Conservation Commission Agenda (linked)

Drainage Report
Roberts Village Drive
Page 1 of 3 
Indigo Land Design, LLC         
860.388.9343 Phone
40 Elm Street, 2nd Floor          
860.391.8854 Fax
Old Saybrook, CT 06475          
jwren@Indigo-Land.com E-mail
www.Indigo-Land.com
May 21, 2024 
Re:
Roberts Court Extension (CGS § 8-30g Affordable Housing Development) 
430 Mohegan Ave. Parkway & 23B Old Norwich Rd. (Map 76 Lots 10164 & 5600)
Waterford, CT 06385
DRAINAGE REPORT
This project is for an affordable housing development, which includes construction of a 
new 20-foot wide and 797± linear foot long private looped road off the end of Roberts Court, 
construction of 20 residential buildings (16 single-family houses and 4 duplexes for a total of 24
dwelling units), installation of a storm sewer system, stormwater management areas, low impact 
development (LID) features, implementation of best management practices (BMP) and other 
associated improvements.
The existing site is a 5.22-acre parcel of land that fronts on Mohegan Avenue Parkway (CT Route 
32) toward the east and the cul-de-sac of Roberts Court toward the north. There are remains of 
an old shed on the northwest corner of the site and there is a sanitary sewer system and easement 
along the northeast property line. Other than that, the site is currently undeveloped woodlands, 
more or less. The on-site topography generally drains toward the east where there is a depression 
and a low-point near the southeast corner of the property. At the low-point in the depression there 
is a culvert inlet with a small 0.06-acre pocket of isolated inland wetlands around it. The culvert 
extends under Mohegan Avenue Parkway (CT Route 32) and daylights to a ditch on the opposite 
side of the road. 
The total existing and proposed watershed area is 16.5 acres and includes the entire site and 
approximately 11.3 acres of off-site area. The contributing off-site drainage area consists of 
undeveloped woodlands toward the south owned by Connecticut College, developed residential 
properties within the surrounding neighborhoods, and a portion of the Mohegan Avenue Parkway 

 
Drainage Report 
Roberts Village Drive 
Page 2 of 3 
 
right-of-way. The design points are the culvert inlet at the low-point as previously described 
(Design Point #1) and a point near the northwest corner of the property (Design Point #2). 
 
Based on NRCS soil mapping, the underlying soils throughout the existing and proposed 
watershed consists of Canton & Charlton, Paxton & Montauk, and Sutton soils. All of these soils 
are classified as fine sandy loams or fine sandy loams that are very stony. The NRCS hydrologic 
soil group rating is B for Canton & Charlton soils, C for Paxton & Montauk soils, and B/D for Sutton 
soils. The B/D rating indicates that the Sutton soils are soil group B when they are drained and 
soil group D when they are undrained. Soil group D was used for the wetland pocket due to the 
undrained or saturated condition. 
 
On-site soil testing was conducted in July 2023. Eight deep test pits were dug throughout the area 
of the proposed development, including three test holes within the vicinity of the stormwater 
management areas. The holes were dug between 7 to 9.5 feet deep and were observed by Robert 
Russo, C.P.S.S. The results showed that the underlying soils are a fine or very fine sandy loam 
or a silt loam with sand, gravel, cobbles, or stones near the bottom of the test holes, which is 
consistent with the NRCS soil mapping. 
 
While soil testing, Mr. Russo obtained three soil samples within the vicinity of the stormwater 
management areas and CLA Engineers, Inc. conducted permeability tests and sieve analysis. 
The infiltration rates are 0.25 inches per hour within the area of the smaller stormwater quality 
basin (Basin #1B) and 0.58 and 0.29 inches per hour (0.44 average) within the area of the large 
stormwater quality basin (Basin #1C). The infiltration rates are consistent with NRCS soil 
mapping. 
 
The NRCS TR-55 methodology was utilized to evaluate the existing and proposed stormwater 
runoff conditions using the embedded AutoCAD HydraFlow Hydrographs computer program. All 
times of concentration were computed using the TR-55 methodology as recommended by the 
ConnDOT Drainage Manual. The Town of Waterford recommends using the 24-hour NRCS Type 
III rainfall distribution for all storms. All rainfall amounts used in this analysis were taken from the 
Hydrometeorological Design Studies Center of the National Oceanic and Atmospheric 
Administration (NOAA) National Weather Service and published in NOAA Atlas 14 Volume 10: 

 
Drainage Report 
Roberts Village Drive 
Page 3 of 3 
 
Precipitation-Frequency Atlas of the United States, Northeastern States, last revised on 
September 30, 2015. Refer to the plans entitled “Watershed Mapping” enclosed within this report 
for all watershed information. 
 
Included with this report are HydraFlow supporting computations and hydrographs for the existing 
and proposed conditions. Detailed summaries of the computational results for the 2, 10, 25, 50, 
and 100-year storm events. The results indicate that the proposed peak rate of runoff and the 
volume of runoff at the design points will decrease for the 2- through 100-year storms. See tables 
in the enclosed drainage report. 
 
The stormwater basins will be wet bottom basins that will capture the majority of the development 
and will slowly infiltrate the water into the underlying soils over the course of several days. 
Additionally, the outlet control structures within the basins will slowly release runoff over time to 
reduce the peak rate of runoff. The basins will provide at least 1-foot of freeboard up to the top of 
the basin berms. Refer to the attached summary tables for tabulated results for peak rates of 
runoff, volume of runoff and water surface elevations for the pre- and post-development 
conditions. 
 
The proposed project includes several LID features and best management practices (BMP) to 
mitigate impacts of stormwater runoff and reduce the pollutant content of stormwater discharge. 
These methods include, but are not limited to: breaking up areas of impervious surfaces, avoiding 
concentrated point discharges, encouraging overland flow, using open swales, using pervious 
walkways and patios, inhibiting erosion by using pre-formed scour holes at pipe outfalls, 
minimizing the removal of existing trees to the extend possible, introducing new landscaping, and 
maintaining existing drainage patterns. 
 
In summary, the proposal is for an affordable housing development that will include a storm sewer 
system, stormwater management areas, LID features, and BMP techniques that will mitigate and 
enhance the stormwater runoff generated from the proposed development. The post-
development stormwater runoff reaching the design points will be less than the pre-development 
conditions. 





