacent to the
Middle Branch of Creek within the restoration site are mapped as Rimini, Baymeade and
Lynn Haven soils (Figure 3). Investigation of the soils adjacent to the stream indicates
that all three soils are present, although Lynn Haven is the most common. Lynn Haven is
a fine sandy soil that is well drained. These permeable soils occur on nearly level
floodplains along creeks and rivers. The original wetland soils where most likely covered
and removed when the golf course was built up and the creek was straightened
Soil textures encountered include sand and fine sand. The seasonal high water table was
observed to be greater than 40 inches for most soils within the project. Slopes range from
0 to 6 percent.
2.2.4 Terrestrial Plant Communities
The following sections describe the existing plant communities on and adjacent to the
restoration site. For purposes of this project, three plant communities are described:
Managed Land, Bottomland Forest, and Upland Hardwood Forest. Nomenclature follows
Radford (1968).
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New Hanover County, NC
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New Hanover County, NC
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RESTORATION PLAN
11
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.2.5 Wildlife Observations
Wildlife and signs of wildlife were noted during on-site visits, however, a formal wildlife
survey was not performed. Tracks of white tailed deer (Odocoileus virgin ianus) and
raccoon (Procyon Iotor) were observed along the stream banks. A variety of birds were
observed in the thickets and shrubs surrounding the stream channel and forest, including:
various sparrows.
2.2.5.1 Possible Invasive Wildlife
The following species were identified during site visits to the Middle Branch of Hewlett's
Creek; Asian tiger mosquito (Aedes albopictus), Bullfrog (Rana catesbeiana) (auditory
identification), European gypsy moth (Lymantria dispar), and European starling (Sturnus
vulgaris). The bullfrog is listed based on auditory identification by one of the project
researchers. The gypsy moth is listed based on visual identification of nests. The
mosquito and starling are listed due to their ubiquitous nature.
2.2.6 Endangered Species
The NCSU design team has not identified endangered plant or animal species or any such
habitat that would support the endangered species listed in this section. The NCSU
design team has made multiple visits to the Pine Valley Country Club and the restoration
site. Below is a list obtained from Natural Heritage, of the endangered of concern for
New Hanover County.
2.2.6.1 Endangered Flora
Vascular Plants:
Cooley's meadowrue
Rough-leaved loosestrife
Seabeach amaranth
Bog St. John's-wort
Carolina asphodel
Carolina bishopweed
Carolina beaksedge
Chapman's sedge
Coastal golden rod
"Dune bluecurls"
Pickering's dawnflower
Pondspice
Sandhills milkvetch
Savanna indigo-bush
Spiked medusa
Springy flowering goldenrod
Tough bumelia
Endangered
Endangered
Threatened
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
1?
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Venus flytrap Federal Species of Concern
2.2.6.2 Endangered Fauna
Vertebrates:
Red-cockaded woodpecker Endangered
Shortnose sturgeon Endangered
West Indian Manatee Endangered
American Alligator Threatened
Green sea turtle Threatened
Loggerhead sea turtle Threatened
Piping Plover Threatened
Carolina gopher frog Federal Species of Concern
Eastern painted bunting Federal Species of Concern
Mimic glass lizard Federal Species of Concern
Northern pine snake Federal Species of Concern
Southeastern myotis Federal Species of Concern
Southern Hognose snake Federal Species of Concern
Invertebrates:
Arogos skipper
Buchholz's dart mouth
Cape Fear threetooth
Croatan crayfish
Magnificent rams-horn
Rare skipper
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
13
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
3.0 REFERENCE REACHES
Reference reaches were utilized on which the morphological characteristics were
measured to determine a range of values for the stable dimension, pattern, and profile of
the proposed channel. The following sections include a detail of three of the reference
reaches that were used for design of the restoration plan for the Middle Branch of
Hewlett's Creek. The reference reaches used along with the bankfull area, and current
constraints as the base for the preliminary design.
3.1 JOHANNAH CREEK
The Johannah creek has a drainage area of 1.18 square miles. Angela Moreland of the
NCSU Water Quality group completed the stream survey of Johannah creek in the
summer of 2001. The stream had a bankfull channel width of 10.4 feet and a bankfull
mean depth of 0.8 feet. Johannah Creek is a C5 stream type from Rosgen Classification
system. The morphological characteristics of this reference stream are included in Table
2.
3.2 PANTHER BRANCH
The Panther branch has a drainage area of 1.69 square miles. Angela Moreland of the
NCSU Water Quality group completed the stream survey of Panther branch in the
summer of 2001. The stream had a bankfull channel width of 11.5 feet and a bankfull
mean depth of 1.6 feet. Panther Branch is an E5 stream type from Rosgen Classification
system. The morphological characteristics of this reference stream are included in Table
2.
3.3 BATORORA BRANCH
Angela Moreland of the NCSU Water Quality group completed the stream survey of
Batorora branch in the summer of 2001. The stream had a bankfull channel width of 15.5
feet and a bankfull mean depth of 1.5 feet. Batorora Branch is an E5 stream type from
Rosgen Classification system. The morphological characteristics of this reference stream
are included in Table 2.
15
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Table 2. Middle Branch of Hewlett's Creek Morphology (Existing,
Design, and Reference)
Parameter Existing Reference Reference Reference Design
Reach Name Hewlett Panther Johannah Batorora Hewlett
Bankfull XSEC Area, Abkf (ft) 30 17.9 8.6 23.9 30
Bankfull Width, Wbkf (ft) 20 11.5 10.4 15.5 19
Bankfull Mean Depth, Dbkf (ft) 1.5 1.6 0.8 1.5 1.6
Width to Depth Ratio, W/D (ft/ft) 13.3 7.4 12.6 10.1 12
Entrenchment Ratio, Wfpa/Wbkf (ft/ft) 2 17.4 19.2 12.9 3
Bank Height Ratio, Dtob/Dmax (ft/ft) 2.0 1 1 1 1
Min Bkf Max Depth, Dmax (ft) 1.6 --- --- --- 2.1
Max Bkf Max Depth, Dmax (ft) 1.9 --- -- -- 2.8
Min Bkf Max Depth, Dmax/Dbkf 1.1 1.6 1.3 1.4 1.3
Max Bkf Max Depth, Dmax/Dbkf 1.3 1.8
Min Meander Length, Lm (ft) 100 --- --- --- 86
Max Meander Length, Lm (ft) 280 --- --- --- 171
Min Meander len Ratio, Im/Wbkf 5 2.3 1.9 4.1 4.5
Max Meander Len Ratio, Lm/Wbkf 14 9.1 5.1 6.8 9
Min Radius of Curvature, Rc (ft) 60 --- - -- 34
Max Radius of Curvature, Rc (ft) 80 --- -- - 49
Min Rc Ratio, Rc/Wbkf 3 0.5 0.9 0.7 1.8
Max Rc Ratio, Rc/Wbkf 4 1.5 2.3 2.6 2.6
Min Belt Width, Wblt (ft) 25 --- --- --- 42
Max Belt Width, Wblt (ft) 40 --- --- --- 76
Min MW Ratio, Wblt/Wbkf (ft) 1.3 1.9 1.3 2.9 2.2
Max MW Ratio, Wblt/Wbkf (ft) 2 8.7 4.4 4.5 4
Sinuosity, K 1.05 1.2 1.2 1.2 1.2
Valley Slope, Sval (ft/ft) .0026 .0040 .0026 .0061 .0026
Channel Slope, Schan=Sval/K (ft/ft) .0025 .0033 .0021 .0051 .0021
Pool Slope, Spool (ft/ft) 0 --- --- --- 0
Pool Slope Ratio, Spool/Schan 0 0 0 0
Min Pool Depth, Dpool (ft) 1.7 --- - - --- 2.4
Max Pool Depth, Dpool (ft) 2 --- - - 3.0
Min Pool Depth Ratio, Dpool/Dbkf 1.1 1.6 1.9 2 1.5
Max Pool Depth Ratio, Dpool/Dbkf 1.3 2
Min Pool Width, Wpool (ft) 21 --- - --- 19
Max Pool Width, W pool (ft) 25 --- --- --- 22.8
Min Pool Wid Ratio, Wpool/Wbkf 1.1 1 1.2 0.9 1
Max Pool Wid Ratio, W pool/W bkf 1.3 1.2
Min Length Pool Spacing, Lps (ft) 40 --- --- --- 57
Max Length Pool Spacing, Lps (ft) 220 --- --- --- 114
Min Pool Spacing Ratio, Lps/Wbkf 2 1.3 1.2 1.7 3
Max Pool Spacing Ratio, Lps/Wbkf 11 5.7 3.8 3.9 6
16
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.0 STREAM CHANNEL DESIGN
This restoration will classify as a Priority 2 restoration (Rosgen, 1997). The floodplain
will be re-established to fit the existing or slightly raised stream profile. The grade of the
stream will be raised in some areas and a floodplain will be established at the new
bankfull elevation. Table 3 describes and summarizes the four priorities of incised river
restoration (Rosgen, 1997). The proposed stream restoration will restore the natural
meander pattern, modify channel cross-section restore bedform, improve sediment
transport capacity, enhance habitat, and re-establish a floodplain for the stream.
The design was based upon Dave Rosgen's natural channel design methodology. As
described in Section 3.0, reference reaches were utilized on which the morphological
characteristics were measured to determine a range of values for the stable dimension,
pattern, and profile of the proposed channel. The measured and proposed morphological
characteristics are shown in Table 2.
A conceptual design was developed from the range of values listed in Table 2. This
stream restoration project will result in approximately 3,600 restored linear feet (as
measure from the thalweg) of The Middle Branch of Hewlett's Creek. The plan view of
the proposed restoration design can be seen in Figures 4, 5 and 6.
17
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Table 3. Priorities, Description and Summary for Incised River Restoration
DESCRIPTION METHODS ADVANTAGES DISADVANTAGES
PRIORITY I Re-establish channel on Re-establishment of 1) floodplain re-
Convert G and/or F previous floodplain using relic floodplain and stable establishment could cause
stream types to C and/or channel or construction of channel: flood damage to urban
E at previous elevation new bankfull discharge 1) reduces bank height and agricultural and industrial
w/floodplain channel. Design new channel streambank erosion development.
for dimension, pattern and 2) reduces land loss 2) downstream end of
profile characteristic of stable 3) raises water table project could require grade
form. Fill in existing incised 4) decreases sediment control from new to
channel or with discontinuous 5) improves aquatic and previous channel to prevent
oxbow lakes level with new terrestrial habitats head-cutting.
floodplain elevation. 6) improves land
productivity, and
7) improves aesthetics.
PRIORITY 2 If belt width provides for the 1) decreases bank height 1) does not raise water
Convert G and/or F minimum meander width ratio and streambank erosion table back to previous
stream types to C or E. for C or E stream types, 2) allows for riparian elevation
Re-establishment of construct channel in bed of vegetation to help stabilize 2) shear stress and velocity
floodplain at existing or existing channel, convert banks higher during flood due to
higher, but not at existing bed to new 3) establishes floodplain to narrower floodplain
original level floodplain. If belt width is too help take stress of channel 3) upper banks need to be
narrow, excavate streambank during flood sloped and stabilized to
walls. End-hall material or 4) improves aquatic habitat reduce erosion during
place in streambed to raise 5) prevents wide-scale flood.
bed elevation and create new flooding of original land
floodplain in the deposition. surface
6) reduces sediment
7) downstream grade
transition for grade control
is easier.
PRIORITY 3 Excavation of channel to 1) reduces the amount of 1) high cost of materials
Convert to a new stream change stream type involves land needed to return the for bed and streambank
type without an active establishing proper river to a stable form. stabilization
floodplain, but dimension, pattern and 2) developments next to 2) does not create the
containing a floodprone profile. To convert G to B river need not be re-located diversity of aquatic habitat
area. Convert G to B stream involves an increase in due to flooding potential 3) does not raise water
stream type, or F to Be width/depth and entrenchment 3) decreases flood stage for table to previous levels.
ratio, shaping upper slopes the same magnitude flood
and stabilizing both bed and 4) improves aquatic
banks. A conversion from F habitat.
to Be stream type involves a
decrease in width/depth ratio
and an increase in
entrenchment ratio.
PRIORITY 4 A long list of stabilization 1) excavation volumes 1) high cost for
Stabilize channel in materials and methods have reduced stabilization
place been used to decrease stream 2) land needed for 2) high risk due to
bed and bank erosion, restoration is minimal excessive shear stress and
including concrete, gabions, velocity
boulders and bio-engineering 3) limited aquatic habitat
methods depending on nature of
stabilization methods used.
Source: Rosgen, 1997, "A Geomorphological Approach to Restoration of Incised Rivers"
18

CITY OF WILMINGTON STORMWATER POND
STAGING AND STOCKPILE AREA
2.75 acres
1.) Area shall be graded smooth upon completion of earthwork activities, with a
slope toward the storm water pond and a maximum side slope of 3:1
2.) Area shall be stabilized with temporary seed upon completion of earthwork
3.) Area shall be sprigged with Bermuda grass variety between May 15th and
June 15th, the contractor shall coordinate with the golf course superintendent
LEGEND
CROSS VANE CART PATH

'See D00 13 (C-8) -Se" Delal 15 (C-8)
LOG VANE ' CULVERT CROSSING

'See Detat 11 (C-8) -See Detail 7 (C-7)
ROOT WADS * RETAINING WALL
-See Det,il 17 (C-8) 'See Detol 16 (C-9)
NOTE: Structure placement on Plan Sheets
are for location only. Actuel placement shall
be directed by Resident Engineer
DETAIL
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M SEMER.INE
CU RVE TABLE
CURVE LENGTH RADIUS
C- 1 69.6 39.5
C- 2 22.3 320
C- 3 49.8 34.0
C- 4 25.0 34.0
C- 5 43.3 39.0
C- 6 72.1 42.0
6&1 3&0
69.2 42.0
3&9 36.0
K 29.0 40.0
5&7 43.0
43.7 35.0
38.6 33.0
CI- 36.1 34.0
NOTE: The listed Radius of Curvatures are
measured from the stream centerline.
Actual Radius of Curvatures maybe
adjusted by Resident NCSU Engineer
CLAY PLUG
SEE DETUL 9 (C-7)
LINE TABLE
LINE LENGTH BEARING NORTHING EASTING
L- 1 25.5 N2711'58E 161485 2332881
L- 2 31.9 N87'40633'W 181515 2332892
L- J 31.9 N1 358'53'W 161554 2332951
L- 4 53.9 N3819'54E 161607 2332952
L- 5 3&5 N44V1'11'W 181691 2332983
L- 6 19.4 N73-26'1 5E 161780 2332973
L- 7 37.5 N21W'WW 161&12 2333028
L- 8 41.9 N7821'23'W 161914 2333054
L- 9 29.8 N2127'35'E 161927 2333125
L- 10 424 N70'06'16-E 151972 2333159
L- 11 35.9 N1150'16'W 162068 2333275
L- 12 30.3 N752744E 162150 2333293
L- 13 24.4 N12W'09'W 162192 23,33344
L- 14 31.7 N70.48'47E 162248 , 2333357
NOTE: The listed Northing and Easting Columns
represent the head of the appropriate riffle section
along the centerline of the stream. Actual riffle
starting locations, bearing and lengths maybe adjusted
by Resident NCSU Engineer

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LEGEND
CROSS VANE * CART PATH
*
-
•See Deta9 13 (C-B)
•See Deto9 15 (C-8)
LOG VANE * CULVERT CROSSING

•See Detail 11 (C-8) -See Detail 7 (C-7)
ROOT WADS * RETAINING WALL

-See Det.1 12 (C-8)- 'See Detal 16 (C-9)
DETAIL
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PROJECT NO.
FILENAME
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CURVE LENGTH RADIUS
C- 29 24.6 39.0
C- 30 15.5 40.0
C- 31 2119 32.0
C- 32 2&1 41.0
C- 33 41.4 31.0
C- 34 48.9 35.0
C- 35 53.8 320
C- 36 5&8 320
C- 37 46.0 40.0
C- 38 19.0 420
C- 39 30.8 35.0
C- 40 34.4 34.0
C- 41 59.4 3&0
C- 42 30.1 420
LINE TABLE
LINE LENGTH BEARING NORTHING EASTING
L- 30 31.4 N2919'41'W 162775 2334239
L- 31 30.5 N24'44'00'W 152656 2334376
L- 32 29.5 N88'36'28'E 162514 2334412
L- 33 27.4 N3900'55'W 162603 2334467
L- 34 28.4 N55.31'13'E 162575 2334572,
L- 35 Z5.4 N27727'36'W 162580 2334589
L- 36 24.9 N3804'01'E 162553 2334648
L- 37 2&1 N1604'16'W 162563 2334713
L- 38 2113 N82'49'10'E 162513 2334758
L- 39 35.3 N6719'24W 152512 2334805
L- 40 493 N60.48'42E 162503 2334867
L- 41 30.0 N51040240W 162527 233494,3
L- 42 34.4 N223S44-E 162521 2335018
L- 43 36.1 N7005'1YE 162572 2335054
NOTE: The listed Radius of Curvatures are
measured from the stream centerline.
Actual Radius of Curvatures maybe
adjusted by Resident NCSU Engineer
NOTE: The listed Northing and Easting Columns
represent the head of the appropriate riffle section
along the centerline of the stream. Actual riffle
starting locations, bearing and lengths maybe adjusted
by Resident NCSU Engineer
+ (C-B) - /i
REPLACEMENT CART PATH
SEE DETAIL 15 (C-5)
DETAIL
PRM070 UR AR?Na
v^? -T

LEGEND
CROSS VANE " CART PATH

•See Detail 13 (C-8) 'See De1a115 (C-8)
LOG VANE * CULVERT CROSSING

-See Detail 11 (C-8) •See DetoB 7 (C-7)
ROOT WADS * RETAINING WALL
r e
•See Detoll 12 (C-8) •See Det.l 16 (C-9)
NOTE: Structure placement on Plan Sheets
are for location only. Actual placement shall
be directed by Resident Engineer
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C- 15 37.3 420
C- 16 35.0 40.0
C- 17 57.8 34.0
C- 16 58.1 30.0
C- 19 67.7 30.0
C- 20 66.4 30.0
C- 21 27.2 35.0
C- 22 17.0 36.0
C- 23 30.0 35.0
C- 24 326 36.0
C- 25 34.2 35.0
C- 25 44.9 37.0
C- 27 34.5 33.0
C- 28 59.4 39.0
NOTE: The listed Radius of Curvatures are
measured from the stream centerline.
Actual Radius of Curvatures maybe
adjusted by Resident NCSU Engineer
q STREAM (SREV)
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REPLACEMENT CART PATH
SEE DETAIL 15 (C-B)
LINE TABLE
LINE LENGTH BEARING NORTHING EASTING
L- 15 27.1 ND915'44'w 162287 2311402
L- 18 57.8 N56 4'3T 162347 2333411
L- 17 33.5 N0958'50'W 182411 2333472
L- 18 34.4 N85'05'15'W 162482 2333500
L- 19 33.1 N31-35'14'W 162520 2333562
L- 20 21.7 N61'4 '46'W 162587 2333563
L- 21 26.6 N 28-58'25"W 162613 2333841
L- 22 25.2 N33'3'38 162683 2333830
L- 23 16.5 N7918'03' 162768 2333852
L- 24 2&2 N59 6'00'W 162788 2333884
L- 25 28.8 N501)9'17' 162777 2733938
L- 26 26.1 N54'0448'W 162798 2333991
L- 27 30.1 N49-4505- 162783 2334045
L- 28 29.0 N43'51'58-W 162600 2334110
L- 29 29.8 N5716'0 ' 162778 233416)
NOTE: The listed Northing and Easling Columns
represent the head of the appropriate riffle section
along the centerline of the stream. Actual riffle
starting locations, bearing and lengths maybe adjusted
by Resident NCSU Engineer
DETAIL
PRGPGSEM,UM" 1-No
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LEGEND
CROSS VANE * CART PATH
*
-
•See Detmt 13 (C-6) •See Derail IS (C-6)
LOG VANE * CULVERT CROSSING

