Conservation Commission Agenda (linked)

01 May 2025 
 
Gary Schneider 
Town of Waterford 
1000 Hartford Turnpike 
Waterford, CT 06385 
 
RE:
 
Stormwater Management Report 
Waterford Pickleball Courts and Parking 
Waterford, Connecticut 
Langan Project No.: 140310301 
 
Dear Mr. Schneider: 
 
This report provides an analysis of the proposed peak runoff discharges and the engineering 
design for the proposed stormwater management design for the proposed pickleball courts and 
parking at 51 Daniels Avenue. This report and design of the pickleball courts and parking has been 
prepared in conjunction with the LEARN Early Childhood School Project. As such, the “existing 
conditions” this report describes assumes the LEARN school building, site and stormwater 
improvements have been constructed. Refer to the report titled “Stormwater Management 
Report” for the LEARN Early Childhood School Project for additional information. 
PROJECT DESPCRIPTION 
Existing Conditions 
The project site is located at 51 Daniels Avenue in Waterford, CT; see Figure 1. The existing 
overall parcel is approximately 19.32 acres. LEARN is acquiring 15.36 acres of the existing parcel 
to be utilized for a proposed elementary school. The remaining 3.96 acres will be retained by the 
Town of Waterford. The pickleball courts will be located on the northeastern corner of this revised 
3.96 acre parcel. This portion of the site is currently occupied by existing grassy and wooded 
areas. The parcel is located within the Niantic River subregional drainage basin. The parcel area 
does not contain any known locations of State and Federal Listed Species and Critical Habitats 
per the CT Natural Diversity Data Base Areas map of Waterford, CT dated December 2024. To 
the north, the site is bordered by Daniels Avenue, to the east by wooded areas and residential 
properties, and to the south and west by the proposed LEARN school. All stormwater from this 
project site flows overland towards the off-site wetland pool to the west. No permanent site 
features will be located within the 100-ft upland review area and no direct impacts are proposed. 
 

Stormwater Management Report 
Waterford Pickleball Courts and Parking 
Waterford, Connecticut 
Langan Project No.: 140310301 
01 May 2025
Page 2 of 7 
 
 
 
According to the Federal Emergency Management Agency (FEMA) Flood Insurance Study of 
New London County, Connecticut map number 09011C0483J with an effective date of August 
5, 2013, the proposed development is located within Zone X (Unshaded). Zone X (Unshaded) is 
considered a Low-Risk Area and described by FEMA as areas outside the 0.2-percent-annual-
chance chance flood. No base flood elevations or base flood depths are shown within these 
zones; see Figure 2.  
According to the USDA Natural Resources Conservation Service Web Soil Survey, the site’s soil 
type varies throughout. The site is mostly classified as either Urban land with a D hydrologic 
rating and Charlton-Chatfield complex with a B hydrologic rating. 
Proposed Project 
The proposed project consists of the construction of two pickleball courts with parking and 
sidewalk access.  Additional improvements additional native plantings to provide an enhanced 
landscape buffer to the vernal pool. A summary of the change in impervious is shown below. 
Project Site Impervious Cover [SF] 
Existing Conditions
Proposed Conditions
Net Increase
±0
±4,750
±4,750
The site has been designed to maintain existing site hydrology to the maximum extent 
practicable.  Stormwater runoff from the pickleball courts and sidewalk will continue to sheet 
flow towards the enhanced landscaped area before eventually continuing to discharge to the 
existing wetland. These impervious areas will be inaccessible to vehicular traffic. 
See sheet titled “Site, grading, drainage, & sesc plan” for additional information. 
PEAK RUNOFF ANALYSIS (See Appendices A & B) 
The stormwater management system is designed to control the rate runoff from the site’s 
watersheds to be equal or less than existing conditions up to, and including, a 100-year design 
storm event. 
The peak runoff discharges for the existing and proposed conditions were analyzed using Soil 
Conservation Service (SCS) methodology which outlines procedures for calculating peak rates of 
runoff resulting from precipitation events as well as procedures for developing runoff 
hydrographs.  The entire site was included in the analysis; see Figures EXWS and PRWS.  Values 
for area, curve number (CN), and a time of concentration were calculated for the existing and 
proposed conditions.   

Stormwater Management Report 
Waterford Pickleball Courts and Parking 
Waterford, Connecticut 
Langan Project No.: 140310301 
01 May 2025
Page 3 of 7 
 
 
 
The curve number is a land sensitive coefficient that dictates the relationship between total 
rainfall depth and direct storm runoff.  The soils within the watershed are divided into hydrologic 
soil groups (A, B, C, and D).  The SCS classification system evaluates the runoff potential of a soil 
according to its infiltration and transmission rates.  “A” soils have the lowest runoff potential, 
while “D” soils have the greatest runoff potential.  Soils within the project area are predominantly 
“B” and “D” hydrologic rating. 
The time of concentration (Tc) is defined as the time for runoff to travel from the hydraulically 
most distant point in the watershed to a point of interest.  Values of time of concentration were 
determined for existing and proposed conditions based on land cover and slope of the flow path 
using methods outlined in TR-55. 
For this study, a 24-hour NOAA D rainfall distribution was used to determine the peak flow rate 
to all points of discharge from the site.  Precipitation data used for the various storm events is 
based on the “NOAA Atlas 14 Point Precipitation Frequency Estimates: CT” for the location as 
shown in Graphic 1. A summary of all rainfall data utilized in the analysis for this site is provided 
below and a complete compilation of data provided by NOAA for this location is included in 
Appendix C.  
Graphic 1. NOAA Rainfall Data Location Map 
 
 

Stormwater Management Report 
Waterford Pickleball Courts and Parking 
Waterford, Connecticut 
Langan Project No.: 140310301 
01 May 2025
Page 4 of 7 
 
 
 
NOAA Precipitation Depth per Average Recurrence Interval [in] 
Duration 
2-Year 
10-Year 
25-Year 
100-Year
24-hour 
3.44 
5.14 
6.21 
7.85
 
Existing Condition (See Appendix A) 
The project area’s existing drainage conditions were analyzed as a single watershed (See 
Drawing EXWS).  
Existing Watershed 1 is approximately 1.07 acres and consists mostly of grassy and wooded 
areas. Stormwater runoff from this watershed flows overland to the east and towards the off-
site wetland.  
Proposed Condition (See Appendix B) 
In the proposed condition, the site hydrology has been designed to match existing conditions to 
the maximum extent possible, and all watershed design points remain the same. 
Proposed Watershed 1 is about 1.05 acres and consists mostly of grassy and wooded areas. 
Stormwater from these areas will continue to flow overland to the east and towards the off-site 
wetland. 
On-site infiltration test was performed on April 16th, 2025, by Langan Engineering. Refer to 
Appendix D for test locations, results and test pit information.  
 
Site Discharge Peak Flow Comparison for WS-1 (CF) 
Storm 
Current
Proposed
Delta
% Reduction
2-Year 
1.27 
1.27 
- 
- 
10-Year 
2.69 
2.63 
-0.06 
-2% 
25-Year 
3.66 
3.55 
-0.11 
-3% 
100-Year
5.18 
5.00 
-0.13 
-3% 
 
As can be seen from the tables above, existing site hydrology has been maintained up to and 
including the 100-year storm.   
 
