SW5200501_2020-07-21 Coolwick Stormwater Report_20200722

Stormwater Impact Analysis for
Coolwick Warehouse
80 Weathers Street
Youngsville, North Carolina
May 4, 2020
Revised: July 15, 2020
Prepared for:
Coolwick, LLC
186 Wind Chime Court # 200
Raleigh, North Carolina 27615
PRINT NAME: Josh Crumpler, P.E.
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034994
REGISTRATION NO. PE-034994
111,
CRUMPLER
Consulting Services, PLLC
Prepared by Crumpler Consulting Services, PLLC
2308 Ridge Road, Raleigh, North Carolina 27612
p 1 919.413-1704

CRUMPLER
Consulting Services, PLLC
TABLE OF CONTENTS
1.0 STORMWATER NARRATIVE...............................................................................................2
2.0 DESIGN DATA AND METHODOLOGY................................................................................3
3.0 PRE -DEVELOPMENT STORMWATER RUN-OFF...............................................................4
4.0 POST -DEVELOPMENT STORMWATER RUN-OFF.............................................................5
List of Aapendices
Appendix A — IDF Rainfall Data
Appendix B — Pre -Development Peak Flow Tables (2-yr, 10-yr, and 100-yr)
Appendix C — Post -Development Peak Flow Tables (2-yr, 10-yr, and 100-yr)
Appendix D — Snap Tool Calculations and EZ Supplement Forms
Appendix E — Wetlands and Stream Map
Appendix F — Drainage Area Maps
2308 Ridge Road I Raleigh, NC 27612 1 p: 919-413-1704 1 e: [e-mail]

1.0
STORMWATER NARRATIVE
Coolwick, LLC is proposing to construct two warehouses and three storage units on a parcel
totaling 4.80 acres located at 80 Weathers Street, Youngsville, North Carolina that zoned
Industrial (IND). This report represents the stormwater management design and hydrologic model
results for the proposed project.
As part of the stormwater design, Crumpler Consulting is proposing the installation of a wet
detention basin. The wet detention basin has been designed to control and treat the estimated
runoff generated from the first inch of rainfall per the requirements of the Neuse Watershed
Nutrient Management Strategy and the NCDEQ's stormwater management design manual. The
dry detention facility is anticipated to attenuate the peak flow rates for the 2-year, 10-year, and
100-year 24-hour storm events in accordance with NCDEQ's requirements. The nitrogen loading
rates have been evaluated as part of this design and are anticipated to be reduced to acceptable
rates through treatment by the detention facility and buy down methods.
The existing parcel did have minimal existing impervious surfaces that included an existing
driveway which totaled 16,860sf (0.38 acres). The proposed impervious surface consists of the
warehouse building, parking lot, driveways, and sidewalks. The proposed impervious area will
total 64,677sf (1.48 acres). The proposed grading conveys the majority of the runoff to the
southwest corner of the site, where the runoff is collected in a swale which empties into the dry
detention basin that discharges to the south west side of the site. The Post -Development
Drainage Map shows the stormwater grading and drainage plan and associated details.
Page 2 July 21, 2020

2.0
DESIGN DATA AND METHODOLOGY
The design of the proposed stormwater facilities was performed in accordance with Chapter 12
of the NCDEQ Stormwater BMP Manual.
Hydraflow Hydrographs, a computer modeling software package, was used for the analysis of
stormwater routing and hydrology of the existing and proposed watersheds. The hydrology
calculations were performed using the Modified Ration Method and TR-55 methods. Franklin
County lies within the Type II rainfall distribution. The rainfall amounts for the site were obtained
from National Oceanic and Atmospheric Administration (NOAA) and are included in Appendix A.
The stormwater analyses performed for this project include the 2-year, 10-year, and 100-year,
24-hour storm events.
The Soil Survey of Franklin County, North Carolina, completed by the National Resource
Conservation Service (NRCS), was reviewed for general information on the soils within the site
area.
Page 3 July 21, 2020

3.0
PRE -DEVELOPMENT STORMWATER RUNOFF
The pre -development drainage areas were determined using site visits, visual observations, and
surveyed topographic data. The peak flow rates for the specified storm events are based on
topography, land use cover (such as open space, grass, woods), and soil type. Two drainage
points were selected for analysis.
The existing 3.42-acre watershed was modeled in HydraFlow as one subcatchment, as described
below. Refer to Appendix F of this report for the pre -development watershed map.
• Subcatchment 1
Subcatchment 1 is 3.42 acres and drains to the southwest corner of the property. A time of
concentration was calculated and was found to be approximately 5 minutes. Therefore, 5 minutes
was estimated as the time of concentration for this subcatchment.
The HydroFlow analysis can be found in Appendices. The table below summarizes the hydrologic
model results for pre -development peak flow rates of the existing 3.42-acre watershed.
PRE -DEVELOPMENT STORMWATER RUNOFF
STORM EVENT
PRE -DEVELOPMENT PEAK FLOW
2-YEAR
6.049 CFS
10-YEAR
7.835 CFS
100-YEAR
10.750 CFS
Page 4 July 21, 2020

4.0
POST -DEVELOPMENT STORMWATER RUNOFF
An analysis of the post -development runoff was performed using the same methods, parameters,
and assumptions as described in the pre -development analysis above. Based upon the
calculations, the project reduces the nitrogen loading to acceptable levels for buy -down and does
not create an increase in the peak runoff rate for the 2-year, 1 0-year, and 100-year storm events.
This will be achieved by constructing appropriate BMPs.
The proposed site was divided into two subcatchments for post -development analysis. The
subcatchments are described below. Refer to Appendix F of this report for the post -development
watershed map.
• Drainage Area 1
Drainage Area 1 is 2.13 acres and includes runoff is treated by the dry detention facility.
Runoff that is treated by the dry detention facility is collected in swale and discharged
overland in the southwestern corner of the site. A time of concentration was calculated
and was found to be lower than 5 minutes. Therefore, 5 minutes was estimated as the
time of concentration for this subcatchment.
• Drainage Area 2 (Bypass)
Drainage Area 2 is 1.29 acres and drains offsite to the south bypassing the dry detention
facility. A time of concentration was calculated and was found to be lower than 5 minutes.
Therefore, 5 minutes was estimated as the time of concentration for this subcatchment.
The HydraFlow analysis can be found in Appendices. The follow table summarizes the hydrologic
model results for post -development peak flow rates of the 1.91-acre watershed.
POST -DEVELOPMENT STORMWATER RUNOFF
TOTAL
TOTAL
STORM EVENT
POST -DEVELOPMENT
POST -DEVELOPMENT
PEAK FLOW
PEAK FLOW
WITH OUT SCM
WITH SCM
2-YEAR
9.71 CFS
2.497 CFS
10-YEAR
12.58 CFS
3.273 CFS
100-YEAR
17.25 CFS
9.019 CFS
Page 5 July 21, 2020

