Conservation Commission Regular Meeting Materials (linked)

WATERFORD APARTMENT COMMUNITY 
HARTFORD TURNPIKE  
 
Drainage Report 
 
Prepared for: 
Hendels Rte 85 Land LLC 
35 Great Neck Road 
Waterford, Connecticut 06385 
 
SLR #141.15901.00004 
 
June 3, 2021 
Revised September 20, 2021 
 

 
 
Drainage Report 
Waterford Apartment Community 
969 Hartford Turnpike 
Waterford, Connecticut 
June 3, 2021, Revised 9/20/2021 
141.15901.00004 
 
This Drainage Report has been prepared in support of a proposed multifamily residential project to be 
constructed at 969 Hartford Turnpike in the town of Waterford, Connecticut. The site will gain access via 
a new entrance drive off Hartford Turnpike directly across Cross Road. A proposed looped internal drive 
will provide access to the seven new apartment buildings. Surface parking spaces will be provided 
throughout the new community along with seven garage parking structures. The new development will 
also include a clubhouse, a community pool, a playscape area, and a recycling building. The overall 
property is currently an undeveloped, heavily wooded tract of land.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 1 – #969 Parcel 

 
 
Waterford Apartment Community 
3 
June 3, 2021 
Drainage Report  
Table 1 – Stormwater Data 
 
Parcel Size Total 
35.54 acres 
Existing Impervious Area (Project Area) 
0.0 acres 
Proposed Impervious Area (Project Area) 
8.76 acres 
Soil Types (Hydrologic Soil Group) 
"B" and "D" 
Existing Land Use 
Woods and some open space 
Proposed Land Use 
Woods, open space, concrete sidewalks, 
bituminous pavement, paved patios, and 
building 
Design Storm for Stormwater Management 
No increases in peak rates of runoff for the 2-, 
10-, 25-, 50-, and 100-year storms; first-flush 
runoff retention (CTDEEP WQV) 
Water Quality Measures 
Disconnected impervious, water quality basins, 
catch basins with sumps, hydrodynamic 
separators, riprap energy dissipators, sediment 
forebays, and retention storage 
Design Storm for Storm Drainage 
10-year storm 
Federal Emergency Management Agency  
Special Flood Hazard Areas 
Area of Minimal Flood Hazard (Zone X) 
Connecticut Department of Energy & 
Environmental Protection Aquifer Protection 
Areas 
Not applicable 
 
STORMWATER MANAGEMENT APPROACH 
 
The stormwater management system for this site has been designed utilizing Best Management Practices 
(BMPs) to provide water quality management while attenuating the proposed peak-flow rates from the 
development. The design goal is to provide water quality treatment in accordance with the Connecticut 
Department of Energy & Environmental Protection (CTDEEP) requirements for Water Quality Volume 
(WQV) and prevent increases in the predevelopment runoff rates from the project site. Existing drainage 
patterns will be maintained to the maximum extent practicable, and a new stormwater treatment train is 
proposed with vegetated water quality basins, catch basins with deep sumps, hydrodynamic separators, 
riprap energy dissipators, sediment forebays, and retention storage within the stormwater management 
basins.  
 
The proposed basins were properly sized to prevent increases in the predevelopment peak runoff rates 
to the discharge locations from the site. The basins are designated on the site plans as Basin 110, 120, 
130, and 140. Basins 110 and 120 are designed as Micropool Extended Detention Ponds per section 11 of 
the Stormwater Quality Manual.  The design is intended to incorporate permanent pool depths varying 
for each basin.  The permanent pools will help reduce thermal impacts and will utilize 100% of the required 
WQV.  The basin slopes in the permanent pool will be seeded with New England Wet Mix, with the 
remainder of the sides seeded with New England Erosion Control Seed Mix for moist sites.  In addition, 
the basin is noted to be inspected during construction to verify soil moisture conditions and additional 

 
 
Waterford Apartment Community 
4 
June 3, 2021 
Drainage Report  
plantings specified for the permanent pools according to Hydrologic Zone 1 in Table A-1 of the Stormwater 
Quality Manual.  Trees are proposed where appropriate for shading of the basins to allow for additional 
temperature mitigation.  Basin 130 is best categorized as a pocket pond and will be planted similarly to 
Basins 110 and 120.  Basin 140 was designed as a series of concrete underground chambers where flows 
will be controlled by a standard manhole structure that will be fitted with a concrete weir wall. The 
ultimate discharge from the basins will be directed toward the wetland areas located on the southern 
portion of the site. 
 
The computer program entitled Hydraflow Storm Sewers Extension for AutoCAD® Civil 3D® 2019 
by Autodesk, Inc., Version 2018.3, was used for designing the proposed storm drainage collection system. 
Storm drainage computations performed include pipe capacity, hydraulic grade line calculations, and 
gutter flow computations. The contributing watershed to each individual catch basin inlet was delineated 
to determine the drainage area and land coverage. These values were used to determine the stormwater 
runoff to each inlet using the Rational Method. The rainfall intensities for the site were obtained from the 
National Oceanic and Atmospheric Administration (NOAA) Atlas 14, Volume 10, Precipitation Frequency 
Data Server (PFDS). The proposed storm drainage system is designed to provide adequate capacity to 
convey the 10-year storm event. The outlet pipes from the stormwater basins were adequately sized to 
convey the 100-year discharge from the basins. 
 
WATER QUALITY MANAGEMENT 
 
Stormwater runoff from the proposed development will be collected by a subsurface pipe and catch basin 
drainage system. The proposed drainage system will include catch basins with 2-foot sumps that will trap 
sediments. Specific catch basins will be fitted with 4-foot sumps and hoods to increase their ability trap 
sediment and debris.  
 
Roof runoff from the proposed apartment buildings has been disconnected from the proposed storm 
drainage by directing the discharge from the proposed roof leaders into shallow water quality basins. 
These basins were sized to retain the runoff from the first 1 inch of rainfall over the rooftops, and any 
overflow from the water quality basins will drain into the storm drainage system.  
 
Hydrodynamic separators, such as CDS® devices manufactured by Contech Engineered Solutions, will be 
installed in the proposed storm drainage system prior to discharging stormwater runoff from the paved 
roads into Proposed Basins 120, 130, and 140. These units will further remove suspended solids before 
discharging downgradient, which will in turn remove other pollutants that tend to attach to suspended 
solids and effectively remove other debris and floatables that may be present in stormwater runoff. The 
hydrodynamic separators have been designed to meet criteria recommended by the CTDEEP 2004 
Stormwater Quality Manual. The devices were designed based on the determined Water Quality Flow 
(WQF), which is the peak-flow rate associated with the WQV and sized based on the manufacturer's 
specifications. The direct road discharge into Basin 110 will be via only two catch basins; therefore, a 
hydrodynamic separator will not be installed at this system. The two catch basins will be fitted with four 
sumps and hoods. 
 
Sediment forebays are proposed around the proposed drainage pipes that daylight into the stormwater 
management basins, which will improve water quality by trapping floatables and filtering coarse sediment 
and other pollutants. The forebay will be constructed using a riprap filter berm. Riprap splash pads and 
scour holes will dissipate the potential erosive velocity of stormwater entering the basins as well as trap 

 
 
Waterford Apartment Community 
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June 3, 2021 
Drainage Report  
sediment. The sediment forebays will contain the deposited sediment within a small area of the basin and 
will allow for maintenance accessibility. 
 
