Conservation Commission - 1072 (05/08/2025)

01 May 2025 
 
Gary Schneider 
Town of Waterford 
1000 Hartford Turnpike 
Waterford, CT 06385 
 
RE:
 
Stormwater Management Report 
LEARN Early Childhood School 
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 conveyance system at 51 Daniels Avenue.  
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 site is currently occupied by an existing school and includes impervious, 
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 west, the project site is bordered by residential properties on High Street 
and High Ridge Drive, to the south by residential properties on Seaview Terrace and the Bayview 
Healthcare building, and to the east by residential properties and wooded areas. To the north, the 
project site is bordered by Daniels Avenue. The existing project site is currently a closed school 
building with associated impervious parking, drive aisles and pervious areas with the majority of 
stormwater running overland towards off-site wetlands to the west or Daniels Avenue.  
Based upon a topographic survey titled “Lot Line Modification Survey” prepared by Benesch, 
dated March 28, 2024, the site grades generally slope downward from the eastern property line 
towards High Street and the off-site wetland to the west, with a small northeastern portion of 
the site sloping downward towards the northeast wetland. Elevations range from approximately 
120 feet to about 80 feet. 

Stormwater Management Report 
LEARN Early Childhood School 
Waterford, Connecticut 
Langan Project No.: 140310301 
01 May 2025
Page 2 of 9 
 
 
 
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 Woodbridge fine sandy loam with 
a D hydrologic rating with slopes between 0% and 3%, Paxton and Montauk fine sandy loams 
with a C hydrologic rating with slopes between 3% and 8%, or Urban land with a D hydrologic 
rating.  Additionally, small portions of the site are classified as Woodbridge fine sandy loam with 
a D hydrologic rating with slopes between 3% and 8%, Paxton and Montauk fine sandy loams 
with a C hydrologic rating with slopes between 3% and 8%, very stony, and Charlton-Chatfield 
complex with a B hydrologic rating with slopes between 0% and 15%, very rocky. 
There is one off-site wetland is located off the southwest corner of the site. No site work is 
proposed within the 100-foot upland review area of this wetland or within the 100-foot vernal 
pool envelope. Another off-site wetland is located off the southeastern corner of the site. A small 
section of sidewalk is proposed within the upland review area of this wetland, however, the 
sidewalk is downgradient of this wetland and no direct impacts are proposed. A small portion of 
a vernal is located on the parcel to be retained by the Town of Waterford. No permanent site 
features will be located within the 100-ft vernal pool envelope. No direct impacts are proposed. 
Proposed Project 
The proposed project consists of the construction of a ±87,500 square-foot footprint early 
childhood school. Additional improvements include new driveways, parking areas, stormwater 
and utility infrastructure, as well as hardscape and landscaped areas. A summary of the change 
in impervious is shown below. 
Project Site Impervious Cover [SF] 
Existing Conditions 
Proposed Conditions 
Net Increase 
±162,430 
±319,660 
±157,230 

Stormwater Management Report 
LEARN Early Childhood School 
Waterford, Connecticut 
Langan Project No.: 140310301 
01 May 2025
Page 3 of 9 
 
 
 
The proposed stormwater system has been designed to maintain existing site hydrology to the 
maximum extent practicable.  The majority of runoff from the new development will be collected 
in a traditional pipe and catchbasin network and conveyed to various stormwater management 
systems before discharging to either the southwestern property boundary or to the existing 
storm sewer system in Daniels Avenue. Water quality improvements include catchbasins with 
sumps, water quality unit, and underground and aboveground detention systems with outlet 
control structures. The These water quality improvements have been designed to meet the 
minimum average annual pollutant load reduction targets for redevelopment sites per Table 4.3 
of the 2024 CT Stormwater Quality Manual.  
Details of the size and location of the stormwater network can be found on the Grading & 
Drainage Plans, detail sheets, and supporting calculations in the appendices of this report. 
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.   
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 
Woodbridge fine sandy loam with a “D” hydrologic rating, Paxton and Montauk fine sandy loams 
with a “C” hydrologic rating, or Urban land with a “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 

Stormwater Management Report 
LEARN Early Childhood School 
Waterford, Connecticut 
Langan Project No.: 140310301 
01 May 2025
Page 4 of 9 
 
 
 
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 
 
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 Watersheds 1, 2, and 3 (See 
Drawing EXWS).  
Existing Watershed 1 is approximately 8.21 acres and consists mostly of grassy and wooded 
areas south of the existing school. Stormwater runoff from this watershed flows overland to the 
west and towards the off-site western wetland.  
Existing Watershed 2 is approximately 5.53 acres and consists of the existing school parking area 
and grass areas west of the school. Stormwater runoff from this watershed flows overland to 
the northwest and towards the stormwater network within Daniels Avenue. 