 

Stormwater Management Report 
Waterford Pickleball Courts and Parking 
Waterford, Connecticut 
Langan Project No.: 140310301 
01 May 2025
Page 5 of 7 
 
 
 
STORMWATER QUALITY 
All-Points Technology has identified an embedded vernal pool within the off-site wetland. The 
wetland assessment, see report titled “Wetland Assessment – Waterford Pickleball Courts and 
Parking” prepared by All-Points Technology, dated May 01, 2025, for additional information. 
Per the recommendations of the Wetland Assessment, no structural water quality improvements 
are proposed for this project based on two considerations.: (1) the proposed pickleball courts will 
not introduce any pollution sources such as vehicles, sand or salt and (2) the increased 
environmental benefits of maintaining the 100-foot upland review areas and venal pool envelope. 
This design prioritizes avoiding any disturbances within these areas, including the exclusion of 
stormwater structures, pipes, and detention systems. Instead, the project will implement LID 
improvements per Section 25.6.5.1 of the Town of Waterford Zoning Regulations. LID techniques 
such as directing flows to vegetated areas, encouraging sheet flow through vegetated areas, 
increasing vegetation, restricting ground disturbance, and maintain existing topography and 
drainage. 
Stormwater runoff from the proposed pickleball courts is not expected to contribute pollutant 
loads, as the area will not support vehicular traffic and as such, no structural stormwater 
treatment devices are necessary. Additionally, it was recommended to avoid any stormwater 
basin within close proximity to the venal pool due to the potential creation of a “decoy vernal 
pool”. This would pose a significant risk to unsuccessful vernal species breeding.  
CONCLUSION 
The proposed project has been designed to maintain existing drainage patterns to the greatest 
extent practicable. Stormwater runoff from the site has mimics existing hydrology with no 
increase in peak flow rates. This Langan report confirms that the proposed project, as designed, 
effectively manages the stormwater runoff for the proposed development. Please refer to the 
Drawings for additional drainage information. 
 
 
 
 
 
 
 
 
 
 
 
 

Stormwater Management Report 
Waterford Pickleball Courts and Parking 
Waterford, Connecticut 
Langan Project No.: 140310301 
01 May 2025
Page 6 of 7 
 
 
 
 
Sincerely, 
Langan Engineering and Environmental Services, LLC 
 
 
Bill Willsey, P.E. 
Senior Staff Engineer 
 
 
Kathryn Gagnon, P.E., LEED AP 
Senior Project Manager 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
\\langan.com\data\NHV\data3\140310301\Project Data\_Discipline\Site Civil\Reports\Stormwater - Pickleball\Pickleball - Stormwater Memo.docx 

Stormwater Management Report 
Waterford Pickleball Courts and Parking 
Waterford, Connecticut 
Langan Project No.: 140310301 
01 May 2025
Page 7 of 7 
 
 
 
LIST OF FIGURES 
 
Fig. 1  
 
Location Map 
 
Fig. 2  
 
FEMA Flood Map 
 
Fig. 3  
 
NRCS Soil Map 
 
LIST OF DRAWINGS 
 
EXWS  
 
Existing Watershed Map 
 
PRWS  
 
Proposed Watershed Map 
 
REFERENCE DRAWINGS 
 
CS101  
 
Site, Grading, Drainage, & SESC Plan 
 
LIST OF APPENDICES 
 
 
Appendix A  
Existing Stormwater Discharge Calculations 
Appendix B  
Proposed Stormwater Discharge Calculations 
Appendix C  
NOAA Rainfall Data 
Appendix D  
Test Pit & Infiltration Logs 
 

1

A
B
C
D
3
2
1
4
Project
© 2025 Langan
Project No.
Date
Scale
Drawn By
Submission Date
Figure
140310301
3/17/2025
Site Analyzer
3/17/2025
.
2
300 Kimball Drive 4th Floor
Parsippany NJ 07054-2172
T: 973-560-4900     F: 973-560-4901     www.langan.com
Langan Engineering & Environmental Services, LLC.
Langan Engineering, Environmental, Surveying, Landscape
 Architecture and Geology, D.P.C.
Langan International
Collectively known as Langan
1:12,000
0
500
1,000
ft
Sheet 2 of 2
EFFECTIVE FEMA
FIRM
Town of Waterford, MassGIS, UConn/CTDEEP, Esri, HERE, Garmin, INCREMENT P, USGS, METI/NASA, EPA, USDA,
State of Connecticut, Maxar; FEMA, FEMA RiskMap CDS
LEARN
Legend
Site Boundary
FIRM Panels
SFHA / Flood Zone Boundary
1% Annual Chance Flood
Hazard
1% Annual Chance Flood
Hazard
0.2% Annual Chance Flood
Hazard
Disclaimer: This information is produced by an automated system and may not be complete. The absence of a feature is not a confirmation that the feature is not present at the subject location. Information produced is in the public domain and unless noted has
not been field verified or provided for any specific use. Users are also cautioned to confirm the information shown is suitable for their intended use. Spatial Reference: NAD 1983 StatePlane Connecticut FIPS 0600 Feet. Projection: emptyStr=Lambert Conformal
Conic
WATERFORD
SOUTHEASTERN
CONNECTICUT
CT
Figure Title
2

3

Date: 4/28/2025  Time: 04:25  User: bwillsey  Style Table: Langan.stb  Layout: EXWS
Document Code: 140310301-0506-CG103-0101
www.langan.com
555 Long Wharf Drive, 9th Floor
New Haven, CT 06511
T: 203.562.5771F: 203.789.6142
Langan CT, Inc.
©
Langan
2024

Date: 4/30/2025  Time: 16:18  User: bwillsey  Style Table: Langan.stb  Layout: PRWS
Document Code: 140310301-0506-CG104-0101
www.langan.com
555 Long Wharf Drive, 9th Floor
New Haven, CT 06511
T: 203.562.5771F: 203.789.6142
Langan CT, Inc.
©
Langan
2024

SITE, GRADING,
DRAINAGE, & SESC
PLAN
CS101
05/01/2025
KEG
BTW
Date: 4/30/2025  Time: 14:17  User: bwillsey  Style Table: Langan.stb  Layout: CS101 Document Code: 140310301-0505-CS101-0101
As indicated
REVISIONS
NO
 DATE
 DESCRIPTION
SCALE:
NOT FOR
CONSTRUCTION
2
CLIENT
ARCHITECTURAL CONSULTANT & LANDSCAPE
N
CIVIL & GEOTECH ENGINEER
STRUCTURAL ENGINEER
MEPFP ENGINEER
1
3
4
5
6
7
E
D
C
B
A
DRAWING TITLE:
CHECKED BY:
DATE:
DRAWN BY:
DRAWING NUMBER:
NEWMAN PROJECT NUMBER:
PROJECT ADDRESS:
PROJECT NAME:
PHASE:
E
D
C
B
2
1
3
4
5
6
A
7
NEWMAN ARCHITECTS, PC
THE DRAWINGS, DESIGNS, PLANS, SPECIFICATIONS, AND
ALL WORKS AND CONTENT DISPLAYED, CONTAINED, OR
REPRESENTED HEREIN ARE THE SOLE AND EXCLUSIVE
PROPERTY OF NEWMAN ARCHITECTS, P.C. COPYRIGHT ©
           NEWMAN ARCHITECTS P.C. ALL RIGHTS
RESERVED.
265 Church Street, 15th Floor
New Haven, CT 06510
203.772.1990 Fax 203.772.1997
www.newmanarchitects.com
STATE PROJECT NUMBER:
245-0090 MAG/A/PF
ACOUSTICAL ENGINEER
JAFFE HOLDEN
114A WASHINGTON ST, SUITE 2
NORWALK, CT 06854
(203) 838-4167
TECH FF&E
D'AGOSTINO & ASSOCIATES
477 MAIN ST
MONROE, CT 06468
(203) 497-3064
SUSTAINABILITY CONSULTANT
THE GREEN ENGINEER
23 BRADFORD
CONCORD, MA 01742
(978) 369-8978
RDG PLANNING & DESIGN
1302 HOWARD STREET
OMAHA, NE 68102
T 402.392.0133
LANGAN ENGINEERING & ENVIRONMENTAL
SERVICES
555 LONG WHARF DRIVE, 9TH FLOOR
NEW HAVEN, CT 06511
(203) 562-5771
E2 ENGINEERS
488 MONTAUK AVE.
NEW LONDON, CT 06320
860-437-3259
CES
811 MIDDLE STREET
MIDDLETOWN, CT 06457
860-632-1682
LEARN
44 HATCHETTS HILL ROAD
OLD LYME, CT 06371
860-434-4800
WATERFORD CONSERVATION
SUBMISSION
20240069
51 DANIELS AVE,
WATERFORD, CT 06385
WATERFORD
PICKLEBALL COURTS
AND PARKING
STATE PROJECT NUMBER:
245-0090 MAG/N/PF

