Conservation Commission - 185 (03/09/2023)

Storm Drainage Report 
Proposed Affordable Housing Development 
Clark Lane 
Waterford, Connecticut 
 
 
 
Prepared for 
 
Kingstown Properties LLC 
 
 
 
October 10, 2022 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Prepared by: 
 
Provost & Rovero, Inc.
Provost & Rovero, Inc.
Provost & Rovero, Inc.
Provost & Rovero, Inc. 

Table of Contents 
Section 1 – Executive Summary 
Section 2 – Storm Sewer Design Calculations 
Section 3 – Water Quality Design Calculations 
Section 4 – Hydrologic Analysis Calculations 
Section 5 – Erosion and Sediment Control Design 

 
 
 
 
 
 
Section 1 
Executive Summary 
 

PROJECT NARRATIVE 
 
This proposal involves the construction of 47 detached affordable housing units on a 16.166 acre 
parcel located on the easterly side of Clark Lane in Waterford, Connecticut.  The project will be 
accessed by a private road system which intersects Clark Lane at the northerly and southerly 
limits of the project.  All units will be served by public water and sewer utilities.  The project is 
located in the watershed of the Fenger Brook headwaters which is a tributary within the Jordan 
Brook watershed.  The subject property is comprised primarily of hydrologic group C soils of the 
Montauk series.  The property generally slopes and drains from west to east and Fenger Brook 
flows off the property near its southeasterly corner.  The southeasterly portion of the subject 
property includes a wetland system which extends approximately 500’ up gradient of the Fenger 
Brook watercourse.  Because of the environmental sensitivity of the overall Jordan Brook 
watershed, the project has been designed to provide a minimum 50’ undisturbed buffer to the 
delineated wetland edge.  The only exception to this buffer is the discharge from the stormwater 
treatment and management system which will discharge fully renovated and treated stormwater 
near the wetland edge.  Stormwater management and treatment will be accomplished by means of 
a system which includes catch basin sumps, a hydrodynamic separator, a bioretention basin and a 
stormwater detention basin. 
 
HYDROLOGIC ANALYSIS 
 
This project includes a stormwater detention basin to mitigate increases in peak flow rates 
resulting from the proposed development.  A hydrologic analysis point was chosen where Fenger 
Brook leaves the subject property near its southeasterly corner.  The overall watershed at this 
point is approximately 102 acres.  The hydrologic analysis was completed with HydroCAD 
software utilizing TR-55 and TR-20 methodology.  The following is a summary of existing and 
proposed peak flow rates at the analysis point: 
 
Storm Event 
 
Existing Peak Flow (cfs) 
Proposed Peak Flow (cfs) 
2 year  
 
 
47.88  
 
 
41.18 
5 year  
 
 
81.00  
 
 
70.03 
10 year  
 
 
102.16  
 
 
88.62 
25 year  
 
 
131.32  
 
 
122.95 
50 year  
 
 
153.86  
 
 
151.05 
100 year 
 
 
184.45  
 
 
184.22 
 
The following is a summary of proposed peak flow rates at the detention basin discharge: 
 
Storm Event 
 
Proposed Peak Flow (cfs) 
2 year  
 
 
2.93 
 
 
 
 
5 year  
 
 
3.69 
 
 
 
 
10 year  
 
 
6.61 
 
 
 
 
25 year  
 
 
15.15  
 
 
 
50 year  
 
 
22.04  
 
 
 
100 year 
 
 
28.85  
 
 
 
 
 
The detention basin outlet is equipped with a riprap lined plunge pool and concrete weir level 
spreader.  The discharge from the detention basin during a 100 year storm was analyzed to ensure 
that the level spreader would not result in erosive flow velocities.  The 100 year detention basin 
discharge is 28.85 cfs which will result in a flow velocity from the level spreader of 1.78 ft/sec.  

Per the 2002 Connecticut Guidelines for Soil Erosion and Sediment Control, the allowable 
velocity for sandy loam soils consistent with those observed on site is 2.5 ft/sec.  Based on this 
analysis, downstream erosion of native soils is not anticipated as a result of the detention basin 
discharge. 
 
Detailed hydrologic calculations are presented in Section 4. 
 
WATER QUALITY DESIGN 
 
This project incorporates multiple stacked stormwater treatment measures to mitigate any 
potential impacts to stormwater quality.  The stormwater quality treatment system has also been 
sized to fully renovate and treat off-site stormwater runoff from Clark Lane which currently 
discharges onto the subject property.  The system has primarily been designed to address loading 
of the following pollutants: total nitrogen, total phosphorus, total suspended solids (sediment) and 
heavy metals.  The control of sediment transport is important in mitigating all of the pollutants 
due to the tendency of these pollutants to adhere to sediment.  Bacteriological pollutant loading is 
not considered a primary concern for this project because of the use of sanitary sewers to dispose 
of all wastewater.  The following measures are incorporated into the stormwater treatment 
system: 
 
• 
Catch basins equipped with sumps for retention of solids. 
• 
Stormceptor hydrodynamic separator – designed to capture 80% of total suspended solids 
(TSS) annually for sediment gradation consistent with road sand.  Suspended solids are a 
primary source of potential pollution including nitrogen, phosphorus and heavy metals.  
Field testing of in place Stormceptor units has indicated removal efficiencies of 
approximately 65% for total nitrogen and 30% for total phosphorus. 
• 
Bioretention basin – design per 2008 New Hampshire Stormwater Manual (“NH 
Manual”) and 2004 Connecticut Stormwater Quality Manual (“CT Manual”) to treat the 
water quality volume (WQV) from the proposed project and Clark Lane.  The NH 
Manual indicates a 90% removal efficiency for total suspended solids, a 65% removal 
efficiency for total nitrogen and a 65% removal efficiency for total phosphorus.  The 
bioretention basin has been designed as an off-line system through the use of a flow 
diversion structure.  The diversion structure has been designed to minimize flow rates 
through the basin above the water quality flow (WQF) even during large storm events.  
• 
Wet bottom detention basin – based on test pits within the detention basin, a permanent 
hydric soil regime is anticipated.  Initial seeding and natural colonization of wetland 
species will facilitate additional vegetative stormwater renovation. 
 
While the overall performance of the proposed stormwater treatment train cannot be exactly 
quantified, the stacking of different measures will significantly increase discharged water quality 
versus reliance on a single treatment measure.  The stacking of different measures is encouraged 
in Section 6.4 of the CT Manual.  While the NH Manual conservatively allows a designer to only 
account for the most effective measure within the treatment train, accounting for the removal 
efficiencies of just the Stormceptor and biorentention basin would result in the following 
estimated removal efficiencies for any discharges into the receiving environment: 
 
Total Suspended Solids: 98% removal  
Total Nitrogen: 88% removal 
Total Phosphorus: 75% removal 
 

Design calculations for specific water quality treatment systems are presented in Section 3. 
 
