Stony Brook Watershed Management Plan FINAL 2009

STONY BROOK WATERSHED MANAGEMENT PLAN 
 
 
MMI #3104-01-1 
 
 
September 25, 2009 
 
 
 
 
 
 
 
 
Prepared for: 
 
Town of Waterford 
15 Rope Ferry Road 
Waterford, Connecticut  06385-286 
 
 
Prepared by: 
 
MILONE & MACBROOM, INC. 
99 Realty Drive 
Cheshire, Connecticut  06410 
(203) 271-1773 
www.miloneandmacbroom.com 

 
 
 
STONY BROOK WATERSHED MANAGEMENT PLAN 
WATERFORD, CONNECTICUT 
SEPTEMBER 2009 
TC-i 
TABLE OF CONTENTS 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
    Page 
 
EXECUTIVE SUMMARY .......................................................................................................ES-1 
 
1.0 
INTRODUCTION 
 
1.1 
Purpose of the Plan .......................................................................................................... 1-1 
1.2 
Data Collection Resources ............................................................................................... 1-1 
1.3 
Organization of Report .................................................................................................... 1-4 
 
2.0 
EXISTING WATERSHED CONDITIONS 
 
2.1 
Watershed Boundaries ..................................................................................................... 2-1 
2.2 
Land Use and Zoning ....................................................................................................... 2-1 
2.3 
Surficial Geology ............................................................................................................. 2-6 
2.4 
Natural Resources ............................................................................................................ 2-9 
2.5 
Coastal Resources .......................................................................................................... 2-12 
 
3.0 
WATERSHED HYDROLOGY AND HYDRAULICS 
 
3.1 
Subwatershed Delineation and Nomenclature ................................................................. 3-1 
3.2 
Flow Conditions ............................................................................................................... 3-1 
3.3 
Time of Concentration ..................................................................................................... 3-5 
 
4.0 
STREAM ASSESSMENT 
 
4.1 
Introduction ...................................................................................................................... 4-1 
4.2 
Methods............................................................................................................................ 4-8 
4.3 
Results ............................................................................................................................ 4-13 
4.4 
Review of Water Quality Monitoring Program – Results and Recommendations ........ 4-24 
 
5.0 
WETLAND SYSTEM EVALUATION 
 
5.1 
Introduction ...................................................................................................................... 5-1 
5.2 
Existing Resources Mapping ........................................................................................... 5-1 
5.3 
Overview of Wetland Assessment Methods .................................................................... 5-5 
5.3.1 The Highway Methodology Workbook – A Descriptive Approach .................... 5-5 
5.3.2 Hydrogeomorphic Approach (HGM) .................................................................. 5-8 
5.3.3 National Wetland Inventory (NWI) ..................................................................... 5-9 
5.3.4 Bulletin No. 9 Method for the Evaluation of Inland Wetlands in Connecticut . 5-10 
5.3.5 Classification of Wetlands and Deepwater Habitats of the United States ......... 5-10 

 
 
 
STONY BROOK WATERSHED MANAGEMENT PLAN 
WATERFORD, CONNECTICUT 
SEPTEMBER 2009 
TC-ii 
5.3.6 MCA Technical Paper Series No. 5 Conserving Pool-Breeding Amphibians in 
Residential and Commercial Developments in the Northeastern United States 5-11 
5.3.7 Study Methods ................................................................................................... 5-12 
5.4 
Overview of Wetland Evaluation and Assessment ........................................................ 5-12 
5.5 
Upper Watershed – Wetlands North of I-95 .................................................................. 5-13 
5.5.1 Watershed SB-90 ............................................................................................... 5-13 
5.5.2 Watershed SB-80 ............................................................................................... 5-25 
5.5.3 Watershed SB-70 ............................................................................................... 5-28 
5.6 
Mid-Watershed – Wetlands South of I-95 ..................................................................... 5-39 
5.6.1 Watershed SB-60 ............................................................................................... 5-39 
5.6.2 Watershed SB-50 ............................................................................................... 5-43 
5.7 
Lower Watershed – Wetlands Near and South of Route 1 ............................................ 5-52 
5.7.1 Watershed SB-40 ............................................................................................... 5-52 
5.7.2 Watershed SB-30 ............................................................................................... 5-58 
5.7.3 Watershed SB-20 ............................................................................................... 5-61 
5.7.4 Watershed SB-10 ............................................................................................... 5-65 
5.8 
Critical Resource Area Identification and Mapping ...................................................... 5-67 
5.8.1 Critical Wetland and Watercourse Systems ....................................................... 5-69 
5.8.2 Unfragmented Areas of High or Unique Resource Value ................................. 5-73 
 