Stormwater Management Report 
LEARN Early Childhood School 
Waterford, Connecticut 
Langan Project No.: 140310301 
01 May 2025
Page 5 of 9 
 
 
 
Existing Watershed 3 is approximately 2.56 acres and consists mostly of grassy and paved areas 
east of the existing school. Stormwater runoff from this watershed flows overland to the 
northeastern 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 has been divided into two sub-watersheds: Proposed Watershed 1A and 
Proposed Watershed 1B. Proposed Watershed 1A is about 3.81 acres and consists of the 
southern parking lot and some landscape areas. Stormwater from these areas will be collected 
in a series of catch basins before being directed to a proposed underground infiltration system 
(System 1A). Discharge from this system will then be routed to an outfall located to the 
southwest. Proposed Watershed 1B is about 2.86 acres and consists of mostly grassy and some 
hardscaped areas. Stormwater from these areas will continue to flow west, overland, to the 
existing off-site wetland. 
Proposed Watershed 2 has been divided into three sub-watersheds: Proposed Watershed 2A, 
Proposed Watershed 2B, and Proposed Watershed 2C. Proposed Watershed 2A is about 3.41 
acres and consists mostly of roof tops, amenity and some landscape areas. Stormwater from 
these areas will be collected in roof drains and a series of yard drains before being directed to a 
proposed aboveground infiltration basin (System 2A). Discharge from this system will then be 
routed to the existing stormwater system in Daniels Avenue. Proposed Watershed 2B is about 
3.19 acres and consists of the northern parking lot, site driveway, roof tops, amenity and some 
landscape areas. Stormwater from these areas will be collected in roof drains and a series of 
catch basins before being direct to a proposed underground infiltration basin (System 2B). 
Discharge from this system will then be routed to the existing stormwater system in Daniels 
Avenue. Proposed Watershed 2C is about 1.68 acres and consists of mostly grassy areas. 
Stormwater from these areas will continue to flow northwest, overland, to the existing 
stormwater system in Daniels Avenue. 
Proposed Watershed 3 is about 1.35 acres and consists mostly of grassy and wooded areas. 
Stormwater from these areas will continue to flow northeast, overland, to the northeastern 
wetland. 
Details of the sizes and locations of the stormwater collection systems can be found on drawings 
CG101 and CG102. On-site infiltration test was performed on April 16th, 2025, by Langan 
Engineering. Refer to Appendix F for test locations, results and test pit information. A 50% 
reduction was applied to the slowest test result for each system, see summary table below. 
 

Stormwater Management Report 
LEARN Early Childhood School 
Waterford, Connecticut 
Langan Project No.: 140310301 
01 May 2025
Page 6 of 9 
 
 
 
Detention System
Design Infiltration Rate
1A 
2 in/hr 
2A 
0.25 in/hr 
2B 
2 in/hr 
 
Site Discharge Peak Flow Comparison for WS-1 (CF) 
Storm 
Current 
Proposed 
Delta 
% Reduction 
2-Year 
10.65 
5.03 
-5.62 
-53% 
10-Year 
20.01 
13.53 
-6.48 
-32% 
25-Year 
26.08 
18.28 
-7.80 
-30% 
100-Year 
35.44 
28.67 
-6.77 
-19% 
Site Discharge Peak Flow Comparison for WS-2 (CF) 
Storm 
Current 
Proposed 
Delta 
% Reduction 
2-Year 
10.97 
4.78 
-6.19 
-56% 
10-Year 
18.68 
10.58 
-8.10 
-43% 
25-Year 
23.53 
17.35 
-6.18 
-26% 
100-Year 
30.92 
24.24 
-6.68 
-22% 
Site Discharge Peak Flow Comparison for WS-3 (CF) 
Storm 
Current 
Proposed 
Delta 
% Reduction 
2-Year 
4.62 
1.69 
-2.93 
-63% 
10-Year 
8.34 
3.51 
-4.83 
-58% 
25-Year 
10.73 
4.74 
-5.99 
-56% 
100-Year 
14.39 
6.67 
-7.72 
-54% 
 
Site Discharge Peak Flow Comparison for Total Site (CF) 
Storm 
Current 
Proposed 
Delta 
% Reduction 
2-Year 
25.00 
10.37 
-14.51 
-58% 
10-Year 
44.96 
24.83 
-19.81 
-44% 
25-Year 
57.76 
37.84 
-19.46 
-34% 
100-Year 
77.45 
58.86 
-17.89 
-23% 
 
As can be seen from the tables above, runoff from each watershed and the total site will be 
reduced for the storms up to, and including, the 100-year storm.  Additionally, per the 2024 CT 
Stormwater Quality Manual requirements, runoff from each watershed that includes proposed 
site development will be reduced by 50% for the 2-year storm event. 
 

