20071921 Ver 1_More Info Received_20071218

WITHERS ~~~ RAYEN EL
ENGINEERS I PLANNERS
December 17, 2007
NC-Division of Water Quality
Attn: Ms. Lia Myott
2321 Crabtree Blvd.
Raleigh, North Carolina 27604
Re: Request forAdditionalinformation - BSP Atlantic
W&R Project #:205518
DWQ Project #: 07-1921
Dear Ms. Myott,
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We received your request for additional information on November 29`h, regarding the
proposed impacts associated with the BSP Atlantic Project. I have included a brief
response to each of your requests below.
Your letter asks for the following information:
1) Discharge from BMP #1
a) Please extend the outlet pipe all the way to the stream at an angle that will not
cause erosion to the streambank and provide sufficient rip-rap at the discharge
point such that the streambed and banks shall be stable
As designed, we do not believe that the outlet pipe needs to modified in order to
protect the streambank. Specifically, due to the high tail water at the io year
storm, it appears that the outlet velocity at the pad will be non-erosive (: e. it will
be underwater). In theory, there maybe very little flow exiting the pipe, because it
is underwater. We have provided the sizing calculations for the rip-rap pad and
the FEMA flood profile documenting the tailwater elevation during the io year
event.
b) Please provide outlet calculations for BMP #1.
Outlet calculations forBMP's i and 2 are included with the attachments.
2) Discharge form BMP #2
a) Please extend the outlet pipe all the way to the stream at an angle that will not
cause erosion to the streambank and provide sufficient rip-rap at the discharge
point such that the streambed and banks shall be stable.

• Page 2
December 17, 2007
Rather than extend the existing pipe, the applicant proposes to construct a
bypass Swale from the outlet pipe to the stream channel The Swale has been
angled such that, when it turns into the stream, the flow will not de-stabilize the
opposite banks. The revised maps and calculations are included with the
attachments.
3) PCN -Please ensure that any changes in stream or riparian buffer impacts due to
BMP modifications are enumerated in a new version of the PCN form.
See attached.
Please feel free to call if you have questions or require additional information.
Sincerely,
WITHERS & RAVENEL, INC.
-T~
Todd Preuninger
Director of Wetlands and Biological Sciences
Attachments:
i) Revised PCN
z) Calculations for BMP a and 2
3) FEMA Flood elevations

Office Use Only: Form Version March OS
USACE Action ID No. DWQ No. G ~ O''1 ~ 192. I
(If any particular item is not applicable to this project, please enter "Not Applicable" or "N/A".)
I. Processing
Check all of the approval(s) requested for this project:
^ Section 404 Permit ® Riparian or Watershed Buffer Rules
^ Section 10 Permit ^ Isolated Wetland Permit from DWQ
^ 401 Water Quality Certification ^ Express 401 Water Quality Certification
2. Nationwide, Regional or General Permit Number(s) Requested: NA
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 Ecosystem Enhancement Program (NCEEP) is proposed
for mitigation of impacts, attach the acceptance letter from NCEEP, complete section VIII,
and check here:
5. If your project is located in any of North Carolina's twenty coastal counties (listed on page
4), and the project is within a North Carolina Division of Coastal Management Area of
Environmental Concern (see the top of page 2 for further details), check here: ^
II. Applicant Information
1. Owner/Applicant Information
Name: BSP Atlantic LLC -Attn: Ed Hal
Mailing Address: 5400 Trinity Road, Suite 307
Raleigh, North Carolina 27607
Telephone Number: 919-854-5551 Fax Number: 919-854-7913
E-mail Address: ehallberg~a,broadstreetpartners.com
2. Agent/Consultant Information (A signed and dated copy of the Agent Authorization letter
must be attached if the Agent has signatory authority for the owner/applicant.)
Name: Todd Preuninaer
Company Affiliation: Withers and Ravenel
Mailing Address: 111 MacKenan Drive
Cary, North Carolina 27511
Telephone Number: 469-3340 Fax Number: 238-2099
E-mail Address: tpreuninger(a,withersravenel.com
Page 1 of 9