STORM SEWER DESIGN 
 
Storm sewers will be constructed of smooth interior wall HDPE pipe.  The hydrologic analysis 
for storm sewer design was completed with the Rational Method for a 10 year design storm 
utilizing IDF information from the Connecticut DOT Drainage Manual. 
 
Storm sewer design calculations are presented in Section 2. 
 
TEMPORARY EROSION AND SEDIMENTATION CONTROL DESIGN 
 
The total disturbed area proposed for this project is approximately 8 acres.  A temporary sediment 
basin has been designed to accommodate this site disturbance with an assumed project duration of 
18 months based on sediment loading capacity.  The sediment basin has been designed to allow 
reconfiguring into both the permanent bioretention basin and detention basin.  The bioretention 
basin reconfiguration will require the placement of fill in the bottom of the basin and the 
installation of the underdrain and sand/compost filter system as well as permanent stabilization 
with the selected seed mix and wetland plantings.  The detention basin reconfiguration will only 
require minor modifications to the outlet structure, provisions for which can be incorporated into 
the initial sediment basin construction.   
 
The sediment basin has been designed in accordance with the 2002 Connecticut Guidelines for 
Soil Erosion and Sediment Control.  Storm routing and design of the outlet control system were 
accomplished with TR-55 and TR-20 methodology utilizing HydroCAD software.  Design 
calculations for the sediment basin are presented in Section 5. 
 
Because the sediment basin will serve the majority of the disturbed site area, isolated perimeter 
site areas which cannot drain to the sediment basin can be suitably protected with non-engineered 
erosion and sediment controls such as silt fence, staked hay bales, wood chip berms, temporary 
seeding and management of site grades to prevent concentrated flows. 
 
 

 
 
 
 
 
Section 2 
Storm Sewer Design Calculations 
 



 
 
 
 
 
Section 3 
Water Quality Design Calculations 
 

Project Information & Location
Project Name
Clark Lane
Project Number
213009
City
Waterford
State/ Province
Connecticut
Country
United States of America
Date
5/15/2022
 Designer Information
EOR Information (optional)
Name
David Held
Name
 
Company
Provost & Rovero, Inc.
Company
Phone #
860-230-0856
Phone #
Email
dheld@prorovinc.com
Email
The recommended Stormceptor Model(s) which achieve or exceed the user defined water quality objective for each site 
within the project are listed in the below Sizing Summary table.
Site Name
Clark Lane
Recommended Stormceptor Model
STC 4800
Target TSS Removal (%)
80.0
TSS Removal (%) Provided
81
PSD
OK-110
Rainfall Station
BRIDGEPORT SIKORSKY AP 
The recommended Stormceptor model achieves the water quality objectives based on the selected 
inputs, historical rainfall records and selected particle size distribution.
Detailed Stormceptor Sizing Report ±Clark Lane
Stormceptor Sizing Summary
Stormceptor Model
% TSS Removal 
Provided
STC 450i
59
STC 900
70
STC 1200
70
STC 1800
71
STC 2400
76
STC 3600
77
STC 4800
81
STC 6000
81
STC 7200
84
STC 11000
88
STC 13000
88
STC 16000
90
Stormwater Treatment Recommendation
Detailed Sizing Report ±Page 1 of 8
Stormceptor

Notes
‡Stormceptor performance estimates are based on simulations using PCSWMM for Stormceptor, which uses the EPA Rainfall and 
Runoff modules.
‡Design estimates listed are only representative of specific project requirements based on total suspended solids (TSS) removal 
defined by the selected PSD, and based on stable site conditions only, after construction is completed.
‡For submerged applications or sites specific to spill control, please contact your local Stormceptor representative for further design 
assistance.
Hydrology Analysis
PCSWMM for Stormceptor calculates annual hydrology with the US EPA SWMM and local continuous historical rainfall data. 
Performance calculations of Stormceptor are based on the average annual removal of TSS for the selected site parameters. The 
Stormceptor is engineered to capture sediment particles by treating the required average annual runoff volume, ensuring positive 
removal efficiency is maintained during each rainfall event, and preventing negative removal efficiency (scour).
Smaller recurring storms account for the majority of rainfall events and average annual runoff volume, as observed in the historical 
rainfall data analyses presented in this section.
Rainfall Station
State/Province
Connecticut
Total Number of Rainfall Events
7592
Rainfall Station Name
BRIDGEPORT SIKORSKY 
AP
Total Rainfall (in)
2372.0
Station ID #
0806
Average Annual Rainfall (in)
40.9
Coordinates
41°9'30"N, 73°7'44"W
Total Evaporation (in)
87.8
Elevation (ft)
5
Total Infiltration (in)
1437.7
Years of Rainfall Data
58
Total Rainfall that is Runoff (in)
846.5
Stormceptor
The Stormceptor oil and sediment separator is sized to treat stormwater runoff by removing pollutants through gravity 
separation and flotation. Stormceptor¶s patented design generates positive TSS removal for each rainfall event, including 
large storms. Significant levels of pollutants such as heavy metals, free oils and nutrients are prevented from entering 
natural water resources and the re-suspension of previously captured sediment (scour) does not occur. 
Stormceptor provides a high level of TSS removal for small frequent storm events that represent the majority of annual 
rainfall volume and pollutant load. Positive treatment continues for large infrequent events, however, such events have 
little impact on the average annual TSS removal as they represent a small percentage of the total runoff volume and 
pollutant load. 
Design Methodology 
Stormceptor is sized using PCSWMM for Stormceptor, a continuous simulation model based on US EPA SWMM. The 
program calculates hydrology using local historical rainfall data and specified site parameters. With US EPA SWMM¶s 
precision, every Stormceptor unit is designed to achieve a defined water quality objective. The TSS removal data 
presented follows US EPA guidelines to reduce the average annual TSS load. The Stormceptor¶s unit process for TSS 
removal is settling. The settling model calculates TSS removal by analyzing: 
‡Site parameters 
‡Continuous historical rainfall data, including duration, distribution, peaks & inter-event dry periods 
‡Particle size distribution, and associated settling velocities (Stokes Law, corrected for drag) 
‡TSS load 
‡Detention time of the system
Detailed Sizing Report ±Page 2 of 8
Stormceptor

Drainage Area
Total Area (acres)
13.74
Imperviousness %
38.5
Water Quality Objective
TSS Removal (%)
80.0
Runoff Volume Capture (%)
Oil Spill Capture Volume (Gal)
Peak Conveyed Flow Rate (CFS)
Water Quality Flow Rate (CFS)
Design Details
Stormceptor Inlet Invert Elev (ft)
96.30
Stormceptor Outlet Invert Elev (ft)
96.30
Stormceptor Rim Elev (ft)
Normal Water Level Elevation (ft)
Pipe Diameter (in)
24
Pipe Material
HDPE - plastic
Multiple Inlets (Y/N)
Yes
Grate Inlet (Y/N)
No
Particle Size Distribution (PSD)
Removing the smallest fraction of particulates from runoff ensures the majority of pollutants, such as 
metals, hydrocarbons and nutrients are captured. The table below identifies the Particle Size 
Distribution (PSD) that was selected to define TSS removal for the Stormceptor design.
OK-110
Particle Diameter
(microns)
Distribution 
%
Specific Gravity
1.0
0.0
2.65
53.0
3.0
2.65
75.0
15.0
2.65
88.0
25.0
2.65
106.0
41.0
2.65
125.0
15.0
2.65
150.0
1.0
2.65
212.0
0.0
2.65
Up Stream Storage
Storage (ac-ft)
Discharge (cfs)
0.000
0.000
Up Stream Flow Diversion
Max. Flow to Stormceptor (cfs)
Detailed Sizing Report ±Page 3 of 8
Stormceptor