APPENDIX A
OF Rainfall Data
Page 6 July 21, 2020

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PDS-based depth -duration -frequency (DDF) curves
Latitude: 315.0299 Longitude:-78-49841
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1 2 5 10 25 50 100 200 500 1000
Average recurrence interval (years)
NDAA Atlas 14, Volume 2, Version 3 Created (GMT): Wed Apr 29 10:51:00 2020
Average recurrence
interval
(years)
— 1
2
— 5
— 1Q
25
50
100
200
500
1000
Duration
— "in —
2-day
— 76-min —
3-day
15-min —
4-day
— 30�-min —
7-day
— 60-min —
10�-eay
— 2-nr —
20-clay
— 3-hr —
30-clay
— 6-hr —
45-day
— 12-hr —
60-day
— 24-hr

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PDS-based intensity -duration -frequency (IDF) curves
Latitude: 315.0289 Longitude:-78.49841
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1 2 5 10 25 50 100 200 500 1000
Average recurrence interval (years)
NDAA Atlas 14, Volume 2, Version 3 Created (GMT): Wed Apr 29 10:52:43 2020
Average recurrence
interval
(years)
—1
2
— 1Q
25
50
100
200
500
1000
Duration
— "in —
2-day
— 76-min —
3-day
I5-min —
4-day
— 30�-min —
7-day
— 60-min —
10-eay
— 2-nr —
20-day
— 3-hr —
34-day
— 6-hr —
45-day
— 12-hr —
6o-eay
— 24-hr

APPENDIX B
Pre -Development Peak Flow Tables (2-yr, 10-yr, and 100-yr)
Page 7 July 21, 2020

Watershed Model Schematic Hydraf low Hydrographs Extension for AutoCAD® Civil 3D® 2018 by Autodesk, Inc. v12
Project: Coolwick-Existing.gpw
Thursday, 04 / 30 / 2020

Hydrograph Summary Report Hydraf low Hydrographs Extension for AutoCAD® Civil 3D® 2018 by Autodesk, Inc. v12
Hyd.
No.
Hydrograph
type
(origin)
Peak
flow
(cfs)
Time
interval
(min)
Time to
Peak
(min)
Hyd.
volume
(cuft)
Inflow
hyd(s)
Maximum
elevation
(ft)
Total
strge used
(cuft)
Hydrograph
Description
1
Mod. Rational
6.049
1
5
3,629
------
------
------
EXISTING CONDITIONS
Coolwick-Existing.gpw
Return Period: 2 Year
Thursday, 04 / 30 / 2020

3
Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2018 by Autodesk, Inc. v12
Hyd. No. 1
EXISTING CONDITIONS
Hydrograph type
= Mod. Rational
Storm frequency
= 2 yrs
Time interval
= 1 min
Drainage area
= 3.420 ac
Intensity
= 4.655 in/hr
IDF Curve
= Revised-Raleigh.IDF
Target Q
=n/a
*Composite (Area/C) _ [(0.150 x 0.95) + (3.270 x 0.35)] / 3.420
Thursday, 04 / 30 / 2020
Peak discharge
= 6.049 cfs
Time to peak
= 5 min
Hyd. volume
= 3,629 cuft
Runoff coeff.
= 0.38*
Tc by User
= 5.00 min
Storm duration
= 2.0 x Tc
Est. Req'd Storage
=n/a
EXISTING CONDITIONS
Q (cfs) Hyd. No. 1 -- 2 Year Q (cfs)
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0 00
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0 00
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Hyd No. 1 Time (min)

4
Hydrograph Summary Report Hydraf low Hydrographs Extension for AutoCAD® Civil 3D® 2018 by Autodesk, Inc. v12
Hyd.
No.
Hydrograph
type
(origin)
Peak
flow
(cfs)
Time
interval
(min)
Time to
Peak
(min)
Hyd.
volume
(cuft)
Inflow
hyd(s)
Maximum
elevation
(ft)
Total
strge used
(cuft)
Hydrograph
Description
1
Mod. Rational
7.835
1
5
4,701
------
------
------
EXISTING CONDITIONS
Coolwick-Existing.gpw
Return Period: 10 Year
Thursday, 04 / 30 / 2020

Hydrograph Report
5
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2018 by Autodesk, Inc. v12
Hyd. No. 1
EXISTING CONDITIONS
Hydrograph type
= Mod. Rational
Storm frequency
= 10 yrs
Time interval
= 1 min
Drainage area
= 3.420 ac
Intensity
= 6.029 in/hr
IDF Curve
= Revised-Raleigh.IDF
Target Q
=n/a
Composite (Area/C) _ [(0.150 x 0.95) + (3.270 x 0.35)] / 3.420
Q (cfs)
8.00
4.00
2.00
0.00 v
0 1 2
Hyd No. 1
Thursday, 04 / 30 / 2020
Peak discharge
= 7.835 cfs
Time to peak
= 5 min
Hyd. volume
= 4,701 cuft
Runoff coeff.
= 0.38*
Tc by User
= 5.00 min
Storm duration
= 2.0 x Tc
Est. Req'd Storage
=n/a
EXISTING CONDITIONS
Hyd. No. 1 -- 10 Year
3 4 5 6 7 8 9
Q (cfs)
8.00
4.00
2.00
A 0.00
10 11 12 13 14 15
Time (min)

Hydrograph Summary Report Hydraf low Hydrographs Extension for AutoCAD® Civil 3D® 2018 by Autodesk, Inc. v12
Hyd.
No.
Hydrograph
type
(origin)
Peak
flow
(cfs)
Time
interval
(min)
Time to
Peak
(min)
Hyd.
volume
(cuft)
Inflow
hyd(s)
Maximum
elevation
(ft)
Total
strge used
(cuft)
Hydrograph
Description
1
Mod. Rational
10.75
1
5
6,449
------
------
------
EXISTING CONDITIONS
Coolwick-Existing.gpw
Return Period: 100 Year
Thursday, 04 / 30 / 2020

