SW4220901_Stormwater Narrative_20220921

STORMWATER
NARRATIVE AND DESIGN
CALCULATIONS
For:
Davidson Charter Academy
Davidson County, North Carolina
ADI Project No. 22-017
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Developer:
DCA Lexington Properties
500 Biesecker Road
Lexington, NC 27295
Prepared bv:
Allied Design, Inc.
4720 Kester Mill Road
Winston-Salem, NC 27103
[phone]
scausey@.allied-engsurv.com

STORMWATER NARRATIVE
DAVIDSON CHARTER ACADEMY
TABLE OF CONTENTS
A. Introduction
B. Methodology
C. Site Design and Assessment
D. Conclusion
Appendix
A. NOAA Rainfall Data (Hydraflow Rainfall Report)
B. Curve Number Summary
C. Wet Pond Calculations
D. 1-Year/24 Hour Frequency Design Storm Hydrographs
E. 100-Year Frequency Design Storm Hydrographs
F. Pond Report
G. Outlet Stabilization Calculations
H. Ditch Calculations
I. USDA Soils Report
J. National Wetlands Inventory Wetlands Delineation
K. ECS Geotechnical Engineering Report
Allied Design Inc. Project No.: 22-017 Page 1

STORMWATER NARRATIVE
DAVIDSON CHARTER ACADEMY
A. Introduction
The Davidson Charter Academy consists of a 30-acre parcel of property located
along Biesecker Road in Lexington, North Carolina. Phase 2 takes place on the
western portion of the site and proposes a new building addition, parking lots, paved
roads, and a soccer field. In accordance with the requirements of NCDEQ Post
Construction Stormwater program, the project will require a stormwater management
permit. However, the proposed permit will cover the entirety of the Davidson Charter
Academy project, including Phase 1, Phase 2, and up to an acre of future
impervious area.
Stormwater management permit approval will require design and construction of
permanent water quality measure to manage the runoff from all new impervious
coverage. The stormwater management plan for Davidson Charter Academy
utilizes a wet detention basin as the primary Stormwater Control Measures (SCM) to
meet NCDEQ's post construction stormwater management requirements. The wet
detention basin will be designed to treat the first 1-inch of runoff for quality
treatment.
B. Methodology
Reference for preparation of the stormwater management plan is made to the North
Carolina Division of Environmental Quality's "New Stormwater Design
Manual" (MDC's). City/County topographical maps, site surveys, and the
proposed site development plans were utilized to delineate the post -development
runoff patterns. The USDA Soils Survey was referenced and used to determine
the Runoff Curve Numbers (CN's).
The storm events modeled in this design are based on the SCS 24 Hour Storm
Distribution for the 1-year storm and the 6 Hour Storm Distribution for 100-year
design storm. The Intensity -Duration Frequency Curves were established using the
FHA Method. Precipitation frequency estimates were obtained from NOAA.
Allied Design Inc. Project No.: 22-017 Page 2

STORMWATER NARRATIVE
DAVIDSON CHARTER ACADEMY
Inflow hydrographs were derived from the SCS Unit Hydrograph Method and routed
through the proposed wet detention basin. The Storage Indication Method is used to
determine and verify design of the primary outlet structure. "Hydraflow Hydrographs",
2004 edition software was used to perform the routing calculations.
The wet detention basin design is based on capture of the first 1-inch of runoff. The
required surface area and volume is calculated based on the SA/DA method. Design
of forebays is included and are sized to provide 15-20% of the volume of the wet
detention basin.
The wet detention basin will utilize a precast concrete outlet structure to control the
post -developed runoff rates from the 1-year, 24-Hour storm event to a runoff rate that
minimizes hydrologic impacts to the receiving stream. The outlet structure is
modeled to assume 50% blockage of the overflow weir. The proposed detention is
designed to ensure the maximum storage elevation during the 100-year storm
remains at least 1 foot below the top of dam elevation.
C. Conclusion
This Stormwater Narrative concludes that the project is being developed in
accordance with the Wet Pond provisions of the MDC. As indicated by the
stormwater management plans and calculations included in this report, stormwater
quality and is being provided on -site in accordance with NCDEQ's stormwater
management requirements.
1. Stormwater Quality Management
The drainage area routed to the wet detention basin includes 26.16 acres with
approximately 7.46 acres being impervious. It should be noted that approximately
0.037 acres of the site are offsite and will be managed by the SCM.
The wet detention basin captures the first 1-inch of runoff from the post -developed
drainage areas and treats the flow in accordance with the requirements of the
Allied Design Inc. Project No.: 22-017 Page 3