5.8.3 Probable and Observed Vernal Pool Identification ........................................... 5-76 
5.9 
Recommendations .......................................................................................................... 5-76 
5.9.1 Framework for Recommendations ..................................................................... 5-76 
5.9.2 Recommendations for Upland Review Areas and Natural or Enhanced 
 
Vegetative Buffers ............................................................................................. 5-79 
5.9.3 Recommendations for Potential Restoration of Disturbed Wetlands and/or 
 
Buffer Areas ....................................................................................................... 5-84 
5.9.4 Recommendations for Follow-up Investigations and/or Problem Areas ........... 5-85 
 
6.0 
WATERSHED MANAGEMENT AND LOW IMPACT DEVELOPMENT ANALYSIS 
 
6.1 
Introduction ...................................................................................................................... 6-1 
6.2 
Stormwater Management ................................................................................................. 6-2 
6.3 
Low Impact Development (LID) ..................................................................................... 6-5 
6.3.1 Site Planning for LID ........................................................................................... 6-6 
6.3.2 LID Techniques for Development ....................................................................... 6-8 
6.3.3 LID Application in the Stony Brook Watershed .................................................. 6-9 
6.4 
Areas Unsuitable for Septic Systems ............................................................................. 6-13 
 
7.0 
SUMMARY OF FINDINGS AND RECOMMENDATIONS 
 
7.1 
Summary of Findings ....................................................................................................... 7-1 
7.2 
Summary of Recommendations ....................................................................................... 7-6 

 
 
 
STONY BROOK WATERSHED MANAGEMENT PLAN 
WATERFORD, CONNECTICUT 
SEPTEMBER 2009 
TC-iii 
LIST OF FIGURES 
 
Figure ES-1  Stony Brook Watershed Critical Resource Areas ................................................ES-6 
 
Figure 1-1     Stony Brook Watershed Location Map .................................................................. 1-2 
 
Figure 2-1     Stony Brook Watershed Map ................................................................................. 2-2 
Figure 2-2     Stony Brook Watershed Land Use Map ................................................................ 2-3 
Figure 2-3     Stony Brook Watershed Zoning Map  ................................................................... 2-4 
Figure 2-4     Stony Brook Watershed Surficial Geology Map ................................................... 2-8 
Figure 2-5     Stony Brook Watershed Soils Erodibility Map .................................................... 2-10 
Figure 2-6     Stony Brook Watershed NDDB Locations Map .................................................. 2-13 
 
Figure 3-1     Stony Brook Watershed Subwatersheds Locations Map ....................................... 3-2 
Figure 3-2     Stony Brook Watershed FEMA Map ..................................................................... 3-4 
Figure 3-3     Stony Brook Watershed Time of Concentration Flowpaths Map .......................... 3-7 
 
Figure 4-1     Stony Brook Watershed Water Quality Sample Locations Map ........................... 4-2 
 
Figure 5-1     Stony Brook Watershed Palustrine Wetland Communities Map ........................... 5-3 
Figure 5-2     Stony Brook Watershed SB-90 Study Area ......................................................... 5-14 
Figure 5-3     Stony Brook Watershed SB-80 Study Area ......................................................... 5-26 
Figure 5-4     Stony Brook Watershed SB-70 Study Area ......................................................... 5-29 
Figure 5-5     Stony Brook Watershed SB-60 Study Area ......................................................... 5-40 
Figure 5-6     Stony Brook Watershed SB-50 Study Area ......................................................... 5-44 
Figure 5-7     Stony Brook Watershed SB-40 Study Area ......................................................... 5-53 
Figure 5-8     Stony Brook Watershed SB-30 Study Area ......................................................... 5-59 
Figure 5-9     Stony Brook Watershed SB-20 Study Area ......................................................... 5-62 
Figure 5-10   Stony Brook Watershed SB-10 Study Area ......................................................... 5-66 
Figure 5-11   Stony Brook Watershed Critical Resource Areas ................................................ 5-71 
Figure 5-12   Stony Brook Watershed Unfragmented Natural Areas  ....................................... 5-75 
Figure 5-13   Stony Brook Probable Vernal Pool Areas ............................................................ 5-77 
 