Hydrograph Report
I
N
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2018 by Autodesk, Inc. v12
Hyd. No. 1
EXISTING CONDITIONS
Hydrograph type
= Mod. Rational
Storm frequency
= 100 yrs
Time interval
= 1 min
Drainage area
= 3.420 ac
Intensity
= 8.270 in/hr
IDF Curve
= Revised-Raleigh.IDF
Target Q
=n/a
*Composite (Area/C) _ [(0.150 x 0.95) + (3.270 x 0.35)] / 3.420
Q (cfs)
12.00
10.00
4.00
2.00
Thursday, 04 / 30 / 2020
Peak discharge
= 10.75 cfs
Time to peak
= 5 min
Hyd. volume
= 6,449 cuft
Runoff coeff.
= 0.38*
Tc by User
= 5.00 min
Storm duration
= 2.0 x Tc
Est. Req'd Storage
=n/a
EXISTING CONDITIONS
Hyd. No. 1 -- 100 Year
Q (cfs)
12.00
10.00
4.00
2.00
0.00 y ' ' ' ' ' ' ' ' ' ' ' ' ' ' X 0.00
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Hyd No. 1 Time (min)

Hydraflow Rainfall Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2018 by Autodesk, Inc. v12
Return
Period
Intensity -Duration -Frequency Equation Coefficients (FHA)
(Yrs)
B
D
E
(N/A)
1
0.0000
0.0000
0.0000
--------
2
74.0559
13.3000
0.8788
--------
3
0.0000
0.0000
0.0000
--------
5
83.5115
14.8000
0.8514
--------
10
105.7041
16.8000
0.8710
--------
25
118.9249
17.6000
0.8582
--------
50
137.0265
18.6000
0.8630
--------
100
157.1766
19.6000
0.8692
--------
File name: Revised-Raleigh.IDF
Intensity = B / (Tc + D)^E
Thursday, 04 / 30 / 2020
Return Intensity Values (in/hr)
Period
(Yrs)
5 min
10
15
20
25
30
35
40
45
50
55
60
1
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
2
5.76
4.65
3.92
3.40
3.01
2.70
2.45
2.25
2.08
1.93
1.81
1.70
3
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
5
6.57
5.43
4.64
4.07
3.63
3.28
3.00
2.76
2.57
2.40
2.25
2.12
10
7.22
6.03
5.19
4.57
4.09
3.71
3.40
3.13
2.91
2.72
2.56
2.41
25
8.19
6.90
5.98
5.29
4.75
4.32
3.97
3.67
3.41
3.20
3.01
2.84
50
8.95
7.59
6.60
5.86
5.27
4.80
4.41
4.08
3.81
3.57
3.36
3.17
100
9.71
8.27
7.22
6.42
5.79
5.28
4.86
4.50
4.20
3.93
3.70
3.50
Tc = time in minutes. Values may exceed 60.
Storm
rreci . The name: aam ie. c
Rainfall Precipitation Table (in)
Distribution
1-yr
2-yr
3-yr
5-yr
10-yr
25-yr
50-yr
100-yr
SCS 24-hour
0.00
2.20
0.00
3.30
4.25
5.77
6.80
7.95
SCS 6-Hr
0.00
1.80
0.00
0.00
2.60
0.00
0.00
4.00
Huff -1st
0.00
1.55
0.00
2.75
4.00
5.38
6.50
8.00
Huff-2nd
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Huff-3rd
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Huff-4th
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Huff-Indy
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Custom
0.00
1.75
0.00
2.80
3.90
5.25
6.00
7.10

APPENDIX C
Post -Development Peak Flow Tables (2-yr, 10-yr, and 100-yr)
Page 8 July 21, 2020

Watershed Model Schematic Hydraf low Hydrographs Extension for AutoCAD® Civil 3D® 2018 by Autodesk, Inc. v12
Project: Coolwick-Proposed Without BMPs.gpw
Thursday, 04 / 30 / 2020

Hydrograph Summary Report Hydraf low Hydrographs Extension for AutoCAD® Civil 3D® 2018 by Autodesk, Inc. v12
Hyd.
No.
Hydrograph
type
(origin)
Peak
flow
(cfs)
Time
interval
(min)
Time to
Peak
(min)
Hyd.
volume
(cuft)
Inflow
hyd(s)
Maximum
elevation
(ft)
Total
strge used
(cuft)
Hydrograph
Description
1
Mod. Rational
9.710
1
5
5,826
------
------
------
PROPOSED WITHOUT BMP
Coolwick-Proposed Without BMPs.gpw
Return Period: 2 Year
Thursday, 04 / 30 / 2020

Hydrograph Report
3
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2018 by Autodesk, Inc. v12
Hyd. No. 1
PROPOSED WITHOUT BMP
Hydrograph type
= Mod. Rational
Storm frequency
= 2 yrs
Time interval
= 1 min
Drainage area
= 3.420 ac
Intensity
= 4.655 in/hr
IDF Curve
= Revised-Raleigh.IDF
Target Q
=n/a
* Composite (Area/C) _ [(1.480 x 0.95) + (1.940 x 0.35)] / 3.420
Q (cfs)
10.00
. 11
4.00
2.00
Thursday, 04 / 30 / 2020
Peak discharge
= 9.710 cfs
Time to peak
= 5 min
Hyd. volume
= 5,826 cuft
Runoff coeff.
= 0.61 *
Tc by User
= 5.00 min
Storm duration
= 2.0 x Tc
Est. Req'd Storage
=n/a
PROPOSED WITHOUT BMP
Hyd. No. 1 -- 2 Year
Q (cfs)
10.00
. 11
4.00
2.00
0.00 r 1 1 1 1 1 1 1 1 1 1 1 1 1 1 A 0.00
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Hyd No. 1 Time (min)

4
Hydrograph Summary Report Hydraf low Hydrographs Extension for AutoCAD® Civil 3D® 2018 by Autodesk, Inc. v12
Hyd.
No.
Hydrograph
type
(origin)
Peak
flow
(cfs)
Time
interval
(min)
Time to
Peak
(min)
Hyd.
volume
(cuft)
Inflow
hyd(s)
Maximum
elevation
(ft)
Total
strge used
(cuft)
Hydrograph
Description
1
Mod. Rational
12.58
1
5
7,547
------
------
------
PROPOSED WITHOUT BMP
Coolwick-Proposed Without BMPs.gpw
Return Period: 10 Year
Thursday, 04 / 30 / 2020

Hydrograph Report
5
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2018 by Autodesk, Inc. v12
Hyd. No. 1
PROPOSED WITHOUT BMP
Hydrograph type
= Mod. Rational
Storm frequency
= 10 yrs
Time interval
= 1 min
Drainage area
= 3.420 ac
Intensity
= 6.029 in/hr
IDF Curve
= Revised-Raleigh.IDF
Target Q
=n/a
* Composite (Area/C) _ [(1.480 x 0.95) + (1.940 x 0.35)] / 3.420
Q (cfs)
14.00
12.00
10.00
NIM
4.00
2.00
Thursday, 04 / 30 / 2020
Peak discharge
= 12.58 cfs
Time to peak
= 5 min
Hyd. volume
= 7,547 cuft
Runoff coeff.
= 0.61 *
Tc by User
= 5.00 min
Storm duration
= 2.0 x Tc
Est. Req'd Storage
=n/a
PROPOSED WITHOUT BMP
Hyd. No. 1 -- 10 Year
Q (cfs)
14.00
12.00
10.00
• 11
4.00
2.00
0.00 y ' ' ' ' ' ' ' ' ' ' ' ' ' ' A 0.00
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Hyd No. 1 Time (min)

