SW6211203_Design Calculations_20220310

Sform wofer Monogement Reporf
Mo rc h 10, 2022
McCain Gas Station
NC Hwy 211
Hoke County, NC
Prepared for:
Double D Engineering, PLLC
150 S. Page Street
Southern Pines, NC 28387
910-684-8646
Prepared by:
Bowman
4006 Barrett Drive, Suite 104
Raleigh, NC 27609
[phone]
FIRM# F-1445
CA
SEAL
❑51571 =

TABLE OF CONTENTS
OVERVIEW
FIGURES
SOILS SURVEY & SOIL INFORMATION
USGS TOPOGRAPHIC MAP
FEMA FIRM MAP
WATER SURFACE CLASSIFICATIONS
HUC
NOAA POINT PRECIPITATION FREOUENCY ESTIMATES
SHWT REPORT
WATER QUANTITY -INFILTRATION BASIN
DRAINAGE AREA MAP
DESIGN SUPPLEMENT
CN VALUES
PRE -DEVELOPMENT HYDROGRAPHS
POST -DEVELOPMENT HYDROGRAPHS
TIME VS. VOLUME (STORAGE)
TIME VS. ELEVATION (STAGE)
ELEVATION -VOLUME -FLOW SUMMARY
SCM SUMMARY
TIME OF CONCENTRATION

OVERVIEW
This report contains the storm water management overview for the proposed gas station
site on NC Hwy 211 in Hoke County. The project site is currently a gas station. The
proposed site consists of 5.096 acres and approximately 3.69 acres will be disturbed as
part of this project for the construction of the site improvements.
The proposed site is located in Flood Zone `X' as shown on FEMA FIRM Panel 3710848600J
with an effective date of 10/17/06. Flood zones are subject to change by FEMA.
There are no existing stream or wetland features on the proposed property.
The drainage area consists of 14,822sf (0.34 ac) off —site area that will be considered
100% BUA. The drainage area also consists of 10,993sf of existing impervious area that
will be future NCDOT roadway. The proposed storm water management facility (infiltration
basin) outlined in this report has been designed for post —development peak attenuation to
treat the impervious areas of the development. The Infiltration Basin is designed to capture
a drainage area of 3.43 ac with an impervious area of 2.10 ac. The balance of the site
is open space and will by—pass the proposed SCM, The SCM are designed to treat a 1.0"
storm event.
Impervious Area Summary — Infiltration Basin
Parking
56,714
1.30
Sidewalk
1910
0.04
Building
7,000
0.16
Future Impervious NCDOT
10,993
0.25
Off -Site
14,822
0.34
Total IA to Pond
91,439
2.10
The County Soils Survey indicates that Blaney Loamy Sand soils are present on the site.

FIGURES

3V Y4S N
35' Y39'N
Hydrologic Soil Group —Hoke County, North Carolina
3 — 3
Map Scale: 1:1,480If rated al A pd patrat (8.5" x 11') dxct. Meters
N 0 2D 40 80 12'D
� Fed
0 50 100 20D 300
Map pro]edbn: Web Mmallor Oxnercoordrotes: WGS84 Edgetl6: UTM Zane 17N WGS84
35° Y 48' N
35° Y 39' N
l IND,•, Natural Resources Web Soil Survey 10/14/2021
Conservation Service National Cooperative Soil Survey Page 1 of 4

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Hydrologic Soil Group —Hoke County, North Carolina
Hydrologic Soil Group
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
BaB
Blaney loamy sand, 2 to C
8 percent slopes
Totals for Area of Interest
Description
5.5 I 100,0%
5.51 100.0%
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 Gflndition
Component Percent Cutoff.- None Specified
USDA Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
10/14/2021
Page 3 of 4

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10/14/21, 9:56 AM Precipitation Frequency Data Server
NOAA Atlas 14, Volume 2, Version 3
Location name: Raeford, North Carolina, USA' r1-4
Latitude: 35.0462°, Longitude:-79.3388' ���{I►
Elevation: 462.95 tr
Ij 'source: ESRI Maps
" source: USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
G M Bonnin, D Martin, 8 Lin, T. Partybok, M.Yekta, and D Riley
NOAA, National Weather Service, Silver Spring, Maryland
PF tabular I PF graphical I Maps & aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1
Average
recurrence interval (years)
puration
0 2 0 10
25 50 100 2001 500 1000
5 min
0.437 1
0.516 0.602
0.666
0.742
0.796
0.848
0.897
0.956
1.00
(0.398-0.483
0.471-0.570 0.548.0.664
( 0 605-0.733
0-671.0.815
0.718-0.874
0.761-.0.930
0 800-0.983
0.846-1.051
(0.880 1.10
0.699
0.826 0.963
1.07
1.18
1.27
1.35
1.42
1.51
1.58
10arlin
(0 636-0.771)
J(0.753-0.912 0.878-1.06
(0 967-1.1 7
1.07-1.30)
1.21-1.48
(1 27-1.56)
1(1 34-1.66
1.39-1.73
0.873
1.04 1.22
1.35
1.50
1.61
1.70
1.79
1.90
1.98
15-rrlin
(0.796-0,963)1(0946-115
111-135)
122-1.49
136-1.65
1.45-176
153-1.87
160-1.97
168-2.09
1.74-217
30{T1in
3
744)
1 09��32
(� 3141368)
(1 58 191)
[1.779515)
(2.01 2F-272Z
(? S 72G5
P 34-286)
2 49,0G
j (2.6a33
(2 2 3152}
1.49
1.80
2.22
2.54
2.96
3.28
3.60
3.92
4.35
4.68
60 min
1 36-1 Cu(1164.1
99
(2 02-2 45
(2.31 B0
. fir _3.25
2 967.50
3 22.3 94
3 50-4_^L 9
3 64 4
4 11-5 14
2-hr
1.75
1.58-1 95
2.12
2.65
1 (240.2.66)
3.07
(2 77-3 41)
3.62
11 (3.24-4.02)
4.05
(3 62-4 50)
4.49
[3.99.4.99}
4.94
(4 36-5.48)
5.54
1(4 84-6 1
6.02
5 22-6.68)
3-hr
1.85
2.24
11 2.82
1 3.28
1 3.92
4.44
4.97
5.53
6.32
6.96
(1 67-2 07)
1 (2 03-2 50)
11 (2.55-.3.15)
1 (2.96.3.66)
1 (3.51.4.36)
1 (4.39-5.52)
(4 85-6 14)
(6.48.7 01)
1(5 96-T 72)
6-hr
2 0 2045
2 2--2796)
3.05-3.73)
f3.54-4.34
(4.215019)
4 5-5 88)
5 30-6 84
5 8777036
8.8.48844
7 5 9832)
2.60
3.14
3.99
4.67
5.64
6.44
7.28
8.19
9.49
10.6
12-hr
(2 35-2 89)
(2 85-3 50
3 604 43
4- 1-5.18
5.04-6.23
5 71-7 10
6.40=8 02
7 12.9.01]
6.12-10.4
[$.90-11 6
24-hr
3.05
3.69
4.67
5.44
6.51
7.36
8.23
10.4
11.4
(2.83-3.31
(3 42-4 01
4.32-5.0G
r
(5.02-a.89
5.98-7.04
G 74-7.95
(7.52.8.90
8
[9.4f 11 2
10.3-12.3
2�ay
F-7355-
E11)
(3 30 3583)
(3 98 4862
4.99-5 79
5.78 6472
6. 54299
7 0 9700
(B 57-310 1
.(9
(10 7- 2.S)
(11 6- 3 8)
3.77
4.64
5.66
6.55
7.77
8.74
9.75
10.8
12.2
13.3
3-day
(3 51-4 04)
4 23-4 87
5.27=6 07
(6.09.7.02)
1 (7 20-8 32
8.D7-9.37
8 97-10.4
9 88-11,6
11 1-13.1] j1.2.1-14.3}
3.98
4.79
5.94
6.86
8.12
9.12
10.2
11.2
12.7
13.8
4�ay
3 73-4 26
4 48-5 12
(5 55.6 34)
(E.40.7 31)
1 (7 54-8 66)
{6 45.9.73
9 37-10,6
10 3-12 0
(11 6-13.6) 11(12
6-14.8
7�ay
4.61
5.52
6.76
7.75
9.10
10.2
11.3
12.4
14.0
15.2
(4 32-4 93)
(5 16-5 90)
(6 31-7-23)
(7.2-6:28)
(6.46.9 73)
( 9.45.10.])
(10 4-12 1)
( 11.5-13.3)
(12 8-15 0)
(13.9-16.4)
7-77377F-7-6-
0
10-day
74-15
4 g85962
5.93 fi070
7. 58108
6. 0 9316
(9.3P 10.6
10(4- 1.8
11 4-13.0
1214-14.2
13 6
(1416
1
41
8.41
9.99
11.2
12.9
14.2
15.5
16.8
18.6
20.1
20�iay
?
5.7 7 53
7 95-8.92)P�(11
2-10 8
10.6-11.9)
12 1-13 7
13.3-15.0
14 5-16 4
(15 7-17.9 )
17.119 B
18 5-21.3
30-day
( 8.83
B 35 9.34
10.4 2.2
9 85-11 05-12.9
13.5
12 7-14.3
6
15.3
14 4-16
16.6
15 7-17 G
18.0
16 9-19 1
19.3
18 1-20.5
21.1
19.7-22.5
22.5
21.0.24.0
45�1ay
0.1)
(10 6 111.6)
(12 4-13.8) 413-15.9)
(1516
5)
[1715--19.5)
(18.8
.1 2 6)
(21 4� 4 1
23214 6.1
(24.3-27.5)
60{iay
9--16
8.24.4
12 7- 4 1
14 5 1fi 9- B 7
1814-20.5
2024- 2 7
(21
23.3-26 0
24262 6
2624.29 7
2728--1.3
Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).
umbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval The probability that precipitation frequency estimates (for
a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5% Estimates at upper bounds are
not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values
Please refer to NOAA Atlas 14 document for more information
Back to Top
PF graphical
https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=35.0462&Ion=-79.3388&data=depth&units=english&series=pds 1/4