Site Name
Clark Lane
Site Details
Drainage Area
Total Area (acres)
13.74
Imperviousness %
38.5
Infiltration Parameters
Horton¶s equation is used to estimate infiltration
Max. Infiltration Rate (in/hr)
2.44
Min. Infiltration Rate (in/hr)
0.4
Decay Rate (1/sec)
0.00055
Regeneration Rate (1/sec)
0.01
Surface Characteristics
Width (ft)
1547.00
Slope %
2
Impervious Depression Storage (in)
0.02
Pervious Depression Storage (in)
0.2
Impervious Manning¶s n
0.015
Pervious Manning¶s n
0.25
Evaporation
Daily Evaporation Rate (in/day)
0.1
Dry Weather Flow
Dry Weather Flow (cfs)
0
Maintenance Frequency
Maintenance Frequency (months) >
12
Winter Months
Winter Infiltration
0
TSS Loading Parameters
TSS Loading Function
Buildup/Wash-off Parameters
Target Event Mean Conc. (EMC) mg/L 
Exponential Buildup Power
Exponential Washoff Exponent
TSS Availability Parameters
Availability Constant A
Availability Factor B
Availability Exponent C
Min. Particle Size Affected by Availability 
(micron)
Detailed Sizing Report ±Page 4 of 8
Stormceptor

Cumulative Runoff  Volume by Runoff Rate
Runoff Rate (cfs)
Runoff Volume (ft³)
Volume Over (ft³)
Cumulative Runoff Volume 
(%)
0.035
3542487
39932370
8.2
0.141
9164891
34302280
21.1
0.318
14570120
28888310
33.5
0.565
19383870
24080850
44.6
0.883
23548900
19906010
54.2
1.271
27064450
16405460
62.3
1.730
29997260
13467140
69.0
2.260
32409850
11051820
74.6
2.860
34426600
9037395
79.2
3.531
36079020
7385202
83.0
4.273
37425120
6034767
86.1
5.085
38522150
4939094
88.6
5.968
39401380
4058374
90.7
6.922
40115140
3345436
92.3
7.946
40684690
2775470
93.6
9.041
41148840
2310718
94.7
10.206
41525630
1933773
95.6
11.442
41831030
1628381
96.3
12.749
42082410
1376671
96.8
14.126
42294880
1164317
97.3
15.574
42472560
986484
97.7
17.092
42621690
837396
98.1
18.681
42748810
710346
98.4
20.341
42851960
607109
98.6
22.072
42937830
521210
98.8
23.873
43013870
445008
99.0
25.744
43078770
380114
99.1
27.687
43134350
324578
99.3
29.700
43182370
276615
99.4
31.783
43222220
236770
99.5
33.937
43257010
201963
99.5
36.162
43285180
173804
99.6
38.458
43309860
149113
99.7
40.824
43332990
125978
99.7
43.261
43353620
105317
99.8
45.768
43371190
87741
99.8
48.346
43386000
72897
99.8
Detailed Sizing Report ±Page 5 of 8
Stormceptor

50.994
43399360
59516
99.9
53.714
43411060
47816
99.9
56.504
43418970
39897
99.9
Detailed Sizing Report ±Page 6 of 8
Stormceptor

Rainfall Event Analysis
Rainfall Depth (in)
No. of Events
Percentage of Total 
Events (%)
Total Volume (in)
Percentage of Annual 
Volume (%)
0.25
5078
66.9
361
15.2
0.50
1071
14.1
394
16.6
0.75
510
6.7
314
13.2
1.00
324
4.3
285
12.0
1.25
224
3.0
251
10.6
1.50
132
1.7
182
7.7
1.75
73
1.0
118
5.0
2.00
54
0.7
101
4.2
2.25
32
0.4
68
2.9
2.50
26
0.3
61
2.6
2.75
18
0.2
47
2.0
3.00
10
0.1
29
1.2
3.25
8
0.1
25
1.0
3.50
8
0.1
27
1.2
3.75
8
0.1
29
1.2
4.00
3
0.0
12
0.5
4.25
2
0.0
8
0.3
4.50
2
0.0
9
0.4
4.75
2
0.0
9
0.4
5.00
0
0.0
0
0.0
5.25
1
0.0
5
0.2
5.50
2
0.0
11
0.4
5.75
0
0.0
0
0.0
6.00
1
0.0
6
0.2
6.25
0
0.0
0
0.0
6.50
2
0.0
13
0.5
6.75
0
0.0
0
0.0
7.00
0
0.0
0
0.0
7.25
1
0.0
7
0.3
7.50
0
0.0
0
0.0
7.75
0
0.0
0
0.0
Detailed Sizing Report ±Page 7 of 8
Stormceptor

For Stormceptor Specifications and Drawings Please Visit: 
https://www.conteches.com/technical-guides/search?filter=1WBC0O5EYX
Detailed Sizing Report ±Page 8 of 8
Stormceptor






Water Quality Diversion Structure Design
water quality flow (WGF)
top of diversion weir

 
 
 
 
 
Section 4 
Hydrologic Analysis Calculations 
 

57 EAST MAIN ST. P.O. BOX 191, PLAINFIELD, CT. 

57 EAST MAIN ST. P.O. BOX 191, PLAINFIELD, CT. 

1S
P-1
2S
P-2
3S
E-1
3R
Overland Flow
6P
Detention Basin
2L
Design Point
Routing Diagram for 213009
Prepared by Provost & Rovero, Inc.,  Printed 3/9/2022
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Subcat
Reach
Pond
Link

213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 2
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Project Notes
CarlsonStageIncrement|1.0000|

213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 3
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Area Listing (all nodes)
Area
(acres)
CN
Description
(subcatchment-numbers)
21.549
49
50-75% Grass cover, Fair HSG A  (1S, 3S)
6.976
69
50-75% Grass cover, Fair HSG B  (1S, 3S)
46.790
79
50-75% Grass cover, Fair HSG C  (1S, 2S, 3S)
1.996
84
50-75% Grass cover, Fair HSG D  (1S, 3S)
22.152
98
Paved parking HSG A  (1S, 3S)
1.644
98
Paved parking HSG B  (1S, 3S)
19.305
98
Paved parking HSG C  (1S, 2S, 3S)
1.046
98
Paved parking HSG D  (1S, 3S)
7.008
36
Woods, Fair HSG A  (1S, 3S)
7.864
60
Woods, Fair HSG B  (1S, 3S)
41.589
73
Woods, Fair HSG C  (1S, 2S, 3S)
21.166
79
Woods, Fair HSG D  (1S, 3S)
3.956
76
Woods/grass comb., Fair HSG C  (1S, 2S, 3S)
0.402
82
Woods/grass comb., Fair HSG D  (1S, 3S)
203.443
76
TOTAL AREA