 
 
APPENDIX A 
Existing Stormwater Discharge Calculations 
 
 

EXWS-1
Routing Diagram for EX WS_Pickleball
Prepared by Langan Engineering,  Printed 4/28/2025
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Subcat
Reach
Pond
Link

EX WS_Pickleball
  Printed  4/28/2025
Prepared by Langan Engineering
Page 2
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Area Listing (all nodes)
Area
(acres)
CN
Description
(subcatchment-numbers)
0.37
84
50-75% Grass cover, Fair, HSG D  (EXWS-1)
0.02
78
Meadow, HSG D  (EXWS-1)
0.25
55
Woods, Good, HSG B  (EXWS-1)
0.42
77
Woods, Good, HSG D  (EXWS-1)
1.07
74
TOTAL AREA

NOAA 24-hr D  2-Year Rainfall=3.44"
EX WS_Pickleball
  Printed  4/28/2025
Prepared by Langan Engineering
Page 3
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Time span=0.00-48.00 hrs, dt=0.02 hrs, 2401 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method  -  Pond routing by Stor-Ind method
Runoff Area=1.07 ac   0.00% Impervious   Runoff Depth=1.20"
Subcatchment EXWS-1: 
   Flow Length=284'   Tc=10 min   CN=74   Runoff=1.27 cfs  4,660 CF
Total Runoff Area = 1.07 ac   Runoff Volume = 4,660 CF   Average Runoff Depth = 1.20"
100.00% Pervious = 1.07 ac     0.00% Impervious = 0.00 ac

NOAA 24-hr D  2-Year Rainfall=3.44"
EX WS_Pickleball
  Printed  4/28/2025
Prepared by Langan Engineering
Page 4
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Summary for Subcatchment EXWS-1: 
Runoff
=
1.27 cfs @ 12.18 hrs,  Volume=
4,660 CF,  Depth= 1.20"
     Routed to nonexistent node Site
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.02 hrs
NOAA 24-hr D  2-Year Rainfall=3.44"
Area (ac)
CN
Description
*
0.00
98
Impervious
0.00
69
50-75% Grass cover, Fair, HSG B
0.00
79
50-75% Grass cover, Fair, HSG C
0.37
84
50-75% Grass cover, Fair, HSG D
*
0.02
78
Meadow, HSG D
0.25
55
Woods, Good, HSG B
0.00
70
Woods, Good, HSG C
0.42
77
Woods, Good, HSG D
1.07
74
Weighted Average
1.07
100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
8
150
0.0650
0.31
Sheet Flow, AB
Grass: Short   n= 0.150   P2= 3.44"
0
50
0.0650
1.78
Shallow Concentrated Flow, BC
Short Grass Pasture   Kv= 7.0 fps
1
84
0.0550
1.17
Shallow Concentrated Flow, CD
Woodland   Kv= 5.0 fps
10
284
Total

NOAA 24-hr D  2-Year Rainfall=3.44"
EX WS_Pickleball
  Printed  4/28/2025
Prepared by Langan Engineering
Page 5
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Subcatchment EXWS-1: 
Runoff
Hydrograph
Time  (hours)
48
46
44
42
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Flow  (cfs)
1
0
NOAA 24-hr D
2-Year Rainfall=3.44"
Runoff Area=1.07 ac
Runoff Volume=4,660 CF
Runoff Depth=1.20"
Flow Length=284'
Tc=10 min
CN=74
1.27 cfs

NOAA 24-hr D  10-Year Rainfall=5.14"
EX WS_Pickleball
  Printed  4/28/2025
Prepared by Langan Engineering
Page 6
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Time span=0.00-48.00 hrs, dt=0.02 hrs, 2401 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method  -  Pond routing by Stor-Ind method
Runoff Area=1.07 ac   0.00% Impervious   Runoff Depth=2.48"
Subcatchment EXWS-1: 
   Flow Length=284'   Tc=10 min   CN=74   Runoff=2.69 cfs  9,628 CF
Total Runoff Area = 1.07 ac   Runoff Volume = 9,628 CF   Average Runoff Depth = 2.48"
100.00% Pervious = 1.07 ac     0.00% Impervious = 0.00 ac

NOAA 24-hr D  10-Year Rainfall=5.14"
EX WS_Pickleball
  Printed  4/28/2025
Prepared by Langan Engineering
Page 7
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Summary for Subcatchment EXWS-1: 
Runoff
=
2.69 cfs @ 12.17 hrs,  Volume=
9,628 CF,  Depth= 2.48"
     Routed to nonexistent node Site
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.02 hrs
NOAA 24-hr D  10-Year Rainfall=5.14"
Area (ac)
CN
Description
*
0.00
98
Impervious
0.00
69
50-75% Grass cover, Fair, HSG B
0.00
79
50-75% Grass cover, Fair, HSG C
0.37
84
50-75% Grass cover, Fair, HSG D
*
0.02
78
Meadow, HSG D
0.25
55
Woods, Good, HSG B
0.00
70
Woods, Good, HSG C
0.42
77
Woods, Good, HSG D
1.07
74
Weighted Average
1.07
100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
8
150
0.0650
0.31
Sheet Flow, AB
Grass: Short   n= 0.150   P2= 3.44"
0
50
0.0650
1.78
Shallow Concentrated Flow, BC
Short Grass Pasture   Kv= 7.0 fps
1
84
0.0550
1.17
Shallow Concentrated Flow, CD
Woodland   Kv= 5.0 fps
10
284
Total

NOAA 24-hr D  10-Year Rainfall=5.14"
EX WS_Pickleball
  Printed  4/28/2025
Prepared by Langan Engineering
Page 8
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Subcatchment EXWS-1: 
Runoff
Hydrograph
Time  (hours)
48
46
44
42
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Flow  (cfs)
3
2
1
0
NOAA 24-hr D
10-Year Rainfall=5.14"
Runoff Area=1.07 ac
Runoff Volume=9,628 CF
Runoff Depth=2.48"
Flow Length=284'
Tc=10 min
CN=74
2.69 cfs

NOAA 24-hr D  25-Year Rainfall=6.21"
EX WS_Pickleball
  Printed  4/28/2025
Prepared by Langan Engineering
Page 9
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Time span=0.00-48.00 hrs, dt=0.02 hrs, 2401 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method  -  Pond routing by Stor-Ind method
Runoff Area=1.07 ac   0.00% Impervious   Runoff Depth=3.36"
Subcatchment EXWS-1: 
   Flow Length=284'   Tc=10 min   CN=74   Runoff=3.66 cfs  13,072 CF
Total Runoff Area = 1.07 ac   Runoff Volume = 13,072 CF   Average Runoff Depth = 3.36"
100.00% Pervious = 1.07 ac     0.00% Impervious = 0.00 ac