Hydraflow Table of Contents
EXIST-FINAL 5-21-24.gpw
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Tuesday, 05 / 21 / 2024
Watershed Model Schematic...................................................................................... 1
Hydrograph Return Period Recap............................................................................. 2
1 - Year
Summary Report......................................................................................................................... 3
Hydrograph Reports................................................................................................................... 4
Hydrograph No. 1, SCS Runoff, Area 1 / Design Pt 1.............................................................. 4
TR-55 Tc Worksheet............................................................................................................ 5
2 - Year
Summary Report......................................................................................................................... 6
Hydrograph Reports................................................................................................................... 7
Hydrograph No. 1, SCS Runoff, Area 1 / Design Pt 1.............................................................. 7
5 - Year
Summary Report......................................................................................................................... 8
Hydrograph Reports................................................................................................................... 9
Hydrograph No. 1, SCS Runoff, Area 1 / Design Pt 1.............................................................. 9
10 - Year
Summary Report....................................................................................................................... 10
Hydrograph Reports................................................................................................................. 11
Hydrograph No. 1, SCS Runoff, Area 1 / Design Pt 1............................................................ 11
25 - Year
Summary Report....................................................................................................................... 12
Hydrograph Reports................................................................................................................. 13
Hydrograph No. 1, SCS Runoff, Area 1 / Design Pt 1............................................................ 13
50 - Year
Summary Report....................................................................................................................... 14
Hydrograph Reports................................................................................................................. 15
Hydrograph No. 1, SCS Runoff, Area 1 / Design Pt 1............................................................ 15
100 - Year
Summary Report....................................................................................................................... 16
Hydrograph Reports................................................................................................................. 17
Hydrograph No. 1, SCS Runoff, Area 1 / Design Pt 1............................................................ 17
IDF Report.................................................................................................................. 18

1 - Area 1 / Design Pt 1
2 - Area 2 / Design Pt 2
1
Watershed Model Schematic
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Project: EXIST-FINAL 5-21-24.gpw
Tuesday, 05 / 21 / 2024
Hyd. Origin
Description
Legend
1
SCS Runoff
Area 1 / Design Pt 1
2
SCS Runoff
Area 2 / Design Pt 2

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
------
2.639
5.075
-------
10.09
14.95
22.27
28.13
34.71
Area 1 / Design Pt 1
2
SCS Runoff
------
0.121
0.277
-------
0.637
1.010
1.589
2.052
2.577
Area 2 / Design Pt 2
Proj. file: EXIST-FINAL 5-21-24.gpw
Tuesday, 05 / 21 / 2024
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022

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
2.639
3
756
22,157
------
------
------
Area 1 / Design Pt 1
2
SCS Runoff
0.121
3
747
1,035
------
------
------
Area 2 / Design Pt 2
EXIST-FINAL 5-21-24.gpw
Return Period: 1 Year
Tuesday, 05 / 21 / 2024
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Tuesday, 05 / 21 / 2024
Hyd. No. 1
Area 1 / Design Pt 1
Hydrograph type
=  SCS Runoff
Peak discharge
=  2.639 cfs
Storm frequency
=  1 yrs
Time to peak
=  756 min
Time interval
=  3 min
Hyd. volume
=  22,157 cuft
Drainage area
=  15.470 ac
Curve number
=  63
Basin Slope
=  0.0 %
Hydraulic length
=  0 ft
Tc method
=  TR55
Time of conc. (Tc)
=  30.20 min
Total precip.
=  2.89 in
Distribution
=  Type III
Storm duration
=  24 hrs
Shape factor
=  484
4
0
180
360
540
720
900
1080
1260
1440
1620
Q (cfs)
0.00
0.00
1.00
1.00
2.00
2.00
3.00
3.00
Q (cfs)
Time (min)
Area 1 / Design Pt 1
Hyd. No. 1 -- 1 Year
Hyd No. 1

TR55 Tc Worksheet
5
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Hyd. No. 1
Area 1 / Design Pt 1
Description
A
B
C
Totals
Sheet Flow
Manning's n-value
=  0.600
0.011
0.011
Flow length (ft)
=  150.0
0.0
0.0
Two-year 24-hr precip. (in)
=  3.45
0.00
0.00
Land slope (%)
=  5.30
0.00
0.00
Travel Time (min)
= 26.79
+
0.00
+
0.00
=
26.79
Shallow Concentrated Flow
Flow length (ft)
=  940.00
0.00
0.00
Watercourse slope (%)
=  8.10
0.00
0.00
Surface description
=  Unpaved
Unpaved
Unpaved
Average velocity (ft/s)
=4.59
0.00
0.00
Travel Time (min)
= 3.41
+
0.00
+
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 ..............................................................................
30.20 min

Hydrograph Summary Report
6
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
5.075
3
750
36,318
------
------
------
Area 1 / Design Pt 1
2
SCS Runoff
0.277
3
741
1,833
------
------
------
Area 2 / Design Pt 2
EXIST-FINAL 5-21-24.gpw
Return Period: 2 Year
Tuesday, 05 / 21 / 2024
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Tuesday, 05 / 21 / 2024
Hyd. No. 1
Area 1 / Design Pt 1
Hydrograph type
=  SCS Runoff
Peak discharge
=  5.075 cfs
Storm frequency
=  2 yrs
Time to peak
=  750 min
Time interval
=  3 min
Hyd. volume
=  36,318 cuft
Drainage area
=  15.470 ac
Curve number
=  63
Basin Slope
=  0.0 %
Hydraulic length
=  0 ft
Tc method
=  TR55
Time of conc. (Tc)
=  30.20 min
Total precip.
=  3.45 in
Distribution
=  Type III
Storm duration
=  24 hrs
Shape factor
=  484
7
0
180
360
540
720
900
1080
1260
1440
1620
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 (min)
Area 1 / Design Pt 1
Hyd. No. 1 -- 2 Year
Hyd No. 1

Hydrograph Summary Report
8
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
10.09
3
747
64,026
------
------
------
Area 1 / Design Pt 1
2
SCS Runoff
0.637
3
738
3,462
------
------
------
Area 2 / Design Pt 2
EXIST-FINAL 5-21-24.gpw
Return Period: 5 Year
Tuesday, 05 / 21 / 2024
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Tuesday, 05 / 21 / 2024
Hyd. No. 1
Area 1 / Design Pt 1
Hydrograph type
=  SCS Runoff
Peak discharge
=  10.09 cfs
Storm frequency
=  5 yrs
Time to peak
=  747 min
Time interval
=  3 min
Hyd. volume
=  64,026 cuft
Drainage area
=  15.470 ac
Curve number
=  63
Basin Slope
=  0.0 %
Hydraulic length
=  0 ft
Tc method
=  TR55
Time of conc. (Tc)
=  30.20 min
Total precip.
=  4.36 in
Distribution
=  Type III
Storm duration
=  24 hrs
Shape factor
=  484
9
0
180
360
540
720
900
1080
1260
1440
1620
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 (min)
Area 1 / Design Pt 1
Hyd. No. 1 -- 5 Year
Hyd No. 1