-See Detail 11 (C-8) •See Detail 7 (C-7)
ROOT WADS * RETAINING WALL
T?
•See Dela9 12 (C-8) •See Detail 16 (C-9)
NOTE: Structure placement on Plen Sheets
are for location only. Actual placement shall
be directed by Resident Engineer
SCALE 1" = 40'
40 0 40 80
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PRD.ECT NO.
FILENAME
TT.
S-ET NO.
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Existing pattern measurements were taken from the topographic mapping. A stable
pattern will be established by establishing new meanders along the channel. This will be
achieved by introducing meanders into the stream with radius of curvatures and lengths
based on reference reach data and the existing constraints. The maximum stream length
and sinuosity has been designed into the new channel based on the reference data and
project constraints. Introduction of these meanders will improve habitat while lowering
slope and shear stress.
4.1.3 Bedform
The existing bedform along the Middle Branch of Hewlett's Creek is in poor condition.
Long, straight sections of the channel consist of predominantly run bedform features. The
design channel will incorporate ripples and pools to provide bedform common to E5
stream types. Pools will be located in the outside of meander bends with riffles in the
inflection points between meanders. The ripples will have a thalweg depth of 1.6 feet
while the pools will be deeper with a maximum depth of 3.0 feet. A graph of the
proposed profile can be seen in Figure 8. The profile may be adjusted slightly during the
final design phase of the project.
Cross-vanes will be utilized as grade control structures and to tie the relocated sections
back into the existing channel. The cross vanes will be constructed out of natural
materials such as wood and some boulders.
The existing pool-to-pool spacing is impaired in areas due to tight meander geometry.
The proposed spacing is 57 to 114 feet, which is within the range of 3 and 6 bankfull
widths as determined from the reference reach data. To accomplish this, pools will be
realigned or constructed such that they will be located in the outside of the meander
bends. Bedform will also be addressed through the strategic placement of natural material
structures such as cross vanes, root wads and large woody debris. Modifications to the
bedform will provide stability and habitat to the channel.
4.1.4 Riparian Areas
A riparian zone will be created around the new proposed stream channel to enhance both
aquatic and terrestrial habitat as well as stabilize the stream channel. The riparian zone
will extend at least 15 feet on either side of the channel from the top of bank. Were ever
possible the riparian zone will extend at least 25 feet on either side of the channel. These
areas will be planted with appropriate riparian vegetation as described in Section 6.0
Habitat Restoration. The riparian zone is limited by the urban constraints and the
constraints of an active golf course that includes play that cross the stream channel.
23
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Figure 7: Typical Cross-Sections
Typical X-Section Riffle
34.00
32.00
30.00 0
28.00
a?
26.00 w
24.00
-60.00 -40.00 -20.00 0.00 20.00 40.00 60.00
Off Set from CL (ft)
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-80 -60 -40 -20
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Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.2 SEDIMENT TRANSPORT
A stable stream has the capacity to move its sediment load without aggrading or
degrading. The total load of sediment can be divided into bed load and wash load. Wash
load is normally composed of fine sands, silts and clay and transported in suspension at a
rate that is determined by availability and not hydraulically controlled. Bed load is
transported by rolling, sliding, or hopping (saltating) along the bed. At higher discharges,
some portion of the bed load can be suspended, especially if there is a sand component in
the bed load. Bed material transport rates are essentially controlled by the size and nature
of the bed material and hydraulic conditions (Hey 1997).
Critical dimensionless shear stress can be found using Shield's Curve and surface particle
sample from a representative riffle in the reach. A riffle bed surface pebble count was
taken at a riffle on the Middle Branch of Hewlett's Creek. The riffle bed surface d50 was
then calculated to be 0.06 mm. The shear stress placed on the sediment particles is the
force that entrains and moves the particles, in a given channel geometry. From Shields
curve the shear stress that entrains and moves particles in this stream based on the d50 is
.0025 lbs/sqft.
Wetted perimeter was measured off of a CADD file of the typical riffle cross-section
drawn to scale. The wetted perimeter was measured to be 29 ft, while the cross-sectional
area was 30 sqft this produced a hydraulic radius of 1.03. The Slope for the used for the
shear stress calculation is 0.0023. The resultant shear stress for the proposed channel is
0.15 lbs/sgft, this shear stress is sufficient to move the d84 of the riffle bed material,
which is 0.15 mm. Shield's Curve predicts that this stream can move a particle that is, on
average, greater than 5 mm. Since the D84 was 0.15 mm and Shield's Curve predicts 5
mm, the proposed stream has the competency to move its bed load.
Sediment transport analysis was examined at the restoration site through the comparison
of existing and post restoration shear stress analysis. The existing channel does not
appear to be aggrading so it is implied that it is more capable of transporting its
watershed sediment load. Two existing shear stresses are examined and one restored
shear stress. Shear stress is approximated using the equation shear stress = density of
water times the hydraulic radius times the average water surface slope. Existing bankfull
shear stress is 0.233 lbs/sgft. The top of bank shear stress is 0.454 lbs/sgft.
Post restoration, average water surface slope will be decreased and the floodplain will be
established adjacent to the bankfull channel thus lowering the top of bank shear stress
significantly. The post restoration bankfull shear and top of bank shear stress is 0.222
lbs/sgft. These calculations were confirmed with HEC-RAS modeling.
4.3 FLOODING ANALYSIS
This restoration site is not in a mapped FEMA regulatory floodway zone and therefore, is
not subject to FEMA regulations. NCSU design team has also received verification from
26

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
the City of Wilmington Division of Stormwater that this reach of Hewlett's Creek is not
FEMA mapped and does not have a recorded history of flood related incidents. Currently
there are no structures located in the adjacent areas that would be impacted by floodplain
alterations. The Priority 2 restoration of the stream will leave the stream's existing profile
elevations essentially the same. A new floodplain will be established so that the active
stream will be able to access it during larger storm events. Considering the type of
restoration it is assumed that for smaller events the water surface elevations along the
stream shall remain the same. During storms where the stream accesses the newly
establishment floodplain the new water surface elevations are expected to be lower than
the existing water surface elevations of storms of the same magnitude. The restoration
will create neither positive nor negative water surface elevation changes during the larger
storm events (greater than 25-year). HEC-RAS was used to analyze both existing and
proposed conditions after the design was finalized. Sheer stress and flood stages were
compared at various return intervals to evaluate the design.
4.4 STRUCTURES
Several different structures made of natural materials will be installed along the Middle
Branch of Hewlett's Creek. These structures include cross vanes, single vanes, and root
wads. Natural materials such rocks and root wads will be used to create these structures
from off-site sources and on-site sources.
4.4.1 Cross Vane
A cross vane structure serves to maintain the grade of the stream. The design shape is
roughly that of the letter "U" with the apex located on the upstream side at the foot of the
riffle. Footer rocks are placed in the channel bottom for stability. Rocks or logs are then
placed on these footer rocks in the middle of the channel at approximately the same
elevation as the ripple. On either side of the channel, rocks or logs are placed at an angle
to the stream bank, gradually inclining in elevation until they are located above the
bankfull surface directly adjacent to the stream bank. Water flowing downstream is
directed over the vane towards the middle of the channel. Rocks or a log placed at the
apex determine the bed elevation upstream. A cross vane is primarily used for grade
control and to protect the stream banks.
4.4.2 Root Wads
The objectives of these structure placements are as follows: (1) protect the stream bank
from erosion; (2) provide in-stream and overhead cover for fish; (3) provide shade,
detritus, terrestrial insect habitat: (4) look natural, and (S) provide diversity of habitats
(Rosgen 1996). A footer log and boulder are placed on the channel bottom abutting the
stream bank along an outside meander that will provide support for the root wad and
additional stability to the bank. A large tree root wad is then placed on the stream bank
with additional boulders and rocks on either side for stability. Flowing water is deflected
away from the bank and towards the center of the channel.
27

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.4.3 Single Vane
A single vane structure serves to maintain the pattern of the stream. Footer rocks are
placed in the channel bottom for stability. Rocks or logs are then placed on these footer
rocks in the middle of the channel at approximately the same elevation as the ripple. On
either side of the channel, rocks or log is placed at an angle to the stream bank, gradually
inclining in elevation until they are located above the bankfull surface directly adjacent to
the stream bank. Water flowing downstream is directed over the vane towards the middle
of the channel. A single vane is primarily used to turn the stream flow and control and to
protect the stream banks.
Specific location of these structures will be determined during final design.
28

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
5.0 HABITAT RESTORATION
The restoration plan requires the establishment of riparian vegetation at the site. The
proposed vegetation is described in the following sections.
5.1 VEGETATION
Vegetation that develops a quick canopy, has an extensive root system, and a substantial
above-ground plant structure is needed to help stabilize the banks of a restored stream
channel in order to reduce scour and runoff erosion. In natural riparian environments,
pioneer plants that often provide these functions are alder, river birch, silky dogwood,
and willow. Once established, these trees and shrubs create an environment that allows
for the succession of the other riparian species including ashes, black walnuts, red
maples, sycamores, oaks, and other riparian species.
In the newly restored stream channel, revegetation will be vital to help stabilize the
stream banks and establish a riparian zone around the restored channel. Revegetation
efforts on this project will emulate natural vegetation communities found along relatively
undisturbed stream corridors. To quickly establish dense root mass along the channel
bank, a native grass mixture will be planted on the streambed and bank. Shrubs will be
utilized on the stream bank and along the floodplain to provide additional root mass.
Extra care will be given to the outside of the meander bends to ensure a dense root mass
in those areas of high stress. Coir matting or similar material will be used to provide
erosion protection until vegetation can be established. Along the tops of the channel
banks, trees, shrubs and a native grass mixture will be planted.
A mixture of seeds, live stakes, bare root, as well as balled in burlap nursery stock, some
2 "- 4" caliper tree and transplants will be used to stabilize the banks. Proposed species
to be planted included, but are not limited to:
Trees
Blackcherry (Prunus serotina)
Blackgum (Nyssa sylvatica)
Loblolly Bay (Gordonia lasianthus)
River Birch (Betula nigra)
Sugarberry (Celtis laevigata)
Shrubs
American hornbeam (Carpinus caroliniana)
Fetter bush (Lyonia lucida)
Inkberry (Ilex glabra)
Marsh mallow (Hibiscus nioscheutos)
Silky dogwood (Conzus amomum)
Sweet pepperbush (Clethra alnifolia)
Virginia willow (Itea virginica)
29

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Herbs- Permanent seed mixture
Deertongue (Panicum clandestinum)
Purple love grass (Ergrostis spectabilis)
Switch Grass (Panicum virgatitm)
Tussock sedge (Carex stricta)
Other herbaceous vegetation
Dwarf spike-rush (Eleocharis parvula)
Ironweed (Ventonia noveboracensis)
Jack-in-the-pulpit (Arisaema triphyllunt)
Woody vegetation will be planted between February and May to allow plants to stabilize
during the dormant period and set root during the spring season. In the areas where
invasive and exotic species are located, during construction and monitoring control by
removal or appropriate herbicides will be implemented to prevent competition with the
revegetation efforts.
5.2 RIPARIAN BUFFERS
At least three different types of riparian buffers will be employed to vegetate the restored
channel. All buffers will use plants native to the coastal plain region of North Carolina.
In areas where the fairways cross the stream channel, vegetation will be kept to a minimal
height so as not to obstruct views and play within the crossing. The areas along the city
sewer line (within approximately 10' to either side of the utility) will be planted with
vegetation having shallow (limited) root structure so that the sewer line and access to it
shall not be impacted or impeded. The remaining areas will be planted with native trees,
shrubs, grasses and other herbaceous vegetation in order to restore natural coastal plain
plant communities. Proposed species to be planted include but are not limited to those
listed in the above section
5.2.1 Temporary Seeding
A temporary seed mixture will be applied to all disturbed areas immediately after
construction activities have completed. This temporary seed mixture will provide erosion
control until permanent seed can become established. Permanent seed will be native to
the coastal region of North Carolina.
30

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
6.0 MONITORING
6.1 STREAM CHANNEL
Monitoring of the stability of the channel is recommended to occur approximately 6
months after restoration is complete or after bankfull (or greater) events and should
continue annually for a period of 3 to 5 years. Monitoring practices may include, but are
not limited to, installing bank erosion pins and a toe pin, monumented cross-sections,
scour chains, macroinvertebrate studies, longitudinal profiles, conducting the bank
erosion hazard rating guide and establishing photo reference points. The purpose of
monitoring is to determine bank stability, bed stability, morphological stability and
overall channel stability. Table 4, below, can be used for selecting practices.
Table 3. Stream Monitoring Practices
PRACTICE STABILITY ASSESSMENT
Bank Erosion Pins with Toe Pin -Lateral or bank stability
Monumented Cross-Section -Vertical or bank stability
-Lateral or bank stability
Scour Chains -Vertical or bed stability
-Scour depth fora articular storm
Scour Chain w/ Monumented
Cross-Section -Vertical or bed stability
-Sediment transport relations
-Biological interpretations
Longitudinal Profile -Channel profile stability
Bank Erosion Hazard Guide -Bank erosion potential
Photo Reference Points -Overall channel stability
Macroinvertebrate -Biological indication of water quality
6.2 VEGETATION
Prior to planting, the site will be inspected and checked for proper elevation and
suitability of soils. Availability of acceptable, good quality plant species will be
determined. The site will be inspected at completion of planting to determine proper
planting methods, including proper plant spacing, density, and species composition.
Competition control will be implemented if determined to be necessary during the early
stages of growth and development of the tree species. Quantitative sampling of the
vegetation will be performed between August 1 and November 30 at the end of the first
year and after each growing season until the vegetation criteria is met.
In preparation for the quantitative sampling, 50 by 50 feet (0.05-acre) vegetative plots
will be established in the reforested area. Plots will be evenly distributed throughout the
31
,. N
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
site. For each plot, species composition and density will be reported. Photo points will be
taken within each zone. Monitoring will take place once each year for five years.
Success will be determined by survival of target species within the sample plots. At least
six different representative tree species should be present on the entire site. If the
vegetative success criteria are not met, the cause of failure will be determined and
appropriate corrective action will be taken.
6.3 MACROIN VERTEBRATES
A monitoring period of 3 to S years is commonly suggested to determine changes in
macroinvertebrate populations within a newly restored stream. The North Carolina
Wetlands Restoration Program will determine a macroinvertebrate monitoring policy.
32

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
7.0 REFERENCES
Amoroso, J.L., ed. 1999. Natural Heritage Program List of the Rare Plant Species of
North Carolina. North Carolina Natural Heritage Program, Division of Parks and
Recreation, North Carolina Department of Environment and Natural Resources. Raleigh,
North Carolina.
Cowardin, L.M., V. Carter, F.C. Golet and E.T. LaRoe. 1979. Classification of Wetlands and
Deepwater Habitats of the United States. U.S. Fish and Wildlife Service, Office of
Biological Services, FWS/OBS-79/3 I. U.S. Department of the Interior, Washington, DC.
Choate, J.R., J.K. Jones, Jr., and C. Jones. 1994. Handbook of Mammals of the South-Central
States. Louisiana State University Press, Baton Rouge, Louisiana.
Doll, B. A., et al. 2000. Hydraulic Geometry Relationships for Urban Streams throughout the
Piedmont of North Carolina. American Water Resources Association.
Godfrey, R.K., and J.W. Wooten. 1979. Aquatic and Wetland Plants of Southeastern United States.
Monocotyledons. The University of Georgia Press, Athens, Georgia.
Godfrey, R.K., and J.W. Wooten. 1981. Aquatic and Wetland Plants of Southeastern United States.
Dicotyledons. The University of Georgia Press, Athens, Georgia.
Harrelson, Cheryl, C.L. Rawlins and John Potyondy. 1994. Stream Channel Reference Sites: An
Illustrated Guide to Field Technique. United States Department of Agriculture, Forest Service.
General Technical Report RM-245.
Hey, Richard and Dave Rosgen. 1997. Fluvial Geomorphology for Engineers. Wildland Hydrology,
Pagosa Springs, Colorado.
LeGrand, H.E., Jr. and S.P. Hall, eds. 1999. Natural Heritage Program List of the Rare
Animal Species of North Carolina. North Carolina Natural Heritage Program, Division of
Parks and Recreation, North Carolina Department of Environment and Natural
Resources. Raleigh, North Carolina.
NCDENR. "Water Quality Stream Classifications for Streams in North Carolina." Water Quality
Section. http:/Ih2o.ear.state.nc.us/wghome.htmi (16 July 2001).
Radford, A.E., H.E. Ahles and G.R. Bell. 1968. Manual of the Vascular Flora of the Carolinas. The
University of North Carolina Press, Chapel Hill, North Carolina.
Rosgen, Dave. 1997. A Geomorphological Approach to Restoration of Incised Rivers.
Wildland Hydrology. Proceedings of the Conference on Management of Landscapes
Disturbed by Channel Incision.
33

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Schafale, M. P. and A. S. Weakley. 1990. Classification of the Natural Communities of
North Carolina: Third Approximation. North Carolina Natural Heritage Program.
Raleigh, North Carolina
United States Department of Agriculture - Soil Conservation Service. December, 1977. "Soil
Survey of Guilford County, North Carolina." US Government Printing Office, Washington,
DC.
United States Fish and Wildlife Service. "Region 4, Southeast Region/Endangered Species." North
Carolina Ecological Services. http://nc-es.fws.gov/ (August 2001).
USDA, NRCS. 2001. The PLANTS Database, Version 3.1 (http://plants.usda.gov). National Plant
Data Center, Baton Rouge, LA 70874-4490 USA.
34

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.2.5 Wildlife Observations
Wildlife and signs of wildlife were noted during on-site visits, however, a formal wildlife
survey was not performed. Tracks of white tailed deer (Odocoileus virgin ialiits) and
raccoon (Procyon Iotor) were observed along the stream banks. A variety of birds were
observed in the thickets and shrubs surrounding the stream channel and forest, including:
various sparrows.
2.2.5.1 Possible Invasive Wildlife
The following species were identified during site visits to the Middle Branch of Hewlett's
Creek; Asian tiger mosquito (Aedes albopictus), Bullfrog (Rana catesbeiana) (auditory
identification), European gypsy moth (Lyniantria dispar), and European starling (Stunnfs
vulgaris). The bullfrog is listed based on auditory identification by one of the project
researchers. The gypsy moth is listed based on visual identification of nests. The
mosquito and starling are listed due to their ubiquitous nature.
2.2.6 Endangered Species
The NCSU design team has not identified endangered plant or animal species or any such
habitat that would support the endangered species listed in this section. The NCSU
design team has made multiple visits to the Pine Valley Country Club and the restoration
site. Below is a list obtained from Natural Heritage, of the endangered of concern for
New Hanover County.
2.2.6.1 Endangered Flora
Vascular Plants:
Cooley's meadowrue
Rough-leaved loosestrife
Seabeach amaranth
Bog St. John's-wort
Carolina asphodel
Carolina bishopweed
Carolina beaksedge
Chapman's sedge
Coastal golden rod
"Dune bluecurls"
Pickering's dawnflower
Pondspice
Sandhills milkvetch
Savanna indigo-bush
Spiked medusa
Spring-flowering goldenrod
Tough bumelia
Endangered
Endangered
Threatened
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
12

RECEIVED
.,FP 3 2004
0
NC ECOSYSTEM
ENHANCEMENT PROGRAM
Stream Restoration Plan
Hewlett's Creek
New Hanover County, North Carolina
j? 0 S n7
!?1 iaMe1 eni
OIRO .k VA
39
August 31, 2004
Biological
Agricultural
Engineering

- I
1
ANC STATE`QN`LI SITY
Biological & Agricultural Engineering
Weaver Labs, Campus Box 7625
North Carolina State University
Raleigh, North Carolina 27695
WETI.A.NOS / 401 GROUP
SEP 0 `r 2004
WATER QUALITY SECTION
t ?
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
TABLE OF CONTENTS
1.0 INTRODUCTION ............................................................1
1.1 PROJECT DESCRIPTION ..........................................2
1.2 GOALS AND OBJECTIVES ........................................2
1.3 STREAM SURVEY METHODOLOGY ...........................2
1.3.1 Stream Delineation - Classification .........................4
1.3.2 Bankfull Verification ..........................................4
2.0 EXISTING CONDITIONS ...................................................6
2.1 WATERSHED ....................................................... ..6
2. 1.1 General Description of the Watershed .................... ..6
2.1.2 Surface Waters Classification ............................. ...6
2.1.3 Soils of the Watershed ...................................... ...6
2.1.4 Land Use of the Watershed ...................................8
2.2 RESTORATION SITE ................................................8
2.2.1 Site Description .............................................. ..8
2.2.2 Existing Stream Characteristics ............................ ..8
2.2.3 Soils of the Restoration Site ... . ............................ ..9
2.2.4 Terrestrial Plant Communities .............................. ..9
2.2.4.1 Managed Land ..................................... .12
2.2.4.2 Bottomland Forrest ............................... 12
2.2.4.3 Upland Hardwood Forest ........................ 12
2.2.4.4 Possible Invasive Flora ........................... 12
2.2.5 Wildlife Observations.... ................................. 13
2.2.5.1 Possible Invasive Wildlife .......................... 13
2.2.6 Endangered Species ........................................... 13
2.2.6.1 Endangered Flora .................................. 13
2.2.6.1 Endangered Fauna ................................. 14
3.0 REFERENCE REACHES ...................................................15
3.1 JOHANNAH CREEK ...............................................15
3.2 PANTHER BRANCH ...............................................15
3.3 BATORORA BRANCH ............................................15
4.0 STREAM CHANNEL DESIGN ...........................................17
4.1 RESTORATION TECHNIQUES .................................22
4. 1.1 Dimension ......................................................22
4.1.2 Pattern ..........................................................22
4.1.3 Bedform ........................................................23

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.1.4 Riparian Areas ................................................23
4.2 SEDIMENT TRANSPORT . ........................................26
4.3 FLOODING ANALYSIS ... ........................................26
4.4 STRUCTURES ............... ........................................27
4.4.1 Cross Vane ............. ........................................27
4.4.2 Root Wads ............. ........................................27
4.4.3 Single Vanes ...................................................28
5.0 HABITAT RESTORATION ...............................................29
5.1 VEGETATION .......................................................29
5.2 RIPARIAN BUFFERS ..............................................30
5.2.1 Temporary Seeding ..........................................30
3
6.0 MONITORING ...............................................................
6.1 STREAM CHANNEL ...............................................31
6.2 VEGETATION .......................................................31
6.3 MACROINVERTEBRATES .......................................32
7.0 REFERENCES ...............................................................33
LIST OF TABLES
Table 1. Bank Erosion Potential ...............................................10
Table 2. Middle Branch of Hewlett's Creek Morphology .................16
Table 3. Priorities, Desc. & Summary for Incised River Restoration... 18
Table 4. Stream Monitoring Practices .......................................31
LIST OF FIGURES
Figure 2 Watershed Arial ........................................................7
Figure 3 Soils Map.............................................................. 11
Figure 4 Hewlett's Creek Restoration Plan ..................................19
Figure 5 Hewlett's Creek Restoration Plan .................................20
Figure 6 Hewlett's Creek Restoration Plan ..................................21
Figure 7 Typical Cross-Sections ..............................................24
Figure 8 Proposed Longitudinal Profile ......................................25
Figure 1 Site Location ............................................................