Figure 6-1     Stony Brook Watershed Septic Suitability Map .................................................. 6-14 
 
 
LIST OF APPENDICES 
 
Appendix A 
Time of Concentration Computation Worksheets 
Appendix B 
Stony Brook Water Quality Data 
Appendix C 
Wetland System Photographs 

 
 
 
 
STONY BROOK WATERSHED MANAGEMENT PLAN 
WATERFORD, CONNECTICUT 
SEPTEMBER 2009 
ES-1 
EXECUTIVE SUMMARY 
 
Introduction 
 
This document presents the results of Waterford's Stony Brook Watershed Management Plan.  This 
inventory and assessment was undertaken by the Town in an effort to identify water, wetland, and 
upland resources within the Stony Brook Watershed and to evaluate the mechanisms by which 
these resources can be preserved, protected, and regulated at the local level. 
 
This watershed management plan includes an assessment of surface water quality, benthic 
habitat, wetland functions and values, and unfragmented wildlife habitat.  The plan formulates 
strategies for resource management, stormwater quality management, low impact development, 
and septic suitability. 
 
Overview of Watershed 
 
The Stony Brook watershed is approximately 2.86 square miles (1,835 acres) and is located 
within the southwestern part of Waterford.  Stony Brook is the primary perennial watercourse 
within this watershed, and it discharges into Keeny Cove.  The watershed is bounded to the west 
by the Niantic River, to the north by interstate 395, to the east by the Jordan Brook watershed, 
and to the south by Keeny Cove. 
 
Land use and zoning within the Stony Brook watershed differs from north to south, with the 
southern portion being dominated by residential, the central section by residential and large 
vacant parcels, and the northern portion dominated by undeveloped mixed hardwood forests and 
a few commercial properties.  Commercial and industrial developments are primarily located 
along Cross Road, I-95, and Route 1.  The I-95 corridor serves as a major barrier for wetland 
connectivity between the north and central portions of the watershed.  Motor vehicle noise and 
the limited number of culverts beneath I-95 limit and impede wildlife movement between 
wetlands.  Stormwater runoff from the interstate also discharges directly into bordering wetlands 
and watercourses ultimately degrading water quality.  Existing residential development occurs 
primarily south of Route 1 and along Cross Road. 
 
According to the State of Connecticut's surficial materials GIS mapping, the Stony Brook watershed 
consists of approximately 1.91 square miles (1,225 acres) of till and approximately 0.95 square miles 
(610 acres) of stratified drift.  Based on the soil types and surficial geology of the Stony Brook 
watershed, the soil erodibility K values can be classified as moderate.  Most of the soils within the 
watershed have a K value less than 0.3, meaning that they are moderately susceptible to erosion.  
Some of the wetland soils within this watershed do not have a determined K value. 
 
Stream Assessment 
 
Stony Brook and its tributaries begin in red maple/alder/skunk cabbage swamps in a wide 
wetland complex in the upper watershed.  This area is typically flat with wide, heavily vegetated 
floodplains and a network of many small channels full of organic material and fine sediments.  

 
 
 
 
STONY BROOK WATERSHED MANAGEMENT PLAN 
WATERFORD, CONNECTICUT 
SEPTEMBER 2009 
ES-2 
An occasional cascade over boulders is present in the upper watershed.  Instream habitat is 
minimal in the upper watershed but, where present, appears to be of good quality.  The primary 
disturbance in the upper watershed is road crossings consisting of culverts or dirt roads that 
actually travel through the stream channel. 
 
The slope of the watershed increases further down the watershed, and as the channel travels 
towards the I-95 crossing, it becomes well defined and takes on a step-pool pattern.  The main 
stem flows through large boulders and rock vanes and is thus quite stable.  The smaller tributary 
originating to the east in the vicinity of Cross Road is also stable due to large diameter particles 
on the bed and banks.  The water in this tributary has a distinct red color and appears to influence 
water quality from the confluence with the main stem and downstream.  The small channels 
upstream of I-95 typically consist of high quality physical aquatic habitat due to good channel 
stability, intact riparian areas, and floodplains free of human encroachments. 
 