STORMWATER NARRATIVE
DAVIDSON CHARTER ACADEMY
NCDEQ's Stormwater Design Manual. The routing hydrographs included in this
report also verify that the post -developed runoff for the 1-yr 24-hr water quality event
to a runoff rate that minimizes hydrologic impacts to the receiving stream. A
summary of the water quality management is provided as follows:
Summary of Water Quality Management
Management Aspects
Pond 1
Required
Provided
Water Quality Volume (cf)
27,824
29,385
Water Quality Elevation (ft)
757.7
757.8
Water Quality Surface Area (sf)
9,230
13,883
Allied Design Inc. Project No.: 22-017 Page 4

STORMWATER NARRATIVE
DAVIDSON CHARTER ACADEMY
Appendix
Allied Design Inc. Project No.: 22-017 Page 5

A.

Hydraflow Rainfall Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021
Return
Period
Intensity -Duration -Frequency Equation Coefficients (FHA)
(Yrs)
B
D
E
(N/A)
1
62.9479
13.1000
0.9022
--------
2
72.0400
13.2000
0.8883
--------
3
0.0000
0.0000
0.0000
--------
5
0.0000
0.0000
0.0000
--------
10
69.9702
12.5000
0.8066
--------
25
58.6655
11.0000
0.7384
--------
50
0.0000
0.0000
0.0000
--------
100
46.2960
9.0000
0.6519
--------
File name: dca intensity.IDF
Intensity = B / (Tc + D)^E
Thursday, 08 / 11 / 2022
Return
Period
Intensity Values (in/hr)
(Yrs)
5 min
10
15
20
25
30
35
40
45
50
55
60
1
4.62
3.70
3.10
2.68
2.36
2.11
1.91
1.75
1.61
1.50
1.40
1.31
2
5.47
4.41
3.71
3.21
2.83
2.54
2.30
2.11
1.95
1.81
1.69
1.59
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
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
10
6.95
5.68
4.83
4.22
3.76
3.40
3.11
2.87
2.66
2.49
2.34
2.21
25
7.57
6.20
5.29
4.65
4.16
3.78
3.47
3.22
3.00
2.82
2.66
2.52
50
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
100
8.29
6.79
5.83
5.16
4.65
4.25
3.93
3.66
3.44
3.24
3.08
2.93
Tc = time in minutes. Values may exceed 60.
name: W:\PROJECTS\22-017 Davidson Charter Academv\DESIGN\Stormwater\Hvdraflow Files\dca DreciD deDth.DCD
Storm
Rainfall Precipitation Table (in)
Distribution
1-yr
2-yr
3-yr
5-yr
10-yr
25-yr
50-yr
100-yr
SCS 24-hour
2.80
3.38
0.00
0.00
4.87
5.74
0.00
7.14
SCS 6-Hr
1.97
2.37
0.00
0.00
3.38
3.95
0.00
4.82
Huff -1st
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
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
0.00
0.00
0.00
0.00
0.00
0.00
0.00

CURVE NUMBER CALCULATIONS
POST DEVELOPMENT POI 1
TYPE OF AREA
SOIL GROUP
CN
CN SF
POI TOTAL AREA SF
%POI
%CN
WEIGHTED CN
ONSITE OPEN SPACE (FAIR)
B
68
606,273
1,139,349.00
53.21%
36.2
77
OFFSITE OPEN SPACE (FAIR)
B
69
208,378
18.29%
12.6
ONSITE GRAVEL
A
79
1,190
0.10%
0.1
ONSITE GRAVEL
B
85
10,811
0.95%
0.8
OFFSITE GRAVEL
B
85
1,617
0.14%
0.1
ONSITE IMPERVIOUS
A,B,C
98
1267,5201
23.48%1
23.0
FUTURE IMPERVIOUS
A,B,C
98
43,560
3.82%
1 3.7
IMPERVIOUS AREA
28%
ACRES
1 26.16

C.

