20021681 Ver 1_Complete File_20001122

W A TFRO Michael F. Easley
\? G Governor
Cq William G. Ross, Jr., Secretary
j y Department of Environment and Natural Resources
Alan Klimek, RE
Division of Water Quality
November 22, 2002
Mr. Jeff Jurek
Wetlands Restoration Program
1619 MSC
Raleigh, NC 27699-1619
Subject: Stream Restoration/Enhancement
Little Sugar Creek/Freedom Park
Mecklenburg County, NC
DWQ# 021681
Dear Mr. Jurek:
This Office is in receipt of the plans for the stream restoration projects of approximately 4500 feet of
Little Sugar Creek in the Catawba River Basin originally submitted to this Office on October 15, 2002, and
finalized November 22, 2002. DWQ Staff reviewed the plans and determined that stream restoration and/or
enhancement would be achieved as long as the following stipulations are met:
1) Bank to bank rip rap shall not be applied above Dairy Branch as described in the application or response
letter.
2) Toe hardening shall not be conducted between vanes as shown in the Rock Vane typical plan, except to
protect a specific structure such as a bridge or sewer line.
As long as the above conditions are met, the stream impacts associated with the project may proceed without
written approval from the Division. Please be advised that seven copies of a complete, formal application and a
$475.00 fee is required for projects intended for compensatory mitigation credit (see General Certification No.
3353, issued March 18, 2002). Any request for mitigation credit shall be addressed under separate cover.
If you have any questions regarding this matter, please contact Mr. Todd St. John at [phone].
S
W
cc:
Mr. Todd St. John, Wetlands Un
Mooresville Regional Office
File
orn
Unit Supervisor
North Carolina Division of Water Quality, 401 Wetlands Certification Unit,
1650 Mail Service Center, Raleigh, NC 27699-1650 (Mailing Address)
2321 Crabtree Blvd., Raleigh, NC 27604-2260 (Location)
Responses to NCDWQ Questions on Freedom Park Project
Responses to DWQ questions appear below each DWQ statement or question.
¥Y. GC Conditions - FYI
Bank hardening of over 500 feet (measured per bank) requires a formal
application and fee. The designer wants to use bank to bank rip rap just
upstream of Dairy Branch for 300 feet per bank for a total of 600 feet.
The extent and nature of this should be included on the plans. Also, I
assume that the Mannings n referred to should be 0.045.
• We will adjust the plans so that up to 2001f of bank on either side of the channel, above Dairy
Branch, will be protected with bank to bank rip rap, for a total of no more than 400 feet.
¥¥. In Stream Structures, Channel Plug Blocks and Bank Stabilization
Please provide complete typical plans for all types of structurestbank
revetments proposed. Not provided: anchored log wing deflector, channel
plug, rock vane, root wad, coir fiber and biolog at toe, bankfull bench.
• Copies of these details will be sent to NCDWQ care of WRP.
For Riffle Type 1 ,2 and 3 - Please provide the specific D50 sizes. The
size of the rocks used for the crest and regular cross vane should be
very large, such as 4 ft x 3 ft x 5 ft. The rocks tend to move as a
result of undermining and not tractive or drag forces alone. These
should also have footers of equal or greater size. Geotextile lining
and/or graded materials must also be provided on the upstream side of
the rock vanes. Please provide the depth of the rock added in the
riffles. Please provide the vertical and horizontal angles and relative
lengths of the vane arms. Please discuss how high the vane arms will be,
on the banks.
• D50's for riffle armor (excluding crest and cross vane) and riffle matrix/substrate are provided in
table 1.
• We agree that the sizes of the rocks in the cross vanes and along riffle crests should be larger than
that required by traction calculations, as suggested.
• Can the DWQ provide an example or a detail indicating the fashion by which geotextile lining
should be used? This applies to cross vans, wing rock vanes and log toe support.
• Please provide additional technical details for the use of a graded material in lieu of geotextile
lining (e.g. min and max sizes) required by DWQ should the use of graded material be deemed
feasible.
• The depth of rock at each riffle will directly depend on the presence and elevation of in-situ
bedrock or `c' horizon saprolite, and the available elevation change across each riffle and pool
cycle. Therefore, the depth of riffle material will be determined in the field.
• The vane arm positions and vertical/horizontal angles are indicated on the updated detail.
• Can the design team size the riffle crest, wing vane and cross vane material to 1.5 - 2 times the
diameter expected to be moved by bed traction forces at the 100-yr flood level? This, used in
conjunction with footers of similar size, should provide a sufficient safety margin for
undermining. For nominal conditions in the reach such calculations yield sizes close to those
suggested (3 x 4 x 5 ft). Low gradient riffles with very small drops in elevation, e.g. 6" - 10" will
not perform well and will have installation problems if constructed with boulders with diameters 5
times the total grade drop.
Inner Berm and Point Bar Constrictors - I have seen similar structures
provided for inner berms; however, it is not clear why such a structure
would be used at a point bar since point bars tend to be depositional
features consisting of mobile material. This may effect sediment
transport negatively. Is this the same structure referred to as a
bankfull bench above?
The inner berm/point bar constrictors are not the same as a bankfull bench. These features, like
their natural counterparts (inner meander bend berms), often lie at slightly lower stage levels that
the bankfull stage. The inner portions of these inner berms (inside the point bar) are aggradational
features, typically stabilized by multiyear vegetation. These berms are needed in the design to
constrict the channel back to appropriate dimensions in meander bend areas. The structures do not
restrict point bar material mobility, as the lower unvegetated point bar lies on the thalweg side of
the berm's coir fiber/biolog that is used to provide a stable zone for bioengineering.
¥¥. Morphological Measurements
The morphological measurements provided seem to indicate that the data
provided by the USACE is incorrect. However, key parameters such as
bankfull width, depth and cross sectional area were still used for Brier
Creek. They did not provide pool to pool spacing information. I
extrapolated it from the longitudinal profiles. I got about 270 feet for
the design stream and about 220 feet for Brier Creek. Are these numbers
correct?
The only errors in the USACE data that were found were related to slope. The team performed in-
field measurements to produce a reliable replacement longitudinal profile.
Pool and riffle spacing can be expressed in a variety of ways. Our calculations show that the
average distance from the beginning of one pool to the next for the design stream is 197 ft; if the
DWQ provide a description of the method that they used to calculate the pool to pool we can
verify their estimates.
¥¥. Sediment Transport Analysis
The designer used bar data in their sediment transport analysis which
as you know is suspect in North Carolina. I calculated a compentcy for a
"largest particle" of about 65 mm. I am not certain if the numbers in
table 1 are actual numbers or calculated. Please have them clarify (i.e.
I am not familiar with D85 high or low).
Sedimentology data were collected from the depositional environments with both the impaired and
reference streams and used to determine the design D50 and D84's for riffle matrix/substrate and
pool bed materials. The D84's are the 84% coarser, or finer, than by weight diameters, and
provide a means to maintain appropriate size distributions when using the data to estimate design
parameters. The D84 (upper diameter) values are also useful as a check on Shield Curve
estimates.
The design D50 and D84 sizes for riffle armor are based on a Shield curve analysis and the
Newbury and Gaboury criteria, and provide for particle stability during a true top of bank event.
The approack is consistent with the DWQ comments above on the size of rock required to be
stable in a cross vane.
¥¥. Reference Reach
The designer did not seem very confident in their own reference streams
and seem to imply that one was recently disturbed to the point of
rendering it inappropriate and the other is incised. Are you satisfied
with their reference streams?
More importantly, it is not clear how bankfull elevations were
determined for the reference or design streams. This is obviously
critical if they are designing a C or E type stream. (It would be less
critical for a Bc type stream.) Please have the applicant clearly
discuss how they determined bankfull. If they could not identify it on
their reference streams by field indicators how can the reference
streams be considered appropriate? I do not agree that back calculating
bankfull based on a 1.5 year return interval discharge is appropriate
(if that's what was done). All of the information that I have ever
received would indicate that the return interval in urban areas is
closer to a 1.1 or 1.2 year event. Also, over sizing the channel based
on anticipated build out may also be risky. The cross sections for the
riffle sections of the design stream are reminiscent of Bc type streams.
In this case, it may be better to more accurately estimate bankfull than
it would be to over estimate it since there is a slope break at the
proposed bankfull elevation.
Concerns have been expressed regarding the designer's level of confidence in
the reference reach foundations for the design. In regards to these
concerns, we have the following comments.
1. The reference reach data collected and developed for Long Creek provided no indications
of the reach being out of equilibrium. The upper portion of the reach
traverses a granite bedrock ridge with no indications of recent incision. The
lower end of the reach has areas of the flood plain with elevations very
close to observed indicators of the bankfull stage. Streams in the North
Carolina Piedmont that are developed in granitic and high grade metamorphic
terranes typically show alternating degrees of `incision' as they traverse
resistant and less resistant bedrock formations. With the stream
encountering these resistant ledges every few hundred feet or so, it is unreasonable
or impractical to break up these streams into small segments of
differing stream type, as these types would vary at scales less than one
meander wavelength. Stream segments this short would not be long enough to
allow the collection of a reasonable set of objective and representative
morphologic parameters. The `incision' referred to in the comments from
NCDWQ is a natural characteristic of this reference reach, and does not in
any way lessen our confidence of it's use as a design benchmark.
The lower end of Freedom Park has extensive bedrock and would also likely have had
similar `incised' cross section profiles due to the resistance of bedrock to
chemical and mechanical erosion. Incision is a balance of regional rates of
chemically dependent soil formation on the stream-side hillslopes and the
mechanical processes of stream erosion that degrade the bed of the stream
channel. Areas with very low rates of hill slope degradation will show high
values of stream `incision' with equal, or even less than equal, rates of
channel bed degradation.
2. All bankfull values are morphologically-based. Along Long Creek, the
upper limit of the undercutting of banks along with the upper elevations of
bank berms, which are developed in several areas, provided a clear and
internally consistent indication of the bankfull stage. The accuracy of
these indicators is supported by the observation at the lower end of the
reference reach, of floodplain areas near the creek banks that extend down to
within 6-12" of the heights of the bankfull indicators. In regards to the
earlier USACOE study (Briar Creek), we observed along the upper end of the
reach, an inner berm with an inner berm elevation yielding a mean Bf height
of 6-6.5 ft, thus confirming that the USACOE values
are consistent with morphologic indicators at this site. This berm had
seasonal accumulations of silt and sand (+dated garbage) and is an active
(i.e. not abandoned terrace) morphologic feature in the channel.
3. A review and field verification of the data included in the earlier
USACOE study indicated that the only data inconsistent with site conditions
were those arising from the earlier study's longitudinal profile. Since it
was not clear where the longitudinal data were collected in the earlier
study, a new longitudinal profile was collected for this design. The
longitudinal profile generated data consistent with valley slope and stream
sinuosity derived from County/City engineering maps.
In addition, new aerial photographs were acquired over this reference reach to verify that no recent
stream work had been completed in the reference reach areas along Briar
Creek. Briar Creek had been the focus of recent stream enhancement activity
by Meck. Co. Stormwater Services, and their areas of disturbance could be
clearly identified on the new aerial photos. In addition to the data
collected in the prior study and the new longitudinal data collected for this
study, other down stream segments of Briar Creek that show no signs of
historical modifications in planform (back to 1930's) or it's wooded banks
were included to expand the data set for planform geometry (e.g. meander
wavelength & radii of curvature). The prevalence of bedrock along the bed of
Briar Creek in the reference reach area and the long term stability of the
wooded riparian landuse lends strong support to the accuracy of the
longitudinal profile and planform data from this reach.
Bankfull indicators were determined from morphologically-based active features in the channel.
Even if the original cross section of Briar Creek had been modified, either
in the early part of the 20th century when the larger creeks in Meck. Co.
were dredged and widened, or later when the sewer line was emplaced along the
east side of the creek, the noted active morphologic bankfull features would
represent current, adapted, bankfull conditions. Had the Bankfull stage
fallen since human disturbance, the inner berm would have been transformed
into a vegetated terrace. Thus it is not possible for bankfull to be lower
that the current height of seasonal deposition on these inner berms.
4. The design approach in this project relies most heavily on the reference
reach datasets, but also verifies these values with other sources of
important information including USGS data from Briar, Little Sugar, and Long
Creek; NC regime data for the Piedmont Province; and up stream and down
stream conditions observed in Little Sugar Creek.. The comments from NCDWQ
seem most concerned with the bankfull stage heights. The design did not use
USGS discharges for any `back calculated' bankfull estimations. The bankfull
area and stage values chosen for the design are consistent with values
interpolated from both reference reach datasets. They are also consistent
with the NC regime datasets. However, given the level of concern expressed
by NCDWQ, we have re-examined this issue and note two additional
observations.
First, in an earlier study of Little Sugar Creek to determine
the feasibility of a full restoration at the Midtown Mall site (upstream
from Freedom Park), a morphologic study was done upstream from the Midtown
Mall, where the creek has vegetated banks and runs at a similar slope as in
Freedom Park. In this earlier study, four bankfull cross section areas were
estimated from cross sections taken at locations with active depositional
inner berms or bank benches on one bank or the other. These cross sections
yielded bankfull areas (for a watershed with approximately 1-2 square miles
of less drainage than Freedom Park) with a range from 305 to 350 square feet
(personal data of R. Forsythe). The independently derived estimates used for
our design are consistent with these values.
Secondly, stage and bankfull area rating curves, along with time series of annual peak flows from gaging
stations along Briar, Long, and Little Sugar Creek, were provided in the appendices of
the design plan. If one takes the 305-350 bankfull areas from the Midtown
area and uses the rating curves for the Medical center gaging station located
just a few thousand feet down stream, it can be verified that discharges are
as predicted for the upper end of Little Sugar Creek at Freedom Park
(approximately 1600 cfs). If anything, it may be concluded that the 1.5 year
return interval-based Q estimates are on the low side, not high side.
5. There were suggestions in the review that the bankfull event should have
a return inteval of closer to 1, not 1.5 years. This may be true in many
urban streams and watersheds, but much of this database arises from creeks
which have not been extensively dredged and widened. Upstream from Freedom
Park, the Little Sugar Creek channel persists in an over-widened and
partially channelized state and has sediment transport characteristics which
reflect both a higher frequency of flows of a given magnitude(Q) but also
much lower bed traction forces due to widening. For example, north of the
Midtown Mall the banktoe-to-banktoe distance is almost 40 feet, not the
original 15-20 feet. These alterations have lowered bed shear stresses for
any given Q return interval storm and work to counter the typical trends
observed in urban watersheds which have non-widened stream channels. Without
widening, one would expect that the system's sediment transport
characteristics would be highly dependent on threshold levels of bed shear
stresses, which would indeed become more frequent with urbanization.
However, since the bed shear stresses were lowered for any given Q by
widening of the channel this relationship may actually be reversed. This
inverse response is what produces the aggradational characteristics (i.e.
alternating lateral bars) that has been noted worldwide for widened channels.
It is this difference which I believe sits at the root of the discrepancies
noted in the NCDWQ comments.
To conclude, our design has bankfull characteristics which are consistent
with: a) morphologically-based data arising from two independent reference
reach datasets; b) observations on bankfull area and discharge collected up
stream on the design stream; and c) the North Carolina regime data sets.
Exactly what return interval the bankfull discharge should, or should not, have
is conjectural and not easily predicted given the altered conditions of
the upstream channel. The estimates made here for a 1.5 year return interval
are based on reasonable scientific grounds.
North Carolina
Department of Environment and Natural Resources LTJWVWA
?„?. 00
Michael F. Easley, Governor William G. Ross Jr., Secretary NCDENR
NC UPT, 07 771 AlUIONIMENT
A?*`? ki ; -rr to
MEMORANDUM: OPT if???. _
TO: John Dorney WAS jUNpS GROUP
UAIIry SfCtroN
OCT 1 V
FROM: Jeff Jurek
SUBJECT: Permit Application-Freedom Park
DATE: 10-11-02
Attached for your review are 2 restoration plans (1 sent to Mooresville) for the Freedom
Park Stream Restoration project in Mecklenburg County. Please feel free to call me with
any questions regarding this plan (733-5316).
Thank you very much for your assistance.
attachment: Restoration Plan (2 originals)
r l041t
?C

Wetlands Restoration Program 1619 Mail Service Center Raleigh, NC 27699-1619
[phone] Fax: [phone]
.W.
Office Use Only: Form Version October 2001
USACE Action ID No. DWQ No.
If any particular item is not applicable to this project, please enter "Not Applicable" or "N/A" rather than
leaving the space blank.
1. Processing
1. Check all of the approval(s) requested for this project:
® Section 404 Permit
? Section 10 Permit
® 401 Water Quality Certification
? 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
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]
2. Agent 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:
Company Affiliation:
Mailing Address:
Telephone Number: Fax Number:
E-mail Address:
Page 5 of 12

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 Freedom Park Stream Project
2. T.I.P. Project Number or State Project Number (NCDOT Only):
3. Property Identification Number. (Tax PIN): -_
4. Location
County: Mecklenburg Nearest Town Charlotte
Subdivision name (include phase/lot number):
Directions to site (include road numbers, landmarks, etc.): See plan
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: City
Park-Recreation
7. Property size (acres): 15-17 ac
8. Nearest body of water (stream/river/sound/ocean/lake): Little Sugar Creek
9. River Basin: Catawba
(Note - this must be one of North Carolina's seventeen designated major river basins. The
River Basin map is available at http:Hh2o.enr.state.nc.us/admin/maps/.)
s
10. Describe the purpose of the proposed work: Stream Restoration
Page 6 of 12
11. List the type of equipment to be used to construct the project: Track Hoes, loaders
12. Describe the land use in the vicinity of this project: Urban Parks
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
Wetland Impact Type of Impact* Area of Located within Distance to
Page 7 of 12

Site Number
(indicate on ma) Impact
(acres) 100-year Floodplain**
(es/no) 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.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:
Total area of wetland impact proposed:
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?
(please secif )

* 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: 4500 Fr.
3. Open Water Impacts, including Lakes, Ponds, Estuaries, Sounds, Atlantic Ocean and any
other Water of the U.S.
Page 8 of 12
Open Water Impact
Site Number
(indicate on ma)
Type of Impact* Area of
Impact
(acres)
Name Watble)
(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.
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
Page 9 of 12

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.nc.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 PLAN
2. Mitigation may also be made by payment into the North Carolina Wetlands Restoration
Program (NCWRP) with the NCWRP's written agreement. Check the box indicating that
you would like to pay into the NCWRP. Please note that payment into the NCWRP must be
reviewed and approved before it can be used to satisfy mitigation requirements. Applicants
will be notified early in the review process by the 401/Wetlands Unit if payment into the
NCWRP is available as an option. For additional information regarding the application
process for the NCWRP, check the NCWRP website at biip://h2o.enr.state.nc.us/m/index.htm. If
use of the NCWRP is proposed, please check the appropriate box on page three and provide
the following information:
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 (DWQ Only)
Page 10 of 12
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 3U feet perpendicular tiom near bank of channel; Zone L 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
Page 11 of 12
Payment into the Riparian Buffer Restoration Fund). Please attach all appropriate information as
identified within 15A NCAC 2B .0242 or.0260.
XI. Stormwater (DWQ Only)
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 (DWQ Only)
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 (DWQ Only)
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
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).