Downstream of the I-95 crossing, the slope of the Stony Brook channel decreases and the 
channel widens.  A riffle-pool pattern is present.  Human alterations to the channel are more 
abundant in the mid to lower watershed.  For example, immediately downstream of the I-95 
culvert, the stream appears to have been channelized alongside a roadway and farm field.  This 
channelization has reduced habitat quality by causing more embeddedness, decreased amount of 
material retained for colonization, and a general decrease in the heterogeneity of the channel bed.  
Signs of excess sediment deposition begin to appear at this location. 
 
As Stony Brook and its tributaries approach Route 1, the channel flattens and takes on a dune-
ripple pattern.  The channel bottom is primarily sand, with some small gravels.  Some point bars 
are evident, indicating sediment deposition and movement through the system.  The aquatic 
habitat upstream of Route 1 is of high quality as the channels travel through large wetland 
complexes that are abundant in organic material and have good floodplain access unimpeded by 
human infrastructure.  The small tributaries entering Stony Brook tend to have silty bottoms and 
deliver loads of fines to the channel.  The small, partially breached dam immediately upstream of 
the Route 1 bridge appears to be holding back excessive amounts of fine sediments. 
 
Downstream of Route 1, both water and habitat quality decline relative to upstream locations.  
The wetland immediately downstream appears deteriorated, containing garbage and an oily 
sheen on the water surface.  The water has a reddish hue, indicative of iron oxide leachate that 
can indicate water pollution or may be due to microbial action within the soil.  Once back into a 
well-defined channel, Stony Brook is relatively deep and wide and consists of fine substrates.  
The stream flows though neighborhoods where it is channelized among homes.  The channel is 
largely disconnected from its floodplain at this location.  Tidal influence is evident in the 
majority of the channel in this stream segment. 
 
Stony Brook is designated as a Class A waterbody (CTDEP, 2002) from its headwaters down to 
Keeny Cove where it enters the Niantic River.  These surface waters are designated for habitat 
for fish and other aquatic life and wildlife, potential drinking water supplies, recreation, 
navigation, and water supply for industry and agriculture. 
 

 
 
 
 
STONY BROOK WATERSHED MANAGEMENT PLAN 
WATERFORD, CONNECTICUT 
SEPTEMBER 2009 
ES-3 
Based on the water quality data collected by the Town of Waterford from 1999 to 2006 
(summary data included in Appendix B) and the rapid field water quality assessment performed 
by Milone & MacBroom, Inc. in June 2007, Stony Brook appears to be mostly meeting this high 
water quality designation.  However, data indicate some water quality issues may exist that 
warrant further study. 
 
The historical water quality data typically show normal natural water quality trends for surface 
waters, with the following observations: 
 
→ 
The water in Stony Brook is slightly acidic, with a pH near 6.5. 
 
→ 
Water temperature is generally cool (< 15 degrees Celsius), with a slight increase moving 
down the watershed as the channel widens and the canopy opens to allow more sun to 
reach the water surface. 
 
→ 
Specific conductivity is low (< 150 μmhos), indicative of cleaner water, with a small 
increase moving downstream, likely due to more dissolved particles present either due to 
geology or increased runoff from road crossings. 
 
→ 
Chloride, a common component of stormwater runoff near roadways where salt is applied 
in the winter months, is low (typically < 20 mg/l), with concentrations increasing moving 
downstream likely due to more runoff from roads and developed areas in the lower 
watershed. 
 
→ 
Dissolved oxygen is high (9.5 mg/l) and consistently above the 5.0 mg/l standard for Class 
A waters. 
 
→ 
Turbidity is at normal levels for clear water (~1 NTU), with typical variability observed 
across data collected in different flows and in different locations. 
 
→ 
E. coli is low and meeting the Class A standards, with some other typical coliform bacteria 
present in higher amounts that are usually associated with watershed geology or normal 
stormwater runoff. 
 
→ 
Phosphorus levels are low (< 0.03 mg/l) and, as usual, the limiting nutrient for plant growth 
in freshwater.  The measured concentrations are near the low limit where nuisance plant 
growth is possible, yet in flowing waters algal blooms typically occur at higher levels of 
total phosphorus (USEPA, 2000).  The shading by the dense riparian canopy typical along 
Stony Brook, combined with the measured phosphorus concentrations, leads to the 
observed plant growth at normal levels that in turn leads to more available substrate for 
colonization by benthic macroinvertebrates.  A normal crop of aquatic plants also reduces 
the likelihood of large dissolved oxygen sags during the day due to respiration. 
 

