SW3191204_SW Report_20200626

SEAL
E
NGI N E E RPROFESSIO
N
ALNOR T H CAROLI
NA047366
STEVE
R. F A R M A R TINO6/26/2

2

Table of Contents

General Project Description ................................................................................................................. 3

Stormwater Management Analysis and BMP Calculations .................................................................. 4

Appendix ............................................................................................................................................... 5
HydroCAD Output ..........................................................................................................................
Stormsewer Output .......................................................................................................................

3

General Project Description/Stormwater Management

GENERAL PROJECT OVERVIEW AND EXISTING CONDITIONS

The subject site is situated at the north-western corner of Old Statesville Highway and Brick
Yard Road, in Union County. The project site currently contains an abandoned farmstead and
consists of approximately 10.40 acres. The proposed project will include approximately 210
multifamily residential units spread throughout 6 buildings, as well as a clubhouse, community
pool, and all associated infrastructure.

The Site drains to four Point of Interests (POIs), the first two (POI-1 and POI-2) drain to the
north and into the heart of the Yadkin Pee Dee watershed, and the second two (POI-3 and POI-
4) are the sum of waters being conveyed across Old Charlotte Highway via two existing
culverts.

The site is majority pasture with woods along the northern and south-eastern property line,
with Type B and Type D soils across the site with average existing slopes of 1% to 3%. There is
currently no stormwater measure provided on the site. There is no off-site area examined in
this analysis.

STORMWATER REQUIREMENTS AND DESIGN OVERVIEW

This project is located in the Yadkin Pee Dee watershed per the NCDENR Watershed Interactive
Mapper and is upstream of Stewart Creek. This project is classified as a high-density project
because the largest drainage area has greater than 12% built upon area.

Stormwater quality treatment systems shall treat the runoff generated from the first inch of
rainfall.

All structural stormwater treatment systems used to meet these requirements shall be designed
to have a minimum of 85% average annual removal for total suspended solids and 70%
average annual removal for total phosphorus.

General engineering design criteria shall be accordance with 15 A NCAC 2H. 1008(c) in the
design manual.

The peak discharge is attenuated for both the 2-year, 24-hr storm and the 25-year, 24-hr storm
events. The 100-year, 24-hr storm event has been analyzed to provide 1’ of freeboard to the
top of berm.

To meet the above requirements, two wet ponds located at the Northwest and Northeast
corners of the subject property will be used. These ponds are linked hydraulically through an
equilibrium pipe. The pipe has 0% slope, has an invert equal to the permanent pool elevation,
and will be water tight.

4

STORMSEWER DESIGN

Stormwater run-off from the site will be directed to the existing outfall locations via a system of
storm sewer pipes. The storm sewer was modeled in Hydraflow Storm Sewers Extension for
Autodesk AutoCAD Civil 3D. The storm sewer pipes were modeled to ensure their adequate
capacity with a minimum slope of 0.5% to promote flushing of the pipes.

Stormwater Management and BMP Calculations

PRE VS. POST ANALYSIS PEAK ATTENUATION

See table below for final flow calculations for the pre and post conditions. It should be noted
that time of concentration is accounted for in the summation of the combined peak discharge
values.

Four POI’s we’re analyzed as part of the Stormwater Design for this project. POI-1 and POI-2
discharge to the north of the site through the wet pond system, and POI-3 discharge across Old
Charlotte Highway via the two existing culverts. See below for a summary of both POI’s pre-
versus post- drainage values.

DRAINAGE AREA
2-YR 24
HR(cfs)
25-YR 24
HR(cfs)
POI-1
Existing Conditions 10.50 25.30
Developed Conditions 6.90 23.09
POI-2
Existing Conditions 2.79 6.66
Developed Conditions 0.00 0.00
POI-3
Existing Conditions 3.38 6.92
Developed Conditions 2.41 4.79
POI-4
Existing Conditions 5.70 12.03
Developed Conditions 3.78 7.08

All associated calculations have been provided within the Appendix section of this report.

WATER QUALITY
Water quality treatment of the 1” water quality volume, is also provided within the proposed
above-ground wet detention pond and is to be detained between 2-5 days (See appendix for
calculations).