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: BSP Atlantic
2. T.LP. Project Number or State Project Number (NCDOT Only): NA
3. Property Identification Number (Tax PIN): 1715525453
4. Location
County: Wake Nearest Town: Raleigh
Subdivision name (include phase/lot number): BSP Atlantic
Directions to site (include road numbers/names, landmarks, etc.): The subject property is
approximately 47 acres in size and is located and is located due west of the intersection of
Interstate 440 and Capital Blvd (US 401) (Latitude:35.8165008 °N
Lon~itude:78.6100024°W in Raleigh, Wake County, North Carolina.
5. Site coordinates (For linear projects, such as a road or utility line, attach a sheet that
separately lists the coordinates for each crossing of a distinct waterbody.)
Decimal Degrees (6 digits minimum)::35.8165008 °N 78.6100024° °W
6. Property size (acres): 47
7. Name of nearest receiving body of water: Crabtree Creek
8. River Basin: Neuse
(Note -this must be one of North Carolina's seventeen designated major river basins. The
River Basin map is available at http://h2o.enr.state.nc.us/admin/maps/.)
9. Describe the existing conditions on the site and general land use in the vicinity of the project
at the time of this application: The site is currently wooded and is surrounded by
residential housing as well as commercial ventures.
Page 2 of 9

10. Describe the overall project in detail, including the type of equipment to be used: The
proposed project consists of the construction of residential housing (i.e. apartments). Typical
earth moving equipment (such as excavators) will be used to install the infrastructure.
11. Explain the purpose of the proposed work: The proposed project is intended to meet the
rg owing demand for housing in this area.
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 Wetlands were delineated by Withers & Ravenel during April, 2006. A
site meeting was conducted with the NC-DWQ on February 15, 2007 (DWQ EXP# 07-0566) to
verify stream origin points A copy of the NC-DWQ letter is attached. In addition pre -
application meetings were held with DWQ on 1/29/07 and 2/15/07 to discuss avoidance and
minimization issues (see below~_
V. Future Project Plans
Are any future permit requests anticipated for this project? If so, describe the anticipated work,
and provide justification for the exclusion of this work from the current application.
No additional impacts will be needed to complete this project.
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. Each impact must be
listed separately in the tables below (e.g., culvert installation should be listed separately from
riprap dissipater pads). Be sure to indicate if an impact is temporary. All proposed impacts,
permanent and temporary, must be listed, and must be labeled and clearly identifiable on an
accompanying site plan. All wetlands and waters, and all streams (intermittent and perennial)
should 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. Provide a written description of the proposed impacts: The proposed permanent impacts
consist of 8 562 SF (Zl: 3 711 and Z2: 4 851) of riparian buffer for the construction of a
bride. In addition 5 349 SF (Z1: 2 544 SF Z2: 2,805 SF~permanent riparian buffer is
Page 3 of 9

proposed for the installation of a b~-pass Swale for constructed wetland #2. No wetlands or
streams will be impacted by the as a result of this project.
2. Individually list wetland impacts. Types of 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.
Wetland Impact Type of Wetland Located within Distance to Area of
Site Number Type of Impact (e.g., forested, marsh, 100-year Nearest Impact
(indicate on map) herbaceous, bog, etc.) Floodplain Stream (acres)
(yes/no) (linear feet)
NA NA NA NA NA NA
Total Wetland Impact (acres) NA
3. List the total acreage (estimated) of all existing wetlands on the property:
4. Individually list all intermittent and perennial stream impacts. Be sure to identify temporary
impacts. Stream impacts include, but are not limited to placement of fill or culverts, dam
construction, flooding, relocation, stabilization activities (e.g., cement walls, rip-rap, crib
walls, 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. To calculate acreage. multiply length X width. then divide by 43.560.
Stream Impact
Perennial o Average Impact Area of
Number Stream Name Type of Impact ~
Intermittent Stream Width Length Impact