213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 4
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Soil Listing (all nodes)
Area
(acres)
Soil
Group
Subcatchment
Numbers
50.709
HSG A
1S, 3S
16.484
HSG B
1S, 3S
111.640
HSG C
1S, 2S, 3S
24.610
HSG D
1S, 3S
0.000
Other
203.443
TOTAL AREA

213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 5
HydroCAD® 10.00-13  s/n 02606  © 2014 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
21.549
6.976
46.790
1.996
0.000
77.311
50-75% Grass cover, Fair 1S, 2S, 
3S
22.152
1.644
19.305
1.046
0.000
44.147
Paved parking
1S, 2S, 
3S
7.008
7.864
41.589
21.166
0.000
77.627
Woods, Fair
1S, 2S, 
3S
0.000
0.000
3.956
0.402
0.000
4.358
Woods/grass comb., Fair
1S, 2S, 
3S
50.709
16.484
111.640
24.610
0.000
203.443
TOTAL AREA

213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 6
HydroCAD® 10.00-13  s/n 02606  © 2014 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
6P
89.00
88.00
112.0
0.0089
0.012
24.0
0.0
0.0
2
6P
90.00
89.90
5.0
0.0200
0.012
10.0
0.0
0.0

Type III 24-hr  2 year Rainfall=3.20"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 7
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Time span=0.00-24.00 hrs, dt=0.01 hrs, 2401 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Muskingum-Cunge method  -  Pond routing by Stor-Ind method
Runoff Area=87.970 ac   20.82% Impervious   Runoff Depth>1.07"
Subcatchment 1S: P-1
   Flow Length=4,420'   Tc=68.3 min   CN=75   Runoff=38.95 cfs  7.866 af
Runoff Area=13.736 ac   38.54% Impervious   Runoff Depth>1.83"
Subcatchment 2S: P-2
   Tc=26.0 min   CN=86   Runoff=17.80 cfs  2.090 af
Runoff Area=101.737 ac   20.18% Impervious   Runoff Depth>1.13"
Subcatchment 3S: E-1
   Flow Length=4,420'   Tc=68.3 min   CN=76   Runoff=47.88 cfs  9.584 af
Avg. Flow Depth=0.15'   Max Vel=0.42 fps   Inflow=2.93 cfs  1.902 af
Reach 3R: Overland Flow
n=0.400   L=760.0'   S=0.0368 '/'   Capacity=35.52 cfs   Outflow=2.93 cfs  1.873 af
Peak Elev=92.42'  Storage=44,281 cf   Inflow=17.80 cfs  2.090 af
Pond 6P: Detention Basin
   Outflow=2.93 cfs  1.902 af
   Inflow=41.18 cfs  9.739 af
Link 2L: Design Point
   Primary=41.18 cfs  9.739 af
Total Runoff Area = 203.443 ac   Runoff Volume = 19.540 af   Average Runoff Depth = 1.15"
78.30% Pervious = 159.296 ac     21.70% Impervious = 44.147 ac

Type III 24-hr  2 year Rainfall=3.20"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 8
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Summary for Subcatchment 1S: P-1
CarlsonPlanXYPos|1171180.9301|691042.4469|
CarlsonSurface||
Runoff
=
38.95 cfs @ 12.98 hrs,  Volume=
7.866 af,  Depth> 1.07"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs
Type III 24-hr  2 year Rainfall=3.20"
Area (ac)
CN
Description
11.076
98
Paved parking HSG A
10.583
79
Woods, Fair HSG D
1.449
76
Woods/grass comb., Fair HSG C
0.201
82
Woods/grass comb., Fair HSG D
3.504
36
Woods, Fair HSG A
16.559
73
Woods, Fair HSG C
3.932
60
Woods, Fair HSG B
0.822
98
Paved parking HSG B
0.523
98
Paved parking HSG D
5.898
98
Paved parking HSG C
10.774
49
50-75% Grass cover, Fair HSG A
3.488
69
50-75% Grass cover, Fair HSG B
18.163
79
50-75% Grass cover, Fair HSG C
0.998
84
50-75% Grass cover, Fair HSG D
87.970
75
Weighted Average
69.651
79.18% Pervious Area
18.319
20.82% Impervious Area
Tc
Length
Slope
Velocity
Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
14.3
100
0.0200
0.12
Sheet Flow, 
Grass: Dense   n= 0.240   P2= 3.20"
3.6
980
0.0490
4.49
Shallow Concentrated Flow, 
Paved   Kv= 20.3 fps
6.8
1,230
3.00
Direct Entry, pipe flow
43.6
2,110
0.0260
0.81
Shallow Concentrated Flow, 
Woodland   Kv= 5.0 fps
68.3
4,420
Total

Type III 24-hr  2 year Rainfall=3.20"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 9
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Subcatchment 1S: P-1
Runoff
Hydrograph
Time  (hours)
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Flow  (cfs)
42
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Type III 24-hr
2 year Rainfall=3.20"
Runoff Area=87.970 ac
Runoff Volume=7.866 af
Runoff Depth>1.07"
Flow Length=4,420'
Tc=68.3 min
CN=75
38.95 cfs

Type III 24-hr  2 year Rainfall=3.20"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 10
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Summary for Subcatchment 2S: P-2
CarlsonPlanXYPos|1170813.5231|690121.8114|
CarlsonSurface||
Runoff
=
17.80 cfs @ 12.36 hrs,  Volume=
2.090 af,  Depth> 1.83"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs
Type III 24-hr  2 year Rainfall=3.20"
Area (ac)
CN
Description
0.464
73
Woods, Fair HSG C
0.525
76
Woods/grass comb., Fair HSG C
5.294
98
Paved parking HSG C
7.453
79
50-75% Grass cover, Fair HSG C
13.736
86
Weighted Average
8.442
61.46% Pervious Area
5.294
38.54% Impervious Area
Tc
Length
Slope
Velocity
Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
26.0
Direct Entry, Storm sewer TC
Subcatchment 2S: P-2
Runoff
Hydrograph
Time  (hours)
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Flow  (cfs)
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Type III 24-hr
2 year Rainfall=3.20"
Runoff Area=13.736 ac
Runoff Volume=2.090 af
Runoff Depth>1.83"
Tc=26.0 min
CN=86
17.80 cfs