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
1.0 INTRODUCTION
The North Carolina Wetlands Restoration Program (NCWRP) has identified The Middle
Branch of Hewlett's Creek as a potential stream restoration site. Hewlett's Creek drains
into the Greenville Sound, the Middle Branch of Hewlett's creek (NCDWQ Stream Index
Number 18-87-26 SA HQW) is located on urban land in the southeast corner of
Wilmington in New Hanover County, North Carolina (Figure 1).
Arcadis first identified Hewlett's Creek as a potential restoration site in a feasibility
report to NCWRP. NCSU is completing the design and will conduct construction
oversight of the restoration of the middle branch of Hewlett's Creek. The portion of
Hewlett's creek that is being evaluated for restoration is within the property boundaries
of the Pine Valley Country Club. The Country Club Membership met on March 17th of
2003 and voted to allow WRP to fund a restoration project focused on the Middle Branch
of Hewlett's Creek.
The Middle Branch of Hewlett's Creek has areas of significant active bank erosion
throughout the proposed project limits. There is evidence of historic straightening and
degradation resulting from this straightening. Thinning and removal of riparian
vegetation has also accelerated the degradation process. The incised condition of the
existing channel is accelerating the erosion process by forcing the channel to contain
larger then bankfull storm events.
The restoration site is located entirely within the property boundaries of the Pine Valley
Country Club. A City of Wilmington 16" RCP sewer line is located along the entire
length of the reach that is being considered for restoration. The sewer line crosses the
existing channel twice within the reach and is offset from the existing channel by a range
of loft to 40ft. There are two power-lines and numerous irrigation lines for the golf
course within the project limits. The Middle Branch of Hewlett's Creek has many urban
constraints, but should be an excellent potential restoration site, and . ideal for
demonstration and education.
Restoration requires determining how far the stream has departed from its natural
stability and then, establishing the stable form of the stream under the current hydrologic
conditions within the drainage area. The proposed restoration will construct a stable
meander geometry, modify channel cross-sections, and establish a floodplain at the
existing stream elevation, thus, restoring a stable dimension, pattern and profile. This
restoration is based on analysis of current watershed hydrologic conditions, evaluation of
the project site, and assessments of stable reference reaches. The following
recommendations are included in this restoration plan:
• Form a stable channel with the proper dimension, pattern and profile.
• Establish a floodplain along the stream channel.
• Place natural material structures in the stream to improve stability and enhance
aquatic habitat.
• Stabilize stream banks with herbaceous and woody vegetation
1

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
1.1 PROJECT DESCRIPTION
The Middle Branch of Hewlett's Creek project site is located in Hanover County, North
Carolina. The project is fully contained within the property of one landowner (The Pine
Valley Country Club). The project reach is bounded by The Long Street Drainage Cannel
to the west (upstream) and a 78" RCP culvert for Robert E. Lee Drive to the east
(downstream) (Figure 1).
1.2 GOALS AND OBJECTIVES
This project has the following goals and objectives:
1. Restore 3527 linear feet of The Middle Branch of Hewlett's Creek (as measured
along the centerline)
2. Provide a stable stream channel that neither aggrades nor degrades while maintaining
its dimension, pattern, and profile with the capacity to transport its watershed's water
and sediment load.
3. Improve water quality and reduce further property loss by stabilizing eroding stream
banks.
4. Establish a new floodplain at the existing stream elevation.
5. Improve aquatic habitat with the use of natural material stabilization structures such
as root wads; log vanes, woody debris and a riparian buffer.
6. Provide aesthetic value, wildlife habitat and bank stability through the creation or
enhancement of a riparian zone.
1.3 STREAM SURVEY METHODOLOGY
The US Forest Service General Technical Report RM-245, Stream Channel Reference
Sites: An Illustrated Guide to Field Technique is used as a guide when taking field
measurements. Accurate field measurements are critical to determine the present
condition of the existing channel, conditions of the floodplain, and watershed drainage
patterns.
2
The Middle Branch of Hewlett's Creek
New Hanover County, NC
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Site Area Boundary
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New Hanover County, NC North, t ,
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Source: Now Hanover County GIS Department
FIGURE I
SITE LOCATION
RESTORATION PLAN
3
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
NCSU contracted with W. K. Dickson to conduct a topographic survey of the restoration
site in August 2002. This mapping along with field measurements taken by NCSU staff
was used to evaluate present conditions, new channel alignment and grading volumes.
Mapping also provided locations of property pins, large trees, vegetation lines, and
culverts, roads, utilities and elevation contours.
A windshield survey was also conducted to determine the existing conditions within the
watershed. The watershed is fully (>90%) developed with residential dwellings and has
an area of 1.5 sq. miles
During the site visits, three cross-sections were taken using standard differential leveling
techniques. These cross-sections were used to gather detail on the present dimension and
condition of the channel. Bankfull cross-sectional area was calculated using the bankfull
features, the bankfull area at riffles varied between 26 sgft to 31 sqft.
1.3.1 Stream Delineation Criteria - Classification
Dave Rosgen developed his stream classification system in order to accomplish the
following:
1) Predict a river's behavior
2) Develop specific hydraulic and sediment relationships for a given stream type and its
state
3) Provide a mechanism to extrapolate site-specific data.to stream reaches having
similar characteristics
4) Provide a consistent frame of reference for communicating stream morphology and
condition among a variety of disciplines and interested parties
The Rosgen Stream Classification System is based on five criteria: width/depth ratio,
entrenchment ratio, slope, sinuosity, and channel materials. All cross-sections were
classified using this system.
1.3.2 Bankfull Verification
The foundation of Dave Rosgen's classification system is the concept of bankfull stage,
which is the point of incipient flooding. The width/depth and entrenchment ratios
described above depend on the correct assessment of bankfull. If bankfull is incorrectly
determined in the field, the entire restoration effort will be based on faulty data. It is
important to verify the physical indicators observed in the field with either gage data or a
regional curve to ensure the correct assessment of the bankfull stage.
The bankfull stage is determined in the field using physical indicators. The following is a
list of commonly used indicators that define bankfull (Rosgen, 1996):
4
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
• The presence of a floodplain at the elevation of incipient flooding.
• The elevation associated with the top of the highest depositional feature (e.g. point
bars, central bars within the active channel). These depositional features are
especially good stage indicators for channels in the presence of terrace or adjacent
colluvial slopes.
• A break in slope of the bank and/or a change in the particle size distribution, since
finer material is associated with deposition by overflow, rather than deposition of
coarser material within the active channel.
• Evidence of an inundation feature such as small benches below bankfull.
• Staining of rocks.
The most dominant bankfull indicators along The Middle Branch of Hewlett's Creek are
high scour lines and breaks in slope along the backs of narrow point bars.
The most common method of verifying bankfull stage is to compare the field determined
bankfull stage with measured stages at a stream gauging station. This calibration can be
performed if there is a stream gage within the study area's hydro-physiographic region.
In un-gauged areas, Dave Rosgen recommends verifying bankfull with the development
of regional curves. The regional curves normally plot bankfull discharge (QbkD, cross-
sectional area, width, and depth as a function of drainage area. The cross-sectional areas
of The Middle Branch of Hewlett's Creek was plotted on the Urban, Coastal Regional
Curve of North Carolina developed by the North Carolina State University (NCSU)
Water Quality Group, 2003 to help verify bankfull stage.
Data obtained from field surveys was used to compute the morphological characteristics
shown on the graph. The cross-sectional area for The Middle Branch of Hewlett's Creek
plots along the trend line for the Urban Regional Curve. The bankfull cross-sectional area
for the design channel was determined from evaluating the North Carolina regional curve
relationships and comparing them to the reference reach sites surveyed near the
restoration site. HEC-RAS was used to verify the design cross-sectional area for the
project.
5
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.0 EXISTING CONDITIONS
2.1 WATERSHED
2.1.1 General Description of the Watershed
The Middle Branch of the Hewlett Creek is a second order stream, is located within the
Coastal Physiographic Province of the Cape Fear River Basin (USGS Cataloging Unit). 03 0 211')'
The watershed is located in the Southeast corner of Wilmington, in New Hanover
County, North Carolina. The headwaters of the project originate approximately 2 miles to
the north-northeast of the restoration site. From the headwaters, Hewlett flows for
approximately 4.0 miles before emptying into the Greenville Sound just southwest of
Masonboro inlet. The land use within the study is mixed residential, commercial, and an
18-hole golf course.
The watershed is approximately 1.5 square miles (Figure 2). The watershed is oriented
north to south bending to the east before the project site. The topography ranges from
gently sloping to flat with relatively flat former floodplain that has be detached by
channeling the stream the middle of the past century. Land surface elevations range from
approximately 30 to 55 feet above mean sea level.
2.1.2 Surface Waters Classification
Surface waters in North Carolina are assigned a classification by the DWQ that is
designed to maintain, protect, and enhance water quality within the state. Hewlett's Creek
(NCDWQ Stream Index Number) is classified as a class SA HQW water body
(NCDENR, 2001). SA HQW water resources are waters protected for shellfish
propagation and survival, fishing, wildlife, secondary recreation, and agriculture.
2.1.3 Soils of the Watershed
The soils found in the watershed and adjacent to the stream can help determine the bed
and bank materials occurring in the stream. The Rosgen stream classification system uses
average particle size within the bankfull channel to help classify the stream. Knowing the
make up of the soils in the watershed, assists in understanding the anticipated bed-load
and sediment transport capacity of the stream.
Soils in upland areas within the watershed consist primarily of sand and urban complex
(draft maps and descriptions of the soils in the project area - New Hanover County Soil
Survey Office, Natural Resources Conservation Service [NRCS]). Depth to bedrock is
mapped as greater than 60 inches for the soils in the watershed. Soils in the side slopes
shoulders and summits of ridges include Baymeade-Urban Land complex 1 to 6 percent
slopes, and Rimini sand 1 to 6 percent slopes
6
The Middle Branch of Hewlett's Creek
New Hanover County, NC
The Middle Branch of Hewlett's Creek
New Hanover County, NC North
0 0.125 025 11.5 075
OWES
SDI Ce: New Halmercm oycis Departneit
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FIGURE 2
WATERSHED ARIAL
RESTORATION PLAN
7
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.1.4 Land Use of the Watershed
Land use within the watershed is predominately urban residential (Figure 2). Evaluation
of a 1998 aerial photo obtained from New Hanover Country reveals that approximately
90% of the watershed is built out with single home residential areas, roads, businesses
and golf courses, with the remaining being water detention and forested urban land that is
not likely to be developed. The total percent impervious cover in the watershed is
approximately 20%-30%
2.2 RESTORATION SITE
The following sections provide a description of existing site conditions. This includes the
current stream conditions, soils, and surrounding plant communities.
2.2.1 Site Description
The Middle Branch of Hewlett's Creek restoration site begins approximately 4.0 miles
from its confluence with the Greenville Sound. The project is located within the property
boundaries of The Pine Valley Country Club. The middle Branch of Hewlett's Creek
flows from the west to east through a 0 to 35-foot wide floodplain. The majority of the
floodplain is located on the within the ditched channel of Hewlett's creek. The
floodplain typically ends abruptly at the toe of the adjoining steep slopes. A former
terrace extends along the entire length of the project and is 75 to 300 feet wide the
majority of the terrace is presently being used as fairway for the adjacent golf course.
The channel has long straight reaches with very minimal meanders. Channel sinuosity for
the entire reach is 1.05. High banks and areas of severe bank erosion can be found
throughout the project reach.
The main factor in the degradation and impairment for the Middle Branch of Hewlett's
Creek appears to be historic straightening of the channel and removal of riparian
vegetation. Straightening has increased the channel slope and decreased the stream
sinuosity. Erosion has caused increased sediment supply and channel widening. This has
combined to lead to the development of central bars in several straight sections of the
channel. Further development of central bars will increase erosion and lateral migration
of the channel.
2.2.2 Existing Stream Characteristics
Field surveys of the existing stream channel and site were conducted in August 2002.
The Middle Branch of Hewlett's Creek Restoration Site can be typically defined as a
predominantly straight channel with poor habitat. Stream banks are steep with areas of
active erosion. Long straight sections of the channel have central bars forming; indicating
the channel is over-wide. Instead of focusing the flow along the thalweg, the central bars
deflect the stream-flow toward the banks and accelerate bank erosion.
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
flow toward the banks and accelerate bank erosion.
Riffle bankfull widths range. from 24 to 30 feet with mean depths
ranging from 1.2 to 1.5 feet. The cross-sectional areas for these riffles range from 26.0 to
31.5 square feet. All of the cross-sections were taken within the reach to be restored. All
cross-sections classed as type-F or G channels as the amount of incision increases
downstream. The stream has the following average characteristics:
Bankfull Width: 27 feet
Bankfull Cross-sectional Area: 30 square feet
B ankfull Mean Depth: 1.3 feet
Bankfull Maximum Depth: 4.1 feet
Average Water Surface Slope: 0.002 feet/feet
Entrenchment Ratio: >6.0
Sinuosity: <1.05
Bank Height Ratio 2.0
The entire length of channel within the restoration site was rated using the Bank Erosion
Hazard Index (BEHI). The most likely bank to erode was assessed throughout the reach.
The reach was subdivided into sections with similar erosional characteristics such as
surface protection, root depth, root density, and bank angle. Results are listed in Table 1.
The overall restoration reach has a BEHI rating of high, although two sections had a
BHEI rating of very high and extreme. It is likely these two areas will expand as erosion
continues. The main cause of the very high and extreme ratings are due to the lack of
significant deep rooting vegetation and surface protection. Restoration will reestablish
deep rooting vegetation along the banks throughout the entire reach.
2.2.3 Soils of the Restoration Site
According to the preliminary soil maps for New Hanover County, soils adjacent to the
Middle Branch of Creek within the restoration site are mapped as Rimini, Baymeade and
Lynn Haven soils (Figure 3). Investigation of the soils adjacent to the stream indicates
that all three soils are present, although Lynn Haven is the most common. Lynn Haven is
a fine sandy soil that is well drained. These permeable soils occur on nearly level
floodplains along creeks and rivers. The original wetland soils where most likely covered
and removed when the golf course was built up and the creek was straightened
Soil textures encountered include sand and fine sand. The seasonal high water table was
observed to be greater than 40 inches for most soils within the project. Slopes range from
0 to 6 percent.
2.2.4 Terrestrial Plant Communities
The following sections describe the existing plant communities on and adjacent to the
restoration site. For purposes of this project, three plant communities are described:
Managed Land, Bottomland Forest, and Upland Hardwood Forest. Nomenclature follows
Radford (1968).
9

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The Middle Branch of Hewlett's Creek
New Hanover County, NC
The Middle Branch of Hewlett's Creek 'IT
New Hanover County, NC
NORTH
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M103
Source: New Hanover CourdyGlS Department
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FIGURE 3
SOILS MAP
RESTORATION PLAN
11
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.2.5 Wildlife Observations
Wildlife and signs of wildlife were noted during on-site visits, however, a formal wildlife
survey was not performed. Tracks of white tailed deer (Odocoileus virgin ianus) and
raccoon (Procyon Iotor) were observed along the stream banks. A variety of birds were
observed in the thickets and shrubs surrounding the stream channel and forest, including:
various sparrows.
2.2.5.1 Possible Invasive Wildlife
The following species were identified during site visits to the Middle Branch of Hewlett's
Creek; Asian tiger mosquito (Aedes albopictus), Bullfrog (Rana catesbeialta) (auditory
identification), European gypsy moth (Lymantria dispar), and European starling (Sturnus
vulgaris). The bullfrog is listed based on auditory identification by one of the project
researchers. The gypsy moth is listed based on visual identification of nests. The
mosquito and starling are listed due to their ubiquitous nature.
2.2.6 Endangered Species
The NCSU design team has not identified endangered plant or animal species or any such
habitat that would support the endangered species listed in this section. The NCSU
design team has made multiple visits to the Pine Valley Country Club and the restoration
site. Below is a list obtained from Natural Heritage, of the endangered of concern for
New Hanover County.
2.2.6.1 Endangered Flora
Vascular Plants:
Cooley's meadowrue
Rough-leaved loosestrife
Seabeach amaranth
Bog St. John's-wort
Carolina asphodel
Carolina bishopweed
Carolina beaksedge
Chapman's sedge
Coastal golden rod
"Dune bluecurls"
Pickering's dawnflower
Pondspice
Sandhills milkvetch
Savanna indigo-bush
Spiked medusa
Spring-flowering goldenrod
Tough bumelia
Endangered
Endangered
Threatened
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
12
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Venus flytrap Federal Species of Concern
2.2.6.2 Endangered Fauna
Vertebrates:
Red-cockaded woodpecker Endangered
Shortnose sturgeon Endangered
West Indian Manatee Endangered
American Alligator Threatened
Green sea turtle Threatened
Loggerhead sea turtle Threatened
Piping Plover Threatened
Carolina gopher frog Federal Species of Concern
Eastern painted bunting Federal Species of Concern
Mimic glass lizard Federal Species of Concern
Northern pine snake Federal Species of Concern
Southeastern myotis Federal Species of Concern
Southern Hognose snake Federal Species of Concern
Invertebrates:
Arogos skipper
Buchholz's dart mouth
Cape Fear threetooth
Croatan crayfish
Magnificent rams-horn
Rare skipper
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
13

