SW6230103_Stormwater Narrative_20231020

STORMWATER MANAGEMENT
AND
TEMPORARY EROSION CONTROL
for
CARTER FARMS SUBDIVISION
PHASE I
Submittal to:
NCDEQ PUBLIC WATER SUPPLY SECTION
HOKE COUNTY, NORTH CAROLINA
Submittal date:
May 18, 2022
Owner/ Developer:
Rheibeck Investments, LLC.
3727 Legion Road
Hope Mills, NC 28348
Contact: Geoff Becker
Phone: [phone]
Prepared by:
Averette Engineering Co., P.A.
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TABLE OF
CONTENTS
SECTION PAGE
I. EXISTING CONDITIONS
A. PROPERTY ....................................................................................................1
B. WATERSHED .................................................................................................2
C. JURISDICTIONAL WATERS.................................................................................2
D. FEMA FLOOPLAIN... ....................................................................................2
E. SOILS............................................................................................................2
II. AGENCY STORMWATER REQUIREMENTS
A. Hoke County.............................................................................................2
B. NCDEQ .........................................................................................................3
III. PROPOSED IMPROVEMENTS
A. PROJECT DESCRIPTION.....................................................................................3
B. LAND DISTURBANCE AND EROSION CONTROL.......................................3
C. IMPERVIOUS SURFACE ...................................................................................3
D. DRAINAGE AND STORMWATER MANAGEMENT.......................................4
APPENDICES
A. Computations
Minor System
Grass Conveyance Swales
Erosion Control
B. Maps
Inlet Drainage Area
Erosion Control Drainage Area
C. Soil Survey Map
D. FEMA FIRM Map
E. USGS MAP
F. STORMWATER FORMS
SUPPLEMENT-EZ
OPERATION &MAINTENANCE AGREEMENT
BMP SUPPLEMENT FORMS

I. EXISTING CONDITIONS
A. PROPERTY
The proposed project site is 28.11 AC project consisting of PIN#'s
7947-30-00-1348, 794730001062, 794730001316, 794730001294,
794730001295, 794730001293 respectively in Hoke County. The property
is currently undeveloped farm land with no impervious surfaces. The
property has a cell phone tower that is to be decommissioned as part of
phase 2.
The following is a summary of the adjacent properties:
To the north, commercial chicken farm(zoning RA-20)
To the south, single family (zoning RA-20)
To the west, undeveloped (zoning RA-20)
To the east, single family (zoning RA-20)
See Figure 1 below for an aerial view of the property for the proposed Carter
Farm Subdivision project (Site).
Figure ]:Aerial view of pre-developed site
�s
3 Za
Stormwater Impact Analysis-Carter Farms Subdivision
Page 1 1 4

B. WATERSHED
The site is located in the Mill Creek Watershed and Cape Fear River
Basin. The NCDEQ Stream Index for Mill Creek is 18-31-20 and Stream
Classification for Mill Creek is `B'.
C. JURISDICTIONAL WATERS
There are no jurisdictional streams located on the site. There are no
impacts proposed with this project to jurisdictional streams or
wetlands.
D. FEMA FLOODPLAIN
There are FEMA mapped floodplains located on the site per FIRM Panel
3710947300J, effective date Oct. 17, 2006. See Appendix D for FEMA FIRM
maps. No floodplains will be impacted by the development of the site
E. SOILS
Refer to Appendix C for the NRCS map showing anticipated on-site soils.
II. AGENCY STORMWATER REQUIREMENTS
A. Hoke County
Section 3.7 `Storm Drainage Not in Public Streets" of the Hoke County
Subdivision Ordinance details the requirements for managing
stormwater from new construction sites.
Section 3.3 `Streets" of the Hoke County Subdivision Ordinance details
the requirements for managing stormwater from new construction sites
per NCDOT requirements.
Stormwater Impact Analysis-Carter Farms Subdivision
Page 2 1 4

B. NCDEQ
Hoke County is a `tipped' county and new projects located within the
county must meet NCDEQ Post Construction Stormwater Phase 2
regulations. Site requirements for stormwater control are different if the
proposed development is `high density' (greater than 24%impervious) or
`low density' (less than 24%impervious).
III. PROPOSED IMPROVEMENTS
A. PROJECT DESCRIPTION
The proposed project will create fifteen (15) single family lots (min 20,000
sf) in phase 1. The proposed project will add additional roads the Hoke
County road system. The design follows the Preliminary Plat that was
recently approved by Hoke County. As part of this project, public water
will be extended to serve the new lots.
B. LAND DISTURBANCE AND EROSION CONTROL
The proposed disturbed area for the proposed project is 9.5 AC +/-. A
NCDEQ Land Disturbance (Erosion Control) Permit will be obtained prior to
beginningwork.
C. IMPERVIOUS SURFACE
The proposed total amount of impervious surfaces for this project is 7.68 AC.
Phase 1 contains 2.39 ac of the total project impervious. This includes
pavement and curb & gutters in the public R/W and driveways and
rooftops on each lot. The resulting percent impervious (or built-upon)
of 22.2% of the total project area. Phase 1 will result in a percent impervious
of 13.0% of the total project area. A maximum amount of 4,738 SF of
impervious area is allocated to each lot. Thus, this development is
classified as `low density' under NCDEQ Phase II regulations.
Stormwater Impact Analysis-Carter Farms Subdivision
Page 3 1 4

D. DRAINAGE AND STORMWATER MANAGEMENT
i. Roadway Drainage-Minor System
The proposed roadway will have curb and gutter. Catch basins in the
gutter line will provide the roadway drainage. Catch basins were
spaced based on gutter spread not exceeding one-half lane width
during a 4 in/hr storm (NCDOT guidelines). The minor pipe system is
sized based on 10-year storm flow and cross-pipes are sized based on
25-year storm flow not exceeding the hydraulic capacity of each pipe
segment (as open channel flow, that is, non- pressure flow).
ii. Grass Conveyance Swales
As stated in Section III. C. above, proposed impervious is less than 24% and,
therefore is classified as `Low Density' per NCDEQ regulations.
Per NCDEQ guidance, Curb outlet swales are proposed to receive runoff
collected by the catch basins in the road system to control the runoff before
being discharged from the site. The curb outlet swale has a longitudinal
slope of 0.0%that discharge through a swale level spreader to the north.
There is one proposed curb outlet swale (PC#1), that accounts for the runoff
for swales #2 &3 (PC#2, PC#3).The proposed curb outlet swale has a length
greater than 100 LF per post stormwater rules. A routing analysis of the swales
was performed to account for infiltration of the soils and the available
volume in the swales since the bottom elevation of the swale PC#1 is below
the outlet elevation. The lower bottom elevation provides retention of the 25-
yr storm which reduces the outflow through the level spreader by 15.2 CFS.
The post development flow into swale PC#1 is 33.94 cfs (18.4 ac, I=calc. TC,
c=0.35). The pre-development flow is 13.80 cfs (6.8 ac, I=calc. TC, c=0.30).
The retention within the swale reduces the post-development flow to 14.54
CFS as compared to pre-development flow at 13.80 CFS (1.34 CFS increase).
In addition to the flow reduction the level spreader reduces the outlet
velocity to 1.18 ft/s.
iii. Methodology and computations
Refer to Appendix A for storm drainage and stormwater management
computations. Hydrologic computations were based on the Rational
Method for storm drainage and SCS method for stormwater
management. Rainfall intensity was determined based on data of the
closest rainfall gauge listed on the NOAA website. Drainage areas
were delineated based on a combination of field and LIDAR
topography. A time of concentration of 5 min is used for all calculations
unless the overall flow length exceeds 1000 ft.
Stormwater Impact Analysis-Carter Farms Subdivision
Page 4 1 4