Stormwater Management Report 
LEARN Early Childhood School 
Waterford, Connecticut 
Langan Project No.: 140310301 
01 May 2025
Page 7 of 9 
 
 
 
STORMWATER CONVEYANCE SYSTEM (See Appendix D) 
The stormwater conveyance system was sized using the Rational Method for the 10-year storm 
event.  Values for area, runoff coefficient, C, and a time of concentration were calculated for each 
drainage area.  The average runoff coefficient was calculated based upon the following cover 
types: 
 
Cover 
C 
 
Grass/Pervious 
0.3 
 
Roof/Pavement/Impervious  
0.9 
Rainfall intensities were taken from the “NOAA Atlas 14 Point Precipitation Frequency Estimates: 
CT”. Stormwater pipes were then sized based upon the Manning’s Equation for full flow pipe 
capacity and solving for the hydraulic grade line.  The computer program Hydraflow Storm Sewers 
2011 by Intellisolve was used in the analysis. 
The proposed storm sewer system has been analyzed sing a starting HGL elevation equal to the 
outlet pipe’s crown elevation. This mimics a tailwater elevation equal to the outlet pipe’s diameter 
or a scenario where a proposed pipe is entering an existing pipe flow at full capacity. 
STORMWATER QUALITY (See Appendix E) 
The proposed stormwater management system has been designed to incorporate stormwater 
quality measures including catch basins with sumps, water quality units, underground and 
aboveground detention systems with outlet control structures. These measures will be 
implemented to increase water quality, maintain pre-development hydrology and minimize the 
passage of pollutants to the existing stormwater systems as compared to current conditions to 
the maximum extent achievable.  
Standard 2 - Stormwater Runoff Quantity Control, was prioritized due to concerns about 
discharge upgradient of residential properties and the limited capacity of the existing storm sewer 
network in Daniels Avenue. Therefore, due to the site’s presence of groundwater and low 
infiltration rates, the stormwater runoff volume retained on-site (as dead storage) does not meet 
the required retention volume (100% of the site’s WQV). However, per the 2022 New England 
Stormwater Retrofit Manual performance curves for infiltration basin (HSG C & D), the retention 
volumes provided exceeds the required minimum average annual pollutant load reduction 
requirements for redevelopment sites listed in Table 4.3 of the CT Stormwater Quality Manual. 
The WQV is fully infiltrated for all design storms across the site, except for Pond 2A, where the 

Stormwater Management Report 
LEARN Early Childhood School 
Waterford, Connecticut 
Langan Project No.: 140310301 
01 May 2025
Page 8 of 9 
 
 
 
infiltration rate does not make it feasible due to poor infiltration rates. A summary of the retention 
volume (as dead storage) for each stormwater basin is summarized below (see Appendix E). 
Detention System
2022 NE Stormwater Retrofit
Minimum Retention Volume 
Provided Retention Volume 
1A 
1,689 CF 
1,809 CF
2A 
3,576 CF 
3,651 CF
2B 
2,832 CF 
2,891 CF
Each water quality unit has been sized to treat the water quality flow for 100% of the WQV. We 
will utilize Contech CDS hydrodynamic separators (water quality units) as pretreatment units, 
which are rated to provide 80% TSS removal. Additionally, per the New England Stormwater 
Retrofit Manual, the retention volume provided by pond 1A provides 80% TSS removal and ponds 
2A and 2B provide 92% TSS removal. 
CONCLUSION 
The proposed stormwater management system has been designed in general accordance with 
the 2024 CTDEEP Stormwater Quality Manual, 2000 CTDOT Drainage Manual, and the Town of 
Waterford ordinances for stormwater management (Section 25.6). It has been designed to mimic 
existing site hydrology to the maximum extent practicable with no increase in the peak flow rates.   
This Langan report confirms that the proposed stormwater management system, as designed, 
will effectively manage quality and quantity of stormwater runoff for the proposed development. 
Please refer to the Drawings for additional drainage information. 
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 - LEARN\Report Template.docx 

Stormwater Management Report 
LEARN Early Childhood School 
Waterford, Connecticut 
Langan Project No.: 140310301 
01 May 2025
Page 9 of 9 
 
 
 
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 
 
DACB  
 
Drainage Area Catchment Basin Map 
 
REFERENCE DRAWINGS 
 
CG100  
 
Overall Grading & Drainage Plan 
 
CG101  
 
Grading & Drainage Plan I 
 
CG102  
 
Grading & Drainage Plan II 
 
CE100  
 
Overall Soil Erosion & Sediment Control Plan 
 
CE101  
 
Soil Erosion & Sediment Control Plan I 
 
CE102  
 
Soil Erosion & Sediment Control Plan II 
 
LIST OF APPENDICES 
 
 
Appendix A  
Existing Stormwater Discharge Calculations 
Appendix B  
Proposed Stormwater Discharge Calculations 
Appendix C  
NOAA Rainfall Data 
Appendix D  
Stormwater Collection System Calculations 
Appendix E 
 
Supporting Calculations 
Appendix F 
 
Test Pit & Infiltration Logs 
Appendix G 
Stormwater Management System Operation and 
Maintenance Plan 
 