5

Appendix
Hydrologic Soil Group—Union County, North Carolina
(Arca Heights - USDA Soil Survey)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
11/13/2019
Page 1 of 438772903877340387739038774403877490387754038775903877290387734038773903877440387749038775403877590533510533560533610533660533710533760533810533860533910533960534010
533510 533560 533610 533660 533710 533760 533810 533860 533910 533960 534010
35° 2' 26'' N 80° 37' 57'' W35° 2' 26'' N80° 37' 37'' W35° 2' 15'' N
80° 37' 57'' W35° 2' 15'' N
80° 37' 37'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 17N WGS84
0 100 200 400 600
Feet
0 35 70 140 210
Meters
Map Scale: 1:2,380 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
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Union County, North Carolina
Survey Area Data: Version 19, Sep 16, 2019
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Jul 18, 2011—Nov
25, 2017
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—Union County, North Carolina
(Arca Heights - USDA Soil Survey)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
11/13/2019
Page 2 of 4
Hydrologic Soil Group
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
CmB Cid channery silt loam, 1
to 5 percent slopes
D 2.3 21.9%
GsB Goldston-Badin
complex, 2 to 8
percent slopes
D 7.4 69.4%
TaB Tarrus gravelly silt loam,
2 to 8 percent slopes
B 0.9 8.6%
Totals for Area of Interest 10.6 100.0%
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—Union County, North Carolina Arca Heights - USDA Soil Survey
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
11/13/2019
Page 3 of 4
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Hydrologic Soil Group—Union County, North Carolina Arca Heights - USDA Soil Survey
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
11/13/2019
Page 4 of 4
3/2/2020 Precipitation Frequency Data Server
https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=35.0390&lon=-80.6299&data=intensity&units=english&series=pds 1/4
NOAA Atlas 14, Volume 2, Version 3
Location name: Monroe, North Carolina, USA*
Latitude: 35.039°, Longitude: -80.6299°
Elevation: 664.54 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 5.03
(4.63‑5.46)
5.94
(5.46‑6.47)
6.90
(6.34‑7.50)
7.60
(6.96‑8.24)
8.39
(7.66‑9.10)
8.94
(8.11‑9.68)
9.43
(8.53‑10.2)
9.88
(8.88‑10.7)
10.4
(9.25‑11.3)
10.7
(9.50‑11.7)
10-min 4.01
(3.70‑4.36)
4.75
(4.37‑5.17)
5.52
(5.07‑6.01)
6.07
(5.56‑6.59)
6.68
(6.10‑7.24)
7.12
(6.46‑7.71)
7.49
(6.77‑8.12)
7.83
(7.04‑8.49)
8.21
(7.32‑8.92)
8.46
(7.48‑9.21)
15-min 3.35
(3.08‑3.64)
3.98
(3.66‑4.34)
4.66
(4.28‑5.07)
5.12
(4.69‑5.56)
5.64
(5.15‑6.12)
6.00
(5.46‑6.51)
6.32
(5.71‑6.84)
6.59
(5.92‑7.14)
6.89
(6.14‑7.49)
7.08
(6.26‑7.70)
30-min 2.29
(2.11‑2.49)
2.75
(2.53‑2.99)
3.31
(3.04‑3.60)
3.71
(3.40‑4.03)
4.18
(3.82‑4.53)
4.52
(4.11‑4.90)
4.84
(4.37‑5.24)
5.13
(4.61‑5.56)
5.48
(4.89‑5.96)
5.73
(5.07‑6.24)
60-min 1.43
(1.32‑1.55)
1.73
(1.59‑1.88)
2.12
(1.95‑2.31)
2.42
(2.21‑2.62)
2.78
(2.54‑3.02)
3.06
(2.78‑3.32)
3.33
(3.01‑3.61)
3.60
(3.23‑3.90)
3.93
(3.51‑4.27)
4.18
(3.70‑4.55)
2-hr 0.826
(0.758‑0.904)
1.00
(0.916‑1.10)
1.24
(1.13‑1.36)
1.42
(1.30‑1.55)
1.66
(1.51‑1.81)
1.84
(1.66‑2.00)
2.02
(1.81‑2.19)
2.19
(1.96‑2.39)
2.42
(2.14‑2.64)
2.60
(2.28‑2.84)
3-hr 0.585
(0.535‑0.643)
0.706
(0.646‑0.777)
0.881
(0.805‑0.968)
1.02
(0.926‑1.11)
1.20
(1.09‑1.31)
1.34
(1.21‑1.47)
1.49
(1.33‑1.62)
1.64
(1.45‑1.79)
1.84
(1.61‑2.01)
2.00
(1.74‑2.19)
6-hr 0.353
(0.323‑0.387)
0.425
(0.390‑0.467)
0.531
(0.486‑0.582)
0.614
(0.560‑0.672)
0.727
(0.659‑0.792)
0.817
(0.736‑0.889)
0.909
(0.813‑0.989)
1.00
(0.889‑1.09)
1.14
(0.991‑1.23)
1.24
(1.07‑1.35)
12-hr 0.207
(0.190‑0.227)
0.250
(0.230‑0.275)
0.314
(0.288‑0.345)
0.365
(0.333‑0.400)
0.435
(0.394‑0.475)
0.492
(0.442‑0.537)
0.551
(0.491‑0.600)
0.613
(0.540‑0.667)
0.701
(0.607‑0.761)
0.771
(0.659‑0.838)
24-hr 0.123
(0.114‑0.134)
0.149
(0.138‑0.161)
0.187
(0.173‑0.203)
0.217
(0.200‑0.236)
0.259
(0.238‑0.281)
0.293
(0.268‑0.318)
0.328
(0.299‑0.356)
0.365
(0.331‑0.396)
0.416
(0.375‑0.452)
0.457
(0.410‑0.498)
2-day 0.073
(0.067‑0.079)
0.087
(0.081‑0.095)
0.109
(0.101‑0.118)
0.126
(0.116‑0.137)
0.150
(0.138‑0.163)
0.169
(0.155‑0.183)
0.189
(0.172‑0.205)
0.210
(0.190‑0.228)
0.238
(0.215‑0.260)
0.261
(0.234‑0.286)
3-day 0.051
(0.048‑0.055)
0.062
(0.057‑0.067)
0.076
(0.071‑0.083)
0.088
(0.082‑0.095)
0.105
(0.096‑0.113)
0.118
(0.108‑0.127)
0.131
(0.120‑0.142)
0.146
(0.133‑0.158)
0.165
(0.150‑0.180)
0.181
(0.163‑0.198)
4-day 0.041
(0.038‑0.044)
0.049
(0.045‑0.053)
0.060
(0.056‑0.065)
0.069
(0.064‑0.075)
0.082
(0.076‑0.088)
0.092
(0.085‑0.100)
0.103
(0.094‑0.111)
0.114
(0.104‑0.123)
0.129
(0.117‑0.140)
0.141
(0.128‑0.154)
7-day 0.027
(0.025‑0.029)
0.032
(0.030‑0.034)
0.039
(0.036‑0.042)
0.045
(0.042‑0.048)
0.052
(0.049‑0.056)
0.059
(0.054‑0.063)
0.065
(0.060‑0.070)
0.072
(0.066‑0.077)
0.081
(0.074‑0.087)
0.089
(0.081‑0.096)
10-day 0.022
(0.020‑0.023)
0.026
(0.024‑0.027)
0.031
(0.029‑0.033)
0.035
(0.033‑0.037)
0.041
(0.038‑0.043)
0.045
(0.042‑0.048)
0.049
(0.046‑0.053)
0.054
(0.050‑0.058)
0.060
(0.056‑0.065)
0.065
(0.060‑0.070)
20-day 0.014
(0.014‑0.015)
0.017
(0.016‑0.018)
0.020
(0.019‑0.021)
0.023
(0.021‑0.024)
0.026
(0.024‑0.028)
0.029
(0.027‑0.030)
0.031
(0.029‑0.033)
0.034
(0.031‑0.036)
0.037
(0.035‑0.040)
0.040
(0.037‑0.043)
30-day 0.012
(0.011‑0.012)
0.014
(0.013‑0.015)
0.016
(0.015‑0.017)
0.018
(0.017‑0.019)
0.020
(0.019‑0.021)
0.022
(0.021‑0.023)
0.024
(0.022‑0.025)
0.026
(0.024‑0.027)
0.028
(0.026‑0.030)
0.030
(0.028‑0.032)
45-day 0.010
(0.009‑0.010)
0.012
(0.011‑0.012)
0.013
(0.013‑0.014)
0.015
(0.014‑0.015)
0.016
(0.015‑0.017)
0.018
(0.017‑0.018)
0.019
(0.018‑0.020)
0.020
(0.019‑0.021)
0.022
(0.020‑0.023)
0.023
(0.021‑0.024)
60-day 0.009
(0.008‑0.009)
0.010
(0.010‑0.011)
0.012
(0.011‑0.012)
0.013
(0.012‑0.013)
0.014
(0.013‑0.015)
0.015
(0.014‑0.016)
0.016
(0.015‑0.017)
0.017
(0.016‑0.018)
0.018
(0.017‑0.019)
0.019
(0.018‑0.020)
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 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
3/2/2020 Precipitation Frequency Data Server
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Maps & aerials
Small scale terrain
3/2/2020 Precipitation Frequency Data Server
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Large scale terrain
Large scale map
Large scale aerial
+
–
3km
2mi
+
–
100km
60mi
+
–
100km
60mi
3/2/2020 Precipitation Frequency Data Server
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National Oceanic and Atmospheric Administration
National Weather Service
National Water Center
1325 East West Highway
Silver Spring, MD 20910
Questions?: [e-mail]
Disclaimer
+
–
100km
60mi
DESIGN:
GIVEN:
5.11 Ac.
60%
5 FEET
60%
SA/DA = 1.49 % = 0.0149 (60% SA/DA)
SA REQUIRED = 5.11 Ac. X 0.0149
= 0.08 Ac.
= 3,317 SF
THE VOLUME FOR THE 1" STORM EVENT CAN BE CALCULATED AS:
Design Rainfall = 1 Inch
Drainage Area = 5.11 Acres
Rv = 0.05 + 0.9(I)
I = Percent Impervious = 60%
Rv = 0.59 in./in.
V1 =0.252 acre-feet = 10,994
ft3
Pond Height above Orifice = 660.00 feet
Orifice Invert Elevation = 659.00 feet
Orifice Diameter (D) = 2.00 inches = 0.17 feet
Orifice Area (a) = 0.0218 square feet
Gravitational Constant (g) = 32.2 ft/sec2
Head (H) = 0.92 feet
Driving Head (HO) =0.306 feet
Discharge Coefficient (CD) =0.6
Drawdown rate (Q) = 0.058 cfs
Drawdown volume (ft3) (total both ponds) 19,971
Time (t) = 343,933 seconds = 3.98 days
Note:
The above calculation is based on the orifice equation where:
1) SA/DA RATIO:
AVERAGE POOL DEPTH =
PERCENT IMPERVIOUS =
2) TEMPORARY WATER QUALITY POOL REQUIREMENTS
PROVIDE VOLUME TO DETAIN THE 1" STORM EVENT ABOVE THE ELEVATION
ALLOCATED AS A PERMANENT POOL
3) Pond Drawdown Time
V1 = (Design Rainfall)(Rv)(Drainage Area)
Note: Oriface set at 660.00 due to total volume required of 19,253 ft3
being met at this elevation between both ponds
WET POND #1 WEST ARKA HEIGHTS (MONROE, NC)
WATER QUALITY TO MEET 85% TSS REMOVAL
DRAINAGE AREA TO FACILITY =
LAND USE = Apartments
PERCENT IMPERVIOUS =
3/2/2020 1:33 PM Page 1 of 1
DESIGN:
GIVEN:
3.84 Ac.
66%
4 FEET
66%
SA/DA = 2.09 % = 0.0209 (70% SA/DA)
SA REQUIRED = 3.84 Ac. X 0.0209
= 0.08 Ac.
= 3,496 SF
THE VOLUME FOR THE 1" STORM EVENT CAN BE CALCULATED AS:
Design Rainfall = 1 Inch
Drainage Area = 3.84 Acres
Rv = 0.05 + 0.9(I)
I = Percent Impervious = 66%
Rv = 0.64 in./in.
V1 =0.206 acre-feet = 8,977
ft3
Pond Height above Orifice = 660.00 feet
Orifice Invert Elevation = 659.00 feet
Orifice Diameter (D) = 2.00 inches = 0.17 feet
Orifice Area (a) = 0.0218 square feet
Gravitational Constant (g) = 32.2
ft/sec2
Head (H) = 0.92 feet
Driving Head (HO) =0.306 feet
Discharge Coefficient (C D) =0.6
Drawdown rate (Q) = 0.058 cfs
Drawdown volume (ft3) (total both ponds) 19,971
Time (t) = 343,933 seconds = 3.98 days
Note:
The above calculation is based on the orifice equation where:
WET POND #1 EAST ARKA HEIGHTS (MONROE, NC)
WATER QUALITY TO MEET 90% TSS REMOVAL
DRAINAGE AREA TO FACILITY =
LAND USE = Apartments
PERCENT IMPERVIOUS =
3) Pond Drawdown Time
1) SA/DA RATIO:
AVERAGE POOL DEPTH =
Note: Oriface set at 660.00 due to total volume required of 19,253 ft3
being met at this elevation between both ponds
PERCENT IMPERVIOUS =
2) TEMPORARY WATER QUALITY POOL REQUIREMENTS
PROVIDE VOLUME TO DETAIN THE 1" STORM EVENT ABOVE THE ELEVATION
ALLOCATED AS A PERMANENT POOL
V1 = (Design Rainfall)(Rv)(Drainage Area)
3/2/2020 1:33 PM Page 1 of 1
Elev West Area (sf) West Inc Storage (cf) West Total Storage (cf) East Area (sf) East Inc Storage (cf) East Total Storage (cf) Total Storage (cf)659 8,330 0 0 11,279 0 0 0660 9,595 8,963 8,963 12,679 11,979 11,979 20,942661 10,920 10,258 19,220 14,134 13,407 25,386 44,606662 12,297 11,609 30,829 15,646 14,890 40,276 71,104663 13,733 13,015 43,844 17,215 16,431 56,706 100,550664 15,225 14,479 58,323 18,840 18,028 74,734 133,056Elev West Area (sf) West Inc Storage (cf) West Total Storage (cf) East Area (sf) East Inc Storage (cf) East Total Storage (cf) Total Storage (cf)653 1,791 0 0 0 0 0 0654 2,297 2,044 2,044 4,441 0 0 2,044655 2,837 2,567 4,611 5,048 4,745 4,745 9,356656 3,409 3,123 7,734 5,681 5,365 10,109 17,843657 4,011 3,710 11,444 6,341 6,011 16,120 27,564658 4,644 4,328 15,772 7,027 6,684 22,804 38,576659 6,476 5,560 21,332 8,936 7,982 30,786 52,117Elev West Area (sf) West Inc Storage (cf) West Total Storage (cf) East Area (sf) East Inc Storage (cf) East Total Storage (cf) Total Storage (cf)654 0 0 0 300 0 0 0655 0 0 0 494 397 397 397656 620 310 310 735 615 1,012 1,322657 858 739 1,049 1,028 882 1,893 2,942658 1,125 992 2,041 1,371 1,200 3,093 5,133659 1,853 1,489 3,530 2,343 1,857 4,950 8,479Wet Pond #1 Design Wet Pond D Treatment VolumeWet Pond D Permanent Pool Volume - Main PoolWet Pond D Permanent Pool - Forebay3/2/2020 3:08 PMPage 1 of 1