NOAA 24-hr D  25-Year Rainfall=6.21"
EX WS_Pickleball
  Printed  4/28/2025
Prepared by Langan Engineering
Page 10
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Summary for Subcatchment EXWS-1: 
Runoff
=
3.66 cfs @ 12.17 hrs,  Volume=
13,072 CF,  Depth= 3.36"
     Routed to nonexistent node Site
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.02 hrs
NOAA 24-hr D  25-Year Rainfall=6.21"
Area (ac)
CN
Description
*
0.00
98
Impervious
0.00
69
50-75% Grass cover, Fair, HSG B
0.00
79
50-75% Grass cover, Fair, HSG C
0.37
84
50-75% Grass cover, Fair, HSG D
*
0.02
78
Meadow, HSG D
0.25
55
Woods, Good, HSG B
0.00
70
Woods, Good, HSG C
0.42
77
Woods, Good, HSG D
1.07
74
Weighted Average
1.07
100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
8
150
0.0650
0.31
Sheet Flow, AB
Grass: Short   n= 0.150   P2= 3.44"
0
50
0.0650
1.78
Shallow Concentrated Flow, BC
Short Grass Pasture   Kv= 7.0 fps
1
84
0.0550
1.17
Shallow Concentrated Flow, CD
Woodland   Kv= 5.0 fps
10
284
Total

NOAA 24-hr D  25-Year Rainfall=6.21"
EX WS_Pickleball
  Printed  4/28/2025
Prepared by Langan Engineering
Page 11
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Subcatchment EXWS-1: 
Runoff
Hydrograph
Time  (hours)
48
46
44
42
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Flow  (cfs)
4
3
2
1
0
NOAA 24-hr D
25-Year Rainfall=6.21"
Runoff Area=1.07 ac
Runoff Volume=13,072 CF
Runoff Depth=3.36"
Flow Length=284'
Tc=10 min
CN=74
3.66 cfs

NOAA 24-hr D  100-Year Rainfall=7.85"
EX WS_Pickleball
  Printed  4/28/2025
Prepared by Langan Engineering
Page 12
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Time span=0.00-48.00 hrs, dt=0.02 hrs, 2401 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method  -  Pond routing by Stor-Ind method
Runoff Area=1.07 ac   0.00% Impervious   Runoff Depth=4.79"
Subcatchment EXWS-1: 
   Flow Length=284'   Tc=10 min   CN=74   Runoff=5.18 cfs  18,629 CF
Total Runoff Area = 1.07 ac   Runoff Volume = 18,629 CF   Average Runoff Depth = 4.79"
100.00% Pervious = 1.07 ac     0.00% Impervious = 0.00 ac

NOAA 24-hr D  100-Year Rainfall=7.85"
EX WS_Pickleball
  Printed  4/28/2025
Prepared by Langan Engineering
Page 13
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Summary for Subcatchment EXWS-1: 
Runoff
=
5.18 cfs @ 12.17 hrs,  Volume=
18,629 CF,  Depth= 4.79"
     Routed to nonexistent node Site
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.02 hrs
NOAA 24-hr D  100-Year Rainfall=7.85"
Area (ac)
CN
Description
*
0.00
98
Impervious
0.00
69
50-75% Grass cover, Fair, HSG B
0.00
79
50-75% Grass cover, Fair, HSG C
0.37
84
50-75% Grass cover, Fair, HSG D
*
0.02
78
Meadow, HSG D
0.25
55
Woods, Good, HSG B
0.00
70
Woods, Good, HSG C
0.42
77
Woods, Good, HSG D
1.07
74
Weighted Average
1.07
100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
8
150
0.0650
0.31
Sheet Flow, AB
Grass: Short   n= 0.150   P2= 3.44"
0
50
0.0650
1.78
Shallow Concentrated Flow, BC
Short Grass Pasture   Kv= 7.0 fps
1
84
0.0550
1.17
Shallow Concentrated Flow, CD
Woodland   Kv= 5.0 fps
10
284
Total

NOAA 24-hr D  100-Year Rainfall=7.85"
EX WS_Pickleball
  Printed  4/28/2025
Prepared by Langan Engineering
Page 14
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Subcatchment EXWS-1: 
Runoff
Hydrograph
Time  (hours)
48
46
44
42
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Flow  (cfs)
5
4
3
2
1
0
NOAA 24-hr D
100-Year Rainfall=7.85"
Runoff Area=1.07 ac
Runoff Volume=18,629 CF
Runoff Depth=4.79"
Flow Length=284'
Tc=10 min
CN=74
5.18 cfs

 
 
 
APPENDIX B 
Proposed Stormwater Discharge Calculations 
 
 
 

PRWS-1
Routing Diagram for PR WS_Pickleball
Prepared by Langan Engineering,  Printed 4/30/2025
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Subcat
Reach
Pond
Link

PR WS_Pickleball
  Printed  4/30/2025
Prepared by Langan Engineering
Page 2
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Area Listing (all nodes)
Area
(acres)
CN
Description
(subcatchment-numbers)
0.06
84
50-75% Grass cover, Fair, HSG D  (PRWS-1)
0.11
98
Impervious  (PRWS-1)
0.29
78
Meadow, HSG D  (PRWS-1)
0.25
55
Woods, Good, HSG B  (PRWS-1)
0.35
77
Woods, Good, HSG D  (PRWS-1)
1.05
75
TOTAL AREA

NOAA 24-hr D  2-Year Rainfall=3.44"
PR WS_Pickleball
  Printed  4/30/2025
Prepared by Langan Engineering
Page 3
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Time span=0.00-48.00 hrs, dt=0.02 hrs, 2401 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method  -  Pond routing by Stor-Ind method
Runoff Area=45,869 sf   10.35% Impervious   Runoff Depth=1.26"
Subcatchment PRWS-1: 
   Flow Length=94'   Tc=11 min   CN=75   Runoff=1.27 cfs  4,814 CF
Total Runoff Area = 1.05 ac   Runoff Volume = 4,814 CF   Average Runoff Depth = 1.26"
89.65% Pervious = 0.94 ac     10.35% Impervious = 0.11 ac

NOAA 24-hr D  2-Year Rainfall=3.44"
PR WS_Pickleball
  Printed  4/30/2025
Prepared by Langan Engineering
Page 4
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Summary for Subcatchment PRWS-1: 
Runoff
=
1.27 cfs @ 12.19 hrs,  Volume=
4,814 CF,  Depth= 1.26"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.02 hrs
NOAA 24-hr D  2-Year Rainfall=3.44"
Area (sf)
CN
Description
*
4,748
98
Impervious
0
69
50-75% Grass cover, Fair, HSG B
0
79
50-75% Grass cover, Fair, HSG C
2,400
84
50-75% Grass cover, Fair, HSG D
0
80
>75% Grass cover, Good, HSG D
10,977
55
Woods, Good, HSG B
0
70
Woods, Good, HSG C
15,035
77
Woods, Good, HSG D
*
12,709
78
Meadow, HSG D
45,869
75
Weighted Average
41,121
89.65% Pervious Area
4,748
10.35% Impervious Area
Tc
Length
Slope
Velocity
Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
4
32
0.0450
0.13
Sheet Flow, AB
Grass: Dense   n= 0.240   P2= 3.44"
7
62
0.1200
0.15
Sheet Flow, AB
Woods: Light underbrush   n= 0.400   P2= 3.44"
11
94
Total