(indicate on map) .
Before Impact
(linear feet)
(acres)
NA NA NA NA NA NA NA
Total Stream Impact (by length and acreage) NA
5. Individually list all open water impacts (including lakes, ponds, estuaries, sounds, Atlantic
Ocean and any other water of the U.S.). Open water impacts include, but are not limited to
fill, excavation, dred~in~, flooding. drainage, bulkheads. etc.
Open Water Impact
Name of Waterbody Type of Waterbody Area of
Site Number
~
(if applicable) Type of Impact (lake, pond, estuary, sound, bay, Impact
indicate on ma
(
p) ocean etc.
)
(acres)
NA NA NA NA NA
Total Open Water Impact (acres) NA
6. List the cumulative impact to all Waters of the U.S. resulting from the proiect:
Stream Impact (acres): 0
Wetland Impact (acres): 0
Open Water Impact (acres): 0
Total Impact to Waters of the U.S. (acres) 0
Total Stream Impact (linear feet): 0
7. Isolated Waters
Do any isolated waters exist on the property? ^ Yes ®No
Page 4 of 9

Describe all impacts to isolated waters, and include the type of water (wetland or stream) and
the size of the proposed impact (acres or linear feet). Please note that this section only
applies to waters that have specifically been determined to be isolated by the USACE.
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.): NA
Proposed use or purpose of pond (e.g., livestock watering, irrigation, aesthetic, trout pond,
local stormwater requirement, etc.): NA
Current land use in the vicinity of the pond: NA
Size of watershed draining to pond: NA Expected pond surface area: NA
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. Prior to site plan development,
the applicant requested that a detailed wetland delineation be conducted so that impacts to
wetlands and `waters' could be minimized. The City of Ralei hg is requiring a collector street
connection between Meadow Wood Boulevard and Ratchford Drive. The original site plans
called for two creek crossings at the confluence of Crabtree Creek and an un-named tributary.
We examined crossing further to the east to minimize impacts, however, horizontal and vertical
designn standards limited the crossing location to the existing stub road and right-of--way. We
also looked at crossing further to the west but this alignment would impact existing buildings,
not owned b t~pplicant As a compromise and in order to minimize impacts the applicant
proposes to shift approximately 400 feet of the existing right-of--way to the west, and will span
the entire creek crossing using a bride avoiding impacts to stream channels altogether.
Although there are parallel impacts to the riparian buffer as stated above these impacts could
not be avoided due to the fact that there is an existing building_just west of the alignment.
Although two other points of ingress and egress are located in the northern portion of the
property via Meadwood Boulevard and Mellowfield Drive at build-out the proposed
development will consist of 1 200 residential condominium/townhome units. Based on the
traffic study conducted b~Rame~Kemp if the connection at the southern end of the property is
not constructed it will lead to operational concerns at some intersections, as well as cause
significant increases in delays and queues at the intersection of Atlantic Avenue and Meadowood
Boulevard. These delays could also affect the emergency response time if an accident were to
Page 5 of 9

occur within or adjacent to the proposed development. A copy of the Traffic analysis is included
with the attachments, for your review.
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 January 15, 2002, mitigation will be required when
necessary to ensure that adverse effects to the aquatic environment are minimal. Factors
including size and type of proposed impact and function and relative value of the impacted
aquatic resource will be considered in determining acceptability of appropriate and practicable
mitigation as proposed. Examples of mitigation that may be appropriate and practicable include,
but are not limited to: reducing the size of the project; establishing and maintaining wetland
and/or upland vegetated buffers to protect open waters such as streams; and replacing losses of
aquatic resource functions and values by creating, restoring, enhancing, or preserving similar
functions and values, preferable in the same watershed.
If mitigation is required for this project, a copy of the mitigation plan must be attached in order
for USACE or DWQ to consider the application complete for processing. Any application
lacking a required mitigation plan or NCEEP 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/newetlands/strmgide.html.
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.
The applicant proposes payment to the NC-EEP to satisfy mitigation requirements.
2. Mitigation may also be made by payment into the North Carolina Ecosystem Enhancement
Program (NCEEP). Please note it is the applicant's responsibility to contact the NCEEP at
[phone] to determine availability, and written approval from the NCEEP indicating
that they are will to accept payment for the mitigation must be attached to this form. For
additional information regarding the application process for the NCEEP, check the NCEEP
website at http://h2o.enr.state.nc.us/wrp/index.htm. If use of the NCEEP is proposed, please
check the appropriate box on page five and provide the following information:
Page 6 of 9