Hydrograph Summary Report
10
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
14.95
3
747
90,620
------
------
------
Area 1 / Design Pt 1
2
SCS Runoff
1.010
3
735
5,072
------
------
------
Area 2 / Design Pt 2
EXIST-FINAL 5-21-24.gpw
Return Period: 10 Year
Tuesday, 05 / 21 / 2024
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Tuesday, 05 / 21 / 2024
Hyd. No. 1
Area 1 / Design Pt 1
Hydrograph type
=  SCS Runoff
Peak discharge
=  14.95 cfs
Storm frequency
=  10 yrs
Time to peak
=  747 min
Time interval
=  3 min
Hyd. volume
=  90,620 cuft
Drainage area
=  15.470 ac
Curve number
=  63
Basin Slope
=  0.0 %
Hydraulic length
=  0 ft
Tc method
=  TR55
Time of conc. (Tc)
=  30.20 min
Total precip.
=  5.12 in
Distribution
=  Type III
Storm duration
=  24 hrs
Shape factor
=  484
11
0
180
360
540
720
900
1080
1260
1440
1620
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
Q (cfs)
Time (min)
Area 1 / Design Pt 1
Hyd. No. 1 -- 10 Year
Hyd No. 1

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
22.27
3
744
130,833
------
------
------
Area 1 / Design Pt 1
2
SCS Runoff
1.589
3
735
7,559
------
------
------
Area 2 / Design Pt 2
EXIST-FINAL 5-21-24.gpw
Return Period: 25 Year
Tuesday, 05 / 21 / 2024
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Tuesday, 05 / 21 / 2024
Hyd. No. 1
Area 1 / Design Pt 1
Hydrograph type
=  SCS Runoff
Peak discharge
=  22.27 cfs
Storm frequency
=  25 yrs
Time to peak
=  744 min
Time interval
=  3 min
Hyd. volume
=  130,833 cuft
Drainage area
=  15.470 ac
Curve number
=  63
Basin Slope
=  0.0 %
Hydraulic length
=  0 ft
Tc method
=  TR55
Time of conc. (Tc)
=  30.20 min
Total precip.
=  6.16 in
Distribution
=  Type III
Storm duration
=  24 hrs
Shape factor
=  484
13
0
180
360
540
720
900
1080
1260
1440
1620
Q (cfs)
0.00
0.00
4.00
4.00
8.00
8.00
12.00
12.00
16.00
16.00
20.00
20.00
24.00
24.00
Q (cfs)
Time (min)
Area 1 / Design Pt 1
Hyd. No. 1 -- 25 Year
Hyd No. 1

Hydrograph Summary Report
14
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
28.13
3
744
162,822
------
------
------
Area 1 / Design Pt 1
2
SCS Runoff
2.052
3
735
9,568
------
------
------
Area 2 / Design Pt 2
EXIST-FINAL 5-21-24.gpw
Return Period: 50 Year
Tuesday, 05 / 21 / 2024
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Tuesday, 05 / 21 / 2024
Hyd. No. 1
Area 1 / Design Pt 1
Hydrograph type
=  SCS Runoff
Peak discharge
=  28.13 cfs
Storm frequency
=  50 yrs
Time to peak
=  744 min
Time interval
=  3 min
Hyd. volume
=  162,822 cuft
Drainage area
=  15.470 ac
Curve number
=  63
Basin Slope
=  0.0 %
Hydraulic length
=  0 ft
Tc method
=  TR55
Time of conc. (Tc)
=  30.20 min
Total precip.
=  6.93 in
Distribution
=  Type III
Storm duration
=  24 hrs
Shape factor
=  484
15
0
180
360
540
720
900
1080
1260
1440
1620
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 (min)
Area 1 / Design Pt 1
Hyd. No. 1 -- 50 Year
Hyd No. 1

Hydrograph Summary Report
16
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
34.71
3
744
198,969
------
------
------
Area 1 / Design Pt 1
2
SCS Runoff
2.577
3
735
11,861
------
------
------
Area 2 / Design Pt 2
EXIST-FINAL 5-21-24.gpw
Return Period: 100 Year
Tuesday, 05 / 21 / 2024
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Tuesday, 05 / 21 / 2024
Hyd. No. 1
Area 1 / Design Pt 1
Hydrograph type
=  SCS Runoff
Peak discharge
=  34.71 cfs
Storm frequency
=  100 yrs
Time to peak
=  744 min
Time interval
=  3 min
Hyd. volume
=  198,969 cuft
Drainage area
=  15.470 ac
Curve number
=  63
Basin Slope
=  0.0 %
Hydraulic length
=  0 ft
Tc method
=  TR55
Time of conc. (Tc)
=  30.20 min
Total precip.
=  7.76 in
Distribution
=  Type III
Storm duration
=  24 hrs
Shape factor
=  484
17
0
180
360
540
720
900
1080
1260
1440
1620
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 (min)
Area 1 / Design Pt 1
Hyd. No. 1 -- 100 Year
Hyd No. 1

Hydraflow Rainfall Report
18
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Tuesday, 05 / 21 / 2024
Return
Intensity-Duration-Frequency Equation Coefficients (FHA)
Period
(Yrs)
B
D
E
(N/A)
1
0.0000
0.0000
0.0000
--------
2
69.8703
13.1000
0.8658
--------
3
0.0000
0.0000
0.0000
--------
5
79.2597
14.6000
0.8369
--------
10
88.2351
15.5000
0.8279
--------
25
102.6072
16.5000
0.8217
--------
50
114.8193
17.2000
0.8199
--------
100
127.1596
17.8000
0.8186
--------
File name: SampleFHA.idf
Intensity = B / (Tc + D)^E
Return
Intensity Values (in/hr)
Period
(Yrs)
5 min
10
15
20
25
30
35
40
45
50
55
60
1
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
2
5.69
4.61
3.89
3.38
2.99
2.69
2.44
2.24
2.07
1.93
1.81
1.70
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
6.57
5.43
4.65
4.08
3.65
3.30
3.02
2.79
2.59
2.42
2.27
2.15
10
7.24
6.04
5.21
4.59
4.12
3.74
3.43
3.17
2.95
2.77
2.60
2.46
25
8.25
6.95
6.03
5.34
4.80
4.38
4.02
3.73
3.48
3.26
3.07
2.91
50
9.04
7.65
6.66
5.92
5.34
4.87
4.49
4.16
3.88
3.65
3.44
3.25
100
9.83
8.36
7.30
6.50
5.87
5.36
4.94
4.59
4.29
4.03
3.80
3.60
Tc = time in minutes. Values may exceed 60.
Rainfall Precipitation Table (in)
OJECTS\2023\2023-922 Del Grosso - Roberts Court Waterford\DRAINAGE\DRAINAGE DEC 2023\PRECIP DATA.pcp
Storm
Distribution
1-yr
2-yr
3-yr
5-yr
10-yr
25-yr
50-yr
100-yr
SCS 24-hour
2.89
3.45
0.00
4.36
5.12
6.16
6.93
7.76
SCS 6-Hr
0.00
0.00
0.00
0.00
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