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
3.0 REFERENCE REACHES
Reference reaches were utilized on which the morphological characteristics were
measured to determine a range of values for the stable dimension, pattern, and profile of
the proposed channel. The following sections include a detail of three of the reference
reaches that were used for design of the restoration plan for the Middle Branch of
Hewlett's Creek. The reference reaches used along with the bankfull area, and current
constraints as the base for the preliminary design.
3.1 JOHANNAH CREEK
The Johannah creek has a drainage area of 1.18 square miles. Angela Moreland of the
NCSU Water Quality group completed the stream survey of Johannah creek in the
summer of 2001. The stream had a bankfull channel width of 10.4 feet and a bankfull
mean depth of 0.8 feet. Johannah Creek is a C5 stream type from Rosgen Classification
system. The morphological characteristics of this reference stream are included in Table
2.
3.2 PANTHER BRANCH
The Panther branch has a drainage area of 1.69 square miles. Angela Moreland of the
NCSU Water Quality group completed the stream survey of Panther branch in the
summer of 2001. The stream had a bankfull channel width of 11.5 feet and a bankfull
mean depth of 1.6 feet. Panther Branch is an E5 stream type from Rosgen Classification
system. The morphological characteristics of this reference stream are included in Table
2.
3.3 BATORORA BRANCH
Angela Moreland of the NCSU Water Quality group completed the stream survey of
Batorora branch in the summer of 2001. The stream had a bankfull channel width of 15.5
feet and a bankfull mean depth of 1.5 feet. Batorora Branch is an E5 stream type from
Rosgen Classification system. The morphological characteristics of this reference stream
are included in Table 2.
15
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Table 2. Middle Branch of Hewlett's Creek Morphology (Existing,
Design, and Reference)
Parameter Existing Reference Reference Reference Design
Reach Name Hewlett Panther Johannah Batorora Hewlett
Bankfull XSEC Area, Abkf (ft) 30 17.9 8.6 23.9 30
Bankfull Width, Wbkf (ft) 20 11.5 10.4 15.5 19
Bankfull Mean Depth, Dbkf (ft) 1.5 1.6 0.8 1.5 1.6
Width to Depth Ratio, W/D (ft/ft) 13.3 7.4 12.6 10.1 12
Entrenchment Ratio, Wfpa/Wbkf (ft/ft) 2 17.4 19.2 12.9 3
Bank Height Ratio, Dtob/Dmax (ft/ft) 2.0 1 1 1 1
Min Bkf Max Depth, Dmax (ft) 1.6 --- --- --- 2.1
Max Bkf Max Depth, Dmax (ft) 1.9 --- --- --- 2.8
Min Bkf Max Depth, Dmax/Dbkf 1.1 1.6 1.3 1.4 1.3
Max Bkf Max Depth, Dmax/Dbkf 1.3 1.8
Min Meander Length, Lm (ft) 100 --- --- --- 86
Max Meander Length, Lm (ft) 280 --- --- --- 171
Min Meander len Ratio, Im/Wbkf 5 2.3 1.9 4.1 4.5
Max Meander Len Ratio, Lm/Wbkf 14 9.1 5.1 6.8 9
Min Radius of Curvature, Rc (ft) 60 --- --- --- 34
Max Radius of Curvature, Rc (ft) 80 --- --- -- 49
Min Rc Ratio, Rc/Wbkf 3 0.5 0.9 0.7 1.8
Max Rc Ratio, Rc/Wbkf 4 1.5 2.3 2.6 2.6
Min Belt Width, Wblt (ft) 25 --- --- --- 42
Max Belt Width, Wblt (ft) 40 --- --- --- 76
Min MW Ratio, Wblt/Wbkf (ft) 1.3 1.9 1.3 2.9 2.2
Max MW Ratio, Wblt/Wbkf (ft) 2 8.7 4.4 4.5 4
Sinuosity, K 1.05 1.2 1.2 1.2 1.2
Valley Slope, Sval (ft/ft) .0026 .0040 .0026 .0061 .0026
Channel Slope, Schan=SvaVK (ft/ft) .0025 .0033 .0021 .0051 .0021
Pool Slope, Spool (ft/ft) 0 --- --- --- 0
Pool Slope Ratio, Spool/Schan 0 0 0 0
Min Pool Depth, Dpool (ft) 1.7 --- --- --- 2.4
Max Pool Depth, Dpool (ft) 2 --- --- --- 3.0
Min Pool Depth Ratio, DpooVDbkf 1.1 1.6 1.9 2 1.5
Max Pool Depth Ratio, DpooVDbkf 1.3 2
Min Pool Width, Wpool (ft) 21 --- -- - 19
Max Pool Width, Wpool (ft) 25 --- - - 22.8
Min Pool Wid Ratio, Wpool/Wbkf 1.1 1 1.2 0.9 1
Max Pool Wid Ratio, Wpool/Wbkf 1.3 1.2
Min Length Pool Spacing, Lps (ft) 40 --- - - 57
Max Length Pool Spacing, Lps (ft) 220 --- --- --- 114
Min Pool Spacing Ratio, Lps/Wbkf 2 1.3 1.2 1.7 3
Max Pool Spacing Ratio, Lps/Wbkf 11 5.7 3.8 3.9 6
16
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.0 STREAM CHANNEL DESIGN
This restoration will classify as a Priority 2 restoration (Rosgen, 1997). The floodplain
will be re-established to fit the existing or slightly raised stream profile. The grade of the
stream will be raised in some areas and a floodplain will be established at the new
bankfull elevation. Table 3 describes and summarizes the four priorities of incised river
restoration (Rosgen, 1997). The proposed stream restoration will restore the natural
meander pattern, modify channel cross-section restore bedform, improve sediment
transport capacity, enhance habitat, and re-establish a floodplain for the stream.
The design was based upon Dave Rosgen's natural channel design methodology. As
described in Section 3.0, reference reaches were utilized on which the morphological
characteristics were measured to determine a range of values for the stable dimension,
pattern, and profile of the proposed channel. The measured and proposed morphological
characteristic's are shown in Table 2.
A conceptual design was developed from the range of values listed in Table 2. This
stream restoration project will result in approximately 3,600 restored linear feet (as
measure from the thalweg) of The Middle Branch of Hewlett's Creek. The plan view of
the proposed restoration design can be seen in Figures 4, 5 and 6.
17
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Table 3. Priorities, Description and Summary for Incised River Restoration
DESCRIPTION METHODS ADVANTAGES DISADVANTAGES
PRIORITY i Re-establish channel on Re-establishment of 1) floodplain re-
Convert G and/or F previous floodplain using relic floodplain and stable establishment could cause
stream types to C and/or channel or construction of channel: flood damage to urban
E at previous elevation new bankfull discharge 1) reduces bank height and agricultural and industrial
w/floodplain channel. Design new channel streambank erosion development.
for dimension, pattern and 2) reduces land loss 2) downstream end of
profile characteristic of stable 3) raises water table project could require grade
form. Fill in existing incised 4) decreases sediment control from new to
channel or with discontinuous 5) improves aquatic and previous channel to prevent
oxbow lakes level with new terrestrial habitats head-cutting.
floodplain elevation. 6) improves land
productivity, and
7) improves aesthetics.
PRIORITY2 If belt width provides for the 1) decreases bank height 1) does not raise water
Convert G and/or F minimum meander width ratio and streambank erosion table back to previous
stream types to C or E. for C or E stream types, 2) allows for riparian elevation
Re-establishment of construct channel in bed of vegetation to help stabilize 2) shear stress and velocity
floodplain at existing or existing channel, convert banks higher during flood due to
higher, but not at existing bed to new 3) establishes floodplain to narrower floodplain
original level floodplain. If belt width is too help take stress of channel 3) upper banks need to be
narrow, excavate streambank during flood sloped and stabilized to
walls. End-hall material or 4) improves aquatic habitat reduce erosion during
place in streambed to raise 5) prevents wide-scale flood.
bed elevation and create new flooding of original land
floodplain in the deposition. surface
6) reduces sediment
7) downstream grade
transition for grade control
is easier.
PRIORITY 3 Excavation of channel to 1) reduces the amount of 1) high cost of materials
Convert to a new stream change stream type involves land needed to return the for bed and streambank
type without an active establishing proper river to a stable form. stabilization
floodplain, but dimension, pattern and 2) developments next to 2) does not create the
containing a floodprone profile. To convert G to B river need not be re-located diversity of aquatic habitat
area. Convert G to B stream involves an increase in due to flooding potential 3) does not raise water
stream type, or F to Be width/depth and entrenchment 3) decreases flood stage for table to previous levels.
ratio, shaping upper slopes the same magnitude flood
and stabilizing both bed and 4) improves aquatic
banks. A conversion from F habitat.
to Be stream type involves a
decrease in width/depth ratio
and an increase in
entrenchment ratio.
PRIORITY 4 A long list of stabilization 1) excavation volumes 1) high cost for
Stabilize channel in materials and methods have reduced stabilization
place been used to decrease stream 2) land needed for 2) high risk due to
bed and bank erosion, restoration is minimal excessive shear stress and
including concrete, gabions, velocity
boulders and bio-engineering 3) limited aquatic habitat
methods depending on nature of
stabilization methods used.
Source: Rosgen, 1997, "A Geomorphological Approach to Restoration of Incised Rivers"
18

CITY OF WILMINGTON STORMWATER POND
7VPCR VRY SILT FrNC.
" ??5'S+C .nit t (C-bJ
• 4
STAGING AND STOCKPILE AREA
2.75 acres

1.) Area shall be graded smooth upon completion of earthwork activities, with a
slope toward the storm water pond and a maximum side slope of 3:1
2.) Area shall be stabilized with temporary seed upon completion of earthwork
3.) Area shall be sprigged with Bermuda grass variety between May 15th and
June 15th, the contractor shall coordinate with the golf course superintendent
LEGEND
CROSS VANE * CART PATH

'S.. D.t.l 13 (C-B) 'Set D.t.1 IS (C-e)
LOG VANE * CULVERT CROSSING

•Se. Detail 11 C-8 'See Det 1 7 C-7
ROOT WADS * RETAINING WALL

<
•See Delol 12 (C-e -Se. D.t.l 16 C-S
NOTE: Structure placement on Plan Sheets
are for location only. Actual placement shall
be directed by Resident Engineer
DETAIL
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CURVE LENGTH RADIUS
C- 1 59.6 39.5
C- 2 .223 32.0
C- 3 49.8 34.0
C- 4 25.0 34.0
C- 5 43.3 39.0
C- 8 72.1 42.0
C- 7 6&1 3&0
C- 8 69.2 42.0
C- 9 3&9 38.0
C- 10 29.0 40.0
C- 11 5&7 43.0
C- 12 43.7 3&0
C- 13 J8.8 33.0
C- 14 38.1 34.0

NOTE: The listed Radius of Curvatures are
measured from the stream centerline.
Actual Radius of Curvatures maybe
adjusted by Resident NCSU Engineer
i
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LINE TABLE
LINE LENGTH BEARING NORTHING EASTING
L- 1 25.5 N TI '58 161485 2332861
L- 2 31.9 N T40'33"W 161518 2332892
L- 3 31.9 N13 '53"W 181554 2332951
L- 4 53.9 N38'19' 151607 2332952
L- 5 3&5 N44 "W 161691 2332983
L- 5 19.4 M326'1 151780 2332973
L- 7 37.5 N V6' "W 151932 2333028
L- 6 41.9 ' 3"W 151914 2333054
L- 9 29.6 N T 161921 2333125
L- 10 424 N7M'16' 151972 2-IM159
L- 11 35.9 N1 -,V18'W 162066 2333275
L- 12 30.3 MS 44" 182150 2333293
L- 13 24.4 N1 DB' 'W 162192 2333344
L- 14 31.7 MD'48'4T 162248 2333357
NOTE: The listed Northing and Easting Columns
represent the head of the appropriate riffle section
along the centerline of the stream. Actual riffle
starting locations. bearing and lengths maybe adjusted
by Resident NCSU Engineer

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LEGEND
CROSS VANE * CART PATH

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RO
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NOTE: Structure placement on Plan Sheets
are for location only. Actual placement shall
be directed by Resident Engineer
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CURVE LENGTH RADIUS
C- 15 37.3 42.0
C- 18 310 40.0
C- 17 57.6 34.0
C- 18 5&1 30.0
C- 19 57.7 3000
C- 20 56.4 30.0
C- 21 27.2 35.0
C- 22 17.0 38.0
C- 23 30.0 35.0
C- 24 32.5 38.0
C- 25 34.2 35.0
C- 25 44.9 37.0
C- 27 34.8 310
C- 25 59.4 39.0
NOTE: The listed Radius of Curvatures are
measured from the stream centerline.
Actual Radius of Curvatures maybe
adjusted by Resident NCSU Engineer
CLAY PWG
SEE DETAIL 9 (C-7)
STREAM (SREV)
UNE TABLE
LINE LENGTH BEARING NORTHING EASTINC
L- 15 27.1 NW' 15'447W 2333402
L- 16 57.8 162347 2333411
L- 17 33.5 182411 2333472
L- 18 34-4 182482 2333500
L- 19 311 162520 2333582
L- 20 213 1' 182587 2333583
L- 21 25.8 182613 2333641
L- 22 25.2 182663 2333630
L- 23 18-51 N79'16'03'E 182768 2333652
L- 24 26.2 162788 2333664
L- 25 21L6 152777 2333938
L- 26 28w1 N 162798 2333991
L- 27 30.1 N4 a 162753 2334145
L- 28 29.0 162600 2334110
L- 29 29.8 N 182776 2334153
NOTE: The listed Northing and Easting Columns
represent the head of the appropriate riffle section
along the centerline of the stream. Actual riffle
starting locations, bearing and lengths maybe adjusted
by Resident NCSU Engineer

REPUCEMENT CART PAM
SEE DETAIL IS (C-9)
LEGEND
CROSS VANE * CART PATH

-See Det.R 13 C-8) Ka Detc9 15 (C-8
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Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Existing pattern measurements were taken from the topographic mapping. A stable
pattern will be established by establishing new meanders along the channel. This will be
achieved by introducing meanders into the stream with radius of curvatures and lengths
based on reference reach data and the existing constraints. The maximum stream length
and sinuosity has been designed into the new channel based on the reference data and
project constraints. Introduction of these meanders will improve habitat while lowering
slope and shear stress.
• 4.1.3 Bedform
The existing bedform along the Middle Branch of Hewlett's Creek is in poor condition.
Long, straight sections of the channel consist of predominantly run bedform features. The
design channel will incorporate ripples and pools to provide bedform common to E5
stream types. Pools will be located in the outside of meander bends with riffles in the
inflection points between meanders. The ripples will have a thalweg depth of 1.6 feet
while the pools will be deeper with a maximum depth of 3.0 feet. A graph of the
proposed profile can be seen in Figure 8. The profile may be adjusted slightly during the
final design phase of the project.
Cross-vanes will be utilized as grade control structures and to tie the relocated sections
back into the existing channel. The cross vanes will be constructed out of natural
materials such as wood and some boulders.
The existing pool-to-pool spacing is impaired in areas due to tight meander geometry.
The proposed spacing is 57 to 114 feet, which is within the range of 3 and 6 bankfull
widths as determined from the reference reach data. To accomplish this, pools will be
realigned or constructed such that they will be located in the outside of the meander
bends. Bedform will also be addressed through the strategic placement of natural material
structures such as cross vanes, root wads and large woody debris. Modifications to the
bedform will provide stability and habitat to the channel.
4.1.4 Riparian Areas
A riparian zone will be created around the new proposed stream channel to enhance both
aquatic and terrestrial habitat as well as stabilize the stream channel. The riparian zone
will extend at least 15 feet on either side of the channel from the top of bank. Were ever
possible the riparian zone will extend at least 25 feet on either side of the channel. These
areas will be planted with appropriate riparian vegetation as described in Section 6.0
Habitat Restoration. The riparian zone is limited by the urban constraints and the
constraints of an active golf course that includes play that cross the stream channel.
23
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Figure 7: Typical Cross-Sections
Typical X-Section Riffle
34.00
32.00
30.00 0
28.00
a?
26.00 w
24.00
-60.00 -40.00 -20.00 0.00 20.00 40.00 60.00
Off Set from CL (ft)
Typical X-Section Pool
-80 -60 -40 -20 0
Off Set from CL (ft)
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31.0
29.0 0
27.0 >
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Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.2 SEDIMENT TRANSPORT
A stable stream has the capacity to move its sediment load without aggrading or
degrading. The total load of sediment can be divided into bed load and wash load. Wash
load is normally composed of fine sands, silts and clay and transported in suspension at a
rate that is determined by availability and not hydraulically controlled. Bed load is
transported by rolling, sliding, or hopping (saltating) along the bed. At higher discharges,
some portion of the bed load can be suspended, especially if there is a sand component in
the bed load. Bed material transport rates are essentially controlled by the size and nature
of the bed material and hydraulic conditions (Hey 1997).
Critical dimensionless shear stress can be found using Shield's Curve and surface particle
sample from a representative riffle in the reach. A riffle bed surface pebble count was
taken at a riffle on the Middle Branch of Hewlett's Creek. The riffle bed surface d50 was
then calculated to be 0.06 mm. The shear stress placed on the sediment particles is the
force that entrains and moves the particles, in a given channel geometry. From Shields
curve the shear stress that entrains and moves particles in this stream based on the d50 is
.00251bs/sqft.
Wetted perimeter was measured off of a CADD file of the typical riffle cross-section
drawn to scale. The wetted perimeter was measured to be 29 ft, while the cross-sectional
area was 30 sgft this produced a hydraulic radius of 1.03. The Slope for the used for the
shear stress calculation is 0.0023. The resultant shear stress for the proposed channel is
0.15 lbs/sgft, this shear stress is sufficient to move the d84 of the riffle bed material,
which is 0.15 mm. Shield's Curve predicts that this stream can move a particle that is, on
average, greater than 5 mm. Since the D84 was 0.15 mm and Shield's Curve predicts 5
mm, the proposed stream has the competency to move its bed load.
Sediment transport analysis was examined at the restoration site through the comparison
of existing and post restoration shear stress analysis. The existing channel does not
appear to be aggrading so it is implied that it is more capable of transporting its
watershed sediment load. Two existing shear stresses are examined and one restored
shear stress. Shear stress is approximated using the equation shear stress = density of
water times the hydraulic radius times the average water surface slope. Existing bankfull
shear stress is 0.2331bs/sqft. The top of bank shear stress is 0.454 lbs/sqft.
Post restoration, average water surface slope will be decreased and the floodplain will be
established adjacent to the bankfull channel thus lowering the top of bank shear stress
significantly. The post restoration bankfull shear and top of bank shear stress is 0.222
lbs/sgft. These calculations were confirmed with HEC-RAS modeling.
4.3 FLOODING ANALYSIS
This restoration site is not in a mapped FEMA regulatory floodway zone and therefore, is
not subject to FEMA regulations. NCSU design team has also received verification from
26
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
the City of Wilmington Division of Stormwater that this reach of Hewlett's Creek is not
FEMA mapped and does not have a recorded history of flood related incidents. Currently
there are no structures located in the adjacent areas that would be impacted by floodplain
alterations. The Priority 2 restoration of the stream will leave the stream's existing profile
elevations essentially the same. A new floodplain will be established so that the active
stream will be able to access it during larger storm events. Considering the type of
restoration it is assumed that for smaller events the water surface elevations along the
stream shall remain the same. During storms where the stream accesses the newly
establishment floodplain the new water surface elevations are expected to be lower than
the existing water surface elevations of storms of the same magnitude. The restoration
will create neither positive nor negative water surface elevation changes during the larger
storm events (greater than 25-year). HEC-RAS was used to analyze both existing and
proposed conditions after the design was finalized. Sheer stress and flood stages were
compared at various return intervals to evaluate the design.
4.4 STRUCTURES
Several different structures made of natural materials will be installed along the Middle
Branch of Hewlett's Creek. These structures include cross vanes, single vanes, and root
wads. Natural materials such rocks and root wads will be used to create these structures
from off-site sources and on-site sources.
4.4.1 Cross Vane
A cross vane structure serves to maintain the grade of the stream. The design shape is
roughly that of the letter "U' with the apex located on the upstream side at the foot of the
riffle. Footer rocks are placed in the channel bottom for stability. Rocks or logs are then
placed on these footer rocks in the middle of the channel at approximately the same
elevation as the ripple. On either side of the channel, rocks or logs are placed at an angle
to the stream bank, gradually inclining in elevation until they are located above the
bankfull surface directly adjacent to the stream bank. Water flowing downstream is
directed over the vane towards the middle of the channel. Rocks or a log placed at the
apex determine the bed elevation upstream. A cross vane is primarily used for grade
control and to protect the stream banks.
4.4.2 Root Wads
The objectives of these structure placements are as follows: (1) protect the stream bank
from erosion; (2) provide in-stream and overhead cover for fish; (3) provide shade,
detritus, terrestrial insect habitat: (4) look natural, and (S) provide diversity of habitats
(Rosgen 1996). A footer log and boulder are placed on the channel bottom abutting the
stream bank along an outside meander that will provide support for the root wad and
additional stability to the bank. A large tree root wad is then placed on the stream bank
with additional boulders and rocks on either side for stability. Flowing water is deflected
away from the bank and towards the center of the channel.
27
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.4.3 Single Vane
A single vane structure serves to maintain the pattern of the stream. Footer rocks are
placed in the channel bottom for stability. Rocks or logs are then placed on these footer
rocks in the middle of the channel at approximately the same elevation as the ripple. On
either side of the channel, rocks or log is placed at an angle to the stream bank, gradually
inclining in elevation until they are located above the bankfull surface directly adjacent to
the stream bank. Water flowing downstream is directed over the vane towards the middle
of the channel. A single vane is primarily used to turn the stream flow and control and to
protect the stream banks.
Specific location of these structures will be determined during final design.
28
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
5.0 HABITAT RESTORATION
The restoration plan requires the establishment of riparian vegetation at the site. The
proposed vegetation is described in the following sections.
5.1 VEGETATION
Vegetation that develops a quick canopy, has an extensive root system, and a substantial
above-ground plant structure is needed to help stabilize the banks of a restored stream
channel in order to reduce scour and runoff erosion. In natural riparian environments,
pioneer plants that often provide these functions are alder, river birch, silky dogwood,
and willow. Once established, these trees and shrubs create an environment that allows
for the succession of the other riparian species including ashes, black walnuts, red
maples, sycamores, oaks, and other riparian species.
In the newly restored stream channel, revegetation will be vital to help stabilize the
stream banks and establish a riparian zone around the restored channel. Revegetation
efforts on this project will emulate natural vegetation communities found along relatively
undisturbed stream corridors. To quickly establish dense root mass along the channel
bank, a native grass mixture will be planted on the streambed and bank. Shrubs will be
utilized on the stream bank and along the floodplain to provide additional root mass.
Extra care will be given to the outside of the meander bends to ensure a dense root mass
in those areas of high stress. Coir matting or similar material will be used to provide
erosion protection until vegetation can be established. Along the tops of the channel
banks, trees, shrubs and a native grass mixture will be planted.
A mixture of seeds, live stakes, bare root, as well as balled in burlap nursery stock, some
2 "- 4" caliper tree and transplants will be used to stabilize the banks. Proposed species
to be planted included, but are not limited to:
Trees
Blackcherry (Prunus serotina)
Blackgum (Nyssa sylvatica)
Loblolly Bay (Gordonia lasianthus)
River Birch (Betula nigra)
Sugarberry (Celtis laevigata)
Shrubs
American hornbeam (Carpinus caroliniana)
Fetter bush (Lyonia lucida)
Inkberry (Ilex glabra)
Marsh mallow (Hibiscus moscheutos)
Silky dogwood (Corpus amomum)
Sweet pepperbush (Clethra alnifolia)
Virginia willow (Itea virginica)
29
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Herbs- Permanent seed mixture
Deertongue (Panicum clandestinum)
Purple love grass (Ergrostis spectabilis)
Switch Grass (Panicum virgatum)
Tussock sedge (Carex stricta)
Other herbaceous vegetation
Dwarf spike-rush (Eleocharis parvula)
Ironweed (Vernonia noveboracensis)
Jack-in-the-pulpit (Arisaema triphyllum)
Woody vegetation will be planted between February and May to allow plants to stabilize
during the dormant period and set root during the spring season. In the areas where
invasive and exotic species are located, during construction and monitoring control by
removal or appropriate herbicides will be implemented to prevent competition with the
revegetation efforts.
5.2 RIPARIAN BUFFERS
At least three different types of riparian buffers will be employed to vegetate the restored
channel. All buffers will use plants native to the coastal plain region of North Carolina.
In areas where the fairways cross the stream channel, vegetation will be kept to a minimal
height so as not to obstruct views and play within the crossing. The areas along the city
sewer line (within approximately 10' to either side of the utility) will be planted with
vegetation having shallow (limited) root structure so that the sewer line and access to it
shall not be impacted or impeded. The remaining areas will be planted with native trees,
shrubs, grasses and other herbaceous vegetation in order to restore natural coastal plain
plant communities. Proposed species to be planted include but are not limited to those
listed in the above section
5.2.1 Temporary Seeding
A temporary seed mixture will be applied to all disturbed areas immediately after
construction activities have completed. This temporary seed mixture will provide erosion
control until permanent seed can become established. Permanent seed will be native to
the coastal region of North Carolina.
30
,k
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
6.0 MONITORING
6.1 STREAM CHANNEL
Monitoring of the stability of the channel is recommended to occur approximately 6
months after restoration is complete or after bankfull (or greater) events and should
continue annually for a period of 3 to 5 years. Monitoring practices may include, but are
not limited to, installing bank erosion pins and a toe pin, monumented cross-sections,
scour chains, macroinvertebrate studies, longitudinal profiles, conducting the bank
erosion hazard rating guide and establishing photo reference points. The purpose of
monitoring is to determine bank stability, bed stability, morphological stability and
overall channel stability. Table 4, below, can be used for selecting practices.
Table 3. - Stream Monitoring Practices
PRACTICE STABILITY ASSESSMENT
Bank Erosion Pins with Toe Pin -Lateral or bank stability
Monumented Cross-Section -Vertical or bank stability
-Lateral or bank stability
Scour Chains -Vertical or bed stability
-Scour depth fora articular storm
Scour Chain w/ Monumented
Cross-Section -Vertical or bed stability
-Sediment transport relations
-Biological interpretations
Longitudinal Profile -Channel profile stability
Bank Erosion Hazard Guide -Bank erosion potential
Photo Reference Points -Overall channel stability
Macroinvertebrate -Biological indication of water quality
6.2 VEGETATION
Prior to planting, the site will be inspected and checked for proper elevation and
suitability of soils. Availability of acceptable, good quality plant species will be
determined. The site will be inspected at completion of planting to determine proper
planting methods, including proper plant spacing, density, and species composition.
Competition control will be implemented if determined to be necessary during the early
stages of growth and development of the tree species. Quantitative sampling of the
vegetation will be performed between August 1 and November 30 at the end of the first
year and after each growing season until the vegetation criteria is met.
In preparation for the quantitative sampling, 50 by 50 feet (0.05-acre) vegetative plots
will be established in the reforested area. Plots will be evenly distributed throughout the
31
. P. .
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
site. For each plot, species composition and density will be reported. Photo points will be
taken within each zone. Monitoring will take place once each year for five years.
Success will be determined by survival of target species within the sample plots. At least
six different representative tree species should be present on the entire site. If the
vegetative success criteria are not met, the cause of failure will be determined and
appropriate corrective action will be taken.
6.3 MACROIN VERTEBRATES
A monitoring period of 3 to S years is commonly suggested to determine changes in
macroinvertebrate populations within a newly restored stream. The North Carolina
Wetlands Restoration Program will determine a macroinvertebrate monitoring policy.
32
V r"P .
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
7.0 REFERENCES
Amoroso, J.L., ed. 1999. Natural Heritage Program List of the Rare Plant Species of
North Carolina. North Carolina Natural Heritage Program, Division of Parks and
Recreation, North Carolina Department of Environment and Natural Resources. Raleigh,
North Carolina.
Cowardin, L.M., V. Carter, F.C. Gold and E.T. LaRoe. 1979. Classification of Wetlands and
Deepwater Habitats of the United States. U.S. Fish and Wildlife Service, Office of
Biological Services, FWS/OBS-79/3 I. U.S. Department of the Interior, Washington, DC.
Choate, J.R., J.K. Jones, Jr., and C. Jones. 1994. Handbook of Mammals of the South-Central
States. Louisiana State University Press, Baton Rouge, Louisiana.
Doll, B. A., et al. 2000. Hydraulic Geometry Relationships for Urban Streams throughout the
Piedmont of North Carolina. American Water Resources Association.
Godfrey, R.K., and J.W. Wooten. 1979. Aquatic and Wetland Plants of Southeastern United States.
Monocotyledons. The University of Georgia Press, Athens, Georgia.
Godfrey, R.K., and J.W. Wooten. 1981. Aquatic and Wetland Plants of Southeastern United States.
Dicotyledons. The University of Georgia Press, Athens, Georgia.
Harrelson, Cheryl, C.L. Rawlins and John Potyondy. 1994. Stream Channel Reference Sites: An
Illustrated Guide to Field Technique. United States Department of Agriculture, Forest Service.
General Technical Report RM-245.
Hey, Richard and Dave Rosgen. 1997. Fluvial Geomorphology for Engineers. Wildland Hydrology,
Pagosa Springs, Colorado.
LeGrand, H.E., Jr. and S.P. Hall, eds. 1999. Natural Heritage Program List of the Rare
Animal Species of North Carolina. North Carolina Natural Heritage Program, Division of
Parks and Recreation, North Carolina Department of Environment and Natural
Resources. Raleigh, North Carolina.
NCDENR. "Water Quality Stream Classifications for Streams in North Carolina." Water Quality
Section. http:/Ih2o.enr.state.nc.us/wghome.html (16 July 2001).
Radford, A.E., H.E. Ahles and G.R. Bell. 1968. Manual of the Vascular Flora of the Carolinas. The
University of North Carolina Press, Chapel Hill, North Carolina.
Rosgen, Dave. 1997. A Geomorphological Approach to Restoration of Incised Rivers.
Wildland Hydrology. Proceedings of the Conference on Management of Landscapes
Disturbed by Channel Incision.
33
V