Amount of stream mitigation requested (linear feet): NA
Amount of buffer mitigation requested (square feet): 9,350
Amount of Riparian wetland mitigation requested (acres): NA
Amount ofNon-riparian wetland mitigation requested (acres): NA
Amount of Coastal wetland mitigation requested (acres): NA
IX. Environmental Documentation (required by DWQ)
1. Does the project involve an expenditure of public (federal/state/local) funds or the use of
public (federal/state) land? Yes ^ No
2. 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 aNEPA/SEPA document is required, call the SEPA
coordinator at [phone] to review current thresholds for environmental documentation.
Yes ^ No ^
3. If yes, has the document review been finalized by the State Clearinghouse? If so, please
attach a copy of the NEPA or SEPA final approval letter. Yes ^ No ^
X. Proposed Impacts on Riparian and Watershed Buffers (required by DWQ)
It is the applicant's (or agent's) responsibility to determine, delineate and map all impacts to
required state and local buffers associated with the project. The applicant must also provide
justification for these impacts in Section VII above. All proposed impacts must be listed herein,
and must be clearly identifiable on the accompanying site plan. All buffers must be shown on a
map, whether or not impacts are proposed to the buffers. Correspondence from the DWQ
Regional Office may be included as appropriate. Photographs may also be included at the
applicant's discretion.
1. Will the project impact protected riparian buffers identified within 15A NCAC 2B .0233
(Neuse), 15A NCAC 2B .0259 (Tar-Pamlico), 15A NCAC 02B .0243 (Catawba) 15A NCAC
2B .0250 (Randleman Rules and Water Supply Buffer Requirements), or other (please
identify )? Yes ® No ^
2. If "yes", 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.
Page 7 of 9

Zone* Impact
(square feet) Multiplier Required
Mitigation
1 11,604 3 (2 for Catawba) See below
2 7,656 1.5
Total 19,260 See below
* Zone 1 extends out 30 feet perpendicular from the top of the near bank of channel; Zone 2 extends an
additional 20 feet from the edge of Zone 1.
Mitigation will be required for the parallel buffer impacts in the amount of:
Z1: 2,021x3 = 6,063SF and Z2 2,191 X1.5 = 3,287
3. If buffer mitigation is required, please discuss what type of mitigation is proposed (i.e.,
Donation of Property, Riparian Buffer Restoration /Enhancement, or Payment into the
Riparian Buffer Restoration Fund). Please attach all appropriate information as identified
within 15A NCAC 2B .0242 or .0244, or .0260. The applicant proposes payment to EEP to
satisf~~ation requirements.
XI. Stormwater (required by DWQ)
Describe impervious acreage (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. If percent impervious surface exceeds 20%, please provide calculations
demonstrating total proposed impervious level. The proposed impervious for this project is
expected to be greater than 24%, therefore, constructed wetlands will be utilized to treat
Stormwater before it exits the site. The Stormwater mana eg ment plans have been submitted to
the City of Raleigh for preliminary approval We will forward the approval letter alon wg ith a
set of the construction drawings and calculations, when we receive it. During construction the
applicant will utilize sediment basins to prevent sediment from enteringjurisdictional stream
channels or wetlands.
XII. Sewage Disposal (required by DWQ)
Clearly detail the ultimate treatment methods and disposition (non-discharge or discharge) of
wastewater generated from the proposed project, or available capacity of the subject facility.
Sanitary Sewer
XIII. Violations (required by DWQ)
Is this site in violation of DWQ Wetland Rules (15A NCAC 2H .0500) or any Buffer Rules?
Yes ^ No
Is this an after-the-fact permit application? Yes ^ No
XIV. Cumulative Impacts (required by DWQ)
Page 8 of 9