The bottom of the stormwater basins will retain stormwater runoff, thus creating a water quality feature 
within it. This serves several purposes, including stormwater renovation and first-flush retention. The 
vegetation will provide pollutant removal by filtering stormwater runoff and utilizing excess nutrients that 
may be present in the stormwater. The CTDEEP 2004 Stormwater Quality Manual (Chapter 7) 
recommends methods for sizing stormwater treatment measures with WQV computations. The WQV 
addresses the initial stormwater runoff, also commonly referred to as the "first-flush" runoff. The WQV 
provides adequate volume to store the runoff associated with the first 1 inch of rainfall, which tends to 
contain the highest concentration of potential pollutants. In addition, a simple method for estimating 
pollutant export from urban development sites has been performed to determine the pollutant removal 
effectiveness of the proposed stormwater treatment train. The results demonstrate that the proposed 
system will achieve 87 percent Total Suspended Solids (TSS) removal and considerable reductions in the 
total proposed pollutant loading for nutrients and metals. Supporting calculations have been included in 
the Appendix of this report.  
 
HYDROLOGIC ANALYSIS 
 
A hydrologic analysis was conducted to analyze the predevelopment and post-development peak-flow 
rates from the site. Three analysis points consisting of four existing subwatersheds were chosen based on 
the fact that each area receives stormwater runoff from a portion of the project. Analysis Point A 
represents the majority of the site, which contributes stormwater runoff to the wetland areas located on 
the southern portion of the property. This analysis point consists of two subwatersheds under existing 
conditions, one of which drains to an existing low area located in the northern portion of the site (WS 11). 
This low area overflows to the watershed designated as Watershed 10 on the existing conditions 
watershed map, which eventually drains to the wetland areas. Analysis Point B analyzes the portion of the 
site that drains to the existing drainage system in Hartford Turnpike. Analysis Point C analyzes the portion 
of the site that drains overland toward the northwestern property boundary. The total watershed area 
delineated is approximately 35.3 acres under both existing and proposed conditions.  
 
The method of predicting the surface water runoff rates utilized in this analysis was a computer program 
entitled Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2019 by Autodesk, Inc., Version 2020. 
The Hydrographs program is a computer model that utilizes the methodologies set forth in the 
Technical Release No. 55 (TR-55) manual and Technical Release No. 20 (TR-20) computer model, originally 
developed by the United States Department of Agriculture – Natural Resources Conservation Service 
(USDA-NRCS). The Hydrographs computer modeling program is primarily used for conducting hydrology 
studies such as this one. 
 
The Hydrographs computer program forecasts the rate of surface water runoff based upon several factors. 
The input data includes information on land use, hydrologic soil type, vegetation, contributing watershed 
area, time of concentration, rainfall data, storage volumes, exfiltration rates, and the hydraulic capacity 
of structures. The computer model predicts the amount of runoff as a function of time, with the ability to 
include the attenuation effect due to dams, lakes, large wetlands, floodplains, and stormwater 
management basins. The input data for rainfalls with statistical recurrence frequencies of 2, 10, 25, 50, 
and 100 years was obtained from the NOAA Atlas 14, Volume 10 database. The corresponding rainfall 
totals are listed below. 

 
 
Waterford Apartment Community 
6 
June 3, 2021 
Drainage Report  
 
Storm Frequency 
Rainfall (inches) 
2-year 
3.45 
10-year 
5.13 
25-year 
6.18 
50-year 
6.99 
100-year 
7.80 
 
Land use for the site under existing and proposed conditions was determined from field survey, town 
topographic maps, and aerial photogrammetry. Land use types used in the analysis included woods, 
grassed or open space, gravel, building, and impervious (paved) cover. Soil types in the watershed were 
determined from the CTDEEP Geographic Information System (GIS) database of the USDA-NRCS soil 
survey for New London County, Connecticut. For the analysis, the site was determined to contain 
hydrologic soil types "B" and "D" as classified by USDA-NRCS. The composite runoff Curve Number (CN) 
for each subwatershed was calculated based on the different land use and soil types. The time of 
concentration (Tc) was estimated for each subwatershed using the TR-55 methodology and was computed 
by summing all travel times through the watershed as sheet flow, shallow concentrated flow, and channel 
flow.  
 
The proposed underground chamber system was designed to allow some of the stormwater runoff to 
infiltrate into the underlying soils. Results from subsurface soil testing indicated that the site has little 
opportunity to infiltrate stormwater due to high groundwater. In the area of the proposed underground 
detention system, test pits revealed a shallow layer of sand and loam material that sits above the observed 
high groundwater level. The bottom elevation of the underground chambers was then set slightly 
embedded into the sandy layer, and an open-bottom concept will allow some of the water to infiltrate.  
 
The soil testing consisted of ten test pits where permeability samples were taken and failing head 
permeability tests were run on each sample. The exfiltration rate used in the design of the underground 
chamber system was obtained by averaging the results and reducing the average by 50%, thus providing 
a safety factor of 2, which is recommended by the CTDEEP Stormwater Quality Manual. The test pit logs 
and permeability testing results are included in the Appendix of this report. 
 
The existing conditions were modeled with the Hydrographs program to determine the peak-flow rates 
for the various storm events at each analysis point. A revised model was developed incorporating the 
proposed site conditions and the stormwater management basins. The flows obtained with the revised 
model were then compared to the results of the existing conditions model. Peak-flow rates from the 
project site were controlled by the storage volume provided within the stormwater basins and the 
hydraulic capacity of the outlet control structures. The surface basins have been designed to provide a 
minimum of 1 foot of freeboard to the top of the embankment during the 100-year storm event, and the 
underground chambers were designed such that during the 100-year storm event, the water surface 
elevation would not exceed the top of the concrete chambers. The following peak rates of runoff were 
obtained from the Hydrographs hydrology results: 
 
 

 
 
Waterford Apartment Community 
7 
June 3, 2021 
Drainage Report  
Analysis Point A – Southern Wetlands 
 
Peak Runoff Rate (cubic feet per second) 
Storm Frequency (years) 
2 
10 
25 
50 
100 
Existing Conditions 
4.4 
16.8 
29.8 
40.1 
50.8 
Proposed Conditions 
4.4 
13.0 
19.6 
27.1 
50.2 
 
*Top Elevation of Basin = 124.0 feet 
 
*Top Elevation of Basin = 150.0 feet 
 
*Top Elevation of Basin = 165.0 feet 
 
*Top Elevation of Concrete Chambers = 171.0 feet 
 
Analysis Point B – Hartford Turnpike Drainage System 
 
Peak Runoff Rate (cubic feet per second) 
Storm Frequency (years) 
2 
10 
25 
50 
100 
Existing Conditions 
3.8 
9.6 
13.8 
17.2 
20.7 
Proposed Conditions 
3.6 
8.6 
12.1 
14.9 
17.9 
 
Detention Basin 110* 
 
Water Surface Elevation (feet) 
Storm Frequency (years) 
2 
10 
25 
50 
100 
Proposed Conditions 
119.5 
121.5 
122.2 
122.7 
122.9 
Detention Basin 120* 
 
Water Surface Elevation (feet) 
Storm Frequency (years) 
2 
10 
25 
50 
100 
Proposed Conditions 
145.3 
147.3 
148.3 
148.7 
148.9 
Detention Basin 130* 
 
Water Surface Elevation (feet) 
Storm Frequency (years) 
2 
10 
25 
50 
100 
Proposed Conditions 
163.5 
163.7 
163.8 
163.9 
164.0 
Underground Detention 140* 
 
Water Surface Elevation (feet) 
Storm Frequency (years) 
2 
10 
25 
50 
100 
Proposed Conditions 
167.5 
168.7 
169.5 
170.2 
170.6 

 
 
Waterford Apartment Community 
8 
June 3, 2021 
Drainage Report  
Analysis Point C – Northwestern Property Boundary 
 
Peak Runoff Rate (cubic feet per second) 
Storm Frequency (years) 
2 
10 
25 
50 
100 
Existing Conditions 
0.5 
2.5 
4.3 
5.9 
7.5 
Proposed Conditions 
0.4 
1.9 
3.0 
4.0 
5.1 
 
 
CONCLUSION 
 
The results of the hydrologic analysis demonstrate that there will be no increases in peak-flow rates from 
the proposed development. This was achieved for the storm events modeled through a planned 
stormwater management system with detention provided in the proposed stormwater management 
basins.  
 