Type III 24-hr  2 year Rainfall=3.20"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 11
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Summary for Subcatchment 3S: E-1
CarlsonPlanXYPos|1171180.9301|691042.4469|
CarlsonSurface||
Runoff
=
47.88 cfs @ 12.98 hrs,  Volume=
9.584 af,  Depth> 1.13"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs
Type III 24-hr  2 year Rainfall=3.20"
Area (ac)
CN
Description
11.076
98
Paved parking HSG A
10.583
79
Woods, Fair HSG D
1.982
76
Woods/grass comb., Fair HSG C
0.201
82
Woods/grass comb., Fair HSG D
3.504
36
Woods, Fair HSG A
24.566
73
Woods, Fair HSG C
3.932
60
Woods, Fair HSG B
0.822
98
Paved parking HSG B
0.523
98
Paved parking HSG D
8.113
98
Paved parking HSG C
10.775
49
50-75% Grass cover, Fair HSG A
3.488
69
50-75% Grass cover, Fair HSG B
21.174
79
50-75% Grass cover, Fair HSG C
0.998
84
50-75% Grass cover, Fair HSG D
101.737
76
Weighted Average
81.203
79.82% Pervious Area
20.534
20.18% Impervious Area
Tc
Length
Slope
Velocity
Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
14.3
100
0.0200
0.12
Sheet Flow, 
Grass: Dense   n= 0.240   P2= 3.20"
3.6
980
0.0490
4.49
Shallow Concentrated Flow, 
Paved   Kv= 20.3 fps
6.8
1,230
3.00
Direct Entry, pipe flow
43.6
2,110
0.0260
0.81
Shallow Concentrated Flow, watercourse
Woodland   Kv= 5.0 fps
68.3
4,420
Total

Type III 24-hr  2 year Rainfall=3.20"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 12
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Subcatchment 3S: E-1
Runoff
Hydrograph
Time  (hours)
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Flow  (cfs)
50
45
40
35
30
25
20
15
10
5
0
Type III 24-hr
2 year Rainfall=3.20"
Runoff Area=101.737 ac
Runoff Volume=9.584 af
Runoff Depth>1.13"
Flow Length=4,420'
Tc=68.3 min
CN=76
47.88 cfs

Type III 24-hr  2 year Rainfall=3.20"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 13
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Summary for Reach 3R: Overland Flow
[79] Warning: Submerged Pond 6P Primary device # 1 OUTLET by 0.15'
Inflow Area =
13.736 ac, 38.54% Impervious,  Inflow Depth > 1.66"    for  2 year event
Inflow
=
2.93 cfs @ 13.38 hrs,  Volume=
1.902 af
Outflow
=
2.93 cfs @ 13.93 hrs,  Volume=
1.873 af,  Atten= 0%,  Lag= 32.8 min
Routing by Muskingum-Cunge method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs
Reference Flow= 2.20 cfs  Estimated Depth= 0.19'  Velocity= 0.23 fps
m= 1.662,  c= 0.39 fps,  dt= 0.6 min,  dx= 760.0' / 55 = 13.8',  K= 0.6 min,  X= 0.389
Max. Velocity= 0.42 fps,  Min. Travel Time= 30.3 min
Avg. Velocity = 0.34 fps,  Avg. Travel Time= 37.5 min
Peak Storage= 5,746 cf @ 13.70 hrs
Average Depth at Peak Storage= 0.15'
Bank-Full Depth= 1.00'  Flow Area= 51.0 sf,  Capacity= 35.52 cfs
50.00'  x  1.00'  deep channel,  n= 0.400
Side Slope Z-value= 1.0 '/'   Top Width= 52.00'
Length= 760.0'   Slope= 0.0368 '/'
Inlet Invert= 88.00',  Outlet Invert= 60.00'
‡

Type III 24-hr  2 year Rainfall=3.20"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 14
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Reach 3R: Overland Flow
Inflow
Outflow
Hydrograph
Time  (hours)
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Flow  (cfs)
3
2
1
0
Inflow Area=13.736 ac
Avg. Flow Depth=0.15'
Max Vel=0.42 fps
n=0.400
L=760.0'
S=0.0368 '/'
Capacity=35.52 cfs
2.93 cfs
2.93 cfs

Type III 24-hr  2 year Rainfall=3.20"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 15
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Summary for Pond 6P: Detention Basin
Inflow Area =
13.736 ac, 38.54% Impervious,  Inflow Depth > 1.83"    for  2 year event
Inflow
=
17.80 cfs @ 12.36 hrs,  Volume=
2.090 af
Outflow
=
2.93 cfs @ 13.38 hrs,  Volume=
1.902 af,  Atten= 84%,  Lag= 61.5 min
Primary
=
2.93 cfs @ 13.38 hrs,  Volume=
1.902 af
Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs
Peak Elev= 92.42' @ 13.38 hrs   Surf.Area= 20,256 sf   Storage= 44,281 cf
Plug-Flow detention time= 204.0 min calculated for 1.901 af (91% of inflow)
Center-of-Mass det. time= 160.6 min ( 998.5 - 837.8 )
Volume
Invert
Avail.Storage
Storage Description
#1
90.00'
127,579 cf
Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic-feet)
(cubic-feet)
90.00
16,410
0
0
92.00
19,568
35,978
35,978
94.00
22,870
42,438
78,416
95.00
24,576
23,723
102,139
96.00
26,304
25,440
127,579
Device
Routing     
Invert
Outlet Devices
#1
Primary
89.00'
24.0"  Round Culvert   
L= 112.0'   CPP, square edge headwall,  Ke= 0.500   
Inlet / Outlet Invert= 89.00' / 88.00'   S= 0.0089 '/'   Cc= 0.900   
n= 0.012,  Flow Area= 3.14 sf   
#2
Device 1
90.00'
10.0"  Round Culvert   
L= 5.0'   CPP, projecting, no headwall,  Ke= 0.900   
Inlet / Outlet Invert= 90.00' / 89.90'   S= 0.0200 '/'   Cc= 0.900   
n= 0.012,  Flow Area= 0.55 sf   
#3
Device 1
93.90'
30.0" Horiz. Orifice/Grate    C= 0.600   
Limited to weir flow at low heads   
#4
Primary
95.00'
20.0' long  x 13.0' 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)  2.60  2.64  2.70  2.66  2.65  2.66  2.65  2.63   
Primary OutFlow  Max=2.93 cfs @ 13.38 hrs  HW=92.42'   (Free Discharge)
1=Culvert  (Passes 2.93 cfs of 23.52 cfs potential flow)
2=Culvert  (Inlet Controls 2.93 cfs @ 5.38 fps)
3=Orifice/Grate  ( Controls 0.00 cfs)
4=Broad-Crested Rectangular Weir  ( Controls 0.00 cfs)

Type III 24-hr  2 year Rainfall=3.20"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 16
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Pond 6P: Detention Basin
Inflow
Primary
Hydrograph
Time  (hours)
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Flow  (cfs)
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Inflow Area=13.736 ac
Peak Elev=92.42'
Storage=44,281 cf
17.80 cfs
2.93 cfs