Scott Cole, NCLSS
312 Copples Road Ext
Asheboro, NC 27205
[phone]
Double D Engineering, PLLC
Attn: Mr, Lee Humphrey
150 S. Page Street
Southern Pines, NC 28387
September 21, 2021
Re: Seasonal High -Water Table Identification and Soil Infiltration Rates: Proposed McCain Gas Station;
Hoke County NC Parcel (Altparno) 19186 (6797 Aberdeen Road, Raeford, NC)
Soil conditions and infiltration rates were evaluated and measured on the above -referenced property within
the proposed storm water BMP device. Work was conducted in accordance with Parts A-2 and C-1 of the
North Carolina Department of Environmental Quality Stormwater Design Alamual. Soil samples were
evaluated with a hand auger.
SEASONAL HIGH WATER TABLE IDENTIFICATION
Seasonal High Water Table depth is determined by field evaluation for soil wetness conditions which are
indicated by the presence of redoximorphic (redox) features with a chroma of 2 or less (in Munsell color
notation) in mottles or the horizon matrix. Colors of chroma 2 or less due to relic minerals from parent
material (underlying rock), anaerobic activity created by placement of fill material, or soil textural class
transitions (perched water) are not considered as indicators for seasonal high water. Upon determination
of SHWT depth, an additional 6" will be deducted fi-om the observed depth to account for capillary fringe
water movement above the SHWT. Stormwater infiltration trenches are designed to ensure the lowest point
is at least two feet above the Seasonal High Water Table (SHWT).
The SHWT for this r7rolect was not observed within 15' of the around surface. Soil conditions
evaluated to elevation 4221.
SATURATED HYDRAULIC CONDUCTIVITY (K at)
Soils evaluated across most of this property are typical of those within the Blaney Loamy Sand series (BaB).
These are deep, well drained, moderately permeable soils often found on side slopes and narrow ridges.
Infiltration rates were measured to determine if soil conditions were suitable for the installation of
stormwater infiltration trenches. Infiltration rates were measured using a Johnson Constant Head
Permeameter. Measurements were recorded at varying intervals until equilibrium was reached.
A summary of observations within the proposed Stormwater BMP Device is shown in the table below,
BMP Device Site
Test Location
SHWT
Munsell Color
Ksat 4l
Ksat #2
(feet below
Notation
round surface
1
Not Observed
N/A
0-4'
4'-15'
within 15' of
Loamy Sand I
Loamy Sand !
ground surface
Sand
Sandy Loam
18" / hour
10" / hour

Scott Cole, NCLSS
312 Copples Road Ext
Asheboro, NC 27205
[phone]
CONCLUSION
Field evaluation of hydraulic conductivity provides estimations of soil infiltration rates; however, methods
used to measure these rates can influence the results. Side walls of the bore hole are "smeared" by the soil
auger as the hole is prepared and loose soil in the bottom of the hole is placed in suspension when water is
applied; both of these factors negatively influence water infiltration rates. To help overcome these issues,
after excavation of each infiltration trench, it is recommended the trench bottom and sidewalls be raked and
dusted with pulverized limestone. These are practices that have been in place within the on -site wastewater
industry to help loosen the soil and aid in restoration of soil structure.
I am pleased to be of service in this matter and can be contacted at your convenience should you have any
questions concerning infonnation within this report.
Thank ou,
Scott Cole
North Carolina Licensed Soil Scientist
eoK sNKLQ
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C;

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Vn CPI
r
458
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4
Parcel: 1918.6
At IL
Isis
1 OjA0 no shwt pp
BMP Site
SHWT: Not Observed within 115'of surface Solt 8C
Ksat 0-4 Loamy Sand I Sand: 25" 1 hour z
■Ksat 4-15' Loamy Sand I Sandy Loam: 10" hour N �9,JkNkKtl
12 '6
1 inch = 100 feet

_ AFC
470
f
•_. z"
F
C �
ti.
R -
+ s.4fr r.a shwl 9 �0
{ `
BMP Site
SHWT: Not Observed within 15' of surface r+. ��o IL
:• I Ksat 0-4' Loamy Sand/ Sand: 25" / hour
'0 ' " Ksat 4-15Loamy Sand f Sandy Loam: 101 hour J ryNK Y'
�
1 inch = 100 feet°
Source: Esri Maxar,GI •ye. Earthslar Geografhics C'�lE:=r. ir? i,it "' �I_' i =•.