The proposed development will also introduce a new stormwater treatment train consisting of several 
water quality measures such as vegetated water quality basins, catch basins with deep sumps, 
hydrodynamic separators, riprap energy dissipators, sediment forebays, and retention storage within the 
proposed stormwater management basins. Roof runoff from the proposed apartment buildings has been 
disconnected by directing the discharge from the proposed roof leaders into shallow water quality basins, 
which were sized to retain the runoff from the first 1 inch of rainfall over the rooftops. 
 
The proprietary water quality units (hydrodynamic separators) selected for the project were sized based 
on the contributing WQF, which is the peak-flow rate associated with the WQV. Furthermore, the CTDEEP 
WQV has been provided within the retention storage area along the bottom of the proposed stormwater 
management basins.  
 
All supporting documentation and stormwater-related computations are attached to this report along 
with the Hydraflow Hydrographs model results for stormwater management and Hydraflow Storm Sewers 
model results for the proposed storm drainage system. Illustrative watershed maps for both existing and 
proposed conditions are also attached to this report.  
 
Attachments 
 
Attachment A – United States Geological Survey Location Map 
Attachment B – Federal Emergency Management Agency Flood Insurance Rate Map 
Attachment C – Natural Resources Conservation Service Hydrologic Soil Group Map 
Attachment D – Soil Testing 
Attachment E – Storm Drainage Computations 
Attachment F – Water Quality Computations 
Attachment G – Hydrologic Analysis – Input Computations 
Attachment H – Hydrologic Analysis – Computer Model Results 
Attachment I – Watershed Maps 
 
15901.00004.j221.rpt.docx 
 
 

 
 
 
 
APPENDIX A 
 
UNITED STATES GEOLOGICAL SURVEY  
LOCATION MAP 
Drainage Report 
Waterford Apartment Community 
969 Hartford Turnpike 
Waterford, Connecticut 
 
June 3, 2021 
Revised September 20, 2021 
 
 
 
 
 

S
W
N
E
0'
1,200'
2,400'
0
1/2"
1"
LOC
DRAWING NAME:
USGS QUADRANGLE MAP, QUAD NO. 86
WATERFORD, CONNECTICUT
WATERFORD APARTMENT COMMUNITY
969 HARTFORD TURNPIKE
PROJ. NO. 5901-04
SCALE
1"=2,400'
DATE
JUNE 3, 2021
CHECKED
DRAWN
DESIGNED
---
MCB
---
PROJECT PHASE:
REV: ---
Copyright SLR Consulting, Inc - 2021
SITE LOCATION
99 REALTY DRIVE
CHESHIRE, CT 06410
203.271.1773
SLRCONSULTING.COM

 
 
 
 
 
ATTACHMENT B 
 
FEDERAL EMERGENCY  
MANAGEMENT AGENCY  
FLOOD INSURANCE RATE MAP 
Drainage Report 
Waterford Apartment Community 
969 Hartford Turnpike 
Waterford, Connecticut 
 
June 3, 2021 
Revised September 20, 2021 
 
 
 
 
 

National Flood Hazard Layer FIRM
ette
0
500
1,000
1,500
2,000
250
Feet
Ü
SEE FIS REPORT FOR DETAILED LEGEND AND INDEX M
AP FOR FIRM
 PANEL LAYOUT
SPECIAL FLOOD
HAZARD AREAS
W
ithout Base Flood Elevation (BFE)
Zone A, V, A99
W
ith BFE or DepthZone AE, AO, AH, VE, AR
Regulatory Floodway
0.2%
 Annual Chance Flood Hazard, Areas
of 1%
 annual chance flood with average
depth less than one foot or with drainage
areas of less than one square m
ileZone X
Future Conditions 1%
 Annual
Chance Flood HazardZone X
Area with Reduced Flood Risk due to
Levee. See Notes.Zone X
Area with Flood Risk due to LeveeZone D
NO SCREENArea of M
inim
al Flood Hazard Zone X
Area of Undeterm
ined Flood HazardZone D
Channel, Culvert, or Storm
 Sewer
Levee, Dike, or Floodwall
Cross Sections with 1%
 Annual Chance
17.5 W
ater Surface Elevation
Coastal Transect
Coastal Transect Baseline
Profile Baseline
Hydrographic Feature
Base Flood Elevation Line (BFE)
Effective LOM
Rs
Lim
it of Study
Jurisdiction Boundary
Digital Data Available
No Digital Data Available
Unm
apped
This m
ap com
plies with FEM
A's standards for the use of
digital flood m
aps if it is not void as described below.
The basem
ap shown com
plies with FEM
A's basem
ap
accuracy standards
The flood hazard inform
ation is derived directly from
 the
authoritative NFHL web services provided by FEM
A. This m
ap
was exported on 5/24/2021 at 12:57 PM
  and does not
reflect changes or am
endm
ents subsequent to this date and
tim
e. The NFHL and effective inform
ation m
ay change or
becom
e superseded by new data over tim
e.
This m
ap im
age is void if the one or m
ore of the following m
ap
elem
ents do not appear: basem
ap im
agery, flood zone labels,
legend, scale bar, m
ap creation date, com
m
unity identifiers,
FIRM
 panel num
ber, and FIRM
 effective date. M
ap im
ages for
unm
apped and unm
odernized areas cannot be used for
regulatory purposes.
Legend
OTHER AREAS OF
FLOOD HAZARD
OTHER AREAS
GENERAL
STRUCTURES
OTHER
FEATURES
M
AP PANELS
8
B
20.2
The pin displayed on the m
ap is an approxim
ate
point selected by the user and does not represent
an authoritative property location.
1:6,000
72°9'44"W
 41°23'20"N
72°9'7"W
 41°22'53"N
Basem
ap: USGS National M
ap: Orthoim
agery: Data refreshed October, 2020

 
 
 
 
 
ATTACHMENT C 
 
NATURAL RESOURCES  
CONSERVATION SERVICE  
HYDROLOGIC SOIL GROUP MAP 
Drainage Report 
Waterford Apartment Community 
969 Hartford Turnpike 
Waterford, Connecticut 
 
June 3, 2021 
Revised September 20, 2021 
 
 
 
 

Hydrologic Soil Group—State of Connecticut
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
6/3/2021
Page 1 of 5
4584900
4585000
4585100
4585200
4585300
4585400
4585500
4585600
4585700
4585800
4585900
4586000
4586100
4585000
4585100
4585200
4585300
4585400
4585500
4585600
4585700
4585800
4585900
4586000
4586100
737300
737400
737500
737600
737700
737800
737900
738000
738100
737300
737400
737500
737600
737700
737800
737900
738000
738100
738200
41°  23' 29'' N
72°  9' 44'' W
41°  23' 29'' N
72°  9' 4'' W
41°  22' 49'' N
72°  9' 44'' W
41°  22' 49'' N
72°  9' 4'' W
N
Map projection: Web Mercator   Corner coordinates: WGS84   Edge tics: UTM Zone 18N WGS84
0
250
500
1000
1500
Feet
0
50
100
200
300
Meters
Map Scale: 1:6,020 if printed on A portrait (8.5" x 11") sheet.
Soil Map may not be valid at this scale.