 
 
 
 
STONY BROOK WATERSHED MANAGEMENT PLAN 
WATERFORD, CONNECTICUT 
SEPTEMBER 2009 
ES-4 
→ 
Nitrogen, in the various forms measured, is present in typical concentrations, with a minor 
increase in nitrate moving downstream.  In general, nutrient levels appear typical for a 
partially developed watershed such as around Stony Brook. 
 
→ 
Metals data collected over the past eight years suggest the potential for both acute and 
chronic toxicity to aquatic life. 
 
Wetland Assessment 
 
The more than 306 acres of wetlands in the watershed represent several ecological categories that 
include palustrine open water, forested, scrub-shrub, and emergent marsh/wet meadow.  The 
relative proportions of each are presented in Table ES-1 below. 
 
TABLE ES-1 
Wetland Types Within the Stony Brook Watershed 
 
 
Wetland 
Type 
 
 
Acreage Within 
the Stony Brook 
Watershed 
 
Percentage 
Within the Stony 
Brook Watershed 
Palustrine Open Water 
4.7 
<1% 
Palustrine Emergent Wetland 
17.4 
<1% 
Palustrine Scrub-Shrub Wetland 
7.6 
<1% 
Palustrine Forested Wetland 
180.0 
10% 
Palustrine Forested/Scrub-shrub Wetland  
88.0 
5% 
Palustrine Scrub-shrub/Emergent Marsh Wetlands 
8.0 
<1% 
 
Site-specific wetland assessment was conducted throughout the Stony Brook watershed.  Wetland 
quality ranged from marginal to excellent, with varying degrees of prior disturbance.  This 
assessment also included the identification of critical wetland systems.  This assessment was a 
broad analysis and is not a substitute for site-specific analysis for proposed development projects. 
 
Critical Wetland Systems 
 
Through decades of well documented research, it has become clear that wetlands and 
watercourses provide a host of important physical and chemical functions as well as a suite of 
beneficial societal values.  These functions and values operate at all scales, from the microscopic 
up to the local and regional landscape.  While most wetlands perform some, or even many, of 
these functions and values, some wetlands, because of their geology, location, vegetation, 
aesthetics, prior impacts, or their history, are inherently more valuable than others.  The 
identification of critical wetland and watercourse systems was completed to provide assistance in 
development of management practices and guidelines that would be applied to land-use decisions 
and conservation practices to protect these important resources within this watershed. 
 
Within this management plan, these special wetlands and watercourses have been referenced as 
"critical wetland systems."  Two objectives were established for identifying critical wetland 

 
 
 
 
STONY BROOK WATERSHED MANAGEMENT PLAN 
WATERFORD, CONNECTICUT 
SEPTEMBER 2009 
ES-5 
systems within the Stony Brook watershed.  These objectives included (1) establishing a network 
of wetland systems that fully represented a diversity of wetland types and that performed key 
ecological and hydrological functions on a local and regional scale; and (2) ensuring local and 
regional wetland biodiversity through designation and management of critical wetland systems.  
The critical resource areas within the Stony Brook watershed are presented in Table ES-2.  In 
addition, Figure ES-1 illustrates the critical resource areas. 
 
TABLE ES-2 
Critical Wetland Systems 
 
Critical 
Wetland 
System 
Watershed 
ID 
Size 
(acres) 
Dominant Wetland 
Cover Types 
Important Functions 
CWS-1 
SB-70 
SB-90 
40.2 
PFO and PSS 
Biodiversity 
Nutrient Retention Flood Flow Alteration 
Production Export 
Fishery Habitat 
CWS-2 
SB-70 
64.3 
PFO, PSS, PEM 
Biodiversity 
Flood Flow Alteration 
Nutrient Retention 
CWS-3 
SB-30 
5.0 
PFO, PSS, POW 
Biodiversity 
Pollutant Renovation 
PFO = Palustrine Forested Wetlands; PSS = Palustrine Scrub-shrub Wetlands; PEM = Palustrine Emergent 
Marsh; POW = Palustrine Open Water 
 
Recommendations for Upland Review Areas and Natural or Enhanced Vegetative Buffers 
 
Recommended upland vegetated buffer distances have been developed to give the commission 
the ability to provide upland protection zones for wetland and watercourses.  Continued 
application of the Town's existing 100-foot upland review area as codified in Section 6.3 of the 
Inland Wetlands and Watercourses regulations is recommended within the Stony Brook 
watershed.  Where proposed land use changes are proximal to wetlands containing vernal pool 
habitat, a review area of 150 feet is recommended to determine if activities are likely to affect 
wetlands and watercourses. 
 
