Stormwater ReportSTORMWATER REPORT
Buy Quick Food Mart
7650 Market Street
Wilmington, North Carolina
for
Khalid Saleh
Matthew C. Kirchner, P.E.
EAGLE ENGINEERING, INC.
2013A Van Buren Ave.
Indian Trail, NC 28079
EEI PROJECT NO.: 7057
December 15, 2020
Initials Date
SAP 03-10-21
03/10/202100000303000030000030003000000000000000000/10/2021
Buy Quick Food Mart – Wilmington 7057
Stormwater Report March 10, 2021
1.0 Project Address and Summary
This project is located at 7650 Market Street, Wilmington, North Carolina in New Hanover County,
about 1.7 miles north of its intersection with Military Cutoff Road. The proposed development will include
construction of a convenience store as well as a vehicle fueling station. The site development activities will
include site grading, building construction, BMP installation, and sanitary sewer and water main service
connections.
Development of this site will include the installation of a stormwater wetland to be used for
stormwater quality. The wetlands has been sized to provide the required water quality and water quantity
volumes per the NCDEQ Stormwater BMP Manual. Detention is also being provided for the 2-, 10-, and 25-
year storm events. In addition, the 100-year storm event is able to pass through the stormwater wetlands with
greater than 6” of freeboard.
Soils on the site consist of:
Kr – Kureb Sand, 1 to 8 percent slopes, Hydrologic Soils Group “A”
Le – Leon Sand, Hydrologic Soils Group “A”
Mu – Murville Fine Sane, Hydrologic Soils Group “A”
2.0 Water Quality / Quantity Volume Control and Peak Flow Control
Water quality volume and release rate calculations were performed and can be found on the following
sheets.
3.0 Predeveloped Conditions
The existing conditions currently consist of a commercial site containing existing buildings, asphalt
and gravel parking lots, as well as minor wooded areas covering primarily the southern end of the site. The
site is bounded by Market Street along on its western edge, commercial properties to the south, east and a
portion of the north, and a private access road along the remainder of the northern property line.
The entire site generally drains to from northwest to the southeast corner of the site, sheet flowing
across the existing land and onto the neighboring southern properties. See the pre-development drainage area
map within this report for existing topography of the site. The time of concentration has been calculated using
TR-55 and is outlined on the drainage area maps, and calculations. Curve Number (CN) for the drainage basin
was computed as a composite average of the various existing land uses in the predevelopment drainage area
and resulting post-development drainage area. Calculations have been included with the hydrographs within
this report.
Pre-Development Area A: CN = 68
Buy Quick Food Mart – Wilmington 7057
Stormwater Report March 10, 2021
4.0 Post Developed Conditions
The development will consist of the construction of a convenience store and a vehicle fueling station, as
well as all required pavement, curb and gutter, sidewalks, and grading to allow the site to function properly.
The stormwater wetland, parking lot, building, and utility infrastructure will be constructed after the
stabilization of all erosion control measures. One stormwater wetland is being proposed to control peak runoff
and provide stormwater quality for the site. Drainage area A also consists of a bypass drainage basin. This
bypass drainage basin consists of all areas outside the limits of the primary drainage basin A, which is being
picked up by the onsite storm drain system and directed to the proposed stormwater wetland. The bypass
basin consists mostly of undisturbed, offsite areas consisting of developed commercial parcels, but some
portion of the basin will be grading and stabilized grass area with a small amount of impervious area. The
combination of the bypass basin with the primary drainage shed has been taken into account when comparing
the pre-development and post development hydrographs and flow rates.
The post development hydrographs have been modeled for the proposed onsite improvements and the
proposed bypass areas and combined for a cumulative comparison to the existing runoff from the site. The
composite Curve Numbers calculated for the post developed basins are the following:
Post Development Area A: CN = 92
Post Development Area Bypass: CN = 66
5.0 Detention Stage/Storage Computations
One Stormwater Wetland has been designed to treat the water quality volume and control the post-developed
peak rate of discharge to below pre-developed discharge rates.
The water quality and stage/storage calculations are included within this report. The rainfall intensities used
are for the 24 hour storm for each storm event for both the pre-developed and post-developed conditions. The
outlet structure for the basin has been placed so that the stage/storage elevation begins at the permanent pool
elevation. Water quality and quantity storage and treatment will be provided above the permanent pool in the
pond.
Buy Quick Food Mart – Wilmington 7057
Stormwater Report March 10, 2021
6.0 Outlet Structures
The outlet structure will be constructed within the stormwater wetland near the downstream end of the pond.
The structure consists of a rip-rap weir with (2) 10” ADS CPP pipes placed through the embankment and has
been designed to efficiently provide water quality control.
7.0 Erosion Control
Erosion control will be provided by utilizing a stabilized construction entrance, perimeter silt fence, and
several silt fence outlets, and skimmer basin and inlet protection for phase 2. Erosion control devices will be
maintained in place until approval by the New Hanover County Inspectors at which time temporary
measures will be removed. Please refer to the construction drawings for locations and quantities of erosion
control measures.
Hydrologic Soil Group—New Hanover County, North Carolina
(Market Street - New Hanover Co)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
10/30/2020
Page 1 of 437971203797130379714037971503797160379717037971803797190379720037972103797220379711037971203797130379714037971503797160379717037971803797190379720037972103797220241500241510241520241530241540241550241560241570241580241590241600241610241620241630241640241650241660241670
241500 241510 241520 241530 241540 241550 241560 241570 241580 241590 241600 241610 241620 241630 241640 241650 241660
34° 17' 2'' N 77° 48' 29'' W34° 17' 2'' N77° 48' 22'' W34° 16' 59'' N
77° 48' 29'' W34° 16' 59'' N
77° 48' 22'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 18N WGS84
0 35 70 140 210
Feet
0 10 20 40 60
Meters
Map Scale: 1:803 if printed on A landscape (11" x 8.5") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Lines
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Points
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:15,800.
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: New Hanover County, North Carolina
Survey Area Data: Version 21, Jun 4, 2020
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Nov 21, 2018—Nov
28, 2018
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.
Hydrologic Soil Group—New Hanover County, North Carolina
(Market Street - New Hanover Co)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
10/30/2020
Page 2 of 4
Hydrologic Soil Group
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
Kr Kureb sand, 1 to 8
percent slopes
A 0.1 4.1%
Le Leon sand A/D 1.2 78.3%
Mu Murville fine sand A/D 0.3 17.6%
Totals for Area of Interest 1.5 100.0%
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.