Applicant/A/(,-ntYSXnature Date
(Agent's si atu?te i valid only if an authorization letter from the applicant is provided.)
Page 12 of 12
1 u. wlam or noon rone area
11. entrenchment ratio -V
5.88 C or E
0.00 CHECK
12 meander length 395 550 567.4133
13 ratio of meander length to bankfull width
14. Radius of curvature
160 7.75 too small?
94 11.22 ok
96.97608 mm
15. Ratio of radius of curvature to bankfull width 3.14 ok 1.92 __ ---
16. Belt width _?- 200 - 150 154.7491
17. Meander width ratio 3.92 3.06 _
18. Sinuosity (stream IengthNallelength) 1.11 1.12 1.1 1.09
19. Valley Slope 0.0029 0.0048
20. Average sloe 0.0026 0.0044
21. Pool slope _
? 0
- - _ ,-___.._..„ _-_..._._...-._.._._.,.-?.....„.._.._..
22. Ratio of pool slope to avera a slo a ?T 0.00 0.00 _
23 Maximum pool depth 0
24 Ratio of pool depth to average bankfull depth 0.00 too small? 0.00 too small?
25. Pool width 0
9a A,rn nf „nni width to hn„kfi al width 0.00 30.888015 0.00
27. Pool to pool spacing 272 n1a______ __ 220 22b.96b3
150
200
250
225
310
310
400
225
325
200
275
200
225
390
400
272.3333
28. Ratio of of to colspacing to bankfull width 5.33 C or E 4.49 A or B
29. Ratio of lowest bank height to bankfull height (or max bankfull depth)
X-Sec
193.1197947 423.3437396 37.530919
41.911173
Sediment Transport Analysis ala Rosgen for D50 >2mm
d50 mm 4.8 mm active channel D50 only
ds50 mm 2.6 mm subsurface D50
Tci 0.048863 dimensionless
Tci 0.048863
Di (largest) f 0.213255
avg bed S ft/ft 0.0026
Dbkf propose 6.5
mean Dbkf needed 6.612862
Di mm 65 mm
BKF A 335 ft2
wetted perirr 73.51666 ft
gRS=Tc 0.739294 lb/ft2
diagram Shields pred. 65 mm
diagram Shields pred Ibs/ft2
average bed slope for reach not just riffle
Variables Proposed Reach Check Results Reference Reach Check Results Range SGS Staticstin Channel
Rural Piedmont -? -- -- _-„ 130.2525229 601.8009756 37.221795 3.506883704
Rural Mountain- 131.3465712 756.3836409 50.857474 2.527127437
Coastal Plain 97.49461968 158.5746042 30.357468 3.370029737
Little Sugar DWQ#021681
Subject: Little Sugar DWQ# 021681
Date: Fri, 25 Oct 2002 12:50:15 -0400
From: "Todd St. John" <[e-mail]>
Organization: DWQ Wetlands Unit
To: [e-mail]
CC: "Todd St. John" <[e-mail]>
YY. GC Conditions - FYI
Bank hardening of over 500 feet (measured per bank) requires a formal
application and fee. The designer wants to use bank to bank rip rap just
upstream of Dairy Branch for 300 feet per bank for a total of 600 feet.
The extent and nature of this should be included on the plans. Also, I
assume that the Mannings n referred to should be 0.045.
YY. In Stream Structures, Channel Plug Blocks and Bank Stabilization
Please provide complete typical plans for all types of structures/bank
revetments proposed. Not provided: anchored log wing deflector, channel
plug, rock vane, root wad, coir fiber and biolog at toe, bankfull bench.
For Riffle Type 1 ,2 and 3 - Please provide the specific D50 sizes. The
size of the rocks used for the crest and regular cross vane should be
very large, such as 4 ft x 3 ft x 5 ft. The rocks tend to move as a
result of undermining and not tractive or drag forces alone. These
should also have footers of equal or greater size. Geotextile lining
and/or graded materials must also be provided on the upstream side of
the rock vanes. Please provide the depth of the rock added in the
riffles. Please provide the vertical and horizontal angles and relative
lengths of the vane arms. Please discuss how high the vane arms will be
on the banks.
Inner Berm and Point Bar Constrictors - I have seen similar structures
provided for inner berms; however, it is not clear why such a structure
would be used at a point bar since point bars tend to be depositional
features consisting of mobile material. This may effect sediment
transport negatively. Is this the same structure referred to as a
bankfull bench above?
YY. Morphological Measurements
The morphological measurements provided seem to indicate that the data
provided by the USACE is incorrect. However, key parameters such as
bankfull width, depth and cross sectional area were still used for Brier
Creek. They did not provide pool to pool spacing information. I
extrapolated it from the longitudinal profiles. I got about 270 feet for
the design stream and about 220 feet for Brier Creek. Are these numbers
correct?
YY. Sediment Transport Analysis
The designer used bar data in their sediment transport analysis which
as you know is suspect in North Carolina. I calculated a compentcy for a
"largest particle" of about 65 mm. I am not certain if the numbers in
table 1 are actual numbers or calculated. Please have them clarify (i.e.
I am not familiar with D85 high or low).
YY. Reference Reach
The designer did not seem very confident in their own reference streams
and seem to imply that one was recently disturbed to the point of
rendering it inappropriate and the other is incised. Are you satisfied'
with their reference streams?
1 of 2 10/25/02 12:53 PM
Little Sugar DWQ# 021681
More importantly, it is not clear how bankfull elevations were
determined for the reference or design streams. This is obviously
critical if they are designing a C or E type stream. (It would be less
critical for a Bc type stream.) Please have the applicant clearly
discuss how they determined bankfull. If they could not identify it on
their reference streams by field indicators how can the reference
streams be considered appropriate? I do not agree that back calculating
bankfull based on a 1.5 year return interval discharge is appropriate
(if that's what was done). All of the information that I have ever
received would indicate that the return interval in urban areas is
closer to a 1.1 or 1.2 year event. Also, over sizing the channel based
on anticipated build out may also be risky. The cross sections for the
riffle sections of the design stream are reminiscent of Bc type streams.
In this case, it may be better to more accurately estimate bankfull than
it would be to over estimate it since there is a slope break at the
proposed bankfull elevation.
Todd St. John, P.E.
Environmental Engineer II
DWQ
Wetlands Unit
2 of 2 10/25/02 12:53 PM
Little Sugar DWQ# 021681
Subject: Little Sugar DWQ# 021681
Date: Fri, 25 Oct 2002 12:50:15 -0400
From: "Todd St. John" <[e-mail]>
Organization: DWQ Wetlands Unit
To: [e-mail]
CC: "Todd St. John" <[e-mail]>
YY. GC Conditions - FYI
Bank hardening of over 500 feet (measured per bank) requires a formal
application and fee. The designer wants to use bank to bank rip rap just
upstream of Dairy Branch for 300 feet per bank for a total of 600 feet.
The extent and nature of this should be included on the plans. Also, I
assume that the Mannings n referred to should be 0.045.
YY. In Stream Structures, Channel Plug Blocks and Bank Stabilization
Please provide complete typical plans for all types of structures/bank
revetments proposed. Not provided: anchored log wing deflector, channel
plug, rock vane, root wad, coir fiber and biolog at toe, bankfull bench.
For Riffle Type 1 ,2 and 3 - Please provide the specific D50 sizes. The
size of the rocks used for the crest and regular cross vane should be
very large, such as 4 ft x 3 ft x 5 ft. The rocks tend to move as a
result of undermining and not tractive or drag forces alone. These
should also have footers of equal or greater size. Geotextile lining
and/or graded materials must also be provided on the upstream side of
the rock vanes. Please provide the depth of the rock added in the
riffles. Please provide the vertical and horizontal angles and relative
lengths of the vane arms. Please discuss how high the vane arms will be
on the banks.
Inner Berm and Point Bar Constrictors - I have seen similar structures
provided for inner berms; however, it is not clear why such a structure
would be used at a point bar since point bars tend to be depositional
features consisting of mobile material. This may effect sediment
transport negatively. Is this the same structure referred to as a
bankfull bench above?
YY. Morphological Measurements
The morphological measurements provided seem to indicate that the data
provided by the USACE is incorrect. However, key parameters such as
bankfull width, depth and cross sectional area were still used for Brier
Creek. They did not provide pool to pool spacing information. I
extrapolated it from the longitudinal profiles. I got about 270 feet for
the design stream and about 220 feet for Brier Creek. Are these numbers
correct?
YY. Sediment Transport Analysis
The designer used bar data in their sediment transport analysis which
as you know is suspect in North Carolina. I calculated a compentcy for a
"largest particle" of about 65 mm. I am not certain if the numbers in
table 1 are actual numbers or calculated. Please have them clarify (i.e.
I am not familiar with D85 high or low).
YY. Reference Reach
The designer did not seem very confident in their own reference streams
and seem to imply that one was recently disturbed to the point of
rendering it inappropriate and the other is incised. Are you satisfied
with their reference streams?
1 of 2 10/25/02 12:52 PM
Little Sugar DWQ# 021681
More importantly, it is not clear how bankfull elevations were
determined for the reference or design streams. This is obviously
critical if they are designing a C or E type stream. (It would be less
critical for a Bc type stream.) Please have the applicant clearly
discuss how they determined bankfull. If they could not identify it on
their reference streams by field indicators how can the reference
streams be considered appropriate? I do not agree that back calculating
bankfull based on a 1.5 year return interval discharge is appropriate
(if that's what was done). All of the information that I have ever
received would indicate that the return interval in urban areas is
closer to a 1.1 or 1.2 year event. Also, over sizing the channel based
on anticipated build out may also be risky. The cross sections for the
riffle sections of the design stream are reminiscent of Bc type streams.
In this case, it may be better to more accurately estimate bankfull than
it would be to over estimate it since there is a slope break at the
proposed bankfull elevation.
Todd St. John, P.E.
Environmental Engineer II
DWQ
Wetlands Unit
2 of 2 10/25/02 12:52 PM
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BURY 8"
MID.) .?
EXCAVATE BANK FOR
PLACEMENT OF LOG
A
TOP OF BANK
?- TOE OF BANK
COIR LOG TOE PROTECTION
CONTINUE ON BOTH BANKS
FOR LENGTH OF.PROJECT.
PLAN VIEW
NOT 'TO SCALE
12-16" (MINIMUM) DIA. LOG PLACED IN TRENCH
WITH CENTER OF LOG AT NORMAL WATER LEVEL.
PLACEMENT TO BE DETERMINED IN-THE FIELD.'
COIR LOG INSTALLED PER MANUFACTURER'S
DIRECTIONS.
1/2 LOG 0 NORMAL WATER LEVEL
-?+---- 2"x2"x36" STAKES
SECTION A-A
COIR LOG TOE PROTECTION
NO SCALE
i
I
TOP OF BANK
12" (TYP.)
MINIMUM OVERLAP
• i
TOE OF BANK I
LOG.TOE PROTECTION
!! BEGINNING AND END OF
Y LOG TOE PROTECTION TO
BE DETERMINED IN FIELD.
r
'b PLAN VIEW
NOT TO SCALE
EXISTING GRADE .12" (MINIMUM) DIA. LOG PLACED IN TRENCH
WITH CENTER OF LOG AT NORMAL WATER LEVEL:. j
EROSION CONTROL PLACEMENT TO BE DETERMINED IN THE FIELD.
FABRIC
i
_ 3/16".0 CABLE
CABLE CLAMP
L BURY
O 8 1/2 LOG 0 NORMAL WATER LEVEL
\\// EXISTING CHANNEL BOTTOM
EXCAVATE BANK FOR \
PLACEMENT OF LOG . / \ \.
DUCKBILL ANCHORS \
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• ? 15' 4?-? 1
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4, INSTALLATION OF .NORTH AMERICAN GREEN SC 150
A (OR EQUIVALENT), ACCORDING. TO MANUFACTURER'S
SPECIFICATIONS
p
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5. TOP PROT
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1- L/? f'1N 6
. LIVE-STAKING
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AND BARE-ROOT - INSTALLATION
MATERIALS AT
TOP OF SLOPE I
BURY A MINIMUM APPROVED SPECIES OF LIVE- . i
OF 8" (TYP.) STAKES-WITH 2 LEAF SCARS
TOR NODES AVOVE GROUND
FINISHED GRADE
.
EXISTING CHANNEL'BOTiOM
L _ EROSION CONTROL MATERIAL
(AMERICAN GREEN SC150
OR EQUIVALENT) TOE. PROTECTION
r (COIR FIBER LOG)
NORMAL
WATER -LEVEL
r 1/2 LOG .0
i
PLANT SPACING BASED ON _
TYPE OF VEGETATION
D SITE CONDITIONS.
I
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NO SCALE
i

INSTALLATION
ANGLE
o / 30 .
p FOOTER BOULDERS FOOTER
LLA OR LOGS BOULDER
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IMPERMEABLE CLAY
A ROCK TOE PROTECTION
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L* A
PLAN VIEW
NOT TO SCALE
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POOL
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SC150 OR EQUIVALENT) AND VEGETATIVE
COVER
FINISHED GRADE
BANKFULL ELEVATION
----------------------------------- ------------
SLOPED TOWARD CENTER
OF CHANNEL
NORMAL WATER LEVEL
0
ROCK VANE
ROCK DIAMETER:
3 FEET
30-50% OF
CHANNEL WIDTH
SECTION A-A
ROCK VANE
EXISTING CHANNEL BOTTOM

¦
AND
TABLE OF CONTENTS,
SECTION OCT 1 5 2002 PAGE
1.0 INTRODUCTION .......................................................................................................1
W H a.T?
....1
2.0 GOALS AND OBJECTIVES ................................ .?.: a
3.0 LOCATION INFORMATION .....................................................................................2
4.0 GENERAL WATERSHED DESCRIPTION ..............................................................2
4.1 Current Land Use ................................................................................................ 2
4.2 Future Land Use ................................................................................................. 3
5.0 EXISTING STREAM CONDITIONS ......................................................................... 3
5.1 Hydrological Features ........................................................................................ 3
5.2 Soils .................................................................................................................... 3
5.3 Plant Communities ............................................................................................. 4
5.4 Protected Species ................................................................................................ 4
5.5 Stream Geometry ................................................................................................ 4
5.6 Stream Substrate ................................................................................................. 4
5.7 Constraints .......................................................................................................... 5
5.8 Storm Water ....................................................................................................... 5
6.0 REFERENCE STREAM INFORMATION ................................................................ 5
6.1 Briar Creek Reference Reach ............................................................................. 5
6.1.1 Stream Classification ............................................................................... 6
6.1.2 Dimension ................................................................................................6
6.1.3 Pattern ......................................................................................................6
6.1.4 Profile ...................................................................................................... 7
6.1.5 Plant Community ..................................................................................... 7
6.2 Long Creek Reference Reach ............................................................................. 7
6.2.1 Stream Classification ............................................................................... 8
6.2.2 Dimension ................................................................................................8
6.2.3 Pattern ......................................................................................................8
6.2.4 Profile ...................................................................................................... 8
6.2.5 Plant Community ..................................................................................... 9
6.3 USGS Gauging Data ............................................................................................. 9
09177-017-018 i October 2002
Little Sugar Creek at Freedom Park
Stream Restoration Plan
6.4 Regime Data Analysis ........................................................................................ 9
7.0 STREAM RESTORATION PLAN ............................................................................10
7.1 Restored Stream Classification ......................................................................... 11
7.2 Restored Stream Morphology ........................................................................... 11
7.3 Sediment Transport Analysis ............................................................................ 11
7.4 Stability Analysis .............................................................................................. 15
7.4.1 Velocity and Stability Analysis ............................................................. 15
7.4.2 Traction Force Criteria and Shield Curve Analysis .............................. 16
7.4.3 Bed and Bank Stability Structures ......................................................... 17
7.5 Vegetation .........................................................................................................19
7.6 Storm Water ...................................................................................................... 19
8.0 STREAM PERFORMANCE CRITERIA AND MONITORING PLAN ...............19
8.1 Substrate Monitoring ........................................................................................ 20
8.2 Vegetation .........................................................................................................20
8.3 Monitoring Schedule ........................................................................................ 20
8.4 Monitoring Methods ......................................................................................... 20
9.0 STREAM RESTORATION BENEFITS ...................................................................20
10.0 REFERENCES ............................................................................................................ 22
FIGURES
Figure 1 - Little Sugar Creek Watershed at Freedom Park ............................ Appendix A
Figure 2 - Aerial Overview, Little Sugar Creek at Freedom Park ................. Appendix A
Figure 3 - Freedom Park Soils ....................................................................... Appendix A
Figure 4 - Little Sugar Creek Longitudinal Profile ........................................ Appendix A
Figure 5 - Approximate Bedrock Locations .................................................. Appendix A
Figure 6 - Storm Water Outfall Locations ..................................................... Appendix B
Figure 7 - Briar Creek Watershed .................................................................. Appendix A
Figure 8 - Diameters and Radii of Stream for Briar Creek ............................ Appendix A
Figure 9 - Briar Creek Reference Reach Longitudinal Profile ...................... Appendix A
Figure 10 -Long Creek Watershed ...............................................................Appendix A
Figure 11 - Long Creek Cross Sections .........................................................Appendix A
Figure 12 - Long Creek Pattern Map Near Primm Road .............................. .Appendix A
Figure 13 - Long Creek Topographic Map Near Primm Road ..................... .Appendix A
Figure 14 - Long Creek Reference Reach, Longitudinal Profile .................. .Appendix A
Figure 15 - Discharge Rating Curve for Little Sugar Creek ......................... .Appendix A
09177-017-018 ii October 2002
Little Sugar Creek at Freedom Park
Stream Restoration Plan
Figure 16 - Discharge Rating Curve for Little Sugar Creek ................ ..........Appendix A
Figure 17 - Discharge Rating Curve for Briar Creek .......................... ...........Appendix A
Figure 18 - Discharge Rating Curve for Long Creek .......................... ...........Appendix A
Figure 19 - 1996-2001 Annual Peak Flow for Little Sugar Creek ...... ...........Appendix A
Figure 20 - 1997-2001 Annual Peak Flow for Briar Creek ................ ...........Appendix A
Figure 21- 1966-2000 Annual Peak Flow for Long Creek ................ ...........Appendix A
Figure 22 - Regime Curve Data .......................................................... ...........Appendix A