Will this project (based on past and reasonably anticipated future impacts) result in additional
development, which could impact nearby downstream water quality? Yes ^ No
If yes, please submit a qualitative or quantitative cumulative impact analysis in accordance with
the most recent North Carolina Division of Water Quality policy posted on our website at
http://h2o.enr.state.nc.us/ncwetlands. If no, please provide a short narrative description: A
majority of the adjacent~arcels have alreadybeen developed. If any additional development
occurs on the a~acent parcels the owners will be required to comply with the NPDES Phase II
rules the Neuse Riparian Buffer Rules therefore we do not believe that this project will have a
negative impact on downstream water quality
XV. 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).
~. i~/~~-
Applicant/Agent's Signature Date ~
(Agent's signature is valid only if an authorization letter from the applicant is provided.)
Page 9 of 9

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1. N: 171552553 47.01 AC
2. D DETERMINED BY WITHERS AND RAVANEL, INC APRIL 20
3. DING TO F.E.MA PANEL 3720171500) AND
TED MAY 2, 2D06 PORBON OF THE SUBJECT PROPERTIES
E WRHIN A DESIGNATED FLOOD HAZARD ZONE
4. NOARY AND TOPOGRAPHY LOCATION PROVIDED
M RILEY SURVEYING, PA DATED MARCH 13, 2007
BSP ATLANTIC
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TOTAL DEVELOPMENT IMPACTS SUMMARY
SEE SHEETS I-4 DETAILED IMPACTS
ZONE 11MPACT AREA = 2,544SF
ZONE 2 IMPACT AREA = 2,605SF
TOTAL IMPACTS
NOTES:
1. PIN: 1715525453 47.01 AC
2. WETLAND DETERMINED BY WffHERS AND RAVANEL, INC APRIL 2006
3. ACCORDING TO F.E.MA PANEL 3720171500) AND
DATED MAY 2, 2006 PORTION OF THE SUBJECT PROPERTIES
LIE WITHIN A DESIGNATED FLOOD HAZARD ZONE.
4. BOUNDARY AND TOPOGRAPHY LOCATION PROVIDED
FROM RILEY SURVEYING, PA DATED MARCH 13, 2007
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NRCD Land Quality Section
NYDOT Dissipator Design Results
Pipe diameter (ft) 2.50
Outlet velocity (fps) 15.64
Apron length (ft) 20.00
AVG DIAM STONE THICKNESS
(inches) CLASS (inches)
3 A 9
6 B 22
> 13 B or 1 22 <
23 2 27

Type.... Master Network Summary Page 2.01
Name.... Watershed
File.... K:\OS\05-510\05518.00 Atlantic Broad Street\H-H\PondPack\BSP~Atlantic_BMPl.ppw
MASTER DESIGN STORM SUMMARY
Network Storm Collection: RDU NOAA 19 Desi
Total
Depth Rainfall
Return Event
---------- in Type RNF ID
--
2 ------
3.9900 ----------------
Time-Depth Curve ----------------
RDU NOAA 2yr
10 4.9800 Time-Depth Curve RDU NOAA l0yr
100 7.3700 Time-Depth Curve RDU NOAA 100yr
MASTER NETWORK SUMMARY
SCS Unit Hydragraph Method
(*Node=outfall; +Node=Diversion;)
(T run= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt)
Return HYG Vol Qpeak
Node ID
-----------
------ Type
---- Event
--
--- cu.ft Trun hrs