MAP LEGEND
MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Lines
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Points
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at 
1:12,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause 
misunderstanding of the detail of mapping and accuracy of soil 
line placement. The maps do not show the small areas of 
contrasting soils that could have been shown at a more detailed 
scale.
Please rely on the bar scale on each map sheet for map 
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: 
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator 
projection, which preserves direction and shape but distorts 
distance and area. A projection that preserves area, such as the 
Albers equal-area conic projection, should be used if more 
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as 
of the version date(s) listed below.
Soil Survey Area: State of Connecticut
Survey Area Data: Version 20, Jun 9, 2020
Soil map units are labeled (as space allows) for map scales 
1:50,000 or larger.
Date(s) aerial images were photographed: Mar 20, 2019—Mar 
27, 2019
The orthophoto or other base map on which the soil lines were 
compiled and digitized probably differs from the background 
imagery displayed on these maps. As a result, some minor 
shifting of map unit boundaries may be evident.
Hydrologic Soil Group—State of Connecticut
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
6/3/2021
Page 2 of 5

Hydrologic Soil Group
Map unit symbol
Map unit name
Rating
Acres in AOI
Percent of AOI
3
Ridgebury, Leicester, 
and Whitman soils, 0 
to 8 percent slopes, 
extremely stony
D
11.6
6.4%
12
Raypol silt loam
C/D
1.8
1.0%
13
Walpole sandy loam, 0 
to 3 percent slopes
B/D
3.3
1.8%
15
Scarboro muck, 0 to 3 
percent slopes
A/D
0.1
0.1%
18
Catden and Freetown 
soils, 0 to 2 percent 
slopes
B/D
5.8
3.2%
23A
Sudbury sandy loam, 0 
to 5 percent slopes
B
1.5
0.8%
29A
Agawam fine sandy 
loam, 0 to 3 percent 
slopes
B
2.4
1.3%
29B
Agawam fine sandy 
loam, 3 to 8 percent 
slopes
B
7.6
4.2%
34A
Merrimac fine sandy 
loam, 0 to 3 percent 
slopes
A
1.2
0.7%
51B
Sutton fine sandy loam, 
0 to 8 percent slopes, 
very stony
B/D
1.3
0.7%
52C
Sutton fine sandy loam, 
2 to 15 percent 
slopes, extremely 
stony
B/D
5.4
3.0%
61B
Canton and Charlton 
fine sandy loams, 0 to 
8 percent slopes, very 
stony
B
5.3
3.0%
62C
Canton and Charlton 
fine sandy loams, 3 to 
15 percent slopes, 
extremely stony
B
37.0
20.6%
62D
Canton and Charlton 
fine sandy loams, 15 
to 35 percent slopes, 
extremely stony
B
0.6
0.4%
73C
Charlton-Chatfield 
complex, 0 to 15 
percent slopes, very 
rocky
B
33.1
18.4%
Hydrologic Soil Group—State of Connecticut
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
6/3/2021
Page 3 of 5

Map unit symbol
Map unit name
Rating
Acres in AOI
Percent of AOI
73E
Charlton-Chatfield 
complex, 15 to 45 
percent slopes, very 
rocky
B
8.6
4.8%
75E
Hollis-Chatfield-Rock 
outcrop complex, 15 
to 45 percent slopes
D
7.2
4.0%
103
Rippowam fine sandy 
loam
B/D
1.8
1.0%
107
Limerick and Lim soils
B/D
15.3
8.5%
306
Udorthents-Urban land 
complex
B
24.1
13.4%
307
Urban land
D
0.4
0.2%
701A
Ninigret fine sandy 
loam, 0 to 3 percent 
slopes
C
1.4
0.8%
703A
Haven silt loam, 0 to 3 
percent slopes
B
3.1
1.7%
Totals for Area of Interest
180.0
100.0%
Hydrologic Soil Group—State of Connecticut
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
6/3/2021
Page 4 of 5

Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are 
assigned to one of four groups according to the rate of water infiltration when the 
soils are not protected by vegetation, are thoroughly wet, and receive 
precipitation from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and 
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when 
thoroughly wet. These consist mainly of deep, well drained to excessively 
drained sands or gravelly sands. These soils have a high rate of water 
transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These 
consist chiefly of moderately deep or deep, moderately well drained or well 
drained soils that have moderately fine texture to moderately coarse texture. 
These soils have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist 
chiefly of soils having a layer that impedes the downward movement of water or 
soils of moderately fine texture or fine texture. These soils have a slow rate of 
water transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when 
thoroughly wet. These consist chiefly of clays that have a high shrink-swell 
potential, soils that have a high water table, soils that have a claypan or clay 
layer at or near the surface, and soils that are shallow over nearly impervious 
material. These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is 
for drained areas and the second is for undrained areas. Only the soils that in 
their natural condition are in group D are assigned to dual classes.
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified 
Tie-break Rule: Higher
Hydrologic Soil Group—State of Connecticut
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
6/3/2021
Page 5 of 5

 
 
 
 
 
ATTACHMENT D 
 
SOIL TESTING 
Drainage Report 
Waterford Apartment Community 
969 Hartford Turnpike 
Waterford, Connecticut 
 
June 3, 2021 
Revised September 20, 2021 
 
 
 
 

MMI #5901-04
Falling Head Permeability Test
Summary
4/20/2018
Sample
K (in/hr)
K (ft/day)
TP 9 Depth 32"
3.56
7.12
TP 10 Depth 30"
1.33
2.66
TP 11 Depth 30"
1.59
3.19
TP 5 Depth 60"
1.06
2.13
TP 13 Depth 36"
1.48
2.97
TP 15 Depth 52"
4.24
8.47
TP 16A Depth 30"
23.72
47.44
TP 16B Depth 20"
13.25
26.50
TP 18 Depth 28"
10.00
20.00
TP 20 Depth 25"
1.22
2.43
Average Permeability = (3.56 + 1.33 + 1.59 + 1.06 + 1.48 + 4.24 + 1.22) / 7 = 2.06 in/hr 
 
2.06 in/hr * 50% = 1.03 in/hr 
 
*Note: off-range permeability results from Test Pits 16A, 16B, and 18 were not included in 
the calculations.
off-ranges