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

HIGH     STREET
DANIELS      AVENUE
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555 Long Wharf Drive, 9th Floor
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T: 203.562.5771F: 203.789.6142
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©
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2024

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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

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Document Code: 140310301-0503-CG104-0103
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

OVERALL
GRADING AND
DRAINAGE PLAN
CG100
05/01/2025
KEG
BTW
Date: 4/30/2025  Time: 14:00  User: bwillsey  Style Table: Langan.stb  Layout: CG100 Document Code: 140310301-0504-CG101-0101
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
20240069
51 DANIELS AVE,
WATERFORD, CT 06385
LEARN - EARLY
CHILDHOOD SCHOOL
WATERFORD CONSERVATION
SUBMISSION
As indicated
STATE PROJECT NUMBER:
245-0090 MAG/N/PF

OVERALL SOIL EROSION
& SEDIMENT CONTROL
PLAN
CE100
05/01/2025
KEG
BTW
Date: 4/30/2025  Time: 14:02  User: bwillsey  Style Table: Langan.stb  Layout: CE100 Document Code: 140310301-0504-CE101-0101
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
20240069
51 DANIELS AVE,
WATERFORD, CT 06385
LEARN - EARLY
CHILDHOOD SCHOOL
WATERFORD CONSERVATION
SUBMISSION
As indicated
STATE PROJECT NUMBER:
245-0090 MAG/N/PF

SOIL EROSION &
SEDIMENT
CONTROL PLAN I
CE101
05/01/2025
KEG
BTW
Date: 4/30/2025  Time: 14:11  User: bwillsey  Style Table: Langan.stb  Layout: CE101 Document Code: 140310301-0504-CE101-0102
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
20240069
51 DANIELS AVE,
WATERFORD, CT 06385
LEARN - EARLY
CHILDHOOD SCHOOL
WATERFORD CONSERVATION
SUBMISSION
As indicated
STATE PROJECT NUMBER:
245-0090 MAG/N/PF

SOIL EROSION &
SEDIMENT
CONTROL PLAN II
CE102
05/01/2025
KEG
BTW
Date: 4/30/2025  Time: 15:26  User: bwillsey  Style Table: Langan.stb  Layout: CE102 Document Code: 140310301-0504-CE101-0103
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/N/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
20240069
51 DANIELS AVE,
WATERFORD, CT 06385
LEARN - EARLY
CHILDHOOD SCHOOL
WATERFORD PLANNING AND
ZONING COMMISSION
As indicated

GRADING AND
DRAINAGE PLAN I
CG101
05/01/2025
KEG
BTW
Date: 4/30/2025  Time: 14:00  User: bwillsey  Style Table: Langan.stb  Layout: CG101 Document Code: 140310301-0504-CG101-0102
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
20240069
51 DANIELS AVE,
WATERFORD, CT 06385
LEARN - EARLY
CHILDHOOD SCHOOL
WATERFORD CONSERVATION
SUBMISSION
As indicated
STATE PROJECT NUMBER:
245-0090 MAG/N/PF

GRADING AND
DRAINAGE PLAN II
CG102
05/01/2025
KEG
BTW
Date: 4/30/2025  Time: 14:00  User: bwillsey  Style Table: Langan.stb  Layout: CG102 Document Code: 140310301-0504-CG101-0103
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
20240069
51 DANIELS AVE,
WATERFORD, CT 06385
LEARN - EARLY
CHILDHOOD SCHOOL
WATERFORD CONSERVATION
SUBMISSION
As indicated
STATE PROJECT NUMBER:
245-0090 MAG/N/PF

 
 
APPENDIX A 
Existing Stormwater Discharge Calculations 
 
 

EXWS-1
EXWS-2
EXWS-3
Site
Routing Diagram for EX WS_Conservation Submission
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_Conservation Submission
  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)
0.13
69
50-75% Grass cover, Fair, HSG B  (EXWS-2, EXWS-3)
3.33
79
50-75% Grass cover, Fair, HSG C  (EXWS-1, EXWS-2)
6.01
84
50-75% Grass cover, Fair, HSG D  (EXWS-1, EXWS-2, EXWS-3)
3.73
98
Impervious  (EXWS-1, EXWS-2, EXWS-3)
0.29
55
Woods, Good, HSG B  (EXWS-1, EXWS-3)
1.82
70
Woods, Good, HSG C  (EXWS-1, EXWS-2)
0.99
77
Woods, Good, HSG D  (EXWS-1, EXWS-2, EXWS-3)
16.30
84
TOTAL AREA