Wet Pond Design Calculation Sheet
SA/DA Method
DAVIDSON CHARTER ACADEMY POND 1
August 12, 2022
Determine 1 inch Water Quality Volume (WQV)
Impervious area (IA) =
28%
Runoff Coefficient (Rv)=
0.302
Design Storm Depth (RD) =
1 in
Drainage Area (A) =
26.16 ac
Design Volume (Dv) =
28,678 cf
Determine Required Main Pool Surface Area
Percent Impervious Cover =
28%
Permanent Pool Average Depth =
5 ft
SA/DA =
0.81
Drainage Area =
26.16 ac
Required Surface Area =
0.21 ac
Required Surface Area =
9,230 sf
Confirm Pond Volume Provided (Main Pool Only)
Main Pool Elev. =
756.00
Vegetated Shelf Lower Elev. =
756.25
Vegetated Shelf Upper Elev. =
755.75
ELEV.
CONTOUR
AREA
INCREMENTAL
VOLUME
ACCUMULATED
VOLUME
(ft)
(sq ft)
(cf)
(cf)
756.00
13,883
0
0
756.25
15,342
3,653
3,653
757.00
16,473
11,931
15,584
758.00
18,029
17,251
32,835
759.00
19,643
18,836
51,671
760.00
21,314
20,479
72,149
761.00
1 25,375
j 23,345
95,494
762.00
1 27,441
1 26,408
121,902
Determine WQV Elevation Required
ELEVATION
ACCUMULATED
VOLUME
(ft)
(sq ft)
757.00
15,584
WQV ELEV
28,678
758.00
32,835
MIN. WQV ELEV.
757.76
Provided WQV Elevation
757.8
Provided WQV Volume (cf)
29,385

D.

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021
Thursday, 08 / 11 / 2022
Hyd. No. 4
post dev
Hydrograph type
= SCS Runoff
Peak discharge
= 38.45 cfs
Storm frequency
= 1 yrs
Time to peak
= 12.00 hrs
Time interval
= 2 min
Hyd. volume
= 88,773 cuft
Drainage area
= 26.160 ac
Curve number
= 77
Basin Slope
= 0.0 %
Hydraulic length
= 0 ft
Tc method
= User
Time of conc. (Tc)
= 8.00 min
Total precip.
= 2.80 in
Distribution
= Type II
Storm duration
= 24 hrs
Shape factor
= 484
Q (Cfs)
40.00
30.00
20.00
10.00
0.00 ' ' 1
0 2 4
— Hyd No. 4
post dev
Hyd. No. 4 -- 1 Year
6 8 10 12 14 16 18 20 22 24
Q (Cfs)
40.00
30.00
20.00
10.00
'- 0.00
26
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021
Thursday, 08 / 11 / 2022
Hyd. No. 6
pond 1
Hydrograph type
= Reservoir
Peak discharge
= 9.466 cfs
Storm frequency
= 1 yrs
Time to peak
= 12.17 hrs
Time interval
= 2 min
Hyd. volume
= 88,371 cuft
Inflow hyd. No.
= 4 - post dev
Max. Elevation
= 758.06 ft
Reservoir name
= pond 1
Max. Storage
= 33,929 cuft
Storage Indication method used
Q (cfs)
40.00
30.00
20.00
10.00
0.00 1 ' —
0 4
— Hyd No. 6
pond 1
Hyd. No. 6 -- 1 Year
8 12 16 20
Hyd No. 4
24 28 32 36 40 44
Total storage used = 33,929 cuft
Q (cfs)
40.00
30.00
20.00
10.00
—' 0.00
48
Time (hrs)

E.