W:\Design\5901-04-DE\Data-Collection\Test Pits\Test Pit Log.xlsx
Test Pit No:    
1
Sheet   
1
of 20
MMI File No: 
5901-04
Ground Elev: 
Not recorded
Datum: 
N/A
Date:
Weather:  
60 deg F and sunny
Depth Below 
Grade (ft)
Excavation 
Effort
Boulder 
Qty/Class Remarks
Top Soil
Notes/Remarks:
4/13/2018
TEST PIT LOG
PROJECT
99 Realty Drive
Waterford Multifamily Development
Cheshire, CT 06410
MMI Rep.: Van Hopson
Strata Change (in) & 
Water Level
Subsurface Description
1
2
12
3
4
5
6
7
8
9
10
11
13
14
15
Water Symbols
Seeps at 24"
0-7
7-42
Orange Brown silty loam, some boulders with redox 
features throughout
Bottom of Excavation +/- 3.5'
= Groundwater
= Estimated Seasonal 
High Ground Water

W:\Design\5901-04-DE\Data-Collection\Test Pits\Test Pit Log.xlsx
Test Pit No:    
2
Sheet   
2
of 20
MMI File No: 
5901-04
Ground Elev: 
Not recorded
Datum: 
N/A
Date:
Weather:  
60 deg F and sunny
Depth Below 
Grade (ft)
Excavation 
Effort
Boulder 
Qty/Class Remarks
Top Soil
Gray Coarse sand and gravel, some cobbles
Notes/Remarks:
TEST PIT LOG
PROJECT
99 Realty Drive
Waterford Multifamily Development
Cheshire, CT 06410
MMI Rep.: Van Hopson
4/13/2018
Subsurface Description
1
0-6
2
3
4
5
6
7
Strata Change (in) & 
Water Level
8
9
10
11
12
13
14
15
Water Symbols
49-68
Bottom of Excavation +/- 6'
6-49
Orange Brown Silty sand, estimatede high ground water at 
47"
= Groundwater
= Estimated Seasonal 
High Ground Water

W:\Design\5901-04-DE\Data-Collection\Test Pits\Test Pit Log.xlsx
Test Pit No:    
3
Sheet   
3
of 20
MMI File No: 
5901-04
Ground Elev: 
Not recorded
Datum: 
N/A
Date:
Weather:  
60 deg F and sunny
Depth Below 
Grade (ft)
Excavation 
Effort
Boulder 
Qty/Class Remarks
Top Soil
Orange Brown Compact Silty sand w/ redox features
Gray Coarse sand and gravel, some cobbles
Notes/Remarks:
TEST PIT LOG
PROJECT
99 Realty Drive
Waterford Multifamily Development
Cheshire, CT 06410
MMI Rep.: Van Hopson
4/13/2018
Strata Change (in) & 
Water Level
Subsurface Description
1
2
3
12
4
5
6
7
8
9
10
11
13
14
15
Water Symbols
Permeability sample taken at 48"
40-84
Bottom of Excavation +/- 7'
12-40
0-12
= Groundwater
= Estimated Seasonal 
High Ground Water

W:\Design\5901-04-DE\Data-Collection\Test Pits\Test Pit Log.xlsx
Test Pit No:    
4
Sheet   
4
of 20
MMI File No: 
5901-04
Ground Elev: 
Not recorded
Datum: 
N/A
Date:
Weather:  
60 deg F and sunny
Depth Below 
Grade (ft)
Excavation 
Effort
Boulder 
Qty/Class Remarks
Top Soil
Silty Loam
Orange Brown sand, some gravel
Notes/Remarks:
TEST PIT LOG
PROJECT
99 Realty Drive
Waterford Multifamily Development
Cheshire, CT 06410
MMI Rep.: Van Hopson
4/13/2018
7
8
9
Strata Change (in) & 
Water Level
Subsurface Description
1
2
3
4
34-44
0-16
16-34
Water Symbols
Seeps at 39"
10
11
12
13
14
15
5
6
Bottom of Excavation +/- 4'
= Groundwater
= Estimated Seasonal 
High Ground Water

W:\Design\5901-04-DE\Data-Collection\Test Pits\Test Pit Log.xlsx
Test Pit No:    
5
Sheet   
5
of 20
MMI File No: 
5901-04
Ground Elev: 
Not recorded
Datum: 
N/A
Date:
Weather:  
60 deg F and sunny
Depth Below 
Grade (ft)
Excavation 
Effort
Boulder 
Qty/Class Remarks
Top Soil
Orange Brown fine sandy silt w/ redox features
Gray fine sand and gravel
Notes/Remarks:
TEST PIT LOG
PROJECT
99 Realty Drive
Waterford Multifamily Development
Cheshire, CT 06410
MMI Rep.: Van Hopson
4/13/2018
8
Strata Change (in) & 
Water Level
Subsurface Description
1
2
3
4
0-12
12-59
Bottom of Excavation +/- 7'
15
Water Symbols
Diggable rock-cannot stabilize sides for deeper excavation
Permeabilty sample at 60"
9
10
11
12
13
14
5
6
7
59-82
= Groundwater
= Estimated Seasonal 
High Ground Water

W:\Design\5901-04-DE\Data-Collection\Test Pits\Test Pit Log.xlsx
Test Pit No:    
6
Sheet   
6
of 20
MMI File No: 
5901-04
Ground Elev: 
Not recorded
Datum: 
N/A
Date:
Weather:  
Not recorded
Depth Below 
Grade (ft)
Excavation 
Effort
Boulder 
Qty/Class Remarks
Top Soil
Orange Brown Sandy Loam, Some silt
Brown Silt, some sand
Notes/Remarks:
4/11/2018
TEST PIT LOG
PROJECT
99 Realty Drive
Waterford Multifamily Development
Cheshire, CT 06410
MMI Rep.: Aron Schumacher
3
4
5
Strata Change (in) & 
Water Level
Subsurface Description
1
0-10
2
15
Water Symbols
6
Bottom of Excavation +/- 5'
7
8
9
10
10-27
27-61
Roots at 12"
Water at 60"
11
12
13
14
= Groundwater
= Estimated Seasonal 
High Ground Water

W:\Design\5901-04-DE\Data-Collection\Test Pits\Test Pit Log.xlsx
Test Pit No:    
7
Sheet   
7
of 20
MMI File No: 
5901-04
Ground Elev: 
Not recorded
Datum: 
N/A
Date:
Weather:  
Not recorded
Depth Below 
Grade (ft)
Excavation 
Effort
Boulder 
Qty/Class Remarks
Top Soil
Orange Brown Sandy Loam, Some silt
Light Brown Sandy Loam, Some silt, cobbles
Notes/Remarks:
4/11/2018
TEST PIT LOG
PROJECT
99 Realty Drive
Waterford Multifamily Development
Cheshire, CT 06410
MMI Rep.: Aron Schumacher
3
Strata Change (in) & 
Water Level
Subsurface Description
1
0-10
2
13
4
5
6
7
8
9
10
11
12
14
15
Water Symbols
Roots at 12"
Machine Refusal. Possible ledge at 59"
10-30
30-59
Bottom of Excavation +/- 5'
= Groundwater
= Estimated Seasonal 
High Ground Water

