20100251 Ver 1_Stormwater Info_20100709

WITHERS !!?a RAVENEL
ENGINEERS I PLANNERS I SURVEYORS
1410 COMMONWEALTH DRIVE, SUITE 1o1
WILMINGTON, NORTH CAROLINA, 28403
[phone]
FAX [phone]
TO: NC Divison of Water Quality - 401 Wetlands Unit
2-421 Crabtree Blvd
Raleigh, NC 27604
WE ARE SENDING YOU
? Shop Drawings
? Copy of Letter
E Attached
? Prints
? Change order
the following items:
? Specifications
COPIES DATE NO. DESCRIPTION
719110 Response to Request for More Information Letter (/ /1o)
719110 24x36 construction drawings
719110 Stormwater Management Report
719110 0&M Manuals (to be signed upon approval)

THESE ARE TRANSMITTED as checked below:
® For approval ? Approved as submitted ? Resubmit copies for approval
? For your use ? Approved as noted ? Submit copies for distribution
? As requested ? Returned for corrections ? Return corrected prints
? For review and comment ?
? FOR BIDS DUE 20 ? PRINTS RETURNED AFTER LOAN TO US
REMARKS:
Signature: W LUJ
Date: JUL 3 ZO10
DEW • N ER OJAUTY
MUMIXAMUMMORMWO
COPY TO: File SIGNED: Troy Beasley
if enclosures are not as noted, kindly notify us at once.
LETTER OF TRANS MAL
DATE 719110 JOB No. 020 00 0.10
ATTENTION Mr. Ian McMillan
PHONE # [phone]
RE. Bri htwater Medical Complex
Request for More Information Response
Stormwater design

o - 1oa.51

? Under separate cover via _
? Plans ? Samples
? Diskette ?
WITHERS RAVENEL
ENGINEERS I PLANNERS I SURVEYORS
July 9, 2010
Mr. Ian McMillan
NC Division of Water Quality
401 Oversight/Express Review Permitting Unit
2321 Crabtree Blvd
Suite 250
Raleigh, NC 27604
Re: Brightwater Medical Complex
DWQ Project # 10-0251
Mr. McMillan:
JUL
9 1 UlJ
NMA
???
1R
This letter is in response to your Request For More Information Letter,
dated May 3, 2010 for the Brightwater Medical Complex project.
The responses to the items listed in your letter are provided below:
1. Please clarify which parts of the proposed development are Phase I and Phase II on a
full-sized plan sheet that shows surface waters, topographic lines and all anticipated
impervious surfaces.
The information has been added to the plan sheets.
2. You must provide the Required items Checklist associated with each of the Wet
Detention Basin Supplement Forms and all required items listed therein at the correct
scales. The checklist includes a signed and notarized Operation and Maintenance
Agreement for the wet detention ponds as well as many other items. If all required
items are not included in the next submittal, your application will be returned.
The checklist is attached. Please note that we have attached a copy of the Operation &
Maintenance Agreement. However, due to the complications of the developing entity being a
non-profit government owned corporation, the document has not been executed, but we
anticipate execution within the next week. We will hand deliver copies to your office as soon
as they are received.
3. Please provide a table of elevations, areas, incremental volumes and accumulated
volumes for the ponds and forebays. This must include rows for key elevations (bottom,
sediment cleanout, permanent pool, temporary pool, etc.).
This information has been provided in the attached stormwater management report.
1410 Commonwealth Drive, Suite 1o1 Wilmington, North Carolina 28403 tel: [phone] fax:[phone]
www.withersravenel.com
WITHERS RAVENEL
ENGINEERS 1 PLANNERS I SURVEYORS
4. Please show the following items on the pond profiles:
a. The forebay invert, ponds invert and sediment clean-out elevations.
b. The correct side slopes: 10:1 for the vegetated shelf and 3:1 elsewhere.
c. The permanent and temporary pond elevations as well as any other relevant storage
elevations.
d. The size, length and slope of the outlet barrel.
This information has been added to the plan sheets.
5. The average depths provided are less than the required minimum of 3 feet. This depth
cannot include the 1' of sediment storage. Please revise the ponds to provide the
minimum depth or more. Please correct the errors in the calculation of average depth
in your resubmittal.
The calculations have been revised to exclude the sediment storage areas.
6. The forebay volumes must comprise 10 percent of the total volume of the BMP. None of
the four ponds have an appropriate forebay volume.
Per the BMP manual major design element #17, the forebays have been designed to be 20%
of the total permanent pool volumes, within a tolerance of 1.5%.
7. Planting plans for the ponds must be provided on the plans as per 10.3.7 of the BMP
manual.
Planting plans are included on the plan sheets.
8. Please provide the drawdown calculations for each pond.
This information has been added to the attached stormwater management report.
9. Please provide a soils test based on in-field borings conducted in the footprint of the
proposed wet detention ponds to document the SHWT elevation. Liners may be
required if it is well below the permanent pool elevations. See also 10.3.2 of the BMP
manual.
A note has been added to the BMP plan sheets for the evaluation of the seasonal high water
table at each BMP during construction and requiring clay liners if the seasonal high water
table is not within 6" of the permanent pool.
10. Please show details of all the pond outlets and associated energy dissipation devices.
This information has been added to the plan sheets.
1410 Commonwealth Drive, Suite 1o1 Wilmington, North Carolina 28403 tel: [phone] fax:[phone]
www.withersravenel.com
WITHERS RAVENEL
ENGINEERS I PLANNERS I SURVEYORS
11. Per the BMP Manual, the emergency spillway must be hardened with concrete, rip rap
or other appropriate material.
Each emergency spillway shall be lined with a permanent root reinforcement matting
(Enkamat 7020). This information is shown on the weir detail.
12. Please be sure that any changes are consistently reflected on all documents (plans,
calculations, supplement forms, etc.)
Noted.
13. For the Phase II portion of the site, you must provide a conceptual stormwater
management plan that includes the following:
a. A depiction of the drainage areas on the site.
b. An estimation of the percentage imperviousness associated with each of the drainage
areas.
c. A calculation of the water quality volume associated with each drainage area.
d. A depiction of the proposed BMP (state the type of BMP you plan to use) on the site
plan that is correctly sized based on the water quality volume.
This information has been added to Sheet SW3.0
Harnett Health Hospitals Comments:
Per conversation with Warren Sugg, Mulkey Engineers & Consultants, the site engineer
for the hospital, the hospital project has been placed on hold pending resolution of issues
not related to these documents. Therefore, we are not able to provide responses to these
comments at this time.
Please feel free to call us if you have any questions.
Sincerely,
Loftee Smith
Vice President
1410 Commonwealth Drive, Suite loi Wilmington, North Carolina 28403 tel: [phone] fax:[phone]
www.withersravenel.com
Y
WITHERS ` ' RAVEN EL
STORMWATER MANAGEMENT
REPORT
Brightwater Science & Technology Park
Harnett County, North Carolina
Prepared For:
Harnett County
Prepared By:
WITHERS & RAVENEL, INC
111 MacKenan Drive
Cary, North Carolina 27511
July 2010
W&R Project No. 2090050
f
BRIGHTWATER SCIENCE AND TECHNOLOGY PARK
STORMWATER MANAGEMENT REPORT
HARNETT COUNTY, NORTH CAROLINA
INTRODUCTION
Brightwater Science and Technology Park is a planned business development located in Harnett
County. The proposed 128-acre development will have a mix of office, institutional and retail uses
including the proposed Harnett Health Systems Hospital. The site lies directly across US401 from the
Harnett County Courthouse complex and is bounded to the west by the Matthews Road and to the
south by US401. The main entrance to the site will align with McKinney Parkway on US401. The site
lies within a WS-IV-PA watershed classification and is subject to Harnett County Water Supply
Watershed Management and Protection Ordinance. The purpose of this report is to establish the
minimum criteria for stormwater compliance that will apply to the initial infrastructure development
and the overall proposed stormwater management approach to meet the requirements.
STORMWATER MANAGEMENT REQUIREMENTS
Because the proposed development is within the Cape Fear River Basin, the site must meet the
requirements of the Harnett County Water Supply Watershed Management and Protection
Ordinance. This ordinance states: "Exception for Non-Residential Uses: Up to 10% of the protected
area may be developed for non-residential uses to seventy percent (70%) built-upon area on a
project by project basis. For the purpose of calculating built-upon area, total project area shall
include total acreage in the tract on which the project is to be developed." This project has been
designated for high intensity use as part of this exception. In reference to stream buffers this
ordinance requires: "a minimum of a loo hundred (loo) foot vegetative buffer for development
activities that exceed low density standards as established in this ordinance is required along all
perennial waters indicated on the most recent versions of the U.S.G.S 1:24,000 (7.5minute) scale
topographic maps, otherwise a minimum of thirty (30) foot buffer is required."
STORMWATER MANAGEMENT APPROACH
To meet the requirements of the Harnett County Water Supply Watershed Management and
Protection Ordinance, streams within the site will be subject to 30' stream buffers as no perennial
streams are indicated based on current U.S.G.S. mapping. In addition, an overall stormwater
management plan is proposed that will treat the runoff form the first one inch of rainfall and remove
a minimum of eighty-five percent (85%) of total suspended solids (TSS). Retention ponds are
proposed as the primary best management practice devices. Thirty foot filter strips will be required
at the release points for the first flush volume or the retention ponds shall be designed to treat for
ninety percent (go%) TSS removal.
Delineation of the drainage area to each BMP was based on existing terrain and a preliminary
estimate of storm drainage design. The impervious area for each drainage area was estimated
based on the preliminary illustrative master plan. To determine the surface area required for each
BMP, the volume of run-off created by one inch of rainfall (the "first flush") was calculated for the
drainage area. To calculate this water quality volume the Simple Method was used, as described in
the DWQ BMP Manual. This method uses a run-off coefficient to calculate the volume of run-off
given a depth of rainfall. The run-off coefficient is determined based on the percent imperviousness
of the drainage area. The minimum surface area necessary for the wet ponds was determined as
directed in the NC DWQ BMP manual.
The first phase of construction will be to establish the road network and infrastructure to support the
subsequent development of individual parcels. After completion of the various phases of grading
including the phase one road network, the wet ponds designed to treat each phase or parcel shall
be fully operational. All phases and parcels shall meet this stormwater management approach and
submit to NCDENR DWQ for approval prior to the start of construction.
Brightwater Science and Technology Park W&R Project 2090050
Stormwater Management Report March 2010
BRIGHTWATER SCIENCE AND TECHNOLOGY PARK
STORMWATER MANAGEMENT REPORT
HARNETT COUNTY, NORTH CAROLINA
PHASE 1
BMP WORKSHEETS
Brightwater Science and Technology Park W&R Project 2090050
Stormwater Management Report March 2010
Permit
477?54
NCDENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part 111) must be printed, filled out and submitted along with all of the required information.
(to be provided by DWQ)
ud r" ? E.
rte.
DUD E:;
I. PROJECT INFORMATION
Project name Brightwater Biotech Park
Contact person Loftee Smith
Phone number 919-469-3340
Date 5/1712010
Drainage area number Pond 1
Ill. DESIGN INFORMATION
Site Characteristics
Drainage area 213,008 ft2
Impervious area, post-development 108,900 ft2
% impervious 51.12 %
Design rainfall depth 1.0 in
Storage Volume: Non-SA Waters
Minimum volume required 9,055 ft3
Volume provided 11,896 ft3
Storage Volume: SA Waters
1.5' runoff volume n/a ft3
Pre-development 1-yr, 24-hr runoff ft3
Post-development 1-yr, 24-hr runoff ft3
Minimum volume required ft3
Volume provided ft3
Peak Flow Calculations
Is the pre/post control of the lyr 24hr storm peak flow required? N (Y or N)
1-yr, 24-hr rainfall depth 3.1 in
Rational C, pre-development (unitless)
Rational C, post-development (unitless)
Rainfall intensity: 1-yr, 24-hr storm in/hr
Pre-development 1-yr, 24-hr peak flow ft3/sec
Post-development 1-yr, 24-hr peak flow ft3/sec
Pre/Post 1-yr, 24-hr peak flow control ft3/sec
Elevations
Temporary pool elevation 168.37 fmsl
Permanent pool elevation 167.50 fmsl
SHWT elevation (approx. at the perm. pool elevation) fmsl
Top of 1Oft vegetated shelf elevation 168.00 fmsl
Bottom of 1Oft vegetated shelf elevation 167.00 fmsl
Sediment cleanout, top elevation (bottom of pond) 163.50 fmsl
Sediment cleanout, bottom elevation 162.50 fmsl
Sediment storage provided 1.00 ft
Is there additional volume stored above the state-required temp. pool?
Elevation of the top of the additional volume
OK
OK, volume provided is equal to or in excess of volume required.
(Y or N)
168.6 fmsl Insufficient. Must equal the temp. pool elev. previously entered.
Form SW401-Wet Detention Basin-Rev.e-9/17/09 Parts I. & II. Design Summary, Page 1 of 2
Permit No
(to be provided by DWQ)
Ill. DESIGN INFORMATION
Surface Areas
Area, temporary pool 11,424 ft2
Area REQUIRED, permanent pool 6,518 ft2
SA/DA ratio 3.06 (unitless)
Area PROVIDED, permanent pool, Apemyoo 8,262 ft` OK
Area, bottom of 1 Oft vegetated shelf, Abo, Shelf 5,951 ft`
Area, sediment cleanout, top elevation (bottom of pond), Abot_pond 1,735 ft`
Volumes
Volume, temporary pool 11,896 ft3 OK
Volume, permanent pool, Vpef,,,-pool 17,403 ft3
Volume, forebay (sum of forebays if more than one forebay) 3,221 ft3
Forebay % of permanent pool volume 18.5% % OK
SAIDA Table Data
Design TSS removal 90 %
Coastal SA/DA Table Used? N (Y or N)
Mountain/Piedmont SA/DA Table Used? Y (Y or N)
SA/DA ratio 3.06 (unitless)
Average depth (used in SA/DA table):
Calculation option 1 used? (See Figure 10-2b) N (Y or N)
Volume, permanent pool, Vperm " 17,403 ft'
Area provided, permanent pool, Ape--" 8,262 It`
Average depth calculated 2.11 ft Need 3 It min.
Average depth used in SA/DA, d.„ (Round to nearest 0.5ft) 3.0 It Insufficient. Check calculation.
Calculation option 2 used? (See Figure 10-2b) Y (Y or N)
Area provided, permanent pool, Ape--Pool 8,262 ft`
Area, bottom of 1Oft vegetated shelf, Abo, Shen 5,951 ft`
Area, sediment cleanout, top elevation (bottom of pond), Abol-pond 1,735 ft2
"Depth" (distance b/w bottom of 1Oft shelf and top of sediment) 3.50 ft
Average depth calculated 3.01 ft OK
Average depth used in SA/DA, day, (Round to nearest 0.5ft) 3.0 ft OK
Drawdown Calculations
Drawdown through orifice? Y (Y or N)
Diameter of orifice (if circular) 2.00 in
Area of orifice (if-non-circular) in2
Coefficient of discharge (CD) 0.60 (unitless)
Driving head (Ho) 1.10 ft
Drawdown through weir? N (Y or N)
Weir type (unitless)
Coefficient of discharge (C,,) (unitless)
Length of weir (L) ft
Driving head (H) It
Pre-development 1-yr, 24-hr peak flow ft3/sec
Post-development 1-yr, 24-hr peak flow ft3/sec
Storage volume discharge rate (through discharge orifice or weir) ft3/sec
Storage volume drawdown time 2.00 days OK, draws down in 2-5 days.
Additional Information
Vegetated side slopes 3 :1 OK
Vegetated shelf slope 10 :1 OK
Vegetated shelf width 10.0 It OK
Length of flowpath to width ratio 3 :1 OK
Length to width ratio 2.0 :1 OK
Trash rack for overflow & orifice? Y (Y or N) OK
Freeboard provided 1.2 ft OK
Vegetated filter provided? N (Y or N) OK
Recorded drainage easement provided? Y (Y or N) OK
Capures all runoff at ultimate build-out? Y (Y or N) OK
Drain mechanism for maintenance or emergencies is: pump
Form SW401-Wet Detention Basin-Rev.8-9/17/09 Parts I. & II. Design Summary, Page 2 of 2
Permit No
(to be provided by DWQ)
III. REQUIRED ITEMS CHECKLIST
Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will
result in a request for additional information. This will delay final review and approval of the project. Initial in the space provided to
indicate the following design requirements have been met. If the applicant has designated an agent, the agent may initial below. If a
requirement has not been met, attach justification.
Pagel Plan
Ils Sheet No.
'$W 2.-N
5 LO 11.1L