Hydrologic Soil Group—New Hanover County, North Carolina Market Street - New Hanover Co
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
10/30/2020
Page 3 of 4
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Hydrologic Soil Group—New Hanover County, North Carolina Market Street - New Hanover Co
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
10/30/2020
Page 4 of 4
3/8/2021 Precipitation Frequency Data Server
https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=34.2835&lon=-77.8076&data=depth&units=english&series=pds 1/4
NOAA Atlas 14, Volume 2, Version 3
Location name: Wilmington, North Carolina, USA*
Latitude: 34.2835°, Longitude: -77.8076°
Elevation: 32.84 ft**
* source: ESRI Maps ** source: USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley
NOAA, National Weather Service, Silver Spring, Maryland
PF_tabular | PF_graphical | Maps_&_aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1
Duration Average recurrence interval (years)
1 2 5 10 25 50 100 200 500 1000
5-min 0.521
(0.486‑0.563)
0.620
(0.577‑0.669)
0.725
(0.673‑0.781)
0.806
(0.747‑0.869)
0.910
(0.839‑0.979)
0.989
(0.907‑1.06)
1.07
(0.976‑1.15)
1.15
(1.04‑1.24)
1.25
(1.13‑1.35)
1.34
(1.19‑1.45)
10-min 0.833
(0.776‑0.899)
0.991
(0.922‑1.07)
1.16
(1.08‑1.25)
1.29
(1.19‑1.39)
1.45
(1.34‑1.56)
1.57
(1.45‑1.69)
1.70
(1.55‑1.83)
1.82
(1.65‑1.96)
1.98
(1.78‑2.14)
2.11
(1.88‑2.28)
15-min 1.04
(0.970‑1.12)
1.25
(1.16‑1.34)
1.47
(1.36‑1.58)
1.63
(1.51‑1.76)
1.84
(1.70‑1.98)
1.99
(1.83‑2.15)
2.15
(1.96‑2.31)
2.30
(2.08‑2.48)
2.50
(2.24‑2.70)
2.65
(2.36‑2.86)
30-min 1.43
(1.33‑1.54)
1.72
(1.60‑1.86)
2.09
(1.94‑2.25)
2.36
(2.19‑2.55)
2.72
(2.51‑2.93)
3.00
(2.76‑3.23)
3.29
(3.00‑3.54)
3.58
(3.24‑3.85)
3.97
(3.56‑4.29)
4.29
(3.81‑4.64)
60-min 1.78
(1.66‑1.92)
2.16
(2.01‑2.33)
2.67
(2.48‑2.88)
3.08
(2.85‑3.32)
3.63
(3.34‑3.90)
4.07
(3.73‑4.38)
4.53
(4.13‑4.87)
5.02
(4.55‑5.41)
5.70
(5.11‑6.15)
6.26
(5.57‑6.77)
2-hr 2.11
(1.94‑2.30)
2.57
(2.37‑2.81)
3.27
(3.01‑3.57)
3.85
(3.54‑4.21)
4.70
(4.29‑5.12)
5.42
(4.93‑5.91)
6.21
(5.61‑6.77)
7.08
(6.34‑7.69)
8.36
(7.41‑9.11)
9.46
(8.32‑10.3)
3-hr 2.25
(2.07‑2.47)
2.74
(2.52‑3.01)
3.51
(3.22‑3.84)
4.17
(3.81‑4.56)
5.15
(4.68‑5.62)
6.01
(5.43‑6.56)
6.96
(6.24‑7.59)
8.02
(7.14‑8.73)
9.64
(8.47‑10.5)
11.1
(9.60‑12.1)
6-hr 2.79
(2.57‑3.08)
3.40
(3.14‑3.75)
4.36
(4.00‑4.79)
5.19
(4.75‑5.70)
6.43
(5.85‑7.04)
7.52
(6.79‑8.23)
8.75
(7.85‑9.56)
10.1
(8.97‑11.1)
12.2
(10.7‑13.4)
14.1
(12.2‑15.4)
12-hr 3.27
(2.99‑3.63)
3.99
(3.64‑4.41)
5.14
(4.68‑5.68)
6.15
(5.58‑6.79)
7.68
(6.90‑8.45)
9.04
(8.08‑9.93)
10.6
(9.38‑11.6)
12.3
(10.8‑13.5)
15.0
(13.0‑16.5)
17.4
(14.8‑19.1)
24-hr 3.86
(3.51‑4.30)
4.68
(4.26‑5.23)
6.06
(5.51‑6.76)
7.27
(6.59‑8.09)
9.13
(8.18‑10.1)
10.8
(9.57‑12.0)
12.7
(11.1‑14.1)
14.8
(12.8‑16.5)
18.1
(15.4‑20.3)
21.1
(17.5‑23.7)
2-day 4.58
(4.18‑5.07)
5.53
(5.06‑6.14)
7.10
(6.47‑7.88)
8.47
(7.68‑9.39)
10.5
(9.48‑11.7)
12.4
(11.0‑13.8)
14.4
(12.7‑16.1)
16.8
(14.6‑18.8)
20.4
(17.3‑23.0)
23.5
(19.6‑26.7)
3-day 4.89
(4.47‑5.41)
5.90
(5.40‑6.54)
7.52
(6.86‑8.34)
8.92
(8.10‑9.88)
11.0
(9.93‑12.2)
12.9
(11.5‑14.3)
14.9
(13.2‑16.6)
17.2
(15.0‑19.3)
20.8
(17.7‑23.4)
23.9
(20.0‑27.0)
4-day 5.20
(4.75‑5.75)
6.27
(5.74‑6.94)
7.94
(7.24‑8.79)
9.37
(8.52‑10.4)
11.5
(10.4‑12.7)
13.3
(11.9‑14.8)
15.4
(13.6‑17.1)
17.7
(15.4‑19.7)
21.1
(18.1‑23.8)
24.2
(20.4‑27.4)
7-day 5.98
(5.52‑6.54)
7.20
(6.65‑7.88)
9.06
(8.34‑9.91)
10.6
(9.74‑11.6)
12.9
(11.7‑14.1)
14.8
(13.4‑16.2)
16.9
(15.1‑18.5)
19.2
(17.0‑21.1)
22.5
(19.6‑25.0)
25.4
(21.8‑28.3)
10-day 6.76
(6.25‑7.35)
8.09
(7.49‑8.82)
10.0
(9.26‑10.9)
11.7
(10.7‑12.7)
14.0
(12.8‑15.3)
16.0
(14.5‑17.5)
18.1
(16.4‑19.8)
20.4
(18.3‑22.4)
23.8
(21.0‑26.3)
26.6
(23.1‑29.7)
20-day 9.05
(8.43‑9.76)
10.8
(10.0‑11.6)
13.1
(12.2‑14.2)
15.1
(14.0‑16.3)
17.9
(16.5‑19.3)
20.2
(18.5‑21.8)
22.6
(20.6‑24.5)
25.2
(22.7‑27.4)
28.8
(25.7‑31.6)
31.9
(28.0‑35.2)
30-day 11.1
(10.4‑11.9)
13.2
(12.4‑14.1)
15.8
(14.9‑16.9)
18.0
(16.8‑19.2)
21.0
(19.5‑22.4)
23.3
(21.6‑25.0)
25.8
(23.8‑27.7)
28.4
(25.9‑30.5)
31.9
(28.8‑34.6)
34.7
(31.1‑37.8)
45-day 13.8
(13.0‑14.7)
16.4
(15.4‑17.4)
19.4
(18.3‑20.7)
21.9
(20.6‑23.3)
25.3
(23.7‑27.0)
28.0
(26.1‑29.9)
30.8
(28.6‑33.0)
33.7
(31.0‑36.2)
37.6
(34.2‑40.6)
40.7
(36.7‑44.2)
60-day 16.6
(15.7‑17.6)
19.6
(18.5‑20.8)
22.9
(21.6‑24.3)
25.6
(24.1‑27.1)
29.1
(27.4‑30.9)
31.9
(29.9‑33.9)
34.7
(32.3‑37.0)
37.5
(34.7‑40.1)
41.2
(37.8‑44.3)
44.1
(40.2‑47.7)
1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).
Numbers 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%. Estimatesat 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.