NOAA 24-hr D  2-Year Rainfall=3.44"
EX WS_Conservation Submission
  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=0.05 hrs, 961 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=357,584 sf   8.39% Impervious   Runoff Depth=1.66"
Subcatchment EXWS-1: 
   Flow Length=560'   Tc=18 min   CN=81   Runoff=10.65 cfs  49,469 CF
Runoff Area=240,801 sf   39.65% Impervious   Runoff Depth=2.13"
Subcatchment EXWS-2: 
   Flow Length=687'   Tc=12 min   CN=87   Runoff=10.97 cfs  42,714 CF
Runoff Area=111,601 sf   33.10% Impervious   Runoff Depth=1.81"
Subcatchment EXWS-3: 
   Flow Length=295'   Tc=10 min   CN=83   Runoff=4.62 cfs  16,816 CF
   Inflow=24.88 cfs  108,999 CF
Link Site: 
   Primary=24.88 cfs  108,999 CF
Total Runoff Area = 16.30 ac   Runoff Volume = 108,999 CF   Average Runoff Depth = 1.84"
77.12% Pervious = 12.57 ac     22.88% Impervious = 3.73 ac

NOAA 24-hr D  2-Year Rainfall=3.44"
EX WS_Conservation Submission
  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
=
10.65 cfs @ 12.28 hrs,  Volume=
49,469 CF,  Depth= 1.66"
     Routed to Link Site : 
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs
NOAA 24-hr D  2-Year Rainfall=3.44"
Area (sf)
CN
Description
*
30,013
98
Impervious
0
69
50-75% Grass cover, Fair, HSG B
76,186
79
50-75% Grass cover, Fair, HSG C
173,587
84
50-75% Grass cover, Fair, HSG D
784
55
Woods, Good, HSG B
62,291
70
Woods, Good, HSG C
14,723
77
Woods, Good, HSG D
357,584
81
Weighted Average
327,571
91.61% Pervious Area
30,013
8.39% Impervious Area
Tc
Length
Slope
Velocity
Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
5
28
0.0666
0.10
Sheet Flow, AB
Woods: Light underbrush   n= 0.400   P2= 3.44"
0
12
0.0666
1.51
Sheet Flow, BC
Smooth surfaces   n= 0.011   P2= 3.44"
5
90
0.0667
0.28
Sheet Flow, CD
Grass: Short   n= 0.150   P2= 3.44"
3
20
0.0200
0.13
Sheet Flow, DE
Grass: Short   n= 0.150   P2= 3.44"
3
180
0.0150
0.86
Shallow Concentrated Flow, EF
Short Grass Pasture   Kv= 7.0 fps
2
230
0.0667
1.81
Shallow Concentrated Flow, FG
Short Grass Pasture   Kv= 7.0 fps
18
560
Total

NOAA 24-hr D  2-Year Rainfall=3.44"
EX WS_Conservation Submission
  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)
11
10
9
8
7
6
5
4
3
2
1
0
NOAA 24-hr D
2-Year Rainfall=3.44"
Runoff Area=357,584 sf
Runoff Volume=49,469 CF
Runoff Depth=1.66"
Flow Length=560'
Tc=18 min
CN=81
10.65 cfs

NOAA 24-hr D  2-Year Rainfall=3.44"
EX WS_Conservation Submission
  Printed  4/28/2025
Prepared by Langan Engineering
Page 6
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Summary for Subcatchment EXWS-2: 
Runoff
=
10.97 cfs @ 12.20 hrs,  Volume=
42,714 CF,  Depth= 2.13"
     Routed to Link Site : 
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs
NOAA 24-hr D  2-Year Rainfall=3.44"
Area (sf)
CN
Description
*
95,484
98
Impervious
3,180
69
50-75% Grass cover, Fair, HSG B
68,825
79
50-75% Grass cover, Fair, HSG C
56,323
84
50-75% Grass cover, Fair, HSG D
0
55
Woods, Good, HSG B
16,771
70
Woods, Good, HSG C
218
77
Woods, Good, HSG D
240,801
87
Weighted Average
145,317
60.35% Pervious Area
95,484
39.65% Impervious Area
Tc
Length
Slope
Velocity
Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
0
24
0.0120
0.87
Sheet Flow, AB
Smooth surfaces   n= 0.011   P2= 3.44"
1
126
0.0833
2.64
Sheet Flow, BC
Smooth surfaces   n= 0.011   P2= 3.44"
2
145
0.0300
1.21
Shallow Concentrated Flow, CD
Short Grass Pasture   Kv= 7.0 fps
9
392
0.0120
0.77
Shallow Concentrated Flow, DE
Short Grass Pasture   Kv= 7.0 fps
12
687
Total

NOAA 24-hr D  2-Year Rainfall=3.44"
EX WS_Conservation Submission
  Printed  4/28/2025
Prepared by Langan Engineering
Page 7
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Subcatchment EXWS-2: 
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)
12
11
10
9
8
7
6
5
4
3
2
1
0
NOAA 24-hr D
2-Year Rainfall=3.44"
Runoff Area=240,801 sf
Runoff Volume=42,714 CF
Runoff Depth=2.13"
Flow Length=687'
Tc=12 min
CN=87
10.97 cfs