BMP
1
IN
POND -
2 ---------- --
128408 ----------
12.2000
BMP 1 IN POND 10 209319 12.2000
BMP 1 IN POND 100 338463 12.2000
MP 1 OUT POND 2 12,030 ~? '000
MP I OUT POND 10 208941 12.3000
Max
Qpeak Max WSEL Pond Storage
cfs ft cu.ft
-------- -------- ------------
96.09
65.09
85.43
49.49 203.67
64646 ~~-Y~
82697 ~~
*BMP 1 OUT JCT 2 157200 12.3000 35.41
*BMP 1 OUT JCT 10 268691 12.2000 69.10
*BMP 1 OUT JCT 100 952838 12.2000 83.19
LOT 1 - UNTREATE AREA 2 29172 12.2000 10.72
LOT 1 - UNTREATE AREA 10 59750 12.2000 19.92
LOT 1 - UNTREATE AREA 100 114753 12.2000 31.58
PRE - LOT 1 AREA 2 78459 12.2000 24.22
PRE - LOT 1 AREA 10 163290 12.2000 48.75
PRE - LOT 1 AREA 100 317305 12.2000 90.47
S/N: DOYXYWH3NLBE Withers & Ravenel
PondPack (10.00.015.00) 12:21 PM 12/16/2007

Project Name: BSP Atlantic
City/State: Raleigh, NC
Project #: 2050518
Date: 16-Dec-07
STORMWATER BMP #1 -CONSTRUCTED WETLAND (85% TSS Removal 8 40% TN Removal)
Orifice Calculator

Variables Constants
WQ Volume: 0.812534 Acre-ft 35394 cf g = 32.2 ft/s2
Head: 1.60 ft 0.8 ft Cd = 0.6
Draw down time: 48 hrs 172800 s
Orifice Area = 0.047561 sq. ft 6.848717 sq. in
Orifice Diameter= 3 in
Q = 0.289668 cfs ~~ ~ ~~ ^ ~~ ~

Type.... Master Network Summary Page 2.01
Name.... Watershed
File.... K:\OS\OS-510\05518.00 Atlantic Broad Street\H-H\PondPack\BSP Atlantic BMP2.ppw
MASTER DESIGN STORM SUMMARY
Network Storm Collection: RDU NOAA 14 Desi
Total
Depth Rainfall
Return Event in Type RNF ID
2 3.9900 Time-Depth Curve RDU NOAA 2yr
10 9.9800 Time-Depth Curve RDU NOAA l0yr
100 7.3700 Time-Depth Curve RDU NOAA 100yr
MASTER NETWORK SUMMARY
SCS Unit Hydrograph Method
(*Node=Outfall; +Node=Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=At: LR=Left6Rt)
Max
Return HYG Vol Qpeak Qpeak Max WSEL Pond Storage
Node
----- ID
------
------ Type
---- Event
------ cu.ft Trun
---------- -- hrs
--------- cfs
-------- ft
-------- cu.ft
------------
BMP 2 IN POND 2 193663 12.2000 51.13
BMP 2 IN POND 10 231660 12.2000 71.39
BMP 2 IN POND 100 371963 12.2000 92.97
BMP
Y 2
~ OUT POND 2 _ 143282
~ 12.6000 _ __ _5.89 _ 227.22 86702
1 BMP 2- OUT POND 10 231259 12.3000 90.92 227.87 106806
*POST-ROADWAY PH1 JCT 2 154696 12.6000 6.50
*POST-ROADWAY PH1 JCT 10 250417 12.3000 99.25
*POST-ROADWAY PH1 JCT 100 402896 12.2000 63.60
PRE-ROADWAY PH1 AREA 2 13109 12.3000 3.60
PRE-ROADWAY PH1 AREA 10 27289 12.3000 7.27
PRE-ROADWAY PHZ AREA 100 53032 12.3000 11.93
*PRE-RW PH1 OUT JCT 2 13109 12.3000 3.60
*PRE-RW PH1 OUT JCT 10 27289 12.3000 7.17
*PRE-RW PH1 OUT JCT 100 53032 12.3000 11.93
5/N. DOYXYWH3NLBE
PondPack (10.00.015.00}
11:59 AM
Withers ~ Ravenel
12/16!2007
(D-~(,Z.
~Q ~