WATER QUANTITY -INFILTRATION BASIN

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
PROJECT INFORMATION
1
Project Name
McCain Gas Station
2
Pro'ect Area (ac)
5.096
3
Coastal Wetland Area (ac)
_
4
Surface Water Area (ac)_
5
Is this project High or Low Density?
High
6
Does this project use an off -site SCM?
No
COMPLIANCE WITH 02H .1003(4)
7
Width of vegetated setbacks provided feet
N/A
8
Will the vegetated setback remain vegetated?
N/A
9
If BUA is proposed in the setback, does it meet NCAC 02H.1003(4)(c-d)?
_
No
10
Is streambank stabilization proposed on this project?
No
NUMBER AND TYPE OF SCMs:
11
Infiltration System
1
0
12
Bioretention Cell
13
Wet Pond
0
14
Stormwater Wetland
0
15
Permeable Pavement
0
16
Sand Filter
0
17
Rainwater Harvesting RWH)
0
18
Green Roof
0
19
Level Spreader -Filter Strip (IS-FS)
0
20
Disconnected Impervious Surface (DIS)
0
21
Treatment Swale
0
22
Dry Pond
0
23
StormFilter
0
0
24
Silva Cell
25
Bayfilter
0
26
Filterra
0
FORMS LOADED
DESIGNER CERTIFICATION
27
Name and Title:
Carlo Pardo, PE
Bowman North Carolina, Ltd.
4006 Barrett Drive, Suite 104
28
Organization:
29
Street address:
City, State, Zip:
30
Raleigh, NC 27609
919-553-6570
[e-mail]
31
Phone number(s): _
Email:
32
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.
�����ltliililll11j11
ESS
_ SEAL
051571 -
T
3 lo%
Date

DRAINAGE AREAS
1
Is this a hi h density project?
Yes
2
If so, number of drainage areas/SCMs
1
3
Does this project have low density areas?
No
4
If so. number of low density draina a areas
0
5
Is all/part of this project subject to previous rule
versions?
No
FORMS LOADED
DRAINAGE AREA INFORMATION
Ent re Site
1
4
Type of SCM
-
Infiltration Basin
5
Total drainage area (sq ft)
221969 sf
149468
6
Onsite drainage area (sq ft
134646
7
Offsite drainage area (sq ft
14822
8
Total BUA in project (sq ft)
65624 sf
91439 sf
9
New BUA on subdivided lots (subject to permitting)
(sq ft
10permitting)
New BUA not on subdivided lots (subject to
s
11
Offsite BUA (sq ft
14822 sf
12
Breakdown of new BUA not on subdivided lots:
Parking (sq ft
56714 sf
56714 sf
Sidewalk (sq ft
1910 sf
1910 sf
Roof (sq ft)
7000 sf
7000 sf
Roadway s ft
Future (sq ft)
10993 sf
Other, please specify in the comment box
below (sq ft
13
New infiltrating permeable pavement on
subdivided lots (sq ft
14
New infiltrating permeable pavement not on
subdivided lots s ft
15permitting)
Existing BUA that will remain (not subject to
s ft
13158 sf
16
Existing BUA that is already permitted (sq ft
17
Existing BUA that will be removed (sq ft
2091 sf
2091 sf
18
Percent BUA
29.56%
61.2%
19
Design storm inches
1.0 in
20
Design volume of SCM (cu ft)
7481 cf
21
Calculation method for design volume
Simple Method
ADDITIONAL INFORMATION
Please use this space to provide any additional information about the
22 drainage area(s):
Entire Site: Existing 19,988 sf Impervious Area
Future: Existing Impervious area that will be future NCDOT roadway

INFILTRATION SYSTEM
1 Drainage area number 1
2Minimum required treatment volume (cu ftl 7481 cF��
3
Is the SCM sized to treat the SW from all surfaces at build -out?
Yes
4
Is the SCM located away from contaminated soils?
Yes
5
What are the side slopes of the SCM (H:V or enter "Vertical' for
trenches)?
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 overflow or bypass for inflow volume in excess of the
design volume?
Yes
9
lWhat is the method for clewatering the SCM for maintenance?
Pump (preferred)
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)?
N/A
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 devicespecific MDC?
Yes
17 lWas
the SCM designed by an NC licensedprofessional?
Yes
INFIITRATW
W CVSTFM Mnr FRnm NH _inrl
18 1
Proposed slope of the subgrade surface (%)
0%
19
Are terraces or baffles provided?
No
20
T e of retreatment:
Forebay
Isnf/a Onto
21
Was the soil investigated in the footprint and at the elevation of the
infiltrations stem?
Yes
22
SHWT elevation fmsl
< 422.0
23
Depth to SHWT per soils re ort (in)
> 15ft
24
Ground elevation at boring in soils report (fmsl)
437.00
25
Is a detailed hydrogeologic study attached if the separation is
between 1 and 2 feet?
N/A
26
ISoil infiltration rate in/hr
9.00
27 j
Factor of safety (FS) (2 is recommended):
2.00
Elevations
29 Bottom elevation (fmsl)
436 ft
30 Storage elevation (fmsl)
437.3 ft
31 By ass elevation (fmsl)
439.4 ft
For Basins Dnl
32 Bottom surface area ft2
5311511
33 Store a elevation surface area (ft)
6560. ft
Fnr Trenches Only
34
Length (ft)
35
Width (ft)
36
Perforated pipe diameter, if applicable (inches)
37
Number of laterals
38
Total length of perforated piping
39
Stone type, if applicable
40
Stone porosity (%)
41
Is stone free of fines?
42
Is the stone wrapped in geotextile fabric?
43
Has at least one inspection port been provided?
volumesiurawaown
44 Design volume of SCM (cu ft) 7481 cf
45 1 Time to draw down hours 3.7 hrs
ADDITIONAL INFORMATION
46 Please use this space to provide any additional information about the
infiltration system(s):
Line 26-The infiltration rate was intentially lowered to half of the 18 in/hr to account for
cloaainc of the soils that will haooen over time.
nfiltration 1 11:11 AM 3/10/2022

3,

Bowman North Carolina, Ltd.
McCain Gas Station, Raeford, Hoke County, NC
Curve Number Calculation (CN)
Pre -Developed Conditions
Drainage Area (acres 5.41
Existing Soil Grau s
Soil Group Map Symbol
C BaB
Existing Land Uses:
Land Use Description
Wooded - Good Stand
Open Space - Good Stand
Impervious -Gravel
Impervious -Parking
Soil Description Acres Percent of DA
Blaney Loamy Sand 5.41 100,
Existing Soil GmiT
Acres Curve #
Wer�ghted CN
C
3.66 74
50.1
C
1.00 77
14.2
C
0.17 90
2.8
C
0.58 98
10,5
Cumulative Curve # =
77.6