W:\Design\5901-04-DE\Data-Collection\Test Pits\Test Pit Log.xlsx
Test Pit No:    
8
Sheet   
8
of 20
MMI File No: 
5901-04
Ground Elev: 
Not recorded
Datum: 
N/A
Date:
Weather:  
Not recorded
Depth Below 
Grade (ft)
Excavation 
Effort
Boulder 
Qty/Class Remarks
Top Soil
Orange Brown Sandy Loam, Some silt
Gray Silt (mottling)
Notes/Remarks:
TEST PIT LOG
PROJECT
99 Realty Drive
Waterford Multifamily Development
Cheshire, CT 06410
MMI Rep.: Aron Schumacher
4/11/2018
Strata Change (in) & 
Water Level
Subsurface Description
1
0-8
2
8-37
3
13
4
37-71
5
6
7
8
9
10
11
12
14
15
Water Symbols
Roots at 24"
Machine Refusal. Possible ledge at 71"
Bottom of Excavation +/- 6'
= Groundwater
= Estimated Seasonal 
High Ground Water

W:\Design\5901-04-DE\Data-Collection\Test Pits\Test Pit Log.xlsx
Test Pit No:    
9
Sheet   
9
of 20
MMI File No: 
5901-04
Ground Elev: 
Not recorded
Datum: 
N/A
Date:
Weather:  
Not recorded
Depth Below 
Grade (ft)
Excavation 
Effort
Boulder 
Qty/Class Remarks
Top Soil
Orange Brown Sandy Loam, Some silt
Gray Silt (mottling)
Notes/Remarks:
TEST PIT LOG
99 Realty Drive
Cheshire, CT 06410
PROJECT
Waterford Multifamily Development
Strata Change (in) & 
Water Level
Subsurface Description
MMI Rep.: Aron Schumacher
14
15
8
9
10
11
12
13
4/11/2018
Roots at 16"
Machine Refusal. Possible ledge at 71"
Permeability sample taken at 32"
Bottom of Excavation +/- 6'
12-36
0-12
36-71
Water Symbols
1
2
3
4
5
6
7
= Groundwater
= Estimated Seasonal 
High Ground Water

W:\Design\5901-04-DE\Data-Collection\Test Pits\Test Pit Log.xlsx
Test Pit No:    
10
Sheet   
10
of 20
MMI File No: 
5901-04
Ground Elev: 
Not recorded
Datum: 
N/A
Date:
Weather:  
Not recorded
Depth Below 
Grade (ft)
Excavation 
Effort
Boulder 
Qty/Class Remarks
Top Soil
Orange Brown Sandy Loam, Some silt
Gray Sand, Some Silt
Notes/Remarks:
4/11/2018
TEST PIT LOG
PROJECT
99 Realty Drive
Waterford Multifamily Development
Cheshire, CT 06410
MMI Rep.: Aron Schumacher
4
5
Strata Change (in) & 
Water Level
Subsurface Description
1
0-12
2
12-32
3
15
Water Symbols
6
7
8
9
10
32-49
Bottom of Excavation +/- 4'
Roots at 12"
Machine Refusal. Possible ledge at 49"
Permeability sample taken at 30"
11
12
13
14
= Groundwater
= Estimated Seasonal 
High Ground Water

W:\Design\5901-04-DE\Data-Collection\Test Pits\Test Pit Log.xlsx
Test Pit No:    
11
Sheet   
11
of 20
MMI File No: 
5901-04
Ground Elev: 
Not recorded
Datum: 
N/A
Date:
Weather:  
Not recorded
Depth Below 
Grade (ft)
Excavation 
Effort
Boulder 
Qty/Class Remarks
Top Soil
Orange Brown Sandy Loam, Some silt
Gray Sand, Some Silt
Notes/Remarks:
4/11/2018
TEST PIT LOG
PROJECT
99 Realty Drive
Waterford Multifamily Development
Cheshire, CT 06410
MMI Rep.: Aron Schumacher
4
0-6
Strata Change (in) & 
Water Level
Subsurface Description
1
2
3
14
5
6
7
8
9
10
11
12
13
15
Water Symbols
Roots at 19"
Machine Refusal. Possible ledge at 62"
6-36
Bottom of Excavation +/- 6'
36-67
= Groundwater
= Estimated Seasonal 
High Ground Water

W:\Design\5901-04-DE\Data-Collection\Test Pits\Test Pit Log.xlsx
Test Pit No:    
12
Sheet   
12
of 20
MMI File No: 
5901-04
Ground Elev: 
Not recorded
Datum: 
N/A
Date:
Weather:  
60 deg F and sunny
Depth Below 
Grade (ft)
Excavation 
Effort
Boulder 
Qty/Class Remarks
Top Soil
Orange Brown fine sandy silt
Gray fine sand and gravel, some boulders
Notes/Remarks:
4/13/2018
TEST PIT LOG
PROJECT
99 Realty Drive
Waterford Multifamily Development
Cheshire, CT 06410
MMI Rep.: Van Hopson
4
Strata Change (in) & 
Water Level
Subsurface Description
1
2
3
12
5
6
7
Bottom of Excavation +/- 6'
8
9
10
11
13
14
15
Water Symbols
Refusal at 72". Possible Ledge
0-8
8-40
40-72
= Groundwater
= Estimated Seasonal 
High Ground Water

W:\Design\5901-04-DE\Data-Collection\Test Pits\Test Pit Log.xlsx
Test Pit No:    
13
Sheet   
13
of 20
MMI File No: 
5901-04
Ground Elev: 
Not recorded
Datum: 
N/A
Date:
Weather:  
60 deg F and sunny
Depth Below 
Grade (ft)
Excavation 
Effort
Boulder 
Qty/Class Remarks
Top Soil
Orange Brown fine sandy silt
Gray fine sand and gravel, some boulders
Notes/Remarks:
TEST PIT LOG
PROJECT
99 Realty Drive
Waterford Multifamily Development
Cheshire, CT 06410
MMI Rep.: Van Hopson
4/13/2018
9
Strata Change (in) & 
Water Level
Subsurface Description
1
0-6
2
3
4
5
6
7
8
11
12
13
14
15
6-26
26-48
Bottom of Excavation +/- 4'
Water Symbols
Ledge at 48"
Permeability sample staken at 36"
10
= Groundwater
= Estimated Seasonal 
High Ground Water

W:\Design\5901-04-DE\Data-Collection\Test Pits\Test Pit Log.xlsx
Test Pit No:    
14
Sheet   
14
of 20
MMI File No: 
5901-04
Ground Elev: 
Not recorded
Datum: 
N/A
Date:
Weather:  
60 deg F and sunny
Depth Below 
Grade (ft)
Excavation 
Effort
Boulder 
Qty/Class Remarks
Top Soil
Orange Brown fine sandy silt
Gray fine sand and gravel, some boulders
Notes/Remarks:
TEST PIT LOG
PROJECT
99 Realty Drive
Waterford Multifamily Development
Cheshire, CT 06410
MMI Rep.: Van Hopson
4/13/2018
Strata Change (in) & 
Water Level
Subsurface Description
1
0-12
2
12-44
3
4
13
5
6
7
8
9
10
11
12
14
15
Water Symbols
Refusal at 59". Possible Ledge
44-59
Bottom of Excavation +/- 5'
= Groundwater
= Estimated Seasonal 
High Ground Water

W:\Design\5901-04-DE\Data-Collection\Test Pits\Test Pit Log.xlsx
Test Pit No:    
15
Sheet   
15
of 20
MMI File No: 
5901-04
Ground Elev: 
Not recorded
Datum: 
N/A
Date:
Weather:  
60 deg F and sunny
Depth Below 
Grade (ft)
Excavation 
Effort
Boulder 
Qty/Class Remarks
Top Soil
Gray Brown fine sandy silt w/ redox features
Gray fine sand and gravel
Notes/Remarks:
TEST PIT LOG
PROJECT
99 Realty Drive
Waterford Multifamily Development
Cheshire, CT 06410
MMI Rep.: Van Hopson
4/13/2018
8
Strata Change (in) & 
Water Level
Subsurface Description
1
0-11
2
3
4
5
11-49
49-96
15
Water Symbols
Permeabilty sample at 52"
9
10
11
12
13
14
6
7
Bottom of Excavation +/- 8'
= Groundwater
= Estimated Seasonal 
High Ground Water