Hydrograph Summary Report Hydraf low Hydrographs Extension for AutoCAD® Civil 3D® 2018 by Autodesk, Inc. v12
Hyd.
No.
Hydrograph
type
(origin)
Peak
flow
(cfs)
Time
interval
(min)
Time to
Peak
(min)
Hyd.
volume
(cuft)
Inflow
hyd(s)
Maximum
elevation
(ft)
Total
strge used
(cuft)
Hydrograph
Description
1
Mod. Rational
17.25
1
5
10,352
------
------
------
PROPOSED WITHOUT BMP
Coolwick-Proposed Without BMPs.gpw
Return Period: 100 Year
Thursday, 04 / 30 / 2020

Hydrograph Report
I
N
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2018 by Autodesk, Inc. v12
Hyd. No. 1
PROPOSED WITHOUT BMP
Hydrograph type
= Mod. Rational
Storm frequency
= 100 yrs
Time interval
= 1 min
Drainage area
= 3.420 ac
Intensity
= 8.270 in/hr
IDF Curve
= Revised-Raleigh.IDF
Target Q
=n/a
* Composite (Area/C) _ [(1.480 x 0.95) + (1.940 x 0.35)] / 3.420
Q (cfs)
18.00
15.00
12.00
•m
3.00
Thursday, 04 / 30 / 2020
Peak discharge
= 17.25 cfs
Time to peak
= 5 min
Hyd. volume
= 10,352 cuft
Runoff coeff.
= 0.61 *
Tc by User
= 5.00 min
Storm duration
= 2.0 x Tc
Est. Req'd Storage
=n/a
PROPOSED WITHOUT BMP
Hyd. No. 1 -- 100 Year
Q (cfs)
18.00
15.00
12.00
M
3.00
0.00 v 1 1 1 1 1 1 1 1 1 1 1 1 1 1 A 0.00
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Hyd No. 1 Time (min)

Watershed Model Schematic Hydraflow HydrographsExtension for AutoCAD®Civil 3D®2018byAutodesk,Inc. v12
1
i
3
4
Project: Coolwick- Proposed. gpw

Hydrograph Summary Report Hydraf low Hydrographs Extension for AutoCAD® Civil 3D® 2018 by Autodesk, Inc. v12
Hyd.
No.
Hydrograph
type
(origin)
Peak
flow
(cfs)
Time
interval
(min)
Time to
Peak
(min)
Hyd.
volume
(cuft)
Inflow
hyd(s)
Maximum
elevation
(ft)
Total
strge used
(cuft)
Hydrograph
Description
1
Mod. Rational
7.069
1
5
4,241
------
------
------
PROPOSED POND
2
Reservoir
0.000
1
n/a
0
1
396.75
4,241
Proposed Pond
3
Mod. Rational
2.497
1
5
1,498
------
------
------
PROPOSED POND
4
Combine
2.497
1
5
1,498
2, 3
------
------
COMBINED SITE
Coolwick-Proposed.gpw
Return Period: 2 Year

Hydrograph Report
Hydraf low Hydrographs Extension for AutoCADO Civil 3D0 2018 by Autodesk, Inc. v12
Hyd. No. 4
COMBINED SITE
Hydrograph type
= Combine
Peak discharge
= 2.497 cfs
Storm frequency
= 2 yrs
Time to peak
= 5 min
Time interval
= 1 min
Hyd. volume
= 1,498 cuft
Inflow hyds.
= 2, 3
Contrib. drain. area
= 1.290 ac
Q (cfs)
3.00
2.00
1.00
0.00 " 1'
0 1 2
— Hyd No. 4
COMBINED SITE
Hyd. No. 4 -- 2 Year
3 4 5 6
Hyd No. 2
7 8 9 10 11
Hyd No. 3
12 13 14
Q (cfs)
3.00
2.00
1.00
V 0.00
15
Time (min)

4
Hydrograph Summary Report Hydraf low Hydrographs Extension for AutoCAD® Civil 3D® 2018 by Autodesk, Inc. v12
Hyd.
No.
Hydrograph
type
(origin)
Peak
flow
(cfs)
Time
interval
(min)
Time to
Peak
(min)
Hyd.
volume
(cuft)
Inflow
hyd(s)
Maximum
elevation
(ft)
Total
strge used
(cuft)
Hydrograph
Description
1
Mod. Rational
9.265
1
5
5,559
------
------
------
PROPOSED POND
2
Reservoir
0.000
1
n/a
0
1
396.99
5,559
Proposed Pond
3
Mod. Rational
3.273
1
5
1,964
------
------
------
PROPOSED POND
4
Combine
3.273
1
5
1,964
2, 3
------
------
COMBINED SITE
Coolwick-Proposed.gpw
Return Period: 10 Year

5
Hydrograph Report
Hydraf low Hydrographs Extension for AutoCADO Civil 3D0 2018 by Autodesk, Inc. v12
Hyd. No. 4
COMBINED SITE
Hydrograph type
= Combine
Peak discharge
= 3.273 cfs
Storm frequency
= 10 yrs
Time to peak
= 5 min
Time interval
= 1 min
Hyd. volume
= 1,964 cuft
Inflow hyds.
= 2, 3
Contrib. drain. area
= 1.290 ac
Q (cfs)
4.00
3.00
2.00
1.00
0.00 -A
0
COMBINED SITE
Hyd. No. 4 -- 10 Year
Q (cfs)
4.00
3.00
2.00
1.00
0.00
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Time (min)
Hyd No. 4 Hyd No. 2 Hyd No. 3

Hydrograph Summary Report Hydraf low Hydrographs Extension for AutoCAD® Civil 3D® 2018 by Autodesk, Inc. v12
Hyd.
No.
Hydrograph
type
(origin)
Peak
flow
(cfs)
Time
interval
(min)
Time to
Peak
(min)
Hyd.
volume
(cuft)
Inflow
hyd(s)
Maximum
elevation
(ft)
Total
strge used
(cuft)
Hydrograph
Description
1
Mod. Rational
12.82
1
5
7,692
------
------
------
PROPOSED POND
2
Reservoir
6.341
1
13
2,060
1
397.16
6,481
Proposed Pond
3
Mod. Rational
4.529
1
5
2,718
------
------
------
PROPOSED POND
4
Combine
9.019
1
12
4,777
2, 3
------
------
COMBINED SITE
Coolwick-Proposed.gpw
Return Period: 100 Year