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FYI ) 'r L) LJ f

Plans (1" - 50' or larger) of the entire site showing:
Design at ultimate build-out,
- Off-site drainage (if applicable),
- Delineated drainage basins (include Rational C coefficient per basin),
Basin dimensions,
- Pretreatment system,
- High flow bypass system,
- Maintenance access,
Proposed drainage easement and public right of way (ROW),
- Overflow device, and
- Boundaries of drainage easement.
2. Partial plan (1" = 30' or larger) and details for the wet detention basin showing:
- Outlet structure with trash rack or similar,
- Maintenance access,
- Permanent pool dimensions,
- Forebay and main pond with hardened emergency spillway,
- Basin cross-section,
- Vegetation specification for planting shelf, and
- Filter strip.
3. Section view of the wet detention basin (1" = 20' or larger) showing:
- Side slopes, 3:1 or lower,
- Pretreatment and treatment areas, and
- Inlet and outlet structures.
4. If the basin is used for sediment and erosion control during construction, clean out of the basin is specified
on the plans prior to use as a wet detention basin.
5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay,
to verify volume provided.
6. A construction sequence that shows how the wet detention basin will be protected from sediment until the
entire drainage area is stabilized.
7. The supporting calculations.
8. A copy of the signed and notarized operation and maintenance (0&M) agreement.
9. A copy of the deed restrictions (if required).
10 A soils report that is based upon an actual field investigation, soil borings, and infiltration tests. County
soil maps are not an acceptable source of soils information.

Form SW401-Wet Detention Basin-Rev 8-9/17/09 Part 111. Required Items Checklist, Page 1 of 1
/ 4
Project Name: Brightwater Biotech Park
City/State: Lillington, NC
Project #: 2090050
Date: 17-May-10
Table 10-1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 90% Pollutant Removal
Efficiency in the Moutains and Piedmont
% Impervious Permanent Pool Dept h (feet)
Cover 3.0 4.0 5.0 6.0 7.0 8.0 9.0
10 0.90 0.80 0.80 0.60 0.50 0.50 0.40
20 1.50 1.30 1.10 1.00 0.90 0.80 0.80
30 1.90 1.80 1.70 1.40 1.30 1.00 1.00
40 2.50 2.30 2.00 1.80 1.60 1.50 1.30
50 3.00 2.80 2.50 2.00 1.90 1.70 1.60
60 3.50 3.20 2.80 2.50 2.20 1.90 1.80
70 4.00 3.70 3.30 2.80 2.50 2.20 2.00
80 4.50 4.10 3.80 3.30 2.80 2.60 2.30
90 5.00 4.50 4.00 3.50 3.00 2.80 2.60
Source: NCDENR/DWQ Stormwater Best Management Practices, pg. 10-9, July 2007
STORMWATER BMP POND 1

Land Use Area
(ac) % IA Imp. Area
(ac)
Impervious 2.5 100 2.5
Open Space 2.39 0 0.0

Totals 4.89 2.5
Total % Impervious Surface Area = 51.1 %
Surface Area of Permanent Pool:
Assumed depth = 3 feet
SA/DA ratio = 3.06 % From Table 10-1
Minimum pond surface area (SA) = (DA * SA/DA ratio)/100
SA = 0.149 acres
6510 sq. ft.
Normal pool elevation = 167.5 feet
Surface area provided = 0.190 acres
8262 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(1) where, Rv = Runoff coefficient, in./in.
I = Percent impervious
Rv = 0.51 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = 0.208 acre-ft
9055 cu.ft.
Water quality pool elevation required= 168.37 feet
Water quality pool elevation provided= 168.60 feet
Storage volume provided = 0.273 acre-ft
11896 cu. ft.
Additional storage volume provided = 2841 cu. ft.
a
Project Name: Brightwater Biotech Park
City/State: Lillington, NC
STORMWATER BMP - Pond 1
Orifice Calculator
Q =CdW(2gh)1(1/2)
Variables
WQ Volume: 0.207875 Acre-ft 9055.035 cf
Head (average): 1.10 ft 0.55 ft
Draw down time: 48 hrs 172800 s
Orifice Area = 0.014675 sq. ft 2.113165 sq. in
Orifice Diameter= 1.640295 in
Project #: 2090050
Date: 14-May-10
Constants
g = 32.2 ft/s2
Cd= 0.6
USE 2 INCH DIAMETER ORIFICE

STORMWATER BMP POND 1
Average Depth Calculator (BMP 1)
Normal Pool Elevation 167.5 ft
Bottom of Shelf 167 ft
Normal Pool Surface 8262 sf
Area at Bottom of Shelf 5951 sf
Area Bottom of Pond (main pond only) 1735 sf
Elevation (ft) Depth (ft) Area (sf) Incr. Volume (cf) Ac c. Volume (cf)
Normal Pool 167.5 0 8262 - -
Bottom of Shelf 167 0.5 5951 3553.25 3553.25
166 1.5 4753 5352 8905.25
165 2.5 3636 4194.5 13099.75
164 3.5 2606 3121 16220.75
Bottom of Pond* 163.5 4 2125 1182.75 17403.5
163.5 4 2125 0 17403.5
163.5 4 2125 0 17403.5
Max. Depth of Pond = 4 ft
Average Depth Calculations
Option 1 = 2.106451222 ft
Option 2 = 3.01 ft
Pond Design Average Depth = 3.00 ft (minimum 3')
Average Depth Calculation you should use: Option 2
Note: Average Depth must be greater than or equal to
average depth used to size surface area of pond
* Bottom of pond is the Sediment Clean out Top elevation
I
Forebay Design Tool (BMP 1)
Elevation (ft) Depth (ft) Area (sf) Incr. Volume (cf) Acc. Volume (cf)
Normal Pool 167.5 0 1733 - -
Bottom of Shelf 167 0.5 1096 707.25 707.25
166 1.5 862 979 1686.25
165 2.5 654 758 2444.25
164 3.5 470 562 3006.25
Bottom of Forbay 163.5 4 390 215 3221.25
Bottom of Sediment 162.5 5 248 319 3540.25 Not included in
forebay volume
Forebay Volume = 3221.25 cf
Pond Volume = 17403.5 cf
Forebay Percent = 18.51%
Status of Forebay Design: Forbay is sufficiently large
Pond Volume Calculation (BMP 1)
Elevation (ft) Depth (ft) Area (sf) Incr. Volume (cf) Acc. Volume (cf)
Normal Pool 167.5 0 8262 - -
Bottom of Shelf 167 0.5 5951 3553.25 3553.25
166 1.5 4753 5352 8905.25
165 2.5 3636 4194.5 13099.75
164 3.5 2606 3121 16220.75
Bottom of Pond 163.5 4 2125 1182.75 17403.5
Bottom of Sediment 162.5 5 2125 2125 19528.5 *not included in pond
volume
Pond Volume = 17403.5 cf
Permit
NCDENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part 111) must be printed, filled out and submitted along with all of the required information.
(to be provided by DWQ)
A - fi is
L PROJECT INFORMATION
Project name Brightwater Biotech Park
Contact person Loftee Smith
Phone number 919469-3340
Date b/1 //Zulu
Drainage area number Pond 2
II. DESIGN INFORMATION
Site Characteristics
Drainage area 100,623 ftz
Impervious area, post-development 31,363 fe
% impervious 31.17 %
Design rainfall depth 1.0 in
Storage Volume: Non-SA Waters
Minimum volume required 2,772 ft3 OK
Volume provided 7,928 ft3
OK, volume provided is equal to or in excess of volume required.
Storage Volume: SA Waters
1.5" runoff volume
Pre-development 1-yr, 24-hr runoff
Post-development 1-yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is the pre/post control of the lyr 24hr storm peak flow required?
1-yr, 24-hr rainfall depth
Rational C, pre-development
Rational C, post-development
Rainfall intensity: 1-yr, 24-hr storm
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Pre/Post 1-yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWT elevation (approx. at the perm. pool elevation)
Top of 1 Oft vegetated shelf elevation
Bottom of 1 Oft vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
Sediment cleanout, bottom elevation
Sediment storage provided
nla ft3
ft3
-ft3
to
ft3
N (Y or N)
3.1 in
(unitless)
(unitless)
in/hr
ft3/sec
ft3lsec
ft3lsec
161.95 fmsl
161.50 fmsl
fmsl
162.00 fmsl
161.00 fmsl
157.00 fmsl
156.00 fmsl
1.00 ft
Is there additional volume stored above the state-required temp. pool? Y (Y or N)
Elevation of the top of the additional volume 162.6 fmsl Insufficient. Must equal the temp. pool elev. previously entered.
Form SW401-Wet Detention Basin-Rev.8-9/17/09 Parts 1. & 11. Design Summary, Page 1 of 2
Permit No.
(to be provided by DWQ)
II. DESIGN' INFORMATION
Surface Areas
Area, temporary pool 7,634 ft2
Area REQUIRED, permanent pool 1,982 ft2
SA/DA ratio 1.97 (unitless)
Area PROVIDED, permanent pool, Apenp-l 5,408 ft` OK
Area, bottom of 1 Oft vegetated shelf, Abot shelf 3,707 ft`
Area, sediment cleanout, top elevation (bottom of pond), Abo and 732 ft`
Volumes
Volume, temporary pool 7,928 ft3 OK
Volume, permanent pool, Vperm-Poo 10,915 ft3
Volume, forebay (sum of forebays if more than one forebay) 2,299 ft3
Forebay % of permanent pool volume 21.1% % OK
SAIDA Table Data
Design TSS removal 90 %
Coastal SAIDA Table Used? N (Y or N)
Mountain/Piedmont SAIDA Table Used? Y (Y or N)
SA/DA ratio 1.97 (unitless)
Average depth (used in SA/DA table):
Calculation option 1 used? (See Figure 10-2b) N (Y or N)
Volume, permanent pool, Vpem-pm 10,915 ft'
Area provided, permanent pool, Apenp 5,408 ft2
Average depth calculated 2.01 It Need 3 ft min.
Average depth used in SA/DA, de,„ (Round to nearest 0.5ft) 3.0 ft Insufficient. Check calculation.
Calculation option 2 used? (See Figure 10-2b) Y (Y or N)
Area provided, permanent pool, Apen po, 5,408 ft`
Area, bottom of 1Oft vegetated shelf, Abot shelf 3,707 ft`
Area, sediment cleanout, top elevation (bottom of pond), Abotj?nd 732 ft2
"Depth" (distance b/w bottom of 1Oft shelf and top of sediment) 4.00 ft
Average depth calculated 3.12 ft OK
Average depth used in SA/DA, d.„ (Round to nearest 0.5ft) 3.0 ft OK
Drawdown Calculations
Drawdown through orifice? Y (Y or N)
Diameter of orifice (if circular) 1.00 in
Area of orifice (if-non-circular) in2
Coefficient of discharge (Cc) 0.60 (unitless)
Driving head (Ho) 1.10 ft
Drawdown through weir? N (Y or N)
Weir type (unitless)
Coefficient of discharge (CW) (unitless)
Length of weir (L) ft
Driving head (H) ft
Pre-development 1-yr, 24-hr peak flow ft3/sec
Post-development 1-yr, 24-hr peak flow ft3/sec
Storage volume discharge rate (through discharge orifice or weir) ft3/sec
Storage volume drawdown time 2.00 days OK, draws down in 2-5 days.
Additional Information
Vegetated side slopes 3 :1 OK
Vegetated shelf slope 10 :1 OK
Vegetated shelf width 10.0 It OK
Length of flowpath to width ratio 3 :1 OK
Length to width ratio 2.0 :1 OK
Trash rack for overflow & orifice? Y (Y or N) OK
Freeboard provided 1.1 ft OK
Vegetated filter provided? N (Y or N) OK
Recorded drainage easement provided? Y (Y or N) OK
Capures all runoff at ultimate build-out? Y (Y or N) OK
Drain mechanism for maintenance or emergencies is: pump
Form SW401-Wet Detention Basin-Rev.8-9/17/09 Parts I. & II. Design Summary, Page 2 of 2
Permit No
(to be provided by DWQ)
III. REQUIRED ITEMS CHECKLIST
Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will
result in a request for additional information. This will delay final review and approval of the project. Initial in the space provided to
indicate the following design requirements have been met. If the applicant has designated an agent, the agent may initial below. If a
requirement has not been met, attach justification.
Pagel Plan
niti,als Sheet No.
"
'
1. Plans (1
- 50
or larger) of the entire site showing:
• Design at ultimate build-out,
Off-site drainage (if applicable),
D
li
e
neated drainage basins (include Rational C coefficient per basin),
Basin dimensions,
Pretreatment system,
High flow bypass system,
Maintenance access,
Proposed drainage easement and public right of way (ROW),
Overflow device, and
Boundaries of drainage easement.
"
'
2. Partial plan (1
= 30
or larger) and details for the wet detention basin showing:
- Outlet structure with trash rack or similar,
- Maintenance access,
- Permanent pool dimensions,
- Forebay and main pond with hardened emergency spillway,
- Basin cross-section,
- Vegetation specification for planting shelf, and
/ - Filter strip.
3. Section view of the wet detention basin (1" = 20' or larger) showing:
Side slopes, 3:1 or lower,
Pretreatment and treatment areas, and
Inlet and outlet structures.