.....
Figure 23 - Bankfull Cross Sections .............................................
.....
...........Appendix A
............Appendix A
Figure 24 - Overall Site Plan ........................................................ ...Appendix A

.
Figure 25 - Planform of Little Sugar Creek .....................................
..........
.........
............Appendix A

................
Figure 26 -Riffle Type ......................................
Figure 27 - Inner Berm and Point Bar Channel Constrictor Schemat
ic ......... Appendix A
Figure 28 - Little Sugar Creek Proposed Longitudinal Profile .......... ............Appendix A

........
Figure 29 -Interpolation Curves for Freedom Park ..................
............Appendix A

..........................
Figure 30 -Sediment Transport .............................
i
.......following p. 18
following Figure 30
ng ...............
Figure 31- Estimated Velocities and Bed Material Siz following Figure 31

............................
Figure 32 -Bank Stability Analysis ......................
following Figure 32
Figure 33 - Shield Curve Analysis ....................................................
TABLES
Table 1- Preliminary Estimates of Fluvial Morphologic Parameters ............ Appendix A
..............................Appendix A
Table 2 -Briar Creek Vegetation .....................................
Table 3 - Long Creek Vegetation ...................................................................Appendix A
.....................Appendix A
Table 4 -Bed Shear Stress Estimates .......................................
Table 5 - Estimated Bed Traction Force and Minimum D50 for Stability ....Appendix A
Table 6 - Freedom Park Potential Planting List .............................................Appendix A
APPENDICES
A Figures and Tables
B Survey of Storm Water Outfalls
October 2002
09177-017-018 ui
Little Sugar Creek at Freedom Park
Stream Restoration Plan
Little Sugar Creek at Freedom Park
Stream Restoration Plan
Mecklenburg County, North Carolina
1.0 INTRODUCTION
HDR Engineering, Inc. of the Carolinas (HDR) and Habitat Assessment and Restoration Program
(HARP) have prepared this stream restoration plan (Plan) of Little Sugar Creek at Freedom Park,
Charlotte, for the intended use of the North Carolina Department of Environment and Natural Resources
(NCDENR) Wetland Restoration Program (WRP).
The development of a restoration design for the approximately 4,200 linear feet (LF) of Little Sugar
Creek in Freedom Park entailed a multifaceted study of the historical and current stream conditions within
both the Little Sugar Creek watershed and two local reference reach watersheds. Historical human
activities, including development within the watershed and physical alteration of the stream channel, have
led to the current desire to restore the stream to more of a natural state. However, the urban environment
of the Little Sugar Creek watershed prohibits any restoration to completely natural conditions.
Constraints including development, infill in the floodplain, and large volumes of storm water runoff from
impervious surfaces restrict the number of applicable restoration options.
In most urban streams and creeks, restoration to pristine conditions is an unrealistic goal due to the extent
of prior watershed alteration. It has been documented that degradation of stream quality occurs at
relatively low levels (10 to 20 percent) of imperviousness; and at watershed imperviousness levels above
30 percent, predevelopment channel stability and biodiversity cannot be fully maintained, even when Best
Management Practices (BMPs) or retrofits are fully applied. The restoration objectives in urban streams
should then be set to target realistically attainable conditions. For the reach of interest along Little Sugar
Creek, this translates to reduction of bank erosion and partial restoration of aquatic and riparian habitat.
This report documents the attainable goals and objectives of restoring Little Sugar Creek within the
Project Area and presents an implementation strategy. Plans are based on Rosgen stream restoration
principles and reference reach analysis. In addition, a monitoring plan and schedule ensure the long-term
stability and success of this restoration effort.
2.0 GOALS AND OBJECTIVES
The goal of the Plan is to restore the stream ecosystem within the boundaries of Freedom Park.
Restoration to pristine conditions is an unrealistic goal due to the extent of prior watershed alteration;
therefore, restoration plans are based on the best available options to restore the natural functions of Little
Sugar Creek. Specific objectives of the Plan include the following: (1) water quality improvement, (2)
restoration of aquatic habitat, (3) re-establishment of native vegetation, (4) flood volume storage, (5)
reduction of bank erosion, and (6) improvement of stream corridor aesthetics. Discussion of the plans to
accomplish these objectives is included in Section 7.0. After project completion, monitoring will be
conducted to ensure the objectives of the Plan are met and the project is successful.
Actions by other local agencies will also contribute to the overall goal of restoring natural stream
functions to Little Sugar Creek. The Mecklenburg County Parks and Recreation Department is
concurrently planning the establishment of a greenway along the length of Little Sugar Creek.
Construction is slated for completion in 2003. Coordination with this and other local agencies during the
planning and construction of this project will accomplish the overall goal of providing the community
with open space and natural recreation areas. Additionally, efforts by Mecklenburg County (County) and
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the City of Charlotte (City) to implement storm water improvement strategies in the upper Little Sugar
Creek watershed will improve water quality.
3.0 LOCATION INFORMATION
The Project Area is located on Little Sugar Creek in the Catawba River Basin (HU No. 03050103) in
Mecklenburg County, North Carolina (Figure 1). The Project Area for this site is the stream reach
bounded by East Boulevard and Princeton Avenue (Figure 2) and lies entirely within Freedom Park and
the City of Charlotte. Freedom Park is a part of the Mecklenburg County Park and Recreation
Department public park system.
The North Carolina Division of Water Quality (NCDWQ) lists Little Sugar Creek in Subbasin No. 03-08-
34 and classifies the best usage of this 303(d)-listed stream as Class C. Class C waters are those protected
for secondary recreation, fishing, wildlife, fish and aquatic life propagation and survival, agriculture, and
other uses suitable for Class C. Secondary recreation includes wading, boating, and other uses involving
human body contact with water where such activities take place in an infrequent, unorganized or
incidental manner. There are no restrictions on watershed development activities. Wastewater discharge
and storm water management requirements are applicable (NCDWQ, 1999). The factors of water quality
concern are fecal coliform, biological impairment, and sediment pollution.
4.0 GENERAL WATERSHED DESCRIPTION
The drainage area for Little Sugar Creek at Freedom Park is approximately 12 to 14 square miles (Figure
1). This figure (a mosaic of the Charlotte East and Derita USGS Quadrangles) also illustrates the
predominant urban character of the watershed. The range in drainage area is due to the additional
drainage represented largely by Dairy Branch, a tributary that enters Little Sugar Creek within Freedom
Park. The headwaters of Little Sugar Creek begin near the interchange of Interstate I-85 and Highway
29/49 and flow south-southwest through a highly urbanized portion of the City, including the uptown
business district, to Freedom Park.
4.1 Current Land Use
While the Plan will be constructed within Freedom Park, the land use throughout the watershed is
highly urbanized and considered built-out. The watershed includes a portion of the urbanized
City within the I-277 beltway. Commercial and dense residential areas surround the uptown area
of the City. Currently, less than 15 percent of the area within the watershed is classified as
vacant. This small percentage of infill parcels is mostly located in the uppermost portions of the
watershed near Derita. Development includes floodplain encroachment by structures, which is
most noticeable in aerial photographs from the 1960s and 1970s.
Urban development correlates to a high percentage of impervious area. Land use/land cover in
the upper Little Sugar Creek watershed is approximately 15 to 20 percent high-density
commercial and industrial (75 percent impervious cover), 40 to 45 percent low-density residential
(15 to 20 percent impervious), and 30 percent forested land (0 percent impervious), with minor
water and other land use types (Vempaty, 1997). Using land cover to impervious cover
relationships developed by the United States Soil Conservation Service (USSCS, 1986), the
overall impervious cover is estimated at 38 percent (Wilkerson, et. al., 1998). The same authors
estimate the watershed runoff curve number as 78. The estimated percent impervious cover and
runoff curve numbers for the upper Little Sugar Creek watershed are the highest values for
watersheds of comparable size in the County. Because of this high degree of imperviousness, the
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watershed experiences quick response to storm runoff, which translates to rapid increases in
stream flows.
4.2 Future Land Use
Future development will be minimized because the watershed is considered built-out. Infill
development can occur on the remaining vacant parcels. As this infill development continues, a
small increase in watershed imperviousness is likely. Redevelopment of currently developed
parcels is also likely in this urbanized watershed.
5.0 EXISTING STREAM CONDITIONS
5.1 Hydrological Features
Past records indicate that multiple entities have dredged and/or channelized Little Sugar Creek,
including the 4,200 LF of stream within Freedom Park (Figure 2). Around 1917, an article
entitled "Drainage Work in Mecklenburg County," prepared by Heriot Clarkson, then chair of the
Mecklenburg County Drainage Commission, makes it clear that most, if not all, of the larger
tributaries of the Catawba River that drain the County were part of a County-wide dredging
program that occurred between 1911 and 1930. The dredging of Little Sugar Creek was
completed by 1917 to a minimum channel width of approximately 20 feet and depth of 8 feet.
Review of historical aerial photographs reveal Little Sugar Creek has had an established
alignment for at least the last 60 to 80 years. Overall, the current alignment has existed since early
part of the 1900s. In the 1920s, the main trunk sewer line along Little Sugar Creek was put in
place (per. comm. Andrew Burg), and this essentially corrected the alignment for the areas above
Tyvola Road. The aerial photographs also indicate that the creek was periodically cleared of
vegetation.
In the mid-1960s and early 1970s, the City initiated on erosion control system along the banks of
Little Sugar Creek, as it flows through Freedom Park, using a combination of grouted riprap and
concrete bank covering. The bottom of the channel was left in its "natural" condition. During
July 2002, the County removed the grouted riprap and concrete banking and temporarily
stabilized the banks with erosion control matting. Additionally, the large flood control weir
structure located approximately 450 feet upstream of Princeton Avenue was removed.
These impacts to Little Sugar Creek and its watershed influence the hydrology of the stream.
During a bankfull event, stream discharge ranges from 1,600 cubic feet per second (CFS) to an
estimate of 2,300 CFS at watershed build-out conditions. According to the nearest stream gage
maintained by the United States Geological Survey (USGS), bankfull discharge is 1,900 CFS
(Table 1). These storm events carry water at an estimated velocity of 6.3 feet per second.
5.2 Soils
According to the Mecklenburg County Soil Survey, soils within the Project Area include
Monacan and Pacolet (Figure 3). Monacan soils are deep, moderately well and somewhat poorly
drained with moderate permeability. They formed in recent alluvial sediments of the Piedmont
and Coastal Plain. Slopes are commonly less than two percent. Pacolet soils consists of very
deep, well drained, moderately permeable soils that formed in material weathered mostly from
acid crystalline rocks of the Piedmont uplands. Within the Project Area, these soils occur on
slopes ranging from 15 to 25 percent (USDA, 1979).
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5.3 Plant Communities
The composition and distribution of plant communities are reflective of topography, soils,
hydrology, and past and present land usage. In this case, the vegetation of the Project Area is
primarily determined by land use. The vegetation on the west side of the stream within Freedom
Park is urban with no natural community cover and is currently maintained by the County. On
the east side of Little Sugar Creek, a mature canopy of pine, ash, sweetgum, box elder and mixed
oaks (white and red) exists. Near the Nature Museum at the southern end of the Project Area,
vegetation includes an understory of dogwood and privet with a ground cover of honeysuckle,
English, and poison ivy.
5.4 Protected Species
A review of the North Carolina Natural Heritage Program database of rare species and unique
habitats (as of March 23, 2002) shows no occurrence of Federally protected species within one
mile (1.6 km) of the Project Area.
5.5 Stream Geometry
Little Sugar Creek within Freedom Park can be classified as a Rosgen Class C3 to C5 stream.
Class C streams are typically slightly entrenched with a moderate to high width to depth ratio
(Rosgen, 1996). Little Sugar Creek exhibits an entrenchment ratio of greater than 5 and a high
width to depth ratio of 12.5 (Table 1). More specifically, Class C3 to C5 streams exhibit a slope
ranging from 0.001 to 0.02 (Rosgen, 1996). Little Sugar Creek at Freedom Park exhibits a slope
of 0.0029, which is within this range (Figure 4). Bedrock outcroppings also influence the channel
slope and sinuosity by creating nick points (Figure 5).
However, this stream segment does not exhibit all the parameters for a Class C channel. Little
Sugar Creek at Freedom Park has been channelized and dredged; therefore, it does not have the
high sinuosity typical of Class C streams (Table 1). Additionally, the relationship between the
stream channel and floodplain has been altered by these activities. Flash flooding occurs in this
urban area. Dredging has also altered typical riffle and pool sequences.
5.6 Stream Substrate
The stream travels over several zones of bedrock and, in at least six locations within the stream
course, large outcrops of the native bedrock material can be seen in the stream channel and along
the banks. The channel bottom is comprised primarily of sand and pebbles, with several areas of
cobble riffles, a few large boulders, and native rock outcrop zones (Figure 5).
Riffle, pool, and point bar pebble counts present a quantitative characterization of streambed
material, sediment transport, and hydraulic stress. Surface particles, or pavement material, are
typically coarser than subpavement particles. These later particles are likely to be mobilized by
stream flows and velocities associated with near bankfull storm events. The riffle substrate D50
particle size is 4.8 mm, while the pool D50 is a larger 6.6 mm. The. point _bar D50, expected to be
the smallest of the three measurements, is 2.6 mm. The larger D84 sizes range from 6.4 mm in
riffles to 25.1 mm in pools (Table 1). Further substrate analysis is presented in Section 7.3.
4 October 2002
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5.7 Constraints
The stream restoration design of Little Sugar Creek has four sources of constraints that are
outside the realm of fluvial geomorphology and hydrology. These constraints are cost, a sewer
line, riparian land use, and adverse flooding impacts. The latter two impose severe limits on the
degree to which a design can strictly achieve a full restoration of Little Sugar Creek back to its
original floodplain setting.
A fifth constraint, not directly affecting the restoration design, is water quality. Little Sugar
Creek, from its source tributaries to the South Carolina state line, is an Environmental Protection
Agency (EPA) 303(d) listed Class C stream with fecal coliform, biological impairment, and
sediment pollution being the factors of concern. The restoration of aquatic habitat will be
impeded, regardless of the design, by the existing water quality problems, a solution for which
lies outside the scope of this specific effort. These degraded conditions will likely improve as
additional restoration efforts are implemented in the upper watershed and as the County and the
City move to implement additional storm water improvement strategies.
In addition, three bridges cross Little Sugar Creek within Freedom Park (Figure 2). These
structures must be protected to ensure their continued safety for pedestrians. The restoration
design considerations of dimension, pattern, and profile are limited by the location of these
structures.
5.8 Storm Water
Little Sugar Creek receives storm water from 21 locations along the stream reach within Freedom
Park (Figure 6). These outfalls play a part in both flow volume and water quality in Little Sugar
Creek. A comprehensive discussion, including recommendations and proposed actions, is
provided in Appendix B.
6.0 REFERENCE STREAM INFORMATION
Seven sites were investigated for their feasibility as possible reference reaches. Of these seven areas, only
two were found to have appropriate characteristics to merit the collection of reference reach data. These
are Long Creek, located in the northwest portions of the County, and Briar Creek, located just to the east
of Little Sugar Creek at Freedom Park.
6.1 Briar Creek Reference Reach
The reference reach on Briar Creek was chosen based on recommendations from City/County
Storm Water staff regarding the stability of the reach in the vicinity of Myers Park High School
(Figure 7). Dames and Moore (2001), on behalf of the United States Army Corps of Engineers
(USACE), previously studied the Briar Creek reference reach in order to provide a foundation for
an initial design framework for USACE restoration work along Little Sugar Creek from East
Boulevard to Tyvola Road.
This reference reach has approximately 19 square miles of drainage from lands predominant of
residential use and is directly adjacent to the upper Little Sugar Creek drainage basin (Figure 5).
Therefore, the sites have similar topography, soils, and land use characteristics. The two primary
differences between these sites are: 1) the Little Sugar Creek basin is more heavily developed by
commercial and industrial land use with more impervious cover and piped storm drains, and 2)
the Briar Creek reach behind Myers Park High School is, for most of its length, running in
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bedrock with an overall valley grade that is 0.0048 as opposed to the 0.0029 valley grade of Little
Sugar Creek in Freedom Park.
Briar Creek, near Myers Park High School, has substantial portions of both bed and banks
composed of bedrock. The rock has essentially stabilized the channel regardless of watershed
land cover changes. However, the channel is wide enough to pass the dredges used in early
1900s, so channel alteration cannot be assumed. The Clarkson drainage report specifically
mentions that Briar Creek--was dtedged,?,but did not discuss in any detail the limits of dredging
along the creek. Additionally, theireach has-a sewer line that was blasted into. the bedrock along
-the east side of Briar-:Creek. This created a bench composed of rock aggregate along the east
bank and modified the cross-section of the stream. Despite these detractors, Briar Creek has the
most similar land use/land cover and drainage area to Little Sugar Creek. As a part of design
research, additional data was collected to augment and confirm the data collected in the Dames
and Moore USACE study.
In summary, there are three detractors from using Briar Creek as a reference reach. First,
historical documents indicate- that the creek was part of the dredging program implemented
between 1913 and 1930. Second, when the sewer line was installed on the east bank, the rock
banks were broken up and a bench or berm was constructed along the east bank modifying its
cross-section, particularly below the bankfull stage. Third, the reach behind Myers Park High
School is largely a bedrock-founded reach, which would not easily adjust to any urbanization
flow regime, thus appearing stable despite changing hydrology. However, as previously
mentioned, Little Sugar Creek is unlikely to have any directly comparable reference reach in the
region; thus this data, combined with other reference reach information, needs to be collectively
considered in the development of a stable restoration design.
6.1.1 Stream Classification ,
Briar Creek, near Myers Park High School, exhibits similar characteristics of Little Sugar
Creek at Freedom Park, and therefore is classified similarly as a Class C/E3 to C/E5
stream. Class E streams have a higher width-to-depth ratio and sinuosity than Class C
streams. Class E3 to E5 streams have similar slope ranges as Class C3 to C5 streams
(Rosgen, 1996).
6.1.2 Dimension
The USACE reported cross-section area and bankfull stage information are included in
Table 1 for the purpose of completing the Rosgen-type morphologic analysis. It must be
viewed with some caution due to the disturbed nature of the east bank and the likelihood
that bedrock reaches 'are'not likely to respond rapidly to changing watershed conditions.
6.1.3 Pattern
Table 1 reports both the prior USACE data, as well as the additional data collected for
this study. Additional pattern information was gathered from the low elevation infrared
(IR) aerial photograph acquired at the onset of this project. Figures 8a and 8b show the
pattern of Briar Creek behind Myers Park High School, as well as below Runnymede
Lane where a set of more regular meanders are preserved. A series of 12 well-defined
meanders can be mapped from these photographs and used to calculate an average
meander radius of curvature of 186 feet. The meander belt width is dependent on
whether one includes, or excludes, large bends produced by bedrock ledges. Excluding
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the large bend behind Myers Park High School yields a meander belt width that ranges
from 80 to 200 feet. Including this bend takes the belt width to 520 feet. Bedrock control
on the variability of stream pattern in the North Carolina Piedmont makes statistical
averaging of this type of data of marginal usefulness. A typical value for areas without
strong bedrock control would be approximately 150 feet (e.g., below Runnymede Lane).
6.1.4 Profile
The prior USACE study on Briar Creek stated the valley grade as .0086; however a new
longitudinal profile (1,040 feet in length) yielded only .0044 for an average stream slope
(Table 1, Figure 9). From what can be gathered from the location figure in the USACE
report, the new profile is close to the reference reach cross-section area indicated in that
report. However, the new longitudinal profile (conducted by using an instream level
transit, survey tape, and stadia rod) indicates an average stream slope of 0.0044, with
riffle slopes ranging from 0.007 to 0.072. The profile included eight riffle sections, on
average 32 feet in length, with an average spacing of 98 feet. Stream sinuosity is only 1.1
along the 1,040-foot section, yielding .0048 as the valley slope (Table 1).
6.1.5 Plant Community
The plant community surrounding Briar Creek at Myers Park High School can be best
classified as Piedmont Levee Forest (Schafale and Weakley, 1990). Briar Creek has very
little active floodplain area or floodplain shelf in the channel. The stream channel is
deep enough that the terrace is not impacted as frequently by flooding. Hence, the forest
stops at the top of bank. Those species growing along the toe of slope of Briar Creek
include Yellow poplar (Liriodendron tulipifera), Red maple (Acer rubrum), and
Sweetgum (Liquidambar styraciflua) (Table 2). Because the forest has been protected in
the past, the sizes of the trees are greater than those at Long Creek.
Due to the urban location of Briar Creek, the number of exotic tree species, such as
Mimosa (Albizia julibrissin), and invasive species is high (Table 2). Invasive species
include Privet (Lonicera sinense), Amur honeysuckle (Lonicera mackii), and English ivy
(Hedera helix). Additionally, a sewer line on Briar Creek has been maintained as a cross
country/nature trial.
6.2 Long Creek Reference Reach
A second reference reach was established in the northwest portions of the County along Long
Creek. The stable and accessible segment of Long Creek used for a reference reach had a slightly
smaller drainage area than the Freedom Park reach of Little Sugar Creek, but is closer to the
drainage area of Little Sugar Creek at East Boulevard than the Briar Creek reference reach
(Figure 10). The Long Creek reference reach has dimensions smaller than 18 feet and would not
have passed the dredges used in the early 1900's dredging program. The Long Creek reach also
has a bedrock based riffle section with v-shaped valley profile that is inconsistent with the rock
removal and downcutting practices used in conjunction with the earlier dredging program.
The Long Creek watershed drains to the Catawba River in the northernmost part of Lake Wylie,
just below the dam, to Mt. Island Lake. The reference reach on Long Creek is just 1/4 mile
southeast of Gar Creek Cove on Mt. Island Lake. It can be accessed off Primm Road, along the
County or North Carolina Department of Transportation (NCDOT) access into the future 1485
corridor. The reach will eventually be partially impacted by the new outer belt. The watershed
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that drains to the reference has approximately 10 and 1/2 square miles of drainage from
predominant residential lands, but with subordinate forested and commercial/industrial tracts
(Figure 10). Approximately 1,200 feet of the reach were surveyed to define the pattern,
dimension, profile, and bed characteristics of the reach. Conventional stream assessment survey
techniques were used (Rosgen 1994) to acquire this information.
In lieu of field pebble counts, meander, point bar, and riffle substrate samples were collected for
laboratory grain size analysis, and independent armor studies were made in riffle and meander
pool areas to more accurately assess grade and cross-section influences on bed transport
characteristics in this reach. Additionally, the County 1:200 topographic maps augmented and
provided an independent verification on stream pattern and longitudinal profile.
6.2.1 Stream Classification
Long Creek can also be classified as a Rosgen Class C3 to C5 stream. Class C streams
are typically slightly entrenched with a moderate to high width-to-depth ratio (Rosgen,