Hydraflow Table of Contents
PROP-FINAL 5-21-24.gpw
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Tuesday, 05 / 21 / 2024
Watershed Model Schematic...................................................................................... 1
Hydrograph Return Period Recap............................................................................. 2
2 - Year
Summary Report......................................................................................................................... 3
Hydrograph Reports................................................................................................................... 4
Hydrograph No. 1, SCS Runoff, Area 1A................................................................................. 4
TR-55 Tc Worksheet............................................................................................................ 5
Hydrograph No. 2, SCS Runoff, Area 1B................................................................................. 6
Hydrograph No. 3, SCS Runoff, Area 1C................................................................................. 7
TR-55 Tc Worksheet............................................................................................................ 8
Hydrograph No. 4, SCS Runoff, Area 2 / Design Pt 2.............................................................. 9
TR-55 Tc Worksheet.......................................................................................................... 10
Hydrograph No. 5, Reservoir, Basin 1B................................................................................. 11
Pond Report - Basin 1B..................................................................................................... 12
Hydrograph No. 6, Reservoir, Basin 1C................................................................................. 14
Pond Report - Basin 1C..................................................................................................... 15
Hydrograph No. 7, Combine, Design Pt 1.............................................................................. 17
10 - Year
Summary Report....................................................................................................................... 18
Hydrograph Reports................................................................................................................. 19
Hydrograph No. 1, SCS Runoff, Area 1A............................................................................... 19
Hydrograph No. 2, SCS Runoff, Area 1B............................................................................... 20
Hydrograph No. 3, SCS Runoff, Area 1C............................................................................... 21
Hydrograph No. 4, SCS Runoff, Area 2 / Design Pt 2............................................................ 22
Hydrograph No. 5, Reservoir, Basin 1B................................................................................. 23
Hydrograph No. 6, Reservoir, Basin 1C................................................................................. 24
Hydrograph No. 7, Combine, Design Pt 1.............................................................................. 25
25 - Year
Summary Report....................................................................................................................... 26
Hydrograph Reports................................................................................................................. 27
Hydrograph No. 1, SCS Runoff, Area 1A............................................................................... 27
Hydrograph No. 2, SCS Runoff, Area 1B............................................................................... 28
Hydrograph No. 3, SCS Runoff, Area 1C............................................................................... 29
Hydrograph No. 4, SCS Runoff, Area 2 / Design Pt 2............................................................ 30
Hydrograph No. 5, Reservoir, Basin 1B................................................................................. 31
Hydrograph No. 6, Reservoir, Basin 1C................................................................................. 32
Hydrograph No. 7, Combine, Design Pt 1.............................................................................. 33
50 - Year
Summary Report....................................................................................................................... 34
Hydrograph Reports................................................................................................................. 35
Hydrograph No. 1, SCS Runoff, Area 1A............................................................................... 35
Hydrograph No. 2, SCS Runoff, Area 1B............................................................................... 36
Hydrograph No. 3, SCS Runoff, Area 1C............................................................................... 37

Contents continued...
PROP-FINAL 5-21-24.gpw
Hydrograph No. 4, SCS Runoff, Area 2 / Design Pt 2............................................................ 38
Hydrograph No. 5, Reservoir, Basin 1B................................................................................. 39
Hydrograph No. 6, Reservoir, Basin 1C................................................................................. 40
Hydrograph No. 7, Combine, Design Pt 1.............................................................................. 41
100 - Year
Summary Report....................................................................................................................... 42
Hydrograph Reports................................................................................................................. 43
Hydrograph No. 1, SCS Runoff, Area 1A............................................................................... 43
Hydrograph No. 2, SCS Runoff, Area 1B............................................................................... 44
Hydrograph No. 3, SCS Runoff, Area 1C............................................................................... 45
Hydrograph No. 4, SCS Runoff, Area 2 / Design Pt 2............................................................ 46
Hydrograph No. 5, Reservoir, Basin 1B................................................................................. 47
Hydrograph No. 6, Reservoir, Basin 1C................................................................................. 48
Hydrograph No. 7, Combine, Design Pt 1.............................................................................. 49
IDF Report.................................................................................................................. 50

1 - Area 1A
2 - Area 1B
3 - Area 1C
4 - Area 2 / Design Pt 2
5 - Basin 1B
6 - Basin 1C
7 - Design Pt 1
1
Watershed Model Schematic
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Project: PROP-FINAL 5-21-24.gpw
Tuesday, 05 / 21 / 2024
Hyd. Origin
Description
Legend
1
SCS Runoff
Area 1A
2
SCS Runoff
Area 1B
3
SCS Runoff
Area 1C
4
SCS Runoff
Area 2 / Design Pt 2
5
Reservoir
Basin 1B
6
Reservoir
Basin 1C
7
Combine
Design Pt 1

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
------
-------
5.034
-------
-------
13.65
19.95
24.89
30.39
Area 1A
2
SCS Runoff
------
-------
0.948
-------
-------
2.231
3.120
3.804
4.559
Area 1B
3
SCS Runoff
------
-------
2.288
-------
-------
5.167
7.162
8.707
10.41
Area 1C
4
SCS Runoff
------
-------
0.087
-------
-------
0.289
0.445
0.569
0.710
Area 2 / Design Pt 2
5
Reservoir
2
-------
0.004
-------
-------
0.080
0.116
0.345
0.918
Basin 1B
6
Reservoir
3
-------
0.000
-------
-------
0.036
0.096
0.121
0.145
Basin 1C
7
Combine
1, 5, 6
-------
5.034
-------
-------
13.65
20.00
24.97
30.50
Design Pt 1
Proj. file: PROP-FINAL 5-21-24.gpw
Tuesday, 05 / 21 / 2024
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022