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PF graphical
3/8/2021 Precipitation Frequency Data Server
https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=34.2835&lon=-77.8076&data=depth&units=english&series=pds 2/4
Back to Top
Maps & aerials
Small scale terrain
3/8/2021 Precipitation Frequency Data Server
https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=34.2835&lon=-77.8076&data=intensity&units=english&series=pds 1/4
NOAA Atlas 14, Volume 2, Version 3
Location name: Wilmington, North Carolina, USA*
Latitude: 34.2835°, Longitude: -77.8076°
Elevation: 32.84 ft**
* source: ESRI Maps ** source: USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley
NOAA, National Weather Service, Silver Spring, Maryland
PF_tabular | PF_graphical | Maps_&_aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches/hour)1
Duration Average recurrence interval (years)
1 2 5 10 25 50 100 200 500 1000
5-min 6.25
(5.83‑6.76)
7.44
(6.92‑8.03)
8.70
(8.08‑9.37)
9.67
(8.96‑10.4)
10.9
(10.1‑11.7)
11.9
(10.9‑12.8)
12.8
(11.7‑13.8)
13.8
(12.5‑14.9)
15.0
(13.5‑16.2)
16.1
(14.3‑17.4)
10-min 5.00
(4.66‑5.39)
5.95
(5.53‑6.41)
6.97
(6.47‑7.50)
7.74
(7.16‑8.33)
8.71
(8.03‑9.36)
9.44
(8.67‑10.2)
10.2
(9.30‑11.0)
10.9
(9.91‑11.8)
11.9
(10.7‑12.9)
12.7
(11.3‑13.7)
15-min 4.16
(3.88‑4.49)
4.98
(4.64‑5.38)
5.87
(5.45‑6.33)
6.52
(6.04‑7.03)
7.36
(6.78‑7.91)
7.97
(7.32‑8.58)
8.59
(7.84‑9.24)
9.19
(8.33‑9.90)
9.98
(8.96‑10.8)
10.6
(9.42‑11.5)
30-min 2.85
(2.66‑3.08)
3.44
(3.20‑3.71)
4.17
(3.87‑4.49)
4.73
(4.38‑5.09)
5.45
(5.02‑5.86)
6.00
(5.51‑6.46)
6.58
(6.00‑7.08)
7.15
(6.49‑7.71)
7.94
(7.13‑8.58)
8.57
(7.63‑9.27)
60-min 1.78
(1.66‑1.92)
2.16
(2.01‑2.33)
2.67
(2.48‑2.88)
3.08
(2.85‑3.32)
3.63
(3.34‑3.90)
4.07
(3.73‑4.38)
4.53
(4.13‑4.87)
5.02
(4.55‑5.41)
5.70
(5.11‑6.15)
6.26
(5.57‑6.77)
2-hr 1.05
(0.970‑1.15)
1.28
(1.18‑1.40)
1.63
(1.51‑1.79)
1.93
(1.77‑2.10)
2.35
(2.14‑2.56)
2.71
(2.46‑2.95)
3.10
(2.81‑3.38)
3.54
(3.17‑3.85)
4.18
(3.71‑4.55)
4.73
(4.16‑5.17)
3-hr 0.749
(0.691‑0.823)
0.912
(0.839‑1.00)
1.17
(1.07‑1.28)
1.39
(1.27‑1.52)
1.71
(1.56‑1.87)
2.00
(1.81‑2.18)
2.32
(2.08‑2.53)
2.67
(2.38‑2.91)
3.21
(2.82‑3.50)
3.68
(3.20‑4.02)
6-hr 0.466
(0.430‑0.514)
0.568
(0.524‑0.626)
0.728
(0.668‑0.801)
0.867
(0.793‑0.951)
1.07
(0.976‑1.18)
1.26
(1.14‑1.37)
1.46
(1.31‑1.60)
1.69
(1.50‑1.85)
2.04
(1.79‑2.23)
2.35
(2.03‑2.58)
12-hr 0.272
(0.248‑0.301)
0.331
(0.302‑0.366)
0.427
(0.389‑0.472)
0.511
(0.463‑0.563)
0.637
(0.573‑0.702)
0.751
(0.671‑0.824)
0.878
(0.778‑0.964)
1.02
(0.897‑1.12)
1.25
(1.08‑1.37)
1.45
(1.23‑1.59)
24-hr 0.161
(0.146‑0.179)
0.195
(0.178‑0.218)
0.253
(0.229‑0.282)
0.303
(0.274‑0.337)
0.380
(0.341‑0.423)
0.449
(0.399‑0.499)
0.528
(0.463‑0.587)
0.617
(0.534‑0.687)
0.756
(0.640‑0.847)
0.879
(0.731‑0.989)
2-day 0.095
(0.087‑0.106)
0.115
(0.105‑0.128)
0.148
(0.135‑0.164)
0.176
(0.160‑0.196)
0.220
(0.197‑0.244)
0.258
(0.230‑0.287)
0.301
(0.265‑0.336)
0.350
(0.304‑0.392)
0.425
(0.361‑0.478)
0.490
(0.409‑0.556)
3-day 0.068
(0.062‑0.075)
0.082
(0.075‑0.091)
0.104
(0.095‑0.116)
0.124
(0.113‑0.137)
0.153
(0.138‑0.170)
0.179
(0.159‑0.198)
0.207
(0.183‑0.231)
0.239
(0.208‑0.268)
0.288
(0.246‑0.324)
0.331
(0.278‑0.375)
4-day 0.054
(0.050‑0.060)
0.065
(0.060‑0.072)
0.083
(0.075‑0.092)
0.098
(0.089‑0.108)
0.120
(0.108‑0.133)
0.139
(0.124‑0.154)
0.160
(0.142‑0.178)
0.184
(0.161‑0.205)
0.220
(0.189‑0.248)
0.252
(0.213‑0.285)
7-day 0.036
(0.033‑0.039)
0.043
(0.040‑0.047)
0.054
(0.050‑0.059)
0.063
(0.058‑0.069)
0.077
(0.070‑0.084)
0.088
(0.080‑0.096)
0.101
(0.090‑0.110)
0.114
(0.101‑0.126)
0.134
(0.117‑0.149)
0.151
(0.130‑0.169)
10-day 0.028
(0.026‑0.031)
0.034
(0.031‑0.037)
0.042
(0.039‑0.046)
0.049
(0.045‑0.053)
0.058
(0.054‑0.064)
0.067
(0.061‑0.073)
0.076
(0.068‑0.083)
0.085
(0.076‑0.093)
0.099
(0.087‑0.110)
0.111
(0.096‑0.124)
20-day 0.019
(0.018‑0.020)
0.022
(0.021‑0.024)
0.027
(0.025‑0.030)
0.031
(0.029‑0.034)
0.037
(0.034‑0.040)
0.042
(0.039‑0.045)
0.047
(0.043‑0.051)
0.052
(0.047‑0.057)
0.060
(0.053‑0.066)
0.066
(0.058‑0.073)
30-day 0.015
(0.014‑0.016)
0.018
(0.017‑0.020)
0.022
(0.021‑0.023)
0.025
(0.023‑0.027)
0.029
(0.027‑0.031)
0.032
(0.030‑0.035)
0.036
(0.033‑0.038)
0.039
(0.036‑0.042)
0.044
(0.040‑0.048)
0.048
(0.043‑0.053)
45-day 0.013
(0.012‑0.014)
0.015
(0.014‑0.016)
0.018
(0.017‑0.019)
0.020
(0.019‑0.022)
0.023
(0.022‑0.025)
0.026
(0.024‑0.028)
0.029
(0.026‑0.031)
0.031
(0.029‑0.033)
0.035
(0.032‑0.038)
0.038
(0.034‑0.041)
60-day 0.012
(0.011‑0.012)
0.014
(0.013‑0.014)
0.016
(0.015‑0.017)
0.018
(0.017‑0.019)
0.020
(0.019‑0.021)
0.022
(0.021‑0.024)
0.024
(0.022‑0.026)
0.026
(0.024‑0.028)
0.029
(0.026‑0.031)
0.031
(0.028‑0.033)
1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).
Numbers 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 notchecked 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.
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PF graphical
3/8/2021 Precipitation Frequency Data Server
https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=34.2835&lon=-77.8076&data=intensity&units=english&series=pds 2/4
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Maps & aerials
Small scale terrain
3/8/2021 Precipitation Frequency Data Server
https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=34.2835&lon=-77.8076&data=intensity&units=english&series=pds 3/4
Large scale terrain
Large scale map
Large scale aerial
+
–
3km
2mi
+
–
100km
60mi
+
–
100km
60mi
3/8/2021 Precipitation Frequency Data Server
https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=34.2835&lon=-77.8076&data=intensity&units=english&series=pds 4/4
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US Department of Commerce
National Oceanic and Atmospheric Administration
National Weather Service
National Water Center
1325 East West Highway
Silver Spring, MD 20910
Questions?: HDSC.Questions@noaa.gov
Disclaimer
+
–
100km
60mi
CHARLOTTE-MECKLENBURG STORM WATER DESIGN MANUAL
2-18
Table 2-12 Runoff Curve Numbers1
Curve numbers for ------------------------------Cover description -------------------------------- -----hydrologic soil group----- Average percent
Cover type and hydrologic condition impervious area 2/ A B C D
Fully developed urban areas (vegetation established)
Open space (lawns, parks, golf courses, cemeteries, etc.) 3/: Poor condition (grass cover < 50%) ............................ 68 79 86 89 Fair condition (grass cover 50% to 75%) .................... 49 69 79 84
Good condition (grass cover > 75%) ........................... 39 61 74 80 Impervious areas: Paved parking lots, roofs, driveways, etc.