NOAA 24-hr D  2-Year Rainfall=3.44"
PR WS_Pickleball
  Printed  4/30/2025
Prepared by Langan Engineering
Page 5
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Subcatchment PRWS-1: 
Runoff
Hydrograph
Time  (hours)
48
46
44
42
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Flow  (cfs)
1
0
NOAA 24-hr D
2-Year Rainfall=3.44"
Runoff Area=45,869 sf
Runoff Volume=4,814 CF
Runoff Depth=1.26"
Flow Length=94'
Tc=11 min
CN=75
1.27 cfs

NOAA 24-hr D  10-Year Rainfall=5.14"
PR WS_Pickleball
  Printed  4/30/2025
Prepared by Langan Engineering
Page 6
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Time span=0.00-48.00 hrs, dt=0.02 hrs, 2401 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method  -  Pond routing by Stor-Ind method
Runoff Area=45,869 sf   10.35% Impervious   Runoff Depth=2.56"
Subcatchment PRWS-1: 
   Flow Length=94'   Tc=11 min   CN=75   Runoff=2.63 cfs  9,798 CF
Total Runoff Area = 1.05 ac   Runoff Volume = 9,798 CF   Average Runoff Depth = 2.56"
89.65% Pervious = 0.94 ac     10.35% Impervious = 0.11 ac

NOAA 24-hr D  10-Year Rainfall=5.14"
PR WS_Pickleball
  Printed  4/30/2025
Prepared by Langan Engineering
Page 7
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Summary for Subcatchment PRWS-1: 
Runoff
=
2.63 cfs @ 12.19 hrs,  Volume=
9,798 CF,  Depth= 2.56"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.02 hrs
NOAA 24-hr D  10-Year Rainfall=5.14"
Area (sf)
CN
Description
*
4,748
98
Impervious
0
69
50-75% Grass cover, Fair, HSG B
0
79
50-75% Grass cover, Fair, HSG C
2,400
84
50-75% Grass cover, Fair, HSG D
0
80
>75% Grass cover, Good, HSG D
10,977
55
Woods, Good, HSG B
0
70
Woods, Good, HSG C
15,035
77
Woods, Good, HSG D
*
12,709
78
Meadow, HSG D
45,869
75
Weighted Average
41,121
89.65% Pervious Area
4,748
10.35% Impervious Area
Tc
Length
Slope
Velocity
Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
4
32
0.0450
0.13
Sheet Flow, AB
Grass: Dense   n= 0.240   P2= 3.44"
7
62
0.1200
0.15
Sheet Flow, AB
Woods: Light underbrush   n= 0.400   P2= 3.44"
11
94
Total

NOAA 24-hr D  10-Year Rainfall=5.14"
PR WS_Pickleball
  Printed  4/30/2025
Prepared by Langan Engineering
Page 8
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Subcatchment PRWS-1: 
Runoff
Hydrograph
Time  (hours)
48
46
44
42
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Flow  (cfs)
2
1
0
NOAA 24-hr D
10-Year Rainfall=5.14"
Runoff Area=45,869 sf
Runoff Volume=9,798 CF
Runoff Depth=2.56"
Flow Length=94'
Tc=11 min
CN=75
2.63 cfs

NOAA 24-hr D  25-Year Rainfall=6.21"
PR WS_Pickleball
  Printed  4/30/2025
Prepared by Langan Engineering
Page 9
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Time span=0.00-48.00 hrs, dt=0.02 hrs, 2401 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method  -  Pond routing by Stor-Ind method
Runoff Area=45,869 sf   10.35% Impervious   Runoff Depth=3.46"
Subcatchment PRWS-1: 
   Flow Length=94'   Tc=11 min   CN=75   Runoff=3.55 cfs  13,232 CF
Total Runoff Area = 1.05 ac   Runoff Volume = 13,232 CF   Average Runoff Depth = 3.46"
89.65% Pervious = 0.94 ac     10.35% Impervious = 0.11 ac

NOAA 24-hr D  25-Year Rainfall=6.21"
PR WS_Pickleball
  Printed  4/30/2025
Prepared by Langan Engineering
Page 10
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Summary for Subcatchment PRWS-1: 
Runoff
=
3.55 cfs @ 12.18 hrs,  Volume=
13,232 CF,  Depth= 3.46"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.02 hrs
NOAA 24-hr D  25-Year Rainfall=6.21"
Area (sf)
CN
Description
*
4,748
98
Impervious
0
69
50-75% Grass cover, Fair, HSG B
0
79
50-75% Grass cover, Fair, HSG C
2,400
84
50-75% Grass cover, Fair, HSG D
0
80
>75% Grass cover, Good, HSG D
10,977
55
Woods, Good, HSG B
0
70
Woods, Good, HSG C
15,035
77
Woods, Good, HSG D
*
12,709
78
Meadow, HSG D
45,869
75
Weighted Average
41,121
89.65% Pervious Area
4,748
10.35% Impervious Area
Tc
Length
Slope
Velocity
Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
4
32
0.0450
0.13
Sheet Flow, AB
Grass: Dense   n= 0.240   P2= 3.44"
7
62
0.1200
0.15
Sheet Flow, AB
Woods: Light underbrush   n= 0.400   P2= 3.44"
11
94
Total

NOAA 24-hr D  25-Year Rainfall=6.21"
PR WS_Pickleball
  Printed  4/30/2025
Prepared by Langan Engineering
Page 11
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Subcatchment PRWS-1: 
Runoff
Hydrograph
Time  (hours)
48
46
44
42
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Flow  (cfs)
3
2
1
0
NOAA 24-hr D
25-Year Rainfall=6.21"
Runoff Area=45,869 sf
Runoff Volume=13,232 CF
Runoff Depth=3.46"
Flow Length=94'
Tc=11 min
CN=75
3.55 cfs

NOAA 24-hr D  100-Year Rainfall=7.85"
PR WS_Pickleball
  Printed  4/30/2025
Prepared by Langan Engineering
Page 12
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Time span=0.00-48.00 hrs, dt=0.02 hrs, 2401 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method  -  Pond routing by Stor-Ind method
Runoff Area=45,869 sf   10.35% Impervious   Runoff Depth=4.91"
Subcatchment PRWS-1: 
   Flow Length=94'   Tc=11 min   CN=75   Runoff=5.00 cfs  18,755 CF
Total Runoff Area = 1.05 ac   Runoff Volume = 18,755 CF   Average Runoff Depth = 4.91"
89.65% Pervious = 0.94 ac     10.35% Impervious = 0.11 ac

NOAA 24-hr D  100-Year Rainfall=7.85"
PR WS_Pickleball
  Printed  4/30/2025
Prepared by Langan Engineering
Page 13
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Summary for Subcatchment PRWS-1: 
Runoff
=
5.00 cfs @ 12.18 hrs,  Volume=
18,755 CF,  Depth= 4.91"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.02 hrs
NOAA 24-hr D  100-Year Rainfall=7.85"
Area (sf)
CN
Description
*
4,748
98
Impervious
0
69
50-75% Grass cover, Fair, HSG B
0
79
50-75% Grass cover, Fair, HSG C
2,400
84
50-75% Grass cover, Fair, HSG D
0
80
>75% Grass cover, Good, HSG D
10,977
55
Woods, Good, HSG B
0
70
Woods, Good, HSG C
15,035
77
Woods, Good, HSG D
*
12,709
78
Meadow, HSG D
45,869
75
Weighted Average
41,121
89.65% Pervious Area
4,748
10.35% Impervious Area
Tc
Length
Slope
Velocity
Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
4
32
0.0450
0.13
Sheet Flow, AB
Grass: Dense   n= 0.240   P2= 3.44"
7
62
0.1200
0.15
Sheet Flow, AB
Woods: Light underbrush   n= 0.400   P2= 3.44"
11
94
Total