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
5.034
3
747
31,357
------
------
------
Area 1A
2
SCS Runoff
0.948
3
732
4,115
------
------
------
Area 1B
3
SCS Runoff
2.288
3
738
11,726
------
------
------
Area 1C
4
SCS Runoff
0.087
3
735
480
------
------
------
Area 2 / Design Pt 2
5
Reservoir
0.004
3
1449
79
2
128.46
3,743
Basin 1B
6
Reservoir
0.000
3
1143
0
3
125.74
10,540
Basin 1C
7
Combine
5.034
3
747
31,436
1, 5, 6
------
------
Design Pt 1
PROP-FINAL 5-21-24.gpw
Return Period: 2 Year
Tuesday, 05 / 21 / 2024
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Tuesday, 05 / 21 / 2024
Hyd. No. 1
Area 1A
Hydrograph type
=  SCS Runoff
Peak discharge
=  5.034 cfs
Storm frequency
=  2 yrs
Time to peak
=  747 min
Time interval
=  3 min
Hyd. volume
=  31,357 cuft
Drainage area
=  11.900 ac
Curve number
=  65
Basin Slope
=  0.0 %
Hydraulic length
=  0 ft
Tc method
=  TR55
Time of conc. (Tc)
=  30.00 min
Total precip.
=  3.45 in
Distribution
=  Type III
Storm duration
=  24 hrs
Shape factor
=  484
4
0
180
360
540
720
900
1080
1260
1440
1620
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 (min)
Area 1A
Hyd. No. 1 -- 2 Year
Hyd No. 1

TR55 Tc Worksheet
5
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Hyd. No. 1
Area 1A
Description
A
B
C
Totals
Sheet Flow
Manning's n-value
=  0.600
0.011
0.011
Flow length (ft)
=  150.0
0.0
0.0
Two-year 24-hr precip. (in)
=  3.45
0.00
0.00
Land slope (%)
=  5.30
0.00
0.00
Travel Time (min)
= 26.79
+
0.00
+
0.00
=
26.79
Shallow Concentrated Flow
Flow length (ft)
=  908.00
0.00
0.00
Watercourse slope (%)
=  8.40
0.00
0.00
Surface description
=  Unpaved
Unpaved
Unpaved
Average velocity (ft/s)
=4.68
0.00
0.00
Travel Time (min)
= 3.24
+
0.00
+
0.00
=
3.24
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 ..............................................................................
30.00 min

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Tuesday, 05 / 21 / 2024
Hyd. No. 2
Area 1B
Hydrograph type
=  SCS Runoff
Peak discharge
=  0.948 cfs
Storm frequency
=  2 yrs
Time to peak
=  732 min
Time interval
=  3 min
Hyd. volume
=  4,115 cuft
Drainage area
=  1.160 ac
Curve number
=  70
Basin Slope
=  0.0 %
Hydraulic length
=  0 ft
Tc method
=  User
Time of conc. (Tc)
=  10.00 min
Total precip.
=  3.45 in
Distribution
=  Type III
Storm duration
=  24 hrs
Shape factor
=  484
6
0
180
360
540
720
900
1080
1260
1440
1620
Q (cfs)
0.00
0.00
0.10
0.10
0.20
0.20
0.30
0.30
0.40
0.40
0.50
0.50
0.60
0.60
0.70
0.70
0.80
0.80
0.90
0.90
1.00
1.00
Q (cfs)
Time (min)
Area 1B
Hyd. No. 2 -- 2 Year
Hyd No. 2

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Tuesday, 05 / 21 / 2024
Hyd. No. 3
Area 1C
Hydrograph type
=  SCS Runoff
Peak discharge
=  2.288 cfs
Storm frequency
=  2 yrs
Time to peak
=  738 min
Time interval
=  3 min
Hyd. volume
=  11,726 cuft
Drainage area
=  3.210 ac
Curve number
=  71
Basin Slope
=  0.0 %
Hydraulic length
=  0 ft
Tc method
=  TR55
Time of conc. (Tc)
=  22.00 min
Total precip.
=  3.45 in
Distribution
=  Type III
Storm duration
=  24 hrs
Shape factor
=  484
7
0
180
360
540
720
900
1080
1260
1440
1620
Q (cfs)
0.00
0.00
1.00
1.00
2.00
2.00
3.00
3.00
Q (cfs)
Time (min)
Area 1C
Hyd. No. 3 -- 2 Year
Hyd No. 3

TR55 Tc Worksheet
8
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Hyd. No. 3
Area 1C
Description
A
B
C
Totals
Sheet Flow
Manning's n-value
=  0.600
0.011
0.011
Flow length (ft)
=  150.0
0.0
0.0
Two-year 24-hr precip. (in)
=  3.45
0.00
0.00
Land slope (%)
=  9.40
0.00
0.00
Travel Time (min)
= 21.31
+
0.00
+
0.00
=
21.31
Shallow Concentrated Flow
Flow length (ft)
=  131.00
0.00
0.00
Watercourse slope (%)
=  22.90
0.00
0.00
Surface description
=  Unpaved
Unpaved
Unpaved
Average velocity (ft/s)
=7.72
0.00
0.00
Travel Time (min)
= 0.28
+
0.00
+
0.00
=
0.28
Channel Flow
X sectional flow area (sqft)
=  4.50
0.00
0.00
Wetted perimeter (ft)
=  6.70
0.00
0.00
Channel slope (%)
=  5.30
0.00
0.00
Manning's n-value
=  0.030
0.015
0.015
Velocity (ft/s)
=8.76
0.00
0.00
Flow length (ft)
({0})226.0
0.0
0.0
Travel Time (min)
= 0.43
+
0.00
+
0.00
=
0.43
Total Travel Time, Tc ..............................................................................
22.00 min

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Tuesday, 05 / 21 / 2024
Hyd. No. 4
Area 2 / Design Pt 2
Hydrograph type
=  SCS Runoff
Peak discharge
=  0.087 cfs
Storm frequency
=  2 yrs
Time to peak
=  735 min
Time interval
=  3 min
Hyd. volume
=  480 cuft
Drainage area
=  0.240 ac
Curve number
=  61
Basin Slope
=  0.0 %
Hydraulic length
=  0 ft
Tc method
=  TR55
Time of conc. (Tc)
=  13.60 min
Total precip.
=  3.45 in
Distribution
=  Type III
Storm duration
=  24 hrs
Shape factor
=  484
9
0
180
360
540
720
900
1080
1260
1440
1620
Q (cfs)
0.00
0.00
0.01
0.01
0.02
0.02
0.03
0.03
0.04
0.04
0.05
0.05
0.06
0.06
0.07
0.07
0.08
0.08
0.09
0.09
0.10
0.10
Q (cfs)
Time (min)
Area 2 / Design Pt 2
Hyd. No. 4 -- 2 Year
Hyd No. 4