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021
Thursday, 08 / 11 / 2022
Hyd. No. 3
post dev
Hydrograph type
= SCS Runoff
Peak discharge
= 56.81 cfs
Storm frequency
= 100 yrs
Time to peak
= 2.43 hrs
Time interval
= 2 min
Hyd. volume
= 234,848 cuft
Drainage area
= 26.160 ac
Curve number
= 77
Basin Slope
= 0.0 %
Hydraulic length
= 0 ft
Tc method
= User
Time of conc. (Tc)
= 8.00 min
Total precip.
= 4.82 in
Distribution
= SCS 6-Hr
Storm duration
= 6.00 hrs
Shape factor
= 484
Q (Cfs)
60.00
50.00
40.00
30.00
20.00
10.00
0.00
0.0 1.0
— Hyd No. 3
post dev
Hyd. No. 3 -- 100 Year
2.0 3.0 4.0 5.0 6.0
Q (Cfs)
60.00
50.00
40.00
30.00
20.00
10.00
1 0.00
7.0
Time (hrs)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021
Friday, 08 / 12 / 2022
Hyd. No. 5
pond 1
Hydrograph type
= Reservoir
Peak discharge
= 32.34 cfs
Storm frequency
= 100 yrs
Time to peak
= 2.63 hrs
Time interval
- 2 min
Hyd. volume
= 234,551 cuft
Inflow hyd. No.
- 3 - post dev
Max. Elevation
= 759.41 ft
Reservoir name
= pond 1
Max. Storage
= 59,971 cuft
Storage Indication method used.
Q (cfs)
60.00
50.00
40.00
30.00
20.00
10.00
am
NEW111XV
pond 1
Hyd. No. 5 -- 100 Year
2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Hyd No. 5 — Hyd No. 3 Total storage used = 59,971 cuft
Q (cfs)
60.00
50.00
40.00
30.00
20.00
10.00
--' 0.00
18.0
Time (hrs)

F.

Pond Report 4
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021
Tuesday, 08 / 23 / 2022
Pond No. 1 -
pond 1
Pond Data
Contours -User-defined contour areas.
Conic method used for volume calculation. Begining Elevation = 756.00 ft
Stage / Storage Table
Stage (ft)
Elevation (ft)
Contour area (sgft)
Incr. Storage (cult)
Total storage (cult)
0.00
756.00
13,883
0
0
0.25
756.25
15,342
3,651
3,651
1.00
757.00
16,473
11,927
15,578
2.00
758.00
18,029
17,243
32,822
3.00
759.00
19,643
18,828
51,650
4.00
760.00
21,314
20,471
72,121
6.00
762.00
27,441
48,621
120,742
Culvert / Orifice Structures
Weir Structures
[A]
[B]
[C]
[PrfRsr]
[A] [B]
[C]
[D]
Rise (in)
= 24.00
4.00
0.00
0.00
Crest Len (ft)
= 20.00 Inactive
0.00
0.00
Span (in)
= 24.00
4.00
0.00
0.00
Crest El. (ft)
= 757.80 0.00
0.00
0.00
No. Barrels
= 1
1
0
0
Weir Coeff.
= 3.33 3.33
3.33
3.33
Invert El. (ft)
= 753.80
756.00
0.00
0.00
Weir Type
= 1 Broad
---
---
Length (ft)
= 64.00
0.50
0.00
0.00
Multi -Stage
= Yes No
No
No
Slope (%)
= 1.25
0.01
0.00
n/a
N-Value
= .013
.013
.013
n/a
Orifice Coeff.
= 0.60
0.60
0.60
0.60
Exfil.(in/hr)
= 0.000 (by Wet area)
Multi -Stage
= n/a
Yes
No
No
TW Elev. (ft)
= 0.00
Stage (ft)
6.00
6'x11IH
4.00
3.00
PAIIH
m
Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s)
4.00 8.00 12.00
Total Q
Stage / Discharge
Elev (ft)
762.00
760.00
759.00
757.00
' ' ' ' ' ' ' ' 756.00
16.00 20.00 24.00 28.00 32.00 36.00 40.00 44.00
Discharge (cfs)

G.