NOAA 24-hr D  100-Year Rainfall=7.85"
PR WS_Pickleball
  Printed  4/30/2025
Prepared by Langan Engineering
Page 14
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Subcatchment PRWS-1: 
Runoff
Hydrograph
Time  (hours)
48
46
44
42
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Flow  (cfs)
5
4
3
2
1
0
NOAA 24-hr D
100-Year Rainfall=7.85"
Runoff Area=45,869 sf
Runoff Volume=18,755 CF
Runoff Depth=4.91"
Flow Length=94'
Tc=11 min
CN=75
5.00 cfs

 
 
APPENDIX C 
NOAA Rainfall Data 
 
 

NOAA Atlas 14, Volume 10, Version 3
Location name: Town of Waterford, Connecticut,
USA*
Latitude: 41.3325°, Longitude: -72.1669°
Elevation: 116 ft**
* source: ESRI Maps
** source: USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
Sanja Perica, Sandra Pavlovic, Michael St. Laurent, Carl Trypaluk, Dale Unruh, Orlan Wilhite
NOAA, National Weather Service, Silver Spring, Maryland
PF_tabular | PF_graphical | Maps_&_aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1
Duration
Average recurrence interval (years)
1
2
5
10
25
50
100
200
500
1000
5-min
0.336
(0.259‑0.427)
0.402
(0.310‑0.511)
0.510
(0.392‑0.651)
0.600
(0.458‑0.768)
0.723
(0.537‑0.960)
0.816
(0.594‑1.10)
0.914
(0.648‑1.27)
1.03
(0.689‑1.44)
1.19
(0.770‑1.72)
1.33
(0.840‑1.95)
10-min
0.475
(0.367‑0.605)
0.569
(0.438‑0.725)
0.723
(0.555‑0.921)
0.850
(0.649‑1.09)
1.02
(0.760‑1.36)
1.16
(0.841‑1.56)
1.30
(0.918‑1.80)
1.45
(0.977‑2.05)
1.69
(1.09‑2.44)
1.88
(1.19‑2.76)
15-min
0.559
(0.431‑0.711)
0.670
(0.516‑0.852)
0.851
(0.654‑1.09)
1.00
(0.764‑1.28)
1.21
(0.894‑1.60)
1.36
(0.989‑1.84)
1.52
(1.08‑2.12)
1.71
(1.15‑2.40)
1.98
(1.28‑2.86)
2.21
(1.40‑3.24)
30-min
0.791
(0.610‑1.01)
0.946
(0.729‑1.20)
1.20
(0.922‑1.53)
1.41
(1.08‑1.81)
1.70
(1.26‑2.26)
1.92
(1.40‑2.59)
2.15
(1.52‑2.99)
2.41
(1.62‑3.39)
2.79
(1.81‑4.03)
3.11
(1.97‑4.56)
60-min
1.02
(0.789‑1.30)
1.22
(0.942‑1.56)
1.55
(1.19‑1.98)
1.82
(1.39‑2.33)
2.20
(1.63‑2.91)
2.48
(1.80‑3.34)
2.77
(1.96‑3.85)
3.11
(2.09‑4.37)
3.60
(2.33‑5.20)
4.01
(2.54‑5.88)
2-hr
1.34
(1.04‑1.69)
1.60
(1.25‑2.02)
2.04
(1.58‑2.58)
2.39
(1.85‑3.04)
2.89
(2.16‑3.80)
3.26
(2.39‑4.36)
3.65
(2.61‑5.03)
4.10
(2.77‑5.71)
4.76
(3.10‑6.82)
5.32
(3.38‑7.73)
3-hr
1.56
(1.22‑1.95)
1.86
(1.46‑2.34)
2.36
(1.84‑2.97)
2.78
(2.15‑3.51)
3.35
(2.52‑4.38)
3.77
(2.78‑5.02)
4.23
(3.04‑5.80)
4.76
(3.22‑6.59)
5.53
(3.61‑7.87)
6.19
(3.94‑8.93)
6-hr
1.98
(1.56‑2.46)
2.36
(1.87‑2.94)
2.99
(2.36‑3.73)
3.51
(2.75‑4.40)
4.23
(3.21‑5.48)
4.77
(3.55‑6.28)
5.34
(3.86‑7.26)
6.00
(4.09‑8.23)
6.98
(4.58‑9.83)
7.80
(5.00‑11.1)
12-hr
2.45
(1.96‑3.02)
2.92
(2.33‑3.60)
3.69
(2.94‑4.56)
4.33
(3.42‑5.37)
5.21
(3.99‑6.69)
5.87
(4.40‑7.66)
6.57
(4.79‑8.84)
7.38
(5.06‑10.0)
8.57
(5.65‑12.0)
9.57
(6.16‑13.5)
24-hr
2.87
(2.32‑3.50)
3.44
(2.77‑4.19)
4.37
(3.51‑5.34)
5.14
(4.11‑6.31)
6.21
(4.80‑7.90)
7.00
(5.30‑9.06)
7.85
(5.78‑10.5)
8.85
(6.11‑11.9)
10.3
(6.85‑14.3)
11.6
(7.50‑16.2)
2-day
3.20
(2.61‑3.86)
3.87
(3.16‑4.68)
4.98
(4.04‑6.03)
5.89
(4.76‑7.17)
7.16
(5.59‑9.04)
8.09
(6.19‑10.4)
9.10
(6.77‑12.1)
10.3
(7.17‑13.8)
12.2
(8.13‑16.7)
13.8
(8.97‑19.1)
3-day
3.46
(2.84‑4.15)
4.18
(3.43‑5.03)
5.37
(4.39‑6.47)
6.36
(5.16‑7.68)
7.71
(6.06‑9.69)
8.72
(6.70‑11.1)
9.80
(7.33‑13.0)
11.1
(7.76‑14.7)
13.1
(8.78‑17.9)
14.9
(9.69‑20.5)
4-day
3.71
(3.06‑4.43)
4.47
(3.68‑5.34)
5.70
(4.68‑6.84)
6.73
(5.49‑8.11)
8.15
(6.42‑10.2)
9.19
(7.10‑11.7)
10.3
(7.74‑13.6)
11.7
(8.18‑15.4)
13.8
(9.23‑18.6)
15.6
(10.2‑21.4)
7-day
4.42
(3.67‑5.24)
5.23
(4.34‑6.21)
6.56
(5.43‑7.81)
7.67
(6.30‑9.16)
9.19
(7.29‑11.4)
10.3
(8.01‑13.0)
11.5
(8.67‑15.0)
13.0
(9.12‑17.0)
15.1
(10.2‑20.3)
16.9
(11.1‑23.1)
10-day
5.11
(4.27‑6.03)
5.96
(4.98‑7.04)
7.35
(6.11‑8.70)
8.50
(7.02‑10.1)
10.1
(8.03‑12.4)
11.3
(8.77‑14.1)
12.5
(9.42‑16.1)
14.0
(9.87‑18.2)
16.1
(10.9‑21.5)
17.9
(11.7‑24.2)
20-day
7.25
(6.13‑8.47)
8.16
(6.89‑9.54)
9.65
(8.11‑11.3)
10.9
(9.09‑12.8)
12.6
(10.1‑15.2)
13.9
(10.9‑17.0)
15.2
(11.4‑19.1)
16.6
(11.8‑21.3)
18.5
(12.6‑24.4)
20.0
(13.2‑26.8)
30-day
9.03
(7.68‑10.5)
9.99
(8.49‑11.6)
11.5
(9.77‑13.5)
12.8
(10.8‑15.0)
14.6
(11.8‑17.5)
16.0
(12.6‑19.5)
17.4
(13.1‑21.6)
18.7
(13.4‑23.9)
20.5
(14.0‑26.8)
21.8
(14.4‑29.0)
45-day
11.2
(9.63‑13.0)
12.3
(10.5‑14.2)
13.9
(11.9‑16.1)
15.3
(12.9‑17.8)
17.2
(13.9‑20.4)
18.7
(14.7‑22.5)
20.1
(15.1‑24.7)
21.4
(15.4‑27.1)
23.0
(15.8‑29.9)
24.1
(16.0‑31.9)
60-day
13.1
(11.3‑15.1)
14.2
(12.2‑16.3)
15.9
(13.6‑18.4)
17.4
(14.7‑20.1)
19.4
(15.7‑22.9)
21.0
(16.5‑25.1)
22.4
(16.9‑27.3)
23.7
(17.1‑29.9)
25.2
(17.4‑32.7)
26.2
(17.5‑34.5)
1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).
Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency
estimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at
upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values.
Please refer to NOAA Atlas 14 document for more information.
Back to Top
PF graphical