(excluding right-of-way) ..................................... 98 98 98 98 Streets and roads: Paved; curbs and storm sewers (excluding right-of-way) ....................................................... 98 98 98 98 Paved; open ditches (including right-of-way) .... 83 89 92 93 Gravel (including right-of-way) .......................... 76 85 89 91 Dirt (including right-of-way) .............................. 72 82 87 89 Urban districts:
Commercial and business ............................................ 85 89 92 94 95 Industrial ..................................................................... 72 81 88 91 93 Residential districts by average lot size:
1/8 acre or less (town houses) ..................................... 65 77 85 90 92 1/4 acre ........................................................................ 38 61 75 83 87 1/3 acre ........................................................................ 30 57 72 81 86
1/2 acre ........................................................................ 25 54 70 80 85 1 acre ........................................................................... 20 51 68 79 84 2 acres ......................................................................... 12 46 65 77 82
Agricultural Lands Pasture, grassland or range (continuous for age for grazing)4
Poor hydrologic condition ........................................... 68 79 86 89 Fair hydrologic condition ............................................ 49 69 79 84 Good hydrologic condition ......................................... 39 61 74 80
Woods Poor hydrologic condition ........................................... 45 66 77 83 Fair hydrologic condition ............................................ 36 60 73 79 Good hydrologic condition ......................................... 30 55 70 77 Developing urban areas Newly graded areas (pervious areas only, no vegetation) ........................... 77 86 91 94
1 Average runoff condition, and Ia = 0.2S.
2 The average percent impervious area shown was used to develop the composite CN’s. Other assumptions are as follows: impervious areas area directly connected to the drainage system, impervious areas have a CN of 98, and pervious areas are considered equivalent to open space in good hydrologic condition.
3 CN’s shown are equivalent to those of pasture. Composite CN’s may be computed for other combinations of open space cover type.
4 Poor: Forest litter, small trees, and brush are destroyed by heavy grazing or regular burning.
Fair: Woods are grazed but not burned, and some forest litter covers the soil.
Good: Woods are protected from grazing, and litter and brush adequately cover the soil.
Source: 210-VI-TR-55, Second Edition, June 1986
MARKET STREET - U.S. HWY. NO. 17
100' WIDTH PUBLIC R/W
55
53525152
51 5353
55
54
52
51
51
53
51
50
5050
52
51
52
4951
5
25
3
4948
48
51
525454
5454 5354545252515151514849485252525250495353
50Tc>Tc >Tc>Tc>Tc>Tc>Tc>Tc>Tc>Tc>Tc>Tc>Tc
>Tc
>Tc
>Tc>Tc>Tc>Tc>Tc>Tc>Tc>Tc
>
Tc
>
Tc
>
Tc
>Tc>Tc >Tc>Tc>Tc>Tc >
N
S
W E
E.E.I.PRE-DEVELOPMENTDRAINAGE AREA MAPNO.DATEBYISSUESCALEDESIGNED BYCHECKED BYJOB NUMBERDRAWN BYDATEFIRM LICENSE # C-08732013A VAN BUREN AVENUEINDIAN TRAIL, NC 28079(704) 882-4222WWW.EAGLEONLINE.NETEAGLE ENGINEERINGAS SHOWN09/23/20207057BUY QUICK FOOD MART7650 MARKET ST.WILMINGTON, NCKHALID SALEH3811 COTTONWOOD DRIVEDURHAM, NC 27705JPCJLRJPC0311 21
112-15-20SAPADDRESSED NEW HANOVER COUNTY COMMENTS203-11-21SAPADDRESSED NEW HANOVER COUNTY COMMENTS00 20'40'
20
EX. GRAVEL LOT
EX. GRAVEL LOT
EX. BUILDING
EX. BUILDING
EX. BUILDING
EX. BUILDING
EX. BUILDING
EX. STORAGE
CONTAINERS
EX. PARKING LOT
POINT OF ANALYSIS
A - B
60' SHEET FLOW @ 3.8%
(SHORT GRASS)
A
B
C
D
B - C
115' SHALLOW CONC.
FLOW @ 1.0%
(PAVED)
C - D
250' SHALLOW CONC.
FLOW @ 1.1%
(UNPAVED)
TOTAL PRE-DEV.
DRAINAGE AREA 1
(94,039 SQ. FT.
OR 2.16 AC)
MARKET STREET - U.S. HWY. NO. 17
100' WIDTH PUBLIC R/W
55
53525152
51 5353
55
54
52
51
51
53
51
50
5050
52
51
52
4951
5
25
3
4948
48
51
525454
5454 5354545252515151514849485252525250495353
50
CB-102
CB-101 15" RCPCB-202
MH-201
1
5
"
RC
P
FES-200
15" RCP Tc>Tc>Tc>Tc>Tc>Tc>Tc>Tc>15" RCP
FES-100
N
S
W E
E.E.I.POST-DEVELOPMENTDRAINAGE AREA MAPNO.DATEBYISSUESCALEDESIGNED BYCHECKED BYJOB NUMBERDRAWN BYDATEFIRM LICENSE # C-08732013A VAN BUREN AVENUEINDIAN TRAIL, NC 28079(704) 882-4222WWW.EAGLEONLINE.NETEAGLE ENGINEERINGAS SHOWN09/23/20207057BUY QUICK FOOD MART7650 MARKET ST.WILMINGTON, NCKHALID SALEH3811 COTTONWOOD DRIVEDURHAM, NC 27705JPCJLRJPC0311 21
112-15-20SAPADDRESSED NEW HANOVER COUNTY COMMENTS203-11-21SAPADDRESSED NEW HANOVER COUNTY COMMENTS00 20'40'
20
EX. BUILDING
EX. STORAGE
CONTAINERS
EX. PARKING LOT
POINT OF ANALYSIS
TOTAL POST-DEV.
DRAINAGE AREA 1
(41,545 SQ. FT.
OR 0.95 AC)
TOTAL POST-DEV. BYPASS
DRAINAGE AREA
(52,494 SQ. FT. OR 1.21 AC)
A - B
60' SHEET FLOW @ 2.5%
(SHORT GRASS)
B - C
95' SHALLOW CONC.
FLOW @ 1.0%
(UNPAVED)
A
B
C
PROJECT:CLIENT:
PROJ. #:DATE:
PHASE:DESIGN BY:
Water Quality Volume (WQV) based upon the
first inch of rainfall.
Drainage Area (A) =41,545 Ft2 0.95 ac
New Impervious Area ** =7,569 Ft2 0.17 ac
Impervious Fraction (IA) =0.18 18 %
0.21
741 ft3
Rainfall Depth (RD) =1.0 in.
Runoff Coefficient (RV) =0.21 unitless
Watershed Area (A) =0.95 ac.
Permanent Pool Elev. =49.00
Temp. Ponding (WQV) Elev. =50.00 Elev Area (sf) Vol (cf) Total (cf)
Temp. Ponding Depth =1.00 OK (Perm. Pool)49.00 2,990 00
WQV Provided =3,176 ft3 50.00 3,362 3,176 3,176
Surface Area Required =741 ft2
Surface Area Provided =3,362 ft3
Forebay Area Req'd (min.) =336 ft2 (10‐15% Surface)
Area Provided:354 ft0 Elev Area (sf) Vol (cf) Total (cf)
Design Percentage 11%OK (Entrance)47.00 37 00
Forebay Entrance Depth =2.0 OK (Exit)48.00 220 129 129
Forebay Exit Elevation =48.0 48.50 354 144 272
Deep Pool Area Req'd (min.) =168 ft2 (5‐15% Surface)
Area Provided:481 ft0 Elev Area (sf) Vol (cf) Total (cf)
Design Percentage 14%OK 47.00 142 00
Deep Pool Depth =2.0 OK 48.00 354 248 248
48.50 481 209 457
Shallow Water Area Req'd =1,177 ft2 (35‐45% Surface)
Area Provided:1,326 ft0 Elev Area (sf) Vol (cf) Total (cf)
Design Percentage 39%OK 48.50 835 00
Shallow Water Depth =0.5 OK 49.00 2,161 749 749
Inundation Area Req'd =1,177 ft2 (35‐45% Surface)
Area Provided:1,200 ft0 Elev Area (sf) Vol (cf) Total (cf)
Design Percentage 36%OK 49.00 2,162 00
Inundation Zone Depth =1.0 OK 50.00 3,362 2,762 2,762
Forebay Volume Calculation
Deep Pools Volume Calculation
Shallow Water Volume Calculation
Inundation Zone Volume Calculation
Stormwater Wetlands ‐ NCDEQ BMP Manual
Calculate Water Quality Volume
Length, Width (Area), Depth, Geometry
Dv = 3630*RD*RV*A =
Rv = 0.05+0.9*IA =
Design Volume (Water Quality Volume "WQv")
Runoff Coefficient
WQV Volume Calculation
** The new impervious area is
qualified as the net increase in
impervious from existing conditions.