TR55 Tc Worksheet
10
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Hyd. No. 4
Area 2 / Design Pt 2
Description
A
B
C
Totals
Sheet Flow
Manning's n-value
=  0.240
0.011
0.011
Flow length (ft)
=  150.0
0.0
0.0
Two-year 24-hr precip. (in)
=  3.45
0.00
0.00
Land slope (%)
=  4.70
0.00
0.00
Travel Time (min)
= 13.51
+
0.00
+
0.00
=
13.51
Shallow Concentrated Flow
Flow length (ft)
=  14.00
0.00
0.00
Watercourse slope (%)
=  3.60
0.00
0.00
Surface description
=  Unpaved
Unpaved
Unpaved
Average velocity (ft/s)
=3.06
0.00
0.00
Travel Time (min)
= 0.08
+
0.00
+
0.00
=
0.08
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 ..............................................................................
13.60 min

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Tuesday, 05 / 21 / 2024
Hyd. No. 5
Basin 1B
Hydrograph type
=  Reservoir
Peak discharge
=  0.004 cfs
Storm frequency
=  2 yrs
Time to peak
=  1449 min
Time interval
=  3 min
Hyd. volume
=  79 cuft
Inflow hyd. No.
=  2 - Area 1B
Max. Elevation
=  128.46 ft
Reservoir name
=  Basin 1B
Max. Storage
=  3,743 cuft
Storage Indication method used.  Exfiltration extracted from Outflow.
11
0
180
360
540
720
900
1080
1260
1440
1620
1800
Q (cfs)
0.00
0.00
0.10
0.10
0.20
0.20
0.30
0.30
0.40
0.40
0.50
0.50
0.60
0.60
0.70
0.70
0.80
0.80
0.90
0.90
1.00
1.00
Q (cfs)
Time (min)
Basin 1B
Hyd. No. 5 -- 2 Year
Hyd No. 5
Hyd No. 2
Total storage used = 3,743 cuft

Pond Report
12
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Tuesday, 05 / 21 / 2024
Pond No. 1 -  Basin 1B
Pond Data
Contours -User-defined contour areas. Average end area method used for volume calculation. Begining Elevation = 127.00 ft
Stage / Storage Table
Stage (ft)
Elevation (ft)
Contour area (sqft)
Incr. Storage (cuft)
Total storage (cuft)
0.00
127.00
1,711
0
0
1.00
128.00
2,557
2,134
2,134
3.00
130.00
4,433
6,990
9,124
4.00
131.00
5,456
4,945
14,069
4.50
131.50
6,908
3,091
17,160
Culvert / Orifice Structures
Weir Structures
[A]
[B]
[C]
[PrfRsr]
[A]
[B]
[C]
[D]
Rise (in)
=  12.00
2.00
Inactive
Inactive
Span (in)
=  12.00
2.00
4.00
0.00
No. Barrels
=  1
1
1
0
Invert El. (ft)
=  127.00
128.50
129.00
0.00
Length (ft)
=  27.00
1.00
1.00
0.00
Slope (%)
=  3.70
1.00
1.00
n/a
N-Value
=  .013
.013
.013
n/a
Orifice Coeff.
=  0.60
0.60
0.60
0.60
Multi-Stage
=  n/a
Yes
Yes
No
Crest Len (ft)
=  15.00
10.00
Inactive
Inactive
Crest El. (ft)
=  130.00
131.00
0.00
0.00
Weir Coeff.
=  2.60
2.60
3.33
3.33
Weir Type
=  Broad
Broad
---
---
Multi-Stage
=  Yes
No
No
No
Exfil.(in/hr)
=  0.120 (by Contour)
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).
Stage / Storage / Discharge Table
Stage
Storage
Elevation
Clv A
Clv B
Clv C
PrfRsr
Wr A
Wr B
Wr C
Wr D
Exfil
User
Total
ft
cuft
ft
cfs
cfs
cfs
cfs
cfs
cfs
cfs
cfs
cfs
cfs
cfs
0.00
0
127.00
0.00
0.00
0.00
---
0.00
0.00
---
---
0.000
---
0.000
0.10
213
127.10
0.00
0.00
0.00
---
0.00
0.00
---
---
0.001
---
0.001
0.20
427
127.20
0.00
0.00
0.00
---
0.00
0.00
---
---
0.001
---
0.001
0.30
640
127.30
0.00
0.00
0.00
---
0.00
0.00
---
---
0.002
---
0.002
0.40
854
127.40
0.00
0.00
0.00
---
0.00
0.00
---
---
0.003
---
0.003
0.50
1,067
127.50
0.00
0.00
0.00
---
0.00
0.00
---
---
0.004
---
0.004
0.60
1,280
127.60
0.00
0.00
0.00
---
0.00
0.00
---
---
0.004
---
0.004
0.70
1,494
127.70
0.00
0.00
0.00
---
0.00
0.00
---
---
0.005
---
0.005
0.80
1,707
127.80
0.00
0.00
0.00
---
0.00
0.00
---
---
0.006
---
0.006
0.90
1,921
127.90
0.00
0.00
0.00
---
0.00
0.00
---
---
0.006
---
0.006
1.00
2,134
128.00
0.00
0.00
0.00
---
0.00
0.00
---
---
0.007
---
0.007
1.20
2,833
128.20
0.00
0.00
0.00
---
0.00
0.00
---
---
0.008
---
0.008
1.40
3,532
128.40
0.00
0.00
0.00
---
0.00
0.00
---
---
0.008
---
0.008
1.60
4,231
128.60
0.01 ic
0.01 ic
0.00
---
0.00
0.00
---
---
0.009
---
0.023
1.80
4,930
128.80
0.05 ic
0.05 ic
0.00
---
0.00
0.00
---
---
0.009
---
0.058
2.00
5,629
129.00
0.07 ic
0.07 ic
0.00
---
0.00
0.00
---
---
0.010
---
0.078
2.20
6,328
129.20
0.08 ic
0.08 ic
0.00
---
0.00
0.00
---
---
0.010
---
0.093
2.40
7,027
129.40
0.10 ic
0.09 ic
0.00
---
0.00
0.00
---
---
0.011
---
0.106
2.60
7,726
129.60
0.11 ic
0.11 ic
0.00
---
0.00
0.00
---
---
0.011
---
0.117
2.80
8,425
129.80
0.12 ic
0.12 ic
0.00
---
0.00
0.00
---
---
0.012
---
0.128
3.00
9,124
130.00
0.13 ic
0.13 ic
0.00
---
0.00
0.00
---
---
0.012
---
0.137
3.10
9,618
130.10
1.38 ic
0.13 ic
0.00
---
1.23
0.00
---
---
0.013
---
1.375
3.20
10,113
130.20
3.62 ic
0.13 ic
0.00
---
3.49
0.00
---
---
0.013
---
3.635
3.30
10,607
130.30
6.08 ic
0.05 ic
0.00
---
6.03 s
0.00
---
---
0.013
---
6.090
3.40
11,102
130.40
6.34 ic
0.03 ic
0.00
---
6.31 s
0.00
---
---
0.013
---
6.353
3.50
11,596
130.50
6.50 ic
0.02 ic
0.00
---
6.47 s
0.00
---
---
0.014
---
6.507
3.60
12,091
130.60
6.63 ic
0.02 ic
0.00
---
6.60 s
0.00
---
---
0.014
---
6.634
3.70
12,585
130.70
6.74 ic
0.01 ic
0.00
---
6.72 s
0.00
---
---
0.014
---
6.747
3.80
13,080
130.80
6.85 ic
0.01 ic
0.00
---
6.84 s
0.00
---
---
0.015
---
6.864
3.90
13,574
130.90
6.96 ic
0.01 ic
0.00
---
6.95 s
0.00
---
---
0.015
---
6.972
4.00
14,069
131.00
7.07 ic
0.01 ic
0.00
---
7.05 s
0.00
---
---
0.015
---
7.072
4.05
14,378
131.05
7.12 ic
0.01 ic
0.00
---
7.10 s
0.29
---
---
0.016
---
7.417
4.10
14,687
131.10
7.17 ic
0.01 ic
0.00
---
7.13 s
0.82
---
---
0.016
---
7.980
4.15
14,996
131.15
7.22 ic
0.01 ic
0.00
---
7.19 s
1.51
---
---
0.016
---
8.729
4.20
15,305
131.20
7.27 ic
0.01 ic
0.00
---
7.22 s
2.33
---
---
0.017
---
9.567
4.25
15,614
131.25
7.32 ic
0.01 ic
0.00
---
7.31 s
3.25
---
---
0.017
---
10.58
4.30
15,923
131.30
7.37 ic
0.01 ic
0.00
---
7.30 s
4.27
---
---
0.018
---
11.59
4.35
16,232
131.35
7.42 ic
0.01 ic
0.00
---
7.38 s
5.38
---
---
0.018
---
12.79
Continues on next page...