I
U
Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2018 by Autodesk, Inc. v12
Hyd. No. 4
COMBINED SITE
Hydrograph type
= Combine
Peak discharge
= 9.019 cfs
Storm frequency
= 100 yrs
Time to peak
= 12 min
Time interval
= 1 min
Hyd. volume
= 4,777 cuft
Inflow hyds.
= 2, 3
Contrib. drain. area
= 1.290 ac
Q (cfs)
10.00
RIM
4.00
2.00
0.00
0 2
Hyd No. 4
COMBINED SITE
Hyd. No. 4 -- 100 Year
4 6 8 10
Hyd No. 2
12 14 16
Hyd No. 3
18 20 22
Q (cfs)
10.00
4.00
2.00
0.00
24
Time (min)

APPENDIX D
SNAP Tool Calculations
Page 9 July 21, 2020

Project Information
Project Name:
Coolwick Warehouse
Submission Date:
07/16/2020
Project Area (ft):
209,089 ft2
Disturbed Area (ft):
145,490 ftz
Commercial
Development - New
no
Development Land Use Type:
Development Activity Type:
Designated Downtown Area?
Project Location/Address:
80 Weathers Street
County:
Franklin
Local Jurisdiction:
Youngsville
Project Latitude Coordinates:
36D 01M 45.04S N
Project Longitude Coordinates:
78D 29M 55.235 W
Precipitation Station:
Franklin
Physiographic Region:
Piedmont
Nutrient Management Watershed:
Neuse
Subwatershed:
Neuse - 03020201
Phosphorus Delivery Zone:
Neuse - Upper
Nitrogen Delivery Zone:
Neuse - Upper
Josh Crumpler 919-413-1704 josh @crumplerconsuI
Project Designer and Contact Phone
Number / Email:
Part of Common Development Plan?
no
Project Owner Type:
Private
Project Description:
Construction of two 10,OOOsf warehouses

Rv= 0.05 + (0.009 * 1)
where I = percent impervious (%)
Average Annual Pollutant Load, L
L=(Pi *R *(P/12))*(C*A*2.72)
where C = event mean concentration (mg/L)
Pre -Project: I
A =
4.8000
a c
P =
54.15
in.
V =
42458
ft3
1=
0%
R =
0.05
PI =
0.9
CTN =
0.97
mg/L
CTP =
0.03
mg/L
LTN =
2.57
Ib/yr
LTP =
0.08
Ib/yr
Project Area Land Cover Characteristics
PROJECT AREA LAND COVERS
Roof _ _
Roadway
TN TP
EMC EMC
(mg/L) (mg/L)
Pre- Post -
Project Project
Area (ft) Area (ft)
1.18
0.11
0
25,400
1.64
0.34
0
Parking/Driveway/Sidewalk
1.42
0.18
0
39,188
Protected Forest
0.97
0.03
209,089
63,599
Other Pervious/Landscaping
2.48
1.07
74,902
CUSTOM LAND COVER 1
CUSTOM LAND COVER 2
CUSTOM LAND COVER 3
LAND TAKEN UP BY SCM
1.18
0.11
0
6,000
LAND COVER AREA CHECK
Net Change of Land Covers (ft): 145,490
Total Project Area Entered (ftZ):
Total Pre -Project Calculated Area (ftZ):
Total Post -Project Calculated Area (ftZ):
Equations Used and Project Area Calculations
SIMPLE METHOD Stormwater Runoff Volume Generated, V
Runoff Coefficient, R v V = Pi * Rv * (P/12) * A
where A = drainage area (ft)
Pj = fraction of rain events with runoff
P = average annual rainfall depth (in)
209,089
209,089
209,089
Project:
A = 4.8000
P = 54.15
V = 301684
1 = 34%
Rv = 0.36
Pj = 0.9
CTN = 1.36
CTP = 0.19
LTN = 25.56
LTP = 3.58
ac
in.
ft3
mg/L
mg/L
Ib/yr
Ib/yr

3. SCM Characteristics
SCM Characteristics
Catchment ID
SCM ID
Type of SCM
Predominant hydrologic soil
group at SCM location
SCM Description
Design Storm Size (inches/24hrs)
Percent of Full Size
Hydrologic Value - Percent
Annual Effluent
Hydrologic Value - Percent
Annual Overflow
Hydrologic Value - Percent
Annual ET/Infiltrated
SCM Effluent TP EMC (mg/L)
SCM Effluent TN EMC (mg/L)
SCM Land Cover TP EMC (mg/L)
SCM Land Cover TN EMC (mg/L)
Drains to SCM ID
1
101
Wet Pond per MDC
B
Wet Pond per MDC
2.87
100
68
1
102
1
103
16%
17%
0.15
1.22
0.11
1.18
0

3. SCM Characteristics
Catchment Routing
(Source Catchment)
Catchments Draining to
Catchments Draining to
Catchments Draining to
SCM 101
SCM 102
SCM 103
Catchment 1
no
Catchment 2
no
Catchment 3
no
Catchment 4
no
Catchment 5
no
Catchment 6
no
SCM ID:
103
Area7Draining Directly to
Area Draining Directly to
Area Draining Directly to
SCM Drainage Area Land Covers
101 (ft2)
SCM 102 (ft2)
SCM 103 (ft2)
Roof _
Roadway
Parking/Driveway/Sidewalk
Protected Forest
Other Pervious/Landscaping
CUSTOM LAND COVER 1
CUSTOM LAND COVER 2
CUSTOM LAND COVER 3
LAND TAKEN UP BY SCM
OTAL AREA DRAINING TO SCM
(ft):
ICATCHMENT AREA (ft):
32,534
28,553
3-me
92,487 I 0 I 0
92,487

3. SCM Characteristics
Catchment Routing
(Source Catchment)
Catchment 1
Catchment 2
Catchment 3
Catchment 4
Catchment 5
Catchment 6
SCM ID:
SCM Drainage Area Land Covers
Roof
Roadway
Total Land Use Area
2
Treated By All SCMs (ft)
Allowable Total Land Use
Area to be Treated Based
on Post-Proiect Areas (ft2)
25,400
Post -Project Untreated
2
Land Area (ft )
0
25,400
0
0
0
Parking/Driveway/Sidewalk
32,534
39,188
6,654
Protected Forest
0
63,599
63,599
Other Pervious/Landscaping
28,553
74,902
46,349
CUSTOM LAND COVER 1
0
0
0
CUSTOM LAND COVER 2
0
0
0
CUSTOM LAND COVER 3
ND TAKEN UP BY SCM
OTAL AREA DRAINING TO SCM
2
f(ft) :
1 CATCHMENT AREA (ft):
0
0
0
0
6,000
6,000
92,487
209,089
116,602