APPENDIX A
Computations
Minor System
Grass Conveyance Swales
Erosion Control

Minor System

Upstream Inlet Inlet Rainfall Pipe Capacity Gutter Gutter Gutter
Drainage Area Pipe Diameter Total Pipe Flow Total System Pipe Slope Pipe Invert Pipe Invert Elevation(Top) Inlet Elevation Flow(Total Flow(Total
Inlet ID Inlet ID Runoff (acres) Intensity*(in/h) (in) Pipe Material Pipe Length(ft) (Full Flow) (ft'/s)(1) Flow(ft'/s) (ft/ft) (Upstream)(ft) (Downstream)(ft) Inlet ID (ft)(3) (Invert)(ft) Inlet Type 4 iNhr
Intercepted) Bypassed)
Coeficient (5) (ft'/s) (ft'/s)(2)
(ft'/s) (ft'/s)
FES 104 CB 103 0.35 3.20 5.99 18 Class II I RCP 20.00 19.70 6.71 6.71 0.0300 199.63 199.03 FES 104 202.00 199.63 NCDOT 840.19 - -
CB 103 CB 102 0.70 0.25 7.97 24 Class III RCP 24.00 17.32 1.39 8.10 0.0050 197.63 197.51 CB 103 202.53 197.63 NCDOT 840.03 0.82 0.47
CB 102 JB 101 0.70 0.20 7.97 24 Class III RCP 14.50 17.32 1.12 922 0.0050 197.51 197.41 CB 102 202.53 197.51 NCDOT 840.03 0.66 0.38
DI 101(6) FES 100 - - - 24 Class I II RCP 85.00 17.32 - 922 0.0050 197.42 197.00 DI 101(6) 202.40 197.42 NCDOT 840.19 - - -
CB 206 CB 205 0.35 0.50 7.97 15 Class I II RCP 166.00 6.99 1.39 1.39 0.0102 206.36 204.66 CB 206 204.81 206.36 NCDOT 840.03 0.70 0.54 0.16
CB 205 CB 203 0.35 0.70 7.97 15 Class III RCP 348.00 6.99 1.95 3.35 0.0097 204.66 201.30 CB 205 204.81 204.66 NCDOT 840.03 1.14 0.81 0.33
FES 204 CB 203 0.35 2.10 8.89 15 Class III RCP 2000. 12.12 6.53 6.53 0.0300 201.94 201.34 FES 204 204.81 201.94 NCDOT 840.03 2.94 1.41 0.65
CB 203 CB 202 0.70 0.19 7.97 24 Class III RCP 24.00 21.91 1.06 10.94 0.0083 200.34 200.14 CB 203 204.81 200.34 NCDOT 840.03 0.86 0.48 0.12
CB 202 JB 201 0.70 0.40 7.97 24 Class III RCP 14.50 2035. 2.23 13.17 0.0069 200.14 200.04 CB 202 204.81 200.14 NCDOT 840.03 1.12 0.46 0.10
DI 201(6) FES 200 - - - 24 Class III RCP 85.00 2079. - 13.17 0.0072 200.04 199.43 DI 201(6) 205.01 200.04 NCDOT 840.19 - - -
Notes
1 Storm System Sizing based on 10-yr Storm
2 Gutter Spread Calculations based on Storm Intensity of 4 inthr
3 CB(Catch Basin)Top Elevation is BOC
4 Gutter Spread Width is measured from Edge of Pavement
5 Storm System Sizing based on 25-yr Storm-for cross pipe drainage
6 Inlet is for secondary collection-No intial flow captured.

Culvert Report
Hydraflow Express Extension for AutoCADO Civil 3D0 2009 by Autodesk, Inc. Wednesday,Sep 21 2022
FES 104
Invert Elev Dn (ft) = 199.03 Calculations
Pipe Length (ft) = 20.00 Qmin (cfs) = 6.71
Slope (%) = 3.00 Qmax (cfs) = 6.71
Invert Elev Up (ft) = 199.63 Tailwater Elev (ft) = Normal
Rise (in) = 18.0
Shape = Cir Highlighted
Span (in) = 18.0 Qtotal (cfs) = 6.71
No. Barrels = 1 Qpipe (cfs) = 6.71
n-Value = 0.012 Qovertop (cfs) = 0.00
Inlet Edge = Projecting Veloc Dn (ft/s) = 8.35
Coeff. K,M,c,Y k = 0.0045, 2, 0.0317, 0.69, 0.5 Veloc Up (ft/s) = 5.32
HGL Dn (ft) = 199.73
Embankment HGL Up (ft) = 200.64
Top Elevation (ft) = 202.50 Hw Elev (ft) = 201.14
Top Width (ft) = 18.00 Hw/D (ft) = 1.01
Crest Width (ft) = 10.00 Flow Regime = Inlet Control
Elev(ft) FES 104 Hw Depth(ft)
203.00 3.37
202.00 2.37
201.00 net control 1.37
200.00 0.37
199.00 -0.63
198.00 L -1.63
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28
Cir Culvert HGL Embank Reach(ft)

Culvert Report
Hydraflow Express Extension for AutoCADO Civil 3DO 2009 by Autodesk, Inc. Wednesday,Sep 21 2022
FES 204
Invert Elev Dn (ft) = 201 .34 Calculations
Pipe Length (ft) = 20.00 Q m i n (cfs) = 6.53
Slope (%) = 3.00 Qmax (cfs) = 6.53
Invert Elev Up (ft) = 201 .94 Tailwater Elev (ft) = Normal
Rise (in) = 18.0
Shape = Cir Highlighted
Span (in) = 18.0 Qtotal (cfs) = 6.53
No. Barrels = 1 Qpipe (cfs) = 6.53
n-Value = 0.012 Qovertop (cfs) = 0.00
Inlet Edge = Projecting Veloc Dn (ft/s) = 8.29
Coeff. K,M,c,Y,k = 0.0045, 2, 0.0317, 0.69, 0.5 Veloc Up (ft/s) = 5.26
HGL Dn (ft) = 202.03
Embankment HGL Up (ft) = 202.93
Top Elevation (ft) = 204.84 Hw Elev (ft) = 203.42
Top Width (ft) = 18.00 Hw/D (ft) = 0.99
Crest Width (ft) = 10.00 Flow Regime = Inlet Control
Elev(ft) FES 204 Hw Depth(ft)
205.00 3.06
204.00 2.06
Inlet control
203.00 1.06
202.00 0.06
201.00 -0.94
200.00 -1.94
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28
Cir Culvert HGL Embank Reach(ft)

Grass Conveyance Swales

Permanent Channel# 1 =>DA# PD 1
Calculate Flow-Rational Method
25-VrStorm
Qzs=CIA C= 0.35
1= 5.92 in/hr CALCTc
Qzs= 38.12 A= 18.40 ac
Channel Slope-- 0.00
Channel Depth— 2.50
Channel Bottom Width= 4.00
Side Slopes= 3.00
Veloci 2.25
Soil Type sandy loam Slopes=0-10%
Channel Lining
Shear Calculation
T=yds y= 62.4 Ibs
dwae
T= 0.112321bs/ft2 s= ft/ft
Temporary=NAG S75BN
Permanent=Fescue(1.0 Ibs/ft
Permanent Channel# 2 =>DA#
Calculate Flow-Rational Method
25-VrStorm
Qzs=CIA C= 0.30
1= 8.89 in/hr
Q25= 6.40 A= 2.40 ac
Channel Slope= 1.60
Channel Depth= 2.50
Channel Bottom Width= 4.00
Side Slopes— 3.00
Veloci = 3.62
Soil Type @ sandy loam Slopes=0-10%
Channel Lining
Shear Calculation
T=yds y= 62.4 Ibs
d—te 0.35 ft
T= 0.4368 Ibs/ft2 s= 0.016 ft/ft
Temporary=NAG S75BN
Permanent=Fescue(1.0 Ibs/ft2)