4. If the basin is used for sediment and erosion control during construction, clean out of the basin is specified
r on the plans prior to use as a wet detention basin.
5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay,
a
C to verify volume provided.
6
A
.
construction sequence that shows how the wet detention basin will be protected from sediment until the
entire drainage area is stabilized.
7
Th
ti
l
l
ti
` .
e suppor
ng ca
cu
a
ons.
' l ?ADr G
8. A copy of the signed and notarized operation and maintenance (0&M) agreement.
vl . 9. A copy of the deed restrictions (if required).
.d - 10
A
il
t th
t i
b
d
l fi
t
ld i
• .
so
s repor
a
s
ase
upon an ac
ua
e
nvestigation, soil borings, and infiltration tests. County
soil maps are not an acceptable source of soils information.
Form SW401-Wet Detention Basin-Rev.8-9/17/09 Part III. Required Items Ch(cklist, Page 1 of 1
t i
Project Name: Brightwater Biotech Park
City/State: Lillington, NC
Project #: 2090050
Date: 17-May-10
Table 10-1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 90% Pollutant Removal
Efficient in the Moutains and Piedmont
% Impervious Permanent Pool Depth (feet)
Cover 3.0 4.0 5.0 6.0 7.0 8.0 9.0
10 0.90 0.80 0.80 0.60 0.50 0.50 0.40
20 1.50 1.30 1.10 1.00 0.90 0.80 0.80
30 1.90 1.80 1.70 1.40 1.30 1.00 1.00
40 2.50 2.30 2.00 1.80 1.60 1.50 1.30
50 3.00 2.80 2.50 2.00 1.90 1.70 1.60
60 3.50 3.20 2.80 2.50 2.20 1.90 1.80
70 4.00 3.70 3.30 2.80 2.50 2.20 2.00
80 4.50 4.10 3.80 3.30 2.80 2.60 2.30
L 90 5.00 4.50 4.00 3.50 3.00 2.80 2.60
Source: NCDENR/DWQ Stormwater Best Management Practices, pg. 10-9, July 2007
STORMWATER BMP POND 2

Land Use Area
(ac) % IA Imp. Area
(ac)
Impervious 0.72 100 0.7
Open Space 1.59 0 0.0

Totals 2.31 0.7
Total % Impervious Surface Area = 31.2 %
Surface Area of Permanent Pool:
Assumed depth = 3 feet
SA/DA ratio = 1.97 % From Table 10-1
Minimum pond surface area (SA) _ (DA * SA/DA ratio)/100
SA = 0.046 acres
1982 sq. ft.
Normal pool elevation = 161.5 feet
Surface area provided = 0.124 acres
5408 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(1) where, Rv = Runoff coefficient, in./in.
I = Percent impervious
Rv = 0.33 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = 0.064 acre-ft
2772 cu. ft.
Water quality pool elevation required= 161.95 feet
Water quality pool elevation provided= 162.60 feet
Storage volume provided = 0.182 acre-ft
7928 cu. ft.
Additional storage volume provided = 5156 cu. ft.

Project Name: Brightwater Biotech Park
City/State: Lillington, NC
STORMWATER BMP - Pond 2
Orifice Calculator
Q =Cd*A*(2gh)"(112)
Variables
WQ Volume: 0.063625 Acre-ft 2771.505 cf
Head (average): 1.10 ft 0.55 ft
Draw down time: 48 hrs 172800 s
Orifice Area = 0.004492 sq. ft 0.646783 sq. in
Orifice Diameter= 0.907475 in
USE 1 INCH DIAMETER ORIFICE
Project #: 2090050
Date: 14-May-10
Constants
g = 32.2 ft/s2
Cd= 0.6

STORMWATER BMP POND 2
Average Depth Calculator (BMP 2)
Normal Pool Elevation 161.5 ft
Bottom of Shelf 161 ft
Normal Pool Surface 5408 sf
Area at Bottom of Shelf 3707 sf
Area Bottom of Pond (main pond only) 732 sf
Elevation (ft) Depth (ft) Area (sf) Incr. Volume (cf) Acc. Volume (cf)
Normal Pool 161.5 0 5408 - -
Bottom of Shelf 161 0.5 3707 2278.75 2278.75
160 1.5 2865 3286 5564.75
159 2.5 2104 2484.5 8049.25
158 3.5 1448 1776 9825.25
Bottom of Pond* 157 4.5 732- 1090 10915.25
157 4.5 732 0 10915.25
157 4.5 732 0 10915.25
Max. Depth of Pond = 4.5 ft
Average Depth Calculations
Option 1 = 2.018352441 ft
Option 2 = 3.12 ft
Pond Design Average Depth = 3.00 ft (minimum 3')
Average Depth Calculation you should use: Option 2
Note: Average Depth must be greater than or equal to
average depth used to size surface area of pond
* Bottom of pond is the Sediment Clean out Top elevation

Forebay Design Tool (BMP 2)
Elevation (ft) Depth (ft) Area (sf)
Normal Pool 161.5 0 1478
Bottom of Shelf 161 0.5 868
160 1.5 656
159 2.5 469
Bottom of Forbay 158 3.5 307
Bottom of Sediment ` 157 4.5 173
Incr. Volume (cf) Acc. Volume (cf)
586.5 586.5
762 1348.5
562.5 1911
388 2299
240 2539
Forebay Volume = 2299 cf
Pond Volume = 10915.25 cf
Forebay Percent =
Status of Forebay Design
*not included in
forebay volume
21.06%
Forbay is sufficiently large
Pond Volume Calculation (BMP 2)
Elevation (ft) Depth (ft) Area (sf) Incr. Volume (cf) Acc. Volume (cf)
Normal Pool 161.5 0 5408 - -
Bottom of Shelf 161 0.5 3707 2278.75 2278.75
160 1.5 2865 3286 5564.75
159 2.5 2104 2484.5 8049.25
158 3.5 1448 1776 9825.25
Bottom of Pond 157 4.5 732 1090 10915.25
Bottom of Sediment 156 5.5 401 566.5 11481.75 *not included in pond
volume
Pond Volume = 10915.25 cf
Permit No
a
NCDENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part III) must be printed, filled out and submitted along with all of the required information.
(to be provided by DWQ)
A ?,?..
I. PROJECT INFORMATION
Project name Brightwater Biotech Park
Contact person Loftee Smith
Phone number 919469-3340
Date 5/17/2010
Drainage area number Pond 3
II. DESIGN INFORMATION
Site Characteristics
Drainage area 229,996 ft2
Impervious area, post-development 69,696 ft2
% impervious 30.30 %
Design rainfall depth 1.0 in
Storage Volume: Non-SA Waters
Minimum volume required 6,186 ft3
Volume provided 11,992 ft3
Storage Volume: SA Waters
1.5' runoff volume n/a ft3
Pre-development 1-yr, 24-hr runoff ft3
Post-development 1-yr, 24-hr runoff ft3
Minimum volume required ft3
Volume provided ft3
Peak Flow Calculations
Is the pre/post control of the lyr 24hr storm peak flow required? N (Y or N)
1-yr, 24-hr rainfall depth 3.1 in
Rational C, pre-development (unitless)
Rational C, post-development (unitless)
Rainfall intensity: 1-yr, 24-hr storm in/hr
Pre-development 1-yr, 24-hr peak flow ft3/sec
Post-development 1-yr, 24-hr peak flow ft3/sec
Pre/Post 1-yr, 24-hr peak flow control ft3/sec
Elevations
Temporary pool elevation 167.11 fmsl
Permanent pool elevation 166.50 fmsl
SHWT elevation (approx. at the perm. pool elevation) fmsl
Top of 1Oft vegetated shelf elevation 167.00 fmsl
Bottom of 1 Oft vegetated shelf elevation 166.00 fmsl
Sediment cleanout, top elevation (bottom of pond) 162.00 fmsl
Sediment cleanout, bottom elevation 161.00 fmsl
Sediment storage provided 1.00 ft
Is there additional volume stored above the state-required temp. pool?
Elevation of the top of the additional volume
OK
OK, volume provided is equal to or in excess of volume required.
(Y or N)
167.6 fmsl Insufficient. Must equal the temp. pool elev. previously entered.
Form SW401-Wet Detention Basin-Rev.8-9/17/09 Parts I. & It. Design Summary, Page 1 of 2
Permit No
(to be provided by DWQ)
II. DESIGN INFORMATION
Surface Areas
Area, temporary pool 11,420 ft2
Area REQUIRED, permanent pool 4,416 ft2
SA/DA ratio 1.92 (unitless)
Area PROVIDED, permanent pool, Apem,_pod 8,683 ft2 OK
Area, bottom of 1 Oft vegetated shelf, Abot shelf 6,436 ft2
Area, sediment cleanout, top elevation (bottom of pond), Abot_pond 1,827 ft`
Volumes
Volume, temporary pool 11,992 ft3 OK
Volume, permanent pool, Vpen_pwi 20,226 ft3
Volume, forebay (sum of forebays if more than one forebay) 3,988 ft3
Forebay % of permanent pool volume 19.7% % OK
SA/DA Table Data
Design TSS removal 90 %
Coastal SA/DA Table Used? N (Y or N)
Mountain/Piedmont SA/DA Table Used? Y (Y or N)
SA/DA ratio 1.92 (unitless)
Average depth (used in SA/DA table):
Calculation option 1 used? (See Figure 10-2b) N (Y or N)
Volume, permanent pool, Vperm_pod 20,226 ft'
Area provided, permanent pool, Apenpoo 8,683 ft2
Average depth calculated 2.33 ft Need 3 ft min.
Average depth used in SA/DA, dav, (Round to nearest 0.5ft) 3.0 ft Insufficient. Check calculation.
Calculation option 2 used? (See Figure 10-2b) Y (Y or N)
Area provided, permanent pool, Apenpod 8,683 ft2
Area, bottom of 1Oft vegetated shelf, Abot shelf 6,436 ft2
Area, sediment cleanout, top elevation (bottom of pond), Abot pond 1,827 ft2
"Depth" (distance blw bottom of 1Oft shelf and top of sediment) 4.00 ft
Average depth calculated 3.32 ft OK
Average depth used in SA/DA, ds, (Round to nearest 0.5ft) 3.0 ft Insufficient. Check calculation.
Drawdown Calculations
Drawdown through orifice? Y (Y or N)
Diameter of orifice (if circular) 1.00 in
Area of orifice (if-non-circular) in'
Coefficient of discharge (CD) 0.60 (unitless)
Driving head (Ho) 1.10 ft
Drawdown through weir? N (Y or N)
Weir type (unitless)
Coefficient of discharge (C.) (unitless)
Length of weir (L) It
Driving head (H) It
Pre-development 1-yr, 24-hr peak flow ft3/sec
Post-development 1-yr, 24-hr peak flow ft3/sec
Storage volume discharge rate (through discharge orifice or weir) ft3/sec
Storage volume drawdown time 2.00 days OK, draws down in 2-5 days.
Additional Information
Vegetated side slopes 3 :1 OK
Vegetated shelf slope 10 :1 OK
Vegetated shelf width 10.0 ft OK
Length of flowpath to width ratio 3 :1 OK
Length to width ratio 2.0 :1 OK
Trash rack for overflow & orifice? Y (Y or N) OK
Freeboard provided 1.1 ft OK
Vegetated filter provided? N (Y or N) OK
Recorded drainage easement provided? Y (Y or N) OK
Capures all runoff at ultimate build-out? Y (Y or N) OK
Drain mechanism for maintenance or emergencies is: pump
Form SW401-Wet Detention Basin-Rev.8-9/17/09 Parts I. & II. Design Summary, Page 2 of 2
Permit N
(to be provided by DWQ)
III. REQUIRED ITEMS CHECKLIST
Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will
result in a request for additional information. This will delay final review and approval of the project. Initial in the space provided to
indicate the following design requirements have been met. If the applicant has designated an agent, the agent may initial below. If a
requirement has not been met, attach justification.
Pagel Plan
Initials Sheet No.
y 1. Plans (1" - 50' or larger) of the entire site showing:
- Design at ultimate build-out,
- Off-site drainage (if applicable),
'• - Delineated drainage basins (include Rational C coefficient per basin),
- Basin dimensions,
- Pretreatment system,
- High flow bypass system,
- Maintenance access,
- Proposed drainage easement and public right of way (ROW),
- Overflow device, and
- Boundaries of drainage easement.