Maintenance of a vegetated buffer area between proposed development and the edge of a 
wetland is recommended to protect the diversity of wetland plant communities, integrity of in-
stream habitats and channel characteristics, and to preserve water quality features including turbidity, 
dissolved oxygen and temperature.  The width of this vegetated buffer area ranges between 50 and 
100 feet, based upon the following factors: 
 
→ the quality of the wetland or watercourse, i.e., the functions and values it provides 
→ water quality features 
→ fishery resources 

LOCATION:
DATE:
SCALE:
SHEET:
MMI#:
MXD:
SOURCE:
99 Realty Drive
Cheshire, Connecticut 06410
(203) 271-1773 Fax: (203) 272-9733
www.miloneandmacbroom.com
§¨¦
95
§¨¦
395
¬«
1
Cross Road
Hartford Road
¬«
85
Cross Road
Niantic River Road
Boston Post Road
Stony Brook
Stony Brook
Keeny
Cove
Niantic River
CWS-3
CWS-2
CWS-1
DEP Bulletin No.40
H:critical_unique.mxd
3104-01
Waterford, CT
Stony Brook
February 2007
1:24,000
Figure ES-1
³
Legend
Stony Brook Drainage Basin
Intermittent Watercourse
Perennial Watercourse
Critical and Unique Areas
.
Critical Wetland Systems

 
 
 
 
STONY BROOK WATERSHED MANAGEMENT PLAN 
WATERFORD, CONNECTICUT 
SEPTEMBER 2009 
ES-7 
 
→ critical wetland habitats 
→ the sensitivity of the wetland to potential impacts from development 
→ the merits, benefits, and particular risks of the proposal, including alternatives to the 
suggested action and available remedial measures 
 
There may be specific property constraints and/or site development objectives that limit the 
availability or opportunity to provide these recommended vegetated upland buffer areas.  In these 
circumstances, it is recommended that the commission carefully evaluate the potential direct and 
indirect impacts of the proposed land use change on the receiving wetland and watercourse and 
require both structural and nonstructural measures to protect the water quality, habitat, and 
functions of the wetland resources. 
 
The suggested upland vegetated buffers for protecting the Stony Brook watershed wetlands and 
watercourses are summarized in Table ES-3. 
 
TABLE ES-3 
Upland Vegetated Buffers 
 
 
Recommended 
Upland Review Area 
(feet) 
Recommended Upland 
Vegetated Buffer 
(feet) 
Recommended 
Conditions and Goals  
Stony Brook Main Stem & 
Riparian Zone 
100 
100 
Densely vegetated 
buffers 
see Section 5.9.2 for 
specifications 
 
Critical Wetland Systems  
100 
100 
Vernal Pools and other 
Amphibian Breeding Areas  
150 
100 to 150 
First Order Streams  
100 
50 to 100 
Intermittent watercourses 
and/or wetlands without 
watercourses, vernal pools, 
and/or critical wetland 
systems 
100 
50 
 
 
Upland vegetated buffer widths are but one important measure for protecting wetlands and 
watercourses from adverse impacts associated with changes in adjacent land use.  Other 
important measures for protecting wetlands and watercourses that should be considered include 
the following: 
 
→ appropriate site planning given existing landscape variables 
 
→ design, installation, monitoring, and maintenance of proper sediment and erosion control 
measures 
 

 
 
 
 
STONY BROOK WATERSHED MANAGEMENT PLAN 
WATERFORD, CONNECTICUT 
SEPTEMBER 2009 
ES-8 
→ design, installation, monitoring, and maintenance of stormwater control and treatment 
measures in keeping with the state's Stormwater Quality Manual and use of appropriate low 
impact development (LID) design practices 
 
Watershed Management and Low Impact Development (LID) 
 
In broad classification, typical impacts to wetlands and water resources due to the alteration of 
hydrologic conditions associated with land development and other activities include degraded water 
quality, unnatural stream channel geomorphic changes, and increased frequency and severity of 
flooding.  All of these potential impacts may also impact aquatic systems and can result in habitat 
loss and degradation and decreased biodiversity. 
 