Bowman North Carolina, Ltd.
McCain Gas Station, Raeford, Hoke County, NC
Curve Number Calculation
(CN)
Post -Developed Conditions
Drainage Area (acres L 3.43
Existing Soil Groups.
Sod Group Map Symbol Soil Description
Acres
Percent of DA
C BaB Blaney Loamy Sand
3.43
100%
Proposed Land Uses:
Land Use Description Existing Soil Group
Acres
Curve #
Weti hted CN
Wooded - Good Stand C
0.39
74
8.4
Open Space - Good Condition C
0.94
77
21.1
Impervious Area -Existing C
0.41
98
11.7
Impervious Area -Proposed C
1.69
98
48.3
Cumulative Curve # =
89.5

Bowman North Carolina, Ltd.
McCain Gas Station, Raeford, Hoke County, NC
Curve Number Calculation (CN)
Post -Developed Conditions Bypass
Drainage Area (acres) 1.98
Existina Soil Grouvs
Soil Grouo Map Symbol
Soil Description
Acres
Percent of DA
!
C BaB
Blaney Loamy Sand
1.98
100%
Proposed Land Uses'
Land Use Description
Existing Soil Group
Acres
Curve #
Weighted CN
Wooded - Good Stand
C
0.41
74
15.3
Open Space - Good Condition
C
1.30
77
50.6
Impervious Area
C
0.27
98
13.4
Cumulative
Curve # =
79.2

Infiltration Basin Design
Site Information
Sub Area Location:
Drainage To Infiltration Basin
Drainage Area (DA) =
3,43 Acres 149468 sf
Impervious Area (IA) =
2.10 Acres 91439 sf
Percent Impervious (1) =
61.2 %
Required Water Quality Volume
Design Storm =
1 inch
Determine Rv Value =
0.05 + .009 (1) = 0.60 in/in
Water Quality Volume =
0.172 ac-ft
Water Quality Volume =
7,481 cf
Water Quality Volume =
0.601 inches of runoff
NOAA 1- ear, 24-hour event = 3.05 inches
Minimum Surface Area
SA =
(12-FS"DV)/(K"T)
Factor of Safety (FS) =
2
Design Volume (DV) =
7480.7 cf
Hydraulic Conductivity of Soil =
9.00 in/hr
Max Dewatering Time =
72 hours
SA =
277.1 sf
Drawdown Time
T =
FS - (DV`12)/(K*SA)
Factor of Safety (FS) =
2
Design Volume (DV) =
7480.7 cf
Hydraulic Conductivity of Soil =
9.00 in/hr
Surface Area Provided =
5385 sf
Drawdown Time =
3.7 hours

Z

STAGEJSTORAGE TABLE
INFILTRATION BASIN
STAGE
ELEVATION
CONTOUR
INCREMENTAL
TOTAL
(FT)
(FT)
AREA (SF)
STORAGE (CF)
STORAGE (CF)
0.0
436.0
5385
0
0
1.0
43ZO
6275
5830
5830
1.3
437.3
6560
1925
7755 (WOv)
2.0
438.0
7230
4827
12582
3.0
439.0
8235
7733
20314
4.0
440.0
9300
8768
29082
5.0
441.0
10420
9860
38942
STORMWATER MANAGEMENT DESIGN
INFILTRATION BASIN
RIVER BASIN:
LUMBER
RECEIVING STREAM:
MOUNTAIN CREEK
STREAM INDEX:
14-2-16-(2)
STREAM CLASS:
C
HUC:
03040203
POND DESIGN SUMMARY
DRAINAGE AREA TO POND: 3.43 ACRES
SITE IMPERVIOUS AREA TO POND:
1.69
ACRES
OFF -SITE DESIGN IMPERVIOUS AREA
TO POND:
0.41
ACRES
TOTAL DESIGN IMPERVIOUS AREA TO
POND:
2.10
ACRES
PRE -DEVELOPED
POST -DEVELOPED
POST -DEVELOPED
POST -DEVELOPED POST -DEVELOPED
THROUGH POND
BYPASS COMBINED
DRAINAGE AREA:
3.43 AC
3.43 AC
1.98 AC
CURVE NUMBER:
77.6
89.5
79.2
INFILTRATION RATE: 9.0 IN/HR
1.0" STORM EVENT:
0.818 CFS
0.000 CFS
1-YEAR STORM EVENT:
8.767 CFS
11.25 CFS
0.000 CFS
3.498 CFS
3.498 CFS
2-YEAR STORM EVENT:
12.52 CFS
14.42 CFS
0.000 CFS
4.927 CFS
4.927 CFS
10-YEAR STORM EVENT:
23.82 CFS
23.05 CFS
0.000 CFS
9.137 CFS
9.137 CFS
1 DO -YEAR STORM EVENT:
42.80 CFS
36.64 CFS
18.08 CFS
16.12 CFS
34.20 CFS

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Hydrograph Report
Hydraflow Hydrographs Extension for AutoCADO Civil 3D® 2009 by Autodesk, Inc. v6.066 Wednesday, Nov 3, 2021
Hyd. No. 3
Post Through SCM
Hydrograph type
= Reservoir
Peak discharge
= 18.08 cfs
Storm frequency
= 100 yrs
Time to peak
= 12.03 hrs
Time interval
= 2 min
Hyd. volume
= 16,757 cuft
Inflow hyd. No.
= 2 - SCM Post -Developed
Reservoir name
= BMP Pond
Max. Elevation
= 440.20 ft
Max. Storage
= 30,902 cuft
Storage Indication method used. Exfiltration extracted from Outflow.
Hydrograph Discharge Table
( Printed values - 1.00% of Qp )
Time
Inflow
Elevation
Clv A Clv B Clv C PfRsr
Wr A
Wr B Wr C Wr D
Exfil
Outflow
(hrs)
cfs
ft
cfs cfs cfs cfs
cfs
cfs cfs cfs
cfs
cfs
11.93
36.64 <<
439.58
----- ----- ----- -----
2.052
----- -- --
1.845
2.052
11.97
35.13
439.96
----- ----- -_--- ---
10.89
----- ----- -----
1.928
10.89
12.00
27.39
440.15
----- - ---- -----
16.94
----- ----- _---
1.973
16.94
12.03
17.15
440.18 <<
----- ----- ----- ---
18.08
----- ----- -----
1.981
18.08 <<
12.07
9.404
440.12
----- ----- ----- -----
15.77
----- ----- -----
1.965
15.77
12.10
5.826
440.01
----- ----- - --- ----
12.49
----- -_--- -----
1.941
12.49
12.13
4.776
439.91
---- ----- ----_ -----
9.492
----- - --- -----
1.918
9.493
12.17
4.570
439.83
----- ----- -- -- - --
7.426
----- ----- -----
1.900
7.426
12.20
4.376
439.78
---- ----- ----- _- -
6.018
----- ----- -----
1.888
6.018
12.23
4.181
439.73
_---- ----- ----- -- --
5.031
----- ----- -----
1.878
5.031
12.27
3.987
439.70
-- -- ----- -----
4.263
----- ----- ----
1.871
4.263
12.30
3.792
439.67
- - ----- ----- -----
3.736
----- - - -----
1.865
3.736
12.33
3.596
439.65
----- ----- -_--- -----
3.288
----- - -- -----
1.860
3.288
12:37
3.401
439.63
----- - -- --- --
2.901
----- ----- -----
1.855
2.901
12.40
3.205
439.61
----- ---- -_-- - --
2.560
----- ----- -
1.851
2.560
12.43
3.009
439.60
-- - -- ----- -----
2.268
----- ----- - -
1.848
2.268
12.47
2.813
439.58
----- -- ----- -----
2.044
----- - -- -
1.845
2.044
12.50
2.616
439.57
--_-- - - ----- -----
1.825
----- ----- -----
1.841
1.825
12.53
2.435
439.55
---- - -- ---- -----
1.612
----- -----
1.838
1.612
12.57
2.300
439.54
----- ----- ----- -----
1.410
----- --- -
1.835
1.411
12.60
2.214
439.53
----- ----- ----- -----
1.226
----- -- __
1.833
1.226
12.63
2.160
439.52
----- ----- - -----
1.064
----- - -----
1.830
1.064
12.67
2.115
439.51
----- ----- ----- -----
0.923
----- ----- -----
1.828
0.923
12.70
2.070
439.50
----- ----- ----- -----
0.810
----- ----- -----
1.826
0.810
12.73
2.026
439.49
----- ----- ----- -----
0.747
----- - _ -----
1.825
0.747
12.77
1.981
439.48
----- ----- ----- -----
0.687
----- --- -----
1.823
0.687
12.80
1.936
439.48
----- - _-- ----- -----
0.628
---- ----- -----
1.821
0.628
12.83
1.892
439.47
----- ----- -_- -----
0.571
----- ----- -----
1.820
0.571
12.87
1.847
439.46
----- ----_ ----- -----
0.516
----- ----- -----
1.818
0.516
12.90
1.802
439.46
----- ----- ----- -----
0.461
----- ----- ----
1.817
0.461
12.93
1.757
439.45
----- ----- ----- -----
0.408
----- ----- -----
1.815
0.408
12.97
1.713
439.44
----- ------ ----- -----
0.356
----- ----- -----
1.814
0.356
13.00
1.668
439.44
----- --- ---
0.305
----- ----- -----
1.813
0.305
13.03
1.625
439.43
----- ----- -----
0.255
----- ----- -----
1.811
0.255
13.07
1.589
439.43
-- -- - ----- -----
0.206
----- ----- ----
1,810
0.206
End
use .l-hrs