Project Name: BSP Atlantic
CitX/State: Raleigh, NC
Project #: 2050518
Date: 16-Dec-07
STORMWATER BMP #2 -CONSTRUCTED WETLAND (85% TSS Removal 8 40% TN Removal)
Orifice Calculator
Q =Cd*A*(2gh)"(112)
Variables Constants
WQ Volume: 1.835698 Acre-ft 79963 cf g = 32.2 ft/s2
Head: 3.00 ft 1.5 ft Cd = 0~6
Draw down time: 48 hrs 172800 s
Orifice Area = 0.07847 sq. ft 11.29973 sq. in
Orifice Diameter = 4 in
,~
Q= 0.654426 cfs ~ ~~ (~~~~~

BMP2 Outlet Ditch
Project Description
Friction Method Manning Formula
Solve For Normal Depth
Input Data
Roughness Coefficient 0.078
Channet Slope 0.09800 ft/ft
Left Side Slope 3.00 ft!ft (H:V)
Right Side Slope 3.00 ft/ft (H:V)
Bottom Width 10.00 ft
Discharge 42.00 fl /s
Results
Normal Depth 0.77 ft
Flow Area 9.50 ft2
Wetted Perimeter 14.88 ft
Top Width 14.63 ft
Critical Depth 0.76 ft
Critical Slope 0.10531 Wft
Velocity 4.42 ft!s
Velocity Head 0.30 ft
Speufic Energy 1.08 ft
Froude Number 0.97
Flow Type Subcritical
GVF Input Data
Downstream Depth 0.00 ft
Length 0.00 ft
Number Of Steps 0
GVF Output Data
Upstream Depth 0.00 ft
Profile Description
Profile Headloss 0.00 ft
Downstream Velocity Infinity fUs
Upstream Velocity Infinity ft/s
Normal Depth 0.77 ft
Critical Depth 0.76 ft
Channel Slope 0.09800 fl/ft
Critical Slope 0.10531 fl!ft
Bentley Systems, Ine. Haestad Methods Setutlen Center FlowMaster [08.D1.OSB.OD]
12/16/2007 12:15:32 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-2D3-755-1666 Page 1 of 1

0
2~ --r
Table 8.05f Manhing's Roughness Coefficient

Lining Category

Llning Type

0-0.5 ft
(0-15 cm n -value
nvafue for Depth Ranges
0.5-2.0 ft
15-60 cm)

2.0 ft
> 60 cm)
Rigid Concrete 0.015 0.013 0.013
Grouted Riprap 0.040 0.030 0.028
Stone Masonry 0.042 0.032 0,030
Soil Cement 0.025 0.022 0.020
Asphalt 0.018 0.016 0.016
Unlined Bare Soil 0.023 0.020 0.020
Rock Cut 0.045 0.035 0.025
Gravel Riprap 1-inch (2.5-cm} Dso 0.044 0.033 0.030
2-inch (5~m) Dso 0.066 0.041 0.034
Rock Riprap 6-inch (15-cm) Dso 0.104 0.069 0.035
12-inch (30-cm) Dso -- 0.078 0.040
Note: Yalues listed are representative values For the respective depth ranges. Manning's roughness coefficients, n, vary with theflow depth.
DETERMINING SHEAR STRESS
Shear stress, T, at normal depth is computed for the lining by the following
equation:
T=yds
Td =Permissible shear stress
where:
T shear stress in Ib/ft2
`-(~-(-,~~{' ~ ~If-~ y = unit weight of water, 62.41b/ft3
d - flow depth in f[
~= ~~~ ~~ s = channel gradient in ft/ft.
s- ~ .~3F.-f ~;
If the permissible shear stress, Td, given in Table 8.OSg is greater than the
'"~ ~~~ j 1 ~~h~ ~ computed shear stress, the rprap or temporary lining is considered acceptable.
If a lining is unacceptable, select a lining with a higher permissible shear stress
and repeat the calculations for normal depth and shear stress. In some cases i[
may be necessary to alter channel dimensions [o reduce the shear stress.
Computing tractive force around a channel bend requires special considerations
because the change in flow direction imposes higher shear stress on the channel
bottom and banks. The maximum shear stress in a bend, Tb, is given by the
following equation:
Tb = KbT
where:
Tb = bend shear stress in tb/ft2
Kb = bend factor
T = computed stress for straight channel in Ib/ft2
The value of Kb is related to the radius of curvature of the channel at its center
line, R~, and the bottom width of the channel, B, Figure 8.OSe. The length of
channel requiring protection downstream from a bend, Lp, is a function of the
roughness of [he lining material and the hydraulic radius as shown in Figure
8.05f.
8.65.12
Rev 11!93