Project Summary
Project Name:
Coolwick Warehouse
209,089 ft 4.8000 acres Submission Date:
145,490 ft2 3.3400 acres July 16, 2020
Project Area (ft):
Disturbed Area (ft):
County:
Franklin
Local Jurisdiction:
Youngsville
Development Land Use Type:
Commercial
Owner Type:
Private
Development Activity Type:
Development - New
Designated Downtown Area?
no
Nutrient Management Watershed:
Neuse
Subwatershed:
Neuse - 03020201
Phosphorus Delivery Zone:1
Neuse - Upper
Nitrogen Delivery Zone:
Neuse - Upper
Phosphorus Delivery
Factor (%):
100%
Nitrogen Delivery
Factor (%):
100%
Phosphorus Loading Rate Target (Ib/ac/yr):
0.75
Nitrogen Loading Rate Target (Ib/ac/yr):
5.32
Phosphorus Load Target at Site (lb/yr):
3.58
Nitrogen Load Target at Site (lb/yr):
25.56
Phosphorus Load Leaving Site w/SCMs (lb/yr):
2.95
Nitrogen Load Leaving Site w/SCMs (lb/yr):
20.81
P Offsite Buy -Down Threshold Loading Rate (lb/ac/yr):
N/A
N Offsite Buy -Down Threshold Loading Rate
N/A
Total P Load Reduction Needed (lb/yr):
0.00
Total N Load Reduction Needed (lb/yr):
0.00
P Load Treatment Balance at Site (lb/yr):
-0.63
N Load Treatment Balance at Site (lb/yr):
-4.75
P Load Treatment Balance at Lake (lb/yr):
-0.63
N Load Treatment Balance at Lake (lb/yr):
-4.75
Pre -Project Post -Project Post -Project Post -Project
ki •4& .. & C __ - - . r:a_ r:a_ :a_ . :aV r .. T __a_J Post -Project
FgUL1 II=HL LA VI JU11111101 y vvnvic. ILC vvnvic. ILC vVIIVIC ILCVvIuNI OaIVI-IIcaaau
Conditions without SCMs SCMs Area
Percent Impervious (for runoff calculation) (%) 0.0% 33.8% 33.8% 69.1%
Percent Built -Upon Area (BUA) (%) 0.0% 30.9% 30.9% 62.6%
Untreated Area
5.7%
5.7%
Annual Runoff Volume (W/ r)
42,458
301,684
258,852
210,853
47,999
Annual Runoff % Change (relative to pre-D)
0%
611%
510%
Total Nitrogen EMC (mg/L)
0.97
1.36
1.29
1.24
1.51
Total Nitrogen Load Leaving Site (lb/yr)
2.57
25.56
20.81
16.29
4.51
Total Nitrogen Loading Rate (Ib/ac/yr)
0.54
5.32
4.33
7.67
1.69
Total Nitrogen % Change (relative to pre-D)
0%
894%
709%
Total Phosphorus EMC (mg/L)
0.03
0.19
0.18
0.15
0.31
Total Phosphorus Load Leaving Site (lb/yr)
0.08
3.58
2.95
2.01
0.94
Total Phosphorus Loading Rate (Ib/ac/yr)
0.02
0.75
0.62
0.95
1 0.35
Total Phosphorus % Change (relative to pre-D)
0%
4401%
3612%

SCM/Catchment Summary
SCM ID and Type Volume TN Out (mg/L) TP Out (mg/L)
Reduction (%)
Catchment 1 16.88% 1.24 0.15
TN Out TP Out TN Reduction (%) TP Reduction (%)
(lbs/oc/yr) (lbs/oc/yr)
7.67 0.95 22.56% 23.76%
101: Wet Pond per MDC
16.88%
1.24
0.15
7.67
0.95
22.56%
23.76%
102: NA
0.00%
0.00
0.00
0.00
0.00
0.00%
0.00%
103: NA
0.00%
0.00
0.00
0.00
0.00
0.00%
0.00%
Catchment 2
0.00%
0.00
0.00
0.00
0.00
0.00%
0.00%
201: NA
0.00%
0.00
0.00
0.00
0.00
0.00%
0.00%
202: NA
0.00%
0.00
0.00
0.00
0.00
0.00%
0.00%
203: NA
0.00%
0.00
0.00
0.00
0.00
0.00%
0.00%
Catchment 3
0.00%
0.00
0.00
0.00
0.00
0.00%
0.00%
301: NA
0.00%
0.00
0.00
0.00
0.00
0.00%
0.00%
302: NA
0.00%
0.00
0.00
0.00
0.00
0.00%
0.00%
303: NA
0.00%
0.00
0.00
0.00
0.00
0.00%
0.00%
Catchment 4
0.00%
0.00
0.00
0.00
0.00
0.00%
0.00%
401: NA
0.00%
0.00
0.00
0.00
0.00
0.00%
0.00%
402: NA
0.00%
0.00
0.00
0.00
0.00
0.00%
0.00%
403: NA
0.00%
0.00
0.00
0.00
0.00
0.00%
0.00%
Catchment 5
0.00%
0.00
0.00
0.00
0.00
0.00%
0.00%
501: NA
0.00%
0.00
0.00
0.00
0.00
0.00%
0.00%
502: NA
0.00%
0.00
0.00
0.00
0.00
0.00%
0.00%
503: NA
0.00%
0.00
0.00
0.00
0.00
0.00%
0.00%
Catchment 6
0.00%
0.00
0.00
0.00
0.00
0.00%
0.00%
601: NA
0.00%
0.00
0.00
0.00
0.00
0.00%
0.00%
602: NA
0.00%
0.00
0.00
0.00
0.00
0.00%
0.00%
603: NA
0.00% 0.00
0.00 0.00
0.00
0.00%
0.00%
SCM rows in red have a data entry error for the SCM that makes an error in the calculation.