11/1/21, 3:26 PM
ECMDS 7.0
NORTH
AMERICAN
GREEN
SPILLWAY ANALYSIS
> > > Grass Spillway
North American Green
5401 St. Wend el -Cynthia na Rd.
Poseyville, Indiana 47633
Tel. [phone]
> Fax [phone] -
www.nagreen.com
ECMDS v7.0
Name
Grass Spillway
Discharge
18.08
Peak Flow Period
1.5
Channel Slope
0.3333
Channel Bottom Width 10
Low Flow Liner
Retardence Class
C 6-12 in
Vegetation Type
Mix (Sod and Bunch)
Vegetation Density
Very Good 80-95%
Soil Type
Sandy Loam (GM)
Shoremax - Class C - Mix (Sod & Bunch) - Very Good 80-95%
Normal
Permissible
Calculated
Safety
Staple
Phase
Reach Discharge
Velocity
Mannings N
Remarks
Depth
Shear Stress
Shear Stress
Factor
_
Pattern
Shoremax w/
Straight 18.08 cfs
10.24 ft/s
0.18 ft
0.026
8.5 Ibs/ft2
3.67 Ibs/ft2
2.32
STABLE
F
P300
Unvegetated
Underlying
Straight 18.08 cfs
10.24 ft/s
0.18 ft
0.026
5.68 Ibs/ft2
3.55 Ibs/ft2
1.6
STABLE
F
Substrate
Shoremax w/
Straight 18.08 cfs
9.79 ft/s
0.18 ft
0.028
14 Ibs/ft2
3.84 Ibs/ft2
3.64
STABLE
F
P300 Reinforced
Vegetation
Underlying
Straight 18.08 cfs
9.79 ft/s
0.18 ft
0.028
8.5 Ibs/ft2
3.71 Ibs/ft2
2.29
STABLE
F
Substrate
https:Hecmds.com/project/139235/spillway-analysis/213335/show 1 /1

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Pond Report
Hydra Flow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Thursday, 03 / 10 / 2022
Pond No. 1 - BMP Pond
Pond Data
Contours -User-defined contour areas.
Average end area method
used for volume calculation. Begining Elevation = 436.00 ft
Stage / Storage Table
Stage (ft) Elevation (ft)
Contour area (sgft)
Incr. Storage (cuft)
Total storage (cuft)
0.00 436.00
5,385
0
0
1.00 437.00
6,275
5,830
5,830
1.30 437.30
6,560
1,925
7,755
2.00 438.00
7,230
4,827
12,582
3.00 439.00
8,235
7,733
20,314
4.00 440.00
9,300
8,768
29,082
5.00 441.00
10,420
9,860
38,942
Culvert / Orifice Structures
Weir Structures
[A]
[B]
[C]
[PrfRsr]
[A]
[B]
[C]
[D]
Rise (in)
Inactive
Inactive
Inactive
Inactive
Crest Len (ft)
= 10.00
0.00
0.00
0.00
Span (in)
= 0.00
0.00
0.00
0.00
Crest El. (ft)
= 439.40
0.00
0.00
0.00
No. Barrels
= 0
0
1
0
Weir Coeff.
= 2.60
3.33
3.33
3.33
Invert El. (ft)
= 0.00
0.00
0.00
0.00
Weir Type
= Broad
---
---
---
Length (ft)
= 0.00
0.00
0.00
0.00
Multistage
= No
No
No
No
Slope (%)
= 0.00
0.00
0.00
n/a
N-Value
= 013
.013
.013
n/a
Orifice Coeff.
= 0.60
0.60
0.60
0.60
Exfil.(in/hr)
= 9.000 (by
Contour)
Multistage
= n/a
No
Yes
No
TW Elev. (ft)
= 0.00
Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet cc) control Weir risers checked for orifice conditions (ic) and submergence (s)
Stage (ft) Stage I Discharge
V Vv0.00 6.00
- Total Q
12.00 18.00 24.00 30.00 36.00 42.00 48.00 54.00
Elev (ft)
441.00
440.00
439.00
438.00
437.00
436.00
60.00
Discharge (cfs)

Hydrograph Summary Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D0 by Autodesk, Inc. v2022
Hyd.
No.
i
Hydrograph
type
(origin)
Peak
flow
(cfs)
Time
interval
(min)
Time to
Peak
(min)
Hyd. Inflow
volume hyd(s)
(cult)
Maximum
elevation
(ft)
Total
strge used
(cuft)
Hydrograph
Description
1
SCS Runoff
8.767
2
722
23,105
-•••-
SCM Pre -Developed
2
SCS Runoff
11.25
2
716
23,197
--
---
------
SCM Post -Developed
3
Reservoir
0.000
2
854
0
2
437.61
9,886
Post Through SCM
4
SCS Runoff
3.498
2
722
9,172
------
-----
------
SCM Post -Developed Bypass
6
SCS Runoff
0.818
2
146
3,527
------
-- -
---
1.0 Post -Developed to SCM
7
Reservoir
0.000
2
210
0
6
436.18
1,059
1.0inPostThrough SCM
Infiltration.gpw
Return Period: 1 Year
Thursday, 03 / 10 / 2022