Permanent Channel# 3 => DA# 204
Calculate Flow- Rational Method
25-Yr Storm
Q25= CIA C= 0.35
1= 8.89 in/hr CA LC Tc
Q25= 6.53 A= 2.10 ac
Channel Slope= 1.00
Channel Depth= 1.00
Channel Bottom Width= 0.00
Side Slopes= 3.00
Velocity= 3.49
Soil Type @ sandy loam Slopes= 0-10%
Channel Lining
Shear Calculation
T=yds y= 62.4lbs
dwater 0.79 ft
T= 0.24648 Ibs/ftZ s= 0.01 ft/ft
Temporary= NAG S75BN
Permanent= Fescue (1.0 Ibs/ft2)

Channel Report
Hydraflow Express Extension for AutoCADO Civil 3DO 2009 by Autodesk, Inc. Thursday,Jul 20 2023
PC #1
Trapezoidal Highlighted
Bottom Width (ft) = 4.00 Depth (ft) = 1.80
Side Slopes (z:1) = 3.00, 3.00 Q (cfs) = 38.12
Total Depth (ft) = 2.50 Area (sqft) = 16.92
Invert Elev (ft) = 100.00 Velocity (ft/s) = 2.25
Slope (%) = 0.10 Wetted Perim (ft) = 15.38
N-Value = 0.022 Crit Depth, Yc (ft) = 1 .08
Top Width (ft) = 14.80
Calculations EGL (ft) = 1 .88
Compute by: Known Q
Known Q (cfs) = 38.12
Elev (ft) Section Depth (ft)
103.00 3.00
102.50 2.50
102.00 N71
2.00
101.50 1.50
101.00 1.00
100.50 0.50
100.00 0.00
99.50 -0.50
0 2 4 6 8 10 12 14 16 18 20 22 24
Reach (ft)

Channel Report
Hydraflow Express Extension for AutoCADO Civil 3DO 2009 by Autodesk, Inc. Thursday,Jul 20 2023
PC #2
Trapezoidal Highlighted
Bottom Width (ft) = 4.00 Depth (ft) = 0.35
Side Slopes (z:1) = 3.00, 3.00 Q (cfs) = 6.400
Total Depth (ft) = 2.50 Area (sqft) = 1.77
Invert Elev (ft) = 100.00 Velocity (ft/s) = 3.62
Slope (%) = 1.60 Wetted Perim (ft) = 6.21
N-Value = 0.022 Crit Depth, Yc (ft) = 0.39
Top Width (ft) = 6.10
Calculations EGL (ft) = 0.55
Compute by: Known Q
Known Q (cfs) = 6.40
Elev (ft) Section Depth (ft)
103.00 3.00
102.50 2.50
102.00 2.00
101.50 1.50
101.00 1.00
100.50 0 0.50
100.00 0.00
99.50 -0.50
0 2 4 6 8 10 12 14 16 18 20 22 24
Reach (ft)

Channel Report
Hydraflow Express Extension for AutoCADO Civil 3DO 2009 by Autodesk, Inc. Thursday,Jul 20 2023
PC #3
Triangular Highlighted
Side Slopes (z:1) = 3.00, 3.00 Depth (ft) = 0.79
Total Depth (ft) = 1.00 Q (cfs) = 6.530
Area (sqft) = 1.87
Invert Elev (ft) = 100.00 Velocity (ft/s) = 3.49
Slope (%) = 1.00 Wetted Perim (ft) = 5.00
N-Value = 0.022 Crit Depth, Yc (ft) = 0.79
Top Width (ft) = 4.74
Calculations EGL (ft) = 0.98
Compute by: Known Q
Known Q (cfs) = 6.53
Elev (ft) Section Depth (ft)
102.00 2.00
101.50 1.50
101.00 1.00
Is 7
100.50 0.50
100.00 0.00
99.50 -0.50
0 1 2 3 4 5 6 7 8
Reach (ft)

U.S. Department of Agriculture FL-ENG-21 B
Natural Resources Conservation Service 06/04
TR 55 Worksheet 3: Time of Concentration (Tc) or Travel Time (Tt)
Project: Carter Farms Subdivison Designed By: MTB Date:
Location: Hoke County, NC Checked By: MDA Date:
Check one: y/ Present Developed
Check one: V T, Tt through subarea DA#104
NOTES: Space for as many as two segments per flow type can be used for each worksheet. Include a map, schematic,
or description of flow segments.
Sheet Flow (Applicable to T, only) Segment ID 1
1. Surface description (Table 3-1) ................................................ GRASS
2. Manning's roughness coeff., n (Table 3-1) .............................. 0.04
3. Flow length, L (total L < 100 ft) .............................................. ft 100
4. Two-year 24-hour rainfall, P2.................................................. in 0.1
5. Land slope, s ....................................................................... ft/ft 0.050
6. Tt =0.007 (nL)0.8 Compute Tt.......................... hr 0.18 + = 0.18
P2 0.5 S0.4
Shallow Concetrated Flow Segment ID 2
7. Surface description (paved or unpaved) ................................... UNPAVED
8. Flow length, L ......................................................................... ft 557
9. Watercourse slope, s ........................................................... ft/ft 0.013
10. Average velocity, V(Figure 3-1) .......................................... ft/s 1.9
11. Tt = L Compute Tt ......................... hr 0.08 +
3600 V
Channel Flow Segment ID
12. Cross sectional flow area, a ............................................... ft2 0.0
13. Wetted perimeter, PW ......................................................... ft 0.0
14. Hydraulic radius, r= a Compute r .................................. ft
PW
15. Channel Slope, s ............................................................ ft/ft 0.000
16. Manning's Roughness Coeff., n ............................................ 0.00
17. V= 1.49 r2/3 s'/2 Compute V ...................... ft/s 0.0
n
18. Flow length, L ...................................................................... ft 0
19. Tt = L Compute Tt.................................... hr + _
3600 V
20. Watershed or subarea Tc or Tt (add Tt in steps 6, 11, and 19 ................................................................. hr 0.26
0.26= 15.6 mins

Chapter 3 Time of Concentration and Travel Time Technical Release 55
Urban Hydrology for Small Watersheds
Figure 3-1 Average velocities for estimating travel time for shallow-concentrated flow
.50
.20
.10
i2
d
a.
a
h .06
m
0 a
M .04 �-I
a
02
.01
.005
1 2 4 6 10 20
1.9
Average velocity(ftlsec)
3-2 (210-V1-TR-55,Second Ed.,dune 1986)

LEVEL SPREADER# 1
Calculate Flow- Rational Method
0.75 in/hr Design Storm
Q= CIA C= 0.40
1= 0.75 in/hr per MDC
Q= 3.00 A= 10.00 ac
Required Level Spreader L= 10 feet/1 cfs
Required Level Spreader L= 30.00 ft
Proposed Spreader L= 55.00 ft
Flow Depth 0.00 Flow discharged via inflitration in swale
10-Yr Storm
Q10= Outflow Treatment swale
Q10= 0.74 cfs
Flow Depth= 0.03 cfs
Proposed Stone Spreader Dims
Spreader L= 55 ft
Apron Width= 6 ft
Stone D= 12 in
Stone Dia= Class A

e
POI#01 Pre
Developmemt
SCM01
SCM 1 DA
01P
SCM #01
Subcat Reach on Link Routing Diagram for PC01
Prepared by Toshiba, Printed 9/21/2022
HydroCADO 10.00-20 s/n 07811 ©2017 HydroCAD Software Solutions LLC

Carter Farm Subdivision
PC01 Type/1 24-hr 10-Year Rainfall=5.52"
Prepared by Toshiba Printed 9/21/2022
HydroCADO 10.00-20 s/n 07811 ©2017 HydroCAD Software Solutions LLC Page 2
Summary for Subcatchment Pre POI #01: P0I#01 Pre Developmemt
Runoff = 2.96 cfs @ 12.02 hrs, Volume= 0.489 af, Depth= 0.32"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-72.00 hrs, dt= 0.05 hrs
Type II 24-hr 10-Year Rainfall=5.52"
Area (ac) CN Description
0.000 39 Woods
18.400 39 Grass
0.000 90 Pavement
0.000 90 Sidewalk
0.080 90 Buidling
18.480 39 Weighted Average
18.480 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment Pre POI #01: P0I#01 Pre Developmemt
Hydrograph
■Runoff
2.96cfs - - - - - - - - - - - - - - - - - - - - - -
3 Type III 24-hr
10-Yuar Rainfall'=5.52
RUnioffArdcl,18.480 Ac
2 tAnQ Qrl�•T•Y�0r� -�
w Runoff Qel'lpth=0.8�11
'--'�--'�--'�--
1
0
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72
Time (hours)