NOAA Atlas 14, Volume 10, Version 3
Location name: Town of Waterford, Connecticut,
USA*
Latitude: 41.3325°, Longitude: -72.1669°
Elevation: 116 ft**
* source: ESRI Maps
** source: USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
Sanja Perica, Sandra Pavlovic, Michael St. Laurent, Carl Trypaluk, Dale Unruh, Orlan Wilhite
NOAA, National Weather Service, Silver Spring, Maryland
PF_tabular | PF_graphical | Maps_&_aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches/hour)1
Duration
Average recurrence interval (years)
1
2
5
10
25
50
100
200
500
1000
5-min
4.03
(3.11‑5.12)
4.82
(3.72‑6.13)
6.12
(4.70‑7.81)
7.20
(5.50‑9.22)
8.68
(6.44‑11.5)
9.79
(7.13‑13.2)
11.0
(7.78‑15.3)
12.3
(8.27‑17.3)
14.3
(9.24‑20.6)
15.9
(10.1‑23.4)
10-min
2.85
(2.20‑3.63)
3.41
(2.63‑4.35)
4.34
(3.33‑5.53)
5.10
(3.89‑6.53)
6.15
(4.56‑8.16)
6.94
(5.05‑9.36)
7.77
(5.51‑10.8)
8.72
(5.86‑12.3)
10.1
(6.55‑14.6)
11.3
(7.14‑16.5)
15-min
2.24
(1.72‑2.84)
2.68
(2.06‑3.41)
3.40
(2.62‑4.34)
4.00
(3.06‑5.12)
4.82
(3.58‑6.40)
5.44
(3.96‑7.34)
6.09
(4.32‑8.48)
6.84
(4.59‑9.62)
7.94
(5.14‑11.5)
8.85
(5.60‑13.0)
30-min
1.58
(1.22‑2.01)
1.89
(1.46‑2.41)
2.40
(1.84‑3.06)
2.82
(2.16‑3.62)
3.40
(2.52‑4.51)
3.84
(2.79‑5.18)
4.29
(3.04‑5.97)
4.82
(3.24‑6.78)
5.59
(3.62‑8.07)
6.22
(3.94‑9.13)
60-min
1.02
(0.789‑1.30)
1.22
(0.942‑1.56)
1.55
(1.19‑1.98)
1.82
(1.39‑2.33)
2.20
(1.63‑2.91)
2.48
(1.80‑3.34)
2.77
(1.96‑3.85)
3.11
(2.09‑4.37)
3.60
(2.33‑5.20)
4.01
(2.54‑5.88)
2-hr
0.670
(0.522‑0.845)
0.802
(0.624‑1.01)
1.02
(0.789‑1.29)
1.20
(0.923‑1.52)
1.44
(1.08‑1.90)
1.63
(1.20‑2.18)
1.82
(1.30‑2.52)
2.05
(1.38‑2.86)
2.38
(1.55‑3.41)
2.66
(1.69‑3.86)
3-hr
0.518
(0.405‑0.649)
0.620
(0.485‑0.777)
0.786
(0.613‑0.989)
0.924
(0.716‑1.17)
1.11
(0.838‑1.46)
1.26
(0.927‑1.67)
1.41
(1.01‑1.93)
1.58
(1.07‑2.19)
1.84
(1.20‑2.62)
2.06
(1.31‑2.97)
6-hr
0.330
(0.261‑0.410)
0.394
(0.311‑0.490)
0.499
(0.393‑0.622)
0.586
(0.459‑0.733)
0.706
(0.536‑0.915)
0.796
(0.592‑1.05)
0.891
(0.644‑1.21)
1.00
(0.683‑1.37)
1.16
(0.764‑1.64)
1.30
(0.834‑1.86)
12-hr
0.203
(0.162‑0.250)
0.242
(0.193‑0.298)
0.306
(0.243‑0.378)
0.359
(0.284‑0.445)
0.432
(0.331‑0.555)
0.487
(0.365‑0.635)
0.545
(0.397‑0.733)
0.612
(0.420‑0.831)
0.711
(0.469‑0.991)
0.793
(0.511‑1.12)
24-hr
0.119
(0.096‑0.145)
0.143
(0.115‑0.174)
0.182
(0.146‑0.222)
0.214
(0.171‑0.263)
0.258
(0.199‑0.329)
0.291
(0.220‑0.377)
0.327
(0.240‑0.437)
0.368
(0.254‑0.496)
0.430
(0.285‑0.594)
0.483
(0.312‑0.677)
2-day
0.066
(0.054‑0.080)
0.080
(0.065‑0.097)
0.103
(0.084‑0.125)
0.122
(0.099‑0.149)
0.149
(0.116‑0.188)
0.168
(0.128‑0.216)
0.189
(0.141‑0.252)
0.215
(0.149‑0.286)
0.254
(0.169‑0.347)
0.287
(0.186‑0.398)
3-day
0.048
(0.039‑0.057)
0.058
(0.047‑0.069)
0.074
(0.060‑0.089)
0.088
(0.071‑0.106)
0.107
(0.084‑0.134)
0.121
(0.093‑0.154)
0.136
(0.101‑0.180)
0.154
(0.107‑0.204)
0.182
(0.122‑0.248)
0.206
(0.134‑0.284)
4-day
0.038
(0.031‑0.046)
0.046
(0.038‑0.055)
0.059
(0.048‑0.071)
0.070
(0.057‑0.084)
0.084
(0.066‑0.106)
0.095
(0.073‑0.121)
0.107
(0.080‑0.141)
0.121
(0.085‑0.160)
0.143
(0.096‑0.194)
0.162
(0.105‑0.222)
7-day
0.026
(0.021‑0.031)
0.031
(0.025‑0.036)
0.039
(0.032‑0.046)
0.045
(0.037‑0.054)
0.054
(0.043‑0.067)
0.061
(0.047‑0.077)
0.068
(0.051‑0.089)
0.077
(0.054‑0.100)
0.089
(0.060‑0.120)
0.100
(0.066‑0.137)
10-day
0.021
(0.017‑0.025)
0.024
(0.020‑0.029)
0.030
(0.025‑0.036)
0.035
(0.029‑0.042)
0.042
(0.033‑0.051)
0.046
(0.036‑0.058)
0.052
(0.039‑0.067)
0.058
(0.041‑0.075)
0.067
(0.045‑0.089)
0.074
(0.048‑0.100)
20-day
0.015
(0.012‑0.017)
0.016
(0.014‑0.019)
0.020
(0.016‑0.023)
0.022
(0.018‑0.026)
0.026
(0.021‑0.031)
0.028
(0.022‑0.035)
0.031
(0.023‑0.039)
0.034
(0.024‑0.044)
0.038
(0.026‑0.050)
0.041
(0.027‑0.055)
30-day
0.012
(0.010‑0.014)
0.013
(0.011‑0.016)
0.016
(0.013‑0.018)
0.017
(0.014‑0.020)
0.020
(0.016‑0.024)
0.022
(0.017‑0.027)
0.024
(0.018‑0.029)
0.025
(0.018‑0.033)
0.028
(0.019‑0.037)
0.030
(0.020‑0.040)
45-day
0.010
(0.008‑0.012)
0.011
(0.009‑0.013)
0.012
(0.010‑0.014)
0.014
(0.011‑0.016)
0.015
(0.012‑0.018)
0.017
(0.013‑0.020)
0.018
(0.014‑0.022)
0.019
(0.014‑0.025)
0.021
(0.014‑0.027)
0.022
(0.014‑0.029)
60-day
0.009
(0.007‑0.010)
0.009
(0.008‑0.011)
0.011
(0.009‑0.012)
0.012
(0.010‑0.013)
0.013
(0.010‑0.015)
0.014
(0.011‑0.017)
0.015
(0.011‑0.018)
0.016
(0.011‑0.020)
0.017
(0.012‑0.022)
0.018
(0.012‑0.023)
1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).
Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for
a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not
checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values.
Please refer to NOAA Atlas 14 document for more information.
Back to Top
PF graphical