Allied Design, Inc.
CIVIL ENGINEERING ❖ LAND SURVEYING
4720 Kester Mill Road
Winston-Salem, North Carolina 27103
Ph. 336.765.2377 •a Fax [phone]
Outlet Stabilization
In .__TT
PROJECT NAME Davidson Charter School
Outlet Stabilization
PROJECT NO. 22-017
BY WAB
CHECKED BY SMC
SHEET OF
DATE 3-May-22
REV 3-May-22
Z
s b lu 2u bu 100 200 500 1000
Discharge (0/sec)
Curves may not be extrapolated.
Figure 8.06a Design of outlet protection protection from a round pipe flowing full, minimum tailwater condition (Tw < 0.5 diameter).
Outlet
Pipe
Diameter
Discharge
d50
La
W
dmax
apron
thickness
NCDOT
riprap
(in)
(cfs)
(ft)
(ft)
(ft)
(ft)
(ft)
Class
100
15
2.68
0.20
8.0
9.3
0.3
0.5
A
200
1 15
8.64
0.35
10.0
11.3
1 0.5
0.8
B
300
36
20.89
0.60
20.0
23.0
0.9
1.4
B
400
24
15.76
0.40
13.0
15.0
0.6
0.9
B
500
15
3.77
0.20
8.0
9.3
0.3
0.5
A
600
24
1 9.47
1 0.50
1 10.0
1 12.0
0.8
1 1.1
1 B
TAKEN FROM THE NORTH CAROLINA EROSION AND SEDIMENT CONTROL

H.

DITCH SCHEDULE (25 YEAR STORM DESIGN)
DAVIDSON CHARTER SCHOOL
DAVIDSON COUNTY, NORTH CAROLINA
August 12, 2022
z
U
=~
0
w
Q
w
<
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(AC)
w
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_U-
w
J
w w
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Z
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Q
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w
O
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(IN/HR)
W
z
z
-
w
CD
0-1
=
U
o
(CFS)
a
O
j
U
~
0
(FT/FT)
=
0
O
O
0o
(FT)
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�
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w
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("X" : 1)
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(FPS)
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w
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Z
J
Z
�
w
Q
aW
-1z
a
W
1
0.60
0.50
5
7.60
2.28
9.00%
0
3
0.40
4.79
S75
D
2
0.60
0.50
5
7.60
2.28
4.50%
3
3
0.23
2.63
S75
D
3
0.38
0.50
5
7.60
1.44
6.00%
3
3
0.39
3.22
S75
D
4
0.50
0.50
5
7.60
1.90
1.25%
0
3
0.67
1.41
S75
D
5
0.23
0.50
5
7.60
0.87
1.25%
0
3
0.52
1.08
S75
D
6
2.07
0.50
5
7.60
7.87
3.70%
10
3
0.26
2.80
S75
D
7
13.18
0.50
5
7.60
50.08
5.00%
15
3
0.40
5.88
S75
D
8
9.11
0.50
5
7.60
34.62
3.00%
10
3
0.58
5.05
S75
D
9
2.38
0.50
5
7.60
9.04
6.25%
6
3
0.28
4.65
S75
D
10
2.31
0.50
5
7.60
8.78
11.40%
5
3
0.23
6.68
RIP RAP
D
11
13.16
0.50
5
7.60
50.01
3.00%
5
3
0.76
9.05
RIP RAP
D

NORTH
AMERICAN
GREEN
CHANNEL ANALYSIS
> > > Ditch #1
Name
Ditch #1
Discharge
2.28
Channel Slope
0.09
Channel Bottom Width
0
Left Side Slope
3
Right Side Slope
3
Low Flow Liner
Retardence Class
D 2-6 in
Vegetation Type
Mix (Sod and Bunch)
Vegetation Density
Fair 50-64%
Soil Type
Clay Loam (CL)
Unreinforced Vegetation
North American Green
5401 St. Wendel -Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
> Fax [phone]
www.nagreen.com
ECMDS v7.0
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
Unreinforced Straight 2.28 cfs 4.79 ft/s 0.4 ft 0.031 4 Ibs/ft2 2.23 Ibs/ft2 1.79 STABLE
Vegetation
Underlying Straight 2.28 cfs 4.79 ft/s 0.4 ft 0.031 1.46 Ibs/ft2 1.06 Ibs/ft2 1.38 STABLE
Substrate