Carter Farm Subdivision
PC01 Type/1 24-hr 10-Year Rainfall=5.52"
Prepared by Toshiba Printed 9/21/2022
HydroCADO 10.00-20 s/n 07811 ©2017 HydroCAD Software Solutions LLC Page 3
Summary for Subcatchment SCM01: SCM 01 DA
Runoff = 16.66 cfs @ 11.99 hrs, Volume= 1.035 af, Depth= 0.67"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-72.00 hrs, dt= 0.05 hrs
Type II 24-hr 10-Year Rainfall=5.52"
Area (ac) CN Description
2.390 90 Impervious
16.010 39 Pervious
18.400 46 Weighted Average
18.400 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment SCM01: SCM 01 DA
Hydrograph
+ t t t ■Runoff
18 --I- 16.66 cfs -�-J-A-1-1-+-+-L-L-L- ----------J-J- -1-1-1-1-L- -L- --
17 -------- ----'--'- -+-+-+-+-+- ---------------'--'- ------- - -fir-
16 _ I_ + + + + r _ _i
15 ------'--' --'--'-------------------------71J�i��
14
I I I I I I I
12 -r---I--I --- - - -+-+-+-r-r-r-+-r-� r
Off OM I'
II--II--II--II--I -----1-1-+-+-+-r-r-r-r-r---I--I--I--I-7-r-,-7-7-7-}+-r-r-r-r-I--
10
0 9 -+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+-+-+-+-+ -��* �,
LL 8
+-+-+--- I�TJ� �111--
7 -------- ----- - -+-+-+-+-+- - - ---------- - - - - - -+-CN -
6 L-----'-- --'-J-J-L-1-+-+-+-L-r-L-L-L--------J-J-L- -1-1-1-r-L-L-L-I-
5
4
3
2
-------- ---- - - - - - - ------------------ - - - - - - -------
1 I I I I I I I I I I I I I I I I I I I I I I I I I I
0
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72
Time (hours)

Carter Farm Subdivision
PC01 Type/1 24-hr 10-Year Rainfall=5.52"
Prepared by Toshiba Printed 9/21/2022
HydroCADO 10.00-20 s/n 07811 ©2017 HydroCAD Software Solutions LLC Page 4
Summary for Pond 01 P: SCM #01
Inflow Area = 18.400 ac, 0.00% Impervious, Inflow Depth = 0.67" for 10-Year event
Inflow = 16.66 cfs @ 11.99 hrs, Volume= 1.035 of
Outflow = 1.43 cfs @ 13.95 hrs, Volume= 1.034 af, Atten= 91%, Lag= 117.5 min
Primary = 0.47 cfs @ 13.95 hrs, Volume= 0.894 of
Secondary = 0.96 cfs @ 13.95 hrs, Volume= 0.140 of
Routing by Stor-Ind method, Time Span= 1.00-72.00 hrs, dt= 0.05 hrs
Starting Elev= 197.00' Surf.Area= 3,765 sf Storage= 2,259 cf
Peak Elev= 199.03' @ 13.95 hrs Surf.Area= 15,748 sf Storage= 21,549 cf (19,290 cf above start)
Plug-Flow detention time= 591.6 min calculated for 0.983 of(95% of inflow)
Center-of-Mass det. time= 530.0 min ( 1,451.4 - 921.4 )
Volume Invert Avail.Storage Storage Description
#1 194.00' 21,549 cf Custom Stage Data (Prismatic)Listed below (Recalc)
Elevation Surf.Area Voids Inc.Store Cum.Store
(feet) (sq-ft) (%) (cubic-feet) (cubic-feet)
194.00 3,765 0.0 0 0
195.00 3,765 20.0 753 753
196.00 3,765 20.0 753 1,506
197.00 3,765 20.0 753 2,259
198.00 9,533 100.0 6,649 8,908
199.00 15,748 100.0 12,641 21,549
Device Routing Invert Outlet Devices
#1 Primary 197.00' 1.500 in/hr Exfiltration over Surface area above 197.00'
Conductivity to Groundwater Elevation = 190.00'
Excluded Surface area = 3,765 sf
#2 Secondary 199.00' 55.0' long x 10.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=0.47 cfs @ 13.95 hrs HW=199.03' (Free Discharge)
L1=Exfiltration ( Controls 0.47 cfs)
Secondary OutFlow Max=0.74 cfs @ 13.95 hrs HW=199.03' (Free Discharge)
L2=Broad-Crested Rectangular Weir(Weir Controls 0.74 cfs @ 0.44 fps)

Carter Farm Subdivision
PC01 Type/1 24-hr 10-Year Rainfall=5.52"
Prepared by Toshiba Printed 9/21/2022
HydroCADO 10.00-20 s/n 07811 ©2017 HydroCAD Software Solutions LLC Page 5
Pond 01 P: SCM #01
Hydrograph
16.66 CfS - ■Inflow
-r-r--r-r-rr-+-r--r-r--r-+-r--r-r--r-r-r--r-r- ■outflow
------ --------------------- �� ��{{" /�A r- ■Primary
h1fl
"= 10.4004 ■Secondary
18
17
16 � �
"'�J
14 -I-+-F -T- --+-T--T-r- T-+-T-I- -r--7-+- -I- -r-I- -T- -I- -r13
12
11 1-1-L -L-'--'-+-L_I_1-L_I_J-1-L_I_ - -
w i
10
---Y-r -r-I--I-Y-r-I-r-r-I-r-+-r-I-r-r--r-+-I---r-r-I-r-r----�-r-
3 9
lO 8 --I-+_T -T-�--+-T--+-T- -T-T--,-r-I-�-T-�-I-,-r----T-�---_r_
7 --i-i-i -i-i-i-i-i--i-i-i-i-i-i-- - ---i-i-i-- - ---i-i-i--i-i-
------------------------------------------------
5
-+ - ++ -+-+-1-+-+--+-+-++-+-+-++-+-++-+-+-++-+-+--+-+-
1.43 cfs
3
2 0.96 cfs
1
0
2 4 6 8 1012 14 1618 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72
Time (hours)

Carter Farm Subdivision
PC01 Type 11 24-hr 25-Year Rainfall=6.67"
Prepared by Toshiba Printed 9/21/2022
HydroCADO 10.00-20 s/n 07811 ©2017 HydroCAD Software Solutions LLC Page 6
Summary for Subcatchment Pre POI #01: P0I#01 Pre Developmemt
Runoff = 13.80 cfs @ 12.00 hrs, Volume= 1.007 af, Depth= 0.65"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-72.00 hrs, dt= 0.05 hrs
Type II 24-hr 25-Year Rainfall=6.67"
Area (ac) CN Description
0.000 39 Woods
18.400 39 Grass
0.000 90 Pavement
0.000 90 Sidewalk
0.080 90 Buidling
18.480 39 Weighted Average
18.480 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment Pre POI #01: P0I#01 Pre Developmemt
Hydrograph
r-r-i--i--i--i--i--i-y-y-t-t-+-t-r-r-r-r-r-r-i--i--i-y-y-y-�-rt-rt-t-r-r-r-r-r
15 1 ■Runoff
13.80cfs - - - - - - - - - - - - - - - - - -
14
r-r---i--i -----y-y-t-t-+-t-r-r-r-r-r-r------y-y-y T
13
------ ----
12 - 25-Yearl Rain 11=6.IV/ "--
r-r-i--i--i --i--i-y-y-t-t-+-t-r-r-r-r-r-r-i--i--i-y-y-y-�-rt-rt-t-r-r-r-r-r-
10
npff OM
9
Iu Hoff Deph= fi5
0 7 T
-------- -----------------------------------------Jd: 5.0-tnin
6 -------- ----- - - - - - - - - - ---------- - - - - - - -��� -
5
-----i- - -r-r-r-i-i---------------i-i-i-i- - -i-i-i
4
3
2
0
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72
Time (hours)