W:\Design\5901-04-DE\Data-Collection\Test Pits\Test Pit Log.xlsx
Test Pit No:    
16
Sheet   
16
of 20
MMI File No: 
5901-04
Ground Elev: 
Not recorded
Datum: 
N/A
Date:
Weather:  
Not recorded
Depth Below 
Grade (ft)
Excavation 
Effort
Boulder 
Qty/Class Remarks
Top Soil
Orange Brown Silty Loam, Some sand
Gray Silt (Mottling)
Notes/Remarks:
4/11/2018
TEST PIT LOG
PROJECT
99 Realty Drive
Waterford Multifamily Development
Cheshire, CT 06410
MMI Rep.: Aron Schumacher
3
4
5
Strata Change (in) & 
Water Level
Subsurface Description
1
0-10
2
15
Water Symbols
6
7
Bottom of Excavation +/- 7'
8
9
10
10-23
23-85
Roots at 18"
Permeability Sample 16A at 30"
Permeability Sample 16B at 20"
11
12
13
14
= Groundwater
= Estimated Seasonal 
High Ground Water

W:\Design\5901-04-DE\Data-Collection\Test Pits\Test Pit Log.xlsx
Test Pit No:    
17
Sheet   
17
of 20
MMI File No: 
5901-04
Ground Elev: 
Not recorded
Datum: 
N/A
Date:
Weather:  
60 deg F and sunny
Depth Below 
Grade (ft)
Excavation 
Effort
Boulder 
Qty/Class Remarks
Top Soil
Brown sandy silt
Notes/Remarks:
TEST PIT LOG
PROJECT
99 Realty Drive
Waterford Multifamily Development
Cheshire, CT 06410
MMI Rep.: Van Hopson
4/13/2018
Strata Change (in) & 
Water Level
Subsurface Description
1
0-6
2
3
4
5
Gray fine sand and gravel
12
13
14
15
6
7
8
9
6-45
45-78
Bottom of Excavation +/- 6.5'
Water Symbols
10
11
= Groundwater
= Estimated Seasonal 
High Ground Water

W:\Design\5901-04-DE\Data-Collection\Test Pits\Test Pit Log.xlsx
Test Pit No:    
18
Sheet   
18
of 20
MMI File No: 
5901-04
Ground Elev: 
Not recorded
Datum: 
N/A
Date:
Weather:  
60 deg F and sunny
Depth Below 
Grade (ft)
Excavation 
Effort
Boulder 
Qty/Class Remarks
Top Soil
Orange Brown sandy silt
Notes/Remarks:
4/13/2018
TEST PIT LOG
PROJECT
99 Realty Drive
Waterford Multifamily Development
Cheshire, CT 06410
MMI Rep.: Van Hopson
3
4
Strata Change (in) & 
Water Level
Subsurface Description
1
0-9
2
13
5
Bottom of Excavation +/- 4'
6
7
8
9
10
11
12
14
15
Water Symbols
Seeps at 39"
Permeabilty sample taken at 28"
9-24
24-50
Orange gray fine sand and gravel
= Groundwater
= Estimated Seasonal 
High Ground Water

W:\Design\5901-04-DE\Data-Collection\Test Pits\Test Pit Log.xlsx
Test Pit No:    
19
Sheet   
19
of 20
MMI File No: 
5901-04
Ground Elev: 
Not recorded
Datum: 
N/A
Date:
Weather:  
Not recorded
Depth Below 
Grade (ft)
Excavation 
Effort
Boulder 
Qty/Class Remarks
Top Soil
Orange Brown Silty Loam, Some Sand
Notes/Remarks:
TEST PIT LOG
PROJECT
99 Realty Drive
Waterford Multifamily Development
Cheshire, CT 06410
MMI Rep.: Aron Schumacher
4/11/2018
10
Strata Change (in) & 
Water Level
Subsurface Description
1
0-15
2
3
4
5
15-37
Bottom of Excavation +/- 3'
Roots at 15"
Refusal
11
12
13
14
15
Water Symbols
6
7
8
9
= Groundwater
= Estimated Seasonal 
High Ground Water

W:\Design\5901-04-DE\Data-Collection\Test Pits\Test Pit Log.xlsx
Test Pit No:    
20
Sheet   
20
of 20
MMI File No: 
5901-04
Ground Elev: 
Not recorded
Datum: 
N/A
Date:
Weather:  
Not recorded
Depth Below 
Grade (ft)
Excavation 
Effort
Boulder 
Qty/Class Remarks
Top Soil, Cobbles (12") pockets
Light Brown Silty Loam, Some sand
Gray Silt (Mottling)
Notes/Remarks:
TEST PIT LOG
PROJECT
99 Realty Drive
Waterford Multifamily Development
Cheshire, CT 06410
MMI Rep.: Aron Schumacher
4/11/2018
10
11
Strata Change (in) & 
Water Level
Subsurface Description
1
0-9
2
9-27
3
4
5
12
13
14
15
Water Symbols
Bottom of Excavation +/- 6'
27-73
Roots at 12"
Permeability Sample at 25"
6
7
8
9
= Groundwater
= Estimated Seasonal 
High Ground Water

 
 
 
 
 
ATTACHMENT E 
 
STORM DRAINAGE COMPUTATIONS 
Drainage Report 
Waterford Apartment Community 
969 Hartford Turnpike 
Waterford, Connecticut 
 
June 3, 2021 
Revised September 20, 2021 
 
 
 
 
 
 
 
 
 