MDC Criteria Requirement Provided Meets Criteria (Y/N)
MDC 1 : Main Pool Surface Area and Volume
SA = 6,813 SF
V = 19,971 CF
SA = 15,412 SF
V = 52,118 CF Y
MDC 2 : Main Pool Depth 3-8'4.5'Y
MDC 3 : Sediment Storage 6"6"Y
MDC 4 : Location of Inlet(s) and Outlet No Short Circuiting No Short Circuiting Y
MDC 5 : Forebay 15-20% Main Pool Volume 16.30%Y
MDC 6 : Vegetated Shelf 6' at 6:1 6' at 6:1 Y
MDC 7 : Drawdown Time 2-5 days 3.98 days Y
MDC 8 : Protection of Receiving Stream Minimize Hydraulic Impacts Detain peak flows Y
MDC 9 : Fountains N/A N/A N/A
MDC 10 : Trash Rack Provide trash rack Provided Y
MDC 11 : Vegetation Three Species Three Species Y
Arka Heights Wet Pond MDC Criteria (Entire Pond)
* Values provided are summation or weighted average of both portions of the pond
1S
Pre DA 1
2S
Pre DA 2
3S
Pre DA-3
4S
Pre DA-4
5S
Post DA-1
6S
Post DA-2
7S
Post DA-3
8S
Post DA-4
9P
Wet Pond 1 East
10P
Wet Pond 1 West
15P
Wet Pond 1 East
Permanent Pool
16P
Wet Pond 1 West
Permanent Pool
15L
Post DA-1
16L
Post DA-2
Routing Diagram for NCC182110 - Arka Heights - 200421
Prepared by Bohler Engineering, Printed 6/26/2020
HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Subcat Reach Pond Link
NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 2HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Area Listing (all nodes)
Area
(acres)
CN Description
(subcatchment-numbers)
1.620 61 >75% Grass cover, Good, HSG B (5S, 6S)
2.609 80 >75% Grass cover, Good, HSG D (3S, 5S, 6S, 7S, 8S)
1.877 69 Pasture/grassland/range, Fair, HSG B (1S, 2S)
5.791 84 Pasture/grassland/range, Fair, HSG D (1S, 2S, 4S)
0.230 98 Paved parking, HSG A (5S)
0.250 98 Paved parking, HSG B (7S)
6.384 98 Paved parking, HSG D (3S, 4S, 5S, 6S, 8S)
0.720 98 Water Surface, HSG A (5S, 6S)
0.182 60 Woods, Fair, HSG B (1S)
1.137 79 Woods, Fair, HSG D (1S, 2S, 4S)
20.800 85 TOTAL AREA
NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 3HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Soil Listing (all nodes)
Area
(acres)
Soil
Group
Subcatchment
Numbers
0.950 HSG A 5S, 6S
3.929 HSG B 1S, 2S, 5S, 6S, 7S
0.000 HSG C
15.921 HSG D 1S, 2S, 3S, 4S, 5S, 6S, 7S, 8S
0.000 Other
20.800 TOTAL AREA
NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 4HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Ground Covers (all nodes)
HSG-A
(acres)
HSG-B
(acres)
HSG-C
(acres)
HSG-D
(acres)
Other
(acres)
Total
(acres)
Ground
Cover
Subcatchment
Numbers
0.000 1.620 0.000 2.609 0.000 4.229 >75% Grass cover, Good 3S,
5S,
6S,
7S,
8S
0.000 1.877 0.000 5.791 0.000 7.668 Pasture/grassland/range, Fair 1S,
2S,
4S
0.230 0.250 0.000 6.384 0.000 6.864 Paved parking 3S,
4S,
5S,
6S,
7S,
8S
0.720 0.000 0.000 0.000 0.000 0.720 Water Surface 5S,
6S
0.000 0.182 0.000 1.137 0.000 1.319 Woods, Fair 1S,
2S,
4S
0.950 3.929 0.000 15.921 0.000 20.800 TOTAL AREA
NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 5HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Pipe Listing (all nodes)
Line# Node
Number
In-Invert
(feet)
Out-Invert
(feet)
Length
(feet)
Slope
(ft/ft)
n Diam/Width
(inches)
Height
(inches)
Inside-Fill
(inches)
1 9P 659.00 659.00 700.0 0.0000 0.013 18.0 0.0 0.0
2 10P 659.00 658.90 20.0 0.0050 0.011 24.0 0.0 0.0
Type II 24-hr 2-Year Rainfall=3.57"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 6HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Time span=0.00-120.00 hrs, dt=0.05 hrs, 2401 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method
Runoff Area=5.910 ac 0.00% Impervious Runoff Depth=1.62"Subcatchment 1S: Pre DA 1
Flow Length=605' Tc=20.0 min CN=79 Runoff=10.50 cfs 0.798 af
Runoff Area=1.340 ac 0.00% Impervious Runoff Depth=1.62"Subcatchment 2S: Pre DA 2
Flow Length=312' Tc=14.9 min CN=79 Runoff=2.79 cfs 0.181 af
Runoff Area=1.220 ac 41.07% Impervious Runoff Depth=2.25"Subcatchment 3S: Pre DA-3
Flow Length=375' Tc=16.1 min CN=87 Runoff=3.38 cfs 0.228 af
Runoff Area=1.930 ac 10.00% Impervious Runoff Depth=2.08"Subcatchment 4S: Pre DA-4
Flow Length=303' Tc=11.8 min CN=85 Runoff=5.70 cfs 0.334 af
Runoff Area=5.110 ac 66.54% Impervious Runoff Depth=2.33"Subcatchment 5S: Post DA-1
Tc=5.0 min CN=88 Runoff=20.88 cfs 0.993 af
Runoff Area=3.840 ac 76.04% Impervious Runoff Depth=2.61"Subcatchment 6S: Post DA-2
Tc=5.0 min CN=91 Runoff=17.13 cfs 0.834 af
Runoff Area=0.590 ac 42.37% Impervious Runoff Depth=2.33"Subcatchment 7S: Post DA-3
Tc=5.0 min CN=88 Runoff=2.41 cfs 0.115 af
Runoff Area=0.860 ac 37.21% Impervious Runoff Depth=2.25"Subcatchment 8S: Post DA-4
Tc=6.0 min CN=87 Runoff=3.26 cfs 0.161 af
Peak Elev=660.84' Storage=23,159 cf Inflow=17.13 cfs 0.834 afPond 9P: Wet Pond 1 East
Primary=1.62 cfs 0.799 af Secondary=0.00 cfs 0.000 af Outflow=1.62 cfs 0.799 af
Peak Elev=661.02' Storage=19,447 cf Inflow=20.88 cfs 1.792 afPond 10P: Wet Pond 1 West
Primary=6.90 cfs 1.775 af Secondary=0.00 cfs 0.000 af Outflow=6.90 cfs 1.775 af
Peak Elev=0.00' Storage=0 cfPond 15P: Wet Pond 1 East Permanent Pool
Peak Elev=0.00' Storage=0 cfPond 16P: Wet Pond 1 West Permanent Pool
Inflow=6.90 cfs 1.775 afLink 15L: Post DA-1
Primary=6.90 cfs 1.775 af
Inflow=0.00 cfs 0.000 afLink 16L: Post DA-2
Primary=0.00 cfs 0.000 af
Total Runoff Area = 20.800 ac Runoff Volume = 3.645 af Average Runoff Depth = 2.10"
63.54% Pervious = 13.216 ac 36.46% Impervious = 7.584 ac
Type II 24-hr 2-Year Rainfall=3.57"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 7HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 1S: Pre DA 1
Runoff = 10.50 cfs @ 12.13 hrs, Volume= 0.798 af, Depth= 1.62"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 2-Year Rainfall=3.57"
Area (ac) CN Description
0.182 60 Woods, Fair, HSG B
0.565 79 Woods, Fair, HSG D
1.592 69 Pasture/grassland/range, Fair, HSG B
3.571 84 Pasture/grassland/range, Fair, HSG D
5.910 79 Weighted Average
5.910 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
9.7 75 0.0100 0.13 Sheet Flow, Sheet Flow
Grass: Short n= 0.150 P2= 3.57"
10.3 530 0.0150 0.86 Shallow Concentrated Flow, Shallow Concentrated Flow
Short Grass Pasture Kv= 7.0 fps
20.0 605 Total
Subcatchment 1S: Pre DA 1
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)11
10
9
8
7
6
5
4
3
2
1
0
Type II 24-hr
2-Year Rainfall=3.57"
Runoff Area=5.910 ac
Runoff Volume=0.798 af
Runoff Depth=1.62"
Flow Length=605'
Tc=20.0 min
CN=79
10.50 cfs
Type II 24-hr 2-Year Rainfall=3.57"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 8HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 2S: Pre DA 2
Runoff = 2.79 cfs @ 12.07 hrs, Volume= 0.181 af, Depth= 1.62"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 2-Year Rainfall=3.57"
Area (ac) CN Description
0.365 79 Woods, Fair, HSG D
0.285 69 Pasture/grassland/range, Fair, HSG B
0.690 84 Pasture/grassland/range, Fair, HSG D
1.340 79 Weighted Average
1.340 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
9.7 75 0.0100 0.13 Sheet Flow, Sheet Flow
Grass: Short n= 0.150 P2= 3.57"
5.2 237 0.0116 0.75 Shallow Concentrated Flow, Shallow Concentrated Flow
Short Grass Pasture Kv= 7.0 fps
14.9 312 Total
Subcatchment 2S: Pre DA 2
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)3
2
1
0
Type II 24-hr
2-Year Rainfall=3.57"
Runoff Area=1.340 ac
Runoff Volume=0.181 af
Runoff Depth=1.62"
Flow Length=312'
Tc=14.9 min
CN=79
2.79 cfs
Type II 24-hr 2-Year Rainfall=3.57"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 9HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 3S: Pre DA-3
Runoff = 3.38 cfs @ 12.08 hrs, Volume= 0.228 af, Depth= 2.25"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 2-Year Rainfall=3.57"
Area (ac) CN Description
0.501 98 Paved parking, HSG D
0.719 80 >75% Grass cover, Good, HSG D
1.220 87 Weighted Average
0.719 58.93% Pervious Area
0.501 41.07% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
9.7 75 0.0100 0.13 Sheet Flow, Sheet Flow
Grass: Short n= 0.150 P2= 3.57"
6.4 300 0.0125 0.78 Shallow Concentrated Flow, Shallow Concentrated Flow
Short Grass Pasture Kv= 7.0 fps
16.1 375 Total
Subcatchment 3S: Pre DA-3
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)3
2
1
0
Type II 24-hr
2-Year Rainfall=3.57"
Runoff Area=1.220 ac
Runoff Volume=0.228 af
Runoff Depth=2.25"
Flow Length=375'
Tc=16.1 min
CN=87
3.38 cfs
Type II 24-hr 2-Year Rainfall=3.57"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 10HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 4S: Pre DA-4
Runoff = 5.70 cfs @ 12.04 hrs, Volume= 0.334 af, Depth= 2.08"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 2-Year Rainfall=3.57"
Area (ac) CN Description
1.530 84 Pasture/grassland/range, Fair, HSG D
0.207 79 Woods, Fair, HSG D
0.193 98 Paved parking, HSG D
1.930 85 Weighted Average
1.737 90.00% Pervious Area
0.193 10.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
8.7 75 0.0133 0.14 Sheet Flow, Sheet Flow
Grass: Short n= 0.150 P2= 3.57"
3.1 228 0.0305 1.22 Shallow Concentrated Flow, Shallow Concentrated Flow
Short Grass Pasture Kv= 7.0 fps
11.8 303 Total
Subcatchment 4S: Pre DA-4
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)6
5
4
3
2
1
0
Type II 24-hr
2-Year Rainfall=3.57"
Runoff Area=1.930 ac
Runoff Volume=0.334 af
Runoff Depth=2.08"
Flow Length=303'
Tc=11.8 min
CN=85
5.70 cfs
Type II 24-hr 2-Year Rainfall=3.57"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 11HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 5S: Post DA-1
Runoff = 20.88 cfs @ 11.95 hrs, Volume= 0.993 af, Depth= 2.33"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 2-Year Rainfall=3.57"
Area (ac) CN Description
2.850 98 Paved parking, HSG D
1.070 61 >75% Grass cover, Good, HSG B
0.640 80 >75% Grass cover, Good, HSG D
0.320 98 Water Surface, HSG A
0.230 98 Paved parking, HSG A