Carter Farm Subdivision
PC01 Type 11 24-hr 25-Year Rainfall=6.67"
Prepared by Toshiba Printed 9/21/2022
HydroCADO 10.00-20 s/n 07811 ©2017 HydroCAD Software Solutions LLC Page 7
Summary for Subcatchment SCM01: SCM 01 DA
Runoff = 33.74 cfs @ 11.98 hrs, Volume= 1.783 af, Depth= 1.16"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-72.00 hrs, dt= 0.05 hrs
Type II 24-hr 25-Year Rainfall=6.67"
Area (ac) CN Description
2.390 90 Impervious
16.010 39 Pervious
18.400 46 Weighted Average
18.400 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment SCM01: SCM 01 DA
Hydrograph
------------------------------------------
■Runoff
36 --- 33.74 I'1-I'1--I', -pI', -
34 1 IT R"�OZ4-hr-
----r-r-r-T-r-r-r-r-r-r-i-i------r-r-r-r
32
r-----i--i Y p c7
ai
28 r-r---i--i -----t-t-t-t-r-r-r-r-r-r-r-r ---t - r r-
26 FZwrio'ff /ark& 19.400 dG
r-r---i-- -
----t-t-t-t-r-r-r-r-r-r-r-I- i---i-.p--r-y-y-u4r rt-rtpp-t-r�r-r-r-r-
24
ff
V101
y 2220
-------- -----+-+-+-+-+-+-+-+-+-+----------+-+-+-+-+-+-+-+-+-+-+��-
p���^�{c 18 --'--'--'-- ----'-J- -1-L- -L-L-L-L-L----------J-J- - _1TC JO- 1n--
ML T
16 ------'-- --'--'- - -i-1-i-L-L-L- -+-------'--'- - - -1-1-1-i-L-r- -+-'--
14 j------'-- ------'- -'-'-'-'-'-'---------------'--'-'-'-
12
10
8
6
4
2
0
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72
Time (hours)

Carter Farm Subdivision
PC01 Type 11 24-hr 25-Year Rainfall=6.67"
Prepared by Toshiba Printed 9/21/2022
HydroCADO 10.00-20 s/n 07811 ©2017 HydroCAD Software Solutions LLC Page 8
Summary for Pond 01 P: SCM #01
Inflow Area = 18.400 ac, 0.00% Impervious, Inflow Depth = 1.16" for 25-Year event
Inflow = 33.74 cfs @ 11.98 hrs, Volume= 1.783 of
Outflow = 15.52 cfs @ 12.10 hrs, Volume= 1.783 af, Atten= 54%, Lag= 7.3 min
Primary = 0.48 cfs @ 12.10 hrs, Volume= 0.914 of
Secondary = 15.03 cfs @ 12.10 hrs, Volume= 0.869 of
Routing by Stor-Ind method, Time Span= 1.00-72.00 hrs, dt= 0.05 hrs
Starting Elev= 197.00' Surf.Area= 3,765 sf Storage= 2,259 cf
Peak Elev= 199.23' @ 12.11 hrs Surf.Area= 15,748 sf Storage= 21,549 cf (19,290 cf above start)
Plug-Flow detention time= 345.0 min calculated for 1.730 of(97% of inflow)
Center-of-Mass det. time= 316.1 min ( 1,213.0 - 896.8 )
Volume Invert Avail.Storage Storage Description
#1 194.00' 21,549 cf Custom Stage Data (Prismatic)Listed below (Recalc)
Elevation Surf.Area Voids Inc.Store Cum.Store
(feet) (sq-ft) (%) (cubic-feet) (cubic-feet)
194.00 3,765 0.0 0 0
195.00 3,765 20.0 753 753
196.00 3,765 20.0 753 1,506
197.00 3,765 20.0 753 2,259
198.00 9,533 100.0 6,649 8,908
199.00 15,748 100.0 12,641 21,549
Device Routing Invert Outlet Devices
#1 Primary 197.00' 1.500 in/hr Exfiltration over Surface area above 197.00'
Conductivity to Groundwater Elevation = 190.00'
Excluded Surface area = 3,765 sf
#2 Secondary 199.00' 55.0' long x 10.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=0.48 cfs @ 12.10 hrs HW=199.23' (Free Discharge)
L1=Exfiltration ( Controls 0.48 cfs)
Secondary OutFlow Max=14.54 cfs @ 12.10 hrs HW=199.22' (Free Discharge)
L2=Broad-Crested Rectangular Weir(Weir Controls 14.54 cfs @ 1.18 fps)

Carter Farm Subdivision
PC01 Type 1124-hr 25-Year Rainfall=6.67"
Prepared by Toshiba Printed 9/21/2022
HydroCADO 10.00-20 s/n 07811 ©2017 HydroCAD Software Solutions LLC Page 9
Pond 01 P: SCM #01
Hydrograph
33.74 CfS - - - ■inflow
- - -- - -- - - -- - -- - ---- - -- - ---- - - ■Outflow
■Primary
11i1V W /�1�i�� Iiv��l7V ��ii ■Secondary
---+-r -r----+-r--T-r--r-T-r--r-r--r-T----r-r--r-T----�-r-
36 �,
34 __� _� _
P'e' ev-1 -23 -
32 �p =
30 "'.7
e
28
26 --i-r-r -r-r-i-r-r-i-r-r-rr-+-r-i-r-r-i-r-+-r-i-r-r-i-r-r-r-i-r-r-
24
i 1
w 22 15.52 Cfs '�J- - -- - -��--�-�-
zo
3 1$
0 16 15103 CfS -r-r--r-r--r-r-rr-+-r--r-r--r-+-r--r-r--r-r-r--r-r-
14 -r-i -r-
12 - ---- - -- - -- - - -- - -- - ---- - -- - ---- - -
10
8
6
4
2
0
2 4 6 8 1012 14 1618 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72
Time (hours)