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Hyd. No. 1
SCM Pre -Developed
Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
Drainage area
= 5.410 ac
Basin Slope
= 0.0 %
Tc method
=
Total precip.
= 3.05 in
Storm duration
= 24 hrs
Thursday, 03 / 10 / 2022
Peak discharge
= 8.767 cfs
Time to peak
= 722 min
Hyd. volume
= 23,105 cuft
Curve number
= 77.6
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 10.40 min
Distribution
= Type II
Shape factor
= 484
SCM Pre -Developed
Q (cfs) Hyd. No. 1 -- 1 Year Q (cfs)
10.00 10.00
8.00 8.00
6.00 6.00
4.00 4.00
2.00 2.00
000 000
0 U0 240 MO 480 600 720� 840 960 —fb8d 1200 1320 1440 1564
Hyd No. 1 Time (min)

3
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 31D® by Autodesk, Inc. v2022
Hyd. No. 2
SCM Post -Developed
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 1 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 3.430 ac
Curve number
Basin Slope
= 0.0 %
Hydraulic length
Tc method
Time of conc. (Tc)
Total precip.
= 3.05 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
12.00
10.00
MIX
.M
4.00
2.00
0.00
�120
Hyd No. 2
SCM Post -Developed
Hyd. No. 2 -- 1 Year
240 -:5,60 480
Thursday, 03 / 10 / 2022
= 11.25 cfs
= 716 min
= 23,197 cuft
= 89.5
= Oft
= 5.00 min
= Type II
= 484
Q (cfs)
12.00
10.00
MM
H. it
4.00
2.00
0.00
�b0 840 __960 TOO ---- f2UG i'20
Time (min)

4
Hydrograph Report
Hydraflow Hydrographs Extension for AutodeskO Civil 3D® by Autodesk, Inc. v2022
Hyd. No. 3
Post Through SCM
Hydrograph type
= Reservoir
Storm frequency
= 1 yrs
Time interval
= 2 min
Inflow hyd. No.
= 2 - SCM Post -Developed
Reservoir name
= BMP Pond
Storage Indication method used. Exfiltration extracted from Outflow.
Q (cfs)
12.00
10.00
M
. Me
4.00
2.00
111150 �
Peak discharge
Time to peak
Hyd. volume
Max. Elevation
Max. Storage
Post Through SCM
Hyd. No. 3 -- 1 Year
Thursday, 03 / 10 / 2022
= 0.000 cfs
= 854 min
= 0 cuft
= 437.61 ft
= 9,886 cuft
Q (cfs)
12.00
10.00
6.00
4.00
2.00
0 -240 -36C 480-- 600 720 840 960 1080 -1200' 1-320- _1440- -1560- 1680
Time (min)
Hyd No. 3 Hyd No. 2 Total storage used = 9,886 cult

6
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Hyd. No. 4
SCM Post -Developed
Bypass
Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
Drainage area
= 1.980 ac
Basin Slope
0.0 %
Tc method
-
Total precip.
= 3.05 in
Storm duration
= 24 hrs
Q (cfs)
4.00
3.00
2.00
1.00
Thursday, 03 / 10 / 2022
Peak discharge
= 3.498 cfs
Time to peak
= 722 min
Hyd. volume
= 9,172 cuft
Curve number
= 79.2
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 10.00 min
Distribution
= Type II
Shape factor
= 484
SCM Post -Developed Bypass
Hyd. No. 4 -- 1 Year
Q (Cfs)
4.00
3.00
2.00
1.00
000
T'2 .2.40 3fi0__ 480 509�T2 �dt7��Q�109{1 1200 1320- -1440 1
Hyd No. 4 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc, v2022
Hyd. No. 6
1.0 Post -Developed to SCM
Hydrograph type =
SCS Runoff
Storm frequency =
1 yrs
Time interval =
2 min
Drainage area =
3.430 ac
Basin Slope =
0.0 %
Tc method -
Total precip. =
1.00 in
Storm duration =
6.00 hrs
7
Thursday, 03 / 10 / 2022
Peak discharge
= 0.818 cfs
Time to peak
= 146 min
Hyd. volume
= 3,527 cuft
Curve number
= 89.5
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 5.00 min
Distribution
= SCS 6-Hr
Shape factor
= 484
1.0 Post -Developed to SCM
Q (cfs) Hyd. No. 6 -- 1 Year Q (cfs)
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
0 �0
Hyd No. 6
1.00
0.90
0.80
- 0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
12fj —18b 240 .301�360 420
Time (min)

8
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Hyd. No. 7
1.0inPost Through SCM
Hydrograph type
= Reservoir
Peak discharge
Storm frequency
= 1 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Inflow hyd. No.
= 6 - 1.0 Post -Developed to SCWax. Elevation
Reservoir name
= BMP Pond
Max. Storage
Storage Indication method used. Exfiltration extracted from Outflow
Thursday, 03 / 10 / 2022
= 0.000 cfs
= 210 min
= 0 cuff
= 436.18 ft
= 1,059 cuft
RIME
IIMM
RIME
1. MIME mm� NICE
0.30
0.20 NEI 'WIli 0 E
4V Time (min)
Hyd No. 7 Hyd No. 6 I Total storage used = 1,059 cult

10
Hydrograph Summary Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Hyd.
I
Hydrograph
Peak
Time
Time to
Hyd.
Inflow
Maximum
Total
Hydrograph
No.
type
flow
interval
Peak
volume
hyd(s)
elevation
strge used
Description
(origin)
(cfs)
12.52
(min)
2
(min)
720
(cuft)
------
(ft)
-
(cuft)
1
SCS Runoff
32,707
SCM Pre -Developed
2
SCS Runoff
14.42
2
716
30,110
------
--
SCM Post -Developed
3
Reservoir
0.000
2
920
0
2
438.09
13,313
Post Through SCM
4
SCS Runoff
4.927
2
720
12,819
------
— -
—
SCM Post -Developed Bypass
6
SCS Runoff
0.000
2
n/a
0
----
-
1.0 Post -Developed to SCM
7
Reservoir
0.000
2
n/a
0
6
436.00
0.000
1.0inPost Through SCM
Infiltration.gpw
Return Period: 2 Year
Thursday, 03 / 10 / 2022

11
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Hyd. No. 1
SCM Pre -Developed
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 5.410 ac
Basin Slope
= 0.0 %
Tc method
=
Total precip.
= 3.69 in
Storm duration
= 24 hrs
Q (Cfs)
14.00
12.00
10.00
• 11
4.00
2.00
0.00
0 120 240
Hyd No. 1
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
SCM Pre -Developed
Hyd. No. 1 -- 2 Year
Thursday, 03 / 10 / 2022
= 12.52 cfs
= 720 min
= 32,707 cuft
= 77.6
= Oft
= 10.40 min
= Type II
= 484
Q (cfs)
14.00
iVA1111
10.00
. 11
4.00
2.00
0.00
360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)