5.110 88 Weighted Average
1.710 33.46% Pervious Area
3.400 66.54% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry, Direct Entry
Subcatchment 5S: Post DA-1
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Type II 24-hr
2-Year Rainfall=3.57"
Runoff Area=5.110 ac
Runoff Volume=0.993 af
Runoff Depth=2.33"
Tc=5.0 min
CN=88
20.88 cfs
Type II 24-hr 2-Year Rainfall=3.57"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 12HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 6S: Post DA-2
Runoff = 17.13 cfs @ 11.95 hrs, Volume= 0.834 af, Depth= 2.61"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 2-Year Rainfall=3.57"
Area (ac) CN Description
2.520 98 Paved parking, HSG D
0.370 80 >75% Grass cover, Good, HSG D
0.550 61 >75% Grass cover, Good, HSG B
0.400 98 Water Surface, HSG A
3.840 91 Weighted Average
0.920 23.96% Pervious Area
2.920 76.04% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry, Direct Entry
Subcatchment 6S: Post DA-2
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Type II 24-hr
2-Year Rainfall=3.57"
Runoff Area=3.840 ac
Runoff Volume=0.834 af
Runoff Depth=2.61"
Tc=5.0 min
CN=91
17.13 cfs
Type II 24-hr 2-Year Rainfall=3.57"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 13HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 7S: Post DA-3
Runoff = 2.41 cfs @ 11.95 hrs, Volume= 0.115 af, Depth= 2.33"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 2-Year Rainfall=3.57"
Area (ac) CN Description
0.250 98 Paved parking, HSG B
0.340 80 >75% Grass cover, Good, HSG D
0.590 88 Weighted Average
0.340 57.63% Pervious Area
0.250 42.37% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 7S: Post DA-3
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)2
1
0
Type II 24-hr
2-Year Rainfall=3.57"
Runoff Area=0.590 ac
Runoff Volume=0.115 af
Runoff Depth=2.33"
Tc=5.0 min
CN=88
2.41 cfs
Type II 24-hr 2-Year Rainfall=3.57"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 14HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 8S: Post DA-4
Runoff = 3.26 cfs @ 11.97 hrs, Volume= 0.161 af, Depth= 2.25"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 2-Year Rainfall=3.57"
Area (ac) CN Description
0.320 98 Paved parking, HSG D
0.540 80 >75% Grass cover, Good, HSG D
0.860 87 Weighted Average
0.540 62.79% Pervious Area
0.320 37.21% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
6.0 Direct Entry,
Subcatchment 8S: Post DA-4
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)3
2
1
0
Type II 24-hr
2-Year Rainfall=3.57"
Runoff Area=0.860 ac
Runoff Volume=0.161 af
Runoff Depth=2.25"
Tc=6.0 min
CN=87
3.26 cfs
Type II 24-hr 2-Year Rainfall=3.57"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 15HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 9P: Wet Pond 1 East
Inflow Area = 3.840 ac, 76.04% Impervious, Inflow Depth = 2.61" for 2-Year event
Inflow = 17.13 cfs @ 11.95 hrs, Volume= 0.834 af
Outflow = 1.62 cfs @ 12.84 hrs, Volume= 0.799 af, Atten= 91%, Lag= 53.5 min
Primary = 1.62 cfs @ 12.84 hrs, Volume= 0.799 af
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Dyn-Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 660.84' @ 12.50 hrs Surf.Area= 13,899 sf Storage= 23,159 cf
Plug-Flow detention time= 1,026.6 min calculated for 0.799 af (96% of inflow)
Center-of-Mass det. time= 1,003.7 min ( 1,798.1 - 794.4 )
Volume Invert Avail.Storage Storage Description
#1 659.00' 74,701 cf Temporary Pool (Irregular) Listed below (Recalc)
Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area
(feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft)
659.00 11,279 457.0 0 0 11,279
660.00 12,679 475.0 11,972 11,972 12,693
661.00 14,134 495.0 13,400 25,372 14,311
662.00 15,646 513.0 14,884 40,256 15,840
663.00 17,215 532.0 16,424 56,680 17,505
664.00 18,840 551.0 18,021 74,701 19,229
Device Routing Invert Outlet Devices
#1 Primary 659.00'18.0" Round Culvert
L= 700.0' RCP, groove end projecting, Ke= 0.200
Inlet / Outlet Invert= 659.00' / 659.00' S= 0.0000 '/' Cc= 0.900
n= 0.013, Flow Area= 1.77 sf
#2 Secondary 662.90'30.0' long x 10.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=1.66 cfs @ 12.84 hrs HW=660.80' TW=660.63' (Dynamic Tailwater)
1=Culvert (Outlet Controls 1.66 cfs @ 0.99 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=659.00' TW=0.00' (Dynamic Tailwater)
2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Type II 24-hr 2-Year Rainfall=3.57"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 16HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Pond 9P: Wet Pond 1 East
Inflow
Outflow
Primary
Secondary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Inflow Area=3.840 ac
Peak Elev=660.84'
Storage=23,159 cf
17.13 cfs
1.62 cfs
1.62 cfs
0.00 cfs
Type II 24-hr 2-Year Rainfall=3.57"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 17HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 10P: Wet Pond 1 West
Inflow Area = 8.950 ac, 70.61% Impervious, Inflow Depth > 2.40" for 2-Year event
Inflow = 20.88 cfs @ 11.95 hrs, Volume= 1.792 af
Outflow = 6.90 cfs @ 12.08 hrs, Volume= 1.775 af, Atten= 67%, Lag= 7.8 min
Primary = 6.90 cfs @ 12.08 hrs, Volume= 1.775 af
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Dyn-Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 661.02' @ 12.08 hrs Surf.Area= 10,950 sf Storage= 19,447 cf
Plug-Flow detention time= 412.3 min calculated for 1.775 af (99% of inflow)
Center-of-Mass det. time= 361.6 min ( 1,610.3 - 1,248.7 )
Volume Invert Avail.Storage Storage Description
#1 659.00' 58,288 cf Temporary Pool (Irregular) Listed below (Recalc)
Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area
(feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft)
659.00 8,330 413.0 0 0 8,330
660.00 9,595 431.0 8,955 8,955 9,610
661.00 10,920 450.0 10,250 19,205 11,013
662.00 12,297 469.0 11,602 30,807 12,477
663.00 13,733 488.0 13,008 43,815 14,001
664.00 15,225 507.0 14,473 58,288 15,586
Device Routing Invert Outlet Devices
#1 Primary 659.00'24.0" Round RCP_Round 24"
L= 20.0' RCP, groove end projecting, Ke= 0.200
Inlet / Outlet Invert= 659.00' / 658.90' S= 0.0050 '/' Cc= 0.900
n= 0.011 Concrete pipe, straight & clean, Flow Area= 3.14 sf
#2 Device 1 659.00'2.0" Vert. Orifice/Grate C= 0.600
#3 Device 1 660.00'24.0" W x 12.0" H Vert. Orifice/Grate C= 0.600
#4 Device 1 661.00'16.0' long Sharp-Crested Rectangular Weir 1 End Contraction(s)
#5 Secondary 662.50'40.0' long x 10.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=6.82 cfs @ 12.08 hrs HW=661.02' TW=0.00' (Dynamic Tailwater)
1=RCP_Round 24" (Passes 6.82 cfs of 13.74 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.15 cfs @ 6.69 fps)
3=Orifice/Grate (Orifice Controls 6.57 cfs @ 3.28 fps)
4=Sharp-Crested Rectangular Weir (Weir Controls 0.11 cfs @ 0.42 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=659.00' TW=0.00' (Dynamic Tailwater)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Type II 24-hr 2-Year Rainfall=3.57"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 18HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Pond 10P: Wet Pond 1 West
Inflow
Outflow
Primary
Secondary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Inflow Area=8.950 ac
Peak Elev=661.02'
Storage=19,447 cf
20.88 cfs
6.90 cfs
6.90 cfs
0.00 cfs
Type II 24-hr 2-Year Rainfall=3.57"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 19HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 15P: Wet Pond 1 East Permanent Pool
Volume Invert Avail.Storage Storage Description
#1 654.00' 30,754 cf Main Pool (Irregular) Listed below (Recalc)
#2 654.00' 4,912 cf Forebay (Irregular) Listed below (Recalc)
35,666 cf Total Available Storage
Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area
(feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft)
654.00 4,441 296.0 0 0 4,441
655.00 5,048 309.0 4,741 4,741 5,136
656.00 5,681 323.0 5,361 10,103 5,908
657.00 6,341 336.0 6,008 16,111 6,665
658.00 7,027 349.0 6,681 22,792 7,452
659.00 8,936 385.0 7,962 30,754 9,587
Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area
(feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft)
654.00 300 86.0 0 0 300
655.00 494 108.0 393 393 653
656.00 735 133.0 611 1,004 1,148
657.00 1,028 159.0 877 1,881 1,769
658.00 1,371 183.0 1,195 3,076 2,444
659.00 2,343 233.0 1,835 4,912 4,113
Type II 24-hr 2-Year Rainfall=3.57"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 20HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 16P: Wet Pond 1 West Permanent Pool
Volume Invert Avail.Storage Storage Description
#1 653.00' 21,284 cf Main Pool (Irregular) Listed below (Recalc)
#2 656.00' 3,198 cf Forebay (Irregular) Listed below (Recalc)
24,482 cf Total Available Storage
Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area
(feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft)
653.00 1,791 244.0 0 0 1,791
654.00 2,297 261.0 2,039 2,039 2,519
655.00 2,837 278.0 2,562 4,601 3,297
656.00 3,409 293.0 3,119 7,720 4,036
657.00 4,011 308.0 3,706 11,426 4,813
658.00 4,644 324.0 4,324 15,749 5,678
659.00 6,476 298.0 5,535 21,284 7,002
Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area
(feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft)
656.00 620 112.0 0 0 620
657.00 858 126.0 736 736 911
658.00 1,125 141.0 988 1,724 1,256
659.00 1,853 114.0 1,474 3,198 1,819
Type II 24-hr 2-Year Rainfall=3.57"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 21HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Link 15L: Post DA-1
Inflow Area = 8.950 ac, 70.61% Impervious, Inflow Depth > 2.38" for 2-Year event
Inflow = 6.90 cfs @ 12.08 hrs, Volume= 1.775 af
Primary = 6.90 cfs @ 12.08 hrs, Volume= 1.775 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Link 15L: Post DA-1
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)7
6
5
4
3
2
1
0
Inflow Area=8.950 ac
6.90 cfs
6.90 cfs
Type II 24-hr 2-Year Rainfall=3.57"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 22HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Link 16L: Post DA-2
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Link 16L: Post DA-2
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)1
0
0.00 cfs
0.00 cfs