NOAA 24-hr D  2-Year Rainfall=3.44"
EX WS_Conservation Submission
  Printed  4/28/2025
Prepared by Langan Engineering
Page 8
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Summary for Subcatchment EXWS-3: 
Runoff
=
4.62 cfs @ 12.17 hrs,  Volume=
16,816 CF,  Depth= 1.81"
     Routed to Link Site : 
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs
NOAA 24-hr D  2-Year Rainfall=3.44"
Area (sf)
CN
Description
*
36,939
98
Impervious
2,483
69
50-75% Grass cover, Fair, HSG B
0
79
50-75% Grass cover, Fair, HSG C
31,886
84
50-75% Grass cover, Fair, HSG D
12,066
55
Woods, Good, HSG B
0
70
Woods, Good, HSG C
28,227
77
Woods, Good, HSG D
111,601
83
Weighted Average
74,662
66.90% Pervious Area
36,939
33.10% Impervious 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"
1
80
0.0650
1.78
Shallow Concentrated Flow, BC
Short Grass Pasture   Kv= 7.0 fps
1
65
0.0550
1.17
Shallow Concentrated Flow, CD
Woodland   Kv= 5.0 fps
10
295
Total

NOAA 24-hr D  2-Year Rainfall=3.44"
EX WS_Conservation Submission
  Printed  4/28/2025
Prepared by Langan Engineering
Page 9
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Subcatchment EXWS-3: 
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
2-Year Rainfall=3.44"
Runoff Area=111,601 sf
Runoff Volume=16,816 CF
Runoff Depth=1.81"
Flow Length=295'
Tc=10 min
CN=83
4.62 cfs

NOAA 24-hr D  2-Year Rainfall=3.44"
EX WS_Conservation Submission
  Printed  4/28/2025
Prepared by Langan Engineering
Page 10
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Summary for Link Site: 
Inflow Area =
16.30 ac, 22.88% Impervious,  Inflow Depth = 1.84"    for  2-Year event
Inflow
=
24.88 cfs @ 12.21 hrs,  Volume= 108,999 CF
Primary
=
24.88 cfs @ 12.21 hrs,  Volume= 108,999 CF,  Atten= 0%,  Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs
Link Site: 
Inflow
Primary
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)
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Inflow Area=16.30 ac
24.88 cfs
24.88 cfs

NOAA 24-hr D  10-Year Rainfall=5.14"
EX WS_Conservation Submission
  Printed  4/28/2025
Prepared by Langan Engineering
Page 11
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Time span=0.00-48.00 hrs, dt=0.05 hrs, 961 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=357,584 sf   8.39% Impervious   Runoff Depth=3.11"
Subcatchment EXWS-1: 
   Flow Length=560'   Tc=18 min   CN=81   Runoff=20.01 cfs  92,655 CF
Runoff Area=240,801 sf   39.65% Impervious   Runoff Depth=3.70"
Subcatchment EXWS-2: 
   Flow Length=687'   Tc=12 min   CN=87   Runoff=18.68 cfs  74,233 CF
Runoff Area=111,601 sf   33.10% Impervious   Runoff Depth=3.30"
Subcatchment EXWS-3: 
   Flow Length=295'   Tc=10 min   CN=83   Runoff=8.34 cfs  30,700 CF
   Inflow=44.64 cfs  197,588 CF
Link Site: 
   Primary=44.64 cfs  197,588 CF
Total Runoff Area = 16.30 ac   Runoff Volume = 197,588 CF   Average Runoff Depth = 3.34"
77.12% Pervious = 12.57 ac     22.88% Impervious = 3.73 ac

NOAA 24-hr D  10-Year Rainfall=5.14"
EX WS_Conservation Submission
  Printed  4/28/2025
Prepared by Langan Engineering
Page 12
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Summary for Subcatchment EXWS-1: 
Runoff
=
20.01 cfs @ 12.27 hrs,  Volume=
92,655 CF,  Depth= 3.11"
     Routed to Link Site : 
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs
NOAA 24-hr D  10-Year Rainfall=5.14"
Area (sf)
CN
Description
*
30,013
98
Impervious
0
69
50-75% Grass cover, Fair, HSG B
76,186
79
50-75% Grass cover, Fair, HSG C
173,587
84
50-75% Grass cover, Fair, HSG D
784
55
Woods, Good, HSG B
62,291
70
Woods, Good, HSG C
14,723
77
Woods, Good, HSG D
357,584
81
Weighted Average
327,571
91.61% Pervious Area
30,013
8.39% Impervious Area
Tc
Length
Slope
Velocity
Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
5
28
0.0666
0.10
Sheet Flow, AB
Woods: Light underbrush   n= 0.400   P2= 3.44"
0
12
0.0666
1.51
Sheet Flow, BC
Smooth surfaces   n= 0.011   P2= 3.44"
5
90
0.0667
0.28
Sheet Flow, CD
Grass: Short   n= 0.150   P2= 3.44"
3
20
0.0200
0.13
Sheet Flow, DE
Grass: Short   n= 0.150   P2= 3.44"
3
180
0.0150
0.86
Shallow Concentrated Flow, EF
Short Grass Pasture   Kv= 7.0 fps
2
230
0.0667
1.81
Shallow Concentrated Flow, FG
Short Grass Pasture   Kv= 7.0 fps
18
560
Total