Hydrograph
Report
12
Hydraflow Hydrographs Extension for Aulodesk® Civil 3D® by Autodesk, Inc. v2022
Thursday, 03 / 10 / 2022
Hyd. No. 2
SCM Post -Developed
Hydrograph type
= SCS Runoff
Peak discharge
= 14.42 cfs
Storm frequency
= 2 yrs
Time to peak
= 716 min
Time interval
= 2 min
Hyd. volume
= 30,110 cuft
Drainage area
= 3.430 ac
Curve number
= 89.5
Basin Slope
= 0.0 %
Hydraulic length
= 0 ft
Tc method
-
Time of conc. (Tc)
= 5.00 min
Total precip.
= 3.69 in
Distribution
= Type II
Storm duration
= 24 hrs
Shape factor
= 484
SCM Post -Developed
Q (cfs) Hyd. No. 2 -- 2 Year Q (cfs)
15.00 15.00
12.00 - 12.00
9.00 9.00
6.00 6.00
3.00 3.00
0.00 0.00
1 0 240 36 480 _66o no 840 960 96801260 1320
Hyd No. 2 Time (min)

13
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Hyd. No. 3
Post Through SCM
Hydrograph type
= Reservoir
Peak discharge
Storm frequency
= 2 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Inflow hyd. No.
= 2 - SCM Post -Developed
Max. Elevation
Reservoir name
= BMP Pond
Max. Storage
Storage Indication method used. Exfiltration extracted from Outflow.
Post Through SCM
Hyd. No. 3 -- 2 Year
12.00
• II
MIN
MI
Thursday, 03 / 10 / 2022
= 0.000 cfs
= 920 min
= 0 cuft
= 438.09 ft
= 13,313 cuft
Q (cfs)
15.00
12.00
• II
. II
3.00
0.00 -L-- - 1 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 1680
Time (min)
— Hyd No. 3 Hyd No. 2 . Total storage used = 13,313 cuft

14
Hydrograph Report
Hydraflow Hydrographs Extension for Aulodesk® Civil 3D® by Autodesk, Inc. v2022
Hyd. No. 4
SCM Post -Developed Bypass
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 1.980 ac
Basin Slope
= 0.0 %
Tc method
-
Total precip.
= 3.69 in
Storm duration
= 24 hrs
Q (cfs)
5.00 -
4.00
3.00
2.00
1.00
Thursday, 03 / 10 / 2022
Peak discharge
= 4.927 cfs
Time to peak
= 720 min
Hyd. volume
= 12,819 cuft
Curve number
= 79.2
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 10.00 min
Distribution
= Type II
Shape factor
= 484
SCM Post -Developed Bypass
Hyd. No. 4 -- 2 Year
Q (cfs)
5.00
4.00
3.00
2.00
1.00
M
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 4 Time (min)

17
Hydrograph Summary Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Hyd.
No.
Hydrograph
type
(origin)
Peak
flow
(cfs)
Time
interval
(min)
Time to
Peak
(min)
Hyd.
volume
(cult)
Inflow
hyd(s)
Maximum
elevation
(ft)
Total
strge used
(cuft)
Hydrograph
Description
1
SCS Runoff
23.82
2
720
61,796
---
— -
SCM Pre -Developed
2
SCS Runoff
23.05
2
716
49,585
------
- —
SCM Post -Developed
3
Reservoir
0.000
2
746
0
2
439.34
23,328
Post Through SCM
4
SCS Runoff
9.137
2
720
23,742
-•--
—
— -
SCM Post -Developed Bypass
6
SCS Runoff
0.000
2
n/a
0
-•---•
---
-
1.0 Post -Developed to SCM
7
Reservoir
0.000
2
n/a
0
6
436.00
0.000
1.OinPost Through SCM
Infiltration.gpw
Return Period: 10 Year
Thursday, 03 / 10 / 2022

18
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Hyd. No. 1
SCM Pre -Developed
Hydrograph type
= SCS Runoff
Storm frequency
= 10 yrs
Time interval
= 2 min
Drainage area
= 5.410 ac
Basin Slope
= 0.0 %
Tc method
=
Total precip.
= 5.44 in
Storm duration
= 24 hrs
Q (cfs)
24.00
20.00
16.00
12.00
8.00
4.00
0.00
Thursday, 03 / 10 / 2022
Peak discharge
= 23.82 cfs
Time to peak
= 720 min
Hyd. volume
= 61,796 cuft
Curve number
= 77.6
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 10.40 min
Distribution
= Type II
Shape factor
= 484
Q (cfs)
24.00
20.00
16.00
12.00
8.00
4.00
0.00
0 120 246 360 480 600 720 840 960 1080 1200 1320 1440 1560
- Hyd No. 1 Time (min)
SCM Pre -Developed
Hyd. No. 1 -- 10 Year

19
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Thursday, 03 / 10 / 2022
Hyd. No. 2
SCM Post -Developed
Hydrograph type
= SCS Runoff
Peak discharge
= 23.05 cfs
Storm frequency
= 10 yrs
Time to peak
= 716 min
Time interval
= 2 min
Hyd. volume
= 49,585 cuft
Drainage area
= 3.430 ac
Curve number
= 89.5
Basin Slope
= 0.0 %
Hydraulic length
= 0 ft
Tc method
=
Time of conc. (Tc)
= 5.00 min
Total precip.
= 5.44 in
Distribution
= Type II
Storm duration
= 24 hrs
Shape factor
= 484
Q (cfs)
24.00
20.00
16.00
12.00
8.00
4.00
SCM Post -Developed
Hyd. No. 2 -- 10 Year
Q (cfs)
24.00
20.00
16.00
12.00
8.00
4.00
0 120 240 360 480 600 720 840 966 1080 1200-
Hyd No. 2 --
Time (min)

20.00
16.00
12.00
1
4.00
KIN
20
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022 Thursday, 03 / 1012022
Hyd. No. 3
Post Through SCM
Hydrograph type
= Reservoir
Peak discharge
= 0.000 cfs
Storm frequency
= 10 yrs
Time to peak
= 746 min
Time interval
= 2 min
Hyd. volume
= 0 cuft
Inflow hyd. No.
= 2 - SCM Post -Developed
Max. Elevation
= 439.34 ft
Reservoir name
= BMP Pond
Max. Storage
= 23,328 cuft
Storage Indication method used. ExFltration extracted from Outflow.
Q (cfs)
24.00
0 120 240 364 480 600 7
Hyd No. 3 Hyd No. 2
Post Through SCM
Hyd. No. 3 -- 10 Year
Q (cfs)
24.00
20.00
16.00
12.00
4.00
0.00
20 840 960 1080 1200 E3 0
Time (min)
Total storage used = 23,328 cult

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Hyd. No. 4
SCM Post -Developed
Bypass
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 10 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 1.980 ac
Curve number
Basin Slope
= 0.0 %
Hydraulic length
Tc method
=
Time of conc. (Tc)
Total precip.
= 5.44 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs
10.00
4.00
2.00
SCM Post -Developed Bypass
Hyd. No. 4 -- 10 Year
0.00
120 240
Hyd No. 4
21
Thursday, 03 / 10 / 2022
= 9.137 cfs
= 720 min
= 23,742 cult
= 79.2
= Oft
= 10.00 min
= Type II
= 484
Q (cfs)
10.00
ME
4.00
2.00
VAT.>•
360 480 600 720 846 660 1080 1200 1320 1440 1560 Time (min)