Type II 24-hr 25-Year Rainfall=6.22"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 23HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Time span=0.00-120.00 hrs, dt=0.05 hrs, 2401 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method
Runoff Area=5.910 ac 0.00% Impervious Runoff Depth=3.88"Subcatchment 1S: Pre DA 1
Flow Length=605' Tc=20.0 min CN=79 Runoff=25.30 cfs 1.909 af
Runoff Area=1.340 ac 0.00% Impervious Runoff Depth=3.88"Subcatchment 2S: Pre DA 2
Flow Length=312' Tc=14.9 min CN=79 Runoff=6.66 cfs 0.433 af
Runoff Area=1.220 ac 41.07% Impervious Runoff Depth=4.73"Subcatchment 3S: Pre DA-3
Flow Length=375' Tc=16.1 min CN=87 Runoff=6.92 cfs 0.481 af
Runoff Area=1.930 ac 10.00% Impervious Runoff Depth=4.51"Subcatchment 4S: Pre DA-4
Flow Length=303' Tc=11.8 min CN=85 Runoff=12.03 cfs 0.725 af
Runoff Area=5.110 ac 66.54% Impervious Runoff Depth=4.84"Subcatchment 5S: Post DA-1
Tc=5.0 min CN=88 Runoff=41.51 cfs 2.060 af
Runoff Area=3.840 ac 76.04% Impervious Runoff Depth=5.17"Subcatchment 6S: Post DA-2
Tc=5.0 min CN=91 Runoff=32.51 cfs 1.655 af
Runoff Area=0.590 ac 42.37% Impervious Runoff Depth=4.84"Subcatchment 7S: Post DA-3
Tc=5.0 min CN=88 Runoff=4.79 cfs 0.238 af
Runoff Area=0.860 ac 37.21% Impervious Runoff Depth=4.73"Subcatchment 8S: Post DA-4
Tc=6.0 min CN=87 Runoff=6.61 cfs 0.339 af
Peak Elev=662.26' Storage=44,305 cf Inflow=32.51 cfs 1.655 afPond 9P: Wet Pond 1 East
Primary=4.01 cfs 1.619 af Secondary=0.00 cfs 0.000 af Outflow=4.01 cfs 1.619 af
Peak Elev=662.06' Storage=31,506 cf Inflow=42.78 cfs 3.680 afPond 10P: Wet Pond 1 West
Primary=23.09 cfs 3.662 af Secondary=0.00 cfs 0.000 af Outflow=23.09 cfs 3.662 af
Peak Elev=0.00' Storage=0 cfPond 15P: Wet Pond 1 East Permanent Pool
Peak Elev=0.00' Storage=0 cfPond 16P: Wet Pond 1 West Permanent Pool
Inflow=23.09 cfs 3.662 afLink 15L: Post DA-1
Primary=23.09 cfs 3.662 af
Inflow=0.00 cfs 0.000 afLink 16L: Post DA-2
Primary=0.00 cfs 0.000 af
Total Runoff Area = 20.800 ac Runoff Volume = 7.840 af Average Runoff Depth = 4.52"
63.54% Pervious = 13.216 ac 36.46% Impervious = 7.584 ac
Type II 24-hr 25-Year Rainfall=6.22"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 24HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 1S: Pre DA 1
Runoff = 25.30 cfs @ 12.12 hrs, Volume= 1.909 af, Depth= 3.88"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 25-Year Rainfall=6.22"
Area (ac) CN Description
0.182 60 Woods, Fair, HSG B
0.565 79 Woods, Fair, HSG D
1.592 69 Pasture/grassland/range, Fair, HSG B
3.571 84 Pasture/grassland/range, Fair, HSG D
5.910 79 Weighted Average
5.910 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
9.7 75 0.0100 0.13 Sheet Flow, Sheet Flow
Grass: Short n= 0.150 P2= 3.57"
10.3 530 0.0150 0.86 Shallow Concentrated Flow, Shallow Concentrated Flow
Short Grass Pasture Kv= 7.0 fps
20.0 605 Total
Subcatchment 1S: Pre DA 1
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Type II 24-hr
25-Year Rainfall=6.22"
Runoff Area=5.910 ac
Runoff Volume=1.909 af
Runoff Depth=3.88"
Flow Length=605'
Tc=20.0 min
CN=79
25.30 cfs
Type II 24-hr 25-Year Rainfall=6.22"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 25HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 2S: Pre DA 2
Runoff = 6.66 cfs @ 12.07 hrs, Volume= 0.433 af, Depth= 3.88"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 25-Year Rainfall=6.22"
Area (ac) CN Description
0.365 79 Woods, Fair, HSG D
0.285 69 Pasture/grassland/range, Fair, HSG B
0.690 84 Pasture/grassland/range, Fair, HSG D
1.340 79 Weighted Average
1.340 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
9.7 75 0.0100 0.13 Sheet Flow, Sheet Flow
Grass: Short n= 0.150 P2= 3.57"
5.2 237 0.0116 0.75 Shallow Concentrated Flow, Shallow Concentrated Flow
Short Grass Pasture Kv= 7.0 fps
14.9 312 Total
Subcatchment 2S: Pre DA 2
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)7
6
5
4
3
2
1
0
Type II 24-hr
25-Year Rainfall=6.22"
Runoff Area=1.340 ac
Runoff Volume=0.433 af
Runoff Depth=3.88"
Flow Length=312'
Tc=14.9 min
CN=79
6.66 cfs
Type II 24-hr 25-Year Rainfall=6.22"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 26HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 3S: Pre DA-3
Runoff = 6.92 cfs @ 12.08 hrs, Volume= 0.481 af, Depth= 4.73"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 25-Year Rainfall=6.22"
Area (ac) CN Description
0.501 98 Paved parking, HSG D
0.719 80 >75% Grass cover, Good, HSG D
1.220 87 Weighted Average
0.719 58.93% Pervious Area
0.501 41.07% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
9.7 75 0.0100 0.13 Sheet Flow, Sheet Flow
Grass: Short n= 0.150 P2= 3.57"
6.4 300 0.0125 0.78 Shallow Concentrated Flow, Shallow Concentrated Flow
Short Grass Pasture Kv= 7.0 fps
16.1 375 Total
Subcatchment 3S: Pre DA-3
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)7
6
5
4
3
2
1
0
Type II 24-hr
25-Year Rainfall=6.22"
Runoff Area=1.220 ac
Runoff Volume=0.481 af
Runoff Depth=4.73"
Flow Length=375'
Tc=16.1 min
CN=87
6.92 cfs
Type II 24-hr 25-Year Rainfall=6.22"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 27HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 4S: Pre DA-4
Runoff = 12.03 cfs @ 12.03 hrs, Volume= 0.725 af, Depth= 4.51"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 25-Year Rainfall=6.22"
Area (ac) CN Description
1.530 84 Pasture/grassland/range, Fair, HSG D
0.207 79 Woods, Fair, HSG D
0.193 98 Paved parking, HSG D
1.930 85 Weighted Average
1.737 90.00% Pervious Area
0.193 10.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
8.7 75 0.0133 0.14 Sheet Flow, Sheet Flow
Grass: Short n= 0.150 P2= 3.57"
3.1 228 0.0305 1.22 Shallow Concentrated Flow, Shallow Concentrated Flow
Short Grass Pasture Kv= 7.0 fps
11.8 303 Total
Subcatchment 4S: Pre DA-4
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)13
12
11
10
9
8
7
6
5
4
3
2
1
0
Type II 24-hr
25-Year Rainfall=6.22"
Runoff Area=1.930 ac
Runoff Volume=0.725 af
Runoff Depth=4.51"
Flow Length=303'
Tc=11.8 min
CN=85
12.03 cfs
Type II 24-hr 25-Year Rainfall=6.22"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 28HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 5S: Post DA-1
Runoff = 41.51 cfs @ 11.95 hrs, Volume= 2.060 af, Depth= 4.84"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 25-Year Rainfall=6.22"
Area (ac) CN Description
2.850 98 Paved parking, HSG D
1.070 61 >75% Grass cover, Good, HSG B
0.640 80 >75% Grass cover, Good, HSG D
0.320 98 Water Surface, HSG A
0.230 98 Paved parking, HSG A
5.110 88 Weighted Average
1.710 33.46% Pervious Area
3.400 66.54% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry, Direct Entry
Subcatchment 5S: Post DA-1
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)46
44
42
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Type II 24-hr
25-Year Rainfall=6.22"
Runoff Area=5.110 ac
Runoff Volume=2.060 af
Runoff Depth=4.84"
Tc=5.0 min
CN=88
41.51 cfs
Type II 24-hr 25-Year Rainfall=6.22"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 29HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 6S: Post DA-2
Runoff = 32.51 cfs @ 11.95 hrs, Volume= 1.655 af, Depth= 5.17"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 25-Year Rainfall=6.22"
Area (ac) CN Description
2.520 98 Paved parking, HSG D
0.370 80 >75% Grass cover, Good, HSG D
0.550 61 >75% Grass cover, Good, HSG B
0.400 98 Water Surface, HSG A
3.840 91 Weighted Average
0.920 23.96% Pervious Area
2.920 76.04% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry, Direct Entry
Subcatchment 6S: Post DA-2
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Type II 24-hr
25-Year Rainfall=6.22"
Runoff Area=3.840 ac
Runoff Volume=1.655 af
Runoff Depth=5.17"
Tc=5.0 min
CN=91
32.51 cfs
Type II 24-hr 25-Year Rainfall=6.22"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 30HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 7S: Post DA-3
Runoff = 4.79 cfs @ 11.95 hrs, Volume= 0.238 af, Depth= 4.84"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 25-Year Rainfall=6.22"
Area (ac) CN Description
0.250 98 Paved parking, HSG B
0.340 80 >75% Grass cover, Good, HSG D
0.590 88 Weighted Average
0.340 57.63% Pervious Area
0.250 42.37% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 7S: Post DA-3
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)5
4
3
2
1
0
Type II 24-hr
25-Year Rainfall=6.22"
Runoff Area=0.590 ac
Runoff Volume=0.238 af
Runoff Depth=4.84"
Tc=5.0 min
CN=88
4.79 cfs
Type II 24-hr 25-Year Rainfall=6.22"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 31HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 8S: Post DA-4
Runoff = 6.61 cfs @ 11.96 hrs, Volume= 0.339 af, Depth= 4.73"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 25-Year Rainfall=6.22"
Area (ac) CN Description
0.320 98 Paved parking, HSG D
0.540 80 >75% Grass cover, Good, HSG D
0.860 87 Weighted Average
0.540 62.79% Pervious Area
0.320 37.21% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
6.0 Direct Entry,
Subcatchment 8S: Post DA-4
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)7
6
5
4
3
2
1
0
Type II 24-hr
25-Year Rainfall=6.22"
Runoff Area=0.860 ac
Runoff Volume=0.339 af
Runoff Depth=4.73"
Tc=6.0 min
CN=87
6.61 cfs
Type II 24-hr 25-Year Rainfall=6.22"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 32HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 9P: Wet Pond 1 East
Inflow Area = 3.840 ac, 76.04% Impervious, Inflow Depth = 5.17" for 25-Year event
Inflow = 32.51 cfs @ 11.95 hrs, Volume= 1.655 af
Outflow = 4.01 cfs @ 12.55 hrs, Volume= 1.619 af, Atten= 88%, Lag= 36.2 min
Primary = 4.01 cfs @ 12.55 hrs, Volume= 1.619 af
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Dyn-Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 662.26' @ 12.31 hrs Surf.Area= 16,040 sf Storage= 44,305 cf
Plug-Flow detention time= 591.9 min calculated for 1.619 af (98% of inflow)
Center-of-Mass det. time= 580.4 min ( 1,356.0 - 775.6 )
Volume Invert Avail.Storage Storage Description
#1 659.00' 74,701 cf Temporary Pool (Irregular) Listed below (Recalc)
Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area
(feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft)
659.00 11,279 457.0 0 0 11,279
660.00 12,679 475.0 11,972 11,972 12,693
661.00 14,134 495.0 13,400 25,372 14,311