Supporting Calculations
R = 0.05 + (0.009 *1),
where I = percent impervious (%)
V=Pi* Rv*A*(P/12),
where A = area of catchment (ft')
P = average annual rainfall depth (in)
L=((P*Pi*R) (12 )) * (C * A * 2.72)
where L = annual pollutant loading (Ibs)
Pi = fraction of rain events that produce runoff (dec)
C = event mean concentration of pollutant (mg/L)
Vout = V;, * (1- Red)
where Vin = inflow volume (ft3)
Red = volume reduction by SCM (%)
Lout = Vout * EMCo t * 6.243E-5
where Vout = outflow volume (ft3),
EMCo t = effluent median concentration (mg/L)
CATCHMENT 1, SCM 101
Type of SCM:
Wet Pond per MDC
Area Treated by SCM (ft):
92,487
Percent Impervious of Contributing Watershed (%):
69%
Runoff Coefficient, Rv:
0.68
Inflow Volume (ft):
253,686
Incoming Total Nitrogen Concentration (mg/L):
1.33
Annual Incoming Total Nitrogen Load (lbs):
21.04
Incoming Total Phosphorus Concentration (mg/L):
0.17
Annual Incoming Total Phosphorus Load (lbs):
2.64
Total Volume Leaving SCM (ft):
210,853
Outgoing Total Nitrogen Concentration (mg/L):
1.24
Annual Outgoing Total Nitrogen Load (lbs):
16.29
Outgoing Total Phosphorus Concentration (mg/L):
0.15
Annual Outgoing Total Phosphorus Load (lbs):
2.01
Annual Volume Reduction by SCM (ft):
42,832
Annual Volume Reduction by SCM (%):
17%
Annual Total Nitrogen Reduction by SCM (%):
22.56%
Annual Total Nitrogen Reduction by SCM (lb):
4.75
Annual Total Phosphorus Reduction by SCM (%):
23.76%
Annual Total Phosphorus Reduction by SCM (lb).
0.63

Nutrient Management Strategy Watershed - Nutrient Offset Credit Reporting Form
Please complete and submit the following information to the local government permitting your development project
to characterize it and assess the need to purchase nutrient offset credits. Contact and rule implementation
information can be found online at.
http://deg.nc.gov/about/divisions/water-resources/planning/nonpoint-source-management/nutrient-offset-
information
PROJECT INFORMATION
Applicant Name: Coolwick, LLC
Project Name: Coolwick Warehouse
Project Address: 80 Weathers Street
Date: (mm/dd/yyyy) 7/16/2020
Development Land Use Type:
Commercial
County: Franklin
Development Activity Type:
Development - New
Pre -Project Built -Upon Area %:
0.00%
Project Latitude:
36D 01M 45.04S
Post -Project Built -Upon Area %:
30.89%
Project Longitude:
78D 29M 55.23S
WATERSHED INFORMATION
Nutrient Management Watershed:
Neuse
Subwatershed:
Neuse - 03020201
Nitrogen Delivery Zone:
Neuse - Upper
Phosphorus Delivery Zone:
Neuse - Upper
N Offsite Threshold Rate (lb/ac/yr):
N/A
P Offsite Threshold Rate (lb/ac/yr):
N/A
Nitrogen Delivery Factor:
100%
Phosphorus Delivery Factor:
100%
NUTRIENT OFFSET REQUEST
Nitrogen Load Offset Needs
(A)
(B)
(C)
(D)
(E)
(F)
(G)
(H) (L) (Where
Applicable)
Untreated
Treated
Loading Rate
Reduction
Project Size
Offset
Delivery
State Buy Local Gov't
Loading Rate
Loading Rate
Target
Need
(ac)
Duration (yrs)
Factor (%)(Ibs)
Down Amount Buy Down
(Ibs/ac/yr)
(Ibs/ac/yr)
(Ibs/ac/yr)
(Ibs/ac/yr)
Amount (Ibs)
B-C
D*E*F*G
5.32
1 4.33
1 5.32
1 -0.99
4.8000
30
100%
0.00
Phosphorus Load Offset Needs
(A)
(B)
(C)
(D)
(E)
(F)
(G)
(H) (L) (Where
Applicable)
Untreated
Treated Load
Loading Rate
Reduction
Project Size
Offset
Delivery
State Buy Local Gov't
Load Rate
Rate
Target
Need
(ac)
Duration (yrs)
Factor (%)
Down
Down Amount Buy Down
(Ibs/ac/yr)
(Ibs/ac/yr)
(Ibs/ac/yr)
(Ibs/ac/yr)
Amount (Ibs)
B-C
D*E*F*G
0.75
0.62
0.75
-0.13
4.8000
30
100%
0.00
LOCAL GOVERNMENT AUTHORIZATION
Local Government Name: Y
Staff Name:
Staff Emai
Local Government Authorizing Signature:

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
PROJECT INFORMATION
1 I Project Name
2 1Proiect Area (ac)
3 Coastal Wetland Area (ac)
4 Surface Water Area (ac)
5 Is this project High or Low Density?
6 Does this protect use an off -site SCM?
Coolwick Warehouse
4.8
No
COMPLIANCE WITH 02H .1003(4)
7
Width of vegetated setbacks provided (feet)
10
8
Will the vegetated setback remain vegetated?
Yes
9
Is BUA other that as listed in .1003(4)(c-d) out of the setback?
Yes
10
Is streambank stabilization proposed on this project?
No
NUMBER AND TYPE OF SCMs:
11
Infiltration System
0
12
Bioretention Cell
0
13
Wet Pond
1
14
Stormwater Wetland
0
15
Permeable Pavement
0
16
Sand Filter
0
17
Rainwater Harvesting (RWH)
0
18
JGreen Roof
0
19
Level Spreader -Filter Strip (LS-FS)
0
20
Disconnected Impervious Surface (DIS)
0
21
Treatment Swale
0
22
Dry Pond
0
23
StormFilter
0
24
Silva Cell
0
25
Bayfilter
0
26
Filterra
0
FORMS LOADED
DESIGNER CERTIFICATION
27
Name and Title:
Joshua Crumpler, PE
28
Organization:
Crumpler Consulting Services, PLLC
29
Street address:
2308 Ridge Road
30
City, State, Zip:
Raleigh, NC 27612
31
Phone number(s):
919-413-1704
32
Email:
[e-mail]
Certification Statement:
I certify, under penalty of law that this Supplement-EZ form and all supporting information were prepared under my direction or
supervision; that the information provided in the form is, to the best of my knowledge and belief, true, accurate, and complete; and
that the engineering plans, specifications, operation and maintenance agreements and other supporting information are consistent
with the information provided here.
'�<<r�rrrrrrr+r�
CAR
EAL
034994
�:S•fi •'IA
V NE ��QV
A . C0
Signat a of Designer
Date