Project: Waterford Apartment Community
By: 
JRH
Date:
5/28/21
Location: 949 Hartford Turnpike, Waterford, CT
Checked:
VEH
Date:
6/2/21
Impervious 
Area        
C=0.90      
(sf)
Grassed 
Area      
C=0.3     
(sf)
Wooded 
Area      
C=0.2     
(sf)
Total Area  
(sf)
Total Area 
(ac)
Weighted 
C
Tc to Inlet    
(min)
2,625
769
0
3,394
0.08
0.76
5.0
2,976
16,790
4,259
24,025
0.55
0.36
5.0
2,204
1,206
0
3,410
0.08
0.69
5.0
3,674
817
0
4,491
0.10
0.79
5.0
6,127
5,146
0
11,273
0.26
0.63
5.0
4,137
765
0
4,902
0.11
0.81
5.0
20,204
5,840
0
26,044
0.60
0.77
5.0
3,451
845
0
4,296
0.10
0.78
5.0
8,397
879
0
9,276
0.21
0.84
5.0
9,732
3,117
0
12,849
0.29
0.75
5.0
13,158
3,537
0
16,695
0.38
0.77
5.0
3,689
1,025
0
4,714
0.11
0.77
5.0
5,355
1,434
0
6,789
0.16
0.77
5.0
4,813
2,643
0
7,456
0.17
0.69
5.0
4,692
6,566
0
11,258
0.26
0.55
5.0
11,949
5,699
0
17,648
0.41
0.71
5.0
14,840
5,696
1,174
21,710
0.50
0.70
5.0
0
5,169
25,736
30,905
0.71
0.22
5.0
0
25,441
8,056
33,497
0.77
0.28
19.9
6,554
2,712
0
9,266
0.21
0.72
5.0
5,160
8,138
0
13,298
0.31
0.53
5.0
8,956
3,108
0
12,064
0.28
0.75
5.0
7,707
1,223
0
8,930
0.21
0.82
6.0
16,129
9,966
0
26,095
0.60
0.67
5.0
5,592
1,609
0
7,201
0.17
0.77
5.0
8,195
2,398
0
10,593
0.24
0.76
5.0
12,132
4,032
0
16,164
0.37
0.75
5.0
11,450
4,255
0
15,705
0.36
0.74
5.0
19,114
5,672
0
24,786
0.57
0.76
5.0
4,718
1,637
0
6,355
0.15
0.75
5.0
4,005
580
0
4,585
0.11
0.82
5.0
5,263
217
0
5,480
0.13
0.88
5.0
0
7,687
47,683
55,370
1.27
0.21
22.9
25,760
8,735
35
34,530
0.79
0.75
5.0
9,288
3,564
0
12,852
0.30
0.73
5.0
14,799
4,513
0
19,312
0.44
0.76
5.0
11,398
4,766
0
16,164
0.37
0.72
5.0
0
4,068
56,730
60,798
1.40
0.21
19.3
0
11,498
7,337
18,835
0.43
0.26
10.5
14,840
6,164
746
21,750
0.50
0.71
5.0
26,180
8,321
64
34,565
0.79
0.75
5.0
OCS 110
KNOWN Q 100 yr = 29.23 cfs
OVFW RG 2 
OVFW RG 5 
120-IN FROM WQB 5
130-IN FROM WQB 1
CCB 21
CCB 10.2
OCS 130
OVRW RG 4
YD 12.3
CCB 9.1
130-IN
140-IN FROM WQB 2
CCB 130.2
CLCB 37
CCB 36
CCB 6
CCB 35
 YD 17.2
CCB 35.1
CCB 32
CCB 130.1
YD 13.1
CCB 12.1
KNOWN Q 10 yr = 10.79 cfs Elev. = 147.34
KNOWN Q 10 yr = 11.57 cfs Elev. = 163.73
OCS 120
KNOWN Q 100 yr = 21.19 cfs Elev. = 163.95
KNOWN Q 100 yr = 39.40 cfs Elev. = 148.94
Rational Method Individual Basin Calculations
Basin Name
CCB 10.4
120-IN
CCB 9
CCB 10
CCB 11
KNOWN Q 10 yr = 0.71 cfs Elev. = 168.66
100-IN
CCB 2
CCB 3
140-IN
OVFW RG 1
CCB 36.1
CCB 12
CCB 13
YD 38.2
CCB 14
 YD 17.1
CLCB 17
CCB 23
CLCL 23.1
CLCB 38
CCB 33
CCB 34
UG 140
CCB 10.1
OCS RG 3
120-OUT
CCB 10.3
CCB 7
KNOWN Q 100 yr = 3.63 cfs Elev. = 170.61

                 Time of Concentration (Tc) or Travel Time (Tt) Worksheet
Project:
Multifamily Development
By: JRH
Date:
Location:
Hartford Turnpike-Waterford, CT
Checked:
Date:
Circle one:
Present
Developed
Watershed: YD 13.1
Circle one:
T c
Tt
 Subwatershed:   
Sheet flow (applicable to Tc only)
Segment ID
A-B
1.  Surface description (Table 3-1)
FRST
2.  Manning's roughness coeff. for sheet flow, n (Table 3-1)
0.400
3.  Flow Length, L (< 300ft)
ft.
100
4.  Two-year 24-hr rainfall, P2
in.
3.45
5.  Land slope, s
%
3.5%
6.
hr. 0.276
= 0.276
Shallow concentrated flow (assume hyd. radius = depth of flow) 
Segment ID
B-C
C-D
D-E
7.  Surface description
FRST
GRSS
GRSS
8.  Manning's roughness coeff., n
0.100
0.080
0.080
9.  Paved or unpaved
UNPVD
UNPVD
UNPVD
10.  Depth of flow, d (default: d=.4 unpaved, d=.2 pav
ft.
0.4
0.4
0.4
11.  Flow Length, L
ft.
186
30
200
12.  Watercourse slope, s
%
5.9%
27.0%
4.0%
13.  Average velocity, 
fps.
1.96
5.25
2.02
14. 
hr. 0.026 + 0.002 + 0.027 +
+
= 0.055
Channel flow
Pipe
Pipe
Pipe
Pipe
Pipe
Segment ID
15.  Channel Bot. Width (ft) or Pipe Diam. (in)
ft./in.
16.  Horizontal side slope component, z (z horiz:1 vert)
17.  Depth of flow, d
ft.
18.  Cross sectional flow area, A (assume trapazoi
ft.2
19.  Wetted perimeter, Pw
ft.
20.  Hydraulic Radius, 
ft.
21.  Channel slope, s
ft/ft
22.  Manning's roughness coeff., n
23.
fps.
24.  Flow length, L
ft.
25.
hr.
+
+
+
+
= 0.000
26.  Watershed or subarea Tc or Tt (add Tt in steps 6, 14 & 25)
 hr.
0.331
05/28/21
)
(
)
(
007
.
0
4
.
0
5
.
0
2
8
.
0
s
P
nL
Tt 
)
)(
(
49
.1
2
1
3
2
s
d
n
V 
V
L
Tt
*
3600

w
P
A
R 
)
)(
(
49
.1
2
1
3
2
s
R
n
V 
V
L
Tt
*
3600


                 Time of Concentration (Tc) or Travel Time (Tt) Worksheet
Project:
Multifamily Development
By: JRH
Date:
Location:
Hartford Turnpike-Waterford, CT
Checked:
Date:
Circle one:
Present
Developed
Watershed: YD 17.1
Circle one:
T c
Tt
 Subwatershed:   
Sheet flow (applicable to Tc only)
Segment ID
A-B
1.  Surface description (Table 3-1)
FRST
2.  Manning's roughness coeff. for sheet flow, n (Table 3-1)
0.400
3.  Flow Length, L (< 300ft)
ft.
100
4.  Two-year 24-hr rainfall, P2
in.
3.45
5.  Land slope, s
%
3.0%
6.
hr. 0.293
= 0.293
Shallow concentrated flow (assume hyd. radius = depth of flow) 
Segment ID
B-C
C-D
D-E
7.  Surface description
FRST
FRST
GRSS
8.  Manning's roughness coeff., n
0.100
0.100
0.080
9.  Paved or unpaved
UNPVD
UNPVD
UNPVD
10.  Depth of flow, d (default: d=.4 unpaved, d=.2 pav
ft.
0.4
0.4
0.4
11.  Flow Length, L
ft.
65
80
65
12.  Watercourse slope, s
%
1.4%
17.5%
25.0%
13.  Average velocity, 
fps.
0.96
3.38
5.06
14. 
hr. 0.019 + 0.007 + 0.004 +
+
= 0.029
Channel flow
Pipe
Pipe
Pipe
Pipe
Pipe
Segment ID
15.  Channel Bot. Width (ft) or Pipe Diam. (in)
ft./in.
16.  Horizon