Wetland A SAP Indian Trail, NC 28079
Stormwater Wetlands
Buy Quick Food Mart Khalid Saleh
12/9/2020 2013A Van Buren Avenue7057
EEI Project No. 6700
Wet Detention Pond Page 1
Orifice diameter =1 in.
Orifice inv. Elev. =49.00
Orifice Equation:Q = CD A (2g(HO/3))0.5
2‐day Avg Discharge (Q2av) =0.0184 cfs (max.)2.48
5‐day Avg Discharge (Q5av) =0.0074 cfs (min.)OK
Average Discharge (Q) =0.0148 cfs (provided)
Discharge Coefficient (CD) =0.60 HO =
X‐sect area of orifice (A) =0.0055 ft2
Accel. due to gravity (g) =32.2 ft/sec2
Avg. driving head (HO) =0.3194 ft
WQV Outlet Device
Driving Head (ft), measured from the centroid
of the orifice area to the water surface
Note: Use HO/3 to compute drawdown to reflect
the fact that head is decreasing as drawdown
occurs
Days to Discharge WQV
EEI Project No. 6700
Wet Detention Pond Page 2
Hydraflow Table of Contents Stormwater Wetlands.gpw
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Watershed Model Schematic...................................................................................... 1
Hydrograph Return Period Recap............................................................................. 2
2 - Year
Summary Report......................................................................................................................... 3
Hydrograph Reports................................................................................................................... 4
Hydrograph No. 1, SCS Runoff, PRE-DEV.............................................................................. 4
TR-55 Tc Worksheet............................................................................................................ 5
Hydrograph No. 3, SCS Runoff, POST-DEV............................................................................ 6
Hydrograph No. 4, Reservoir, Stormwater Wetland................................................................. 7
Pond Report - Stormwater Wetland..................................................................................... 8
Hydrograph No. 5, SCS Runoff, POST-DEV-BYPASS............................................................. 9
TR-55 Tc Worksheet.......................................................................................................... 10
Hydrograph No. 6, Combine, POST-DEV-TOTAL.................................................................. 11
10 - Year
Summary Report....................................................................................................................... 12
Hydrograph Reports................................................................................................................. 13
Hydrograph No. 1, SCS Runoff, PRE-DEV............................................................................ 13
Hydrograph No. 3, SCS Runoff, POST-DEV.......................................................................... 14
Hydrograph No. 4, Reservoir, Stormwater Wetland............................................................... 15
Hydrograph No. 5, SCS Runoff, POST-DEV-BYPASS........................................................... 16
Hydrograph No. 6, Combine, POST-DEV-TOTAL.................................................................. 17
25 - Year
Summary Report....................................................................................................................... 18
Hydrograph Reports................................................................................................................. 19
Hydrograph No. 1, SCS Runoff, PRE-DEV............................................................................ 19
Hydrograph No. 3, SCS Runoff, POST-DEV.......................................................................... 20
Hydrograph No. 4, Reservoir, Stormwater Wetland............................................................... 21
Hydrograph No. 5, SCS Runoff, POST-DEV-BYPASS........................................................... 22
Hydrograph No. 6, Combine, POST-DEV-TOTAL.................................................................. 23
100 - Year
Summary Report....................................................................................................................... 24
Hydrograph Reports................................................................................................................. 25
Hydrograph No. 1, SCS Runoff, PRE-DEV............................................................................ 25
Hydrograph No. 3, SCS Runoff, POST-DEV.......................................................................... 26
Hydrograph No. 4, Reservoir, Stormwater Wetland............................................................... 27
Hydrograph No. 5, SCS Runoff, POST-DEV-BYPASS........................................................... 28
Hydrograph No. 6, Combine, POST-DEV-TOTAL.................................................................. 29
IDF Report.................................................................................................................. 30
13
4
5
6
1
Watershed Model Schematic Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021
Project: Stormwater Wetlands.gpw Wednesday, 03 / 10 / 2021
Hydrograph Return Period Recap
2
Hyd. Hydrograph Inflow Peak Outflow (cfs) Hydrograph
No. type hyd(s)Description
(origin) 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr
1 SCS Runoff ------ ------- 5.643 ------- ------- 12.44 17.77 ------- 28.31 PRE-DEV
3 SCS Runoff ------ ------- 5.612 ------- ------- 9.086 11.55 ------- 16.25 POST-DEV
4 Reservoir 3 ------- 2.322 ------- ------- 4.767 9.325 ------- 15.71 Stormwater Wetland
5 SCS Runoff ------ ------- 3.109 ------- ------- 6.976 10.07 ------- 16.22 POST-DEV-BYPASS
6 Combine 4, 5 ------- 5.017 ------- ------- 11.33 17.62 ------- 31.56 POST-DEV-TOTAL
Proj. file: Stormwater Wetlands.gpw Wednesday, 03 / 10 / 2021
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021
Hydrograph Summary Report
3
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 5.643 2 720 12,979 ------ ------ ------ PRE-DEV
3 SCS Runoff 5.612 2 716 12,212 ------ ------ ------ POST-DEV
4 Reservoir 2.322 2 722 9,467 3 50.88 5,852 Stormwater Wetland
5 SCS Runoff 3.109 2 718 6,232 ------ ------ ------ POST-DEV-BYPASS
6 Combine 5.017 2 718 15,699 4, 5 ------ ------ POST-DEV-TOTAL
Stormwater Wetlands.gpw Return Period: 2 Year Wednesday, 03 / 10 / 2021
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Hyd. No. 1
PRE-DEV
Hydrograph type = SCS Runoff Peak discharge = 5.643 cfs
Storm frequency = 2 yrs Time to peak = 12.00 hrs
Time interval = 2 min Hyd. volume = 12,979 cuft
Drainage area = 2.160 ac Curve number = 68*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 7.60 min
Total precip. = 4.68 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
* Composite (Area/CN) = [(0.590 x 98) + (0.450 x 76) + (1.120 x 49)] / 2.160
4
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
5.00 5.00
6.00 6.00
Q (cfs)
Time (hrs)
PRE-DEV
Hyd. No. 1 -- 2 Year
Hyd No. 1
TR55 Tc Worksheet 5
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021
Hyd. No. 1
PRE-DEV
Description A B C Totals
Sheet Flow
Manning's n-value = 0.150 0.011 0.011
Flow length (ft) = 60.0 0.0 0.0
Two-year 24-hr precip. (in) = 4.68 0.00 0.00
Land slope (%) = 3.80 0.00 0.00
Travel Time (min) = 4.16 + 0.00 + 0.00 = 4.16
Shallow Concentrated Flow
Flow length (ft) = 115.00 250.00 0.00
Watercourse slope (%) = 1.00 1.10 0.00
Surface description = Paved Unpaved Paved
Average velocity (ft/s) =2.03 1.69 0.00
Travel Time (min) = 0.94 + 2.46 + 0.00 = 3.41
Channel Flow
X sectional flow area (sqft) = 0.00 0.00 0.00
Wetted perimeter (ft) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.015 0.015 0.015
Velocity (ft/s) =0.00
0.00
0.00
Flow length (ft) ({0})0.0 0.0 0.0
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Total Travel Time, Tc .............................................................................. 7.60 min
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Hyd. No. 3
POST-DEV
Hydrograph type = SCS Runoff Peak discharge = 5.612 cfs
Storm frequency = 2 yrs Time to peak = 11.93 hrs
Time interval = 2 min Hyd. volume = 12,212 cuft
Drainage area = 0.950 ac Curve number = 92*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 4.68 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
* Composite (Area/CN) = [(0.850 x 98) + (0.100 x 39)] / 0.950
6
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
5.00 5.00
6.00 6.00
Q (cfs)
Time (hrs)
POST-DEV
Hyd. No. 3 -- 2 Year
Hyd No. 3
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Hyd. No. 4
Stormwater Wetland
Hydrograph type = Reservoir Peak discharge = 2.322 cfs
Storm frequency = 2 yrs Time to peak = 12.03 hrs
Time interval = 2 min Hyd. volume = 9,467 cuft
Inflow hyd. No. = 3 - POST-DEV Max. Elevation = 50.88 ft
Reservoir name = Stormwater Wetland Max. Storage = 5,852 cuft
Storage Indication method used.