NOAA 24-hr D  10-Year Rainfall=5.14"
EX WS_Conservation Submission
  Printed  4/28/2025
Prepared by Langan Engineering
Page 13
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)
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
NOAA 24-hr D
10-Year Rainfall=5.14"
Runoff Area=357,584 sf
Runoff Volume=92,655 CF
Runoff Depth=3.11"
Flow Length=560'
Tc=18 min
CN=81
20.01 cfs

NOAA 24-hr D  10-Year Rainfall=5.14"
EX WS_Conservation Submission
  Printed  4/28/2025
Prepared by Langan Engineering
Page 14
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Summary for Subcatchment EXWS-2: 
Runoff
=
18.68 cfs @ 12.19 hrs,  Volume=
74,233 CF,  Depth= 3.70"
     Routed to Link Site : 
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs
NOAA 24-hr D  10-Year Rainfall=5.14"
Area (sf)
CN
Description
*
95,484
98
Impervious
3,180
69
50-75% Grass cover, Fair, HSG B
68,825
79
50-75% Grass cover, Fair, HSG C
56,323
84
50-75% Grass cover, Fair, HSG D
0
55
Woods, Good, HSG B
16,771
70
Woods, Good, HSG C
218
77
Woods, Good, HSG D
240,801
87
Weighted Average
145,317
60.35% Pervious Area
95,484
39.65% Impervious Area
Tc
Length
Slope
Velocity
Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
0
24
0.0120
0.87
Sheet Flow, AB
Smooth surfaces   n= 0.011   P2= 3.44"
1
126
0.0833
2.64
Sheet Flow, BC
Smooth surfaces   n= 0.011   P2= 3.44"
2
145
0.0300
1.21
Shallow Concentrated Flow, CD
Short Grass Pasture   Kv= 7.0 fps
9
392
0.0120
0.77
Shallow Concentrated Flow, DE
Short Grass Pasture   Kv= 7.0 fps
12
687
Total

NOAA 24-hr D  10-Year Rainfall=5.14"
EX WS_Conservation Submission
  Printed  4/28/2025
Prepared by Langan Engineering
Page 15
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Subcatchment EXWS-2: 
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)
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
NOAA 24-hr D
10-Year Rainfall=5.14"
Runoff Area=240,801 sf
Runoff Volume=74,233 CF
Runoff Depth=3.70"
Flow Length=687'
Tc=12 min
CN=87
18.68 cfs

NOAA 24-hr D  10-Year Rainfall=5.14"
EX WS_Conservation Submission
  Printed  4/28/2025
Prepared by Langan Engineering
Page 16
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Summary for Subcatchment EXWS-3: 
Runoff
=
8.34 cfs @ 12.17 hrs,  Volume=
30,700 CF,  Depth= 3.30"
     Routed to Link Site : 
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs
NOAA 24-hr D  10-Year Rainfall=5.14"
Area (sf)
CN
Description
*
36,939
98
Impervious
2,483
69
50-75% Grass cover, Fair, HSG B
0
79
50-75% Grass cover, Fair, HSG C
31,886
84
50-75% Grass cover, Fair, HSG D
12,066
55
Woods, Good, HSG B
0
70
Woods, Good, HSG C
28,227
77
Woods, Good, HSG D
111,601
83
Weighted Average
74,662
66.90% Pervious Area
36,939
33.10% Impervious 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"
1
80
0.0650
1.78
Shallow Concentrated Flow, BC
Short Grass Pasture   Kv= 7.0 fps
1
65
0.0550
1.17
Shallow Concentrated Flow, CD
Woodland   Kv= 5.0 fps
10
295
Total

NOAA 24-hr D  10-Year Rainfall=5.14"
EX WS_Conservation Submission
  Printed  4/28/2025
Prepared by Langan Engineering
Page 17
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Subcatchment EXWS-3: 
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)
9
8
7
6
5
4
3
2
1
0
NOAA 24-hr D
10-Year Rainfall=5.14"
Runoff Area=111,601 sf
Runoff Volume=30,700 CF
Runoff Depth=3.30"
Flow Length=295'
Tc=10 min
CN=83
8.34 cfs

NOAA 24-hr D  10-Year Rainfall=5.14"
EX WS_Conservation Submission
  Printed  4/28/2025
Prepared by Langan Engineering
Page 18
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Summary for Link Site: 
Inflow Area =
16.30 ac, 22.88% Impervious,  Inflow Depth = 3.34"    for  10-Year event
Inflow
=
44.64 cfs @ 12.21 hrs,  Volume= 197,588 CF
Primary
=
44.64 cfs @ 12.21 hrs,  Volume= 197,588 CF,  Atten= 0%,  Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs
Link Site: 
Inflow
Primary
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)
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
Inflow Area=16.30 ac
44.64 cfs
44.64 cfs