24
Hydrograph Summary Report
Hydraflow Hydrographs Extension for Autodesk0 Civil 3D® by Autodesk, Inc. v2022
Hyd. Hydrograph
No. 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
SCS Runoff
42.80
2
720
112,534
-••-
SCM Pre -Developed
2
SCS Runoff
36.64
2
716
81,386
-
-
—
SCM Post -Developed
3
Reservoir
18.08
2
722
16,756
2
440.18
30,901
Post Through SCM
4
SCS Runoff
16.12
2
720
42,590
----
-----
—
SCM Post -Developed Bypass
6
SCS Runoff
0.000
2
n/a
0
- ---
— --
---
1.0 Post -Developed to SCM
7
Reservoir
0.000
2
n/a
0
6
436.00
0.000
1.OinPost Through SCM
Infiltration.gpw
Return Period: 100 Year
Thursday, 03 / 10 / 2022

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D0 by Autodesk, Inc. v2022
Hyd. No. 1
SCM Pre -Developed
Hydrograph type
= SCS Runoff
Storm frequency
= 100 yrs
Time interval
= 2 min
Drainage area
= 5.410 ac
Basin Slope
= 0.0 %
Tc method
=
Total precip.
= 8.23 in
Storm duration
= 24 hrs
Q (cfs)
50.00
40.00
30.00
20.00
10.00
0 00
25
Thursday, 03 / 10 / 2022
Peak discharge
= 42.80 cfs
Time to peak
= 720 min
Hyd. volume
= 112,534 cuft
Curve number
= 77.6
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 10.40 min
Distribution
= Type II
Shape factor
= 484
SCM Pre -Developed
Hyd. No. 1 -- 100 Year
Q (cfs)
50.00
40.00
30.00
20.00
10.00
_ 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 1 Time (min)

26
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Hyd. No. 2
SCM Post -Developed
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 100 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 3.430 ac
Curve number
Basin Slope
= 0.0 %
Hydraulic length
Tc method
=
Time of conc. (Tc)
Total precip.
= 8.23 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
40.00
30.00
20.00
10.00
0.00
SCM Post -Developed
Hyd. No. 2 -- 100 Year
Thursday, 03 / 10 / 2022
= 36.64 cfs
= 716 min
= 81,386 cuft
= 89.5
= Oft
= 5.00 min
= Type II
= 484
0 120 240 360 480 6fl0 720 840 W 1fJ80
Hyd No. 2
Q (cfs)
40.00
30.00
20.00
10.00
�"_ 0.00
1200
Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Hyd. No. 3
Post Through SCM
Hydrograph type
= Reservoir
Storm frequency
= 100 yrs
Time interval
= 2 min
Inflow hyd. No.
= 2 - SCM Post -Developed
Reservoir name
= BMP Pond
Storage Indication method used. Exfiltration extracted from Outflow.
Q (cfs)
40.00
30.00
20.00
10.00
0.00
120
Hyd No. 3
M
Peak discharge
Time to peak
Hyd. volume
Max. Elevation
Max. Storage
Post Through SCM
Hyd. No. 3 -- 100 Year
Hyd No. 2
360
27
Thursday, 03 / 10 / 2022
= 18.08 cfs
= 722 min
= 16,756 cuft
= 440.18 ft
= 30,901 cuft
Q (cfs)
40.00
30.00
20.00
10.00
_ _ 0.00
480 600 720 840
I Total storage used = 30,901 cult Time (min)

Hydrograph
Report
28
Hydraflow Hydrographs Extension for Autodesk a0 Civil 3D® by Autodesk, Inc. v2022
Thursday, 03 / 10 / 2022
Hyd. No. 4
SCM Post -Developed Bypass
Hydrograph type
= SCS Runoff
Peak discharge
= 16.12 cfs
Storm frequency
= 100 yrs
Time to peak
= 720 min
Time interval
= 2 min
Hyd. volume
= 42,590 cuft
Drainage area
= 1.980 ac
Curve number
= 79.2
Basin Slope
= 0.0 %
Hydraulic length
= 0 ft
Tc method
=
Time of conc. (Tc)
= 10.00 min
Total precip.
= 8.23 in
Distribution
= Type II
Storm duration
= 24 hrs
Shape factor
= 484
SCM Post -Developed Bypass
Q (cfs) Hyd. No. 4 -- 100 Year Q (cfs)
18.00 - 18.00
15.00
12.00
15.00
9.00
12.00
-
9.00
6.00
6.00
3.00
0.00
3.00
0.00
0 120 240 360 480 600 720 :84.0 960 1080 1200 1320 1440 1560
Hyd No. 4 Time (min)

mm
§
�
§
,!
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Project Name Riprap Dissipater #1 Date
McCain Gas Station Sept. 2021
DID Project No.
Location Double D Engineering, PLLC DD2114
Hoke County, NC 150 S. Page Street Calculated By
Southern Pines, NC 28387 JLH
[phone] Checked By
JLH
STORM DESIGN: 25 Year
BACKGROUND: Use the E&S Control Planning & Design Manual, Section 8.06.
REFERENCE: (NCDE-WR, 1993)
Step 1. Minimum Tailwater Condition
Step 2.
D-o =
18 in.
D-o =
1.50 ft.
Q-25 =
16.33 cfs
d-50 =
0.5 ft.
L-a =
15 ft.
Step 3.
3*D-o =
4.50 ft,
W =
16.50 ft.
Step 4.
d-max
0.75 ft.
d-max
9 in.
Step 5. Thickness = 1.13 ft
Thickness = 14 in.
IDESIGN DIMENSIONS:
Pipe diameter in inches
Pipe diameter in feet
Pipe outlet (from drainage calculations)
from Figure 8.06 a
from Figure 8.06 a
3 times the outlet pipe diameter
Pipe diameter + Apron length
Maximum Stone Diameter (1.5*d-50) in inches
Maximum Stone Diameter (1.5*d-50) in feet
Min. Apron Thickness With Filter Fabric (1.5*d-max) in feet
Min. Apron Thickness With Filter Fabric (1.5*d-max) in inches
Apron Dimensions
Rlprap
Length
Width
3*D-o
Thick
Class
15
17
5
241n.
1
TERMINOLOGY: Q25 = 25-Year Design Storm, Peak Discharge, (cfs)
D-o = Pipe Diameter, (in. & ft.)
d-50 = Mean Stone Diameter of Rip -Rap, (ft.)
L-a = Length of Rip -Rap Apron, (ft.)
3'D-o = Width of Rip -Rap Apron @ Pipe Outlet, (ft.)
W = Width of Rip -Rap Apron @ End of Apron, (ft.)
d-max = Maximum Stone Diameter of Rip -Rap, (ft, & in.)
Thickness = Thickness of Rip -Rap Apron With Filter Fabric, (ft. &in.)