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Schafale, M. P. and A. S. Weakley. 1990. Classification of the Natural Communities of
North Carolina: Third Approximation. North Carolina Natural Heritage Program.
Raleigh, North Carolina
United States Department of Agriculture - Soil Conservation Service. December, 1977. "Soil
Survey of Guilford County, North Carolina." US Government Printing Office, Washington,
DC.
United States Fish and Wildlife Service. "Region 4, Southeast Region/Endangered Species." North
Carolina Ecological Services. http://nc-es.fws.gov/ (August 2001).
USDA, NRCS. 2001. The PLANTS Database, Version 3.1 (http://plants.usda.gov). National Plant
Data Center, Baton Rouge, LA 70874-4490 USA.
34
Y
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.2.5 Wildlife Observations
Wildlife and signs of wildlife were noted during on-site visits, however, a formal wildlife
survey was not performed. Tracks of white tailed deer (Odocoileus virgin ialius) and
raccoon (Procyon Iotor) were observed along the stream banks. A variety of birds were
observed in the thickets and shrubs surrounding the stream channel and forest, including:
various sparrows.
2.2.5.1 Possible Invasive Wildlife
The following species were identified during site visits to the Middle Branch of Hewlett's
Creek; Asian tiger mosquito (Aedes albopictus), Bullfrog (Rana catesbeiana) (auditory
identification), European gypsy moth (Lymantria dispar), and European starling (Stunius
vidgaris). The bullfrog is listed based on auditory identification by one of the project
researchers. The gypsy moth is listed based on visual identification of nests. The
mosquito and starling are listed due to their ubiquitous nature.
2.2.6 Endangered Species
The NCSU design team has not identified endangered plant or animal species or any such
habitat that would support the endangered species listed in this section. The NCSU
design team has made multiple visits to the Pine Valley Country Club and the restoration
site. Below is a list obtained from Natural Heritage, of the endangered of concern for
New Hanover County.
2.2.6.1 Endangered Flora
Vascular Plants:
Cooley's meadowrue
Rough-leaved loosestrife
Seabeach amaranth
Bog St. John's-wort
Carolina asphodel
Carolina bishopweed
Carolina beaksedge
Chapman's sedge
Coastal golden rod
"Dune bluecurls"
Pickering's dawnflower
Pondspice
Sandhills milkvetch
Savanna indigo-bush
Spiked medusa
Spring-flowering goldenrod
Tough bumelia
Endangered
Endangered
Threatened
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
12
- I

lip
ITYSECTIOA,
Stream Restoration Plan
Hewlett's Creek
New Hanover County, North Carolina
Sept 22, 2003

BIOLOGICAL & AGRICULTURAL ENGINEERING
Weaver Labs Campus Box 7625
North Carolina State University
Raleigh, NC 27695
N.C eilands 6rad'l
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M?DENI
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
TABLE OF CONTENTS
1.0 INTRODUCTION ............................................................1
1.1 PROJECT DESCRIPTION ..........................................2
1.2 GOALS AND OBJECTIVES ........................................2
1.3 STREAM SURVEY METHODOLOGY ...........................2
1.3.1 Stream Delineation - Classification .........................4
1.3.2 Bankfull Verification ..........................................4
2.0 EXISTING CONDITIONS ...................................................6
2.1 WATERSHED .........................................................6
2.1.1 General Description of the Watershed .................... ..6
2.1.2 Surface Waters Classification ................................6
2.1.3 Soils of the Watershed .........................................6
2.1.4 Land Use of the Watershed ................................. ..8
2.2 RESTORATION SITE .............................................. ..8
2.2.1 Site Description .............................................. ..8
2.2.2 Existing Stream Characteristics ............................ ..8
2.2.3 Soils of the Restoration Site ................................ ..9
2.2.4 Terrestrial Plant Communities .............................. ..9
2.2.4.1 Managed Land ......................................12
2.2.4.2 Bottomland Forrest ............................... 12
2.2.4.3 Upland Hardwood Forest ........................ 12
2.2.4.4 Possible Invasive Flora ........................... 12
2.2.5 Wildlife Observations ........................................ 13
2.2.5.1 Possible Invasive Wildlife .......................... 13
2.2.6 Endangered Species ........................................... 13
2.2.6.1 Endangered Flora .................................. 13
2.2.6.1 Endangered Fauna ................................. 14
3.0 REFERENCE REACHES ...................................................15
3.1 JOHANNAH CREEK ...............................................15
3.2 PANTHER BRANCH ...............................................15
3.3 BATORORA BRANCH ............................................15
4.0 STREAM CHANNEL DESIGN ...........................................17
4.1 RESTORATION TECHNIQUES .................................22
4.1.1 Dimension ......................................................22
4.1.2 Pattern ..........................................................22
4.1.3 Bedform ........................................................23
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.1.4 Riparian Areas ................................................23
4.2 SEDIMENT TRANSPORT . ........................................26
4.3 FLOODING ANALYSIS ...........................................26
4.4 STRUCTURES ............... ........................................27
4.4.1 Cross Vane ............. ........................................27
4.4.2 Root Wads ............. ........................................27
4.4.3 Single Vanes ........... ........................................28
5.0 HABITAT RESTORATION ...............................................29
5.1 VEGETATION .......................................................29
5.2 RIPARIAN BUFFERS ..............................................30
5.2.1 Temporary Seeding ..........................................30
6.0 MONITORING ............................................................... 31
6.1 STREAM CHANNEL ...............................................31
6.2 VEGETATION .......................................................31
6.3 MACROINVERTEBRATES .......................................32
7.0 REFERENCES ...............................................................33
LIST OF TABLES
1
Table 1. Bank Erosion Potential ...............................................
Table 2. Middle Branch of Hewlett's Creek Morphology .................16
Table 3. Priorities, Desc. & Summary for Incised River Restoration... 18
Table 4. Stream Monitoring Practices .......................................31
LIST OF FIGURES
Figure 1 Site Location ............................................................3
Figure 2 Watershed Arial ...................................................... ..7
Figure 3 Soils Map .............................................................. 11
Figure 4 Hewlett's Creek Restoration Plan .................................. 19
Figure 5 Hewlett's Creek Restoration Plan ................................. 20
Figure 6 Hewlett's Creek Restoration Plan .................................. 21
Figure 7 Typical Cross-Sections .............................................. 24
Figure 8 Proposed Longitudinal Profile ...................................... 25
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
1.0 INTRODUCTION
The North Carolina Wetlands Restoration Program (NCWRP) has identified The Middle
Branch of Hewlett's Creek as a potential stream restoration site. Hewlett's Creek drains
into the Greenville Sound, the Middle Branch of Hewlett's creek (NCDWQ Stream Index
Number 18-87-26 SA HQW) is located on urban land in the southeast corner of
Wilmington in New Hanover County, North Carolina (Figure 1).
Arcadis first identified Hewlett's Creek as a potential restoration site in a feasibility
report to NCWRP. NCSU is completing the design and will conduct construction
oversight of the restoration of the middle branch of Hewlett's Creek. The portion of
Hewlett's creek that is being evaluated for restoration is within the property boundaries
of the Pine Valley Country Club. The Country Club Membership met on March 17`h of
2003 and voted to allow WRP to fund a restoration project focused on the Middle Branch
of Hewlett's Creek.
The Middle Branch of Hewlett's Creek has areas of significant active bank erosion
throughout the proposed project limits. There is evidence of historic straightening and
degradation resulting from this straightening. Thinning and removal of riparian
vegetation has also accelerated the degradation process. The incised condition of the
existing channel is accelerating the erosion process by forcing the channel to contain
larger then bankfull storm events.
The restoration site is located entirely within the property boundaries of the Pine Valley
Country Club. A City of Wilmington 16" RCP sewer line is located along the entire
length of the reach that is being considered for restoration. The sewer line crosses the
existing channel twice within the reach and is offset from the existing channel by a range
of loft to 40ft. There are two power-lines and numerous irrigation lines for the golf
course within the project limits. The Middle Branch of Hewlett's Creek has many urban
constraints, but should be an excellent potential restoration site, and ideal for
demonstration and education.
Restoration requires determining how far the stream has departed from its natural
stability and then, establishing the stable form of the stream under the current hydrologic
conditions within the drainage area. The proposed restoration will construct a stable
meander geometry, modify channel cross-sections, and establish a floodplain at the
existing stream elevation, thus, restoring a stable dimension, pattern and profile. This
restoration is based on analysis of current watershed hydrologic conditions, evaluation of
the project site, and assessments of stable reference reaches. The following
recommendations are included in this restoration plan:
• Form a stable channel with the proper dimension, pattern and profile.
• Establish a floodplain along the stream channel.
• Place natural material structures in the stream to improve stability and enhance
aquatic habitat.
• Stabilize stream banks with herbaceous and woody vegetation
1
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
1.1 PROJECT DESCRIPTION
The Middle Branch of Hewlett's Creek project site is located in Hanover County, North
Carolina. The project is fully contained within the property of one landowner (The Pine
Valley Country Club). The project reach is bounded by The Long Street Drainage Cannel
to the west (upstream) and a 78" RCP culvert for Robert E. Lee Drive to the east
(downstream) (Figure 1).
1.2 GOALS AND OBJECTIVES
This project has the following goals and objectives:
1. Restore 3527 linear feet of The Middle Branch of Hewlett's Creek (as measured
along the centerline)
2. Provide a stable stream channel that neither aggrades nor degrades while maintaining
its dimension, pattern, and profile with the capacity to transport its watershed's water
and sediment load.
3. Improve water quality and reduce further property loss by stabilizing eroding stream
banks.
4. Establish a new floodplain at the existing stream elevation.
5. Improve aquatic habitat with the use of natural material stabilization structures such
as root wads; log vanes, woody debris and a riparian buffer.
6. Provide aesthetic value, wildlife habitat and bank stability through the creation or
enhancement of a riparian zone.
1.3 STREAM SURVEY METHODOLOGY
The US Forest Service General Technical Report RM-245, Stream Channel Reference
Sites: An Illustrated Guide to Field Technique is used as a guide when taking field
measurements. Accurate field measurements are critical to determine the present
condition of the existing channel, conditions of the floodplain, and watershed drainage
patterns.
2
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Site Area Boundary
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New Hanover County, NC" `
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Source: New Hanover County GIs Department i1CD[hR Dt??
FIGURE 1
' SITE LOCATION
RESTORATION PLAN
3
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
NCSU contracted with W. K. Dickson to conduct a topographic survey of the restoration
site in August 2002. This mapping along with field measurements taken by NCSU staff
was used to evaluate present conditions, new channel alignment and grading volumes.
Mapping also provided locations of property pins, large trees, vegetation lines, and
culverts, roads, utilities and elevation contours.
A windshield survey was also conducted to determine the existing conditions within the
watershed. The watershed is fully (>90%) developed with residential dwellings and has
an area of 1.5 sq. miles
During the site visits, three cross-sections were taken using standard differential leveling
techniques. These cross-sections were used to gather detail on the present dimension and
condition of the channel. Bankfull cross-sectional area was calculated using the bankfull
features, the bankfull area at riffles varied between 26 sqft to 31 sqft.
1.3.1 Stream Delineation Criteria - Classification
Dave Rosgen developed his stream classification system in order to accomplish the
following:
1) Predict a river's behavior
2) Develop specific hydraulic and sediment relationships for a given stream type and its
state
3) Provide a mechanism to extrapolate site-specific data to stream reaches having
similar characteristics
4) Provide a consistent frame of reference for communicating stream morphology and
condition among a variety of disciplines and interested parties
The Rosgen Stream Classification System is based on five criteria: width/depth ratio,
entrenchment ratio, slope, sinuosity, and channel materials. All cross-sections were
classified using this system.
1.3.2 Bankfull Verification
The foundation of Dave Rosgen's classification system is the concept of bankfull stage,
which is the point of incipient flooding. The width/depth and entrenchment ratios
described above depend on the correct assessment of bankfull. If bankfull is incorrectly
determined in the field, the entire restoration effort will be based on faulty data. It is
important to verify the physical indicators observed in the field with either gage data or a
regional curve to ensure the correct assessment of the bankfull stage.
The bankfull stage is determined in the field using physical indicators. The following is a
list of commonly used indicators that define bankfull (Rosgen, 1996):
4
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
• The presence of a floodplain at the elevation of incipient flooding.
• The elevation associated with the top of the highest depositional feature (e.g. point
bars, central bars within the active channel). These depositional features are
especially good stage indicators for channels in the presence of terrace or adjacent
colluvial slopes.
• A break in slope of the bank and/or a change in the particle size distribution, since
finer material is associated with deposition by overflow, rather than deposition of
coarser material within the active channel.
• Evidence of an inundation feature such as small benches below bankfull.
• Staining of rocks.
The most dominant bankfull indicators along The Middle Branch of Hewlett's Creek are
high scour lines and breaks in slope along the backs of narrow point bars.
The most common method of verifying bankfull stage is to compare the field determined
bankfull stage with measured stages at a stream gauging station. This calibration can be
performed if there is a stream gage within the study area's hydro-physiographic region.
In un-gauged areas, Dave Rosgen recommends verifying bankfull with the development
of regional curves. The regional curves normally plot bankfull discharge (QbkD, cross-
sectional area, width, and depth as a function of drainage area. The cross-sectional areas
of The Middle Branch of Hewlett's Creek was plotted on the Urban, Coastal Regional
Curve of North Carolina developed by the North Carolina State University (NCSU)
Water Quality Group, 2003 to help verify bankfull stage.
Data obtained from field surveys was used to compute the morphological characteristics
shown on the graph. The cross-sectional area for The Middle Branch of Hewlett's Creek
plots along the trend line for the Urban Regional Curve. The bankfull cross-sectional area
for the design channel was determined from evaluating the North Carolina regional curve
relationships and comparing them to the reference reach sites surveyed near the
restoration site. HEC-RAS was used to verify the design cross-sectional area for the
project.
5
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.0 EXISTING CONDITIONS
2.1 WATERSHED
2.1.1 General Description of the Watershed
The Middle Branch of the Hewlett Creek is a second order stream, is located within the
Coastal Physiographic Province of the Cape Fear River Basin (USGS Cataloging Unit).
The watershed is located in the Southeast corner of Wilmington, in New Hanover
County, North Carolina. The headwaters of the project originate approximately 2 miles to
the north-northeast of the restoration site. From the headwaters, Hewlett flows for
approximately 4.0 miles before emptying into the Greenville Sound just southwest of
Masonboro inlet. The land use within the study is mixed residential, commercial, and an
18-hole golf course.
The watershed is approximately 1.5 square miles (Figure 2). The watershed is oriented
north to south bending to the east before the project site. The topography ranges from
gently sloping to flat with relatively flat former floodplain that has be detached by
channeling the stream the middle of the past century. Land surface elevations range from
approximately 30 to 55 feet above mean sea level.
2.1.2 Surface Waters Classification
Surface waters in North Carolina are assigned a classification by the DWQ that is
designed to maintain, protect, and enhance water quality within the state. Hewlett's Creek
(NCDWQ Stream Index Number) is classified as a class SA HQW water body
(NCDENR, 2001). SA HQW water resources are waters protected for shellfish
propagation and survival, fishing, wildlife, secondary recreation, and agriculture.
2.1.3 Soils of the Watershed
The soils found in the watershed and adjacent to the stream can help determine the bed
and bank materials occurring in the stream. The Rosgen stream classification system uses
average particle size within the bankfull channel to help classify the stream. Knowing the
make up of the soils in the watershed, assists in understanding the anticipated bed-load
and sediment transport capacity of the stream.
Soils in upland areas within the watershed consist primarily of sand and urban complex
(draft maps and descriptions of the soils in the project area - New Hanover County Soil
Survey Office, Natural Resources Conservation Service [NRCS]). Depth to bedrock is
mapped as greater than 60 inches for the soils in the watershed. Soils in the side slopes
shoulders and summits of ridges include Baymeade-Urban Land complex 1 to 6 percent
slopes, and Rimini sand 1 to 6 percent slopes
6
The Middle Branch of Hewlett's Creek
New Hanover County, NC
The Middle Branch of Hewlett's Creek
New Hanover County, NC North
11 11.125 1125 0.5 1175
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FIGURE 2
WATERSHED ARIAL
RESTORATION PLAN
7
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.1.4 Land Use of the Watershed
Land use within the watershed is predominately urban residential (Figure 2). Evaluation
of a 1998 aerial photo obtained from New Hanover Country reveals that approximately
90% of the watershed is built out with single home residential areas, roads, businesses
and golf courses, with the remaining being water detention and forested urban land that is
not likely to be developed. The total percent impervious cover in the watershed is
approximately 20%-30%
2.2 RESTORATION SITE
The following sections provide a description of existing site conditions. This includes the
current stream conditions, soils, and surrounding plant communities.
2.2.1 Site Description
The Middle Branch of Hewlett's Creek restoration site begins approximately 4.0 miles
from its confluence with the Greenville Sound. The project is located within the property
boundaries of The Pine Valley Country Club. The middle Branch of Hewlett's Creek
flows from the west to east through a 0 to 35-foot wide floodplain. The majority of the
floodplain is located on the within the ditched channel of Hewlett's creek. The
floodplain typically ends abruptly at the toe of the adjoining steep slopes. A former
terrace extends along the entire length of the project and is 75 to 300 feet wide the
majority of the terrace is presently being used as fairway for the adjacent golf course.
The channel has long straight reaches with very minimal meanders. Channel sinuosity for
the entire reach is 1.05. High banks and areas of severe bank erosion can be found
throughout the project reach.
The main factor in the degradation and impairment for the Middle Branch of Hewlett's
Creek appears to be historic straightening of the channel and removal of riparian
vegetation. Straightening has increased the channel slope and decreased the stream
sinuosity. Erosion has caused increased sediment supply and channel widening. This has
combined to lead to the development of central bars in several straight sections of the
channel. Further development of central bars will increase erosion and lateral migration
of the channel.
2.2.2 Existing Stream Characteristics
Field surveys of the existing stream channel and site were conducted in August 2002.
The Middle Branch of Hewlett's Creek Restoration Site can be typically defined as a
predominantly straight channel with poor habitat. Stream banks are steep with areas of
active erosion. Long straight sections of the channel have central bars forming; indicating
the channel is over-wide. Instead of focusing the flow along the thalweg, the central bars
deflect the stream-flow toward the banks and accelerate bank erosion.
8
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
flow toward the banks and accelerate bank erosion.
Riffle bankfull widths for Beaver Creek range from 24 to 30 feet with mean depths
ranging from 1.2 to 1.5 feet. The cross-sectional areas for these riffles range from 26.0 to
31.5 square feet. All of the cross-sections were taken within the reach to be restored. All
cross-sections classed as type-F or G channels as the amount of incision increases
downstream. The stream has the following average characteristics:
Bankfull Width: 27 feet
Bankfull Cross-sectional Area: 30 square feet
Bankfull Mean Depth: 1.3 feet
Bankfull Maximum Depth: 4.1 feet
Average Water Surface Slope: 0.002 feet/feet
Entrenchment Ratio: >6.0
Sinuosity: <1.05
Bank Height Ratio 2.0
The entire length of channel within the restoration site was rated using the Bank Erosion
Hazard Index (BEHI). The most likely bank to erode was assessed throughout the reach.
The reach was subdivided into sections with similar erosional characteristics such as
surface protection, root depth, root density, and bank angle. Results are listed in Table 1.
The overall restoration reach has a BEHI rating of high, although two sections had a
BHEI rating of very high and extreme. It is likely these two areas will expand as erosion
continues. The main cause of the very high and extreme ratings are due to the lack of
significant deep rooting vegetation and surface protection. Restoration will reestablish
deep rooting vegetation along the banks throughout the entire reach.
2.2.3 Soils of the Restoration Site
According to the preliminary soil maps for New Hanover County, soils adjacent to the
Middle Branch of Creek within the restoration site are mapped as Rimini, Baymeade and
Lynn Haven soils (Figure 3). Investigation of the soils adjacent to the stream indicates
that all three soils are present, although Lynn Haven is the most common. Lynn Haven is
a fine sandy soil that is well drained. These permeable soils occur on nearly level
floodplains along creeks and rivers. The original wetland soils where most likely covered
and removed when the golf course was built up and the creek was straightened
Soil textures encountered include sand and fine sand. The seasonal high water table was
observed to be greater than 40 inches for most soils within the project. Slopes range from
0 to 6 percent.
2.2.4 Terrestrial Plant Communities
The following sections describe the existing plant communities on and adjacent to the
restoration site. For purposes of this project, three plant communities are described:
Managed Land, Bottomland Forest, and Upland Hardwood Forest. Nomenclature follows
Radford (1968).
9