1996). Long Creek is more entrenched than the other two streams, with an entrenchment
ratio of 1.2 and a high width-to-depth ratio of 13.2 (Table 1). More specifically, Class C3
to C5 streams exhibit a slope ranging from 0.001 to 0.02 (Rosgen, 1996). Long Creek
exhibits a slope of 0.0033, which is within this range.
6.2.2 Dimension
The average bankfull depth of Long Creek-is=2.8 feet, while the bankfull width is 37 feet.
This correlated to a width to depth ratio of 13.2. Long Creek exhibits an entrenchment
ratio of 1.9. This data and other morphological characteristics are presented in Table 1.
Typical stream cross sections are presented in Figure 11. ,
6.2.3 Pattern
The stream pattern of this reference reach is portrayed in Figure 12, from field surveys, as
well as in Figure 13 from the 1:200 topographic maps. The field surveys reveal some
small variation in bank structure not seen in the topographic maps, but which are
otherwise reasonably consistent. On Figure 12, the location and length of riffle zones, are
shown. The average radius of curvature for meander bends is 76 feet, which is 2.05 times
the bankfull width. The meander belt width is less than 70 feet if one focuses only on the
downstream lower gradient portions of the reference reach, but if one includes the larger
bend through the bedrock ridge, the belt width is closer to 420 feet (Table 1). The
meander wavelength on average is 362. The sinuosity for this reach is 1.39.
6.2.4 Profile
One attribute of this reference reach that made it appealing for design purposes for the
Freedom Park project is that the reach includes two gradient regimes. A bedrock-
founded riffle zone, some 160 feet in length, where the stream cuts through a bedrock
ledge is located at the upper end of this reference reach (Figure 14). Downstream from
this area, the gradient is lower and broken up into smaller riffle and meander areas. In
Freedom Park, the lower portions of the reach also have a steeper bedrock based zone,
and thus have some parallels to the variations seen in this 1,200-foot reference reach.
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Long Creek riffles varied from 22 to 162 feet in length, with a riffle-to-pool ratio of 0.58,
and an average riffle spacing of 104 feet (pool length). Long Creek exhibits a valley
grade of 0.0045 (ft/ft) and an average stream grade of 0.0033 (Figure 12). Riffle grades
are approximately 0.012. Other morphologic data for this reference reach appears in
Table 1.
6.2.5 Plant Community
The plant community surrounding Long Creek can best be classified as Piedmont Levee
Forest (Schafale and Weakley, 1990). Typical tree canopy species include Sycamore
(Platanus occidentalis) and Sweetgum (Liquidambar styraciflua). Typical subcanopy
species include Alder (Alnus serrulata), Redbud (Cercis canadensis), and Red cedar
(Juniperus virginiana) (Table 3).
Additionally, Long Creek has a shallow cross-section and there is an active floodplain
bench in places, particularly on the south side of Long Creek. This bench provides
habitat for shrubby species such as Alder (Alnus serrulata), Silky dogwood (Corpus
amomum), Silky willow (Salix sericea), Giant cane (Arundinaria gigantea), and
Spicebush (Lindera benzoin). Those species growing on the toe of the slope above the
floodplain include Yellow poplar (Liriodendron tulipifera), Black walnut (Juglans
nigra), and Red cedar (Juniperus virginiana) (Table 3). These species are most
prevalent on the north side of Long Creek.
However, past management has impacted the site, so that the forest is of lower quality
than Briar Creek, both in diversity and size of tree specimens. In comparison, there are
less exotic tree species, but not less exotic herbaceous species (Table 3).
6.3 USGS Gauging Data
There are four gaging stations near the three creeks involved in this study: 1) a station above
Freedom Park in the Medical Center, 2) a station below Freedom Park at Archdale Drive, 3) a
station above the reference reach on Briar Creek at Colony Road; and 4) a Long Creek gauging
station downstream from the reference reach off of Primm Road. The period of record for each of
these stations is relatively short, but each can be used to determine a rating curve for confirmation
of a discharge for a given cross-section area or stage, and thus used to verify bankfull discharge
values. Each has sufficient annual peak flows to determine an estimate of what the 1.5- and 2-
year storm discharges would be (Figure 15-18). These values can then be inverted with the rating
curves to determine the bankfull stage height for the stream at the gaging sections. In the case of
the Medical Center and the Colony Road stations, the watershed has a very similar drainage area
and can provide a good estimate of the bankfull cross-section and stage heights for verification
and design purposes.
The USGS data can be used to derive rating and annual peak flow probability curves (Figures 19-
21). The data on bankfull discharge is carried over into Table 1, on morphologic parameters.
6.4 Regime Data Analysis
The data included in Table 1 from Little Sugar Creek, Long Creek, and Briar Creek can be
compared to other data collected in rural and urban areas of the Piedmont of North Carolina to
determine whether or not they are internally consistent and appropriate for providing a reference
for the restoration design. As previously mentioned, a strict reference reach approach for Little
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Sugar Creek would be problematic due to project constraints and the uniqueness of its watershed
characteristics. Therefore, restoration goals for the pattern, dimension, and profile of the
restoration design are developed using this data taken in combination with empirical (USGS
gaging data) and hydrologic modeling data.
Figure 22 shows the Little Sugar Creek, Briar Creek, and Long Creek bankfull parameters on
North Carolina Piedmont Regime Data curves. Data collected by various engineers and scientists
over the last decade has been incorporated into these curves. The rural curves originate from a
diversity of areas in the North Carolina Piedmont (Harmon et. al., 1997), but the urban curves are
largely derived from data collected in the City by Wilkerson and others, 1997; or Keaton, 1999;
but integrated into a report by Doll et. al., 2000. Both the Charlotte projects were completed by
the first authors as part of Master Thesis requirements in the Department of Civil Engineering at
UNC-Charlotte. The larger urban streams in the Wilkerson et. al. study have channel dimensions
consistent with the operation of the dredging program in the early 1900s. The use of these urban
regime curves should be taken with great caution, not only because we cannot be confident they
were not dredged, but also because, bedrock-founded sections (like the Briar Creek at Myers Park
reference reach) cannot easily adjust to urban conditions on short time cycles. The reference
reach data collected from Long Creek is very consistent with the rural regime curves. The data
from the urban streams is also consistent with the urban regime data, though as stated above this
data may be biased.
7.0 STREAM RESTORATION PLAN
Fluvial geomorphic and hydrologic reference reach data are presented and discussed in light of the
proposed design. The design follows the basic procedures laid out in the Technical Guidelines for Stream
Restoration in North Carolina (2001) in that a reference reach approach is initially used to define the basic
fluvial geomorphic elements of pattern, dimension, and profile. This data is summarized in Table 1.
There are two factors that make a strict reference reach approach to the restoration problematic. First,
storm flow from piped storm drains in the older and more urbanized parts of the City has produced a
flashy storm surge in Little Sugar Creek which is unparalleled in any of the surrounding watersheds that
might be viewed as a comparable watershed for reference reach purposes. USGS data (Medical Center)
indicates that Little Sugar Creek rises faster and higher for a given storm than the adjacent Briar Creek
watershed (gage at Colony Road) with a larger drainage area. Secondly, the majority of Little Sugar
Creek was enlarged and entrenched by dredging prior to 1917, lowering the creek with respect to the
surrounding landscape. Unfortunately, these activities were followed by over 80 years of fill and
construction within the Little Sugar Creek floodway. Restoration to original conditions is currently not
reasonable, as it would require elevating the streambed by approximately 5 feet, with associated
substantial losses in conveyance and an attendant increase in flood damages within the FEMA designated
floodway.
The restoration design attached, in section, planform, and longitudinal view, can be characterized by the
morphologic parameters indicated in Table 1 (Figures 23-28). These parameters vary slightly from the
upper to lower ends of Freedom Park due to the drainage added by Dairy Branch. The primary difference
in the two areas of the design is that additional width has been added below Dairy Branch to compensate
for the increase in drainage area. In the design, it is not possible to elevate Little Sugar Creek 4 to 5 feet
to bring the bankfull stage to the current top of bank. The dredging completed in early the 1900s lowered
this reach by an estimated 4 to 6 feet. This entrenchment cannot be recovered due to encroachment
within the floodway. However, the entrenchment can be accommodated by the construction of an inner
floodplain bench at the 6- to 8-foot stage, coupled with the use of lower inner berms to constrict the lower
portions of the channel and add low flow sinuosity. This tiered channel system allows the design to yield
Rosgen or fluvial geomorphology parameters comparable to the reference reach and regime data sets.
09177-017-018 10 October 2002
Little Sugar Creek at Freedom Park
Stream Restoration Plan
Thus, in this perspective, while the design does not recover exactly back to original conditions, it recovers
a natural balance of stream morphologic characteristics.
7.1 Restored Stream Classification
Little Sugar Creek's existing classification of a Class C3 to C5 stream will not change with the
restoration efforts. This classification is similar to both reference reaches. Although specific
characteristics of the stream will be improved, such as increasing meander belt width, improving
riffle and pool sequences, and reducing bankfull estimated mean velocities, these improvements
will not change the Rosgen stream classification significantly. Constraints, including the urban
nature of the watershed, limit the amount of sinuosity that can be restored to Little Sugar Creek.
7.2 Restored Stream Morphology
The morphology for the restored stream reach of Little Sugar Creek at Freedom Park is based on
the level II Rosgen analysis presented in Table 1. This table presents the existing stream
conditions, reference reach analysis, and the proposed stream characteristics. Little Sugar Creek
is divided into upper and lower segments to compensate for the added water volume from Dairy
Branch.
Typical cross section dimensions are presented for both the upper and lower segments of Little
Sugar Creek. Downstream of Dairy Branch, the cross sectional area of the stream channel and
floodplain area is larger to compensate for the added flow. These cross sections include planned
side slope ranges (Figure 23). Sinuosity and riffle-to-pool sequences will be added to Little Sugar
Creek as part of the Plan (Figures 24 and 25a-e). The sinuosity is designed based on the
constraints of Freedom Park and floodplain conditions. Typical riffle cross-section schematics
are presented in Figures 26a-c.
The presented Plan view also includes planned instream actions (Figures 23a-e). Side slopes
range from 1.5:1 to 3:1. Planted toe revetment using boulders is necessary in the indicated areas
to prevent scour and erosion. Other details include bankfull benches created, where possible,
along inner meander bends for floodplain storage and vegetated inner berms. An inner berm and
point bar channel constrictor schematic showcases a built-in wing deflector and downstream drop
weir of cobble material sized for immobility, seeded soil sock placement, and vegetation (Figure
27). At the southern end of the Project Area, root wads and rock vanes will be used to stabilize
the meander and stream banks.
Additionally, the longitudinal profile of the stream will be altered to include riffles, pools, and
existing bedrock formations (Figure 28). These restoration plans also include interpolation
analysis of the bankfull stages of Little Sugar Creek and the reference reaches (Figure 29).
73 Sediment Transport Analysis
One goal in stream restoration work is to design a channel that is capable of maintaining its
dimension, pattern and profile over time. To that end, the channel should neither aggrade nor
degrade over time; rather it should be capable of migrating slowly across the landscape while
maintaining form and function. In other words, the channel should have attained a state of
dynamic equilibrium (or grade) where given its discharge and sediment load, the channel
maintains form and slope over time. A useful way of thinking about the concept of grade is
illustrated in Figure 30. For example, as either stream discharge or stream slope increases, the
09177-017-018 11 October 2002
Little Sugar Creek at Freedom Park
Stream Restoration Plan
stream tends to erode. Alternatively, if sediment size or sediment load increases, other
parameters being held constant, the stream tends to accumulate sediment.
In stream restoration work, it is vital to design the stream slope and sediment size so that the
stream will maintain an equilibrium state given expected discharges and sediment load. By using
sediment size data from reference reach studies, it should be possible to predict the sediment size
distribution required to maintain a channel at grade. Of first importance in such studies of
sediment size distributions is the size distribution of the armor layer. This layer protects the
underlying material from erosion and transport. Thus, the critical bed shear stresses required to
move the armored layer would control the initiation of movement and transport of the bulk of the
sediment comprising the channel floor. Once the armor layer is set in motion, the maximum
bedload transport rate for the given discharge for the stretch of channel likely will be achieved.
In order to understand the transport of sediment in streams a short discussion of water motion is
in order. When observing water flow, various types of flow behavior can be observed. The first
is steady flow where, at the point of observation, flow parameters such as mean velocity,
pressure, density and temperature of the fluid remain the same and do not change with time. If
the flow conditions change with time, then the flow is unsteady. Such behavior is exhibited
during flood events where first the stage (and mean velocity) rises and then the stage falls.
Uniform flows are those where the velocity is constant in the direction of the flow whereas non-
uniform flows exhibit a variation of velocity in the direction of the flow. Non-uniform flow can
be observed where a flow exits a pool and enters a riffle of smaller cross-sectional area.
In flowing water there are two main regimes exhibited by the flow, laminar flow and turbulent
flow. Laminar flow can be visualized by injecting a stream of dye into a slow-moving fluid. In
such slow-moving fluids one molecule of the fluid will travel behind the molecule immediately
downstream of it. In laminar flow, the viscosity of the fluid supplies the main resistance to
motion and the viscous force is transmitted from the non-moving fluid at the bed upward through
the flow. Thus, a velocity gradient occurs where velocity at the bed is zero and velocity increases
progressively above the bed.
With increased velocities of the fluid, dye tracer experiments document the transition from
laminar to turbulent flow. In turbulent flow, water molecules move in discrete packets in a wide
range of directions known as eddies. The mutual interference of the packets of water molecules
causes an increased resistance to motion known as the eddy viscosity. These eddies can originate
as slow-moving packets of water that rise from the bed in events known as bursts. As the packets
of slow-moving water rise above the bed into progressively faster-moving portions of the flow,
they interfere with the motion of water higher in the flow. The interference generates more
turbulent eddies, some of which descend toward the bed as fast-moving packets known as
sweeps. The sweep events can generate short-lived but intense bed shear stresses capable of
initiating grain motion. As flow velocities increase, the number and strength of the sweep events
increase as well. It is because of these eddy effects, that many stabilization efforts fail that use .
only average velocity determinations derived from discharge area relationships. For these
reasons, an adjustment safety factor of 1.5 is commonly employed in estimating the expected
traction forces that may operate on bank and bed materials.
Sediment is transported in streams in three ways: as dissolved load, as suspended load and as
bedload. The dissolved load has little effect on alluvial channel form that instead is more
strongly influenced by the transport and deposition of the solid sediment. The dissolved load will
not be discussed here. Suspended load comprises those sediments that are kept in motion above
the bed. They are held aloft by the turbulent eddies within the flow or by collisions with other
09177-017-018 12 October 2002
Little Sugar Creek at Freedom Park
Stream Restoration Plan
upward-moving grains. In order to remain suspended, the upward directed eddies must exceed
the settling velocities of the grains in suspension. The settling velocities are governed by the size,
density, shape and concentration of the grains. Once in motion, suspended load can be kept in
motion by relatively slow-moving flows.
Bedload comprises those solid sediments that move in contact with the bed. The contact can be
both continuous in nature as is the case in rolling or sliding, or intermittent as is the case in
saltation. In order to initiate grain motion as bedload, a critical bed shear stress needs to be
exceeded. The critical shear stress has two main components: the drag component and the lift
component. The drag component acts tangentially on the grain and it increases as the flow
velocity increases. The lift component, similar to the lift acting on an airplane wing, is also a
function of the increased velocity. As streamlines of the flow are compressed around a
protruding grain, the velocity along a streamline increases. This results in a drop in the pressure
force along that streamline as predicted by Bernoulli's equation. The resulting drop in pressure is
expressed as a lift force that aids in the initiation of motion. Once the grain rises into the flow,
the moving fluid can pass both below and above the grain, thereby diminishing the lift force.
Hence, with increased height above the bed, the lift force diminishes and the drag force becomes
more important. This helps explain the trajectory of saltating grains that typically rise steeply
from the bed and then exhibit a pathway of gradual descent downstream. The impact of the
saltating grain may dislodge additional grains that then rise upward into the flow.
In order for grain motion to initiate, the critical bed shear stress has to overcome the force of
gravity that keeps the grains on the bed. Bed shear stress calculations for Little Sugar Creek are
presented in Table 4. In addition, natural streambed material consists of particles of a wide range
of sizes and shapes that are commonly interlocked. Also, the top surface of the sediment on the
floor of a stream is commonly covered by an armor of material whose mean grain size is coarser
than the material immediately below the surface. Thus, the critical shear stress required to move
the armor has to overcome the weight force and the friction associated with the interlocking
grains. Once grain motion of the armor is initiated, the material beneath the armor (which is
typically finer grain sizes) is also subject to initiation of motion.
In natural streams, a maximum bedload transport rate can be defined for a given discharge and
sediment size distribution, and bedload transport often occurs at this full capacity (Richards,
1982). This occurs for a variety of reasons. First, the source of the bedload is restricted to the
channel bed and walls, so sediment transport is directly controlled by conditions within the
channel. Second, the movement of bedload is brief and discontinuous, in part due to the
frequency of those sweep events that exceed the critical bed shear stress, and in part because
bedload particles move at velocities that are less than 15 percent of the flow velocities. This
results in the floodwater that initiates bedload transport quickly outpacing the moving particles of
bedload resulting in the redeposition of the bedload. Third, bedload is normally less than 10% of
the total solids in transport and exhausting the supply of bedload material is not likely to occur.
And fourth, bedload transport utilizes much of the available stream energy and it is unlikely that
all of the available bedload material will be moved in a single flood event. So, once the armor
layer begins to move, and then the material beneath the armor layer is subject to moving
downstream. The distance the sediment moves downstream is governed by the size of the flood
event.
The transport rate of bedload increases with discharge until the supply of appropriate sediment is
exhausted. Extremely large discharges that occur rarely can have an important impact on channel
form. However, in the intervening period between extreme events, the channel form may be
modified by more common but less powerful discharges. According to Richards (1982, p.122-
09177-017-018 13 October 2002
Little Sugar Creek at Freedom Park
Stream Restoration Plan
123) "Bankfull discharge, which fills the channel without overtopping the banks, is an
intermediate discharge often considered a critical or dominant channel-forming event in natural
rivers", where a dominant channel-forming discharge is a single discharge which represents the
range of flows experienced by a channel and is thought to be responsible for the channel
morphology. Bankfull discharges recur every one to two years according to Wolman and
Leopold (1957). Thus, the size and amount of sediment being transported by a stream in dynamic
equilibrium is likely to be governed by the bankfull discharge.
These principles of sediment transport were included in the stream restoration design. Grain size
data is presented in Table 1 for both reference reaches and Little Sugar Creek. The samples were
collected in three discrete flow/depositional environments, so as to have an appropriate
foundation for the estimation of design parameters, and a means to verify `in regime' and
hydrologic assumptions of sediment transport. Thus, riffles, pools, and point bars environments
were each carefully sampled and analyzed for their grain distributions. In addition, armor
material was separated from substrate material to more accurately determine the maximum bed
traction forces acting in riffle and pool environments. In both reference reaches as well as Little
Sugar Creek, many riffle zones are positioned, and controlled by, bedrock ledges that impede the
vertical or lateral migration of the stream. This is a common, if not ubiquitous, feature of North
Carolina's Piedmont streams. In these areas a very coarse armor is commonly found which
exceeds the maximum sizes of grains expected to be mobilized by bankfull bed traction forces.
These armors are distinct from riffles within alluvial channels that commonly have armor that is
episodically involved in bedload transport. Underlying, and amongst, the armor paving the
bedrock ledge are finer grained pockets of sand and gravel, which as mentioned above, become
mobilized during events which destabilize the interlocking framework within the riffle zone.
The Plan uses the bedrock ledge model for riffle zones. In the design of these bedrock-analog
riffles, a separation of armor and substrate sizes is needed to carefully balance that portion of the
stream bed which is intended to mimic the bedrock (and its armor of large lag stones) and that
which represents components in bedload transport. The sizing for the lag stones is extrapolated
from both reference reach data sets as well as verified by calculations of maximum channel bed
traction forces (discussed further below). As mentioned above, a stream that is in morphologic
equilibrium typically achieves its maximum bedload transport rate during a bankfull event. Since
the riffle areas of Freedom Park represent less than 30 percent of the channel bed, having
substrates that can mobilize, and are features that mimic conditions found in the reference reach,
no significant impacts are expected on the channel's ability to transport sediment or dissipate
stream energy in the restoration reach. The remainder of the channel bed is to be lined with
gravel that most appropriately matches existing materials in bedload transport within the Little
Sugar Creek watershed.
Because of the highly urbanized nature of Little Sugar Creek watershed, the upper source
tributaries of Little Sugar Creek may be undergoing adjustments. These adjustments may cause
future bedload transport of materials into the restoration reach to temporarily exceed the transport
out of the reach (or vice-versa). This is in part due to the fact that bedload moves much slower
than the peak storm surge and large accumulations of sediment derived from instabilities in the
upper watershed can only move so far in a given storm. The Plan must anticipate periods when
the reach will store variable amounts of bedload sediment. These periods may be easily
misinterpreted as indications of channel instability due to observations in the short term of
aggrading (or degrading) channel conditions, whereas, in actuality, they represent snapshots of a
moving wave of sediment in the stream system, much like a sand dune moving across the Sahara
Desert. Long term monitoring (over several bankfull events) is needed to distinguish
evolutionary from episodic trends in channel sedimentation and erosion, particularly in reaches
09177-017-018 14 October 2002
Little Sugar Creek at Freedom Park
Stream Restoration Plan
that may be undergoing some adjustments to changing watershed conditions. One attribute of the
urban runoff from the upstream city center area of Charlotte is that much of the runoff is piped
directly from building roof tops and asphalt parking lots, and as such, is relative poor in bed load
sediment (not including suspended load components). This runoff reaches the main stem of Little
Sugar Creek with very little in the way of `bedload' material. This runoff then has a large
potential to entrain bedload and move it down stream. For these reasons, the restoration reach
may experience a pattern of decline in bed materials as it reaches equilibrium with the low