NORTH
AMERICAN
GREEN
CHANNEL ANALYSIS
> > > Ditch #2
Name
Ditch #2
Discharge
2.28
Channel Slope
0.045
Channel Bottom Width
3
Left Side Slope
3
Right Side Slope
3
Low Flow Liner
Retardence Class
D 2-6 in
Vegetation Type
Mix (Sod and Bunch)
Vegetation Density
Fair 50-64%
Soil Type
Clay Loam (CL)
Unreinforced Vegetation
North American Green
5401 St. Wendel -Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
> Fax [phone]
www.nagreen.com
ECMDS v7.0
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
Jnreinforced Straight 2.28 cfs 2.63 ft/s 0.23 ft 0.04 4 Ibs/ft2 0.66 Ibs/ft2 6.1 STABLE
Vegetation
Underlying Straight 2.28 cfs 2.63 ft/s 0.23 ft 0.04 2.5 Ibs/ft2 0.54 Ibs/ft2 4.61 STABLE
Substrate

NORTH
AMERICAN
GREEN
CHANNEL ANALYSIS
> > > Ditch #3
Name
Ditch #3
Discharge
1.44
Channel Slope
0.06
Channel Bottom Width
0
Left Side Slope
3
Right Side Slope
3
Low Flow Liner
Retardence Class
D 2-6 in
Vegetation Type
Mix (Sod and Bunch)
Vegetation Density
Fair 50-64%
Soil Type
Clay Loam (CL)
Unreinforced Vegetation
North American Green
5401 St. Wendel -Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
> Fax [phone]
www.nagreen.com
ECMDS v7.0
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
Unreinforced Straight
Vegetation
Underlying Straight
Substrate
1.44 cfs 3.22 ft/s 0.39 ft 0.036
1.44 cfs 3.22 ft/s 0.39 ft 0.036
4lbs/ft2 1.44lbs/ft2 2.77 STABLE
2.07lbs/ft2 0.69lbs/ft2 3.03 STABLE

NORTH
AMERICAN
GREEN
CHANNEL ANALYSIS
> > > Ditch #4
Name
Ditch #4
Discharge
1.9
Channel Slope
0.0125
Channel Bottom Width
0
Left Side Slope
3
Right Side Slope
3
Low Flow Liner
Retardence Class
D 2-6 in
Vegetation Type
Mix (Sod and Bunch)
Vegetation Density
Fair 50-64%
Soil Type
Clay Loam (CL)
Unreinforced Vegetation
North American Green
5401 St. Wendel -Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
> Fax [phone]
www.nagreen.com
ECMDS v7.0
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
Jnreinforced Straight 1.9 cfs 1.41 ft/s 0.67 ft 0.055 4 Ibs/ft2 0.52 Ibs/ft2 7.66 STABLE
Vegetation
Underlying Straight 1.9 cfs 1.41 ft/s 0.67 ft 0.055 4 Ibs/ft2 0.25 Ibs/ft2 16.15 STABLE
Substrate

NORTH
AMERICAN
GREEN
CHANNEL ANALYSIS
> > > Ditch #5
Name
Ditch #5
Discharge
0.87
Channel Slope
0.0125
Channel Bottom Width
0
Left Side Slope
3
Right Side Slope
3
Low Flow Liner
Retardence Class
D 2-6 in
Vegetation Type
Mix (Sod and Bunch)
Vegetation Density
Fair 50-64%
Soil Type
Clay Loam (CL)
Unreinforced Vegetation
North American Green
5401 St. Wendel -Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
> Fax [phone]
www.nagreen.com
ECMDS v7.0
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
Jnreinforced Straight 0.87 cfs 1.08 ft/s 0.52 ft 0.061 4 Ibs/ft2 0.4 Ibs/ft2 9.89 STABLE
Vegetation
Underlying Straight 0.87 cfs 1.08 ft/s 0.52 ft 0.061 4 Ibs/ft2 0.19 Ibs/ft2 20.85 STABLE
Substrate

NORTH
AMERICAN
GREEN
CHANNEL ANALYSIS
> > > Ditch #6
Name
Ditch #6
Discharge
7.87
Channel Slope
0.037
Channel Bottom Width
10
Left Side Slope
3
Right Side Slope
3
Low Flow Liner
Retardence Class
D 2-6 in
Vegetation Type
Mix (Sod and Bunch)
Vegetation Density
Fair 50-64%
Soil Type
Clay Loam (CL)
Unreinforced Vegetation
North American Green
5401 St. Wendel -Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
> Fax [phone]
www.nagreen.com
ECMDS v7.0
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
Unreinforced Straight 7.87 cfs 2.8 ft/s 0.26 ft 0.04 4 Ibs/ft2 0.6 Ibs/ft2 6.65 STABLE
Vegetation
Underlying Straight 7.87 cfs 2.8 ft/s 0.26 ft 0.04 2.45 Ibs/ft2 0.56 Ibs/ft2 4.39 STABLE
Substrate