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New Hanover County, NC
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New Hanover County, NC
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FIGURE 3
SOILS MAP
RESTORATION PLAN
II
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.2.4.1 Managed Land
Managed Land consisting of mowed and fertilized golf turf is present in the upland area
on the either side of the Middle Branch of Creek. The vegetation is herbaceous and
includes fescue grasses (Festuca sp.). Included within this community type is a cultivated
turf grasses owner by the Pine Valley Country Club. ) Other typical landscape plants
include: Crepe Myrtle (Lagerstroemia spp.), Wax myrtle (Myrica cerifera), Fountain
grass (Pennisetum alopecuroides), Liriope spp. and/or Ophiopogon spp.
2.2.4.2 Bottomland Forest
A Bottomland Forest community is present along the floodplain and stream banks. This a
mature forest with trees reaching 70 feet in height. The understory is relatively open
except where this community adjoins the disturbed areas. Trees in this community
include Water Oak (Quercus nigra), Maple (Acer spp.), Cherry (Prunus spp.), Ash
(Fraxinus spp.), Willow (Salix spp.) Wax myrtle (Myrica cerifera).
2.2.4.3 Upland Hardwood Forest
An Upland Hardwood Forest community covers most of the upland areas adjacent to the
project. This is a mature forest reaching 80 feet in height. The canopy trees in this
community include white oak (Quercus alba), tulip poplar, and magnolias. Prominent on
the north facing slopes is an understory dominated by rhododendron, forming a
continuous cover over large portions of the side slopes. On the south facing slopes the
canopy species include additional species such as Virginia pine (Pinus virgin Tana) and
various oaks. The understory lacks rhododendron and is not a dense as the north-facing
slope. Understory species include flowering dogwood and sourwood (Oxydendnem
arboreum).
2.2.4.4 Possible Invasive Flora
The following species were identified during site visits to the Middle Branch of Hewlett's
Creek; Japanese Honeysuckle (Lonicera japonica), Tree of Heaven (Ailanthus altissima),
Downy brome (Bromus tectonun), and Spotted Knapweed (Centaurea maculosa). These
species were identified by a brief visual inspection of the site; but could be mistaken for
similar species.
12
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.2.5 Wildlife Observations
Wildlife and signs of wildlife were noted during on-site visits, however, a formal wildlife
survey was not performed. Tracks of white tailed deer (Odocoileus virgin ianus) and
raccoon (Procyon Iotor) were observed along the stream banks. A variety of birds were
observed in the thickets and shrubs surrounding the stream channel and forest, including:
various sparrows.
2.2.5.1 Possible Invasive Wildlife
The following species were identified during site visits to the Middle Branch of Hewlett's
Creek; Asian tiger mosquito (Aedes albopictus), Bullfrog (Rana catesbeiana) (auditory
identification), European gypsy moth (Lymautria dispar), and European starling (Sturnus
vulgaris). The bullfrog is listed based on auditory identification by one of the project
researchers. The gypsy moth is listed based on visual identification of nests. The
mosquito and starling are listed due to their ubiquitous nature.
2.2.6 Endangered Species
The NCSU design team has not identified endangered plant or animal species or any such
habitat that would support the endangered species listed in this section. The NCSU
design team has made multiple visits to the Pine Valley Country Club and the restoration
site. Below is a list obtained from Natural Heritage, of the endangered of concern for
New Hanover County.
2.2.6.1 Endangered Flora
Vascular Plants:
Cooley's meadowrue Endangered
Rough-leaved loosestrife Endangered
Seabeach amaranth Threatened
Bog St. John's-wort Federal Species of Concern
Carolina asphodel Federal Species of Concern
Carolina bishopweed Federal Species of Concern
Carolina beaksedge Federal Species of Concern
Chapman's sedge Federal Species of Concern
Coastal golden rod Federal Species of Concern
"Dune bluecurls" Federal Species of Concern
Pickering's dawnflower Federal Species of Concern
Pondspice Federal Species of Concern
Sandhills milkvetch Federal Species of Concern
Savanna indigo-bush Federal Species of Concern
Spiked medusa Federal Species of Concern
Spring-flowering goldenrod Federal Species of Concern
Tough bumelia Federal Species of Concern
13
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Venus flytrap Federal Species of Concern
2.2.6.2 Endangered Fauna
Vertebrates:
Red-cockaded woodpecker Endangered
Shortnose sturgeon Endangered
West Indian Manatee Endangered
American Alligator Threatened
Green sea turtle Threatened
Loggerhead sea turtle Threatened
Piping Plover Threatened
Carolina gopher frog Federal Species of Concern
Eastern painted bunting Federal Species of Concern
Mimic glass lizard Federal Species of Concern
Northern pine snake Federal Species of Concern
Southeastern myotis Federal Species of Concern
Southern Hognose snake Federal Species of Concern
Invertebrates:
Arogos skipper
Buchholz's dart mouth
Cape Fear threetooth
Croatan crayfish
Magnificent rams-horn
Rare skipper
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
14
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
3.0 REFERENCE REACHES
Reference reaches were utilized on which the morphological characteristics were
measured to determine a range of values for the stable dimension, pattern, and profile of
the proposed channel. The following sections include a detail of three of the reference
reaches that were used for design of the restoration plan for the Middle Branch of
Hewlett's Creek. The reference reaches used along with the bankfull area, and current
constraints as the base for the preliminary design.
3.1 JOHANNAH CREEK
The Johannah creek has a drainage area of 1.18 square miles. Angela Moreland of the
NCSU Water Quality group completed the stream survey of Johannah creek in the
summer of 2001. The stream had a bankfull channel width of 10.4 feet and a bankfull
mean depth of 0.8 feet. Johannah Creek is a C5 stream type from Rosgen Classification
system. The morphological characteristics of this reference stream are included in Table
2.
3.2 PANTHER BRANCH
The Panther branch has a drainage area of 1.69 square miles. Angela Moreland of the
NCSU Water Quality group completed the stream survey of Panther branch in the
summer of 2001. The stream had a bankfull channel width of 11.5 feet and a bankfull
mean depth of 1.6 feet. Panther Branch is an E5 stream type from Rosgen Classification
system. The morphological characteristics of this reference stream are included in Table
2.
3.3 BATORORA BRANCH
Angela Moreland of the NCSU Water Quality group completed the stream survey of
Batorora branch in the summer of 2001. The stream had a bankfull channel width of 15.5
feet and a bankfull mean depth of 1.5 feet. Batorora Branch is an E5 stream type from
Rosgen Classification system. The morphological characteristics of this reference stream
are included in Table 2.
P
C
15
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
. New Hanover County, NC
Table 2. Middle Branch of Hewlett's Creek Morphology (Existing,
Design, and Reference) 7U
Parameter Existing Referen Reference Reference Design
Reach Name Hewlett Panther Johannah Batorora Hewlett
Bankfull XSEC Area, Abkf (ft) 30 7.9 8.6 23.9 30
Bankfull Width, Wbkf (ft) 20 11.5 10.4 15.5 19
Bankfull Mean Depth, Dbkf (ft) 1.5 1.6 0.8 1.5 1.6
Width to Depth Ratio, W/D (ft/ft) /-12.3 7.4 12.6 10.1 12,
Entrenchment Ratio, Wfpa/Wbkf (ft/ft) 2 17.4 19.2 12.9 3
Bank Height Ratio, Dtob/Dmax (ft/ft) 2. 1 1 1
Min Bkf Max Depth, Dmax (ft) 1.6 --- --- --- 2.1
Max Bkf Max Depth, Dmax (ft) 1.9 --- --- --- 2.8
Min Bkf Max Depth, Dmax/Dbkf 1.1 1.6 1.3 1.4 1.3
Max Bkf Max Depth, Dmax/Dbkf 1.3 1.8
Min Meander Length, Lm (ft) 100 --- --- - 86
Max Meander Length, Lm (ft) 280 --- --- --- 171
Min Meander Ion Ratio, Im/Wbkf 5 2.3 1.9 4.1 4.5
Max Meander Len Ratio, Lm/Wbkf 14 9.1 5.1 6.8 9
Min Radius of Curvature, Rc (ft) 60 --- --- --- 34
Max Radius of Curvature, Rc (ft) 80 --- ... --- 49
Min Rc Ratio, Rc/Wbkf 3 0.5 0.9 0.7 1.8
Max Rc Ratio, Rc/Wbkf 4 1.5 2.3 2.6 2.6
Min Belt Width, Wblt (ft) 25 --- --- -- 42
Max Belt Width, Wblt (ft) 40 --- --- --- 76
Min MW Ratio, Wblt/Wbkf (ft) 1.3 1.9 1.3 2.9 2.2
Max MW Ratio, Wblt/Wbkf (ft) 2 8.7 4.4 4.5 ?--14
Sinuosity, K 1.05 1.2 1.2 1.2 1.2
Valley Slope, Sval (ft/ft) .0026 .0040 .0026 .0061
Channel Slope, Schan=SvaUK (ft/ft) .0025 .0033 .0021 .0051 .0021
Pool Slope, Spool (ft/ft) 0 --- --- --- f0
Pool Slope Ratio, Spool/Schan 0 0 0 0
Min Pool Depth, Dpool (ft) 1.7 --- -- - 2.4
Max Pool Depth, Dpool (ft) 2 --- --- --- 3.0
Min Pool Depth Ratio, Dpool/Dbkf 1.1 1.6 1.9 2 1.5
Max Pool Depth Ratio, Dpool/Dbkf 1.3 2
Min Pool Width, Wpool (ft) 21 --- --- --- 19
Max Pool Width, Wpool (ft) 25 --- --- --- 22.8
Min Pool Wid Ratio, Wpool/Wbkf 1.1 1 1.2 0.9 1
Max Pool Wid Ratio, Wpool/Wbkf 1.3 1.2
Min Length Pool Spacing, Lps (ft) 40 --- --- --- 57
Max Length Pool Spacing, Lps (ft) 220 --- --- --- 114
Min Pool Spacing Ratio, Lps/Wbkf 2 1.3 1.2 1.7 3
Max Pool Spacing Ratio, Lps/Wbkf 11 5.7 3.8 3.9 6
A
ti