volumes of input bed loads, which could then lead to potential down cutting along the restoration
reach. The existence of bedrock along the reach, and the use of artificial bedrock riffle zones
(which are sized for immobility) will thus provide important protection of the channel bed.
7.4 Stability Analysis
There are five approaches to the analysis of stability for this restoration. First, the reference reach
is the foundation for the design's pattern, dimension, and profile. This paradigm assumes that
nature finds a stable design for any given watershed setting, provided there is sufficient time for
adaptation and evolution. This design model assumes that nature will find comparable fluvial
morphologies for comparable sets of watershed characteristics (topography, climate, soils,
bedrock, land use, etc.). Thus, one check on the stability of a design is that it has similar
characteristics to those observed in the selected reference reach areas.
A corollary to this reference reach model is the regime approach. The regime approach states
that, at a regional level, there are some central tendencies in streams of similar morphologic class
(e.g., Rosgen E or C-type streams) to have comparable morphologic parameters for similar
drainage areas. The regime approach has the benefit of averaging out a lot of `noise' that occurs
in individual watersheds (e.g., disruption of normal tendency by odd events or features; e.g.
hurricane, downed tree, small pond, etc.). However, neither the reference reach nor regime
approach is necessarily sufficient to achieve a stable design. Both sets of data are susceptible to
yielding guidelines that may be erroneous for a given circumstance. Thus, independent of the
reference reach or regime data, a separate effort must be made to check or verify the stability of
the restoration design.
The second and third methods used here for stability analysis are the determinations of transport
thresholds for bank and in-stream materials. These checks on transport, or erosion potential, for
bed and bank materials are either a minimum velocity analysis or critical traction force analysis.
There are two approaches for checking velocity thresholds for the design at Freedom Park, and
two approaches for the critical traction force analysis.
Lastly, stability can be looked at from a structural viewpoint. Structures can be placed or found
(e.g., the stream can be located over or within bedrock) to provide added stability. These
structural approaches are usually folded into a given project as a design unfolds and areas of
greater risk, or opportunity, are discovered.
7.4.1 Velocity and Stability Analysis
In 1994 the USACE published a graph of allowable velocity-depth data for granular
materials ranging in size from 0.1 to 500 mm. Velocity estimates for eight cross-sections
in the design for Freedom Park, and for 1.5-, 2-, 10-, and 100-year storms are shown in
Figure 31. The range of expected velocities extends from 3.5 to 8.2 fps, with water
depths ranging from 7 to 18 feet. For any given cross-section, there is a positive
correlation of velocity with depth. The expected ranges in velocities are plotted in Figure
09177-017-018 15 October 2002
Little Sugar Creek at Freedom Park
Stream Restoration Plan
31 to determine the range of sizes of granular materials that would be unstable as exposed
non-cohesive materials along the channel (this is the shaded area shown in Figure 31).
From this analysis, it is clear that materials with D50s less than 70 to 100 mm will be
unstable. In the restoration plan there are limited zones where incohesive geomaterials
will be installed with the expectation that they will not be displaced by expected storm
flows. There are five bridges along the restoration reach, and a sewer line runs the
entirety of the reach along the west side. This infrastructure constrains the design to a
non-deformable restoration pattern, dimension, and profile and requires that the banks be
engineered for little if any adjustments to flows over time. Secondly, velocity estimates
can be expected to exceed 12-14 fps when eddy effects are included in the calculations of
expected velocities (average velocities from HEC-RAS). These velocities are over or
very close to the threshold velocities for many bioengineered bank treatments (Chen and
Cotton, 1988, Parsons, D. A., 1963, Theisen, 1992, Fischenich, 2001). For these reasons,
a limited amount of boulder toe material has been used along the toe of the slope in
conjunction with the coir fiber logs to further inhibit bank failure. This zone of boulder
toe revetment is also needed to provide adequate footing for the coir fiber logs, as gravel
substrate in the channel is to be sized for mobility, and could mobilize before plant roots
have had a chance to tie coir fiber logs into banks and bed.
There is one zone above the confluence with Dairy Branch that has FEMA impacts that
cannot be readily resolved with a full bioengineered bank slope. Manning coefficients
less than 0:045`* needed-in=this zone to eliminate adverse flooding impacts. The only
vegetated treatments with appropriate Manning coefficients would be grass or very sparse
(light) low lying woodly vegetation. The former cannot be expected to withstand
velocity or bed traction forces, and the latter, has insufficient density to provide bank
support without additional hard materials. For this zone (which is approximated at 300
-feet-in length), planted boulder armor on the banks may be necessary to provide both
protection and the required flow conveyance.
In 1977 the USDA published guidelines for basic velocities for erosion and mobilization
of non-cohesive bank materials along drainage channels as a function of grain size for
both sediment-laden water and sediment-free water. Figure 32 shows the graph (as
reprinted in USACE, 1994) that is commonly used in the stability analysis. In this figure,
the expected ranges in velocity for Little Sugar Creek for the 1.5-, 2-, 10-, and 100-year
storms are shown. The minimum (3.5 fps) and maximum (8.2 fps) flows, together with
the curves for sediment-free and sediment-laden water, limit the field of potential
threshold velocities for grains of differing sizes. From this analysis, it can be concluded
that cobbles up to 4 inches in diameter are unstable as non-cohesive bank materials. Also,
in Figure 32, Table 5-1 from the USACE manual on Channel Stabilization (1994) is
shown with the 8.2 fps limit overlaid to illustrate that even soft rock formations are
transitionally unstable at the expected upper velocities. From this table, the only truly
stable banks of earth materials would be igneous or hard metamorphic rocks.
7.4.2 Traction Force Criteria and Shield Curve Analysis
Newbury and Gabory's (1993) Traction Force Criteria and Shield Curve Analysis shows
that, for streams with non-cohesive bed materials greater than 1 cm in diameter (fine
gravel), a general rule of thumb for stability may be approximated as:
Tractive Force (kg/m^2) = incipient diameter (cm);
09177-017-018 16 October 2002
Little Sugar Creek at Freedom Park
Stream Restoration Plan
This indicates that there is an empirical relationship arising from a compilation of in
transport streambed materials and tractive force observations for a wide range of channels
worldwide. The Newbury and Gaboury criteria are derived from compilations presented
by Lane (1955) and Magalhaes and Chau, (1983). These critical traction forces versus
grain size analyses and curves are sometimes referred to as Shield Curves. Table 2
includes calculations of the bed traction force derived using the formula:
Tau (kg/m^2) = 1000 x (depth (m)) x (slope (ft/ft))
This relationship is roughly equivalent to the Tau = RS formulation used by Rosgen
(1994) but can yield more accurate estimations of the maximum traction forces needed
for stability analysis, as a maximum depth can be used in lieu of the hydraulic radius.
We are more concerned with the maximum conditions that may exceed thresholds and
trigger failure in the channel system, just as a mechanical engineer would be interested in
the maximum shear stress conditions for mechanical failure. Thus, the DS rather than RS
method is used here to calculate critical traction forces.
Figure 33 shows a variation of a "Shield Curve" with data from Leopold (1964) upon
which the minimum and maximum traction forces for eight cross-sections at Freedom
Park are shown. These were calculated from the maximum depth and velocity estimates
made by the hydraulic modeling for the 1.5-, 2-, 10-, and 100-year storms.
These critical traction force calculations indicate that the bed will need to have an.
armored with material with D50s ranging from 10 to 70 cm in riffle areas to ensure
stability. The lower range is sufficient for meander areas with lower stream gradients,
but the higher estimates are needed for riffle areas with gradients upwards of 0.014.
7.4.3 Bed and Bank Stability Structures
The attached plans, cross-sections, and longitudinal profiles show the location of
structures present in the design to assist in the stabilization of the restored channel
(Figures 23-28).
With respect to bed stability, the Little Sugar Creek reach at Freedom Park contains
numerous bedrock nick points that have been carefully considered in the preparation of
the new channel's alignment (Figure 5). The new alignment intersects in a sufficient
number of the riffle sections to provide distributed grade control along the 4,000+ feet of
this restoration. Thus, no artificial grade control is needed in this design.
Secondly, hydrologic analysis indicates that only light shrubbery can be used along the
banks for approximately 3-00.-feet, upstream from the confluence with Dairy Branch so
that the Manning Coefficient can be kept close to 0.0045. If heavy shrubbery is used,
there will be unacceptable negative impacts on flooding due to the higher roughness.
Since light shrubbery would result in some exposure of the underlying non-cohesive bank
materials along this reach (alluvial soils were discovered in the excavation below the
Nature Museum), the light shrubbery must be mixed with materials that can resist erosion
and transport. Thus, the design here will be to use appropriately sized boulders along the
banks (probably large rounded cobbles and boulders along the toe, for aesthetic purposes,
and angular riprap higher for greater stability on slopes with a higher angle of repose).
09177-017-018 17 October 2002
Little Sugar Creek at Freedom Park
Stream Restoration Plan
Stream banks up- and downstream of the three bridge crossings will require stabilization
to limit erosive forces on the bridge supports and ensure safety. Recommendations
include placing armor along 50 feet of-the_ stream banks above and below each bridge:,
This armor will be planted, and should offer similar ecological function to the other bank
areas. Protection is not necessary in those areas with exposed bedrock.
Riffles and pools will also need to be sized using the above critical traction force
estimates (Table 5). The estimates for D50 and D84 for riffle and pool armor are noted in
Table 1. Riffles are designed to create shallow areas with aquatic habitat as well as back
up water to form pools. Detail riffle cross sections are presented in Figures 23a-b. In
addition, inner berms will be designed to allow sediment deposition and transport while
maintaining their stability in terms of dimension, pattern, and profile (Figure 27). The
inner berms constrict that portion of the channel below the bankfull stage to appropriate
dimensions for an `in regime' channel, yet permit higher storm flows to pass along the
reach without impacting negatively the expected flood stage heights. The leading edges
of the berms act as hard structural flow deflectors, and are sized for immobility for these
reasons. The down stream tail of the inner berms are also armored due to the expected
high hydraulic shear stresses as flow is forced to drop back down and converge at the
down stream end of each inner berm (as outlined by Haltiner, Kondolf, and Williams,
1996).
Riffles in this design act also as bedrock ledges, thus can be viewed as multipurpose
structures that provide habitat, water quality benefits, and grade control. The riffle crest
is to be slightly `v' shaped in cross section to inhibit "outflanking" and sized to resist bed
traction forces expected from a top-of-bank flow event. The sizes of riffle armor
decrease down stream. Schematics of the riffles are shown in Figure 26a-c.
09177-017-018 18 October 2002
Little Sugar Creek at Freedom Park
Stream Restoration Plan
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i l_l_ Figure 31: Estimated Velocities and Bed August 2002
HDR Engineering, Inc. Material Sizing
of the Carolinas
HA-AT Stream Restoration Plan
A<SESSMENT ANp
RESLOli A 1'9N ?- Project: 09177-017-018
PRAM = = Little Sugar Creek at Freedom Park
Freedom Park Velocities (1.5, 2, 10, and 100 yr storms)
Table 6-1
Example of Simple Allowable Velocity Data
(From EM 1110-2-1601)
Mean Channel
Channel Material Velocity, fps
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Earth
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Bermuda Grass
Sandy Silt 6,0
Silt Clay 8.0
Kentucky Blue
Unstable
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Silt Clay 7.0
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Soft Sandstone 8.0
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Figure showing the estimated velocities for the Freedom Park reach of Little Sugar Creek for
the 1. 5, 2, 10, and 100 year storms. The base table and graph are originally from USDA 1977, but
LL?? reprinted in USACOE, 1994 manual on Stream Stabilization.
lvR Figure 32: Bank Stability Analysis August 2002
HDR Engineering, Inc. Stream Restoration Plan
of the Carolinas
"?n"_
ASSESS(.tEN° ANC
Little Sugar Creek at Freedom Park
Project: 09177-017-018
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HDR Engineering, Inc.
of the Carolinas
HABITAT
AssESSMENT AND
Res ?oaAr:oN
P-RAM
Figure 33: Shield Curve Analysis
Stream Restoration Plan
Little Sugar Creek at Freedom Park
August 2002
Project: 09177-017-018
7.5 Vegetation
Following construction, vegetation will be planted along the banks of Little Sugar Creek. Plants
were chosen based on five factors: exposure, position on the slope, root structure, size, and native
species versus introduced species. These species will be planted along three areas of the stream
bank: the toe, midslope, and top of slope. The estimated number of plants is over 40,000. This
number, as well as the mix of species planted, will be refined as construction plans continue.
In preparation for the planting effort, native plant material has already been collected, rooted and
stored. Approximately 30,000 specimens have been treated in this manner. The major benefit to
having plants in this form will be that the root system is already well established which will lead
to quicker stabilization and better shade growth. The remainder of the plantings will occur as
traditional live staking or some other industry standard bioengineering planting techniques.
Typical native species chosen for Freedom Park include Blueberry (Vaccinium spp.), Button bush
(Cephalanthus occidentalis), Elderberry (Sambucus canadensis), Silky dogwood (Cornus
amomum), and Smooth hydrangea (Hydrangea arborescens). In addition, some exotic species
are also planned including Glossy Abelia (Abelia grandiflora) and Shrubby St Johnswort
(Hypericum prolificum) (Table 6).
Vegetation choices are limited by the site conditions. As previously mentioned in Section 7.4.3,
plants must be able to withstand the high velocity flows and water forces in Little Sugar Creek as
well as not reduce the conveyance abilities of the stream during storm events. In addition, soil
conditions and bedrock outcroppings shape planting plans.
7.6 Storm Water
Stream restoration of Little Sugar Creek within Freedom Park will restore pattern, dimension, and
profile to the stream. These alterations from existing conditions necessitate the relocation of
storm water drainage outfalls within the Project Area. A comprehensive discussion of
recommendations and proposed actions for those storm water outfalls is presented in Appendix B.
Eleven storm water drainage areas are impacted by the Plan. Where feasible, recommended
improvements promote infiltration of storm water and reduce pollutant loading to Little Sugar
Creek. In addition, these outfalls must be protected from erosive forces. These recommended
actions consider budget and Project Area constraints.
8.0 STREAM PERFORMANCE CRITERIA AND MONITORING PLAN
Restoration of Little Sugar Creek in Freedom Park will be determined a success after the monitoring
period is complete. The stream channels should maintain their dimension, pattern, and profile over time.
Additionally, instream structures should remain secure and stable during the monitoring period.
It is expected that there will be some minimal changes in the cross-sections, profile, and/or substrate
composition. Changes that may occur during the monitoring period will be evaluated to determine if they
represent a movement toward a more unstable condition (e.g., downcutting, deposition, and/or erosion) or
if they are minor changes that represent an increase in stability (e.g., settling, vegetative changes, and/or
decrease in width-to-depth ratio). Unstable conditions that require remediation will indicate failure of
restoration activities.
09177-017-018 19 October 2002
Little Sugar Creek at Freedom Park
Stream Restoration Plan
8.1 Substrate Monitoring
A Modified Wolman Pebble Count (Rosgen, 1996) provides a quantitative characterization of
streambed material. This composition information is used as an indicator of changes in stream
character, channel form, hydraulics, erosion rates, and sediment supply. Pebble count data can be
used to interpret the movement of materials in the stream channels. Established D50 and D84
sizes should increase in coarseness in riffles and increase in fineness in pools. Data collected
over the monitoring period should be plotted over that of the previous year(s) for comparison.
Over time, established D50 and D84 should be compared.
8.2 Vegetation
Native vegetation, as determined by reference reach vegetation inventories, will be planted.
Survival of vegetation within the riparian buffer will be evaluated using survival plots. Survival
of live stakes will be evaluated along the stream corridor of the restoration site. Vegetation
survival of target dominant species will be confirmed. Woody vegetation will be monitored for
five years, or for two bankfull events. Plants should be replaced per the contract documents.
8.3 Monitoring Schedule
Annual monitoring is required for a five-year period beginning in 2003 and ending in 2007.
Reports will be submitted in 2003, 2005, and 2007 to the USACE and the NCDWQ Wetland
Restoration Program.
8.4 Monitoring Methods
Monitoring at established locations will ensure consistency and allow comparison of data over
time. Permanent cross-sections will be established in Little Sugar Creek. Cross-section changes
can indicate changes in the width-to-depth ratio of the stream. Bank slopes should remain stable.
Comparison of longitudinal profiles during the monitoring period will indicate excessive changes
over time. Monitoring at these locations, as well as established vegetation plots and pebble count
locations, will ensure consistency and allow comparison of data over time.
9.0 STREAM RESTORATION BENEFITS
As previously discussed, Little Sugar Creek is an EPA 303(d) listed stream with fecal coliform
contamination, biological impairment, and sediment pollution being the factors of concern. Water quality
within Freedom Park is influenced by upstream land use activities, lack of habitat, poor mature tree cover
and stream bank erosion. While this plan does not address stream conditions outside of Freedom Park,
there are significant benefits that will occur due to the project.
Improvements will occur with the addition of a vegetated stream buffer zone. These buffers provide three
main benefits. The buffers will filter runoff before it enters the stream, which will remove pollutants and
promote infiltration. The buffers will also shade the stream, lowering stream water temperatures, and
reducing the algae blooms that occur during the summer months. These buffers also provide terrestrial
habitat for small mammals and birds. As additional restoration efforts are implemented in the upper
watershed, including storm water improvements, the degraded water quality conditions will continue to
improve.
Aquatic habitat improvements for this project include the creation of riffle and pool sequences within the
channel, as well as rock and log structures. These variations in habitat will provide shelter and feeding
09177-017-018 20 October 2002
Little Sugar Creek at Freedom Park
Stream Restoration Plan
opportunities for aquatic organisms and provide for a wider array of habitat locations, thus increasing
aquatic community diversity.
The Plan will restore sinuosity to Little Sugar Creek within Freedom Park. This improvement in pattern
will reduce erosive stream velocities. Dissipated stream energy will also have positive effects
downstream by the reduction of velocity and ultimately sediment inputs. Added sinuosity will also
increase the amount of aquatic habitat available since the stream will be longer as compared to the pre-
project length.
Opportunities for storm water improvements will also improve water quality and reduce volume
contributions to the stream. Improving storm water outfall structures and their locations, thermal spikes
can be avoided or minimized, pollution can be filtered out of storm water and infiltration can be
encouraged. The Freedom Park pond also has an overflow structure that currently discharges directly into
Little Sugar Creek. This outfall is a heavy source of fecal coliform contamination and the Restoration
Plan will help to begin addressing this water quality concern.
Additionally, there is an excellent opportunity for environmental education associated with this
restoration effort. The Charlotte Nature Museum is located near the east bank of Little Sugar Creek
within the Freedom Park property. This environmental education center conducts workshops and camps
for children and is open to visitors. Educational efforts will include the need for water quality and aquatic
habitat improvements in Little Sugar Creek and urban streams in general. The riparian area adjacent to
the Nature Center and the restored stream provides the opportunity to address the functions and benefits
of native vegetation and riparian areas.
09177-017-018 21 October 2002
Little Sugar Creek at Freedom Park
Stream Restoration Plan
10.0 REFERENCES
CH2MHill, 2002, Charlotte Area Local Watershed Plan Task 1: Data Collection, Subwatershed
Delineation, Historical Context Review and Indicators Establishment for the NC WRP.
Charlotte-Mecklenburg SWIM Stream Buffers. Accessed October 25, 2001.
http://www.charmeck.nc.us/ciengr/land/text.htm#SurfaceWaterlmprovementand Management.
Clarkson, Hariot, 1917(?) Drainage in Mecklenburg County. Source unidentified, appended to CH2Mhill
(2002) report above.
Dames and Moore-NC, 2001, Final Little Sugar Creek Geomorphic Analysis, USACE, Wilmington
Office, North Carolina.
Doll, Barbara, Wise-Frederick, D.E., Buckner, C.M., Wilkerson, S.D., Harmon, W.A., Smith, R.E. 2000.
Hydraulic Geometry Relationships for Urban Streams throughout the Piedmont of North Carolina, in
NCSU Course Notes: N. C. Stream Restoration Institute, River Course, Raleigh, NC.
Harmon, et al. 1999. Bankfull Hydraulic Geometry Relationships for North Carolina Streams. In:
AWRA Wildland Hydrology Proceedings. D.S. Olsen and J. P. Potyondy eds., AWRA Summer
Symposium, Bozeman, Mt, pp. 401-408.
Keaton, Jeffrey. 1998. Development and Analysis of Hydraulic Geometry Relationships for the Urban
Piedmont of North Carolina, Final Rpt., Year 1, Charlotte Storm Water Services.
Lane, E.W., 1955. Design of Stable Channels, American Society of Civil Engineers Trans., v. 120 p.
1234-1279.
Leopold, L.B., Wohman, M.G., and Miller, J.P. 1964. Fluvial Processes in Geomorphology, W.H.
Freeman and Sons, San Francisco, CA.
Magalhaes, L. and Chau, T.S., 1983. Initiation of motion conditions for shale sediments, Canadian
Journal of Civil Engineering, v. 10, p. 549-554.
Mecklenburg County Park and Recreation Department. 1999. Mecklenburg County Greenway Master
Plan, Charlotte, NC.
Newbury, R. W., and Garoury, M. N., 1993. Stream Analysis and Fish Habitat Design, A field Manual,
Newbury Hydraulics, Gibsons, British Columbia, Canada, 262 p.
North Carolina Department of Environment and Natural Resources. 1999. Catawba River
Basinwide Water Quality Plan. Division of Water Quality. Raleigh, NC.
2000. 2000 303(d) List (Final Draft). http://h2o.enr.state.nc.us/mtu/download.html.
2001. 2001 Draft Internal Technical Guide for Stream Work in North Carolina, ver. 2. Division of
Water Quality, Raleigh, NC.
. 2002. Natural Heritage Element Occurrences. Division of Parks and Recreation, Natural Heritage
Program, Raleigh, NC.
09177-017-018 22 October 2002
Little Sugar Creek at Freedom Park
Stream Restoration Plan
North Carolina Division of Land Resources and North Carolina Division of Water Quality. 2000. "Draft
Internal Technical Guide for Stream Work in North Carolina."
Radford, A.E., H.E. Ahles, and C.R. Bell. 1968. Manual of the Vascular Flora of the Carolinas.
University of North Carolina Press, Chapel Hill, NC.
Richards, Keith. 1982. Rivers, Form and Process in Alluvial Channels. Methuen, London and New York,
358 p.
Rosgen, D.L. 1994. A Classification of Natural Rivers, Catena 22 (1994): 169-199.
Rosgen, D.L.1997. A Geomorphological Approach to Restoration of Incised Rivers, Proceedings of the
Conference on Management of Landscapes Disturbed by Channel Incision.
Rosgen, D.L. 1996. Applied River Morphology. Wildland Hydrology Books, Pagosa Springs, CO.
Schafale, Michael P. and Alan S. Weakley. 1990. Classification of the Natural Communities of
North Carolina - Third Approximation. North Carolina Natural Heritage Program. Raleigh, NC.
United States Army Corps of Engineers. 1994. Channel Stability Assessment for Flood Control Projects,
EM 1110-2-1418.
United States Department of Agriculture. 1977. Design of Open Channels, Tech. Release No. 25, Soil
Conservation Service, Washington, D.C.
1980. Soil Survey of Mecklenburg County, North Carolina. Natural Resource
Conservation Service.
United States Soil Conservation Service. 1986. Urban Hydrology for Small Watersheds, Tech. Rel. 55
(2nd ed.).
Vempaty, Ganesh. 1997. Relationship between water quality and Landuse in the Sugar Creek
Watershed, N.C. Master Thesis Dissertation, Department of Civil Engineering, University of North
Carolina-Charlotte.
Wilkerson, Shawn, Karl Lindin, James Brown, and Craig Allan. 1998. Development and Analysis of
Hydraulic Geometry Relationships for the Urban Piedmont of North Carolina, Technical Report To
Charlotte Stormwater Services.
Wolman, M.G., and Leopold, L.B. 1957. River flood plains: some observations on their formation,
Professional Paper, United States Geological Survey, 282C, pp. 87-107.
09177-017-018 23 October 2002
Little Sugar Creek at Freedom Park
Stream Restoration Plan