NORTH
AMERICAN
GREEN
CHANNEL ANALYSIS
> > > Ditch #7
Name
Ditch #7
Discharge
50.08
Channel Slope
0.05
Channel Bottom Width
20
Left Side Slope
3
Right Side Slope
3
Low Flow Liner
Retardence Class
D 2-6 in
Vegetation Type
Mix (Sod and Bunch)
Vegetation Density
Fair 50-64%
Soil Type
Clay Loam (CL)
Unreinforced Vegetation
North American Green
5401 St. Wendel -Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
> Fax [phone]
www.nagreen.com
ECMDS v7.0
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
Unreinforced Straight 50.08 cfs 5.88 ft/s 0.4 ft 0.029 4 Ibs/ft2 1.24 Ibs/ft2 3.22 STABLE
Vegetation
Underlying Straight 50.08 cfs 5.88 ft/s 0.4 ft 0.029 1.35 Ibs/ft2 1.17 Ibs/ft2 1.15 STABLE
Substrate

NORTH
AMERICAN
GREEN
CHANNEL ANALYSIS
> > > Ditch #8
Name
Ditch #8
Discharge
34.61
Channel Slope
0.03
Channel Bottom Width
10
Left Side Slope
3
Right Side Slope
3
Low Flow Liner
Retardence Class
D 2-6 in
Vegetation Type
Mix (Sod and Bunch)
Vegetation Density
Fair 50-64%
Soil Type
Clay Loam (CL)
Unreinforced Vegetation
North American Green
5401 St. Wendel -Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
> Fax [phone]
www.nagreen.com
ECMDS v7.0
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
Unreinforced Straight
Vegetation
Underlying Straight
Substrate
34.61 cfs 5.05 ft/s 0.58 ft 0.032
34.61 cfs 5.05 ft/s 0.58 ft 0.032
4lbs/ft2 1.09lbs/ft2 3.67 STABLE
1.61lbs/ft2 0.94lbs/ft2 1.72 STABLE

NORTH
AMERICAN
GREEN
CHANNEL ANALYSIS
> > > Ditch #9
Name
Ditch #9
Discharge
9.04
Channel Slope
0.0625
Channel Bottom Width
6
Left Side Slope
3
Right Side Slope
3
Low Flow Liner
Retardence Class
D 2-6 in
Vegetation Type
Mix (Sod and Bunch)
Vegetation Density
Fair 50-64%
Soil Type
Clay Loam (CL)
Unreinforced Vegetation
North American Green
5401 St. Wendel -Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
> Fax [phone]
www.nagreen.com
ECMDS v7.0
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
Unreinforced Straight
Vegetation
Underlying Straight
Substrate
9.04 cfs 4.65 ft/s 0.28 ft 0.032
9.04 cfs 4.65 ft/s 0.28 ft 0.032
4lbs/ft2 1.11lbs/ft2 3.62 STABLE
1.57lbs/ft2 0.97lbs/ft2 1.61 STABLE

NORTH
AMERICAN
GREEN
CHANNEL ANALYSIS
> > > Ditch #10
Name
Ditch #10
Discharge
8.78
Channel Slope
0.114
Channel Bottom Width
5
Left Side Slope
3
Right Side Slope
3
Low Flow Liner
Retardence Class
D 2-6 in
Vegetation Type
Mix (Sod and Bunch)
Vegetation Density
Fair 50-64%
Soil Type
Clay Loam (CL)
Rock Riprap
North American Green
5401 St. Wendel -Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v7.0
Phase Reach Discharge Velocity Normal Mannings N Permissible Calculated Safety Remarks Staple
Depth Shear Stress Shear Stress Factor Patters
Rock Riprap Straight 8.78 cfs 6.68 ft/s 0.23 ft 0.026 2 Ibs/ft2 1.45 Ibs/ft2 1.38 STABLE --
Unvegetated