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
APPENDIX D 
Test Pit & Infiltration Logs 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

DANIELS      AVENUE
Date: 4/21/2025  Time: 15:47  User: ochasse  Style Table: Langan.stb  Layout: Layout1
Document Code: 140310301-0201-BL101-0101
www.langan.com
555 Long Wharf Drive, 9th Floor
New Haven, CT 06511
T: 203.562.5771F: 203.789.6142
Langan CT, Inc.
©
Langan
2024

SYMBOL
Elev.
(ft)
+109.0
+108.0
+104.0
+103.0
+99.0
DESCRIPTION
Brown Silty fine SAND, trace fine gravel, trace root (moist) 
[TOPSOIL]
Brown medium to fine SAND, trace boulder, trace fine gravel, 
trace silt, trace brick, trace metal (moist) [FILL]
Dark brown SILT, trace medium to fine sand, trace root (moist) 
[BURIED TOPSOIL]
Grayish brown fine to coarse SAND, trace coarse to fine 
gravel, trace silt (moist) [TILL]
End of Test Pit at 10.0ft.
Depth
Scale
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
SAMPLE
Number
Type
REMARKS
G-1 from 2ft to 2.5ft
Infiltration test performed at about 6ft below grade.
G-2 from 5.5ft to 6ft
Perched groundwater flowing in from test pit sidewall at 7ft; G-3 
from 6.5ft to 7ft
Mottling observed from 6ft to 10ft
G-4 from 8.5ft to 9ft
G-5 from 9.5ft to 10ft
Groundwater pooling at 10ft. Bottom of test pit at 10ft. Test pit 
backfilled to grade in lifts of the excavated material and tamped 
with the excavator bucket.
Log of Test Pit
TP-04
Sheet     1     of     1
Project
Project No.
Date
LEARN - Newman Architects
140310301
4/16/2025
Location
Elevation and Datum
51 Daniel's Ave, Waterford, Connecticut
Approx. el. + 109.0 (NAVD 88)
Excavation Company
Depth
Water Level - First
Water Level - Completion
Polster Industries, LLC
10.0 ft
10.0
N/A
Excavation Equipment
Excavation Foreman
Field Engineer
Kubota KX080-4 Mini Excavator 
Ben Ignace 
Shawn OConnor
Langan Cloud Database, Project : 140310301, LEARN - Newman Architects. Produced at 04/23/2025 19:27:19

INFILTRATION TESTS
PROJECT
LOCATION
INSPECTOR
PRESOAK
TIME
Start
10:23
Approx.
109
End
11:40
Approx.
105
Approx.
103
METHOD OF INFILTRATION TEST
TIME (MIN)
DEPTH TO 
WATER (IN)
DROP (IN)
RATE
(IN/MIN)
RATE 
(IN/HOUR)
0
1
-
-
15
10.5
9.5
0.63
38
30
13.5
3
0.20
12
45
15.5
2
0.13
8
60
16.5
1
0.07
4
15.5
TIME (MIN)
WATER LEVEL 
(IN)
DROP (IN)
RATE
(IN/MIN)
RATE 
(IN/HOUR)
0
1
-
-
15
9.5
8.5
0.57
34.0
30
12.5
3
0.20
12.0
45
14.5
2
0.13
8.0
60
16
1.5
0.10
6.0
15.0
TIME (MIN)
WATER LEVEL 
(IN)
DROP (IN)
RATE
(IN/MIN)
RATE 
(IN/HOUR)
0
1
-
-
15
9
8
0.53
32.0
30
12.5
3.5
0.23
14.0
-
-
-
-
-
-
-
-
-
-
23.0
17.8
IT-04 in TP-04 Basin 5A
LEARN
PROJECT NO.
140310301
Waterford, CT 
DATE
16 April 2025
Shawn O'Connor 
WEATHER
Partly Sunny, 45-52°F
DEPTH OF HOLE (INCH)
ELEVATION AND DATUM
24
Surface Elevation
(NAVD88)
24
Top of Hole Elevation
(NAVD88)
Bottom of Hole Elevation
(NAVD88)
SOIL CONDITIONS
TEST 1 @ 11:56
Grayish brown fine to coarse SAND, trace coarse to fine 
gravel, trace silt [TILL]
Average Rate:
TP-04 was advanced to a depth of about 10 feet below existing grades. The test pit benched to the side of the pit about 4 feet below grade. A 24-inch deep and about 6-inch 
diameter hole was dug by hand with a post hole digger. A 25-inch long pipe with a 4-inch diameter was inserted into the hole. The hole was presoaked for about 1 hour with 
24-inches of water. At the end of the presoak, about 16-inches of water had infiltrated. For each infiltration test, the hole was filled with water to a predetermined depth. 
Then, after every 15 minutes, the depth to water was measured to calculate the total drop of water over that time period. The tables below outline the calculations for 
determining the average rate in which the water dissipated.
Average Rate:
inches/hour
SOIL CONDITIONS
TEST 2 @ 1:05
Grayish brown fine to coarse SAND, trace coarse to fine 
gravel, trace silt [TILL]
Average Rate:
SOIL CONDITIONS
TEST 3 @ 2:06
Grayish brown fine to coarse SAND, trace coarse to fine 
gravel, trace silt [TILL]
Average Rate:
\\langan.com\data\NHV\data3\140310301\Project Data\_Discipline\Geotechnical\Field Records\Infiltration Testing\Infiltration Tests 
Rev.xlsxTP-04