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Stream Restoration Plan
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of the Carolinas
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H Stream Restoration Plan
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" Stream Restoration Plan Photography March 2002
R' rt??-it Little Sugar Creek at Freedom Park Project: 09177-017-018
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HDR Engineering Inc. Stream Restoration Plan
of the Carolinas
H.- ,:. Little Sugar Creek at Freedom Park
R fif Project. 09177-017-018
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Figure 10: Long Creek Watershed August 2002
HDR Engineering, Inc. Stream Restoration Plan
of the Carolinas
" Little Sugar Creek at Freedom Park
Project: 09177-017-018
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Figure 11: Long Creek Cross Sections August 2002
HDR Engineering, Inc. Stream Restoration Plan
of the Carolinas
H
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Project: 09177-017-018
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HDR Engineering, Inc. Stream Restoration Plan
of the Carolinas
F{,.,, °? Little Sugar Creek at Freedom Park
Project: 09177-017-018

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Figure 13: Long Creek Topographic Map Near Primm Road
August 2002
HUk Engineering, Inc. Stream Restoration Plan
of the Carolinas
H Little Sugar Creek at Freedom Park
p Project: 09177-017-018
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HER Engineering, Inc. Stream Restoration Plan
of the Carolinas
Little Sugar Creek at Freedom Park Project: 09177-017-018
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HDR Engineering, Inc. Little Sugar Creek Near Medical Center
of the Carolinas
"" °' Stream Restoration Plan
R ??- r Little Sugar Creek at Freedom Park Project: 09177-O17-0] 8
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Steam Flow
8000
Inside Gage Height - Discharge Rating Curve for Little Sugar Creek
Near Archdale Drive
(USGS Station ?? 1985 -2002)
D 2000 4000 ?00i i i;OCiri
1 10?
Steam Flow
Figure 16: Discharge Rating Curve for August 2002
HDR Engineering, Inc. Little Sugar Creek Near Archdale Drive
of the Carolinas
" Stream Restoration Plan
R .,.
R? a Little Sugar Creek at Freedom Park Project: 09177-017-018
Area - Discharge Rating Curve for Briar Creek Near Colony Road
(USGS Station 0214645022 1995 - 2002)
Flll
500
401-1
ca
a?
q
1iri
2010
10v
0
_ ................... .......... .....:...............................
. J?....
_ ..................... .......:..................................... ..................... ................ .................................................
Y = MO*X1
7707F 3.5008
M1 0.57469
R I 0.97532