662.00 15,646 513.0 14,884 40,256 15,840
663.00 17,215 532.0 16,424 56,680 17,505
664.00 18,840 551.0 18,021 74,701 19,229
Device Routing Invert Outlet Devices
#1 Primary 659.00'18.0" Round Culvert
L= 700.0' RCP, groove end projecting, Ke= 0.200
Inlet / Outlet Invert= 659.00' / 659.00' S= 0.0000 '/' Cc= 0.900
n= 0.013, Flow Area= 1.77 sf
#2 Secondary 662.90'30.0' long x 10.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=4.04 cfs @ 12.55 hrs HW=662.20' TW=661.06' (Dynamic Tailwater)
1=Culvert (Outlet Controls 4.04 cfs @ 2.29 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=659.00' TW=0.00' (Dynamic Tailwater)
2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Type II 24-hr 25-Year Rainfall=6.22"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 33HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Pond 9P: Wet Pond 1 East
Inflow
Outflow
Primary
Secondary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Inflow Area=3.840 ac
Peak Elev=662.26'
Storage=44,305 cf
32.51 cfs
4.01 cfs
4.01 cfs
0.00 cfs
Type II 24-hr 25-Year Rainfall=6.22"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 34HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 10P: Wet Pond 1 West
Inflow Area = 8.950 ac, 70.61% Impervious, Inflow Depth > 4.93" for 25-Year event
Inflow = 42.78 cfs @ 11.95 hrs, Volume= 3.680 af
Outflow = 23.09 cfs @ 12.05 hrs, Volume= 3.662 af, Atten= 46%, Lag= 5.5 min
Primary = 23.09 cfs @ 12.05 hrs, Volume= 3.662 af
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Dyn-Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 662.06' @ 12.05 hrs Surf.Area= 12,376 sf Storage= 31,506 cf
Plug-Flow detention time= 220.7 min calculated for 3.662 af (100% of inflow)
Center-of-Mass det. time= 194.4 min ( 1,231.3 - 1,036.9 )
Volume Invert Avail.Storage Storage Description
#1 659.00' 58,288 cf Temporary Pool (Irregular) Listed below (Recalc)
Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area
(feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft)
659.00 8,330 413.0 0 0 8,330
660.00 9,595 431.0 8,955 8,955 9,610
661.00 10,920 450.0 10,250 19,205 11,013
662.00 12,297 469.0 11,602 30,807 12,477
663.00 13,733 488.0 13,008 43,815 14,001
664.00 15,225 507.0 14,473 58,288 15,586
Device Routing Invert Outlet Devices
#1 Primary 659.00'24.0" Round RCP_Round 24"
L= 20.0' RCP, groove end projecting, Ke= 0.200
Inlet / Outlet Invert= 659.00' / 658.90' S= 0.0050 '/' Cc= 0.900
n= 0.011 Concrete pipe, straight & clean, Flow Area= 3.14 sf
#2 Device 1 659.00'2.0" Vert. Orifice/Grate C= 0.600
#3 Device 1 660.00'24.0" W x 12.0" H Vert. Orifice/Grate C= 0.600
#4 Device 1 661.00'16.0' long Sharp-Crested Rectangular Weir 1 End Contraction(s)
#5 Secondary 662.50'40.0' long x 10.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=23.03 cfs @ 12.05 hrs HW=662.05' TW=0.00' (Dynamic Tailwater)
1=RCP_Round 24" (Barrel Controls 23.03 cfs @ 7.33 fps)
2=Orifice/Grate (Passes < 0.18 cfs potential flow)
3=Orifice/Grate (Passes < 11.94 cfs potential flow)
4=Sharp-Crested Rectangular Weir (Passes < 55.90 cfs potential flow)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=659.00' TW=0.00' (Dynamic Tailwater)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Type II 24-hr 25-Year Rainfall=6.22"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 35HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Pond 10P: Wet Pond 1 West
Inflow
Outflow
Primary
Secondary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)45
40
35
30
25
20
15
10
5
0
Inflow Area=8.950 ac
Peak Elev=662.06'
Storage=31,506 cf
42.78 cfs
23.09 cfs
23.09 cfs
0.00 cfs
Type II 24-hr 25-Year Rainfall=6.22"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 36HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 15P: Wet Pond 1 East Permanent Pool
Volume Invert Avail.Storage Storage Description
#1 654.00' 30,754 cf Main Pool (Irregular) Listed below (Recalc)
#2 654.00' 4,912 cf Forebay (Irregular) Listed below (Recalc)
35,666 cf Total Available Storage
Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area
(feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft)
654.00 4,441 296.0 0 0 4,441
655.00 5,048 309.0 4,741 4,741 5,136
656.00 5,681 323.0 5,361 10,103 5,908
657.00 6,341 336.0 6,008 16,111 6,665
658.00 7,027 349.0 6,681 22,792 7,452
659.00 8,936 385.0 7,962 30,754 9,587
Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area
(feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft)
654.00 300 86.0 0 0 300
655.00 494 108.0 393 393 653
656.00 735 133.0 611 1,004 1,148
657.00 1,028 159.0 877 1,881 1,769
658.00 1,371 183.0 1,195 3,076 2,444
659.00 2,343 233.0 1,835 4,912 4,113
Type II 24-hr 25-Year Rainfall=6.22"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 37HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 16P: Wet Pond 1 West Permanent Pool
Volume Invert Avail.Storage Storage Description
#1 653.00' 21,284 cf Main Pool (Irregular) Listed below (Recalc)
#2 656.00' 3,198 cf Forebay (Irregular) Listed below (Recalc)
24,482 cf Total Available Storage
Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area
(feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft)
653.00 1,791 244.0 0 0 1,791
654.00 2,297 261.0 2,039 2,039 2,519
655.00 2,837 278.0 2,562 4,601 3,297
656.00 3,409 293.0 3,119 7,720 4,036
657.00 4,011 308.0 3,706 11,426 4,813
658.00 4,644 324.0 4,324 15,749 5,678
659.00 6,476 298.0 5,535 21,284 7,002
Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area
(feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft)
656.00 620 112.0 0 0 620
657.00 858 126.0 736 736 911
658.00 1,125 141.0 988 1,724 1,256
659.00 1,853 114.0 1,474 3,198 1,819
Type II 24-hr 25-Year Rainfall=6.22"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 38HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Link 15L: Post DA-1
Inflow Area = 8.950 ac, 70.61% Impervious, Inflow Depth > 4.91" for 25-Year event
Inflow = 23.09 cfs @ 12.05 hrs, Volume= 3.662 af
Primary = 23.09 cfs @ 12.05 hrs, Volume= 3.662 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Link 15L: Post DA-1
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)24
22
20
18
16
14
12
10
8
6
4
2
0
Inflow Area=8.950 ac
23.09 cfs
23.09 cfs
Type II 24-hr 25-Year Rainfall=6.22"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 39HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Link 16L: Post DA-2
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Link 16L: Post DA-2
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)1
0
0.00 cfs
0.00 cfs
Type II 24-hr 100-Year Rainfall=7.87"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 40HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Time span=0.00-120.00 hrs, dt=0.05 hrs, 2401 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method
Runoff Area=5.910 ac 0.00% Impervious Runoff Depth=5.39"Subcatchment 1S: Pre DA 1
Flow Length=605' Tc=20.0 min CN=79 Runoff=34.88 cfs 2.653 af
Runoff Area=1.340 ac 0.00% Impervious Runoff Depth=5.39"Subcatchment 2S: Pre DA 2
Flow Length=312' Tc=14.9 min CN=79 Runoff=9.16 cfs 0.602 af
Runoff Area=1.220 ac 41.07% Impervious Runoff Depth=6.32"Subcatchment 3S: Pre DA-3
Flow Length=375' Tc=16.1 min CN=87 Runoff=9.11 cfs 0.643 af
Runoff Area=1.930 ac 10.00% Impervious Runoff Depth=6.09"Subcatchment 4S: Pre DA-4
Flow Length=303' Tc=11.8 min CN=85 Runoff=15.98 cfs 0.979 af
Runoff Area=5.110 ac 66.54% Impervious Runoff Depth=6.44"Subcatchment 5S: Post DA-1
Tc=5.0 min CN=88 Runoff=54.24 cfs 2.743 af
Runoff Area=3.840 ac 76.04% Impervious Runoff Depth=6.80"Subcatchment 6S: Post DA-2
Tc=5.0 min CN=91 Runoff=41.96 cfs 2.175 af
Runoff Area=0.590 ac 42.37% Impervious Runoff Depth=6.44"Subcatchment 7S: Post DA-3
Tc=5.0 min CN=88 Runoff=6.26 cfs 0.317 af
Runoff Area=0.860 ac 37.21% Impervious Runoff Depth=6.32"Subcatchment 8S: Post DA-4
Tc=6.0 min CN=87 Runoff=8.67 cfs 0.453 af
Peak Elev=662.99' Storage=56,497 cf Inflow=41.96 cfs 2.175 afPond 9P: Wet Pond 1 East
Primary=4.96 cfs 2.096 af Secondary=2.00 cfs 0.043 af Outflow=5.51 cfs 2.139 af
Peak Elev=662.64' Storage=38,969 cf Inflow=56.53 cfs 4.839 afPond 10P: Wet Pond 1 West
Primary=28.33 cfs 4.794 af Secondary=5.14 cfs 0.027 af Outflow=33.46 cfs 4.821 af
Peak Elev=0.00' Storage=0 cfPond 15P: Wet Pond 1 East Permanent Pool
Peak Elev=0.00' Storage=0 cfPond 16P: Wet Pond 1 West Permanent Pool
Inflow=33.46 cfs 4.821 afLink 15L: Post DA-1
Primary=33.46 cfs 4.821 af
Inflow=2.00 cfs 0.043 afLink 16L: Post DA-2
Primary=2.00 cfs 0.043 af
Total Runoff Area = 20.800 ac Runoff Volume = 10.564 af Average Runoff Depth = 6.09"
63.54% Pervious = 13.216 ac 36.46% Impervious = 7.584 ac
Type II 24-hr 100-Year Rainfall=7.87"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 41HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 1S: Pre DA 1
Runoff = 34.88 cfs @ 12.12 hrs, Volume= 2.653 af, Depth= 5.39"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 100-Year Rainfall=7.87"
Area (ac) CN Description
0.182 60 Woods, Fair, HSG B
0.565 79 Woods, Fair, HSG D
1.592 69 Pasture/grassland/range, Fair, HSG B
3.571 84 Pasture/grassland/range, Fair, HSG D
5.910 79 Weighted Average
5.910 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
9.7 75 0.0100 0.13 Sheet Flow, Sheet Flow
Grass: Short n= 0.150 P2= 3.57"
10.3 530 0.0150 0.86 Shallow Concentrated Flow, Shallow Concentrated Flow
Short Grass Pasture Kv= 7.0 fps
20.0 605 Total
Subcatchment 1S: Pre DA 1
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Type II 24-hr
100-Year Rainfall=7.87"
Runoff Area=5.910 ac
Runoff Volume=2.653 af
Runoff Depth=5.39"
Flow Length=605'
Tc=20.0 min
CN=79
34.88 cfs
Type II 24-hr 100-Year Rainfall=7.87"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 42HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 2S: Pre DA 2
Runoff = 9.16 cfs @ 12.07 hrs, Volume= 0.602 af, Depth= 5.39"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 100-Year Rainfall=7.87"
Area (ac) CN Description
0.365 79 Woods, Fair, HSG D
0.285 69 Pasture/grassland/range, Fair, HSG B
0.690 84 Pasture/grassland/range, Fair, HSG D
1.340 79 Weighted Average
1.340 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
9.7 75 0.0100 0.13 Sheet Flow, Sheet Flow
Grass: Short n= 0.150 P2= 3.57"