NOAA 24-hr D  25-Year Rainfall=6.21"
EX WS_Conservation Submission
  Printed  4/28/2025
Prepared by Langan Engineering
Page 19
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Time span=0.00-48.00 hrs, dt=0.05 hrs, 961 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=357,584 sf   8.39% Impervious   Runoff Depth=4.08"
Subcatchment EXWS-1: 
   Flow Length=560'   Tc=18 min   CN=81   Runoff=26.08 cfs  121,447 CF
Runoff Area=240,801 sf   39.65% Impervious   Runoff Depth=4.72"
Subcatchment EXWS-2: 
   Flow Length=687'   Tc=12 min   CN=87   Runoff=23.53 cfs  94,683 CF
Runoff Area=111,601 sf   33.10% Impervious   Runoff Depth=4.29"
Subcatchment EXWS-3: 
   Flow Length=295'   Tc=10 min   CN=83   Runoff=10.73 cfs  39,866 CF
   Inflow=57.30 cfs  255,997 CF
Link Site: 
   Primary=57.30 cfs  255,997 CF
Total Runoff Area = 16.30 ac   Runoff Volume = 255,997 CF   Average Runoff Depth = 4.33"
77.12% Pervious = 12.57 ac     22.88% Impervious = 3.73 ac

NOAA 24-hr D  25-Year Rainfall=6.21"
EX WS_Conservation Submission
  Printed  4/28/2025
Prepared by Langan Engineering
Page 20
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Summary for Subcatchment EXWS-1: 
Runoff
=
26.08 cfs @ 12.27 hrs,  Volume= 121,447 CF,  Depth= 4.08"
     Routed to Link Site : 
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs
NOAA 24-hr D  25-Year Rainfall=6.21"
Area (sf)
CN
Description
*
30,013
98
Impervious
0
69
50-75% Grass cover, Fair, HSG B
76,186
79
50-75% Grass cover, Fair, HSG C
173,587
84
50-75% Grass cover, Fair, HSG D
784
55
Woods, Good, HSG B
62,291
70
Woods, Good, HSG C
14,723
77
Woods, Good, HSG D
357,584
81
Weighted Average
327,571
91.61% Pervious Area
30,013
8.39% Impervious Area
Tc
Length
Slope
Velocity
Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
5
28
0.0666
0.10
Sheet Flow, AB
Woods: Light underbrush   n= 0.400   P2= 3.44"
0
12
0.0666
1.51
Sheet Flow, BC
Smooth surfaces   n= 0.011   P2= 3.44"
5
90
0.0667
0.28
Sheet Flow, CD
Grass: Short   n= 0.150   P2= 3.44"
3
20
0.0200
0.13
Sheet Flow, DE
Grass: Short   n= 0.150   P2= 3.44"
3
180
0.0150
0.86
Shallow Concentrated Flow, EF
Short Grass Pasture   Kv= 7.0 fps
2
230
0.0667
1.81
Shallow Concentrated Flow, FG
Short Grass Pasture   Kv= 7.0 fps
18
560
Total

NOAA 24-hr D  25-Year Rainfall=6.21"
EX WS_Conservation Submission
  Printed  4/28/2025
Prepared by Langan Engineering
Page 21
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)
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
NOAA 24-hr D
25-Year Rainfall=6.21"
Runoff Area=357,584 sf
Runoff Volume=121,447 CF
Runoff Depth=4.08"
Flow Length=560'
Tc=18 min
CN=81
26.08 cfs

NOAA 24-hr D  25-Year Rainfall=6.21"
EX WS_Conservation Submission
  Printed  4/28/2025
Prepared by Langan Engineering
Page 22
HydroCAD® 10.20-6a  s/n 08223  © 2024 HydroCAD Software Solutions LLC
Summary for Subcatchment EXWS-2: 
Runoff
=
23.53 cfs @ 12.19 hrs,  Volume=
94,683 CF,  Depth= 4.72"
     Routed to Link Site : 
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs
NOAA 24-hr D  25-Year Rainfall=6.21"
Area (sf)
CN
Description
*
95,484
98
Impervious
3,180
69
50-75% Grass cover, Fair, HSG B
68,825
79
50-75% Grass cover, Fair, HSG C
56,323
84
50-75% Grass cover, Fair, HSG D
0
55
Woods, Good, HSG B
16,771
70
Woods, Good, HSG C
218
77
Woods, Good, HSG D
240,801
87
Weighted Average
145,317
60.35% Pervious Area
95,484
39.65% Impervious Area
Tc
Length
Slope
Velocity
Capacity
Desc