13
Basin 1B
Stage / Storage / Discharge Table
Stage
Storage
Elevation
Clv A
Clv B
Clv C
PrfRsr
Wr A
Wr B
Wr C
Wr D
Exfil
User
Total
ft
cuft
ft
cfs
cfs
cfs
cfs
cfs
cfs
cfs
cfs
cfs
cfs
cfs
4.40
16,541
131.40
7.46 ic
0.01 ic
0.00
---
7.43 s
6.58
---
---
0.018
---
14.03
4.45
16,850
131.45
7.51 ic
0.01 ic
0.00
---
7.45 s
7.85
---
---
0.019
---
15.33
4.50
17,160
131.50
7.56 ic
0.01 ic
0.00
---
7.54 s
9.19
---
---
0.019
---
16.76
...End

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Tuesday, 05 / 21 / 2024
Hyd. No. 6
Basin 1C
Hydrograph type
=  Reservoir
Peak discharge
=  0.000 cfs
Storm frequency
=  2 yrs
Time to peak
=  1143 min
Time interval
=  3 min
Hyd. volume
=  0 cuft
Inflow hyd. No.
=  3 - Area 1C
Max. Elevation
=  125.74 ft
Reservoir name
=  Basin 1C
Max. Storage
=  10,540 cuft
Storage Indication method used.  Exfiltration extracted from Outflow.
14
0
900
1800
2700
3600
4500
5400
6300
7200
8100
9000
Q (cfs)
0.00
0.00
1.00
1.00
2.00
2.00
3.00
3.00
Q (cfs)
Time (min)
Basin 1C
Hyd. No. 6 -- 2 Year
Hyd No. 6
Hyd No. 3
Total storage used = 10,540 cuft