Carter Farm Subdivision
PC01 Type/1 24-hr 100-Year Rainfall=8.60"
Prepared by Toshiba Printed 9/21/2022
HydroCADO 10.00-20 s/n 07811 ©2017 HydroCAD Software Solutions LLC Page 10
Summary for Subcatchment Pre POI #01: POI#01 Pre Developmemt
Runoff = 40.53 cfs @ 11.98 hrs, Volume= 2.184 af, Depth= 1.42"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-72.00 hrs, dt= 0.05 hrs
Type II 24-hr 100-Year Rainfall=8.60"
Area (ac) CN Description
0.000 39 Woods
18.400 39 Grass
0.000 90 Pavement
0.000 90 Sidewalk
0.080 90 Buidling
18.480 39 Weighted Average
18.480 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment Pre POI #01: POI#01 Pre Developmemt
Hydrograph
-7
7
7
-1--1--1--1-+-+-t-+-+-+-r-r-r-r-r-r-1--1--1-+-+-+-+-+-+-+-r-r-r-r-r-
44 --i
42 ■Runoff
40.53 cfs -'- '- - - - - - - - - ----------�'-�'- - - - - - - - - -�'--
I I Tye �4-6-r -
40 -------- ----- - -+-+- -r-r-r- - ---------- - - -
1 1 1 1 1 I I I I I I I I I I I I I I I I I I I I I
38 r-r-1--1--1 --1--1-t-r-t-t-t-r-r-r-r-r-r-rA-/--/1--I�-/r-ry-rprwrt-1-t-r-rp-rc-nr-I--
36
34 ------'--' ----'-L- -L-L-L-L-L-L-L-r-'--'--'p-----L-L-L-1y�-,1�-1A-10-Lw-r-/fir-r-'--
32 ------i-- ----1-+-+-+-+-+-+-+-+-+-+---1-i� � i��i`iQ�1ET. F�it �--
30 m1 1 nI �I� I7-- AI
-----r-r-T-T-r-r-r-r_r_r-I - rlr� -ff ��f�4�'�rY��'.i_84
28 ------'-- ----'--'- - - - - - - -�-'--' of
-
w26 ------�-- -----r- - - - -r-r-r- - --------p-r- - - -'- - -r-r-�- -1--
2 24 r-1--r-1-- --1--1-r-T-T-T-r-r-r-r-r-r-r-r-1--1- 1 t#ii FF 1"r
3 22 --
--(1��---^�T--- ym-�-G--
l0 20
i I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I
18 --1--1--1-- --1--1-+-+-+-+-+-+-+-r-r-+-1--1--1--1--1-+-+-+-+-+-+-+- r-
16 ------�1-- --- - - -T-T-r-r-r-r-r-�r-��-��------ - - - -7-7-T- � -
14 ------'-- ------'- -'-'-'-'-'-'-'-----------'--'-'-'-'- -'-'-'-'-'---'--
12 --1--1--i-- --i--1- - - - - -r-r-r- - -------i--1- - - - - - - -r-r- - -i--
10 --1--1--1-- -----T-r-T-T-r-r-r-r-r-r----------T-r-r- -r-T-T-r-r-r-r-I--
6 -------- ----L- -L-L-L-L-L-L- - ----------L- - -L-L-L-L-L-L- - ---
4 r-r-1--1-- --+-+-+-+-+-+-r-r-r-r-r-r-1--1--1-+-+-+-+-+-+-+-r-r-r-r-r-
2
0
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72
Time (hours)

Carter Farm Subdivision
PC01 Type/1 24-hr 100-Year Rainfall=8.60"
Prepared by Toshiba Printed 9/21/2022
HydroCADO 10.00-20 s/n 07811 ©2017 HydroCAD Software Solutions LLC Page 11
Summary for Subcatchment SCM01: SCM 01 DA
Runoff = 68.81 cfs @ 11.97 hrs, Volume= 3.331 af, Depth= 2.17"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-72.00 hrs, dt= 0.05 hrs
Type II 24-hr 100-Year Rainfall=8.60"
Area (ac) CN Description
2.390 90 Impervious
16.010 39 Pervious
18.400 46 Weighted Average
18.400 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment SCM01: SCM 01 DA
Hydrograph
-
--------------,-r-+-+-r-r-r-r-r-r-r-I--I--I--I-r-r-r- -r-T-+-r-r-r-r-I--
75 ■Runoff
-I-r- - - -----,-,-1+--1r--Lr--Lr--Lr--Lr--Lr--1r-r-r-------------T- I-1-1I
-L-L- -L
70 68.8 1 L
P-p- - -
=� -
65
60 -' -' -' -' -''f0�f-Year Rain�f 11=8.60'�-
55 ----Ruhoff Arn&�1&400 jAc--
--
50 I N�® �
+-+-+-i-- -+-+-+-+-+-+-+-+-+-r-+-+-+ npff •T•Y
w 45
w ----
40 Runoff Depth=Z'�'
=-
LL 35
30
+-+-+ -- -+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+-+-+-+-+-+-+-CN=40-
20
15
10
tttt
0
L H....6....I....I....I....I....I....1. 1....I.... I....I....I....I....I....I....I....I....I........2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72
Time (hours)

Carter Farm Subdivision
PC01 Type/1 24-hr 100-Year Rainfall=8.60"
Prepared by Toshiba Printed 9/21/2022
HydroCADO 10.00-20 s/n 07811 ©2017 HydroCAD Software Solutions LLC Page 12
Summary for Pond 01 P: SCM #01
Inflow Area = 18.400 ac, 0.00% Impervious, Inflow Depth = 2.17" for 100-Year event
Inflow = 68.81 cfs @ 11.97 hrs, Volume= 3.331 of
Outflow = 81.44 cfs @ 11.99 hrs, Volume= 3.331 af, Atten= 0%, Lag= 1.3 min
Primary = 0.50 cfs @ 11.99 hrs, Volume= 0.921 of
Secondary = 80.94 cfs @ 11.99 hrs, Volume= 2.410 of
Routing by Stor-Ind method, Time Span= 1.00-72.00 hrs, dt= 0.05 hrs
Starting Elev= 197.00' Surf.Area= 3,765 sf Storage= 2,259 cf
Peak Elev= 199.67' @ 11.99 hrs Surf.Area= 15,748 sf Storage= 21,549 cf (19,290 cf above start)
Plug-Flow detention time= 184.6 min calculated for 3.279 of(98% of inflow)
Center-of-Mass det. time= 170.3 min ( 1,043.4 - 873.2 )
Volume Invert Avail.Storage Storage Description
#1 194.00' 21,549 cf Custom Stage Data (Prismatic)Listed below (Recalc)
Elevation Surf.Area Voids Inc.Store Cum.Store
(feet) (sq-ft) (%) (cubic-feet) (cubic-feet)
194.00 3,765 0.0 0 0
195.00 3,765 20.0 753 753
196.00 3,765 20.0 753 1,506
197.00 3,765 20.0 753 2,259
198.00 9,533 100.0 6,649 8,908
199.00 15,748 100.0 12,641 21,549
Device Routing Invert Outlet Devices
#1 Primary 197.00' 1.500 in/hr Exfiltration over Surface area above 197.00'
Conductivity to Groundwater Elevation = 190.00'
Excluded Surface area = 3,765 sf
#2 Secondary 199.00' 55.0' long x 10.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=0.50 cfs @ 11.99 hrs HW=199.63' (Free Discharge)
L1=Exfiltration ( Controls 0.50 cfs)
Secondary OutFlow Max=74.67 cfs @ 11.99 hrs HW=199.63' (Free Discharge)
L2=Broad-crested Rectangular Weir(Weir Controls 74.67 cfs @ 2.15 fps)

Carter Farm Subdivision
PC01 Type/1 24-hr 100-Year Rainfall=8.60"
Prepared by Toshiba Printed 9/21/2022
HydroCADO 10.00-20 s/n 07811 ©2017 HydroCAD Software Solutions LLC Page 13
Pond 01 P: SCM #01
Hydrograph
--1-1-L-1-1-1-1--1-1-L-1-1-L-1-J-1-L-i-�-�-�-J-+-�--�-�-L-1-J-1-1--1-1-L-
-+-+-++-+-+-++-+-++-+-+-++-+-++-+-+-++-+-++-+-+-++-+-++-+-+- ■Inflow
+--+-+-+--+-+--+-+-+--+-+--+-+-+--+-+--+-+-+--+-+- ■outflow
� � - �p� /�� � ■Primary
90 r-r--7-r-I- -r-r�-T-r-�� �rJYY i�W�����Eh �it��Fir- ■Secondary
85 80.94 cfs cfs T- -T-T T-T- -T- -+ - ,T-
80
- ---------------------------PekT;F� v-� �.� -
75L
70 -
65
60
55
u 50
3 45
LL 40 -1-1--1-i-L--1-L--J-1-L-'- -L--J-1-'--'- -L-'- -i----1-L-
35
30
-1-1--1-i-L-'-1-L-'-J-L-L-'-�-L-'-J-L-'--'-�-L-'-J-i-'--'-�-L-
25
20
15
10 S
5
0
2 4 6 8 1012 14 1618 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72
Time (hours)