Type III 24-hr  2 year Rainfall=3.20"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 17
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Summary for Link 2L: Design Point
Inflow Area =
101.706 ac, 23.22% Impervious,  Inflow Depth > 1.15"    for  2 year event
Inflow
=
41.18 cfs @ 12.98 hrs,  Volume=
9.739 af
Primary
=
41.18 cfs @ 12.98 hrs,  Volume=
9.739 af,  Atten= 0%,  Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs
Link 2L: Design Point
Inflow
Primary
Hydrograph
Time  (hours)
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Flow  (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=101.706 ac
41.18 cfs
41.18 cfs

Type III 24-hr  5 year Rainfall=4.20"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 18
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Time span=0.00-24.00 hrs, dt=0.01 hrs, 2401 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Muskingum-Cunge method  -  Pond routing by Stor-Ind method
Runoff Area=87.970 ac   20.82% Impervious   Runoff Depth>1.79"
Subcatchment 1S: P-1
   Flow Length=4,420'   Tc=68.3 min   CN=75   Runoff=67.00 cfs  13.101 af
Runoff Area=13.736 ac   38.54% Impervious   Runoff Depth>2.71"
Subcatchment 2S: P-2
   Tc=26.0 min   CN=86   Runoff=26.38 cfs  3.108 af
Runoff Area=101.737 ac   20.18% Impervious   Runoff Depth>1.86"
Subcatchment 3S: E-1
   Flow Length=4,420'   Tc=68.3 min   CN=76   Runoff=81.00 cfs  15.781 af
Avg. Flow Depth=0.17'   Max Vel=0.45 fps   Inflow=3.69 cfs  2.800 af
Reach 3R: Overland Flow
n=0.400   L=760.0'   S=0.0368 '/'   Capacity=35.52 cfs   Outflow=3.69 cfs  2.746 af
Peak Elev=93.59'  Storage=69,188 cf   Inflow=26.38 cfs  3.108 af
Pond 6P: Detention Basin
   Outflow=3.69 cfs  2.800 af
   Inflow=70.03 cfs  15.846 af
Link 2L: Design Point
   Primary=70.03 cfs  15.846 af
Total Runoff Area = 203.443 ac   Runoff Volume = 31.990 af   Average Runoff Depth = 1.89"
78.30% Pervious = 159.296 ac     21.70% Impervious = 44.147 ac

Type III 24-hr  5 year Rainfall=4.20"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 19
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Summary for Subcatchment 1S: P-1
CarlsonPlanXYPos|1171180.9301|691042.4469|
CarlsonSurface||
Runoff
=
67.00 cfs @ 12.97 hrs,  Volume=
13.101 af,  Depth> 1.79"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs
Type III 24-hr  5 year Rainfall=4.20"
Area (ac)
CN
Description
11.076
98
Paved parking HSG A
10.583
79
Woods, Fair HSG D
1.449
76
Woods/grass comb., Fair HSG C
0.201
82
Woods/grass comb., Fair HSG D
3.504
36
Woods, Fair HSG A
16.559
73
Woods, Fair HSG C
3.932
60
Woods, Fair HSG B
0.822
98
Paved parking HSG B
0.523
98
Paved parking HSG D
5.898
98
Paved parking HSG C
10.774
49
50-75% Grass cover, Fair HSG A
3.488
69
50-75% Grass cover, Fair HSG B
18.163
79
50-75% Grass cover, Fair HSG C
0.998
84
50-75% Grass cover, Fair HSG D
87.970
75
Weighted Average
69.651
79.18% Pervious Area
18.319
20.82% Impervious Area
Tc
Length
Slope
Velocity
Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
14.3
100
0.0200
0.12
Sheet Flow, 
Grass: Dense   n= 0.240   P2= 3.20"
3.6
980
0.0490
4.49
Shallow Concentrated Flow, 
Paved   Kv= 20.3 fps
6.8
1,230
3.00
Direct Entry, pipe flow
43.6
2,110
0.0260
0.81
Shallow Concentrated Flow, 
Woodland   Kv= 5.0 fps
68.3
4,420
Total

Type III 24-hr  5 year Rainfall=4.20"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 20
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Subcatchment 1S: P-1
Runoff
Hydrograph
Time  (hours)
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Flow  (cfs)
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
0
Type III 24-hr
5 year Rainfall=4.20"
Runoff Area=87.970 ac
Runoff Volume=13.101 af
Runoff Depth>1.79"
Flow Length=4,420'
Tc=68.3 min
CN=75
67.00 cfs

Type III 24-hr  5 year Rainfall=4.20"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 21
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Summary for Subcatchment 2S: P-2
CarlsonPlanXYPos|1170813.5231|690121.8114|
CarlsonSurface||
Runoff
=
26.38 cfs @ 12.34 hrs,  Volume=
3.108 af,  Depth> 2.71"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs
Type III 24-hr  5 year Rainfall=4.20"
Area (ac)
CN
Description
0.464
73
Woods, Fair HSG C
0.525
76
Woods/grass comb., Fair HSG C
5.294
98
Paved parking HSG C
7.453
79
50-75% Grass cover, Fair HSG C
13.736
86
Weighted Average
8.442
61.46% Pervious Area
5.294
38.54% Impervious Area
Tc
Length
Slope
Velocity
Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
26.0
Direct Entry, Storm sewer TC
Subcatchment 2S: P-2
Runoff
Hydrograph
Time  (hours)
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Flow  (cfs)
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Type III 24-hr
5 year Rainfall=4.20"
Runoff Area=13.736 ac
Runoff Volume=3.108 af
Runoff Depth>2.71"
Tc=26.0 min
CN=86
26.38 cfs

Type III 24-hr  5 year Rainfall=4.20"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 22
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Summary for Subcatchment 3S: E-1
CarlsonPlanXYPos|1171180.9301|691042.4469|
CarlsonSurface||
Runoff
=
81.00 cfs @ 12.97 hrs,  Volume=
15.781 af,  Depth> 1.86"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs
Type III 24-hr  5 year Rainfall=4.20"
Area (ac)
CN
Description
11.076
98
Paved parking HSG A
10.583
79
Woods, Fair HSG D
1.982
76
Woods/grass comb., Fair HSG C
0.201
82
Woods/grass comb., Fair HSG D
3.504
36
Woods, Fair HSG A
24.566
73
Woods, Fair HSG C
3.932
60
Woods, Fair HSG B
0.822
98
Paved parking HSG B
0.523
98
Paved parking HSG D
8.113
98
Paved parking HSG C
10.775
49
50-75% Grass cover, Fair HSG A
3.488
69
50-75% Grass cover, Fair HSG B
21.174
79
50-75% Grass cover, Fair HSG C
0.998
84
50-75% Grass cover, Fair HSG D
101.737
76
Weighted Average
81.203
79.82% Pervious Area
20.534
20.18% Impervious Area
Tc
Length
Slope
Velocity
Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
14.3
100
0.0200
0.12
Sheet Flow, 
Grass: Dense   n= 0.240   P2= 3.20"
3.6
980
0.0490
4.49
Shallow Concentrated Flow, 
Paved   Kv= 20.3 fps
6.8
1,230
3.00
Direct Entry, pipe flow
43.6
2,110
0.0260
0.81
Shallow Concentrated Flow, watercourse
Woodland   Kv= 5.0 fps
68.3
4,420
Total