0 500 1000 1500 2000
2500 30001
Stream Flow
15
Inside Gage Height - Discharge Rating Curve for Briar Creek Near Colony Road
(USGS Station 0214645022 1995 - 2002)
R= 0.93342

a? 10
a?
C7
m
rn
r
0
0 500 1000 1500 2000
Y = MO*X?''
MO1 .4568
MI 0.201 7
R I 0.93342
Stream Flow
2500 3000
f DR Figure 17: Discharge Rating Curve for August 2002
HDR Engineering, Inc. Briar Creek Near Colony Road
of the Carolinas
"" Stream Restoration Plan
R Project: 09177-017-018
?> Little Sugar Creek at Freedom Park
Area - Discharge Rating Curve for Long Cry
(USGS Station No. 02142900 1965 - 2002)
800
700
500
m
D 400
300
200
100
0
_ ................?....... 4 ... ..................`. ?........................... .......................... ......................
a . -
s'
? 3 3 3 9
Y = M0*X"M 1.7461
P 0.74588
1 R 0.93413
0 500 1000 1500 2000
Stream Flow
2500 3000 3500 4000 1
Outside Gage Height - Discharge Rating Curve for Long Creek
(USGS Station No. 02142900 1965 - 2002)
14
12
10
8
4
2
0
0 500 100 1b00 2000 2500 3000 3500 4?0
0 n
-? Stream Flow
L? Figure 18: Discharge Rating Curve for August 2002
HDR Engineering, Inc. Long Creek
of the Carolinas
A' Stream Restoration Plan
Rfi- Little Sugar Creek at Freedom Park Project: 09177-017-O18
P
r2c rr -?` Q asoo or$,
v! g a n C; s
1000a
1000
100
U
Vl
0
10
1.0 L
2
5 10 15 20 30 40 50 60 70 80 85 90 95 98
Annual Probability of Exceedence (%)
Figure 19: 1996-2001 Annual Peak Flow August 2002
HDR Engineering, Inc. for Little Sugar Creek Near Medical Drive
of the Carolinas
H.?" Stream Restoration Plan
Rc<-o n o'u "° K N- ' Project: 09177-017-018
Paocans, ..-_z Little Sugar Creek at Freedom Park
V. - ® 2 1-0a
9,sjrZV 16C%4e>;`s
10000
t
1 '
1000
100
=T7
ids .
2 5 - its 15 20 30 40 50 6D 70 80 85 9D 95 9s
Annual Probability of eoderce
J-? Figure 20: 1997-2001 Annual Peak Flow August 2002
HDR Engineering, Inc. for Briar Creek North of Colony Road
of the Carolinas
HA81TAT Stream Restoration Plan
/{<SESSMENT AND
Pro
R"'°RA fir
Little Sugar Creek at Freedom Park Project: 09177-017-018
PROGRAM :.- =- ?i-
1,%41r 7 660 4ZT-S
10000-1
P 4
10y ? r
s,.r
10
:.:
V
1
ID
1
1.0
2 5 101520 3041) 50 60 70 80 85x90 95 98
Annual P'robat lit`' of E. dorce (%.)
Figure 21: 1966-2000 Annual Peak Flow August 2002
HDR Engineering, Inc, for Long Creek Near Paw Creek
of the Carolinas
HAwAT Stream Restoration Plan
A,s-s.cW AID
RES!OtiAnON rttr _ Little Sugar Creek at Freedom Park Project: 09177-017-018
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Upper Freedom Park Riffle Section
Approx. Floodplain
Upper Freedom Park Meander Section
CONSTRAINTS BOUNDARY
I
I
Approx. Floodplain
Erosion Control Matting
Graded riffle bed (sized for stability and
0 10 20 ft
no vertical exaggeration
Cut banks back to 3:1 above bankfull stage where feasible
75.3 ft
12.0 ft (580 sq ft)
1L
Head and tail of Berm with cobbles
sized for immobility, cored by sand
and gravel, topped with sandy loam.
Inner Berm
Point Bar
8.0 ft (385 sq ft)
6.0 ft (240 sq ft).'
2
Graded pool bed (sized for mobility)
HARP Freedom Park Restoration Project, Proposed
/HDR Bankfull Cross Sections -East Blvd to Dairy BrancF?
Revised
9/30/02
I-I-F-- F-- F-
I- I- I- F--I-
I-F-I-F-- I-
T- I- I- I- I-
F-- I- I- I- F--
F--
iDR Engineering, Inc.
min Ma Wa
aw•.?u a[ n?
IG. Hunyeutt
N C Wetlands Restoration Program
Freedom Park - Little Sugar Creek
Channel Restoration
Charlotte
I? Aug. 2002
North Carolina AS NOTED
Bankfull Cross Sections
East Blvd. to Dairy Branch
A 1 8 C D E F I G H I I J K I M N 0 P
4
Lower Freedom Park Meander Section
Erosion Control Matting
Cut banks back to 3:1 above bankfull stage where feasible.
Bankfull Width
in 85.1 ft
12.0 ft 0065 sq ft) x
Inner Berm Fiber log/sock 8.0 ft (570 sq ft)
t for toe support 6.0 ft (308 sq ft) k
and planting 1
Point Bar
f 2
Lower Freedom Park Riffle Section
12.0 ft (545 sq ft)
Two stacked rows 8.0 ft (343 sq ft)
of coir fiber/biolo
1 for toe support 6.0 ft (226 sq ft) 1
2 and planting " -
:i i 4hr+•' Z
l ?:,?'t'.:n 'r...? r?dry,.,.?a,?,:_,a?
2
Grade to form Bankfull (64) Graded pool bed
inner "floodplain" terrace Head and tail of Berm with cobbles (sized for mobility)
sized for immobility, cored by sand
and gravel, topped with sandy loam.
0 10 20 ft
no vertical exaggeration
Cut banks back to 3:1 (or more) above bankfull stage where feasible
69 3 ft Approx. Floodplain
Graded riffle bed (sized for stability,
extended to depth of excavation) ,

f N C Wetland Restoration Pro
ram Bankfull Cross Sections
F_ F_ I F_ F g

F_ F_
HDR Engineering, Inc. °- ° Freedom Park - Little Sugar Creek
Dairy Branch to Princeton Ave.
f F_ f f Channel Restoration
f F_ F_ F__ ?.
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Charlotte North Carolina

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J? N C Wetlands Restoration Program Overall Site Plan
Freedom Park - Little Sugar Creek
HDR Engineering, Inc.
Channel Restoration
® mwmnsaioi Aug. 2002 09177-017-018-05
IG. Huneycutt Charlotte North Carolina Y NOT TO SCALE XXXXX.DWG Fig. FA
1
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Built-in Deflector & Drop Weir
?J for Inner Beim/Point Bars
1.5.2 :1 Riparian Bank with
coir fiber log & biolog at toe
2.3:1 Riparian Bank with
coir fiber log & biolog at toe
Anchored log wing deflector
0 50 100 ft

Type II
Figp?ure 25a: Planform of Little Sugar Creek at Freedom Park September 2002
HDR En6neeting. Inc b
H of the Carolinas Stream Restoration Plan
, .
R Little Sugar Creek Project: 09177-017-018
P
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Riffle Type 1. (cross vane riffle crest)
Moderate to steep grade (.7 - 1.4%)
without bedrock, riffle armor at crest
D50 sized for immobility, crest cross vane
material brought up bank flanks to 18",
toe of bank downstream from crest
is protected by 12" coir fiberlog
at toe with second
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HDR NC WETLANDS Freedom Park Restoration Reach Riffle Type I. Built-in cross vane
RESTORATION 2002
SEPT 27
HARP Little Sugar Creek at riffle crest immobile armor ,
PROGRAM

Figure 26a: Riffle Type I September 2002
HDR Engineering, Inc.
H of theCarohna,
. Stream Restoration plan
"„ Little Sugar Creek Project: 09177-017-018

Riffle Type II. Cross vane-riffle front with
intra-riffle pool, used for low grade inflection areas
(.3 - .7% grade)without bedrock
(Cross vane: all footer stones 1.5 x

a
mobility Shield curve limit, bank flanks of cross vane "
material brought up to 18 above mean intra-
storm flow stage, topped by 12"
diameter biolog; Cross vane tail-riffle self
KIN
A
Lr`'a j .
adjusting bed load, sized to match
~
existing D50 riffle material. ^

• • • 4

HDR NC WETLANDS Freedom Park Restoration Reach Riffle Type II, Cross vane w/self-adjusting
RESTORATION SEPT 27
2002
HARP Little Sugar Creek ? low grade tail riffle and pool ,
PROGRAM

?ee
Figure 26b: Riffle Type II
September 2002
HUR Engineering, Inc
,
of the Carolinas Stream Restoration Plan
R- .__ . fi ?`-A Little Sugar Creek Project: 09177 0» ors

Riffle Type III. Augmented bedrock nickpoint,
moderate to steep grade (.7 - 1.4%)
with limited bedrock in channel and bank toe (semi-
competent saprolite to competent gneiss or diabase).
Bedrock riffle zone enhanced with lag stones to
meet reference reach riffle:pool ratio.
Lag stones have D50 sized for immobility. :' .
•
Bank toe protected by coir fiber and '` ci::. a d• ?;
biolog combination in semi-
:
-o 0
cohesive saprolite. Exposed : da
competent rock in bank
to be left as is.
d
G? - :fie v,
Aw 4 s .

HDR NC WETLANDS Freedom Park Restoration Reach Riffle Type III. Enhanced Bedrock
RESTORATION 2002
SEPT 27
HARP Little Sugar Creek f?ickpoint Zone. ,
PROGRAM

Figure 26c: Riffle Type III September 2002
HDa En ? c, Inc.
°f`heCarolinas Stream Restoration Plan
A
P?
Little Sugar Creek Project: 09177-017-018
f.
t' Seeded Soil Sock 18
'
9 ==;and 8: Gravel Point Ear-
Down C
t t
4
1 -
Seeded Inner-Berm .?
urrep
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1j
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171 z -
ft
5 fit
HDR Engineering, Inc.
of the Carolinas
A-
P.......... .,
Stream bed
(coar:? =and)
-:
-t
Go-wrt St earn Drop 'Trier
of Gt7aded i i:,bble=
i;azed fo r immob ilitw:i
Erasion Control tvbtting
v 1 , a:
Cross Section View
Sand,( Loam Fyn d and Grave I
Figure 27: Inner Berm and Point Bar Channel Constrictor Schematic
Stream Restoration Plan
Little Sugar Creek at Freedom Park
Z; ft
UP-str earrt Deflector
Graded Cobbles
(Sized for Immobility.)
August 2002
Project: 09177-017-018

R -up- -pur1Uem or encountered conditions.
I
HDR Engineering, Inc.
of the Carolinas
H?.-.
but approximately .014 - .02
Figure 28: Little Sugar Creek Proposed Longitudinal Profile
Stream Restoration Plan
Little Sugar Creek at Freedom Park
609 ft
607
605
603
601
599
597
595 It
feet
`eto
/? q
Ve
August 2002
Project: 09177-017-018

Interpolation Curves for Freedom Park Restoration - Little Sugar Creek
m
10.0 300 %IA
ppc•r FrecYfmn Lager Freedom
Park Reach Park (teach
Lower Freedom
8.0 Park Reach 250 Upper Freedom
Park Reach
Long ('reek
Bankfull Ref. Reach I I a rl kfu II f.mig Creek
6.0
Meall Area 200 Ref. Reach Briar(leeh
Depth (sq. feet) Ref. Reach
ii
(Ieet) 4.0 Briar Creek r 15V
Ref. Reach.
I
2.0 100-
8 10 12 14 16 18 20 8 10 12 14 16 18 20
Drainage Area (sq. miles) Drainage Area (sq. miles)
L
250 ower Freedom T 90
Park Reach
Long Creek Lpper Freedom l'pper Freedom
Ref. Reach Park Reach Park (teach
200 75
Lower Freedom
Meander
Radii of 150 I Bankfull 60 Long (reef; Park Reach
N-Vidth ReL Reach
Curvature
(feet) ?_- ? (feet) 100--
45--
Briar R Creek
Rel. (teach Briar Creek
50 30 Ref. Reach
i
8 10 12 14 16 18 20 8 10 12 14 16 18 20
Drainage area (sq. miles) Drainage Area (sq. miles)
Figure 29: Interpolation Curves for Freedom Park
August 2002
HIM Engineering, Inc. Stream Restoration Plan
of the Carolinas
Little Sugar Creek at Freedom Park
R,. Project: 09177-017-018
Table 1
Prelimina Estimates of Fluvial Mor holo is Parameters
t: Parameters r _ t - Little Sugar Creek;
FreedomPark Reach Briar Creek
Reference Reach Briar Creek
Reference Reach AA Long Creek
" Prim Road Ruch Little Sugar Creek Freedom
Park Design U ,er End LittleSugar,Creek Freedom
Park Design Lower E d