The practice of stormwater management is intended to mitigate hydrologic impacts resulting from 
changes to the land's surface.  Stormwater management can occur at a watershed scale or at the site 
scale.  At the watershed management scale land use controls, source controls and treatment controls 
are three common methods of stormwater management. 
 
At a site scale, LID is currently the preferred method of managing stormwater.  LID design practices 
make use of creative site planning and design tools that are intended to preserve or reduce the 
changes to a site's hydrology rather than simply providing "end of pipe" treatment or highly 
engineered management systems.  The use of these planning and design tools can often times reduce 
or even eliminate the requirement for more costly and sometimes obtrusive storage, infiltration, or 
end-of-pipe structural practices for the management of stormwater runoff.  They can also result in 
development proposals that better fit the existing characteristics of a site, are aesthetically pleasing, 
and protect the environment. 
 
The following site design elements incorporate LID: 
 
1. Reduce paved areas to the extent possible.  This may include reducing the width of paved roadways 
and cul-de-sac diameters, eliminating on-street parking, promoting use of common driveways, or 
using narrower driveway widths (perhaps nine or 10 feet). 
 
2. Use permeable pavement materials such as grass pavers whenever possible. 
 
3. Avoid compaction of high permeability soils. 
 
4. Minimize the area dedicated for construction easements and stockpile areas. 
 
5. To the extent possible, plan site activities to limit the removal of trees and vegetation. 
 
6. Disconnect impervious areas.  Do not connect roof drains and footing drains into a piped 
drainage system (consider drywells or other infiltration devices).  Provide curbless roads to allow 
sheet flow. 
 
7. Maintain existing topography to the extent possible.  The intent is to maintain runoff travel 
distances, slopes, roughness, and channel shapes whenever possible. 
 

 
 
 
 
STONY BROOK WATERSHED MANAGEMENT PLAN 
WATERFORD, CONNECTICUT 
SEPTEMBER 2009 
ES-9 
8. Maximize the use of open drainage systems such as grass swales. 
 
9. Alter front yard setbacks to move houses forward on a lot to reduce driveway lengths. 
 
Table ES-3 presents a listing of preferred best management practices (BMPs), specific to different 
zoning designations and land uses. 
 
TABLE ES-3 
Preferred Best Management Practices 
 
Residential 
Retail/Industrial 
Both 
Rain Gardens or Barrels 
Pervious Parking 
Grass Swales 
Infiltration Basins or Trenches 
Green Roof Storage 
Deep sump catch basins in roads and parking areas 
Dry Wells 
Single Sidewalks 
Hydrodynamic Separators 
 
Reduction in Building Footprint 
Oil/water separators 
 
Parking Lot Storage 
Created wetland systems 
 
Decentralized Parking 
Bioretention facilities 
 
Bioretention at Parking Lot Islands 
Detention Basins 
 
LID practices can be incorporated into proposed developments in any zone, provided soil types and 
other site conditions are favorable for the proposed LID application.  The most important 
consideration is the ability to capture and collect pollutants in the event of a release.  For this reason, 
the use of infiltration in business and industrial zones needs to be carefully considered based on the 
proposed use of the property. 
 
In many communities across Connecticut, the application of LID principles in the design of 
development plans is hindered by language in the land use regulations that seemingly prohibits their 
use.  The Town of Waterford may wish to incorporate additional LID principles into their existing 
land-use regulations. 
 
Summary of Findings 
 
1. The Town of Waterford has placed a high priority on identifying, protecting, and managing its 
natural resources within the Stony Brook watershed.  The Stony Brook watershed includes 
several large valuable wetland and watercourse systems.  The more than 306 acres of wetlands 
in the watershed represent several ecological categories including palustrine open water, 
forested, scrub-shrub, and emergent marsh/wet meadow systems.  These wetland systems, in 
conjunction with their neighboring uplands, are critical in maintaining a clean and adequate 
supply of surface and ground water. 
 