Appendices
Table 8.05g
Permissible Shear Stresses
for Riprap and Temporary
Liners
Permissible Unlt Shear Stress, T~
Lining Category Lining Type (Ib/ft )
Temporary Woven Paper Net 0.15
Juie Net 0.45
Fiberglass Roving:
Single 0.60
Double 0.85
Straw with Net i.45
Curled Wood mat 1.55
Synthetic Mat 2.00
dso Stone Size (inches)
Gravel Riprap 1 0.33
2 0.67
Rock Riprap 6 2.00
9 3.00
12 4.00
~,~ l
1 15 5.00
18 6.00
21 7.80
24 8.00
Adapted From: FHWA, FI)rC-15, April 1983, pgs. 17 & 37.
~eSlgn PrOCedUre- The following is a step-by-step procedure for designing a temporary liner for a
Temporary Liners channel. Because temporary liners have a short period of service, the design D
may be reduced. For liners that are needed For six months or [ess, the 2-yr
frequency storm is recommended.
Step 1. Select a liner material suitable for site conditions and application.
Determine roughness coefficient from manufacturer's specifications or Table
S.OSe, pg. 8.05.10.
Step 2. Calculate the normal flow depth using Manning's equation (Figure
8.OSd). Check to see that depth is consistent with that assumed for selection of
Manning's n in Figure 8.OSd, pg. 8.05.11. For smaller runoffs Figure S.OSd is
not as clearly defined. Recommended solutions can be determined by using the
Manning equation.
Step 3. Calculate shear stress at normal depth.
Step 4. Compare computed shear stress with the permissible shear stress for
the liner.
Step 5. If computed shear is greater than permissible shear, adjust channel
dimensions to reduce shear or select a more resistant lining and repeat steps 1
through 4.
Design of a channel with temporary lining is illustrated in Sample Problem
8.OSb, pg. 8.05.14.
Rev t?/93 8.05.13

240 , 240

230
220
210
0
z 200
~-
w
w
LL
Z
z
190
Q
w
J
W
180
43a
170
272
333
160
150
LEGEND

0.2% ANNUAL CHANCE ROOD
- - 1% ANNUAL CHANCE ROOD
- Z%ANNUALCHANCEFEOOD'
- 10% ANNUAL CHANCE FLOOD
%~~tiG~~~~~ STREAM BED
123 CROSS SECTION LOCATION
' DATANOT AVAILABLE
22000 24000 26000 28000 30000 32000 34000 36000 38000 40000 42000 44000
STREAM DISTANCE IN FEET ABOVE MOUTH
230 Q

W
EL'

220 ~ ~

~ Z
~
Q
a m
210 0 w
0

~ W
~

W

200 ~
190
aI
U
180
}
U
Z
W
(~
a U ~
z Z ~
w Q
170 w ~ D

~ ~
~
z U ~
W
Y z

W
J ~ 0
s Z
W Q
4
W
W

120P