16
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.0 STREAM CHANNEL DESIGN
This restoration will classify as Priority 2 storation (Rosgen, 1997). The floodplain
will be re-established to fit the ex" i r slightly raised stream profile. The grade of the
stream will be raised in some areas and a floodplain will be established at the new
bankfull elevation. Table 3 describes and summarizes the four priorities of incised river
restoration (Rosgen, 1997). The proposed stream restoration will restore the natural
meander pattern, modify channel cross-section restore bedform, improve sediment
transport capacity, enhance habitat, and re-establish a floodplain for the stream.
The design was based upon Dave Rosgen's natural channel design methodology. As
described in Section 3.0, reference reaches were utilized on which the morphological
characteristics were measured to determine a range of values for the stable dimension,
pattern, and profile of the proposed channel. The measured and proposed morphological
characteristics are shown in Table 2.
A conceptual design was developed from the range of values listed in Table 2. This
stream restoration project will result in approximately 3,600 restored linear feet (as
measure from the thalweg) of The Middle Branch of Hewlett's Creek. The plan view of
the proposed restoration design can be seen in Figures 4, 5 and 6.
17
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Table 3. Priorities, Description and Summary for Incised River Restoration
DESCRIPTION METHODS ADVANTAGES DISADVANTAGES
PRIORITY 1 Re-establish channel on Re-establishment of 1) floodplain re-
Convert G and/or F previous floodplain using relic floodplain and stable establishment could cause
stream types to C and/or channel or construction of channel: flood damage to urban
E at previous elevation new bankfull discharge 1) reduces bank height and agricultural and industrial
w/floodplain channel. Design new channel streambank erosion development.
for dimension, pattern and 2) reduces land loss 2) downstream end of
profile characteristic of stable 3) raises water table project could require grade
form. Fill in existing incised 4) decreases sediment control from new to
channel or with discontinuous 5) improves aquatic and previous channel to prevent
oxbow lakes level with new terrestrial habitats head-cutting.
floodplain elevation. 6) improves land
productivity, and
7) improves aesthetics.
PRIORITY 2 If belt width provides for the 1) decreases bank height 1) does not raise water
Convert G and/or F minimum meander width ratio and streambank erosion table back to previous
stream types to C or E. for C or E stream types, 2) allows for riparian elevation
Re-establishment of construct channel in bed of vegetation to help stabilize 2) shear stress and velocity
floodplain at existing or existing channel, convert banks higher during flood due to
higher, but not at existing bed to new 3) establishes floodplain to narrower floodplain
original level floodplain. If belt width is too help take stress of channel 3) upper banks need to be
narrow, excavate streambank during flood sloped and stabilized to
walls. End-hall material or 4) improves aquatic habitat reduce erosion during
place in streambed to raise 5) prevents wide-scale flood.
bed elevation and create new flooding of original land
floodplain in the deposition. surface
6) reduces sediment
7) downstream grade
transition for grade control
is easier.
PRIORITY 3 Excavation of channel to 1) reduces the amount of 1) high cost of materials
Convert to a new stream change stream type involves land needed to return the for bed and streambank
type without an active establishing proper river to a stable form. stabilization
floodplain, but dimension, pattern and 2) developments next to 2) does not create the
containing a floodprone profile. To convert G to B river need not be re-located diversity of aquatic habitat
area. Convert G to B stream involves an increase in due to flooding potential 3) does not raise water
stream type, or F to Be width/depth and entrenchment 3) decreases flood stage for table to previous levels.
ratio, shaping upper slopes the same magnitude flood
and stabilizing both bed and 4) improves aquatic
banks. A conversion from F habitat.
to Be stream type involves a
decrease in width/depth ratio
and an increase in
entrenchment ratio.
PRIORITY 4 A long list of stabilization 1) excavation volumes 1) high cost for
Stabilize channel in materials and methods have reduced stabilization
place been used to decrease stream 2) land needed for 2) high risk due to
bed and bank erosion, restoration is minimal excessive shear stress and
including concrete, gabions, velocity
boulders and bio-engineering 3) limited aquatic habitat
methods depending on nature of
stabilization methods used.
Source: Rosgen, 1997, "A Geomorphological Approach to Restoration of Incised Rivers"
18
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Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.1 RESTORATION TECHNIQUES
Stream dimension, pattern, and profile will be adjusted so the new stream channel can
maintain stability while transporting its water and sediment load. The Priority 2
restoration (see Table 3) will involve modifying the existing channel at its existing
elevation to create a stable channel.
Vegetation will be utilized to provide stability and improve habitat along the stream
banks and riparian areas. The greatest advantage of this Priority 2 restoration will be to
create a floodplain that the active channel can access. Other advantages of a Priority 2
restoration include improving aesthetics, improving habitat, reduction of bank height and
streambank erosion, and lowering of the in-channel shear stress.
4.1.1 Dimension
The present bankfull channel width ranges from 24 to 30 square feet, with a cross-
sectional area ranging from 26.0 to 31.5 square feet. The design channel will be
constructed to bankfull target dimensions that are based on a combination of reference
reach surveys, existing conditions survey, and regional curve information. Typical cross-
sections can be seen in Figure 7.
A design width of 19 feet will be applied to the proposed reach. This width was back-
calculated from the cross-sectional area taken from the existing survey, reference reach
surveys, and a width-to-depth ratio of 12.0. Required mean depth of the channel was
verified using shear stress relationships to ensure there is enough design depth to
transport the channel bedload without aggrading or degrading. These characteristics will
provide a stream channel that classifies as an E-type channel according to the Rosgen
classification system.
The existing channel, with bank height ratio's ranging from 1.6 to 2.4, will have benches
cut at the bankfull elevation. This bankfull bench will establish a floodplain at the
bankfull elevation of the existing channel thus lowering the bank height ratio also.
Channel width will be addressed by using vanes to turn and deflect flow. Grading banks
to fit typical design cross-sections can modify the bankfull dimensions. The proposed
channel will be able to access a floodplain and effectively transport the sediment load.
4.1.2 Pattern
The existing pattern of the Middle Branch of Hewlett's Creek can be described as long
straight reaches. The current sinuosity within the project boundaries is less than 1.05.
This is common on channels that have been previously straightening. The stream will
continue to try and meander until a stable planform is established. Active erosion will
continue while the stream tries to reach a stable planform but is limited by urban
constraints within the project limits.
22
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Existing pattern measurements were taken from the topographic mapping. A stable
pattern will be established by establishing new meanders along the channel. This will be
achieved by introducing meanders into the stream with radius of curvatures and lengths
based on reference reach data and the existing constraints. The maximum stream length
and sinuosity has been designed into the new channel based on the reference data and
project constraints. Introduction of these meanders will improve habitat while lowering
slope and shear stress.
4.1.3 Bedform
The existing bedform along the Middle Branch of Hewlett's Creek is in poor condition.
Long, straight sections of the channel consist of predominantly run bedform features. The
design channel will incorporate, ripples,,.and pools to provide bedform common to E5
stream types. Pools will be located in the outside of meander bends with riffles in the
inflection points between meanders. The ripples will have a thalweg depth of 1.6 feet
while the pools will be deeper with a maximum depth of 3.0 feet. A graph of the
proposed profile can be seen in Figure 8. The profile may be adjusted slightly during the
final design phase of the project.
Cross-vanes will be utilized as grade control structures and to tie the relocated sections
back into the e 'channel. The cross vanes will be constructed out of natural
materials such s 7?. d some bouldegers. nn nn 1 r? ?', (?w??-Ss
The existing pool-to-pool spacing is impaired in areas due to tight meander geometry.
The proposed spacing is 57 to 114 feet, which is within the range of 3 and 6 bankfull
widths as determined from the reference reach data. To accomplish this, pools will be ?J\ t`
realigned or constructed such that they will be located in the outside of the meander
bends. Bedform will also be addressed through trategic-place?nt of natural material `t
structures such as cross vanes, root wads a%th woody deb ' .Modifications to the
bedform will provide stability and habitat to ann?f
4.1.4 Riparian Areas
?, A riparian zone will be created around the new proposed stream channel to enhance both
aquatic and terrestri bjtat as well as stabilize the stream channel. The riparian zone
i extend at leas 15 feet )on either side of annel from the top of bank. Were ever
possible the riparian ne will extend at lea t 25 f et on either side of the channel. These
areas will be planted with appropri ate riparian vegetation as described in Section 6.0
Habitat Restoration. The riparian zone is limited by the urban constraints and the
constraints of an active golf course that includes play that cross the stream channel.
23
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Figure 7: Typical Cross-Sections
Typical X-Section Riffle
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Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.2 SEDIMENT TRANSPORT
A stable stream has the capacity to move its sediment load without aggrading or
degrading. The total load of sediment can be divided into bed load and wash load. Wash
load is normally composed of fine sands, silts and clay and transported in suspension at a
rate that is determined by availability and not hydraulically controlled. Bed load is
transported by rolling, sliding, or hopping (saltating) along the bed. At higher discharges,
some portion of the bed load can be suspended, especially if there is a sand component in
the bed load. Bed material transport rates are essentially controlled by the size and nature
of the bed material and hydraulic conditions (Hey 1997).
Critical dimensionless shear stress can be found using Shields_Curvnd surface article
f sample from a representative riffle in the reach. A riffle bed surface pebble count as 6ti
taken at a riffle on the Middle Branch of Hewlett 's Cree c-Tnff e e surface d50 was 5
then calculated to be 0.06 mm. The shear stress placed on the sediment particles is the
force that entrains and moves the particles, in a given channel geometry. From Shields 11 (;nN'
X curve the shear stress that entrains and moves particles in this stream based on the d50 is
.0025 lbs/sgft.
Wetted perimeter was measured off of a CADD file of the typical riffle cross-section
drawn to scale. The wetted perimeter was measured to be 29 ft, while the cross-sectional
area was 30 sgft this produced a hydraulic radius of 1.03. The Slope for the used for the
shear stress calculation is 0.0023. The resultant shear stress for the proposed channel is
0.15 lbs/sgft, this shear stress is sufficient to move the d84 of the riffle bed material,
which is 0.15 mm. Shield's Curve predicts that this stream can move a particle that is, o
average, greater than 5 mm. Since the D84 was 0.15 mm and Shield's Curve predi s 5
mm, the proposed stream has the competency to move its bed load.
Sediment transport analysis was examined at the restoration site through the comparison
of existing and post restoration shear stress analysis. The existing channel does not
appear to be aggrading so it is implied that it is more capable of transporting its
watershed sediment load. Two existing shear stresses are examined and one restored
shear stress. Shear stress is approximated using the equation shear stress = density of
water times the hydraulic radius times the average water surface slope. Existing bankfull S
shear stress is 0.233 lbs/sgft. The top of bank shear stress is 0.454 lbs/sqft.
t, r
Post restoration, average water surface slope will be decreased and the floodplain will be
established adjacent to the bankfull channel thus lowering the top of bank shear stress
significantly. The post restoration bankfull shear and top of bank shear stress is 0.222 h
lbs/sgft. These calculations were confirmed with HEC-RAS modeling.
4.3 FLOODING ANALYSIS
This restoration site is not in a mapped FEMA regulatory floodway zone and therefore, is x k??
not subject to FEMA regulations. NCSU design team has also received verification from
26 ; .
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
the City of Wilmington Division of Stormwater that this reach of Hewlett's Creek is not
FEMA mapped and does not have a recorded history of flood related incidents. Currently
there are no structures located in the adjacent areas that would be impacted by floodplain
alterations. The Priority 2 restoration of the stream will leave the stream's existing profile
elevations essentially the same. A new floodplain will be established so that the active
stream will be able to access it during larger storm events. Considering the type of
restoration it is assumed that for smaller events the water surface elevations along the
stream shall remain the same. During storms where the stream accesses the newly
establishment floodplain the new water surface elevations are expected to be lower than
the existing water surface elevations of storms of the same magnitude. The restoration
will create neither positive nor negative water surface elevation changes during the larger
storm events (greater than 25-year). HEC-RAS was used to analyze both existing and
proposed conditions after the design was finalized. Sheer stress and flood stages were
compared at various return intervals to evaluate the design.
4.4 STRUCTURES
Several different structures made of natural materials will be installed along the Middle
Branch of Hewlett's Creek. These structures include cross vanes, single vanes, and root
wads. Natural materials such rocks and root wads will be used to create these structures
from off-site sources and on-site sources.
4.4.1 Cross Vane
A cross vane structure serves to maintain the grade of the stream. The design shape is ?
roughly that of the letter "U" with the apex located on the upstream side at the foot of the
riffle. Footer rocks are placed in the channel bottom for stability. Rocks or logs are then
placed on these footer rocks in the middle of the channel at approximately the same
elevation as the ripple. On either side of the channel, rocks or logs are placed at an angle
to the stream bank, gradually inclining in elevation until they are located above the
bankfull surface directly adjacent to the stream bank. Water flowing downstream is
directed over the vane towards the middle of the channel. Rocks or a log placed at the
apex determine the bed elevation upstream. A cross vane is primarily used for grade
control and to protect the stream banks.
v
4.4.2 Root Wads
The objectives of these structure placements are as follows: O 1 Protect the stream bank'
from erosion; (2) provide in-stream and overhead cover for fish; (3) provide shade,
detritus, terrestrial insect habitat: (4) look natural, and (5) provide diversity of habitats
(Rosgen 1996). A footer log and boulder are placed on the channel bottom abutting the
stream bank along an outside meander that will provide support for the root wad and
additional stability to the bank. A large tree root wad is then placed on the stream bank
with additional boulders and rocks on either side for stability. Flowing water is deflected
away from the bank and towards the center of the channel.
27
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.4.3 Single Vane
A single vane structure serves to maintain the pattern of the stream. Footer rocks are
placed in the channel bottom for stability. Rocks or logs are then placed on these footer '
rocks in the middle of the channel at approximately the same elevation as the ripple. On
either side of the channel, rocks or log is placed at an angle to the stream bank, gradually
inclining in elevation until they are located above the bankfull surface directly adjacent to
the stream bank. Water flowing downstream is directed over the vane towards the middle
of the channel. A single vane is primarily used to turn the stream flow and control and to
protect the stream banks.
Specific location of these structures will be determined during final design.
28
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
5.0 HABITAT RESTORATION
The restoration plan requires the establishment of riparian vegetation at the site. The
proposed vegetation is described in the following sections.
5.1 VEGETATION
Vegetation that develops a quick canopy, has an extensive root system, and a substantial
above-ground plant structure is needed to help stabilize the banks of a restored stream
channel in order to reduce scour and runoff erosion. In natural riparian environments,
pioneer plants that often provide these functions are alder, river birch, silky dogwood,
and willow. Once established, these trees and shrubs create an environment that allows
for the succession of the other riparian species including ashes, black walnuts, red
maples, sycamores, oaks, and other riparian species.
In the newly restored stream channel, revegetation will be vital to help stabilize the
stream banks and establish a riparian zone around the restored channel. Revegetation
efforts on this project will emulate natural vegetation communities found along relatively
undisturbed stream corridors. To quickly establish dense root mass along the channel
bank, a native grass mixture will be planted on the streambed and bank. Shrubs will be
utilized on the stream bank and along the floodplain to provide additional root mass.
Extra care will be given to the outside of the meander bends to ensure a dense root mass
in those areas of high stress. Coir matting or similar material will be used to provide
erosion protection until vegetation can be established. Along the tops of the channel
banks, trees, shrubs and a native grass mixture will be planted.
A mixture of seeds, live stakes, bare root, as well as balled in burlap nursery stock, some
2 "- 4" caliper tree and transplants will be used to stabilize the banks. Proposed species
to be planted included, but are not limited to:
Trees
Blackcherry (Prunus serotina)
Blackgum (Nyssa sylvatica)
Loblolly Bay (Gordonia lasianthus)
River Birch (Betula nigra)
Sugarberry (Celtis laevigata)
Shrubs
American hornbeam (Carpinus caroliniana)
Fetter bush (Lyonia lucida)
Inkberry (Ilex glabra)
Marsh mallow (Hibiscus n:oscheutos)
Silky dogwood (Conius amonnunn)
Sweet pepperbush (Clethra abuffolia)
Virginia willow (Itea virginica)
W? mltl?
29
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Herbs- Permanent seed mixture
Deertongue (Panicum clandestinum)
Purple love grass (Ergrostis spectabilis)
Switch Grass (Panicum virgatum)
Tussock sedge (Carex stricta)
Other herbaceous vegetation
Dwarf spike-rush (Eleocharis parvula)
Ironweed (Ventonia noveboracensis)
Jack-in-the-pulpit (Arisaetna triphylluni)
Woody vegetation will be planted between February and May to allow plants to stabilize
during the dormant period and set root during the spring season. In the areas where
invasive and exotic species are located, during construction and monitoring control by
removal or appropriate herbicides will be implemented to prevent competition with the
revegetation efforts.
5.2 RIPARIAN BUFFERS
At least three different types of riparian buffers will be employed to vegetate the restored
channel. All buffers will use plants native to the coastal plain region of North Carolina.
In areas where the fairways cross the stream channel, vegetation will be kept to a minimal
height so as not to obstruct views and play within the crossing. The areas along the city
sewer line (within approximately 10' to either side of the utility) will be planted with
vegetation having shallow (limited) root structure so that the sewer line and access to it
shall not be impacted or impeded. The remaining areas will be planted with native trees,
shrubs, grasses and other herbaceous vegetation in order to restore natural coastal plain
plant communities. Proposed species to be planted include but are not limited to those
listed in the above section
5.2.1 Temporary Seeding
A temporary seed mixture will be applied to all disturbed areas immediately after
construction activities have completed. This temporary seed mixture will provide erosion
control until permanent seed can become established. Permanent seed will be native to
the coastal region of North Carolina.
30
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
6.0 MONITORING
6.1 STREAM CHANNEL
Monitoring of the stability of the channel is recommended to occur approximately 6
months after restoration is complete or after bankfull (or greater) events and should
continue annually for a period of 3 to 5 years. Monitoring practices may include, but are
not limited to, installing bank erosion pins.and a toe pin, monumented cross-sections,
scour chains, macroinvertebrate studies, longitudinal profiles, conducting the bank
erosion hazard rating guide and establishing photo reference points. The purpose of
monitoring is to determine bank stability, bed stability, morphological stability and
overall channel stability. Table 4, below, can be used for selecting practices.
Table 3. Stream Monitoring Practices
PRACTICE STABILITY ASSESSMENT
Bank Erosion Pins with Toe Pin -Lateral or bank stability
Monumented Cross-Section -Vertical or bank stability
-Lateral or bank stability
Scour Chains -Vertical or bed stability
-Scour depth fora articular storm
Scour Chain w/ Monumented
Cross-Section -Vertical or bed stability
-Sediment transport relations
-Biological interpretations
Longitudinal Profile -Channel profile stability
Bank Erosion Hazard Guide -Bank erosion potential
Photo Reference Points -Overall channel stability
Macroinvertebrate -Biological indication of water quality
6.2 VEGETATION
Prior to planting, the site will be inspected and checked for proper elevation and
suitability of soils. Availability of acceptable, good quality plant species will be
determined. The site will be inspected at completion of planting to determine proper
planting methods, including proper plant spacing, density, and species composition.
Competition control will be implemented if determined to be necessary during the early
stages of growth and development of the tree species. Quantitative sampling of the
vegetation will be performed between August 1 and November 30 at the end of the first
year and after each growing season until the vegetation criteria is met.
In preparation for the quantitative sampling, 50 by 50 feet (0.05-acre) vegetative plots
will be established in the reforested area. Plots will be evenly distributed throughout the
31
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
site. For each plot, species composition and density will be reported. Photo points will be
taken within each zone. Monitoring will take place once each year for five years.
Success will be determined by survival of target species within the sample plots. At least
six different representative tree species should be present on the entire site. If the
vegetative success criteria are not met, the cause of failure will be determined and
appropriate corrective action will be taken.
6.3 MACROIN VERTEBRATES
A monitoring period of 3 to S years is commonly suggested to determine changes in
macroinvertebrate populations within a newly restored stream. The North Carolina
Wetlands Restoration Program will determine a macroinvertebrate monitoring policy.

32

Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
7.0 REFERENCES
Amoroso, J.L., ed. 1999. Natural Heritage Program List of the Rare Plant Species of
North Carolina. North Carolina Natural Heritage Program, Division of Parks and
Recreation, North Carolina Department of Environment and Natural Resources. Raleigh,
North Carolina.
Cowardin, L.M., V. Carter, F.C. Golet and E.T. LaRoe. 1979. Classification of Wetlands and
Deepwater Habitats of the United States. U.S. Fish and Wildlife Service, Office of
Biological Services, FWS/OBS-79/3 I. U.S. Department of the Interior, Washington, DC.
Choate, J.R., J,K. Jones, Jr., and C. Jones. 1994. Handbook of Mammals of the South-Central
States. Louisiana State University Press, Baton Rouge, Louisiana.
Doll, B. A., et al. 2000. Hydraulic Geometry Relationships for Urban Streams throughout the
Piedmont of North Carolina. American Water Resources Association.
Godfrey, R.K., and J.W. Wooten. 1979. Aquatic and Wetland Plants of Southeastern United States.
Monocotyledons. The University of Georgia Press, Athens, Georgia.
Godfrey, R.K., and J.W. Wooten. 1981. Aquatic and Wetland Plants of Southeastern United States.
Dicotyledons. The University of Georgia Press, Athens, Georgia.
Harrelson, Cheryl, C.L. Rawlins and John Potyondy. 1994. Stream Channel Reference Sites: An
Illustrated Guide to Field Technique. United States Department of Agriculture, Forest Service.
General Technical Report RM-245.
Hey, Richard and Dave Rosgen. 1997. Fluvial Geomorphology for Engineers. Wildland Hydrology,
Pagosa Springs, Colorado.
LeGrand, H.E., Jr. and S.P. Hall, eds. 1999. Natural Heritage Program List of the Rare
Animal Species of North Carolina. North Carolina Natural Heritage Program, Division of
Parks and Recreation, North Carolina Department of Environment and Natural
Resources. Raleigh, North Carolina.
NCDENR. "Water Quality Stream Classifications for Streams in North Carolina." Water Quality
Section. http:/Ih2o.enr.state.nc.us/wqhome.html (16 July 2001).
Radford, A.E., H.E. Ahles and G.R. Bell. 1968. Manual of the Vascular Flora of the Carolinas. The
University of North Carolina Press, Chapel Hill, North Carolina.
Rosgen, Dave. 1997. A Geomorphological Approach to Restoration of Incised Rivers.
Wildland Hydrology. Proceedings of the Conference on Management of Landscapes
Disturbed by Channel Incision.
33
a - A
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Schafale, M. P. and A. S. Weakley. 1990. Classification of the Natural Communities of
North Carolina: Third Approximation. North Carolina Natural Heritage Program.
Raleigh, North Carolina
United States Department of Agriculture - Soil Conservation Service. December, 1977. "Soil
Survey of Guilford County, North Carolina." US Government Printing Office, Washington,
DC.
United States Fish and Wildlife Service. "Region 4, Southeast Region/Endangered Species." North
Carolina Ecological Services. http://nc-es.fws.gov/ (August 2001).
USDA, NRCS. 2001. The PLANTS Database, Version 3.1 (http://plants.usda.gov). National Plant
Data Center, Baton Rouge, LA 70874-4490 USA.
34

11. List the type of equipment to be used to construct the project: Track Hoes, loaders
t2. Describe the land use in the vicinity of this project: Recreation-Golf
IV. Prior Project History
If jurisdictional determinations and/or permits have been requested and/or obtained for this
project (including all prior phases of the same subdivision) in the past, please explain. Include
the USACE Action ID Number, DWQ Project Number, application date, and date permits and
certifications were issued or withdrawn. Provide photocopies of previously issued permits,
certifications or other useful information. Describe previously approved wetland, stream and
buffer impacts, along with associated mitigation (where applicable). If this is a NCDOT project,
list and describe permits issued for prior segments of the same T.I.P. project, along with
construction schedules.
V. Future Project Plans
Are any future permit requests anticipated for this project'? If so, describe the anticipated work,
and provide justification for the exclusion of this work from the current application:
VI. Proposed Impacts to Waters of the United States/Waters of the State
It is the applicant's (or agent's) responsibility to determine, delineate and map all impacts to
wetlands, open water, and stream channels associated with the project. The applicant must also
provide justification for these impacts in Section VII below. All proposed impacts, permanent
and temporary, must be listed herein, and must be clearly identifiable on an accompanying site
plan. All wetlands and waters, and all streams (intermittent and perennial) must be shown on a
delineation map, whether or not impacts are proposed to these systems. Wetland and stream
evaluation and delineation forms should be included as appropriate. Photographs may be
included at the applicant's discretion. If this proposed impact is strictly for wetland or stream
mitigation, list and describe the impact in Section VIII below. If additional space is needed for
listing or description, please attach a separate sheet.
1. Wetland Impacts
Page 7 of 12
op?
Wetland Impact
Site Number
(indicate on ma)
Type of Impact* Area of
Impact
(acres) Located within
100-year Floodplain**
(es/no) Distance to
Nearest Stream
(linear feet)
Type of Wetland***