l 2. Partial plan (1" = 30' or larger) and details for the wet detention basin showing:
- Outlet structure with trash rack or similar,
- Maintenance access,
- Permanent pool dimensions,
- Forebay and main pond with hardened emergency spillway,
- Basin cross-section,
- Vegetation specification for planting shelf, and
?-?- ? U ?
f I• -Filter strip.

3. Section view of the wet detention basin (1" = 20' or larger) showing:
Side slopes, 3:1 or lower,
- Pretreatment and treatment areas, and
Inlet and outlet structures.
l '_°j 4. If the basin is used for sediment and erosion control during construction, clean out of the basin is specified
on the plans prior to use as a wet detention basin.
5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay,
! to verify volume provided.
6. A construction sequence that shows how the wet detention basin will be protected from sediment until the
entire drainage area is stabilized.
&'64 7. The supporting calculations.
??V "`? Qa? 8. A copy of the signed and notarized operation and maintenance (0&M) agreement.
)' I 9. A copy of the deed restrictions (if required).
t 10. A soils report that is based upon an actual field investigation, soil borings, and infiltration tests. County
soil maps are not an acceptable source of soils information.
Form SW401-Wet Detention Basin-Rev.8-9/17/09 Part III. Required Items Checklist, Page 1 of 1

Project Name: Brightwater Biotech Park
City/State: Lillington, NC
Project #: 2090050
Date: 17-May-10
Table 10-1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 90% Pollutant Removal
Efficiency in the Moutains and Piedmont
% Impervious Permanent Pool Dept h (feet)
Cover 3.0 4.0 5.0 6.0 7.0 8.0 9.0
10 0.90 0.80 0.80 0.60 0.50 0.50 0.40
20 1.50 1.30 1.10 1.00 0.90 0.80 0.80
30 1.90 1.80 1.70 1.40 1.30 1.00 1.00
40 2.50 2.30 2.00 1.80 1.60 1.50 1.30
50 3.00 2.80 2.50 2.00 1.90 1.70 1.60
60 3.50 3.20 2.80 2.50 2.20 1.90 1.80
70 4.00 3.70 3.30 2.80 2.50 2.20 2.00
80 4.50 4.10 3.80 3.30 2.80 2.60 2.30
90 5.00 4.50 4.00 3.50 3.00 2.80 2.60
Source: NCDENR/DWQ Stormwater Best Management Practices, pg. 10-9, July 2007
STORMWATER BMP POND 3

Land Use Area
(ac) % IA Imp. Area
(ac)
Impervious 1.6 100 1.6
Open Space 3.68 0 0.0

Totals 5.28 1.6
Total % Impervious Surface Area = 30.3 %
Surface Area of Permanent Pool:
Assumed depth = 3 feet
SA/DA ratio = 1.92 % From Table 10-1
Minimum pond surface area (SA) = (DA * SA/DA ratio)/100
SA = 0.101 "acres
4412 sq. ft.
Normal pool elevation = 166.5 feet
Surface area provided = 0.199 acres
8683 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(1) where, Rv = Runoff coefficient, in./in.
I = Percent impervious
Rv = 0.32 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = 0.142 acre-ft
6186 cu. ft.
Water quality pool elevation required= 167.11 feet
Water quality pool elevation provided= 167.60 feet
Storage volume provided = 0.275 acre-ft
11992 Cu. ft.
Additional storage volume provided = 5806 cu. ft.
I Y
Project Name: Brightwater Biotech Park
City/State: Lillington, NC
STORMWATER BMP - Pond 3
Orifice Calculator
Q =Cd*A*(2gh)^(1/2)
Variables
WQ Volume:
Head (average):
Draw down time:
Orifice Area= 0.010024 sq. ft
0.142 Acre-ft 6185.52 cf
1.10 ft 0.55 ft
48 hrs 172800 s
Orifice Diameter = 1.355704 in
USE 1 INCH DIAMETER ORIFICE
1.443509 sq. in
Project #: 2090050
Date: 14-May-10
Constants
g = 32.2 ft/sz
Cd= 0.6

STORMWATER BMP POND 3
Average Depth Calculator (BMP 3)
Normal Pool Elevation 166.5 ft
Bottom of Shelf 166 ft
Normal Pool Surface 8683 sf
Area at Bottom of Shelf 6436 sf
Area Bottom of Pond (main pond only) 1827 sf
Elevation (ft) Depth (ft) Area (sf) Incr. Volume (cf) Acc. Volume (cf)
Normal Pool 166.5 0 8683 - -
Bottom of Shelf 166 0.5 6436 3779.75 3779.75
165 1.5 5215 5825.5 9605.25
164 2.5 4072 4643.5 14248.75
163 3.5 3028 3550 17798.75
Bottom of Pond* 162 4.5 1827 2427.5 20226.25
162 4.5 1827 0 20226.25
162 4.5 1827 0 20226.25
Max. Depth of Pond = 4.5 ft
Average Depth Calculations
Option 1 = 2.329408039 ft
Option 2 = 3.32 ft
Pond Design Average Depth = 3.00
Average Depth Calculation you should use:
ft (minimum 3')
Option 2
Note: Average Depth must be greater than or equal to
average depth used to size surface area of pond
* Bottom of pond is the Sediment Clean out Top elevation
STORMWATER BMP POND 3
Forebay Design Tool (BMP 3)
Elevation (ft) Depth (ft) Area (sf) Incr. Volume (cf) Acc. Volume (cf)
Normal Pool 166.5 0 2333 - -
Bottom of Shelf 166 0.5 1519 963 963
165 1.5 1165 1342 2305
164 2.5 835 1000 3305
Bottom of Forbay 163 3.5 532 683.5 3988.5
Bottom of Sediment 162 4.5 256 394 4382.5 *not included in
forebay volume
Forebay Volume = 3988.5 cf
Pond Volume = 20226.25 cf
Forebay Percent = 19.72%
Status of Forebay Design: Forbay is sufficiently large
Pond Volume Calculation (BMP 3)
Elevation (ft) Depth (ft) Area (sf) Incr. Volume (cf) Acc. Volume (cf)
Normal Pool 166.5 0 8683 - -
Bottom of Shelf 166 0.5 6436 3779.75 3779.75
165 1.5 5215 5825.5 9605.25
164 2.5 4072 4643.5 14248.75
163 3.5 3028 3550 17798.75
Bottom of Pond 162 4.5 1827 2427.5 20226.25
Bottom of Sediment 161 5.5 1222 1524.5 21750.75 *not included in pond
volume
Pond Volume = 20226.25 cf
Permit No
t
NC©ENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part III) must be printed, filled out and submitted along with all of the required information.
(to be provided by DWO)

1. PROJECT INFORMATION
Project name Brightwater Biotech Park
Contact person Loftee Smith
Phone number 919-469-3340
Date 5/1712010
Drainage area number Pond 4
II. DESIGN INFORMATION
Site Characteristics
Drainage area 237,402 ftz
Impervious area, post-development 154,638 ft2
% impervious 65.14 %
Design rainfall depth 1.0 in
Storage Volume: Non-SA Waters
Minimum volume required 12,587 ft3
Volume provided 15,943 ft3
Storage Volume: SA Waters
1.5" runoff volume n/a ft3
Pre-development 1-yr, 24-hr runoff ft3
Post-development 1-yr, 24-hr runoff ft3
Minimum volume required ft3
Volume provided ft3
Peak Flow Calculations
Is the pre/post control of the lyr 24hr storm peak flow required? N (Y or N)
1-yr, 24-hr rainfall depth 3.1 in
Rational C, pre-development (unitless)
Rational C, post-development (unitless)
Rainfall intensity: 1-yr, 24-hr storm in/hr
Pre-development 1-yr, 24-hr peak flow ft3/sec
Post-development 1-yr, 24-hr peak flow ft3/sec
Pre/Post 1-yr, 24-hr peak flow control ft3/sec
Elevations
Temporary pool elevation 159.54 fmsl
Permanent pool elevation 158.50 fmsl
SHWT elevation (approx. at the perm. pool elevation) fmsl
Top of 1Oft vegetated shelf elevation 159.00 fmsl
Bottom of 10ft vegetated shelf elevation 158.00 fmsl
Sediment cleanout, top elevation (bottom of pond) 154.50 fmsl
Sediment cleanout, bottom elevation 153.50 fmsl
Sediment storage provided 1.00 ft
Is there additional volume stored above the state-required temp. pool?
Elevation of the top of the additional volume
OK
OK, volume provided is equal to or in excess of volume required.
(Y or N)
159.8 fmsl Insufficient. Must equal the temp. pool elev. previously entered.
Form SW401-Wet Detention Basin-Rev.8-9/17/09 Parts I. & II. Design Summary, Page 1 of 2
Permit
(to be provided by DWQ)
III. REQUIRED ITEMS CHECKLIST
Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will
result in a request for additional information. This will delay final review and approval of the project. Initial in the space provided to
indicate the following design requirements have been met. If the applicant has designated an agent, the agent may initial below. If a
requirement has not been met, attach justification.
Pagel Plan
Initials Sheet No.
1. Plans (1" - 50' or larger) of the entire site showing:
Design at ultimate build-out,
Off-site drainage (if applicable),
- Delineated drainage basins (include Rational C coefficient per basin),
Basin dimensions,
Pretreatment system,
High flow bypass system,
- Maintenance access,
Proposed drainage easement and public right of way (ROW),
Overflow device, and
Boundaries of drainage easement.
1 t t
+ - I • 2. Partial plan (1" = 30' or larger) and details for the wet detention basin showing:
Outlet structure with trash rack or similar,
Maintenance access,
Permanent pool dimensions,
Forebay and main pond with hardened emergency spillway,
Basin cross-section,
Vegetation specification for planting shelf, and
Filter strip.
"
'
3. Section view of the wet detention basin (1
= 20
or larger) showing:
Side slopes, 3:1 or lower,
Pretreatment and treatment areas, and
Inlet and outlet structures.
4. If the basin is used for sediment and erosion control during construction, clean out of the basin is specified
on the plans prior to use as a wet detention basin.
5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay,
to verify volume provided.
W ` t • 6. A construction sequence that shows how the wet detention basin will be protected from sediment until the
` entire drainage area is stabilized.
fi'"EC 7. The supporting calculations.
l 8. A copy of the signed and notarized operation and maintenance (0&M) agreement.
9. A copy of the deed restrictions (if required).
1
0. A soils report that is based upon an actual field investigation, soil borings, and infiltration tests. County
soil maps are not an acceptable source of soils information.
Form SW401-Wet Detention Basin-Rev.8-9/17/09 Part III. Required Items Checklist, Page 1 of 1

Project Name: Brightwater Biotech Park
City/State: Lillington, NC
Project #: 2090050
Date: 17-May-10
Table 10-1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 90% Pollutant Removal
Efficient in the Moutains and Piedmont
% Impervious Permanent Pool Dept h (feet)
Cover 3.0 4.0 5.0 6.0 7.0 8.0 9.0
10 0.90 0.80 0.80 0.60 0.50 0.50 0.40
20 1.50 1.30 1.10 1.00 0.90 0.80 0.80
30 1.90 1.80 1.70 1.40 1.30 1.00 1.00
40 2.50 2.30 2.00 1.80 1.60 1.50 1.30
50 3.00 2.80 2.50 2.00 1.90 1.70 1.60
60 3.50 3.20 2.80 2.50 2.20 1.90 1.80
70 4.00 3.70 3.30 2.80 2.50 2.20 2.00
80 4.50 4.10 3.80 3.30 2.80 2.60 2.30
90 5.00 4.50 4.00 3.50 3.00 2.80 2.60
Source: NCUtNK/UW(j Stonnwater best Management Practices, pg. 10-9, July 2007
STORMWATER BMP POND 4