5.2 237 0.0116 0.75 Shallow Concentrated Flow, Shallow Concentrated Flow
Short Grass Pasture Kv= 7.0 fps
14.9 312 Total
Subcatchment 2S: Pre DA 2
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)10
9
8
7
6
5
4
3
2
1
0
Type II 24-hr
100-Year Rainfall=7.87"
Runoff Area=1.340 ac
Runoff Volume=0.602 af
Runoff Depth=5.39"
Flow Length=312'
Tc=14.9 min
CN=79
9.16 cfs
Type II 24-hr 100-Year Rainfall=7.87"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 43HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 3S: Pre DA-3
Runoff = 9.11 cfs @ 12.08 hrs, Volume= 0.643 af, Depth= 6.32"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 100-Year Rainfall=7.87"
Area (ac) CN Description
0.501 98 Paved parking, HSG D
0.719 80 >75% Grass cover, Good, HSG D
1.220 87 Weighted Average
0.719 58.93% Pervious Area
0.501 41.07% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
9.7 75 0.0100 0.13 Sheet Flow, Sheet Flow
Grass: Short n= 0.150 P2= 3.57"
6.4 300 0.0125 0.78 Shallow Concentrated Flow, Shallow Concentrated Flow
Short Grass Pasture Kv= 7.0 fps
16.1 375 Total
Subcatchment 3S: Pre DA-3
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)10
9
8
7
6
5
4
3
2
1
0
Type II 24-hr
100-Year Rainfall=7.87"
Runoff Area=1.220 ac
Runoff Volume=0.643 af
Runoff Depth=6.32"
Flow Length=375'
Tc=16.1 min
CN=87
9.11 cfs
Type II 24-hr 100-Year Rainfall=7.87"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 44HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 4S: Pre DA-4
Runoff = 15.98 cfs @ 12.03 hrs, Volume= 0.979 af, Depth= 6.09"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 100-Year Rainfall=7.87"
Area (ac) CN Description
1.530 84 Pasture/grassland/range, Fair, HSG D
0.207 79 Woods, Fair, HSG D
0.193 98 Paved parking, HSG D
1.930 85 Weighted Average
1.737 90.00% Pervious Area
0.193 10.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
8.7 75 0.0133 0.14 Sheet Flow, Sheet Flow
Grass: Short n= 0.150 P2= 3.57"
3.1 228 0.0305 1.22 Shallow Concentrated Flow, Shallow Concentrated Flow
Short Grass Pasture Kv= 7.0 fps
11.8 303 Total
Subcatchment 4S: Pre DA-4
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Type II 24-hr
100-Year Rainfall=7.87"
Runoff Area=1.930 ac
Runoff Volume=0.979 af
Runoff Depth=6.09"
Flow Length=303'
Tc=11.8 min
CN=85
15.98 cfs
Type II 24-hr 100-Year Rainfall=7.87"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 45HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 5S: Post DA-1
Runoff = 54.24 cfs @ 11.95 hrs, Volume= 2.743 af, Depth= 6.44"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 100-Year Rainfall=7.87"
Area (ac) CN Description
2.850 98 Paved parking, HSG D
1.070 61 >75% Grass cover, Good, HSG B
0.640 80 >75% Grass cover, Good, HSG D
0.320 98 Water Surface, HSG A
0.230 98 Paved parking, HSG A
5.110 88 Weighted Average
1.710 33.46% Pervious Area
3.400 66.54% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry, Direct Entry
Subcatchment 5S: Post DA-1
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)60
55
50
45
40
35
30
25
20
15
10
5
0
Type II 24-hr
100-Year Rainfall=7.87"
Runoff Area=5.110 ac
Runoff Volume=2.743 af
Runoff Depth=6.44"
Tc=5.0 min
CN=88
54.24 cfs
Type II 24-hr 100-Year Rainfall=7.87"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 46HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 6S: Post DA-2
Runoff = 41.96 cfs @ 11.95 hrs, Volume= 2.175 af, Depth= 6.80"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 100-Year Rainfall=7.87"
Area (ac) CN Description
2.520 98 Paved parking, HSG D
0.370 80 >75% Grass cover, Good, HSG D
0.550 61 >75% Grass cover, Good, HSG B
0.400 98 Water Surface, HSG A
3.840 91 Weighted Average
0.920 23.96% Pervious Area
2.920 76.04% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry, Direct Entry
Subcatchment 6S: Post DA-2
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)46
44
42
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Type II 24-hr
100-Year Rainfall=7.87"
Runoff Area=3.840 ac
Runoff Volume=2.175 af
Runoff Depth=6.80"
Tc=5.0 min
CN=91
41.96 cfs
Type II 24-hr 100-Year Rainfall=7.87"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 47HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 7S: Post DA-3
Runoff = 6.26 cfs @ 11.95 hrs, Volume= 0.317 af, Depth= 6.44"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 100-Year Rainfall=7.87"
Area (ac) CN Description
0.250 98 Paved parking, HSG B
0.340 80 >75% Grass cover, Good, HSG D
0.590 88 Weighted Average
0.340 57.63% Pervious Area
0.250 42.37% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 7S: Post DA-3
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)7
6
5
4
3
2
1
0
Type II 24-hr
100-Year Rainfall=7.87"
Runoff Area=0.590 ac
Runoff Volume=0.317 af
Runoff Depth=6.44"
Tc=5.0 min
CN=88
6.26 cfs
Type II 24-hr 100-Year Rainfall=7.87"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 48HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Subcatchment 8S: Post DA-4
Runoff = 8.67 cfs @ 11.96 hrs, Volume= 0.453 af, Depth= 6.32"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 100-Year Rainfall=7.87"
Area (ac) CN Description
0.320 98 Paved parking, HSG D
0.540 80 >75% Grass cover, Good, HSG D
0.860 87 Weighted Average
0.540 62.79% Pervious Area
0.320 37.21% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
6.0 Direct Entry,
Subcatchment 8S: Post DA-4
Runoff
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)9
8
7
6
5
4
3
2
1
0
Type II 24-hr
100-Year Rainfall=7.87"
Runoff Area=0.860 ac
Runoff Volume=0.453 af
Runoff Depth=6.32"
Tc=6.0 min
CN=87
8.67 cfs
Type II 24-hr 100-Year Rainfall=7.87"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 49HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 9P: Wet Pond 1 East
Inflow Area = 3.840 ac, 76.04% Impervious, Inflow Depth = 6.80" for 100-Year event
Inflow = 41.96 cfs @ 11.95 hrs, Volume= 2.175 af
Outflow = 5.51 cfs @ 12.29 hrs, Volume= 2.139 af, Atten= 87%, Lag= 20.5 min
Primary = 4.96 cfs @ 12.66 hrs, Volume= 2.096 af
Secondary = 2.00 cfs @ 12.22 hrs, Volume= 0.043 af
Routing by Dyn-Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 662.99' @ 12.22 hrs Surf.Area= 17,198 sf Storage= 56,497 cf
Plug-Flow detention time= 490.7 min calculated for 2.138 af (98% of inflow)
Center-of-Mass det. time= 482.2 min ( 1,250.8 - 768.6 )
Volume Invert Avail.Storage Storage Description
#1 659.00' 74,701 cf Temporary Pool (Irregular) Listed below (Recalc)
Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area
(feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft)
659.00 11,279 457.0 0 0 11,279
660.00 12,679 475.0 11,972 11,972 12,693
661.00 14,134 495.0 13,400 25,372 14,311
662.00 15,646 513.0 14,884 40,256 15,840
663.00 17,215 532.0 16,424 56,680 17,505
664.00 18,840 551.0 18,021 74,701 19,229
Device Routing Invert Outlet Devices
#1 Primary 659.00'18.0" Round Culvert
L= 700.0' RCP, groove end projecting, Ke= 0.200
Inlet / Outlet Invert= 659.00' / 659.00' S= 0.0000 '/' Cc= 0.900
n= 0.013, Flow Area= 1.77 sf
#2 Secondary 662.90'30.0' long x 10.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=4.99 cfs @ 12.66 hrs HW=662.84' TW=661.11' (Dynamic Tailwater)
1=Culvert (Outlet Controls 4.99 cfs @ 2.82 fps)
Secondary OutFlow Max=1.95 cfs @ 12.22 hrs HW=662.99' TW=0.00' (Dynamic Tailwater)
2=Broad-Crested Rectangular Weir (Weir Controls 1.95 cfs @ 0.74 fps)
Type II 24-hr 100-Year Rainfall=7.87"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 50HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Pond 9P: Wet Pond 1 East
Inflow
Outflow
Primary
Secondary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)46
44
42
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Inflow Area=3.840 ac
Peak Elev=662.99'
Storage=56,497 cf
41.96 cfs
5.51 cfs
4.96 cfs
2.00 cfs
Type II 24-hr 100-Year Rainfall=7.87"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 51HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 10P: Wet Pond 1 West
Inflow Area = 8.950 ac, 70.61% Impervious, Inflow Depth > 6.49" for 100-Year event
Inflow = 56.53 cfs @ 11.95 hrs, Volume= 4.839 af
Outflow = 33.46 cfs @ 12.05 hrs, Volume= 4.821 af, Atten= 41%, Lag= 5.6 min
Primary = 28.33 cfs @ 12.04 hrs, Volume= 4.794 af
Secondary = 5.14 cfs @ 12.05 hrs, Volume= 0.027 af
Routing by Dyn-Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 662.64' @ 12.04 hrs Surf.Area= 13,207 sf Storage= 38,969 cf
Plug-Flow detention time= 176.5 min calculated for 4.821 af (100% of inflow)
Center-of-Mass det. time= 156.1 min ( 1,143.6 - 987.5 )
Volume Invert Avail.Storage Storage Description
#1 659.00' 58,288 cf Temporary Pool (Irregular) Listed below (Recalc)
Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area
(feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft)
659.00 8,330 413.0 0 0 8,330
660.00 9,595 431.0 8,955 8,955 9,610
661.00 10,920 450.0 10,250 19,205 11,013
662.00 12,297 469.0 11,602 30,807 12,477
663.00 13,733 488.0 13,008 43,815 14,001
664.00 15,225 507.0 14,473 58,288 15,586
Device Routing Invert Outlet Devices
#1 Primary 659.00'24.0" Round RCP_Round 24"
L= 20.0' RCP, groove end projecting, Ke= 0.200
Inlet / Outlet Invert= 659.00' / 658.90' S= 0.0050 '/' Cc= 0.900
n= 0.011 Concrete pipe, straight & clean, Flow Area= 3.14 sf
#2 Device 1 659.00'2.0" Vert. Orifice/Grate C= 0.600
#3 Device 1 660.00'24.0" W x 12.0" H Vert. Orifice/Grate C= 0.600
#4 Device 1 661.00'16.0' long Sharp-Crested Rectangular Weir 1 End Contraction(s)
#5 Secondary 662.50'40.0' long x 10.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=28.22 cfs @ 12.04 hrs HW=662.63' TW=0.00' (Dynamic Tailwater)
1=RCP_Round 24" (Barrel Controls 28.22 cfs @ 8.98 fps)
2=Orifice/Grate (Passes < 0.20 cfs potential flow)
3=Orifice/Grate (Passes < 14.01 cfs potential flow)
4=Sharp-Crested Rectangular Weir (Passes < 107.46 cfs potential flow)
Secondary OutFlow Max=4.76 cfs @ 12.05 hrs HW=662.63' TW=0.00' (Dynamic Tailwater)
5=Broad-Crested Rectangular Weir (Weir Controls 4.76 cfs @ 0.90 fps)
Type II 24-hr 100-Year Rainfall=7.87"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 52HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Pond 10P: Wet Pond 1 West
Inflow
Outflow
Primary
Secondary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)60