* List each impact separately and identify temporary impacts. Impacts include, but are not limited to: mechanized clearing, grading, fill,
excavation, flooding, ditching/drainage, etc. For dams, separately list impacts due to both structure and flooding.
** 100-Year floodplains are identified through the Federal Emergency Management Agency's (FEMA) Flood Insurance Rate Maps
(FIRM), or FEMA-approved local floodplain maps. Maps are available through the FEMA Map Service Center at 1-800-358-9616, or
online at httn://www.fema.gov.
*** List a wetland type that best describes wetland to be impacted (e.g., freshwater/saltwater marsh, forested wetland, beaver pond,
Carolina Bay, bog, etc.)
List the total acreage (estimated) of existing wetlands on the property: 1 ac
Total area of wetland impact proposed: 0
2. Stream Impacts, including all intermittent and perennial streams (SEE PLANS)
Stream Impact
Site Number
(indicate on ma)
Type of Impact* Length of
Impact
(linear feet)
Stream Name** Average Width
of Stream
Before Impact Perennial or
Intermittent'?
specify)

* List each impact separately and identify temporary impacts. Impacts include, but are not limited to: culverts and associated rip-rap,
dams (separately list impacts due to both structure and flooding), relocation (include linear feet before and after, and net loss/gain),
stabilization activities (cement wall, rip-rap, crib wall, gabions, etc.), excavation, ditching/straightening, etc. If stream relocation is
proposed, plans and profiles showing the linear footprint for both the original and relocated streams must be included.
** Stream names can be found on USGS topographic maps. If a stream has no name, list as UT (unnamed tributary) to the nearest
downstream named stream into which it flows. USGS maps are available through the USGS at 1-800-358-9616, or online at
www.usgs.gov. Several intemet sites also allow direct download and printing of USGS maps (e.g., www.topoozone.com,
www.maoguest.com, etc.).
Cumulative impacts (linear distance in feet) to all streams on site: 3527 FT
Page 8 of 12
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Existing pattern measurements were taken from the topographic mapping. A stable
pattern will be established by establishing new meanders along the channel. This will be
achieved by introducing meanders into the stream with radius of curvatures and lengths
based on reference reach data and the existing constraints. The maximum stream length
and sinuosity has been designed into the new channel based on the reference data and
project constraints. Introduction of these meanders will improve habitat while lowering
slope and shear stress.
4.1.3 Bedform
The existing bedform along the Middle Branch of Hewlett's Creek is in poor condition.
Long, straight sections of the channel consist of predominantly run bedform features. The
design channel will incorporate ripples and pools to provide bedform common to E5
stream types. Pools will be located in the outside of meander bends with riffles in the
inflection points between meanders. The ripples will have a thalweg depth of 1.6 feet
while the pools will be deeper with a maximum depth of 3.0 feet. A graph of the
proposed profile can be seen in Figure 8. The profile may be adjusted slightly during the
final design phase of the project.
Cross-vanes will be utilized as grade control structures and to tie the relocated sections
back into the existing channel. The cross vanes will be constructed out of natural
materials such as wood and some boulders.
The existing pool-to-pool spacing is impaired in areas due to tight meander geometry.
The proposed spacing is 57 to 114 feet, which is within the range of 3 and 6 bankfull
widths as determined from the reference reach data. To accomplish this, pools will be
realigned or constructed such that they will be located in the outside of the meander
bends. Bedform will also be addressed through the strategic placement of natural material
structures such as cross vanes, root wads and large woody debris. Modifications to the
bedform will provide stability and habitat to the channel.
4.1.4 Riparian Areas
A riparian zone will be created around the new proposed stream channel to enhance both
aquatic and terrestrial habitat as well as stabilize the stream channel. The riparian zone
will extend at least 15 feet on either side of the channel from the top of bank. Were ever
possible the riparian zone will extend at least 25 feet on either side of the channel. These
areas will be planted with appropriate riparian vegetation as described in Section 6.0
Habitat Restoration. The riparian zone is limited by the urban constraints and the
constraints of an active golf course that includes play that cross the stream channel.
23
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Figure 7: Typical Cross-Sections
-60.00 -40.00 -20.00 0.00 20.(
Off Set from CL (ft)
34.00
32.00
30.00 c
28.00
m
26.00 w
24.00
00
Typical X-Section Pool
33.0
31.0
29.0 0
27.0
m
w
25.0
23.0
-80 -60 -40 -20 0 20 40
Off Set from CL (ft)

7 1.
24 ( I?

Typical X-Section Riffle
W
0 0
C H
Dd
O
3
.L
s ?
? c
? i
_m
-o
cis ;c
m ?
IE
i
1

4' r
:7

32

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s
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LO
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(u) UOIIVAG13
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.2 SEDIMENT TRANSPORT
A stable stream has the capacity to move its sediment load without aggrading or
degrading. The total load of sediment can be divided into bed load and wash load. Wash
load is normally composed of fine sands, silts and clay and transported in suspension at a
rate that is determined by availability and not hydraulically controlled. Bed load is
transported by rolling, sliding, or hopping (saltating) along the bed. At higher discharges,
some portion of the bed load can be suspended, especially if there is a sand component in
the bed load. Bed material transport rates are essentially controlled by the size and nature
of the bed material and hydraulic conditions (Hey 1997).
Critical dimensionless shear stress can be found using Shield's Curve and surface particle
sample from a representative riffle in the reach. A riffle bed surface pebble count was
taken at a riffle on the Middle Branch of Hewlett's Creek. The riffle bed surface d50 was
then calculated to be 0.06 mm. The shear stress placed on the sediment particles is the
force that entrains and moves the particles, in a given channel geometry. From Shields
curve the shear stress that entrains and moves particles in this stream based on the d50 is
.0025 lbs/sgft.
Wetted perimeter was measured off of a CADD file of the typical riffle cross-section
drawn to scale. The wetted perimeter was measured to be 29 ft, while the cross-sectional
area was 30 sgft this produced a hydraulic radius of 1.03. The Slope for the used for the
shear stress calculation is 0.0023. The resultant shear stress for the proposed channel is
0.15 lbs/sgft, this shear stress is sufficient to move the d84 of the riffle bed material,
which is 0.15 mm. Shield's Curve predicts that this stream can move a particle that is, on
average, greater than 5 mm. Since the D84 was 0.15 mm and Shield's Curve predicts 5
mm, the proposed stream has the competency to move its bed load.
Sediment transport analysis was examined at the restoration site through the comparison
of existing and post restoration shear stress analysis. The existing channel does not
appear to be aggrading so it is implied that it is more capable of transporting its
watershed sediment load. Two existing shear stresses are examined and one restored
shear stress. Shear stress is approximated using the equation shear stress = density of
water times the hydraulic radius times the average water surface slope. Existing bankfull
shear stress is 0.233 lbs/sqft. The top of bank shear stress is 0.454 lbs/sqft.
Post restoration, average water surface slope will be decreased and the floodplain will be
established adjacent to the bankfull channel thus lowering the top of bank shear stress
significantly. The post restoration bankfull shear and top of bank shear stress is 0.222
lbs/sgft. These calculations were confirmed with HEC-RAS modeling.
4.3 FLOODING ANALYSIS
This restoration site is not in a mapped FEMA regulatory floodway zone and therefore, is
not subject to FEMA regulations. NCSU design team has also received verification from
26
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
the City of Wilmington Division of Stormwater that this reach of Hewlett's Creek is not
FEMA mapped and does not have a recorded history of flood related incidents. Currently
there are no structures located in the adjacent areas that would be impacted by floodplain
alterations. The Priority 2 restoration of the stream will leave the stream's existing profile
elevations essentially the same. A new floodplain will be established so that the active
stream will be able to access it during larger storm events. Considering the type of
restoration it is assumed that for smaller events the water surface elevations along the
stream shall remain the same. During storms where the stream accesses the newly
establishment floodplain the new water surface elevations are expected to be lower than
the existing water surface elevations of storms of the same magnitude. The restoration
will create neither positive nor negative water surface elevation changes during the larger
storm events (greater than 25-year). HEC-RAS was used to analyze both existing and
proposed conditions after the design was finalized. Sheer stress and flood stages were
compared at various return intervals to evaluate the design.
4.4 STRUCTURES
Several different structures made of natural materials will be installed along the Middle
Branch of Hewlett's Creek. These structures include cross vanes, single vanes, and root
wads. Natural materials such rocks and root wads will be used to create these structures
from off-site sources and on-site sources.
4.4.1 Cross Vane
A cross vane structure serves to maintain the grade of the stream. The design shape is
roughly that of the letter "U" with the apex located on the upstream side at the foot of the
riffle. Footer rocks are placed in the channel bottom for stability. Rocks or logs are then
placed on these footer rocks in the middle of the channel at approximately the same
elevation as the ripple. On either side of the channel, rocks or logs are placed at an angle
to the stream bank, gradually inclining in elevation until they are located above the
bankfull surface directly adjacent to the stream bank. Water flowing downstream is
directed over the vane towards the middle of the channel. Rocks or a log placed at the
apex determine the bed elevation upstream. A cross vane is primarily used for grade
control and to protect the stream banks.
4.4.2 Root Wads
The objectives of these structure placements are as follows: (1) protect the stream bank
from erosion; (2) provide in-stream and overhead cover for fish; (3) provide shade,
detritus, terrestrial insect habitat: (4) look natural, and (5) provide diversity of habitats
(Rosgen 1996). A footer log and boulder are placed on the channel bottom abutting the
stream bank along an outside meander that will provide support for the root wad and
additional stability to the bank. A large tree root wad is then placed on the stream bank
with additional boulders and rocks on either side for stability. Flowing water is deflected
away from the bank and towards the center of the channel.
27
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
4.4.3 Single Vane
A single vane structure serves to maintain the pattern of the stream. Footer rocks are
placed in the channel bottom for stability. Rocks or logs are then placed on these footer
rocks in the middle of the channel at approximately the same elevation as the ripple. On
either side of the channel, rocks or log is placed at an angle to the stream bank, gradually
inclining in elevation until they are located above the bankfull surface directly adjacent to
the stream bank. Water flowing downstream is directed over the vane towards the middle
of the channel. A single vane is primarily used to turn the stream flow and control and to
protect the stream banks.
Specific location of these structures will be determined during final design.
28
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
5.0 HABITAT RESTORATION
The restoration plan requires the establishment of riparian vegetation at the site. The
proposed vegetation is described in the following sections.
5.1 VEGETATION
Vegetation that develops a quick canopy, has an extensive root system, and a substantial
above-ground plant structure is needed to help stabilize the banks of a restored stream
channel in order to reduce scour and runoff erosion. In natural riparian environments,
pioneer plants that often provide these functions are alder, river birch, silky dogwood,
and willow. Once established, these trees and shrubs create an environment that allows
for the succession of the other riparian species including ashes, black walnuts, red
maples, sycamores, oaks, and other riparian species.
In the newly restored stream channel, revegetation will be vital to help stabilize the
stream banks and establish a riparian zone around the restored channel. Revegetation
efforts on this project will emulate natural vegetation communities found along relatively
undisturbed stream corridors. To quickly establish dense root mass along the channel
bank, a native grass mixture will be planted on the streambed and bank. Shrubs will be
utilized on the stream bank and along the floodplain to provide additional root mass.
Extra care will be given to the outside of the meander bends to ensure a dense root mass
in those areas of high stress. Coir matting or similar material will be used to provide
erosion protection until vegetation can be established. Along the tops of the channel
banks, trees, shrubs and a native grass mixture will be planted.
A mixture of seeds, live stakes, bare root, as well as balled in burlap nursery stock, some
2 "- 4" caliper tree and transplants will be used to stabilize the banks. Proposed species
to be planted included, but are not limited to:
Trees
Blackcherry (Prunus serotina)
Blackgum (Nyssa sylvatica)
Loblolly Bay (Gordonia lasianthus)
River Birch (Betula nigra)
Sugarberry (Celtis laevigata)
Shrubs
American hornbeam (Carpinus caroliniana)
Fetter bush (Lyonia lucida)
Inkberry (Ilex glabra)
Marsh mallow (Hibiscus moscheutos)
Silky dogwood (Corpus amomum)
Sweet pepperbush (Clethra alnifolia)
Virginia willow (Itea virginica)
29
Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Herbs- Permanent seed mixture
Deertongue (Panicum clandestinum)
Purple love grass (Ergrostis spectabilis)
Switch Grass (Panicum virgatum)
Tussock sedge (Carex stricta)
Other herbaceous vegetation
Dwarf spike-rush (Eleocharis parvula)
Ironweed (Vernonia noveboracensis)
Jack-in-the-pulpit (Arisaema triphyllum)
Woody vegetation will be planted between February and May to allow plants to stabilize
during the dormant period and set root during the spring season. In the areas where
invasive and exotic species are located, during construction and monitoring control by
removal or appropriate herbicides will be implemented to prevent competition with the
revegetation efforts.
5.2 RIPARIAN BUFFERS
At least three different types of riparian buffers will be employed to vegetate the restored
channel. All buffers will use plants native to the coastal plain region of North Carolina.
In areas where the fairways cross the stream channel, vegetation will be kept to a minimal
height so as not to obstruct views and play within the crossing. The areas along the city
sewer line (within approximately 10' to either side of the utility) will be planted with
vegetation having shallow (limited) root structure so that the sewer line and access to it
shall not be impacted or impeded. The remaining areas will be planted with native trees,
shrubs, grasses and other herbaceous vegetation in order to restore natural coastal plain
plant communities. Proposed species to be planted include but are not limited to those
listed in the above section
5.2.1 Temporary Seeding
A temporary seed mixture will be applied to all disturbed areas immediately after
construction activities have completed. This temporary seed mixture will provide erosion
control until permanent seed can become established. Permanent seed will be native to
the coastal region of North Carolina.
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Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
6.0 MONITORING
6.1 STREAM CHANNEL
Monitoring of the stability of the channel is recommended to occur approximately 6
months after restoration is complete or after bankfull (or greater) events and should
continue annually for a period of 3 to 5 years. Monitoring practices may include, but are
not limited to, installing bank erosion pins and a toe pin, monumented cross-sections,
scour chains, macroinvertebrate studies, longitudinal profiles, conducting the bank
erosion hazard rating guide and establishing photo reference points. The purpose of
monitoring is to determine bank stability, bed stability, morphological stability and
overall channel stability. Table 4, below, can be used for selecting practices.
Table 3. Stream Monitoring Practices
PRACTICE STABILITY ASSESSMENT
Bank Erosion Pins with Toe Pin -Lateral or bank stability
Monumented Cross-Section -Vertical or bank stability
-Lateral or bank stability
Scour Chains -Vertical or bed stability
-Scour depth fora articular storm
Scour Chain w/ Monumented
Cross-Section -Vertical or bed stability
-Sediment transport relations
-Biological interpretations
Longitudinal Profile -Channel profile stability
Bank Erosion Hazard Guide -Bank erosion potential
Photo Reference Points -Overall channel stability
Macroinvertebrate -Biological indication of water quality
6.2 VEGETATION
Prior to planting, the site will be inspected and checked for proper elevation and
suitability of soils. Availability of acceptable, good quality plant species will be
determined. The site will be inspected at completion of planting to determine proper
planting methods, including proper plant spacing, density, and species composition.
Competition control will be implemented if determined to be necessary during the early
stages of growth and development of the tree species. Quantitative sampling of the
vegetation will be performed between August 1 and November 30 at the end of the first
year and after each growing season until the vegetation criteria is met.
In preparation for the quantitative sampling, 50 by 50 feet (0.05-acre) vegetative plots
will be established in the reforested area. Plots will be evenly distributed throughout the
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Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
site. For each plot, species composition and density will be reported. Photo points will be
taken within each zone. Monitoring will take place once each year for five years.
Success will be determined by survival of target species within the sample plots. At least
six different representative tree species should be present on the entire site. If the
vegetative success criteria are not met, the cause of failure will be determined and
appropriate corrective action will be taken.
6.3 MACROIN VERTEBRATES
A monitoring period of 3 to 5 years is commonly suggested to determine changes in
macroinvertebrate populations within a newly restored stream. The North Carolina
Wetlands Restoration Program will determine a macroinvertebrate monitoring policy.
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Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
7.0 REFERENCES
Amoroso, J.L., ed. 1999. Natural Heritage Program List of the Rare Plant Species of
North Carolina. North Carolina Natural Heritage Program, Division of Parks and
Recreation, North Carolina Department of Environment and Natural Resources. Raleigh,
North Carolina.
Cowardin, L.M., V. Carter, F.C. Golet and E.T. LaRoe. 1979. Classification of Wetlands and
Deepwater Habitats of the United States. U.S. Fish and Wildlife Service, Office of
Biological Services, FWS/OBS-79/3 I. U.S. Department of the Interior, Washington, DC.
Choate, J.R., J.K. Jones, Jr., and C. Jones. 1994. Handbook of Mammals of the South-Central
States. Louisiana State University Press, Baton Rouge, Louisiana.
Doll, B. A., et al. 2000. Hydraulic Geometry Relationships for Urban Streams throughout the
Piedmont of North Carolina. American Water Resources Association.
Godfrey, R.K., and J.W. Wooten. 1979. Aquatic and Wetland Plants of Southeastern United States.
Monocotyledons. The University of Georgia Press, Athens, Georgia.
Godfrey, R.K., and J.W. Wooten. 1981. Aquatic and Wetland Plants of Southeastern United States.
Dicotyledons. The University of Georgia Press, Athens, Georgia.
Harrelson, Cheryl, C.L. Rawlins and John Potyondy. 1994. Stream Channel Reference Sites: An
Illustrated Guide to Field Technique. United States Department of Agriculture, Forest Service.
General Technical Report RM-245.
Hey, Richard and Dave Rosgen. 1997. Fluvial Geomorphology for Engineers. Wildland Hydrology,
Pagosa Springs, Colorado.
LeGrand, H.E., Jr. and S.P. Hall, eds. 1999. Natural Heritage Program List of the Rare
Animal Species of North Carolina. North Carolina Natural Heritage Program, Division of
Parks and Recreation, North Carolina Department of Environment and Natural
Resources. Raleigh, North Carolina.
NCDENR. "Water Quality Stream Classifications for Streams in North Carolina." Water Quality
Section. http:/Ih2o.enr.state.nc.us/wghome.htmi (16 July 2001).
Radford, A.E., H.E. Ahles and G.R. Bell. 1968. Manual of the Vascular Flora of the Carolinas. The
University of North Carolina Press, Chapel Hill, North Carolina.
Rosgen, Dave. 1997. A Geomorphological Approach to Restoration of Incised Rivers.
Wildland Hydrology. Proceedings of the Conference on Management of Landscapes
Disturbed by Channel Incision.
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Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
Schafale, M. P. and A. S. Weakley. 1990. Classification of the Natural Communities of
North Carolina: Third Approximation. North Carolina Natural Heritage Program.
Raleigh, North Carolina
United States Department of Agriculture - Soil Conservation Service. December, 1977. "Soil
Survey of Guilford County, North Carolina." US Government Printing Office, Washington,
DC.
United States Fish and Wildlife Service. "Region 4, Southeast Region/Endangered Species." North
Carolina Ecological Services. http://nc-es.fws.gov/ (August 2001).
USDA, NRCS. 2001. The PLANTS Database, Version 3.1 (http://plants.usda.gov). National Plant
Data Center, Baton Rouge, LA 70874-4490 USA.
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Stream Restoration Plan
The Middle Branch of Hewlett's Creek
New Hanover County, NC
2.2.5 Wildlife Observations
Wildlife and signs of wildlife were noted during on-site visits, however, a formal wildlife
survey was not performed. Tracks of white tailed deer (Odocoileus virgin ianus) and
raccoon (Procyon Iotor) were observed along the stream banks. A variety of birds were
observed in the thickets and shrubs surrounding the stream channel and forest, including:
vanous sparrows.
2.2.5.1 Possible Invasive Wildlife
The following species were identified during site visits to the Middle Branch of Hewlett's
Creek; Asian tiger mosquito (Aedes albopictus), Bullfrog (Rana catesbeiana) (auditory
identification), European gypsy moth (Lymantria dispar), and European starling (Sturnus
vulgaris). The bullfrog is listed based on auditory identification by one of the project
researchers. The gypsy moth is listed based on visual identification of nests. The
mosquito and starling are listed due to their ubiquitous nature.
2.2.6 Endangered Species
The NCSU design team has not identified endangered plant or animal species or any such
habitat that would support the endangered species listed in this section. The NCSU
design team has made multiple visits to the Pine Valley Country Club and the restoration
site. Below is a list obtained from Natural Heritage, of the endangered of concern for
New Hanover County.
2.2.6.1 Endangered Flora
Vascular Plants:
Cooley's meadowrue
Rough-leaved loosestrife
Seabeach amaranth
Bog St. John's-wort
Carolina asphodel
Carolina bishopweed
Carolina beaksedge
Chapman's sedge
Coastal golden rod
"Dune bluecurls"
Pickering's dawnflower
Pondspice
Sandhills milkvetch
Savanna indigo-bush
Spiked medusa
Spring-flowering goldenrod
Tough bumelia
Endangered
Endangered
Threatened
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
Federal Species of Concern
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