Land Use Area
(ac) % IA Imp. Area
(ac)
Impervious 3.55 100 3.6
Open Space 1.9 0 0.0

Totals
116- 5.45 3.6
Total % Impervious Surface Area = 65.1 %
Surface Area of Permanent Pool:
Assumed depth = 3 feet
SA/DA ratio = 3.76 % From Table 10-1
Minimum pond surface area (SA) _ (DA * SA/DA ratio)/100
SA = 0.205 acres
8919 sq. ft.
Normal pool elevation = 158.5 feet
Surface area provided = 0.231 acres
10078 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(1) where, Rv = Runoff coefficient, in./in.
I = Percent impervious
Rv = 0.64 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = 0.289 acre-ft
12587 cu. ft.
Water quality pool elevation required= 159.54 feet
Water quality pool elevation provided= 159.80 feet
Storage volume provided = 0.366 acre-ft
15943 cu. ft.
Additional storage volume provided = 3356 cu. ft.
A ?
Project Name: Brightwater Biotech Park
City/State: Lillington, NC
STORMWATER BMP - Pond 4
Orifice Calculator
Q =Cd*A*(2gh)"(1/2)
Variables
WQ Volume: 0.288958 Acre-ft 12587.03 cf
Head (average): 1.30 ft 0.65 ft
Draw down time: 48 hrs 172800 s
Orifice Area = 0.018764 sq. ft 2.702035 sq. in
Orifice Diameter= 1.854816 in
USE 2 INCH DIAMETER ORIFICE
Project #: 2090050
Date: 14-May-10
Constants
g = 32.2 ft/sZ
Cd= 0.6

STORMWATER BMP POND 4
Average Depth Calculator (BMP 4)
Normal Pool Elevation 158.5 ft
Bottom of Shelf 158 ft
Normal Pool Surface 10078 sf
Area at Bottom of Shelf 7643 sf
Area Bottom of Pond (main pond only) 2570 sf
Elevation (ft) Depth (ft) Area (sf) Incr. Volume (cf) Acc. Volume (cf)
Normal Pool 158.5 0 10078 - -
Bottom of Shelf 158 0.5 7643 4430.25 4430.25
157 1.5 6295 6969 11399.25
156 2.5 5024 5659.5 17058.75
155 3.5 3857 4440.5 21499.25
Bottom of Pond* 154.5 4 2570 1606.75 23106
154.5 4 2570 0 23106
154.5 4 2570 0 23106
Max. Depth of Pond = 4 ft
Average Depth Calculations
Option 1 = 2.292716809 ft
Option 2 = 3.11 ft
Pond Design Average Depth = 3.00 ft (minimum T)
Average Depth Calculation you should use: Option 2
Note: Average Depth must be greater than or equal to
average depth used to size surface area of pond
* Bottom of pond is the Sediment Clean out Top elevation
STORMWATER BMP POND 4
Forebay Design Tool (BMP 4)
Elevation (ft) Depth (ft) Area (sf) Incr. Volume (cf) Acc. Volume (cf)
Normal Pool 158.5 0 2424 - -
Bottom of Shelf 158 0.5 1674 1024.5 1024.5
157 1.5 1375 1524.5 2549
156 2.5 1100 1237.5 3786.5
Bottom of Forbay 155 3.5 849 974.5 4761
Bottom of Sediment 154 4.5 630 739.5 5500.5 *not included in
forebay volume
Forebay Volume = 4761 cf
Pond Volume = 23106 cf
Forebay Percent = 20.61%
Status of Forebay Design: Forbay is sufficiently large
Pond Volume Calculation (BMP 4)
Elevation (ft) Depth (ft) Area (sf) Incr. Volume (cf) Acc. Volume (cf)
Normal Pool 158.5 0 10078 - -
Bottom of Shelf 158 0.5 7643 4430.25 4430.25
157 1.5 6295 6969 11399.25
156 2.5 5024 5659.5 17058.75
155 3.5 3857 4440.5 21499.25
Bottom of Pond 154.5 4 2570 1606.75 23106
Bottom of Sediment 153.5 5 2570 2570 25676 *not included in pond
volume
Pond Volume = 23106 cf
BRIGHTWATER SCIENCE AND TECHNOLOGY PARK
STORMWATER MANAGEMENT REPORT
HARNETT COUNTY, NORTH CAROLINA
PHASE 1
POND PACK REPORT
Brightwater Science and Technology Park W&R Project 2090050
Stormwater Management Report March 2010
Type.... Master Network Summary Page 2.01
Name.... Watershed
File.... K:\09\09-0050\090050-Brightwater Ph II\H-H\Pond Pack\Brightwater Biotech Park 05-
MASTER DESIGN STORM SUMMARY
Network Storm Collection: Dunn NOAA 14, 24
Total
Depth
Return Event in
2 3.7000
10 5.5800
25 6.7500
100 8.7300
1 3.0500
Rainfall
Type
----------------
Time-Depth Curve
Time-Depth Curve
Time-Depth Curve
Time-Depth Curve
Synthetic Curve
RNF ID
Dunn 2-yr, 24-hr
Dunn 10-yr, 24hr
Dunn 25-yr, 24hr
Dunn 100-yr, 24h
TypeII 24hr
MASTER NETWORK SUMMARY
SCS Unit Hydrograph Method
(*Node=Outfall; +Node=Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt)
Return HYG Vol Qpeak
Node ID Type Event ac-ft Trun
------ hrs
-----------
BMP 1 ------
IN ----
POND ------
2 ----
--
1.075 ---------
12.1000
BMP 1 IN POND 10 1.809 12.1000
BMP 1 IN POND 25 2.274 12.1000
BMP 1 IN POND 100 3.068 12.1000
BMP 1 IN POND 1 .827 11.9000
BMP 1 OUT POND 2 1.070 12.1500
BMP 1 OUT POND 10 1.805 12.1500
BMP 1 OUT POND 25 2.270 12.1500
BMP 1 OUT POND 100 3.063 12.1500
BMP 1 OUT POND 1 .823 12.0500
BMP2 IN POND 2 .438 12.1000
BMP2 IN POND 10 .773 12.1000
BMP2 IN POND 25 .987 12.1000
BMP2 IN POND 100 1.356 12.1000
BMP2 IN POND 1 .328 11.9000
Max
Qpeak Max WSEL Pond Storage
cfs ft ac-ft
--------
22.90 -------- ------------
30.99
36.53
43.04
14.95
17.14 169.02 .373
24.13 169.14 .404
30.94 169.23 .432
36.73 169.31 .454
10.08 168.89 .337
9.53
13.62
16.30
19.56
5.95
S/N:
Bentley PondPack (10.00.027.00)
3:18 PM
Bentley Systems, Inc.
5/14/2010
Type.... Master Network Summary Page 2.02
Name.... Watershed
File.... K:\09\09-0050\090050-Brightwater Ph II\H-H\Pond Pack\Brightwater Biotech Park 05-
MASTER NETWORK SUMMARY
SCS Unit Hydrograph Method
(*Node=Outfall; +Node=Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt)
Max
Return HYG Vol Qpeak Qpeak Max WSEL Pond Storage
Node ID Type Event ac-ft Trun
---- hrs cfs
- ft ac-ft
-----
BMP2 ----- -------
OUT ----
POND ------
2 ------
--
.403 ---------
12.2500 --
-----
4.37 --------
162.76 ------------
.201
BMP2 OUT POND 10 .734 12.1500 10.76 162.91 .227
BMP2 OUT POND 25 .948 12.1500 14.09 162.97 .239
BMP2 OUT POND 100 1.316 12.1500 17.04 163.02 .248
BMP2 OUT POND 1 .293 12.3500 .73 162.63 .178
BMP3 IN POND 2 .965 12.1000 21.04
BMP3 IN POND 10 1.720 12.1000 30.51
BMP3 IN POND 25 2.207 12.1000 36.66
BMP3 IN POND 100 3.046 12.1000 44.19
BMP3 IN POND 1 .717 11.9000 12.98
BMP3 OUT POND 2 .854 12.2000 13.55 167.96 .359
BMP3 OUT POND 10 1.606 12.1500 23.69 168.13 .406
BMP3 OUT POND 25 2.092 12.1500 31.07 168.24 .436
BMP3 OUT POND 100 2.929 12.1500 37.81 168.33 .461
BMP3 OUT POND 1 .608 12.1000 5.62 167.79 .315
BMP4 IN POND 2 1.569 12.1000 33.18
BMP4 IN POND 10 2.612 12.1000 44.33
BMP4 IN POND 25 3.270 12.1000 52.08
BMP4 IN POND 100 4.392 12.1000 61.12
BM24 IN POND 1 1.216 11.9000 21.88
BMP4 OUT POND 2 1.558 12.1500 25.36 160.36 .539
BMP4 OUT POND 10 2.600 12.1500 34.29 160.48 .580
BMP4 OUT POND 25 3.258 12.1500 43.81 160.61 .621
BMP4 OUT POND 100 4.379 12.1500 51.87 160.70 .653
BMP4 OUT POND 1 1.205 12.0500 15.25 160.19 .487
*OUT POST TOTAL JCT 2 17.099 12.1000 323.26
*OUT POST TOTAL JCT 10 32.782 12.1000 557.03
*OUT POST TOTAL JCT 25 43.184 12.1000 699.37
*OUT POST TOTAL JCT 100 61.397 12.1000 877.40
*OUT POST TOTAL JCT 1 12.165 11.9500 181.61
S/N: Bentley Systems, Inc.
Bentley PondPack (10.00.027.00) 3:18 PM 5/14/2010
'Type.... Master Network Summary Page 2.03
Name.... Watershed
File.... K:\09\09-0050\090050-Brightwater Ph II\H-H\Pond Pack\Brightwater Biotech Park 05-
MASTER NETWORK SUMMARY
SCS Unit Hydregraph Method
(*Node=Outfall; +Node=Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt)
Return HYG Vol
Node ID Type Event ac-ft Trun
----------------
*OUT PRE TOTAL - ----
JCT ------
2 ----------
17.022
*OUT PRE TOTAL JCT 10 33.524
*OUT PRE TOTAL JCT 25 44.586
*OUT PRE TOTAL JCT 100 64.023
*OUT PRE TOTAL JCT 1 11.888
TO BMP 1 AREA 2 1.075
TO BMP 1 AREA 10 1.809
TO BMP 1 AREA 25 2.274
TO BMP 1 AREA 100 3.068
TO BMP 1 AREA 1 .827
TO BMP2 AREA 2 .438
TO BMP2 AREA 10 .773
TO BMP2 AREA 25 .987
TO BMP2 AREA 100 1.356
TO BMP2 AREA 1 .328
TO BMP3 AREA 2 .965
TO BMP3 AREA 10 1.720
TO BMP3 AREA 25 2.207
TO BMP3 AREA 100 3.046
TO BMP3 AREA 1 .717
TO BMP4 AREA 2 1.569
TO BMP4 AREA 10 2.612
TO BMP4 AREA 25 3.270
TO BMP4 AREA 100 4.392
TO BMP4 AREA 1 1.216
TO PRE AREA 2 17.022
TO PRE AREA 10 33.524
TO PRE AREA 25 44.586
TO PRE AREA 100 64.023
TO PRE AREA 1 11.888
Max
Qpeak Qpeak Max WSEL Pond Storage
hrs
--------- cfs ft ac-ft

12.3000 -------- -------- ------------
221.77
12.2500 351.17
12.2500 480.01
12.2500 616.36
12.1000 146.95
12.1000 22.90
12.1000 30.99
12.1000 36.53
12.1000 43.04
11.9000 14.95
12.1000 9.53
12.1000 13.62
12.1000 16.30
12.1000 19.56
11.9000 5.95
12.1000 21.04
12.1000 30.51
12.1000 36.66
12.1000 44.19
11.9000 12.98
12.1000 33.18
12.1000 44.33
12.1000 52.08
12.1000 61.12
11.9000 21.88
12.3000 221.77
12.2500 351.17
12.2500 480.01
12.2500 616.36
12.1000 146.95
SIN:
Bentley PondPack (10.00.027.00)
3:18 PM
Bentley Systems, Inc.
5/14/2010
Type.... Master Network Summary Page 2.04
Name.... Watershed
File.... K:\09\09-0050\090050-Brightwater Ph II\H-H\Pond Pack\Brightwater Biotech Park 05-
MASTER NETWORK SUMMARY
SCS Unit Hydrograph Method
(*Node=Outfall; +Node=Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt)
Max
Return HYG Vol Qpeak Qpeak Max WSEL Pond Storage
Node ID Type Event ac-ft Trun hrs cfs ft ac-ft
-
-----------
UNTREATED ------
POST ----
AREA ------
2 ----------
13.214 ---------
12.1000 -------- -----
-- ------------
287.30
UNTREATED POST AREA 10 26.038 12.1000 475.08
UNTREATED POST AREA 25 34.618 12.1000 592.50
UNTREATED POST AREA 100 49.710 12.1000 747.50
UNTREATED POST AREA 1 9.236 11.9500 165.87
SIN:
Bentley PondPack (10.00.027.00)
3:18 PM
Bentley Systems, Inc.
5/14/2010
r
BRIGHTWATER SCIENCE AND TECHNOLOGY PARK
STORMWATER MANAGEMENT REPORT
HARNETT COUNTY, NORTH CAROLINA
MASTER PLAN
BMP SIZING CALCULATIONS
Brightwater Science and Technology Park
Stormwater Management Report
W&R Project 2090050
March 2010