Type III 24-hr  5 year Rainfall=4.20"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 23
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Subcatchment 3S: E-1
Runoff
Hydrograph
Time  (hours)
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Flow  (cfs)
90
85
80
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
0
Type III 24-hr
5 year Rainfall=4.20"
Runoff Area=101.737 ac
Runoff Volume=15.781 af
Runoff Depth>1.86"
Flow Length=4,420'
Tc=68.3 min
CN=76
81.00 cfs

Type III 24-hr  5 year Rainfall=4.20"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 24
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Summary for Reach 3R: Overland Flow
[79] Warning: Submerged Pond 6P Primary device # 1 OUTLET by 0.17'
Inflow Area =
13.736 ac, 38.54% Impervious,  Inflow Depth > 2.45"    for  5 year event
Inflow
=
3.69 cfs @ 13.53 hrs,  Volume=
2.800 af
Outflow
=
3.69 cfs @ 14.03 hrs,  Volume=
2.746 af,  Atten= 0%,  Lag= 30.0 min
Routing by Muskingum-Cunge method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs
Reference Flow= 2.77 cfs  Estimated Depth= 0.22'  Velocity= 0.26 fps
m= 1.662,  c= 0.42 fps,  dt= 0.6 min,  dx= 760.0' / 50 = 15.2',  K= 0.6 min,  X= 0.384
Max. Velocity= 0.45 fps,  Min. Travel Time= 28.4 min
Avg. Velocity = 0.37 fps,  Avg. Travel Time= 34.1 min
Peak Storage= 6,612 cf @ 13.82 hrs
Average Depth at Peak Storage= 0.17'
Bank-Full Depth= 1.00'  Flow Area= 51.0 sf,  Capacity= 35.52 cfs
50.00'  x  1.00'  deep channel,  n= 0.400
Side Slope Z-value= 1.0 '/'   Top Width= 52.00'
Length= 760.0'   Slope= 0.0368 '/'
Inlet Invert= 88.00',  Outlet Invert= 60.00'
‡

Type III 24-hr  5 year Rainfall=4.20"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 25
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Reach 3R: Overland Flow
Inflow
Outflow
Hydrograph
Time  (hours)
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Flow  (cfs)
4
3
2
1
0
Inflow Area=13.736 ac
Avg. Flow Depth=0.17'
Max Vel=0.45 fps
n=0.400
L=760.0'
S=0.0368 '/'
Capacity=35.52 cfs
3.69 cfs
3.69 cfs

Type III 24-hr  5 year Rainfall=4.20"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 26
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Summary for Pond 6P: Detention Basin
Inflow Area =
13.736 ac, 38.54% Impervious,  Inflow Depth > 2.71"    for  5 year event
Inflow
=
26.38 cfs @ 12.34 hrs,  Volume=
3.108 af
Outflow
=
3.69 cfs @ 13.53 hrs,  Volume=
2.800 af,  Atten= 86%,  Lag= 71.4 min
Primary
=
3.69 cfs @ 13.53 hrs,  Volume=
2.800 af
Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs
Peak Elev= 93.59' @ 13.53 hrs   Surf.Area= 22,194 sf   Storage= 69,188 cf
Plug-Flow detention time= 237.3 min calculated for 2.799 af (90% of inflow)
Center-of-Mass det. time= 190.7 min ( 1,017.4 - 826.7 )
Volume
Invert
Avail.Storage
Storage Description
#1
90.00'
127,579 cf
Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic-feet)
(cubic-feet)
90.00
16,410
0
0
92.00
19,568
35,978
35,978
94.00
22,870
42,438
78,416
95.00
24,576
23,723
102,139
96.00
26,304
25,440
127,579
Device
Routing     
Invert
Outlet Devices
#1
Primary
89.00'
24.0"  Round Culvert   
L= 112.0'   CPP, square edge headwall,  Ke= 0.500   
Inlet / Outlet Invert= 89.00' / 88.00'   S= 0.0089 '/'   Cc= 0.900   
n= 0.012,  Flow Area= 3.14 sf   
#2
Device 1
90.00'
10.0"  Round Culvert   
L= 5.0'   CPP, projecting, no headwall,  Ke= 0.900   
Inlet / Outlet Invert= 90.00' / 89.90'   S= 0.0200 '/'   Cc= 0.900   
n= 0.012,  Flow Area= 0.55 sf   
#3
Device 1
93.90'
30.0" Horiz. Orifice/Grate    C= 0.600   
Limited to weir flow at low heads   
#4
Primary
95.00'
20.0' long  x 13.0' 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)  2.60  2.64  2.70  2.66  2.65  2.66  2.65  2.63   
Primary OutFlow  Max=3.69 cfs @ 13.53 hrs  HW=93.59'   (Free Discharge)
1=Culvert  (Passes 3.69 cfs of 28.66 cfs potential flow)
2=Culvert  (Inlet Controls 3.69 cfs @ 6.77 fps)
3=Orifice/Grate  ( Controls 0.00 cfs)
4=Broad-Crested Rectangular Weir  ( Controls 0.00 cfs)

Type III 24-hr  5 year Rainfall=4.20"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 27
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Pond 6P: Detention Basin
Inflow
Primary
Hydrograph
Time  (hours)
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Flow  (cfs)
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Inflow Area=13.736 ac
Peak Elev=93.59'
Storage=69,188 cf
26.38 cfs
3.69 cfs

Type III 24-hr  5 year Rainfall=4.20"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 28
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Summary for Link 2L: Design Point
Inflow Area =
101.706 ac, 23.22% Impervious,  Inflow Depth > 1.87"    for  5 year event
Inflow
=
70.03 cfs @ 12.98 hrs,  Volume=
15.846 af
Primary
=
70.03 cfs @ 12.98 hrs,  Volume=
15.846 af,  Atten= 0%,  Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs
Link 2L: Design Point
Inflow
Primary
Hydrograph
Time  (hours)
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Flow  (cfs)
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
0
Inflow Area=101.706 ac
70.03 cfs
70.03 cfs