NORTH
AMERICAN
GREEN
CHANNEL ANALYSIS
> > > Ditch #11
Name
Ditch #11
Discharge
50.01
Channel Slope
0.054
Channel Bottom Width
5
Left Side Slope
3
Right Side Slope
3
Low Flow Liner
Retardence Class
D 2-6 in
Vegetation Type
Mix (Sod and Bunch)
Vegetation Density
Fair 50-64%
Soil Type
Clay Loam (CL)
Rock Riprap
North American Green
5401 St. Wendel -Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v7.0
Phase Reach Discharge Velocity Normal Mannings N Permissible Calculated Safety Remarks Staple
Depth Shear Stress Shear Stress Factor Patters
Rock Riprap Straight 50.01 cfs 9.05 ft/s 0.76 ft 0.026 2 Ibs/ft2 1.9 Ibs/ft2 1.05 STABLE --
Unvegetated

IN

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Hydrologic Soil Group —Davidson County, North Carolina
MAP LEGEND
Area of Interest (AOI)
0
Area of Interest (AOI)
Soils
Soil Rating
Polygons
0
A
0
A/D
0
B
0
B/D
C
0
C/D
0
D
0
Not rated or not available
Soil Rating
Lines
r 0
A
r 0
A/D
B
B/D
N 0
C
r 0
C/D
r 0
D
r 0
Not rated or not available
Soil Rating
Points
0
A
0
A/D
0
B
0
B/D
❑ C
0 C/D
0 D
❑ Not rated or not available
Water Features
Streams and Canals
Transportation
— Rails
­0 Interstate Highways
US Routes
Major Roads
Local Roads
Background
D6 Aerial Photography
MAP INFORMATION
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Davidson County, North Carolina
Survey Area Data: Version 23, Jan 21, 2022
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Oct 17, 2020—Nov 3,
2020
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
usoA Natural Resources Web Soil Survey 7/25/2022
Conservation Service National Cooperative Soil Survey Page 2 of 4

Hydrologic Soil Group —Davidson County, North Carolina
Hydrologic Soil Group
Map unit symbol
Map unit name
Rating
Acres in AOI
Percent of AOI
CcB
Cecil sandy loam, 2 to 8
percent slopes
B
40.9
58.0%
CcD
Cecil sandy loam, 8 to
15 percent slopes
A
2.7
3.9%
CeD2
Cecil clay loam, 8 to 15
percent slopes,
moderately eroded
B
25.0
35.5%
PnE
Poindexter-Wynott
complex, 15 to 25
percent slopes
C
1.0
1.4%
W
Water
0.8
1.2%
Totals for Area of Interest
70.5
100.0%
USDA Natural Resources Web Soil Survey 7/25/2022
Conservation Service National Cooperative Soil Survey Page 3 of 4

Hydrologic Soil Group —Davidson County, North Carolina
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive
precipitation from long -duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when
thoroughly wet. These consist mainly of deep, well drained to excessively
drained sands or gravelly sands. These soils have a high rate of water
transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well
drained soils that have moderately fine texture to moderately coarse texture.
These soils have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of
water transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink -swell
potential, soils that have a high water table, soils that have a claypan or clay
layer at or near the surface, and soils that are shallow over nearly impervious
material. These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in
their natural condition are in group D are assigned to dual classes.
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff.- None Specified
Tie -break Rule: Higher
USDA Natural Resources Web Soil Survey 7/25/2022
Conservation Service National Cooperative Soil Survey Page 4 of 4

J.

U.S. Fish and Wildlife Service
National Wetlands Inventor
August 31, 2022
Wetlands
U Estuarine and Marine Deepwater .
Estuarine and Marine Wetland ❑
Wetlands Delineation for Davidson Charter
This map is for general reference only. The US Fish and Wildlife
Service is not responsible for the accuracy or currentness of the
base data shown on this map. All wetlands related data should
Freshwater Emergent Wetland Lake be used in accordance with the layer metadata found on the
Wetlands Mapper web site.
Freshwater Forested/Shrub Wetland ❑ Other
Freshwater Pond ❑ Riverine
National Wetlands Inventory (NW)
This page was produced by the NW mapper

K.