BRIGHTWATER BIOTECH PARK
2090050.00
HARNETT COUNTY, NORTH CAROLINA
MASTER PLAN BMP SIZING REQUIREMENTS

DA
TOTAL
DA (AC) ESTIMATED
IMPERVIOUS
(AC) SURFACE AREA
REQUIRED
(SF) WQV
REQUIRED
(CF)
IMP
%
T1 10.01 5.02 11,509 23414 50.1
T2 7.44 4.01 7,106 14451 53.9
T3 19.83 11.38 19,964 40778 57.4
T4 8.52 4.43 7,897 16019 52.0
01 5.67 3.10 2,823 5783 54.7
02 4.13 2.41 4,257 8552 58.4
03 7.37 3.87 6,887 13981 52.5
R1 6.45 3.79 6,625 13553 58.8
R3 4.08 1.94 3,517 7079 47.5
RW4 2.78 1.09 2,058 4066 39.2
RW5 2.58 0.88 1,686 3343 34.1
HHS 20.09 - - - -

Project Name: Brightwater Biotech Park
City/State: Lillington, NC
Project #: 2090050
Date: 9-J u I-10
Table 10-1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 85% Pollutant Removal
Efficiency in the Moutains and Piedmont
% Impervious Permanent Pool Dept h (feet)
Cover 3.0 4.0 5.0 6.0 7.0 8.0 9.0
10 0.59 0.49 0.43 0.35 0.31 0.29 0.26
20 0.97 0.79 0.70 0.59 0.51 0.46 0.44
30 1.34 1.08 0.97 0.83 0.70 0.64 0.62
40 1.73 1.43 1.25 1.05 0.90 0.82 0.77
50 2.06 1.73 1.50 1.30 1.09 1.00 0.92
60 2.40 2.03 1.71 1.51 1.29 1.18 1.10
70 2.88 2.40 2.07 1.79 1.54 1.35 1.26
80 3.36 2.78 2.38 2.10 1.86 1.60 1.42
90 3.74 3.10 2.66 2.34 2.11 1.83 1.67
Source: NCDENR/DWQ Stormwater Best Management Practices, pg. 10-9, July 2007
STORMWATER BMP T1

Land Use Area
(ac) % IA Imp. Area
(ac)
Impervious 6.5 100 6.5
Open Space 5.5 0 0.0

Totals 12 6.5
Total % Impervious Surface Area = 54.2 %
Surface Area of Permanent Pool:
Assumed depth = 3 feet
SA/DA ratio = 2.20 % From Table 10-1
Minimum pond surface area (SA) _ (DA * SA/DA ratio)/100
SA = y q.64 acres
11509 sq.ft.
Normal pool elevation = 0.0 feet
Surface area provided = 0.000 acres
0 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(1) where, Rv = Runoff coefficient, in./in.
I = Percent impervious
Rv = 0.54 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = 0.53rl.' acre-ft
23414 cu. ft.
Water quality pool elevation = 0.00 feet
Storage volume provided = 0.000 acre-ft
0 cu. ft.
0. ,
Project Name: Brightwater Biotech Park
City/State: Lillington, NC
Project #: 2090050
Date: 9-j u I-10
Table 10-1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 85% Pollutant Removal
Efficiency in the Moutains and Piedmont
% Impervious Permanent Pool Depth (feet)
Cover 3.0 4.0 5.0 6.0 7.0 8.0 9.0
10 0.59 0.49 0.43 0.35 0.31 0.29 0.26
20 0.97 0.79 0.70 0.59 0.51 0.46 0.44
30 1.34 1.08 0.97 0.83 0.70 0.64 0.62
40 1.73 1.43 1.25 1.05 0.90 0.82 0.77
50 2.06 1.73 1.50 1.30 1.09 1.00 0.92
60 2.40 2.03 1.71 1.51 1.29 1.18 1.10
70 2.88 2.40 2.07 1.79 1.54 1.35 1.26
80 3.36 2.78 2.38 2.10 1.86 1.60 1.42
90 3.74 3.10 2.66 2.34 2.11 1.83 1.67
Source: NCUtNK/UWQ Normwater Best Management Practices, pg. 10-9, July 2007
STORMWATER BMP T2

Land Use Area
(ac) % IA Imp. Area
(ac)
Impervious 4.01 100 4.0
Open Space 3.43 0 0.0

Totals 7.44 4.0
Total % Impervious Surface Area = 53.9 %
Surface Area of Permanent Pool:
Assumed depth = 3 feet
SA/DA ratio = 2.19 % From Table 10-1
Minimum pond surface area (SA) = (DA * SA/DA ratio)/100
SA = X00 acres
7106 sq. ft.
Normal pool elevation = 0.0 feet
Surface area provided = 0.000 acres
0 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(1) where, Rv = Runoff coefficient, in./in.
I = Percent impervious
Rv = 0.54 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = 0232 acre-ft
14451 cu. ft.
Water quality pool elevation = 0.00 feet
Storage volume provided = 0.000 acre-ft
0 cu. ft.

Project Name: Brightwater Biotech Park
City/State: Lillington, NC
Project #: 2090050
Date: 9-Ju I-10
Table 10-1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 85% Pollutant Removal
Efficient in the Moutains and Piedmont
% Impervious Permanent Pool Depth (feet)
Cover 3.0 4.0 5.0 6.0 7.0 8.0 9.0
10 0.59 0.49 0.43 0.35 0.31 0.29 0.26
20 0.97 0.79 0.70 0.59 0.51 0.46 0.44
30 1.34 1.08 0.97 0.83 0.70 0.64 0.62
40 1.73 1.43 1.25 1.05 0.90 0.82 0.77
50 2.06 1.73 1.50 1.30 1.09 1.00 0.92
60 2.40 2.03 1.71 1.51 1.29 1.18 1.10
70 2.88 2.40 2.07 1.79 1.54 1.35 1.26
80 3.36 2.78 2.38 2.10 1.86 1.60 1.42
90 3.74 3.10 2.66 2.34 2.11 1.83 1.67
Source: NCDENR/DWQ Stormwater Best Management Practices, pg. 10-9, July 2007
STORMWATER BMP T3

Land Use Area
(ac) % IA Imp. Area
(ac)
Impervious 11.38 100 11.4
Open Space 8.45 0 0.0

Totals 19.83 11.4

Total % Impervious Surface Area = 57.4 %
Surface Area of Permanent Pool:
Assumed depth = 3 feet
SA/DA ratio = 2.31 % From Table 10-1
Minimum pond surface area (SA) = (DA * SA/DA ratio)/100
SA = 9.458 acres
19964 sq.ft.
Normal pool elevation = 0.0 feet
Surface area provided = 0.000 acres
0 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(1) where, Rv = Runoff coefficient, in./in.
I = Percent impervious
Rv = 0.57 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume. S = (Design rainfall) (Rv) (Drainage Area)
S = 0.9:36, acre-ft
40778 cu. ft.
Water quality pool elevation = 0.00 feet
Storage volume provided = 0.000 acre-ft
0 cu. ft.
4 11 Project Name: Brightwater Biotech Park
City/State: Lillington, NC
Project #: 2090050
Date: 9-)ul-10
Table 10-1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 85% Pollutant Removal
Efficient in the Moutains and Piedmont
% Impervious Permanent Pool Depth (feet)
Cover 3.0 4.0 5.0 6.0 7.0 8.0 9.0
10 0.59 0.49 0.43 0.35 0.31 0.29 0.26
20 0.97 0.79 0.70 0.59 0.51 0.46 0.44
30 1.34 1.08 0.97 0.83 0.70 0.64 0.62
40 1.73 1.43 1.25 1.05 0.90 0.82 0.77
50 2.06 1.73 1.50 1.30 1.09 1.00 0.92
60 2.40 2.03 1.71 1.51 1.29 1.18 1.10
70 2.88 2.40 2.07 1.79 1.54 1.35 1.26
80 3.36 2.78 2.38 2.10 1.86 1.60 1.42
90 3.74 3.10 2.66 2.34 2.11 1.83 1.67
Source: NCDENR/DWQ Stormwater Best Management Practices, pg. 10-9, July 2007
STORMWATER BMP T4

Land Use Area
(ac) % IA Imp. Area
(ac)
Impervious 4.43 100 4.4
Open Space 4.09 0 0.0

Totals 8.52 4.4

Total % Impervious Surface Area = 52.0 %
Surface Area of Permanent Pool:
Assumed depth = 3 feet
SA/DA ratio = 2.13 % from Table 10-1
Minimum pond surface area (SA) _ (DA * SA/DA ratio)/100
SA = 010 acres
7897 sq. ft.
Normal pool elevation = 0.0 feet
Surface area provided = 0.000 acres
0 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(p where, Rv = Runoff coefficient, in./in.
I = Percent impervious
Rv = 0.52 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = '' .036 acre-ft
16019 cu. ft.
Water quality pool elevation= 0.00 feet
Storage volume provided = 0.000 acre-ft
0 cu. ft.
r ,
Proiect Name: Brightwater Biotech Park
City/State: Lillington, NC
Project #: 2090050
Date: 9-jut-10
Table 10-1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 85% Pollutant Removal
Efficiency in the Moutains and Piedmont
% Impervious Permanent Pool Depth (feet)
Cover 3.0 4.0 5.0 6.0 7.0 8.0 9.0
10 0.59 0.49 0.43 0.35 0.31 0.29 0.26
20 0.97 0.79 0.70 0.59 0.51 0.46 0.44
30 1.34 1.08 0.97 0.83 0.70 0.64 0.62
40 1.73 1.43 1.25 1.05 0.90 0.82 0.77
50 2.06 1.73 1.50 1.30 1.09 1.00 0.92
60 2.40 2.03 1.71 1.51 1.29 1.18 1.10
70 2.88 2.40 2.07 1.79 1.54 1.35 1.26
80 3.36 2.78 2.38 2.10 1.86 1.60 1.42
90 3.74 3.10 2.66 2.34 2.11 1.83 1.67
Source: NCDENR/DWQ stormwater best management rracaces, pg. w-1), jury zuui
STORMWATER BMP 01

Land Use Area
(ac) % IA Imp. Area
(ac)
Impervious 1.62 100 1.6
Open Space 1.08 0 0.0

Totals 2.7 1.6
Total % Impervious Surface Area = 60.0 %
Surface Area of Permanent Pool:
Assumed depth = 3 feet
SA/DA ratio = 2.40 % From Table 10-1
Minimum pond surface area (SA) = (DA * SA/DA ratio)/100
SA = A.06.5 ' acres
1825 sq. ft.
Normal pool elevation = 0.0 feet
Surface area provided = 0.000 acres
0 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler 0987)
Rv = 0.05 + 0.009() where, Rv = Runoff coefficient, in./in.
I = Percent impervious
Rv - 0.59 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume. S = (Design rainfall) (Rv) (Drainage Area)
S = fl.433 .',acre-ft
5783 . cu. ft.
Water quality pool elevation = 0.00 feet
Storage volume provided = 0.000 acre-ft
0 cu. ft.
I I I
Project Name: Brightwater Biotech Park
City/State: Lillington, NC
Proiect #: 2090050
Date: 9-Jul-10
Table 10-1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 85% Pollutant Removal
Efficiency in the Moutains and Piedmont
1716 Impervious Permanent Pool Dept h (feet)
Cover 3.0 4.0 5.0 6.0 7.0 8.0 9.0
10 0.59 0.49 0.43 0.35 0.31 0.29 0.26
20 0.97 0.79 0.70 0.59 0.51 0.46 0.44
30 1.34 1.08 0.97 0.83 0.70 0.64 0.62
40 1.73 1.43 1.25 1.05 0.90 0.82 0.77
50 2.06 1.73 1.50 1.30 1.09 1.00 0.92
60 2.40 2.03 1.71 1.51 1.29 1.18 1.10
70 2.88 2.40 2.07 1.79 1.54 1.35 1.26
80 3.36 2.78 2.38 2.10 1.86 1.60 1.42
90 3.74 3.10 2.66 2.34 2.11 1.83 1.67
Source: NCDENR/DWQ Stormwater best Management rracuces, pg. iu-9, twy euui
STORMWATER BMP 03

Land Use Area
(ac) % IA Imp. Area
(ac)
Impervious 3.87 100 3.9
Open Space 3.5 0 0.0

Totals 7.37 3.9
Total % Impervious Surface Area = 52.5 °%
Surface Area of Permanent Pool:
Assumed depth = 3 feet
SA/DA ratio = 2.15 % From Table 10-1
Minimum pond surface area (SA) _ (DA * SA/DA ratio)/100
SA .158 acres
6887 sq. ft.
Normal pool elevation = 0.0 feet
Surface area provided = 0.000 acres
0 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler 0 987)
Rv = 0.05 + 0.009() where, Rv = Runoff coefficient, in./in.
I = Percent impervious
Rv - 0.52 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = 0`32 acre-ft
13981 cu. ft.
Water quality pool elevation = 0.00 feet
Storage volume provided = 0.000 acre-ft
0 cu. ft.