Erosion Control

Sediment Basin# 1
Calculate Flow- Rational Method
10-Yr Storm 25-Yr Storm
Q10=CIA C= 0.30 Q25 = CIA C= 0.30
1= 7.98 1= 8.89
Q10= 30.88 A= 12.90 Q25 = 34.40 A= 12.90
2-Yr Storm
Q2= CIA C= 0.30
1= 6.18
Q2 = 23.92 A= 12.90
Calculate Required Surface Area
SA=Q10 x 435 sf/cfs Q10= 30.88
SA= 13433.93 ft2
Side Slopes= 3.00 :1
Pond Depth= 4.00 ft
Basin Dims (Per SA)
Top= 79.00 x 213.00 = 16827 ft2
Weir= 67.00 x 201.00 = 13467 ft2
Bottom = 43.00 x 177.00 = 7611 ft2
Volume Required
VR=Ax1800 cf/ac A= 12.90 ac
VR= 23220.00 ft3
Volume Proposed
VP=((Top Area + Bottom Area)/2)xD Top= 16827.00 sf
Bottom= 7611.00 sf
VP= 48876.00 ft3 D= 4.00 ft
Skimmer Sizing
Calculate Dewater Time

Qd=V/Td V= 23220.00 ft 3
Td= 5 3-5 days typ
Qd= 4644.00 cf/day
Calculate Orifice Diameter
D=sgrt((Qd/(2310sgrt(h))) Qd= 4644.00
h= 0.33
D= 1.87
Use 4 " Skimmer w/ 1.87 " Orifice
Principle Spillway Sizing
L=Q2/(cH1.5) L= ? ft
H= 1.50 ft
c= 3.10
L= 4.20 ft
Riser Sizing
C=pi X D C= 4.20 ft
pi= 3.14
D= 16.05 i n D= ? ft
Material= CMP
Use 24.00 "CMP Riser
Barrel Sizing
Q2= CA X sgrt(2gh) C= 0.60
A= ? sf
A= 2.12 Q2= 23.92 cfs
h= 5.50 ft
A=pi X r2 g= 32.20 ft/s
A= 19.71 in
Material= CMP
Use 18.00 "CMP Barrel
Size Riser/Barrel Base
Calculate Bouyance Force on Riser

Cross-sectional area
A=(pi x r2)x 2 r= 1.00
A= 6.28 sf
Riser Volume
V=A x L A= 6.28
L= 4.00
V= 25.12
Bouyance Force
FB=qV q= 62.40lbs
V= 25.12 ft3
FB= 1567.49lbs/cf
Concrete Base Sizing
(Concrete = 120 Ibs/cf)-(weight of water= 62.4 Ibs/cf) =57.6 Ibs/cf x 1.1 SAFETY FACTOR
Base Volume 29.93 cf
Base Dims= 5.47 ft x 5.47 ft x 1.00 ft
Weir Sizing
Per AutoCa d Hyd raflow Software
L= 10.00 ft
D= 2.00 ft
dwater 1.00 ft
Q25= 34.40 cfs
Velocity= 3.37 ft/s
Weir Lining
Shear Calculation
T=yds y= 62.4 Ibs
dwater 1 ft
T= 0.624 Ibs/ft2 s= 0.01 ft/ft
Required Liner= Class A Rip Rap
Proposed Liner= Class A Rip Rap

Temporary Diversion/Berm# 1 =>DA# EC401
Calculate Flow-Rational Method
25-Yr Storm
Q25=CIA C= 0.40
I*= 5.92 in/hr *IntensityperTc
Q25= 23.68 A= 10.00 ac
Channel Slope= 0.20
Channel Depth= 2.50
Bottom Width= 4.00
Side Slopes= 3.00
Velocity-- 3.42
Soil Type @ Loamy Sand Slopes=0-10%
Channel Linin¢
Shear Calculation
T=yds y= 62.4lbs
cl_,= 1.3 ft
T= 0.4056 Ibs/ft2 s= 0.005 ft/ft
Temporary= NAG S75BN
Permanent= NAG S75BN
Temporary Diversion/Berm# 2 =>DA# EC402
Calculate Flow-Rational Method
25-Yr Storm
Q25=CIA C= 0.40
I*= 6.38in/hr *Intensity per Tc
Q25= 4.59 A= 1.80 ac
Channel Slope= 0.00
Channel Depth= 2.00
Bottom Width= 4.00
Side Slopes= 3.00
Velocity-- 1.40
Soil Type @ Loamy Sand Slopes=0-10%
Channel Linin¢
Shear Calculation
T=yds y= 62.4lbs
cl—te,= 1.05 ft
T= 0.3276 Ibs/ft2 s= 0.005 ft/ft
Temporary= NAG S75BN
Permanent= NAG S75BN

Barrel Outlet Protection#1
New York Method 8.06.5 Manual
Diameter of Barrel = 18.00 " La= 8 ft
Velocity= 5.5 ft/s W= 6 ft
Zone= 1 Stone Diameter= Class a
Stone d= 12 in

Outlet Protection#100
New York Method 8.06.5 Manual
Q= 16.74 cfs La= 16 FT
Pipe Diameter 24 in W= 6 FT
Velocity= 17.3 ft/s d= 24 IN
Zone= 3 Stone Diameter= Class I
Outlet Protection#200
New York Method 8.06.5 Manual
Q= 5.3 cfs La= 6 FT
Pipe Diameter 15 in W= 4.5 FT
Velocity= 4.9 ft/s d= 12 IN
Zone= 1 Stone Diameter= Class A

APPENDIX B
Drainage Area Maps

i
� 1 \
� \ I
� 210 � � � 1 I DA PDyI
\ , I (ALL OTHER ORAINXG�AREAS INCLUDED)
18.4 AC r/— \
i
---
J
DA CBd202
0.4 AC r/—
POd2 o
2. ,
2.2 AC+�—
I / /
_ DA C81206 DA CBd201
0.6 AC+ 0.2 AC r/-
-—— _ 0.7 AC r/— DA CBd203
---- 0.2 AC+/—
-- _ DA CBg103 /
DA FESd204 / 0.25 AC+/—
--._----- 2.111 AC+/— / �pW
N.ANDERS DA DI®104 O /
(PRlygTE) 5` ;WW----3-2 AC+/----
Averette Engineering Co.,P.A. sEA� -IN eY: REVISIONS SCALE
MCK Na. DESCRIPTION DATE CARTER FARMS SUBDIVISION-PHASE 1
CHECKED BY:
L Sv EEenvc 71.2Add E.
C. D. AVERETTE CARTER ROAD 1" = 100'
LAND SURVEYING 712 E.Lake Ritlge ROOtl
PLANN/RG Raef.,d,NC 28376 PROJECT d: HOKE COUNTY,NORTH CAROLINA
PN<ne:[phone] 2020-11 SHEET NO.:
Fax:[phone] — NAN
License:C-0146 CPRTERFPRMS D&D DA2
DATE: DRAINAGE AREA MAP-INLET/PERMANENT CHANNELS
Established 1970 Web:www.averette—eng—T 1, 5/18/2022

\
210
DA 138#1
1 \
7---
DA EC/401ID.D AC
/
Averette Engineering Co.,P.A. ckL' Dom+�' REVISIONS
MTB ND. DESCRIPTION DATE
CHECKED Bf:
CARTER FARMS SUBDIVISION
L 'v En envc 71.2Add E.
C. D. AVERETTE CARTER ROAD 1'- 100
LAND SURVEYING 712 E.Lake Ritlge ROotl
PLANK/NG Raef.,d,NC 28376 PROJECT/: HOKE COUNTY,NORTH CAROLINA
PNane:[phone] 2020-11 SHEET NO.:
Fax:[phone]
License:C-0146 CMfERFORMS DJ D
DATE- DRAINAGE AREA MAP-EC DA1
Established 1970 Web:www.overette—eng.c2T 1, 5/18/2022

APPENDIX C
Soil Survey Map

Soil Map—Hoke County, North Carolina
in
v
674700 674800 674900 675000 675100 675200 675300 675400 675500 675600
34o 56'16"N I 34o 56'16"N
14
NJ
oA
JT
BaD
GdB N
Soil Map may not he valiel at this scale. OV
340 55'54"N -'I N 340 55'54"N
674700 67. 67. 67. 675100 675. 675300 67. 67. 675600
Map Scale:1:4,640 if printed on A landscape(11"x 8.5")sheet. a
N Meters
0 50 100 200 300
Feet
0 200 400 800 1200
Map projection:Web Mercator Conermordinates:WGS84 Edge tics:UTM Zone 17N WGS84
usoA Natural Resources Web Soil Survey 7/21/2021
Conservation Service National Cooperative Soil Survey Page 1 of 3