Pond Report
15
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Tuesday, 05 / 21 / 2024
Pond No. 2 -  Basin 1C
Pond Data
Contours -User-defined contour areas. Average end area method used for volume calculation. Begining Elevation = 124.00 ft
Stage / Storage Table
Stage (ft)
Elevation (ft)
Contour area (sqft)
Incr. Storage (cuft)
Total storage (cuft)
0.00
124.00
4,837
0
0
2.00
126.00
7,275
12,112
12,112
4.00
128.00
10,285
17,560
29,672
6.00
130.00
13,566
23,851
53,523
6.50
130.50
15,890
7,364
60,887
Culvert / Orifice Structures
Weir Structures
[A]
[B]
[C]
[PrfRsr]
[A]
[B]
[C]
[D]
Rise (in)
=  12.00
2.00
Inactive
Inactive
Span (in)
=  12.00
2.00
4.00
0.00
No. Barrels
=  1
1
1
0
Invert El. (ft)
=  124.00
127.00
128.00
0.00
Length (ft)
=  45.00
1.00
1.00
0.00
Slope (%)
=  1.10
1.00
1.00
n/a
N-Value
=  .013
.013
.013
n/a
Orifice Coeff.
=  0.60
0.60
0.60
0.60
Multi-Stage
=  n/a
Yes
Yes
No
Crest Len (ft)
=  15.00
10.00
Inactive
Inactive
Crest El. (ft)
=  129.00
130.00
0.00
0.00
Weir Coeff.
=  2.60
2.60
3.33
3.33
Weir Type
=  Broad
Broad
---
---
Multi-Stage
=  Yes
No
No
No
Exfil.(in/hr)
=  0.220 (by Contour)
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).
Stage / Storage / Discharge Table
Stage
Storage
Elevation
Clv A
Clv B
Clv C
PrfRsr
Wr A
Wr B
Wr C
Wr D
Exfil
User
Total
ft
cuft
ft
cfs
cfs
cfs
cfs
cfs
cfs
cfs
cfs
cfs
cfs
cfs
0.00
0
124.00
0.00
0.00
0.00
---
0.00
0.00
---
---
0.000
---
0.000
0.20
1,211
124.20
0.00
0.00
0.00
---
0.00
0.00
---
---
0.004
---
0.004
0.40
2,422
124.40
0.00
0.00
0.00
---
0.00
0.00
---
---
0.007
---
0.007
0.60
3,634
124.60
0.00
0.00
0.00
---
0.00
0.00
---
---
0.011
---
0.011
0.80
4,845
124.80
0.00
0.00
0.00
---
0.00
0.00
---
---
0.015
---
0.015
1.00
6,056
125.00
0.00
0.00
0.00
---
0.00
0.00
---
---
0.019
---
0.019
1.20
7,267
125.20
0.00
0.00
0.00
---
0.00
0.00
---
---
0.022
---
0.022
1.40
8,478
125.40
0.00
0.00
0.00
---
0.00
0.00
---
---
0.026
---
0.026
1.60
9,690
125.60
0.00
0.00
0.00
---
0.00
0.00
---
---
0.030
---
0.030
1.80
10,901
125.80
0.00
0.00
0.00
---
0.00
0.00
---
---
0.033
---
0.033
2.00
12,112
126.00
0.00
0.00
0.00
---
0.00
0.00
---
---
0.037
---
0.037
2.20
13,868
126.20
0.00
0.00
0.00
---
0.00
0.00
---
---
0.039
---
0.039
2.40
15,624
126.40
0.00
0.00
0.00
---
0.00
0.00
---
---
0.040
---
0.040
2.60
17,380
126.60
0.00
0.00
0.00
---
0.00
0.00
---
---
0.042
---
0.042
2.80
19,136
126.80
0.00
0.00
0.00
---
0.00
0.00
---
---
0.043
---
0.043
3.00
20,892
127.00
0.00
0.00
0.00
---
0.00
0.00
---
---
0.045
---
0.045
3.20
22,648
127.20
0.04 ic
0.04 ic
0.00
---
0.00
0.00
---
---
0.046
---
0.082
3.40
24,404
127.40
0.06 ic
0.06 ic
0.00
---
0.00
0.00
---
---
0.048
---
0.107
3.60
26,160
127.60
0.08 ic
0.08 ic
0.00
---
0.00
0.00
---
---
0.049
---
0.125
3.80
27,916
127.80
0.09 ic
0.09 ic
0.00
---
0.00
0.00
---
---
0.051
---
0.140
4.00
29,672
128.00
0.11 ic
0.10 ic
0.00
---
0.00
0.00
---
---
0.052
---
0.153
4.20
32,057
128.20
0.11 ic
0.11 ic
0.00
---
0.00
0.00
---
---
0.054
---
0.165
4.40
34,442
128.40
0.12 ic
0.12 ic
0.00
---
0.00
0.00
---
---
0.056
---
0.176
4.60
36,827
128.60
0.13 ic
0.13 ic
0.00
---
0.00
0.00
---
---
0.057
---
0.187
4.80
39,212
128.80
0.14 ic
0.14 ic
0.00
---
0.00
0.00
---
---
0.059
---
0.197
5.00
41,598
129.00
0.15 ic
0.15 ic
0.00
---
0.00
0.00
---
---
0.061
---
0.206
5.20
43,983
129.20
3.64 oc
0.15 ic
0.00
---
3.49
0.00
---
---
0.062
---
3.703
5.40
46,368
129.40
8.05 oc
0.04 ic
0.00
---
8.00 s
0.00
---
---
0.064
---
8.111
5.60
48,753
129.60
8.32 oc
0.02 ic
0.00
---
8.29 s
0.00
---
---
0.066
---
8.382
5.80
51,138
129.80
8.50 oc
0.02 ic
0.00
---
8.48 s
0.00
---
---
0.067
---
8.566
6.00
53,523
130.00
8.67 oc
0.01 ic
0.00
---
8.65 s
0.00
---
---
0.069
---
8.734
6.05
54,259
130.05
8.71 oc
0.01 ic
0.00
---
8.70 s
0.29
---
---
0.070
---
9.074
6.10
54,996
130.10
8.75 oc
0.01 ic
0.00
---
8.73 s
0.82
---
---
0.071
---
9.633
6.15
55,732
130.15
8.79 oc
0.01 ic
0.00
---
8.75 s
1.51
---
---
0.073
---
10.34
6.20
56,469
130.20
8.83 oc
0.01 ic
0.00
---
8.81 s
2.33
---
---
0.074
---
11.22
6.25
57,205
130.25
8.87 oc
0.01 ic
0.00
---
8.82 s
3.25
---
---
0.075
---
12.16
6.30
57,941
130.30
8.91 oc
0.01 ic
0.00
---
8.87 s
4.27
---
---
0.076
---
13.22
6.35
58,678
130.35
8.95 oc
0.01 ic
0.00
---
8.92 s
5.38
---
---
0.077
---
14.39
Continues on next page...

16
Basin 1C
Stage / Storage / Discharge Table
Stage
Storage
Elevation
Clv A
Clv B
Clv C
PrfRsr
Wr A
Wr B
Wr C
Wr D
Exfil
User
Total
ft
cuft
ft
cfs
cfs
cfs
cfs
cfs
cfs
cfs
cfs
cfs
cfs
cfs
6.40
59,414
130.40
8.99 oc
0.01 ic
0.00
---
8.98 s
6.58
---
---
0.079
---
15.64
6.45
60,151
130.45
9.03 oc
0.01 ic
0.00
---
9.00 s
7.85
---
---
0.080
---
16.94
6.50
60,887
130.50
9.07 oc
0.01 ic
0.00
---
9.03 s
9.19
---
---
0.081
---
18.31
...End

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2022
Tuesday, 05 / 21 / 2024
Hyd. No. 7
Design Pt 1
Hydrograph type
=  Combine
Peak discharge
=  5.034 cfs
Storm frequency
=  2 yrs
Time to peak
=  747 min
Time interval
=  3 min
Hyd. volume
=  31,436 cuft
Inflow hyds.
=  1, 5, 6
Contrib. drain. area
=  11.900 ac
17
0
180
360
540
720
900
1080
1260
1440
1620
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 (min)
Design Pt 1
Hyd. No. 7 -- 2 Year
Hyd No. 7
Hyd No. 1
Hyd No. 5
Hyd No. 6

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
13.65
3
741
74,898
------
------
------
Area 1A
2
SCS Runoff
2.231
3
729
8,951
------
------
------
Area 1B
3
SCS Runoff
5.167
3
738
25,081
------
------
------
Area 1C
4
SCS Runoff
0.289
3
732
1,256
------
------
------
Area 2 / Design Pt 2
5
Reservoir
0.080
3
1029
4,337
2
129.17
6,207
Basin 1B
6
Reservoir
0.036
3
1449
981
3
127.20
22,651
Basin 1C
7
Combine
13.65
3
741
80,216
1, 5, 6
------
------
Design Pt 1
PROP-FINAL 5-21-24.gpw
Return P