Project Name: Brightwater Biotech Park
City/State: Lillington, NC
Project #: 2090050
Date: 9-Jul-10
Table 10-1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 85% Pollutant Removal
Efficient in the Moutains and Piedmont
% Impervious Permanent Pool Dept h (feet)
Cover 3.0 4.0 5.0 6.0 7.0 8.0 9.0
10 0.59 0.49 0.43 0.35 0.31 0.29 0.26
20 0.97 0.79 0.70 0.59 0.51 0.46 0.44
30 1.34 1.08 0.97 0.83 0.70 0.64 0.62
40 1.73 1.43 1.25 1.05 0.90 0.82 0.77
50 2.06 1.73 1.50 1.30 1.09 1.00 0.92
60 2.40 2.03 1.71 1.51 1.29 1.18 1.10
70 2.88 2.40 2.07 1.79 1.54 1.35 1.26
80 3.36 2.78 2.38 2.10 1.86 1.60 1.42
90 3.74 3.10 2.66 2.34 2.11 1.83 1.67
Source: NCDENR/DWQ Stormwater Best Management Practices, pg. 1 U-9, July 2uul
STORMWATER BMP R1

Land Use Area
(ac) % IA Imp. Area
(ac)
Impervious 3.79 100 3.8
Open Space 2.66 0 0.0

Totals 6.45 3.8
Total % Impervious Surface Area = 58.8 %
Surface Area of Permanent Pool:
Assumed depth = 3 feet
SA/DA ratio = 2.36 % From Table 10-1
Minimum pond surface area (SA) = (DA * SA/DA ratio)/100
SA = ;0.152, acres
6625 sq. ft.
Normal pool elevation = 0.0 feet
Surface area provided = 0.000 acres
0 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(1) where, Rv = Runoff coefficient, in./in.
I = Percent impervious
Rv = 0.58 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = " 0.311 ' acre-ft
13553 cu. ft.
Water quality pool elevation = 0.00 feet
Storage volume provided = 0.000 acre-ft
0 cu. ft.

Project Name: Brightwater Biotech Park
City/State: Lillington, NC
Project #: 2090050
Date: 9-)ul-10
Table 10-1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 85% Pollutant Removal
Efficient in the Moutains and Piedmont
7/6 Impervious Permanent Pool Dept h (feet)
Cover 3.0 4.0 5.0 6.0 7.0 8.0 9.0
10 0.59 0.49 0.43 0.35 0.31 0.29 0.26
20 0.97 0.79 0.70 0.59 0.51 0.46 0.44
30 1.34 1.08 0.97 0.83 0.70 0.64 0.62
40 1.73 1.43 1.25 1.05 0.90 0.82 0.77
50 2.06 1.73 1.50 1.30 1.09 1.00 0.92
60 2.40 2.03 1.71 1.51 1.29 1.18 1.10
70 2.88 2.40 2.07 1.79 1.54 1.35 1.26
80 3.36 2.78 2.38 2.10 1.86 1.60 1.42
90 3.74 3.10 2.66 2.34 2.11 1.83 1.67
Source: NCDENR/DWQ btormwater tsest management rracuces, pg. i u-7, luiy zuui
STORMWATER BMP R3

Land Use Area
(ac) % IA Imp. Area
(ac)
Impervious 1.94 100 1.9
Open Space 2.14 0 0.0

Totals 4.08
22? -7 1.9
Total % Impervious Surface Area = 47.5 %
Surface Area of Permanent Pool:
Assumed depth = 3 feet
SA/DA ratio = 1.98 % From Table 10-1
Minimum pond surface area (SA) _ (DA * SA/DA ratio)/100
SA 16.001' acres
3517 sq. ft.
Normal pool elevation = 0.0 feet
Surface area provided = 0.000 acres
0 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009() where, Rv = Runoff coefficient, in./in.
I = Percent impervious
Rv = 0.48 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = 0.163 acre-ft
7079 cu. ft.
Water quality pool elevation= 0.00 feet
Storage volume provided = 0.000 acre-ft
0 cu. ft.
1 0 . . 0
Project Name: Brightwater Biotech Park
City/State: Lillington, NC
Project #: 2090050
Date: 9-Jul-10
Table 10-1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 85% Pollutant Removal
Efficient in the Moutains and Piedmont
% Impervious Permanent Pool Depth (feet)
Cover 3.0 4.0 5.0 6.0 7.0 8.0 9.0
10 0.59 0.49 0.43 0.35 0.31 0.29 0.26
20 0.97 0.79 0.70 0.59 0.51 0.46 0.44
30 1.34 1.08 0.97 0.83 0.70 0.64 0.62
40 1.73 1.43 1.25 1.05 0.90 0.82 0.77
50 2.06 1.73 1.50 1.30 1.09 1.00 0.92
60 2.40 2.03 1.71 1.51 1.29 1.18 1.10
70 2.88 2.40 2.07 1.79 1.54 1.35 1.26
80 3.36 2.78 2.38 2.10 1.86 1.60 1.42
90 3.74 3.10 2.66 2.34 2.11 1.83 1.67
Source: NCDENR/DWQ Stormwater Best Management Practices, pg. 10-9, July 2007
STORMWATER BMP RW4

Land Use Area
(ac) % IA Imp. Area
(ac)
Impervious 1.09 100 1.1
Open Space 1.69 0 0.0

Totals 2.78 1.1
Total % Impervious Surface Area = 39.2 %
Surface Area of Permanent Pool:
Assumed depth = 3 feet
SA/DA ratio = 1.70 % From Table 10-1
Minimum pond surface area (SA) = (DA * SA/DA ratio)/100
SA = 0.047 acres
2u?8 sq. ft.
Normal pool elevation = 0.0 feet
Surface area provided = 0.000 acres
0 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(1) where, Rv = Runoff coefficient, in./in.
I = Percent impervious
Rv = 0.40 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = 0.093 acre-ft
4066 cu.ft.
Water quality pool elevation= 0.00 feet
Storage volume provided = 0.000 acre-ft
0 cu. ft.
0 " 0
Project Name: Brightwater Biotech Park
City/State: Lillington, NC
Project #: 2090050
Date: 9-Ju I-10
Table 10-1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 85% Pollutant Removal
Efficiency in the Moutains and Piedmont
% Impervious Permanent Pool Dept h (feet)
Cover 3.0 4.0 5.0 6.0 7.0 8.0 9.0
10 0.59 0.49 0.43 0.35 0.31 0.29 0.26
20 0.97 0.79 0.70 0.59 0.51 0.46 0.44
30 1.34 1.08 0.97 0.83 0.70 0.64 0.62
40 1.73 1.43 1.25 1.05 0.90 0.82 0.77
50 2.06 1.73 1.50 1.30 1.09 1.00 0.92
60 2.40 2.03 1.71 1.51 1.29 1.18 1.10
70 2.88 2.40 2.07 1.79 1.54 1.35 1.26
80 3.36 2.78 2.38 2.10 1.86 1.60 1.42
90 3.74 3.10 2.66 2.34 2.11 1.83 1.67
Source: NCDENR/DWQ Stormwater Best Management Practices, pg. 10.9, July 2007
STORMWATER BMP RW5

Land Use Area
(ac) % IA Imp. Area
(ac)
Impervious 0.88 100 0.9
Open Space 1.7 0 0.0

Totals 2.58 0.9
Total % Impervious Surface Area = 34.1 %
Surface Area of Permanent Pool:
Assumed depth = 3 feet
SA/DA ratio = 1.50 % From Table 10-1
Minimum pond surface area (SA) _ (DA * SA/DA ratio)/100
SA = 0.09 acres
1686 sq. ft.
Normal pool elevation = 0.0 feet
Surface area provided = 0.000 acres
0 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(1) where, Rv = Runoff coefficient, in./in.
I = Percent impervious
Rv = 0.36 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume. S = (Design rainfall) (Rv) (Drainage Area)
S = O.Oir acre-ft
3343 cu. ft.
Water quality pool elevation = 0.00 feet
Storage volume provided = 0.000 acre-ft
0 cu. ft.
Permit Number:
(to be provided b DWQ)
Drainage Area Number: -V_
Wet Detention Basin Operation and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BMP.
The wet detention basin system is defined as the wet detention basin,
pretreatment including forebays and the vegetated filter if one is provided.
This system (check one):
? does X does not
This system (check one):
? does does not
incorporate a vegetated filter at the outlet.
incorporate pretreatment other than a forebay.
Important maintenance procedures:
- Immediately after the wet detention basin is established, the plants on the
vegetated shelf and perimeter of the basin should be watered twice weekly if
needed, until the plants become established (commonly six weeks).
- No portion of the wet detention pond should be fertilized after the first initial
fertilization that is required to establish the plants on the vegetated shelf.
- Stable groundcover should be maintained in the drainage area to reduce the
sediment load to the wet detention basin.
- If the basin must be drained for an emergency or to perform maintenance, the
flushing of sediment through the emergency drain should be minimized to the
maximum extent practical.
- Once a year, a dam safety expert should inspect the embankment.
After the wet detention pond is established, it should be inspected once a month and
within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a
Coastal County). Records of operation and maintenance should be kept in a known set
location and must be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the problem:
The entire BMP Trash/ debris is resent. Remove the trash/debris.
The perimeter of the wet Areas of bare soil and/or Regrade the soil if necessary to
detention basin erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Vegetation is too short or too Maintain vegetation at a height of
long. approximate) six inches.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 1 of 4
Permit Number:
(to be provided by DWQ)
Drainage Area Number: /A P 1
BMP element: Potential problem: How I will remediate the problem:
The inlet device: pipe or The pipe is clogged. Unclog the pipe. Dispose of the
swale sediment off-site.
The pipe is cracked or Replace the pipe.
otherwise damaged.
Erosion is occurring in the Regrade the swale if necessary to
swale. smooth it over and provide erosion
control devices such as reinforced
turf matting or riprap to avoid
future problems with erosion.
The forebay Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design depth for possible. Remove the sediment and
sediment storage. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Erosion has occurred. Provide additional erosion
protection such as reinforced turf
matting or riprap if needed to
prevent future erosion problems.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The vegetated shelf Best professional practices Prune according to best professional
show that pruning is needed practices
to maintain optimal plant
health.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application to establish the
ground cover if a soil test indicates
it is necessary.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The main treatment area Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design sediment possible. Remove the sediment and
storage depth. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Algal growth covers over Consult a professional to remove
50% of the area. and control the algal growth.
Cattails, phragmites or other Remove the plants by wiping them
invasive plants cover 50% of with pesticide (do not spray).
the basin surface.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 2 of 4
Permit Number:
(to be provided by DWQ)
Drainage Area Number: R P I
BMP element: Potential problem: How I will remediate the problem:
The embankment Shrubs have started to grow Remove shrubs immediately.
on the embankment.
Evidence of muskrat or Use traps to remove muskrats and
beaver activity is present. consult a professional to remove
beavers.
A tree has started to grow on Consult a dam safety specialist to
the embankment. remove the tree.
An annual inspection by an Make all needed repairs.
appropriate professional
shows that the embankment
needs repair. (if applicable)
The outlet device Clogging has occurred. Clean out the outlet device. Dispose
of the sediment off-site.
The outlet device is damaged Repair or replace the outlet device.
The receiving water Erosion or other signs of Contact the local NC Division of
damage have occurred at the Water Quality Regional Office, or
outlet. the 401 Oversight Unit at 919-733-
1786.
The measuring device used to determine the sediment elevation shall be such
that it will give an accurate depth reading and not readily penetrate into
accumulated sediments.
When the permanent pool depth reads_ feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads feet in the forebay, the sediment
shall be removed.
Sediment Removal
Bottom
BASIN DIAGRAM
ill in the blanks)
0 Permanent Pool Elevation . 5 v
.?j Pe anen Pool , ?,?• ?-v
- - - - - - - - - - - - - - Volume Sediment Removal Elevation
?S -ft Min. ----------------------------------------- -?
162.So
Sediment Bottom Elevation
Storage
FOREBAY MAIN POND
Volume
------I
1-ft
Storage
Form SW401-Wet Detention Bain O&M-Rev.4 Page 3 of 4
Permit Number:
(to be provided by DWQ)
I acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the system or prior to any changes to the system or responsible party.
Project name: 1, r
tw0.?t?- Sc;Qh GQ ?-?2chino?o qy Pac
BMP drainage area number:
Print name:
Title:
Address:
Phone:
Signature:
Date:
Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
I,
a Notary Public for the State of
, County of , do hereby certify that
personally appeared before me this
day of , and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal,
SEAL
My commission expires
Form SW401-Wet Detention Basin O&M-Rev.4 Page 4 of 4
Permit Number:
(to be provided b DWQ)
Drainage Area Number: /U\
Wet Detention Basin Operation and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BMP.
The wet detention basin system is defined as the wet detention basin,
pretreatment including forebays and the vegetated filter if one is provided.
This system (check one):
? does [does not
This system (check one):
? does N does not
incorporate a vegetated filter at the outlet.
incorporate pretreatment other than a forebay.
Important maintenance procedures:
- Immediately after the wet detention basin is established, the plants on the
vegetated shelf and perimeter of the basin should be watered twice weekly if
needed, until the plants become established (commonly six weeks).
- No portion of the wet detention pond should be fertilized after the first initial
fertilization that is required to establish the plants on the vegetated shelf.
- Stable groundcover should be maintained in the drainage area to reduce the
sediment load to the wet detention basin.
- If the basin must be drained for an emergency or to perform maintenance, the
flushing of sediment through the emergency drain should be minimized to the
maximum extent practical.
- Once a year, a dam safety expert should inspect the embankment.
After the wet detention pond is established, it should be inspected once a month and
within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a
Coastal County). Records of operation and maintenance should be kept in a known set
location and must be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will rentediate the problem:
The entire BMP Trash/ debris is resent. Remove the trash/ debris.
The perimeter of the wet Areas of bare soil and/or Regrade the soil if necessary to
detention basin erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Vegetation is too short or too Maintain vegetation at a height of
long. approximately six inches.
Forn1 SW401-Wet Detention Basin O&M-Rev.4 Page 1 of 4
Permit Number:
(to be provided by DWQ)
Drainage Area Number: V_'A P 2
BMP element: Potential problem: How I will remediate the problem:
The inlet device: pipe or The pipe is clogged. Unclog the pipe. Dispose of the
swale sediment off-site.
The pipe is cracked or Replace the pipe.
otherwise damaged.
Erosion is occurring in the Regrade the swale if necessary to
swale. smooth it over and provide erosion
control devices such as reinforced
turf matting or riprap to avoid
future problems with erosion.
The forebay Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design depth for possible. Remove the sediment and
sediment storage. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Erosion has occurred. Provide additional erosion
protection such as reinforced turf
matting or riprap if needed to
prevent future erosion problems.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The vegetated shelf Best professional practices Prune according to best professional
show that pruning is needed practices
to maintain optimal plant
health.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application to establish the
ground cover if a soil test indicates
it is necessary.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The main treatment area Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design sediment possible. Remove the sediment and
storage depth. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Algal growth covers over Consult a professional to remove
50% of the area. and control the algal growth.
Cattails, phragmites or other Remove the plants by wiping them
invasive plants cover 50% of with pesticide (do not spray).
the basin surface.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 2 of 4