7
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
5.00 5.00
6.00 6.00
Q (cfs)
Time (hrs)
Stormwater Wetland
Hyd. No. 4 -- 2 Year
Hyd No. 4 Hyd No. 3 Total storage used = 5,852 cuft
Pond Report 8
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Pond No. 1 - Stormwater Wetland
Pond Data
Contours -User-defined contour areas. Conic method used for volume calculation. Begining Elevation = 49.00 ft
Stage / Storage Table
Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft) Total storage (cuft)
0.00 49.00 2,162 0 0
1.00 50.00 3,362 2,740 2,740
2.00 51.00 3,755 3,556 6,296
3.00 52.00 4,167 3,959 10,255
3.50 52.50 4,382 2,137 12,392
Culvert / Orifice Structures Weir Structures
[A] [B] [C] [PrfRsr] [A] [B] [C] [D]
Rise (in)= 10.00 0.00 0.00 0.00
Span (in)= 10.00 0.00 0.00 0.00
No. Barrels = 2 000
Invert El. (ft)= 50.00 0.00 0.00 0.00
Length (ft)= 25.00 0.00 0.00 0.00
Slope (%)= 0.50 0.00 0.00 n/a
N-Value = .013 .013 .013 n/a
Orifice Coeff.= 0.60 0.60 0.60 0.60
Multi-Stage = n/a NoNoNo
Crest Len (ft)= 20.00 0.00 0.00 0.00
Crest El. (ft)= 51.50 0.00 0.00 0.00
Weir Coeff.= 3.33 3.33 3.33 3.33
Weir Type = Rect --- --- ---
Multi-Stage = No No No No
Exfil.(in/hr)= 0.000 (by Wet area)
TW Elev. (ft)= 0.00
Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s).
0.00 8.00 16.00 24.00 32.00 40.00 48.00 56.00 64.00 72.00 80.00
Stage (ft)
0.00 49.00
1.00 50.00
2.00 51.00
3.00 52.00
4.00 53.00
Elev (ft)
Discharge (cfs)
Stage / Discharge
Total Q
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Hyd. No. 5
POST-DEV-BYPASS
Hydrograph type = SCS Runoff Peak discharge = 3.109 cfs
Storm frequency = 2 yrs Time to peak = 11.97 hrs
Time interval = 2 min Hyd. volume = 6,232 cuft
Drainage area = 1.210 ac Curve number = 66*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 5.90 min
Total precip. = 4.68 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
* Composite (Area/CN) = [(0.430 x 98) + (0.780 x 49)] / 1.210
9
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
Q (cfs)
Time (hrs)
POST-DEV-BYPASS
Hyd. No. 5 -- 2 Year
Hyd No. 5
TR55 Tc Worksheet 10
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021
Hyd. No. 5
POST-DEV-BYPASS
Description A B C Totals
Sheet Flow
Manning's n-value = 0.150 0.011 0.011
Flow length (ft) = 60.0 0.0 0.0
Two-year 24-hr precip. (in) = 4.68 0.00 0.00
Land slope (%) = 2.50 0.00 0.00
Travel Time (min) = 4.92 + 0.00 + 0.00 = 4.92
Shallow Concentrated Flow
Flow length (ft) = 95.00 0.00 0.00
Watercourse slope (%) = 1.00 0.00 0.00
Surface description = Unpaved Paved Paved
Average velocity (ft/s) =1.61 0.00 0.00
Travel Time (min) = 0.98 + 0.00 + 0.00 = 0.98
Channel Flow
X sectional flow area (sqft) = 0.00 0.00 0.00
Wetted perimeter (ft) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.015 0.015 0.015
Velocity (ft/s) =0.00
0.00
0.00
Flow length (ft) ({0})0.0 0.0 0.0
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Total Travel Time, Tc .............................................................................. 5.90 min
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Hyd. No. 6
POST-DEV-TOTAL
Hydrograph type = Combine Peak discharge = 5.017 cfs
Storm frequency = 2 yrs Time to peak = 11.97 hrs
Time interval = 2 min Hyd. volume = 15,699 cuft
Inflow hyds. = 4, 5 Contrib. drain. area = 1.210 ac
11
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
5.00 5.00
6.00 6.00
Q (cfs)
Time (hrs)
POST-DEV-TOTAL
Hyd. No. 6 -- 2 Year
Hyd No. 6 Hyd No. 4 Hyd No. 5
Hydrograph Summary Report
12
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 12.44 2 718 28,461 ------ ------ ------ PRE-DEV
3 SCS Runoff 9.086 2 716 20,437 ------ ------ ------ POST-DEV
4 Reservoir 4.767 2 722 17,693 3 51.45 8,065 Stormwater Wetland
5 SCS Runoff 6.976 2 718 14,074 ------ ------ ------ POST-DEV-BYPASS
6 Combine 11.33 2 718 31,767 4, 5 ------ ------ POST-DEV-TOTAL
Stormwater Wetlands.gpw Return Period: 10 Year Wednesday, 03 / 10 / 2021
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Hyd. No. 1
PRE-DEV
Hydrograph type = SCS Runoff Peak discharge = 12.44 cfs
Storm frequency = 10 yrs Time to peak = 11.97 hrs
Time interval = 2 min Hyd. volume = 28,461 cuft
Drainage area = 2.160 ac Curve number = 68*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 7.60 min
Total precip. = 7.27 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
* Composite (Area/CN) = [(0.590 x 98) + (0.450 x 76) + (1.120 x 49)] / 2.160
13
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Q (cfs)
0.00 0.00
2.00 2.00
4.00 4.00
6.00 6.00
8.00 8.00
10.00 10.00
12.00 12.00
14.00 14.00
Q (cfs)
Time (hrs)
PRE-DEV
Hyd. No. 1 -- 10 Year
Hyd No. 1
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Hyd. No. 3
POST-DEV
Hydrograph type = SCS Runoff Peak discharge = 9.086 cfs
Storm frequency = 10 yrs Time to peak = 11.93 hrs
Time interval = 2 min Hyd. volume = 20,437 cuft
Drainage area = 0.950 ac Curve number = 92*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 7.27 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
* Composite (Area/CN) = [(0.850 x 98) + (0.100 x 39)] / 0.950
14
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0
Q (cfs)
0.00 0.00
2.00 2.00
4.00 4.00
6.00 6.00
8.00 8.00
10.00 10.00
Q (cfs)
Time (hrs)
POST-DEV
Hyd. No. 3 -- 10 Year
Hyd No. 3
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Hyd. No. 4
Stormwater Wetland
Hydrograph type = Reservoir Peak discharge = 4.767 cfs
Storm frequency = 10 yrs Time to peak = 12.03 hrs
Time interval = 2 min Hyd. volume = 17,693 cuft
Inflow hyd. No. = 3 - POST-DEV Max. Elevation = 51.45 ft
Reservoir name = Stormwater Wetland Max. Storage = 8,065 cuft
Storage Indication method used.