Soil Map—Hoke County, North Carolina
MAP LEGEND MAP INFORMATION
Area of Interest(A01) Spoil Area The soil surveys that comprise your AOI were mapped at
0 Area of Interest(AOI) Stony Spot 1:24,000.
p� Y
Soils Very Stony Spot Warning:Soil Map may not be valid at this scale.
0 Soil Map Unit Polygons
Wet spot Enlargement of maps beyond the scale of mapping can cause
,P Soil Map Unit Lines misunderstanding of the detail of mapping and accuracy of soil
Other line placement.The maps do not show the small areas of
Soil Map Unit Points Special Line Features contrasting soils that could have been shown at a more detailed
M�
Special Point Features scale.
Blowout Water Features
Streams and Canals Please rely on the bar scale on each map sheet for map
Borrow Pit measurements.
Transportation
Clay Spot _ Rails Source of Map: Natural Resources Conservation Service
Closed Depression Web Soil Survey URL:
.,o Interstate Highways Coordinate System: Web Mercator(EPSG:3857)
Gravel Pit US Routes
Maps from the Web Soil Survey are based on the Web Mercator
Gravelly Spot Major Roads projection,which preserves direction and shape but distorts
distance and area.A projection that preserves area,such as the
0 Landfill Local Roads Albers equal-area conic projection,should be used if more
A. Lava Flow Background accurate calculations of distance or area are required.
Marsh or swamp Aerial Photography This product is generated from the USDA-NRCS certified data as
of the version date(s)listed below.
Mine or Quarry
Soil Survey Area: Hoke County, North Carolina
Miscellaneous water Survey Area Data: Version 17,Jun 4,2020
Perennial Water Soil map units are labeled(as space allows)for map scales
Rock Outcrop 1:50,000 or larger.
Saline Spot Date(s)aerial images were photographed: Jun 15,2015—Dec 4,
2017
Sandy Spot
° The orthophoto or other base map on which the soil lines were
Severely Eroded Spot compiled and digitized probably differs from the background
imagery displayed on these maps.As a result,some minor
Sinkhole shifting of map unit boundaries may be evident.
Slide or Slip
o Sodic Spot
usoA Natural Resources Web Soil Survey 7/21/2021
Conservation Service National Cooperative Soil Survey Page 2 of 3

Soil Map—Hoke County, North Carolina
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
BaD Blaney loamy sand,8 to 15 14.4 13.1%
percent slopes
CaB Candor sand, 1 to 8 percent 0.6 0.6%
slopes
GdB Gilead loamy sand,2 to 8 2.6 2.4%
percent slopes
GoA Goldsboro loamy sand,0 to 2 8.4 7.6%
percent slopes, Southern
Coastal Plain
JT Johnston loam 10.2 9.3%
LaB Lakeland sand, 1 to 8 percent 9.8 8.9%
slopes
NoA Norfolk loamy sand,0 to 2 20.0 18.2%
percent slopes
WaB Wagram loamy sand,0 to 6 43.8 39.9%
percent slopes
Totals for Area of Interest 109.7 100.0%
USDA Natural Resources Web Soil Survey 7/21/2021
Conservation Service National Cooperative Soil Survey Page 3 of 3

APPENDIX D
FEMA Firm Map

�;- _.` --a � �' Fes• a`�, ure � ?��
��r I I COO' • D lI2EAS,
j. .L� ■y�'R J- �' �• �''' 4 ;N�+�* Creek
J
e
m 34°56'30"N
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a � 34°5601N
a 1
79°5'30"W 79°5'0"W 79°4'30^W
1980000 FEET

APPENDIX E
USGS MAP

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APPENDIX F
STORMWATER FORMS
SUPPLEMENT-EZ
OPERATION & MAINTENANCE AGGREEMENT
BMP SUPPLEMENT FORMS

Permit Number:
(to be provided by DWQ)
flF wAr�R
`=' r
NCDENR p
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
GRASSED SWALE SUPPLEMENT
This form must be filled out,printed and submitted.
The Required Items Checklist(Part III)must also be filled out,printed and submitted along with all of the required information.
I. PROJECT INFORMATION
Project name Carter Farms Subdivision-Phase 1
Contact name Averette Engineering Co.,P.A.
Phone number [phone]
Date May 18,2022
Drainage area number PD 1
II. DESIGN INFORMATION
Site Characteristics
Drainage area 801,504.00 ftz
Impervious area 104,108.00 ftZ
Percent impervious 13.0%%
Design rainfall depth 3.04 inch
Peak Flow Calculations
10-yr storm runoff depth 5.44 in
10-yr storm intensity 5.38 in/hr
Post-development 10-yr storm peak flow 34.60 ft/sec
Velocity
Velocity
Maximum non-erosive velocity(peak 10-year storm) 5.00 ft/sec
Soil characteristics(enter'Y'below)
Sand/silt(easily erodible) X
Clay mix(erosion resistant)
Grass Type(enter'Y'below)
Bermuda x
Tall fescue
Bah iag rass
Kentucky bluegrass
Grass-legume mixture
Swale type: Fill out one of the options below:
Option 1: Curb Outlet Swale: Y (Y or N)
Maximum velocity 3.60 OK
Side slopes 3.00 :1 Insufficient side slopes.Max is 5:1.
Swale length 858.00 ft OK
Option 2: Swale Seeking Pollutant Credit("For-Credit"Swale): (Y or N)
Maximum velocity for 10-yr storm ft/sec
Side slopes :1
Swale length ft
Form SW401-Grassed Swale-Rev.4 Parts I and 11.Project Design Summary,Page 1 of 2

Permit Number:
(to be provided by DWQ)
Swale Characteristics
Swale Shape: Enter an'Y'in the appropriate cell below:
Trapezoidal
Parabolic
V-shaped X
Width of the bottom of the Swale ft
Width of the top of the Swale ft
Additional Information
Is the Swale sized for all runoff from ultimate build-out? Y(Y or N) OK
Is the BMP located in a proposed drainage easement with a Y(Y or N) OK
recorded access easement to a public Right of Way(ROW)?
What is the distance from the bottom of the Swale to the SHWT? 12.00 ft OK
What is the ground level elevation? 201.00 fmsl
What is the elevation of the bottom of the Swale? 197.00 fmsl
What is the SHWT elevation? 185.00 fmsl
What is the longitudinal slope of the Swale? 0.10 % OK
What is the depth of freeboard? 0.67 ft OK
Form SW401-Grassed Swale-Rev.4 Parts I and 11.Project Design Summary,Page 2 of 2

Permit No:
(to be assigned 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.
Initials Pagel Plan
Sheet No.
MA C5 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),
-Swale dimensions(width, length,depth),
-Maintenance access,
-Proposed drainage easement and public right of way(ROW),
-Grass species,and
-Boundaries of drainage easement.
MA C7 2. Plan details(1"=50'or larger)for the grassed swale showing:
-Swale dimensions(width, length,depth),
-Maintenance access,
-Proposed drainage easement and public right of way(ROW),
-Design at ultimate build-out,
-Grass species,
-Off-site drainage(if applicable),and
-Boundaries of drainage easement.
MA C16 3. Section view of the grassed swale(1"=20'or larger)showing:
-Side slopes,
-Longitudinal slope,
-Freeboard
-Swale dimensions,and
-SHWT level(s)
MA 4. Supporting calculations(including maximum velocity calculations for applicable storms)
MA 5. A copy of the signed and notarized operation and maintenance(0&M)agreement.
MA 6. A copy of the deed restrictions(if required).
SW401-Grassed Swale-Rev.3 Part III, Page 1 of 1