55
50
45
40
35
30
25
20
15
10
5
0
Inflow Area=8.950 ac
Peak Elev=662.64'
Storage=38,969 cf
56.53 cfs
33.46 cfs
28.33 cfs
5.14 cfs
Type II 24-hr 100-Year Rainfall=7.87"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 53HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 15P: Wet Pond 1 East Permanent Pool
Volume Invert Avail.Storage Storage Description
#1 654.00' 30,754 cf Main Pool (Irregular) Listed below (Recalc)
#2 654.00' 4,912 cf Forebay (Irregular) Listed below (Recalc)
35,666 cf Total Available Storage
Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area
(feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft)
654.00 4,441 296.0 0 0 4,441
655.00 5,048 309.0 4,741 4,741 5,136
656.00 5,681 323.0 5,361 10,103 5,908
657.00 6,341 336.0 6,008 16,111 6,665
658.00 7,027 349.0 6,681 22,792 7,452
659.00 8,936 385.0 7,962 30,754 9,587
Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area
(feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft)
654.00 300 86.0 0 0 300
655.00 494 108.0 393 393 653
656.00 735 133.0 611 1,004 1,148
657.00 1,028 159.0 877 1,881 1,769
658.00 1,371 183.0 1,195 3,076 2,444
659.00 2,343 233.0 1,835 4,912 4,113
Type II 24-hr 100-Year Rainfall=7.87"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 54HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Pond 16P: Wet Pond 1 West Permanent Pool
Volume Invert Avail.Storage Storage Description
#1 653.00' 21,284 cf Main Pool (Irregular) Listed below (Recalc)
#2 656.00' 3,198 cf Forebay (Irregular) Listed below (Recalc)
24,482 cf Total Available Storage
Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area
(feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft)
653.00 1,791 244.0 0 0 1,791
654.00 2,297 261.0 2,039 2,039 2,519
655.00 2,837 278.0 2,562 4,601 3,297
656.00 3,409 293.0 3,119 7,720 4,036
657.00 4,011 308.0 3,706 11,426 4,813
658.00 4,644 324.0 4,324 15,749 5,678
659.00 6,476 298.0 5,535 21,284 7,002
Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area
(feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft)
656.00 620 112.0 0 0 620
657.00 858 126.0 736 736 911
658.00 1,125 141.0 988 1,724 1,256
659.00 1,853 114.0 1,474 3,198 1,819
Type II 24-hr 100-Year Rainfall=7.87"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 55HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Link 15L: Post DA-1
Inflow Area = 8.950 ac, 70.61% Impervious, Inflow Depth > 6.46" for 100-Year event
Inflow = 33.46 cfs @ 12.05 hrs, Volume= 4.821 af
Primary = 33.46 cfs @ 12.05 hrs, Volume= 4.821 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Link 15L: Post DA-1
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Inflow Area=8.950 ac
33.46 cfs
33.46 cfs
Type II 24-hr 100-Year Rainfall=7.87"NCC182110 - Arka Heights - 200421
Printed 6/26/2020Prepared by Bohler Engineering
Page 56HydroCAD® 10.00-20 s/n 09920 © 2017 HydroCAD Software Solutions LLC
Summary for Link 16L: Post DA-2
Inflow = 2.00 cfs @ 12.22 hrs, Volume= 0.043 af
Primary = 2.00 cfs @ 12.22 hrs, Volume= 0.043 af, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Link 16L: Post DA-2
Inflow
Primary
Hydrograph
Time (hours)
12011511010510095908580757065605550454035302520151050Flow (cfs)2
1
0
2.00 cfs
2.00 cfs
Impervious Value 0.98
Pervious Value 0.30
Drainage Area Total Area Impervious Area Pervious Area Weighted C
Ex Culvert 1 51,889 18,640 33,249 0.54
Ex Culvert 2 15,238 6,244 8,994 0.58
C2 23,146 6,601 16,545 0.49
Rational C Calculations
Culvert Report
Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Wednesday, Apr 22 2020
Ex. Culvert 1 (West)
Invert Elev Dn (ft) = 661.69
Pipe Length (ft) = 65.00
Slope (%) = 2.17
Invert Elev Up (ft) = 663.10
Rise (in) = 24.0
Shape = Circular
Span (in) = 24.0
No. Barrels = 1
n-Value = 0.012
Culvert Type = Circular Concrete
Culvert Entrance = Groove end projecting (C)
Coeff. K,M,c,Y,k = 0.0045, 2, 0.0317, 0.69, 0.2
Embankment
Top Elevation (ft) = 667.13
Top Width (ft) = 50.00
Crest Width (ft) = 50.00
Calculations
Qmin (cfs) = 6.89
Qmax (cfs) = 6.89
Tailwater Elev (ft) = (dc+D)/2
Highlighted
Qtotal (cfs) = 6.89
Qpipe (cfs) = 6.89
Qovertop (cfs) = 0.00
Veloc Dn (ft/s) = 2.79
Veloc Up (ft/s) = 4.81
HGL Dn (ft) = 663.16
HGL Up (ft) = 664.03
Hw Elev (ft) = 664.39
Hw/D (ft) = 0.65
Flow Regime = Inlet Control
Q = CiACf
C = 0.54
i = 8.94
A = 1.19 Acres
Cf = 1.2 (50-yr)
Culvert Report
Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Wednesday, Apr 22 2020
Ex. Culvert 2 (East)
Invert Elev Dn (ft) = 661.12
Pipe Length (ft) = 54.00
Slope (%) = 2.74
Invert Elev Up (ft) = 662.60
Rise (in) = 18.0
Shape = Circular
Span (in) = 18.0
No. Barrels = 1
n-Value = 0.012
Culvert Type = Circular Concrete
Culvert Entrance = Groove end projecting (C)
Coeff. K,M,c,Y,k = 0.0045, 2, 0.0317, 0.69, 0.2
Embankment
Top Elevation (ft) = 665.93
Top Width (ft) = 34.00
Crest Width (ft) = 50.00
Calculations
Qmin (cfs) = 5.00
Qmax (cfs) = 5.00
Tailwater Elev (ft) = (dc+D)/2
Highlighted
Qtotal (cfs) = 5.00
Qpipe (cfs) = 5.00
Qovertop (cfs) = 0.00
Veloc Dn (ft/s) = 3.35
Veloc Up (ft/s) = 4.77
HGL Dn (ft) = 662.30
HGL Up (ft) = 663.46
Hw Elev (ft) = 663.83
Hw/D (ft) = 0.82
Flow Regime = Inlet Control
Q = CiACf
C = 0.53
i = 8.94
A = 0.88 Acres
Cf = 1.2 (50-yr)
Culvert Report
Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Wednesday, Apr 22 2020
P-C2
Invert Elev Dn (ft) = 662.79
Pipe Length (ft) = 60.00
Slope (%) = 0.50
Invert Elev Up (ft) = 663.09
Rise (in) = 18.0
Shape = Circular
Span (in) = 18.0
No. Barrels = 1
n-Value = 0.012
Culvert Type = Circular Concrete
Culvert Entrance = Square edge w/headwall (C)
Coeff. K,M,c,Y,k = 0.0098, 2, 0.0398, 0.67, 0.5
Embankment
Top Elevation (ft) = 666.00
Top Width (ft) = 20.00
Crest Width (ft) = 20.00
Calculations
Qmin (cfs) = 2.79
Qmax (cfs) = 2.79
Tailwater Elev (ft) = (dc+D)/2
Highlighted
Qtotal (cfs) = 2.79
Qpipe (cfs) = 2.79
Qovertop (cfs) = 0.00
Veloc Dn (ft/s) = 2.08
Veloc Up (ft/s) = 3.93
HGL Dn (ft) = 663.86
HGL Up (ft) = 663.72
Hw Elev (ft) = 663.98
Hw/D (ft) = 0.60
Flow Regime = Inlet Control
Q = CiACf
C = 0.49
i = 8.94
A = 0.53 Acres
Cf = 1.2 (50-yr)
Channel Report
Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Wednesday, Apr 22 2020
Ex. Culvert 1 - Roadside Ditch - 10-yr Storm
Trapezoidal
Bottom Width (ft) = 6.00
Side Slopes (z:1) = 4.00, 3.00
Total Depth (ft) = 1.00
Invert Elev (ft) = 663.10
Slope (%) = 1.00
N-Value = 0.030
Calculations
Compute by: Known Q
Known Q (cfs) = 4.88
Highlighted
Depth (ft) = 0.33
Q (cfs) = 4.880
Area (sqft) = 2.36
Velocity (ft/s) = 2.07
Wetted Perim (ft) = 8.40
Crit Depth, Yc (ft) = 0.26
Top Width (ft) = 8.31
EGL (ft) = 0.40
0 2 4 6 8 10 12 14 16 18
Elev (ft)Depth (ft)Section
662.50 -0.60
663.00 -0.10
663.50 0.40
664.00 0.90
664.50 1.40
665.00 1.90
Reach (ft)
Q = CiA
C = 0.54
i = 7.6
A = 1.19 Acres
Channel Report
Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Wednesday, Apr 22 2020
C-2 - Roadside Ditch - 10-yr Storm
Trapezoidal
Bottom Width (ft) = 1.00
Side Slopes (z:1) = 3.00, 3.00
Total Depth (ft) = 2.00
Invert Elev (ft) = 663.09
Slope (%) = 1.40
N-Value = 0.030
Calculations
Compute by: Known Q
Known Q (cfs) = 1.97
Highlighted
Depth (ft) = 0.40
Q (cfs) = 1.970
Area (sqft) = 0.88
Velocity (ft/s) = 2.24
Wetted Perim (ft) = 3.53
Crit Depth, Yc (ft) = 0.36
Top Width (ft) = 3.40
EGL (ft) = 0.48
0 2 4 6 8 10 12 14 16 18
Elev (ft)Depth (ft)Section
662.50 -0.59
663.00 -0.09
663.50 0.41
664.00 0.91
664.50 1.41
665.00 1.91
665.50 2.41
666.00 2.91
Reach (ft)
Q = CiA
C = 0.49
i = 7.6
A = 0.53 Acres
Structure Name:A-0Diameter 24 in 2 ftClassMidrangeQ 23.1 cfsA 4d500.5 feet 6 inB 8dmax9.00 inches1 10La13 feet2 14W 15 feetThickness 18 inchesW@outlet 6 feetClass B6.0 FT15.0 FT13.0 FT
Structure Name:A-1Diameter 30 in 2.5 ftClassMidrangeQ 25.3 cfsA 4d500.5 feet 6 inB 8dmax9.00 inches1 10La16 feet2 14W 18.5 feetThickness 18 inchesW@outlet 7.5 feetClass B7.5 FT18.5 FT16.0 FT
Structure Name:B-1Diameter 24 in 2 ftClassMidrangeQ 13.5 cfsA 4d500.4 feet 4.8 inB 8dmax7.20 inches1 10La13 feet2 14W 15 feetThickness 18 inchesW@outlet 6 feetClass B6.0 FT15.0 FT13.0 FT
Structure Name:B-7Diameter 18 in 1.5 ftClassMidrangeQ 3.9 cfsA 4d500.3 feet 3.6 inB 8dmax5.40 inches1 10La10 feet2 14W 11.5 feetThickness 9 inchesW@outlet 4.5 feetClass A4.5 FT11.5 FT10.0 FT
Structure Name:C-1Diameter 18 in 1.5 ftClassMidrangeQ 3.6 cfsA 4d500.3 feet 3.6 inB 8dmax5.40 inches1 10La10 feet2 14W 11.5 feetThickness 9 inchesW@outlet 4.5 feetClass A4.5 FT11.5 FT10.0 FT
Structure Name:Curb CutDiameter 0 in 0 ftClassMidrangeQ 4 cfsA 4d500.3 feet 3.6 inB 8dmax5.40 inches1 10La10 feet2 14W 10 feetThickness 9 inchesW@outlet 0 feetClass A0.0 FT10.0 FT10.0 FT
Okay
7.13 Disturbed Area (Acres)
20.43 Peak Flow from 10-year Storm (cfs) i = 5.21 in/hr
C = 0.55
12834.00 Required Volume ft3
8887.49 Required Surface Area ft2
66.66 Suggested Width ft
133.32 Suggested Length ft
90.00 Trial Top Width at Spillway Invert ft
205.00 Trial Top Length at Spillway Invert ft
3.00 Trial Side Slope Ratio Z:1
3.00 Trial Depth ft (2 to 3.5 feet above grade)
72.00 Bottom Width ft
187.00 Bottom Length ft
13464.00 Bottom Area ft2
47709.00 Actual Volume ft3 Okay
18450.00 Actual Surface Area ft2 Okay
7.50 Trial Weir Length ft
1.00 Trial Depth of Flow ft
22.50 Spillway Capacity cfs Okay
1.50 Skimmer Size (inches)
0.13 Head on Skimmer (feet)
2.25 Orifice Size (1/4 inch increments)
3.10 Dewatering Time (days)
Suggest about 3 days
Skimmer Basin 1
Okay
2.30 Disturbed Area (Acres)
6.59 Peak Flow from 10-year Storm (cfs) i = 5.21 in/hr
C = 0.55
4140.00 Required Volume ft3
2866.93 Required Surface Area ft2
37.86 Suggested Width ft
75.72 Suggested Length ft
160.00 Trial Top Width at Spillway Invert ft
210.00 Trial Top Length at Spillway Invert ft
2.00 Trial Side Slope Ratio Z:1
3.00 Trial Depth ft (2 to 3.5 feet above grade)
148.00 Bottom Width ft
198.00 Bottom Length ft
29304.00 Bottom Area ft2
94284.00 Actual Volume ft3 Okay
33600.00 Actual Surface Area ft2 Okay
10.00 Trial Weir Length ft
0.50 Trial Depth of Flow ft
10.61 Spillway Capacity cfs Okay
1.50 Skimmer Size (inches)
0.125 Head on Skimmer (feet)
1.25 Orifice Size (1/4 inch increments)
3.24 Dewatering Time (days)
Suggest about 3 days
Skimmer Basin 2