15
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Q (cfs)
0.00 0.00
2.00 2.00
4.00 4.00
6.00 6.00
8.00 8.00
10.00 10.00
Q (cfs)
Time (hrs)
Stormwater Wetland
Hyd. No. 4 -- 10 Year
Hyd No. 4 Hyd No. 3 Total storage used = 8,065 cuft
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Hyd. No. 5
POST-DEV-BYPASS
Hydrograph type = SCS Runoff Peak discharge = 6.976 cfs
Storm frequency = 10 yrs Time to peak = 11.97 hrs
Time interval = 2 min Hyd. volume = 14,074 cuft
Drainage area = 1.210 ac Curve number = 66*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 5.90 min
Total precip. = 7.27 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
* Composite (Area/CN) = [(0.430 x 98) + (0.780 x 49)] / 1.210
16
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
5.00 5.00
6.00 6.00
7.00 7.00
Q (cfs)
Time (hrs)
POST-DEV-BYPASS
Hyd. No. 5 -- 10 Year
Hyd No. 5
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Hyd. No. 6
POST-DEV-TOTAL
Hydrograph type = Combine Peak discharge = 11.33 cfs
Storm frequency = 10 yrs Time to peak = 11.97 hrs
Time interval = 2 min Hyd. volume = 31,767 cuft
Inflow hyds. = 4, 5 Contrib. drain. area = 1.210 ac
17
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Q (cfs)
0.00 0.00
2.00 2.00
4.00 4.00
6.00 6.00
8.00 8.00
10.00 10.00
12.00 12.00
Q (cfs)
Time (hrs)
POST-DEV-TOTAL
Hyd. No. 6 -- 10 Year
Hyd No. 6 Hyd No. 4 Hyd No. 5
Hydrograph Summary Report
18
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 17.77 2 718 40,775 ------ ------ ------ PRE-DEV
3 SCS Runoff 11.55 2 716 26,392 ------ ------ ------ POST-DEV
4 Reservoir 9.325 2 720 23,648 3 51.65 8,861 Stormwater Wetland
5 SCS Runoff 10.07 2 716 20,387 ------ ------ ------ POST-DEV-BYPASS
6 Combine 17.62 2 718 44,035 4, 5 ------ ------ POST-DEV-TOTAL
Stormwater Wetlands.gpw Return Period: 25 Year Wednesday, 03 / 10 / 2021
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Hyd. No. 1
PRE-DEV
Hydrograph type = SCS Runoff Peak discharge = 17.77 cfs
Storm frequency = 25 yrs Time to peak = 11.97 hrs
Time interval = 2 min Hyd. volume = 40,775 cuft
Drainage area = 2.160 ac Curve number = 68*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 7.60 min
Total precip. = 9.13 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
* Composite (Area/CN) = [(0.590 x 98) + (0.450 x 76) + (1.120 x 49)] / 2.160
19
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Q (cfs)
0.00 0.00
3.00 3.00
6.00 6.00
9.00 9.00
12.00 12.00
15.00 15.00
18.00 18.00
Q (cfs)
Time (hrs)
PRE-DEV
Hyd. No. 1 -- 25 Year
Hyd No. 1
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Hyd. No. 3
POST-DEV
Hydrograph type = SCS Runoff Peak discharge = 11.55 cfs
Storm frequency = 25 yrs Time to peak = 11.93 hrs
Time interval = 2 min Hyd. volume = 26,392 cuft
Drainage area = 0.950 ac Curve number = 92*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 9.13 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
* Composite (Area/CN) = [(0.850 x 98) + (0.100 x 39)] / 0.950
20
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0
Q (cfs)
0.00 0.00
2.00 2.00
4.00 4.00
6.00 6.00
8.00 8.00
10.00 10.00
12.00 12.00
Q (cfs)
Time (hrs)
POST-DEV
Hyd. No. 3 -- 25 Year
Hyd No. 3
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Hyd. No. 4
Stormwater Wetland
Hydrograph type = Reservoir Peak discharge = 9.325 cfs
Storm frequency = 25 yrs Time to peak = 12.00 hrs
Time interval = 2 min Hyd. volume = 23,648 cuft
Inflow hyd. No. = 3 - POST-DEV Max. Elevation = 51.65 ft
Reservoir name = Stormwater Wetland Max. Storage = 8,861 cuft
Storage Indication method used.
21
0 2 4 6 8 10 12 14 16 18 20 22 24
Q (cfs)
0.00 0.00
2.00 2.00
4.00 4.00
6.00 6.00
8.00 8.00
10.00 10.00
12.00 12.00
Q (cfs)
Time (hrs)
Stormwater Wetland
Hyd. No. 4 -- 25 Year
Hyd No. 4 Hyd No. 3 Total storage used = 8,861 cuft
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Hyd. No. 5
POST-DEV-BYPASS
Hydrograph type = SCS Runoff Peak discharge = 10.07 cfs
Storm frequency = 25 yrs Time to peak = 11.93 hrs
Time interval = 2 min Hyd. volume = 20,387 cuft
Drainage area = 1.210 ac Curve number = 66*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 5.90 min
Total precip. = 9.13 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
* Composite (Area/CN) = [(0.430 x 98) + (0.780 x 49)] / 1.210
22
0 2 4 6 8 10 12 14 16 18 20 22 24
Q (cfs)
0.00 0.00
2.00 2.00
4.00 4.00
6.00 6.00
8.00 8.00
10.00 10.00
12.00 12.00
Q (cfs)
Time (hrs)
POST-DEV-BYPASS
Hyd. No. 5 -- 25 Year
Hyd No. 5
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Hyd. No. 6
POST-DEV-TOTAL
Hydrograph type = Combine Peak discharge = 17.62 cfs
Storm frequency = 25 yrs Time to peak = 11.97 hrs
Time interval = 2 min Hyd. volume = 44,035 cuft
Inflow hyds. = 4, 5 Contrib. drain. area = 1.210 ac
23
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Q (cfs)
0.00 0.00
3.00 3.00
6.00 6.00
9.00 9.00
12.00 12.00
15.00 15.00
18.00 18.00
Q (cfs)
Time (hrs)
POST-DEV-TOTAL
Hyd. No. 6 -- 25 Year
Hyd No. 6 Hyd No. 4 Hyd No. 5
Hydrograph Summary Report
24
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 28.31 2 718 65,847 ------ ------ ------ PRE-DEV
3 SCS Runoff 16.25 2 716 37,868 ------ ------ ------ POST-DEV
4 Reservoir 15.71 2 718 35,123 3 51.78 9,385 Stormwater Wetland
5 SCS Runoff 16.22 2 716 33,337 ------ ------ ------ POST-DEV-BYPASS
6 Combine 31.56 2 718 68,460 4, 5 ------ ------ POST-DEV-TOTAL
Stormwater Wetlands.gpw Return Period: 100 Year Wednesday, 03 / 10 / 2021
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Hyd. No. 1
PRE-DEV
Hydrograph type = SCS Runoff Peak discharge = 28.31 cfs
Storm frequency = 100 yrs Time to peak = 11.97 hrs
Time interval = 2 min Hyd. volume = 65,847 cuft
Drainage area = 2.160 ac Curve number = 68*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 7.60 min
Total precip. = 12.70 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
* Composite (Area/CN) = [(0.590 x 98) + (0.450 x 76) + (1.120 x 49)] / 2.160
25
0 2 4 6 8 10 12 14 16 18 20 22 24
Q (cfs)
0.00 0.00
5.00 5.00
10.00 10.00
15.00 15.00
20.00 20.00
25.00 25.00
30.00 30.00
Q (cfs)
Time (hrs)
PRE-DEV
Hyd. No. 1 -- 100 Year
Hyd No. 1
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Hyd. No. 3
POST-DEV
Hydrograph type = SCS Runoff Peak discharge = 16.25 cfs
Storm frequency = 100 yrs Time to peak = 11.93 hrs
Time interval = 2 min Hyd. volume = 37,868 cuft
Drainage area = 0.950 ac Curve number = 92*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 12.70 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
* Composite (Area/CN) = [(0.850 x 98) + (0.100 x 39)] / 0.950
26
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0
Q (cfs)
0.00 0.00
3.00 3.00
6.00 6.00
9.00 9.00
12.00 12.00
15.00 15.00
18.00 18.00
Q (cfs)
Time (hrs)
POST-DEV
Hyd. No. 3 -- 100 Year
Hyd No. 3
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Hyd. No. 4
Stormwater Wetland
Hydrograph type = Reservoir Peak discharge = 15.71 cfs
Storm frequency = 100 yrs Time to peak = 11.97 hrs
Time interval = 2 min Hyd. volume = 35,123 cuft
Inflow hyd. No. = 3 - POST-DEV Max. Elevation = 51.78 ft
Reservoir name = Stormwater Wetland Max. Storage = 9,385 cuft
Storage Indication method used.