DRAINAGE AREAS
1
Is this a high density project?
Yes
2
If so, number of drainage areas/SCMs
1
3
Is all/part of this project subject to previous rule
versions?
No
FORMS LOADED
DRAINAGE AREA INFORMATION
Entire Site
1
4
Type of SCM
Wet Pond
Wet Pond
5
Total BUA in project (sq ft
64588 sf
58391 sf
6
New BUA on subdivided lots (subject to permitting)
(sq ft)
7permitting)
New BUA outside of subdivided lots (subject to
s
8
Offsite - total area (sq ft)
9
Offsite BUA s ft
10
Breakdown of new BUA outside subdivided lots:
- Parking (sq ft
2705 sf
2705 sf
- Sidewalk (sq ft)
669 sf
669 sf
- Roof (sq ft)
25400 sf
25400 sf
- Roadway (sq ft)
35893 sf
29607 sf
- Future (sq ft
- Other, please specify in the comment box
below (sq ft)
11
New infiltrating permeable pavement on
Isubdivided lots (sq ft
12
New infiltrating permeable pavement outside of
subdivided lots (sq ft)
13permitting)
Exisitng BUA that will remain (not subject to
s ft
14
Existing BUA that is already permitted (sq ft)
15
Existing BUA that will be removed (sq ft
16553 sf
16553 sf
16
Percent BUA
44%
63%
17
IDesign storm inches
3 in
3 in
18
Design volume of SCM (cu ft)
18647 cf
19
Calculation method for design volume
SA/DA
ADDITIONAL INFORMATION
20
Please use this space to provide any additional information about the
drainage area(s):

WET POND
1 Drainage area number 1
2 Design volume of SCM (cu ft) 18647 cf
(;FNFRAI Mnr FRnm O2M _inrn
3
Is the SCM sized to treat the SW from all surfaces at build -out?
No
4
Is the SCM located away from contaminated soils?
Yes
5
What are the side slopes of the SCM (H:V)?
3:1
6
Does the SCM have retaining walls, gabion walls or other engineered
side slopes?
No
7
Are the inlets, outlets, and receiving stream protected from erosion
(10-year storm)?
Yes
8
Is there an overnow or bypass for inflow volume in excess of the
design volume?
Yes
9
What is the method for dewatering the SCM for maintenance?
Drawdown Orifice
10
If applicable, will the SCM be cleaned out after construction?
Yes
11
Does the maintenance access comply with General MDC (8)?
Yes
12
Does the drainage easement comply with General MDC (9)?
Yes
13
If the SCM is on a single family lot, does (will?) the plat comply with
General MDC (10)?
No
14
Is there an O&M Agreement that complies with General MDC (11)?
Yes
15
Is there an O&M Plan that complies with General MDC (12)?
Yes
16
Does the SCM follow the device specific MDC?
Yes
171
Was the SCM designed by an NC licensed professional?
Yes
WET POND MDC FROM 02H .1053
18
Method used
SA/DA
19
Has a stage/storage table been provided in the calculations?
Yes
20
Elevation of the excavated main pool depth (bottom of sediment
removal) (fmsl)
391.50
21
Elevation of the main pool bottom -(top of sediment removal) (fmsl)
-
221
Elevation of the bottom of the vegetated shelf (fmsl)
396.00
23
Elevation of the permanent pool (fmsl)
396.00
24
Elevation of the top of the vegetated shelf (fmsl)
397.00
25
Elevation of the temporary pool (fmsl)
397.50
26
Surface area of the main permanent pool (square feet)
3570:1
27
Volume of the main permanent pool (cubic feet)
13203 cf
28
Average depth of the main pool (feet)
3.00 ft
29
Average depth equation used
Equation 2
30
If using equation 3, main pool perimeter (feet)
-
31
If using equation 3, width of submerged veg. shelf (feet)
32
Volume of the forebay (cubic feet)
2803 cf
33
Is this 15-20% of the volume in the main pool?
Yes
34
Clean -out depth for forebay (inches)
6 in
351
Design volume of SCM (cu ft)
18647 cf
36
Is the outlet an orifice or a weir?
Orifice
37
If orifice, orifice diameter (inches)
2 in
38
If weir, weir height (inches)
39
If weir, weir length (inches)
-
40
Drawdown time for the temporary pool (days)
2.5
41
Are the inlet(s) and outlet located in a manner that avoids short-
circuiting?
Yes
42
Are berms or baffles provided to improve the flow path?
No
43
Depth of forebay at entrance (inches)
48 in
44
Depth of forebay at exit (inches)
36 in
45
Does water flow out of the forebay in a non -erosive manner?
Yes
46
Width of the vegetated shelf (feet)
6 ft
47
Slope of vegetated shelf (H:V)
6:1
48
Does the orifice drawdown from below the top surface of the
permanent pool?
No
49
Does the pond minimize impacts to the receiving channel from the 1-
yr, 24-hr storm?
Yes
50
Are fountains proposed? (If Y, please provide documentation that
MDC(9) is met.)
No
51
Is a trash rack or other device provided to protect the outlet system?
Yes
52
Are the dam and embankment planted in non -clumping turf grass?
Yes
53
Species of turf that will be used on the dam and embankment
54
Has a planting plan been provided for the vegetated shelf?
No
ADDITIONAL INFORMATION
55
Please use this space to provide any additional information about the
wet pond(s):
Wet Pond

APPENDIX E
Wetland and Stream Map
Page 10 July 21, 2020

N Q Study Area Weathers Street Site
O CAROLINA Franklin County, NC
ECOSYSTEMS Feet �� USGS Mapped Stream
0 80 160 Wetlands 36.028594,-78.500018
September 2019 Field Map
2017 NC Statewide Aerial Photography

APPENDIX F
Drainage Area Maps
Page 1 1 July 21, 2020

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1. BOUNDARY AND EXISTING CONDITIONS SURVEY PROVIDED BY B.L. SCOTT
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2. A PORTION OF THE PROPERTY IS LOCATED IN ZONE X THAT IS LOCATED
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1. BOUNDARY AND EXISTING CONDITIONS SURVEY PROVIDED BY B.L. SCOTT
LAND SURVEYING DATED 08-08-19.
2. A PORTION OF THE PROPERTY IS LOCATED IN ZONE X THAT IS LOCATED
WITHIN THE 0.2% ANNUAL CHANCE ZONE. THE REMAINING PORTIONS OF
THE PROPERTY IS LOCATED IN ZONES X (AREA DETERMINED TO BE
OUTSIDE THE 0.2% ANNUAL CHANCE AND FUTURE 1 % ANNUAL CHANCE
FLOODPLAIN) BASED ON THE FEMA MAP NUMBER 3720184200L DATED
APRIL , 2013.
3. ONSITE WETLANDS HAVE BEEN IDENTIFIED WITHIN THE PROJECT OR
PARCEL AS SHOWN. WETLANDS INVESTIGATION PERFORMED BY
CAROLINA ECOSYSTEMS IN SEPTEMBER 2019.
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