Type III 24-hr  10 year Rainfall=4.80"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 29
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Time span=0.00-24.00 hrs, dt=0.01 hrs, 2401 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Muskingum-Cunge method  -  Pond routing by Stor-Ind method
Runoff Area=87.970 ac   20.82% Impervious   Runoff Depth>2.25"
Subcatchment 1S: P-1
   Flow Length=4,420'   Tc=68.3 min   CN=75   Runoff=85.03 cfs  16.501 af
Runoff Area=13.736 ac   38.54% Impervious   Runoff Depth>3.27"
Subcatchment 2S: P-2
   Tc=26.0 min   CN=86   Runoff=31.60 cfs  3.738 af
Runoff Area=101.737 ac   20.18% Impervious   Runoff Depth>2.33"
Subcatchment 3S: E-1
   Flow Length=4,420'   Tc=68.3 min   CN=76   Runoff=102.16 cfs  19.787 af
Avg. Flow Depth=0.24'   Max Vel=0.59 fps   Inflow=6.61 cfs  3.335 af
Reach 3R: Overland Flow
n=0.400   L=760.0'   S=0.0368 '/'   Capacity=35.52 cfs   Outflow=6.60 cfs  3.280 af
Peak Elev=94.12'  Storage=81,118 cf   Inflow=31.60 cfs  3.738 af
Pond 6P: Detention Basin
   Outflow=6.61 cfs  3.335 af
   Inflow=88.62 cfs  19.782 af
Link 2L: Design Point
   Primary=88.62 cfs  19.782 af
Total Runoff Area = 203.443 ac   Runoff Volume = 40.025 af   Average Runoff Depth = 2.36"
78.30% Pervious = 159.296 ac     21.70% Impervious = 44.147 ac

Type III 24-hr  10 year Rainfall=4.80"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 30
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Summary for Subcatchment 1S: P-1
CarlsonPlanXYPos|1171180.9301|691042.4469|
CarlsonSurface||
Runoff
=
85.03 cfs @ 12.97 hrs,  Volume=
16.501 af,  Depth> 2.25"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs
Type III 24-hr  10 year Rainfall=4.80"
Area (ac)
CN
Description
11.076
98
Paved parking HSG A
10.583
79
Woods, Fair HSG D
1.449
76
Woods/grass comb., Fair HSG C
0.201
82
Woods/grass comb., Fair HSG D
3.504
36
Woods, Fair HSG A
16.559
73
Woods, Fair HSG C
3.932
60
Woods, Fair HSG B
0.822
98
Paved parking HSG B
0.523
98
Paved parking HSG D
5.898
98
Paved parking HSG C
10.774
49
50-75% Grass cover, Fair HSG A
3.488
69
50-75% Grass cover, Fair HSG B
18.163
79
50-75% Grass cover, Fair HSG C
0.998
84
50-75% Grass cover, Fair HSG D
87.970
75
Weighted Average
69.651
79.18% Pervious Area
18.319
20.82% Impervious Area
Tc
Length
Slope
Velocity
Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
14.3
100
0.0200
0.12
Sheet Flow, 
Grass: Dense   n= 0.240   P2= 3.20"
3.6
980
0.0490
4.49
Shallow Concentrated Flow, 
Paved   Kv= 20.3 fps
6.8
1,230
3.00
Direct Entry, pipe flow
43.6
2,110
0.0260
0.81
Shallow Concentrated Flow, 
Woodland   Kv= 5.0 fps
68.3
4,420
Total

Type III 24-hr  10 year Rainfall=4.80"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 31
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Subcatchment 1S: P-1
Runoff
Hydrograph
Time  (hours)
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Flow  (cfs)
95
90
85
80
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
0
Type III 24-hr
10 year Rainfall=4.80"
Runoff Area=87.970 ac
Runoff Volume=16.501 af
Runoff Depth>2.25"
Flow Length=4,420'
Tc=68.3 min
CN=75
85.03 cfs

Type III 24-hr  10 year Rainfall=4.80"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 32
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Summary for Subcatchment 2S: P-2
CarlsonPlanXYPos|1170813.5231|690121.8114|
CarlsonSurface||
Runoff
=
31.60 cfs @ 12.34 hrs,  Volume=
3.738 af,  Depth> 3.27"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs
Type III 24-hr  10 year Rainfall=4.80"
Area (ac)
CN
Description
0.464
73
Woods, Fair HSG C
0.525
76
Woods/grass comb., Fair HSG C
5.294
98
Paved parking HSG C
7.453
79
50-75% Grass cover, Fair HSG C
13.736
86
Weighted Average
8.442
61.46% Pervious Area
5.294
38.54% Impervious Area
Tc
Length
Slope
Velocity
Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
26.0
Direct Entry, Storm sewer TC
Subcatchment 2S: P-2
Runoff
Hydrograph
Time  (hours)
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Flow  (cfs)
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Type III 24-hr
10 year Rainfall=4.80"
Runoff Area=13.736 ac
Runoff Volume=3.738 af
Runoff Depth>3.27"
Tc=26.0 min
CN=86
31.60 cfs

Type III 24-hr  10 year Rainfall=4.80"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 33
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Summary for Subcatchment 3S: E-1
CarlsonPlanXYPos|1171180.9301|691042.4469|
CarlsonSurface||
Runoff
=
102.16 cfs @ 12.97 hrs,  Volume=
19.787 af,  Depth> 2.33"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs
Type III 24-hr  10 year Rainfall=4.80"
Area (ac)
CN
Description
11.076
98
Paved parking HSG A
10.583
79
Woods, Fair HSG D
1.982
76
Woods/grass comb., Fair HSG C
0.201
82
Woods/grass comb., Fair HSG D
3.504
36
Woods, Fair HSG A
24.566
73
Woods, Fair HSG C
3.932
60
Woods, Fair HSG B
0.822
98
Paved parking HSG B
0.523
98
Paved parking HSG D
8.113
98
Paved parking HSG C
10.775
49
50-75% Grass cover, Fair HSG A
3.488
69
50-75% Grass cover, Fair HSG B
21.174
79
50-75% Grass cover, Fair HSG C
0.998
84
50-75% Grass cover, Fair HSG D
101.737
76
Weighted Average
81.203
79.82% Pervious Area
20.534
20.18% Impervious Area
Tc
Length
Slope
Velocity
Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
14.3
100
0.0200
0.12
Sheet Flow, 
Grass: Dense   n= 0.240   P2= 3.20"
3.6
980
0.0490
4.49
Shallow Concentrated Flow, 
Paved   Kv= 20.3 fps
6.8
1,230
3.00
Direct Entry, pipe flow
43.6
2,110
0.0260
0.81
Shallow Concentrated Flow, watercourse
Woodland   Kv= 5.0 fps
68.3
4,420
Total

Type III 24-hr  10 year Rainfall=4.80"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 34
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Subcatchment 3S: E-1
Runoff
Hydrograph
Time  (hours)
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Flow  (cfs)
110
105
100
95
90
85
80
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
0
Type III 24-hr
10 year Rainfall=4.80"
Runoff Area=101.737 ac
Runoff Volume=19.787 af
Runoff Depth>2.33"
Flow Length=4,420'
Tc=68.3 min
CN=76
102.16 cfs

Type III 24-hr  10 year Rainfall=4.80"
213009
  Printed  3/9/2022
Prepared by Provost & Rovero, Inc.
Page 35
HydroCAD® 10.00-13  s/n 02606  © 2014 HydroCAD Software Solutions LLC
Summary for Reach 3R: Overland Flow
[79] Warning: Submerged Pond 6P Primary device # 1