27
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0
Q (cfs)
0.00 0.00
3.00 3.00
6.00 6.00
9.00 9.00
12.00 12.00
15.00 15.00
18.00 18.00
Q (cfs)
Time (hrs)
Stormwater Wetland
Hyd. No. 4 -- 100 Year
Hyd No. 4 Hyd No. 3 Total storage used = 9,385 cuft
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Hyd. No. 5
POST-DEV-BYPASS
Hydrograph type = SCS Runoff Peak discharge = 16.22 cfs
Storm frequency = 100 yrs Time to peak = 11.93 hrs
Time interval = 2 min Hyd. volume = 33,337 cuft
Drainage area = 1.210 ac Curve number = 66*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 5.90 min
Total precip. = 12.70 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
* Composite (Area/CN) = [(0.430 x 98) + (0.780 x 49)] / 1.210
28
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0
Q (cfs)
0.00 0.00
3.00 3.00
6.00 6.00
9.00 9.00
12.00 12.00
15.00 15.00
18.00 18.00
Q (cfs)
Time (hrs)
POST-DEV-BYPASS
Hyd. No. 5 -- 100 Year
Hyd No. 5
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Hyd. No. 6
POST-DEV-TOTAL
Hydrograph type = Combine Peak discharge = 31.56 cfs
Storm frequency = 100 yrs Time to peak = 11.97 hrs
Time interval = 2 min Hyd. volume = 68,460 cuft
Inflow hyds. = 4, 5 Contrib. drain. area = 1.210 ac
29
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0
Q (cfs)
0.00 0.00
5.00 5.00
10.00 10.00
15.00 15.00
20.00 20.00
25.00 25.00
30.00 30.00
35.00 35.00
Q (cfs)
Time (hrs)
POST-DEV-TOTAL
Hyd. No. 6 -- 100 Year
Hyd No. 6 Hyd No. 4 Hyd No. 5
Hydraflow Rainfall Report 30
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Wednesday, 03 / 10 / 2021
Return Intensity-Duration-Frequency Equation Coefficients (FHA)
Period
(Yrs) B D E (N/A)
1 76.3783 12.3000 0.8781 --------
2 91.7027 12.7000 0.8745 --------
3 0.0000 0.0000 0.0000 --------
5 98.3565 12.9000 0.8409 --------
10 95.4203 12.4000 0.8018 --------
25 86.9079 11.3000 0.7442 --------
50 76.4692 9.8000 0.6909 --------
100 73.7168 9.3000 0.6581 --------
File name: New Hanover County NC.IDF
Intensity = B / (Tc + D)^E
Return Intensity Values (in/hr)
Period(Yrs)5 min1015202530354045505560
1 6.25 5.00 4.19 3.61 3.18 2.85 2.58 2.37 2.18 2.03 1.90 1.78
2 7.43 5.98 5.02 4.34 3.84 3.44 3.12 2.86 2.64 2.46 2.30 2.16
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 8.70 7.07 5.99 5.21 4.63 4.17 3.80 3.50 3.24 3.02 2.83 2.67
10 9.66 7.89 6.71 5.87 5.23 4.73 4.33 3.99 3.71 3.47 3.26 3.08
25 10.89 8.92 7.63 6.70 6.00 5.45 5.01 4.64 4.33 4.06 3.83 3.63
50 11.88 9.72 8.32 7.33 6.58 6.00 5.53 5.14 4.81 4.53 4.28 4.07
100 12.80 10.51 9.03 7.98 7.20 6.58 6.08 5.67 5.32 5.02 4.76 4.53
Tc = time in minutes. Values may exceed 60.
Rainfall Precipitation Table (in)
Precip. file name: X:\Lib\IDF CURVES\New Hanover County NC.pcp
Storm
Distribution 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr
SCS 24-hour 3.86 4.68 0.00 4.44 7.27 9.13 10.80 12.70
SCS 6-Hr 0.00 0.00 0.00 3.16 0.00 0.00 0.00 0.00
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
CB-102 CB-101 0.38 0% 100% 0.95 9.67 3.44 3.44 0.013 0.50% 12313.5153.7 4.58 75% 0.65 1.12 4.18 0.55 0.49 49.84 49.22 52.77 1.43 RCP -CB-101 FES-100 0.08 0% 100% 0.95 9.67 0.75 4.19 0.013 0.50% 314.5153.7 4.57 92% 0.74 1.14 4.24 0.02 0.01 49.02 49.00 52.56 2.04 RCP -CB-202 MH-201 0.24 0% 100% 0.95 9.67 2.20 2.20 0.013 0.50% 12611.4153.7 4.56 48% 0.47 0.94 3.49 0.57 0.60 49.92 49.29 53.02 1.60 RCP -MH-201 FES-200 #N/A - - - 9.67 0.00 2.20 0.013 0.50% 1711.4153.7 4.56 48% 0.47 0.94 3.49 0.08 0.08 49.09 49.00 52.49 1.91 RCP -Pipe Input/Cover CalculationsOriginal Date:Location Storm RunoffInlet AreasPipe Sizing CalculationsStorm Network 100From StructureTo Structure (acres)Composite Runoff Coeff. CcVfull (fps)Size (in)Dtheo (in)Pipe Length (ft)Pipe Capacity Q-full (cfs)Q-full (%)Inlet Discharge Q (cfs)Percent Pervious (%)Percent Impervios (%)I (in/hr) Material nBuy Quick Food MartDescriptionPM:SAPRevision Date:DB:SAP3/10/21N/AProject Number:7057v/V-fulld/dm ratioPipe Slope (%)Combined Discharge Qpipe (cfs)Actual Vpipe (fps)Pipe Inv. OutPipe Inv. InStructure Rim Elevation (Flowline)Depth Of Cover (Based on Rim)Pipe MaterialPipe Material ClassPipe Time (min) - Full Cond.Actual Pipe Time (min)
BASIN 2
Project Client
Project #Date
Designation Designer
Total Drainage Area 0.95 Acres 41,505 Square Feet
Total Disturbed Area 0.95 Acres 41,505 Square Feet
C 0.50
TC 5 Minutes
I10 9.67 Inches per Hour
Q10 4.61 CFS Contour Area Volume Net Volume
49 2,660 00
Required Volume 1,715 Cubic Feet (1800 CF*DA)50 3,362 00
Required Surface Area 1,497 Square Feet (325 SF*Q10)51 3,755 3,559 3,559
51.5 3,956 1,928 5,486
Provided Volume 5,486 Cubic Feet OK 52 4,167 2,031 7,517
Provided Surface Area 3,956 Square Feet OK 52.5 4,382 2,137 9,654
Length 98 Feet
Width 44 Feet Q10 4.61 CFS
H 1 Feet
Spillway Elevation 51.5 *Provides 1 Foot Freeboard C 3.367
Surface Area at Spillway 3,956 L 1.37 Feet
Top of Berm Elevation 52.5
Spillway Length 20 Feet OK Days to Drain 3 Days
Head over Spillway 1 Feet Skimmer Size 2 Inches
Weir Coefficient 3.367 *Cipoletti Weir Orifice Radius 0.7 Inches
Max Flow 67.3 CFS OK Orifice Diameter 1.4 Inches
2013A Van Buren Ave.
SKIMMER BASIN #1
Buy Quick Food Mart Khalid Saleh
7057 3/10/2021
Spillway & Skimmer Design
SB‐1 PH‐2 SAP Indian Trail, NC 28079
NC Erosion and Sediment Control Planning and Design Manual
Minimum Spillway Design
EAGLE, ENGINEERING, INC.
2013 VAN BUREN AVENUE, STE A
INDIAN TRAIL, NORTH CAROLINA 28079
Project:
Structure:
DO =15 in.d50 (6"min.)=6 in.
Q10 =4.19 cfs dmax =9.00 in.
3DO =3.75 ft. th= 13.50 in.
La =8 ft.
W =9.25 ft.
Rip Rap Apron Design
Buy Quick Food Mart
FES‐100
NCDENR Erosion and Sediment Control Planning and Design Manual
EEI Project No. 5858
Rip Rap Apron Design
Project:
Structure:
DO =15 in.d50 (6"min.)=6 in.
Q10 =2.2 cfs dmax =9.00 in.
3DO =3.75 ft. th= 13.50 in.
La =8 ft.
W =9.25 ft.
Rip Rap Apron Design
Buy Quick Food Mart
FES‐200
NCDENR Erosion and Sediment Control Planning and Design Manual
EEI Project No. 5858
Rip Rap Apron Design
Project:
Structure:
DO =20 in.d50 (6"min.)=6 in.
Q10 =2.2 cfs dmax =9.00 in.
3DO =5 ft. th= 13.50 in.
La =8 ft.
W =9.67 ft.
Rip Rap Apron Design
Buy Quick Food Mart
Outfall
NCDENR Erosion and Sediment Control Planning and Design Manual
EEI Project No. 5858
Rip Rap Apron Design