Watershed Area (sq. miles) 12.38.14.21 19 19 10.9 12.38.14.21 12,38.14.21
Bankfull Width (ft) 64 49 37 51 57
Bankfull Area (sq. feet) 302 314 119 335 343
Ave. Bankfull Depth (feet) 5.1 6.41 2.8 6.5 6
Max. Depth (feet) 9 11.09 5.2 8 8
Flood Prone Width (feet) 300 >150 71.6 >300 >300
Entrenchment Ratio >>5 »2.2 1.9 >>5 >>5
Width/Depth Ratio 12.5 7.64 13.2 7.8 9.5
Valley Slope (feet/feet) 0.0029 0.0086 0.0048 0.0045 0.0029 0.0029
Average Water Slope (feet/feet) 0.0028 0.0078 0.0044 0.0033 0.0026 0.0029
Sinuosity 1.04 1.1 1.1 1.39 1.11 1.11
Riffle/Pool Ratio 0.86 0.24 0.58 0.3 0.3
Riffle Slope .006-.074 (avg, .033) .007 - .072 (avg..018) 0.012 :01- .014 .01 -.014
Pool Slope 0 -.0027 (.0009) «.002 0 - .002 <.0003 <.0003
Ave. Riffle Spacing (feet) 98 98 104 141 141
Riffle Armor D50 45 mm 165 mm 84 mm 440 mm 440 mm
Riffle Armor D84(low) 95 mm 48 mm 220 mm 220 mm
Riffle Armor D84 (high) 295 mm 150 mm 700 mm 700 mm
Riffle Substrate D50 4.8 mm 1.9 mm 1.1 mm 4.8 mm 4.8 mm
Riffle Substrate D84 6.4 mm 3.0 mm 2.6 mm 6.4 mm 6.4 mm
Pool Armor (D50) 44 inm 40 mm 40 mm
Pool Armor (D84 low) 25 mm 24 mm 24 mm
Pool Armor (D84 high) 82 mm 56 mm 56 mm
Pool D50 6.63 mm 1.9 mm .4 mm 6.63 mm 6.63 mm
Pool D84 25.1 mm 3.0 mm .8 mm 25.1 mm 25.1 mm
Point/Medial Bar D50 2.6 mm - 1.1 mm .7 mm 2.6 mm 2.6 mm
Point/Medial Bar D84 9.8 mm 2.1 mm 1.1 mm 9.8 mm 9.8 mm
Meander Radius of Curvature (ft) 94 - 200 (avg.155) 186 64.210 (avg. 109) 160.220 ft 160-220
Meander Wave Length (ft) 433.532 456.552 (avg. 515) 550 362 395 ft 395 ft
Meander Belt Width (ft) 0-125 92.150 (115) 150 200 200 ft 467 ft
Bankfull Discharge (cfs) via * or ** 1600 - 2300 (*) 2100(")
1600 2300 (*)
1600 2300 (*)
Bankfull Discharge (cfs) via A or m 1900 (A) 1600 (A) 495(-) 1900 (A) 1900 (A)
Bankfull Est. Mean Velocity (ft/sec) 6.29 6.68 4.16 5.67 5.53
Rosgen Class (***) C3-C5 C/E 3.5
I
C3 C5
C3 C5
C3 C5
4.g Z? 94?1
(`) HDR estimate at watershed buildout
(**) Army Corp. Eng. 2001 Study Estimate
(***)Rosgen & Silvey,1998, however none of the
above fit all parameters for C or E channels
(A) estimates from recorded annual peak flows at
USGS gage stations near reference reach
(^A) supplemental data collected for this study
(Am) estimated using Manning Eq.
Assuming Manning Coef. ,03
L Z5o+ U90
Table 2
Briar Creek Vegetation
Canopy
River birch Betula ni ra
Sycamore Platanus occidentalis
Yellow poplar Liriodendron tuli ifera
White oak Quercus albs
Sweet um Li uidambar st raciflua
Green ash Fraxnnus enns lvanica
Willow oak Quercus hellos
Black walnut Ju lans ni ra
Southern sugar maple Acer sacchaurm ss . floridanum
Box elder Acer ne undo
Pignut hickory Ca rya labra
Black willow Salix nigra
Subcanopy.;-
Trans ressives of the Canopy Species
Black um N ssa s lvatica
Ironwood Car inus caroliniana
Dogwood Corms florida
Pawpaw Asimina triloba
Redbud Cercis canadensis
Exotic Invasives
Mimosa Albizia •ulibrissin
Tree of heaven Ailanthis altissima
Privet Lonicera sinense
Amur honeysuckle Lonicera mackii
Wisteria Wisteria sinensis
Porcelain berry Am elopsis brevi edunculata
English i Hedera helix
Japanese or Wax-leaf ligustrum Ligustrum japonicum
Toe o f:Slope;
Southern red oak Quercus falcata
Yellow poplar Liriodendron tuli ifera
White oak Quercus alba
White ash Fraxnius americana
Sourwood Ox dendrum arboretum
Red maple Acer rubrum
Catalpa Catalpa s eciosa
Sweet um Li uidambar st raciflua
Table 3
Long Creek Vegetation
Canopy
Sycamore Platanus occidentalis
Beech Fa us randifolia
River birch Betula ni ra
Water oak Quercus hellos
Cottonwood Po ulus deltoides
Sweet um Liquidambar st raciflua
Black willow Salix ni ra
Box elder Acer ne undo
American elm Ulmus americana
Red.ma le Acer rubrum
Loblolly pine Pin us taeda
S,ubcanopy
Alder Alnus serrulata
Redbud Cercis canadensis
Red cedar Juniperus vir iniana
Winged elm Ulmus alata
Pawpaw Asimina triloba
Flood plain Shelf
Silk dogwood Corpus amomum
Silky willow Salix sericea
Alder Alnus serrulata
Spicebush Lindera benzoin
Toe of<Slope abovefloodplain
White oak Quercus alba
Sweet um Li uidambar st raciflua
Black walnut Ju lans ni ra
Yellow poplar Liriodendron tuli ifera
Shortleaf pine Pinus echinata
Mockernut hickory Ca rya tomentosa
Pignut hicko Ca rya labra
Red cedar Junl erus vir iniana
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Table 6
Freedom Park Potential Planting List
<.. ?13otanical'Name Common Name Size 'Slope Placement" Root Structure Exposure ;;Comments
belia grandiflora * Glossy Abelia 3-5' Mid/Top fibrous Sun/Part Shade Exotic; a number of cultivars available
esculus parviflora Bottlebrush Buckeye 8-12' Mid taproot Sun/Shade Native
ralia spinosa Devils Walking Stick 10-20' Mid colonial/fibrous Sun/Part Shade Native; thorny stems
ronia arbutifolia * Chokecherry 8-10' Toe/Mid fibrous Sun Native
simina triloba Pawpaw 15-20' Toe colonial/fibrous Part shade/Shade Native
Buddleia davidii Butterflybhsh 5-10' Mid fibrous Sun Exotic; a number of cultivars available
Callicarpa americana * American Beautyberry 6' Toe fibrous Sun Native
Calycanthus floridus * Sweet Shrub 8-10' Mid colonial/fibrous Part shade/Shade Native
Ceonothus americanus New Jersey Tea 3' Top fibrous Sun/Part Shade Native
Cephalanthus occidentalis * Button Bush 6-10' Toe fibrous Sun/Part Shade Native
Clethra alnifolia * Sweetpepper Bush 3-10' Toe/Mid/Top colonial/fibrous Sun Native; a number of cultivars available
Cornus amomum * Silky Dogwood 10' Toe/Mid colonial/fibrous Sun/Part Shade native
Cornus sericea * Red Twig Dogwood 6-8' Toe/Mid colonial/fibrous Sun Native ;a number of cultivars available
Cotoneaster divaricatus Spreading Cotoneaster 3-5' Top fibrous Sun Exotic; a number of cultivars available
Cytisus scoparius Scotch Broom 5' Mid/Top taproot/fibrous Sun Exotic
Diervilla sessilifolia Southern Bush-Honeysuckle 3-5' Top fibrous Sun/Part Shade Native
Fothergilla gardenii * Dwarf Fothergilla 3-5' Top fibrous Sun/Part Shade Native; a few cultivars available
Hydrangea arborescens * Smooth Hydrangea 3-5' Top fibrous Part shade/Shade Native
Hydrangea macroplylla Big-leaf Hydrangea 3-6 Mid/Top fibrous Part shade/Shade Exotic; a number of cultivars available
Hypericum frondosum 'Sunburst' * Sunburst St Johnswort 3' Top fibrous Sun/Part Shade Native
Hypericum 'Hidcote' St Johnswort 3' Top fibrous Part shade/Shade Exotic
Hypericum prolificum * Shrubby St Johnswort 5' Top fibrous Sun/Part Shade Native
Ilex glabra Inkberry Holly 3-6 Top fibrous Sun Native; a number of cultivars available
Ilex verticillata * Winterberry Holly 3-10' Toe/Mid fibrous Sun/Part Shade Native; a number of cultivars available
Illicium parviflorum Anise 6-10' Mid fibrous Sun/Shade
Itea virginica * Virginia Sweetspire 3-5' Toe/Mid/Top fibrous Sun/Part Shade Native; a few of cultivars available
Juniperus sp. Juniper Species 1-5' Toe/Mid/Top fibrous Sun Exotic; a number of cultivars available
Leucothoe axillaris Dog Hobble 3-5' To fibrous Part shade/Shade Native
Physocarpus opulifolius Ninebark 5-10' Toe/Mid fibrous Sun/Part Shade Native
Pseudocydonia sinensis Flowering Quince 5-10' Mid/Top taproot/fibrous Sun/Part Shade Exotic
Rhododendron sp. Rhododendron species 4-12' Toe/Mid/Top fibrous Part shade/Shade Native; many species available
Rhus sp. * Sumac species 5-12' Mid taproot Sun Native
Salix seresia Silky willow 10-20' Toe colonial/fibrous Sun/Part Shade Native
Sambucus canadensis * Elderberry 10' Toe colonial/fibrous Sun Native
Spiraea sp. Spirea species and cultivars 3-5' Mid/Top fibrous Sun/Part Shade Exotic; a number of cultivars available
Staphylea trifolia Bladdernut 6-10' Toe/Mid colonial/fibrous Part shade/Shade Native
Symphoricarpos orbiculatus * Coralberry 24 Toe/Mid/Top colonial/fibrous Sun/Shade Native
Vaccinium sp. * Blueberries species and cultivars 3-10' Mid/Top colonial/fibrous Sun Native; many species available
Viburnum sp. * Viburnum species 6-12' Toe/Mid colonial/fibrous Sun/Shade Native
anthorhiza simplicissima * Yellowroot 3' Toe/Mid/Top colonial/fibrous Part shade/Shade Native
Zenobia pulverulenta Dusty Zenobia 3-5' Top coloniallfibrous Sun/Part Shade Native
Note: Asterisked plants would be top choices subject to availability
Survey of Storm Water Outfalls
Little Sugar Creek at Freedom Park
A field inventory of storm water discharges into Little Sugar Creek (Creek) at Freedom Park was
completed on June 20, 2002. Locations are presented in Figure 6. Below is a comprehensive discussion
of each location, its type, and recommended actions. For each location, Alternative A presents the best
management practice (BMP) recommended to treat storm water under the conditions of an unlimited
budget and scope. The proposed action at this time, within the Scope of Work, budget, and Project Area
constraints, is presented in Alternative B. In those cases where Alternative A is considered feasible and is
the recommended action, Alternative B is not mentioned.
Typical renderings of example storm water BMPs applicable to Freedom Park are also included, courtesy
of the Center for Watershed Protection. The bioretention/rain garden rendering exhibits landscaping
features as well as storm water treatment. Both the dry or grassed swale and infiltration trench/gallery
renderings feature designs to encourage storm water infiltration.
1. A 7' x 5' concrete box culvert.
The culvert outlet is at Creek level. This inflow drains East Boulevard and an unknown area upslope.
The culvert was supplying some base flow seepage to the Creek on June 20, 2002, the day the survey
was performed. The drainage area and land-use for this inflow are unknown.
Alternative A: The size and location of this drain generate storm water treatment problematic and is
beyond the scope of the current stream restoration project. Storm water treatment would have to
begin well outside the Freedom Park boundaries to be effective. However, given the large storm
water volume contributed by this outlet, the greatest improvement in the Creeks water quality would
involve a water quality BMP retrofit of this inflow.
Alternative B: No action. This structure is not impacted by the proposed stream alignment or
construction activities.
2. An 18" diameter concrete culvert.
The culvert outlet daylights approximately 3 feet above Creek level and spills onto the concrete creek
lining before draining into the Creek. This culvert was dry on the day of the survey. The culvert
drains the tennis courts entrance road and parking lot on the east side of the Creek. The drainage area
for this culvert is 1.72 acres (1.21 acres impervious, 0.51 acres grass and shrub).
Alternative A: There is considerable potential to treat storm water runoff at this site by enlarging the
grassed swale on the north side of the tennis courts. Construction would involve daylighting the
storm drain upslope of the swale, and slightly enlarging and deepening the Swale. Overflow from the
swale would need to be stepped down to Creek level.
Alternative B: No action at this time. This structure is not impacted by the proposed stream
alignment or construction activities.
3. Turbid water entering the Creek along east bank from under concrete lining.
Alternative A: Check the Creek for sanitary sewer leak by notifying Mecklenburg County (County)
Department of Environmental Protection (DEP).
09177-017-018 B-1 October 2002
Little Sugar Creek at Freedom Park
Stream Restoration Plan
4. Flared 5' steel culvert entering at Creek level.
The culvert was dry on the survey day. The culvert drains a concrete lined Swale that runs from a
straightened stream channel behind private housing. This channel collects runoff from three road
crossings and the neighborhood on the west side of the park. The culvert also collects runoff from the
playing field area just south of the main drainage. The drainage area for this culvert is 53.53 acres
(46.70 acres single-family residential, 6.83 acres grassed playing field). It is unclear if this culvert
runs above or below the sanitary sewer crossing at this site.
Alternative A: There is considerable potential to treat storm water runoff at this site by removing the
concrete lining and constructing a larger grassed Swale along the current drainage course within the
park boundaries. Construction would involve removing the existing concrete lining, and enlarging
and deepening the swale. Overflow from the swale would need to be stepped down to Creek level.
Alternative B: The culvert outlet will be located on the inner berm area of a proposed stream
meander. Sheet flow will then be encouraged to infiltrate. It will be necessary to stabilize the stream
bank with hard substrate immediately adjacent to and below the outfall to prevent erosion. Removing
the concrete lining was not considered as part of this Alternative because its location is outside the
Project Area.
5. Channelized surface inflow has scoured 4' to 5' into the stream bank.
The channel was covered with kudzu and dry on the survey day. The channel becomes a rock-lined
3' x 1' channel upslope of the walking trail that parallels the east stream bank and collects some local
runoff. The channel drains a culvert running under a private garage and lot (1438 Sterling Avenue).
The origin of the drain is two road culverts on Sterling Avenue in front of this property. The total
drainage area for this inflow is 5.85 acres (5.66 acres single-family residential, 0.31 acres forested
local drainage associated with the lower channel).
Alternative A: Proposed channel restoration plans do not allow for a floodplain level infiltration
gallery at the outlet of this channel. There is an opportunity to create a significant rain garden
running from the break-in slope to the stream bank. Outflow from the rain garden would need to be
stepped down to stream level. A second possibility would be to create a lateral infiltration Swale with
an overflow outlet that could be stepped down to stream level. The swale would parallel the current
walking trail along the east stream bank.
Alternative B: This area will become part of a stream channel meander with appropriate action
occurring during construction.
6. A 2" diameter half-filled concrete culvert that drains extensive storm drain network underlying
parking lots and playing fields on west bank of the Creek.
The channel was dry on the survey day. The drainage area for this culvert is 19.51 acres (2.20 acres
single-family residential, 10.86 acres grassed playing field, 6.45 acres impervious road and parking
areas).
Alternative A: Given the proximity of the culvert outlet to the stream and the proposed alteration to
the Creek's current course, at this point there is the potential to construct an infiltration gallery within
the newly constructed floodplain of the restored channel. Construction would involve excavating the
current storm drain outlet and raising it to the level of the new floodplain. Water from the culvert
outlet would be allowed to infiltrate into a perforated pipe network underlying the floodplain.
09177-017-018 B-2 October 2002
Little Sugar Creek at Freedom Park
Stream Restoration Plan
tream
Alternative B: The culvert outlet will
infiltrate on thebnner berm andp geot t dsbench
meander. Sheet flow will then be encouraged to
area. It will be necessary to stabilize the stream bank with hard substrate immediately adjacent to and
below the outfall to prevent erosion.
7. Large excavated low bank area covered with ads a down obvious o acon cet apron channel on the easot bthe stream anks There
visible. There is a concrete/cobble ramp
is no obvious collection area upslope of this feature and it likely only contributes local drainage to the
Creek.
Alternative A: This area will become part of a stream channel meander with appropriate action
occurring during construction.
8. A 3' trapezoidal flume draining a small portion of the west bank parking area. surface The flume drains under a sidewalk, p b nkg Aagroximate containareaer,
acres (100 percent
over some riprap from the top of the PP
impervious roadway and parking surfaces).
eitherl tie this drain into alinteration to
Alternative A: Given the close proximity s the outlet
and the proposed the Creek's current course at this point, there i potential e infiltration
the
within
newly gallery proposed for inflow No. 6 or construct a ontruPon twould involvegahllery
routing of runoff from
constructed floodplain of the restored channel.
the top of the bank to the level of the new k floodplain. from the alternative cons derarion
to infiltrate into a perforated pipe network underlying
would involve the use of permeable pavement or curbing to allow infiltration of runoff from this
relatively small impervious area.
Alternative B: The culvert outlet will be located on the inner berm area of a proposed stream
bank intrate on the inner berm and vegetated bench
meander. Sheet flow will then be encouraged
d substrate immediately adja cent to and
area. It will be necessary to stabilize the stream
below the outfall to prevent erosion.
9. A 3' trapezoidal flume draining the southeast portion of the west bank parking area. top of the
This flume drains under a sidewalk and flows s (?OOepe?cent impervious rroadwaythand parking
bank. Approximate drainage area is 0.5 acres
surfaces).
estrational Given the would fall downstream of the
Alternative A: Unlike Inflows 6 and 8, this
proximity of this outlet to
proposed enhanced floodplain of the channel
the stream, there is little opportunity to construct an infiltration gallery at this point unless it is tied
into the infiltration gallery serving Inflows 6 and 8. An alternative runoff sides t ohis would invo small
use of permeable pavement or curbing to allow infiltration o
impervious area.
Alternative B: No action at this time. This structure is not impacted by the proposed stream
alignment or construction activities.
B-3
October 2002
09177-017-019
Little Sugar Creek at Freedom Park
Stream Restoration Plan
10. A 16" concrete culvert with welded steel grate.
This pipe appears decommissioned although there appeared to be some base flow seepage draining
from the pipe. The pipe outlet is approximately 2 feet above the creek base flow level.
Alternative A: Remove or seal off pipe during construction if decommission can be verified.
11. Inflow from dammed Dairy Branch tributary.
The right side of the dam, facing downstream, appears to allow surface flow over the dam. One storm
water drain from the west bank parking lot (approximately 1/4 acre, 100 percent impervious)
discharges into an impounded pool upstream of the dam. Some diffuse seepage through the riprap
below the dam was evident on the survey day.
Alternative A: Dam integrity should be determined on right side of channel, facing downstream.
The riprap apron below the dam appears stable and should be left as is during construction and
monitored after stream restoration.
12. Small top of bank surface inflow (likely a pedestrian trail) allows local inflow directly into the Creek.
Alternative A: Bank landscaping to discourage overbank drainage.
13. Approximately 20 linear feet of bank, 1' to 2' in height, is eroding as flow is directed towards the west
bank by a medial bar and bedrock dyke. There is a top of bank headcut where local surface flow
drains directly into the Creek from the top of the bank.
Alternative A: If improvement is necessary, this area will become part of a stream channel meander
with appropriate action taking place during construction.
14. A 20" concrete culvert entering stream at Creek level.
The pipe is halfway full of sediment. This culvert collects an extensive storm drain system under the
seating facing the stage on the pond island. The drainage wraps around the north end of the pond and
extends to the top of slope above the seating area. Some seepage was evident on the day of the
survey. The drainage area for this culvert is 9.77 acres (1.96 acres single-family residential, 7.81
acres grassed playing field). The culvert inlet is approximately 10' below ground level.
Alternative A: Given the proximity of the culvert outlet to the stream and the proposed alteration to
Little Sugar Creek's current course, at this point there is the potential to construct an infiltration
gallery within the newly constructed riparian bank of the restored channel. Construction would
involve excavating the current storm drain outlet and raising the outlet to the level of the new
floodplain. Water from the culvert outlet would be allowed to infiltrate into a perforated pipe
network underlying the riparian zone. It should be noted that this drain collects runoff from a large
grassed area with minimal impervious surface.
Alternative B: No action at this time. This structure is not impacted by the proposed stream
alignment or construction activities.
09177-017-018 B-4 October 2002
Little Sugar Creek at Freedom Park
Stream Restoration Plan
15. A 26" concrete culvert drains from the top of the bank over a concrete apron into stream.
The culvert runs from two street drains on Sterling Avenue, then under 1628 Sterling Avenue and
through a forested area. The culvert was dry on the day of the survey. The drainage area for this
culvert is 8.83 acres of single-family residential housing.
Alternative A: Proposed channel restoration plans do not allow for a floodplain level infiltration
gallery at the outlet of this channel. There is an opportunity to create a significant rain garden
running from the break in slope to the stream bank. Outflow from the rain garden would need to be
stepped down to stream level. A second possibility would be to create a lateral infiltration swale with
an overflow outlet that could be stepped down to stream level. The swale would parallel the current
walking trail along the east stream bank.
Alternative B: No action at this time. This structure is not impacted by the proposed stream
alignment or construction activities.
16. A 26" cemented steel culvert at top of bank.
This likely served as an outlet drain for the Freedom Park pond and is decommissioned. The culvert
was dry on the survey day.
Alternative A: Remove or seal off pipe during construction.
17. A 26" mid-bank concrete flume that drains mid bank into the Creek.
This culvert drains a storm grate located in the nature museum parking lot. Runoff occurs from the
parking lots and entrance road to the museum. The culvert was dry on the survey day. The drainage
area for this culvert is 1.16 acres, 0.96 acres of which is impervious asphalt. The remainder consists
of a pervious landscaped traffic island.
Alternative A: There is a scope for the construction of a small rain garden to treat the parking lot
runoff at this site. The existing culvert intake would need to be sealed and runoff routed into an
excavated area where a rain garden could be sited. Considerable room exists for such a structure as
two buildings have recently been demolished near the culvert intake.
Alternative B: Outfall improvement using hard substrate will be made during construction in an
effort to prevent erosion.
18. A 24" concrete culvert serving as a drainage outlet for the vertical riser in Royce Pond.
The surface area of the pond is approximately 6.12 acres, including a 0.68-acre island. Some seepage
was noted on the day of the survey.
Alternative A: Given the close proximity of this outlet to the stream and the proposed alteration to
the Creek's current course at this point, there is considerable potential to tie this drain into an
infiltration gallery within the newly constructed floodplain of the restored channel. Construction
would involve the routing of runoff from the outlet culvert to the level of the new floodplain. Water
from the culvert outlet would be allowed to infiltrate into a perforated pipe network underlying the
floodplain. Given the considerable waterfowl population that utilizes Royce Pond year round,
treatment of pond overflow would certainly enhance downstream water quality.
09177-017-018 B-5 October 2002
Little Sugar Creek at Freedom Park
Stream Restoration Plan
Alternative B:
19. A 6' concrete culvert entering the Creek from the east bank.
This serves as storm drain conveyance from Princeton Avenue. The culvert is slightly below Creek
level and it is not clear if seepage was occurring on the day of the survey.
Alternative A: The size and location of this drain generate storm water problematic and beyond the
scope of the current project. Storm water treatment would have to begin well outside the Freedom
Park boundaries to be effective. However, given the large storm water volume contributed by this
outlet the greatest improvement in the Creek's water quality would involve a water quality BMP
retrofit of this and site one inflows.
Alternative B: No action at this time. This structure is not impacted by the proposed stream
alignment or construction activities.
20. An 18" concrete culvert entering Creek from the west bank.
This culvert travels from a structure draining a 0.29-acre grassed depression near the south entrance
to Freedom Park. The culvert was dry on the day of the survey.
Alternative A: Seal storm drain. This storm drain seems like overkill. It drains a small, grassed
depression on the east side of the Princeton Avenue Freedom Park entrance. Water in this depression
should simply be allowed to infiltrate in place rather than be piped to the stream channel.
Alternative B: No action at this time. This structure is not impacted by the proposed stream
alignment or construction activities.
21. A 2' x 4' open channel that enters the Creek from the top of the east bank.
The channel drains 4.60 acres of a forested area downslope of the Nature Museum.
Alternative A: Runoff from this channel would likely have good water quality and a low delivery
rate to the Creek given the complete forest cover of the drainage area. Present stream restoration
plans call for a significant relocation of the channel through this site that may completely remove this
as a storm water input to the Creek. If the channel retains its present position, the recommendation is
to simply step this channel down to Creek level.
Alternative B: Meander construction will address the location of this channel. Channel drainage
into the Creek will be protected with a hardened substrate to prevent erosion.
09177-017-018 B-6 October 2002
Little Sugar Creek at Freedom Park
Stream Restoration Plan
A 8 C D E F G H
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Freedom Park - Little Sugar Creek
HDR Engineering, Inc. Locations
Channel Restoration
®M asx d wool aw PnM 14 uMq xa ?
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y y * m y y v ?
y 41 b u .b y ?-yy w
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PLAN ---DER"
Bioretention areas
are landscaping
features adapted to
treat on-site
stormwater runoff.
PO?/O/NG
;1111 _llllll=? MULCH
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-= III
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Dry or Grassed Swale
CULVERT
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Dry swales are similar in design
to hioretention areas. These
designs incorporate a fabricated
soil bed into their design.
50,% SANG/SO °o LOAM
PROF/-E
Infiltration Trench/Gallery
PARKING LOT
BYPASS
(TO DETENTION FACILITY)
An infiltration trench is a rock-filled
trench with no outlet that receives
stormwater runoff. Stormwater runoff
passes through some combination of
pretreatment measures, such as a swale
and detention basin, and into the trench.
CONCRETE
LEVEL
SPREADER
PLUNGE VVVVVVVVAP
POOL
7AP VV?VV
V AP AP
?Ak AP AP Ak 41
VVVVVV
11frI " V Ak AP V V Ak
INFILTRATION
TRENCH
WITH PEA GRAVEL
FILTER LAYER
OVER WASHED
BANK RUN GRAVEL
AGGREGATE
GRASS
CHANNEL
(LESS THAN 1 %
SLOPE)
t

t

OVERFLOW
PLAN VIEW