Permit Number:
(to be provided by DWQ)
Drainage Area Number: 19 Ae 2.
BMP element: Potential problem: How I will remediate the problem:
The embankment Shrubs have started to grow Remove shrubs immediately.
on the embankment.
Evidence of muskrat or Use traps to remove muskrats and
beaver activity is present. consult a professional to remove
beavers.
A tree has started to grow on Consult a dam safety specialist to
the embankment. remove the tree.
An annual inspection by an Make all needed repairs.
appropriate professional
shows that the embankment
needs repair. (if applicable)
The outlet device Clogging has occurred. Clean out the outlet device. Dispose
of the sediment off-site.
The outlet device is damaged Repair or replace the outlet device.
The receiving water Erosion or other signs of Contact the local NC Division of
damage have occurred at the Water Quality Regional Office, or
outlet. the 401 Oversight Unit at 919-733-
1786.
The measuring device used to determine the sediment elevation shall be such
that it will give an accurate depth reading and not readily penetrate into
accumulated sediments.
When the permanent pool depth reads feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads IS feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
(fill in the blanks)
Permanent Pool Elevation' •V?
Sediment Removal
?sg l
-----------------
? 1577 t
efrnanen Pool
/Volume Sediment Removal Elevation ?, - Volume
-ft Min. ----------------
Sediment Bottom Elevation ?? 1-ft r.
Storage Sedimei
Bottom
FOREBAY
Form SW401-Wet Detention Basin O&M-Rev.4
MAIN POND
Page 3 of 4
Storage
Permit Number:
(to be provided by DWQ)
I acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the system or prior to any changes to the system or responsible party.
Project name: R., f 1,? "?t'r S C',-2hGQ'aC? T`2C?V\0 I o,?,y P?f r?
BMP drainage area number: 3A f -
2-Print name:
Title:
Address:
Phone:
Signature:-
Date:
Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
I,
day of
a Notary Public for the State of
County of , do hereby certify that
personally appeared before me this _
and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal,
SEAL
My commission expires
Form SW401-Wet Detention Basin O&M-Rev.4 Page 4 Of 4
Permit Number:
(to be provided b DWQ)
Drainage Area Number: ??_?-
Wet Detention Basin Operation and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BMP.
The wet detention basin system is defined as the wet detention basin,
pretreatment including forebays and the vegetated filter if one is provided.
This system (check one):
? does X does not
This syst (check one):
? does does not
incorporate a vegetated filter at the outlet.
incorporate pretreatment other than a forebay.
Important maintenance procedures:
- Immediately after the wet detention basin is established, the plants on the
vegetated shelf and perimeter of the basin should be watered twice weekly if
needed, until the plants become established (commonly six weeks).
- No portion of the wet detention pond should be fertilized after the first initial
fertilization that is required to establish the plants on the vegetated shelf.
- Stable groundcover should be maintained in the drainage area to reduce the
sediment load to the wet detention basin.
- If the basin must be drained for an emergency or to perform maintenance, the
flushing of sediment through the emergency drain should be minimized to the
maximum extent practical.
- Once a year, a dam safety expert should inspect the embankment.
After the wet detention pond is established, it should be inspected once a month and
within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a
Coastal County). Records of operation and maintenance should be kept in a known set
location and must be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the problem:
The entire BMP Trash/ debris is resent. Remove the trash/ debris.
The perimeter of the wet Areas of bare soil and/or Regrade the soil if necessary to
detention basin erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Vegetation is too short or too Maintain vegetation at a height of
101 18. approximately six inches.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 1 of 4
Permit Number:
(to be provided by DWQ)
Drainage Area Number: 5 P 3
BMP element: Potential problem: How I will remediate the problem:
The inlet device: pipe or The pipe is clogged. Unclog the pipe. Dispose of the
swale sediment off-site.
The pipe is cracked or Replace the pipe.
otherwise damaged.
Erosion is occurring in the Regrade the swale if necessary to
swale. smooth it over and provide erosion
control devices such as reinforced
turf matting or riprap to avoid
future problems with erosion.
The forebay Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design depth for possible. Remove the sediment and
sediment storage. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Erosion has occurred. Provide additional erosion
protection such as reinforced turf
matting or riprap if needed to
prevent future erosion problems.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The vegetated shelf Best professional practices Prune according to best professional
show that pruning is needed practices
to maintain optimal plant
health.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application to establish the
ground cover if a soil test indicates
it is necessary.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The main treatment area Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design sediment possible. Remove the sediment and
storage depth. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Algal growth covers over Consult a professional to remove
50% of the area. and control the algal growth.
Cattails, phragmites or other Remove the plants by wiping them
invasive plants cover 50% of with pesticide (do not spray).
the basin surface.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 2 of 4
Permit Number:
(to be provided b DWQ)
Drainage Area Number: /A
BMP element: Potential problem: How I will remediate the problem:
The embankment Shrubs have started to grow Remove shrubs immediately.
on the embankment.
Evidence of muskrat or Use traps to remove muskrats and
beaver activity is present. consult a professional to remove
beavers.
A tree has started to grow on Consult a dam safety specialist to
the embankment. remove the tree.
An annual inspection by an Make all needed repairs.
appropriate professional
shows that the embankment
needs repair. (if applicable)
The outlet device Clogging has occurred. Clean out the outlet device. Dispose
of the sediment off-site.
The outlet device is damaged Repair or replace the outlet device.
The receiving water Erosion or other signs of Contact the local NC Division of
damage have occurred at the Water Quality Regional Office, or
outlet. the 401 Oversight Unit at 919-733-
1786.
The measuring device used to determine the sediment elevation shall be such
that it will give an accurate depth reading and not readily penetrate into
accumulated sediments.
When the permanent pool depth reads ?t feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads 3'S feet in the forebay, the sediment
shall be removed.
Sediment Removal
Bottom
BASIN DIAGRAM
(fill in the blanks)
0 Permanent Pool Elevation
Pe anen Pool
L - - - - - - - - - - Volume Sediment Removal Elevation 12 Volume
-ft Min. -----------------------------? -----------
Sediment Bottom Elevation 1-ft n
Storage Sedimei
Storage
FOREBAY MAIN POND
Form SW401-Wet Detention Basin O&M-Rev.4 Page 3 of 4
Permit Number:
(to be provided by DWQ)
I acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the syst1emL or prior to any changes to the system or responsible party.
Project name: ?? t ??` oA-? f c%k),1tA_4 T2cann? o ?t ??'
BMP drainage area number: I?A`p
Print name:
Title:
Address:
Phone:
Signature:-
Date:
Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
I,
a Notary Public for the State of
County of , do hereby certify that
personally appeared before me this _
day of , and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal,
SEAL
My commission expires
Forth SW401-Wet Detention Basel O&M-Rev.4 Page 4 of 4
Permit Number:
(to be provided b DWQ)
Drainage Area Number: /A ? L4
Wet Detention Basin Operation and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BMP.
The wet detention basin system is defined as the wet detention basin,
pretreatment including forebays and the vegetated filter if one is provided.
This system check one):
? does C9 does not
This system check one):
? does 7 does not
incorporate a vegetated filter at the outlet.
incorporate pretreatment other than a forebay.
Important maintenance procedures:
- Immediately after the wet detention basin is established, the plants on the
vegetated shelf and perimeter of the basin should be watered twice weekly if
needed, until the plants become established (commonly six weeks).
- No portion of the wet detention pond should be fertilized after the first initial
fertilization that is required to establish the plants on the vegetated shelf.
- Stable groundcover should be maintained in the drainage area to reduce the
sediment load to the wet detention basin.
- If the basin must be drained for an emergency or to perform maintenance, the
flushing of sediment through the emergency drain should be minimized to the
maximum extent practical.
- Once a year, a dam safety expert should inspect the embankment.
After the wet detention pond is established, it should be inspected once a month and
within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a
Coastal County). Records of operation and maintenance should be kept in a known set
location and must be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the problem:
The entire BMP Trash/ debris is resent. Remove the trash/ debris.
The perimeter of the wet Areas of bare soil and/or Regrade the soil if necessary to
detention basin erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Vegetation is too short or too Maintain vegetation at a height of
long. approximately six inches.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 1 of 4
Permit Number:
(to be provided by DWQ)
Drainage Area Number: L
BMP element: Potential problem: How I will remediate the problem:
The inlet device: pipe or The pipe is clogged. Unclog the pipe. Dispose of the
swale sediment off-site.
The pipe is cracked or Replace the pipe.
otherwise damaged.
Erosion is occurring in the Regrade the swale if necessary to
swale. smooth it over and provide erosion
control devices such as reinforced
turf matting or riprap to avoid
future problems with erosion.
The forebay Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design depth for possible. Remove the sediment and
sediment storage. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Erosion has occurred. Provide additional erosion
protection such as reinforced turf
matting or riprap if needed to
prevent future erosion problems.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The vegetated shelf Best professional practices Prune according to best professional
show that pruning is needed practices
to maintain optimal plant
health.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application to establish the
ground cover if a soil test indicates
it is necessary.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The main treatment area Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design sediment possible. Remove the sediment and
storage depth. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Algal growth covers over Consult a professional to remove
50% of the area. and control the algal growth.
Cattails, phragmites or other Remove the plants by wiping them
invasive plants cover 50% of with pesticide (do not spray).
the basin surface.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 2 of 4

Permit Number:
(to be prov'ded by DWQ)
Drainage Area Number:
BMP element: Potential problem: How I will remediate the problem:
The embankment Shrubs have started to grow Remove shrubs immediately.
on the embankment.
Evidence of muskrat or Use traps to remove muskrats and
beaver activity is present. consult a professional to remove
beavers.
A tree has started to grow on Consult a dam safety specialist to
the embankment. remove the tree.
An annual inspection by an Make all needed repairs.
appropriate professional
shows that the embankment
needs repair. (if applicable)
The outlet device Clogging has occurred. Clean out the outlet device. Dispose
of the sediment off-site.
The outlet device is damaged Repair or replace the outlet device.
The receiving water Erosion or other signs of Contact the local NC Division of
damage have occurred at the Water Quality Regional Office, or
outlet. the 401 Oversight Unit at 919-733-
1786.
The measuring device used to determine the sediment elevation shall be such
that it will give an accurate depth reading and not readily penetrate into
accumulated sediments.
When the permanent pool depth reads - I feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads 3 • 's feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
(fill in the blanks)
Permanent Pool Elevation I ST. S
Sediment Removal
7 ? 11
,may------I
e}hnanen Pool ?.-
- Volume Sediment Removal Elevation Volume
-ft Min. ----
----------------------------------------
Sediment Bottom Elevation 53.E 1-ft r.
Storage Sedimei
Bottom
FOREBAY
Form SW401-Wet Detention Basin O&M-Rev.4
MAIN POND
Page 3 of 4
Storage

Permit Number:
(to be provided by DWQ)
I acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the system or prior to any changes to the system or responsible party.
Project name:
BMP drainage area number:
Print name:
Title:
Address:
Phone:
Signature:_
Date:
Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
I,
a Notary Public for the State of
, County of , do hereby certify that
day of
personally appeared before me this _
and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal,
SEAL
My commission expires
Form SW401-Wet Detention Basin O&M-Rev.4
Page 4 of 4