The Stony Brook watershed is unusual in that the northern portion of the watershed is 
relatively undeveloped with large wetland systems that are natural and unfragmented while the 
central and southern portions of the watershed are more disturbed, developed, and fragmented.  
These differences in land use influence wetland cover types, water quality/quantity, and 
wetland functions and values such as flood control, pollutant renovation, aesthetics, 
recreational opportunities, and wildlife habitat among others. 
 

 
 
 
 
STONY BROOK WATERSHED MANAGEMENT PLAN 
WATERFORD, CONNECTICUT 
SEPTEMBER 2009 
ES-10 
Wetland cover types north of the interstate are predominantly forested and scrub-shrub 
wetlands.  South of the interstate, where anthropogenic disturbances are numerous, wetland 
cover types diversify from forested and scrub-shrub wetlands to include wet meadow, 
emergent marsh, and some open water wetlands.  With the exception of a few wetlands such as 
(CWS-3) and Stony Brook itself, Milone & MacBroom, Inc. (MMI) observed that the overall 
wetland quality declines south of the interstate.  Evidence of more recent disturbances 
(particularly commercial and residential development), invasive species colonization, and 
lower water quality all contribute to the decline of these wetlands. However, that is not to say 
that the wetlands south of the interstate do not still provide important functions and values that 
merit continued protection. 
 
2. Based on the water quality data collected by the Town of Waterford from 1999 to 2006 and the 
rapid field water quality assessment performed by MMI in June 2007, Stony Brook appears, 
for the most part, to be meeting its Class A water quality designation.  However, some data and 
field observations indicate that some water quality issues exist that warrant further 
investigation.  In summary, Stony Brook has: 
 
a. Cool water temperatures 
b. Slightly acidic pH 
c. Low specific conductivity 
d. Low chloride concentrations 
e. High dissolved oxygen 
f. Low E. Coli concentrations 
g. Low phosphorus and nitrogen concentrations 
h. Metals data suggest the potential for both acute and chronic toxicity to aquatic life due to 
high lead and copper concentrations.  However, the data may be inaccurate due to the use 
of nonstandardized techniques with high detection limits.  Further testing, after inspections, 
is likely warranted. 
 
Our field observations indicate some areas of departure from the Class A water quality.  For 
example, the instream bioassessment data indicates a limited abundance and diversity of 
macroinvertebrates within Stony Brook.  MMI also noted strong, red-colored surface waters 
within the upper eastern subwatersheds (tributaries T2 and T3) that appear to be excessive 
given the underlying watershed geology.  Thus, there may be sources of contamination.  
These few instances of potential water quality problems warrant further study because Stony 
Brook is a high quality watercourse and provides an important fishery resource.  It should be 
carefully protected and maintained through appropriate watershed management and careful 
land use planning. 
 
3. It is critical that management efforts extend beyond the banks and flowing water of Stony 
Brooks.  Upstream land uses can have significant hydrologic impacts such as increases or 
decreases in runoff volumes and peak discharge rates as well as nonpoint source pollution.  
Based on our field observations, Stony Brook does experience low-flow impairments, and it is 
important to maintain recharge capabilities within its watershed.  Wetland filling that reduces 
the detention/retention capability in the watershed can increase water surface elevations at 

 
 
 
 
STONY BROOK WATERSHED MANAGEMENT PLAN 
WATERFORD, CONNECTICUT 
SEPTEMBER 2009 
ES-11 
upstream properties and increase erosion downstream as water velocities increase in direct 
response to the loss in conveyance area. Loss of riparian buffers and/or wetlands can impact 
habitat quality and also increase water temperatures as shade-providing vegetation is removed 
as was observed south of I-95. 
 
4. This study provides important mapping and analysis tools of critical environmental resources 
in the Stony Brook watershed.  It provides a baseline of information from which good planning 
can follow.  This is true for individual sites and projects as well as for broad-scale planning at 
the municipal, regional, or statewide level.  It is difficult for planning boards, regulatory 
commissions, and local officials to fully evaluate the merit and/or potential impact of an action 
when it is out of the context of the broader environment in which it is to take place. 
 
5. MMI identified three critical wetland systems (CWS) within the Stony Brook watershed.  
These wetland systems include forested, scrub-shrub, and emergent wetlands, which provide 
important functions including preservation of biodiversity, flood flow alteration, and water 
quality protection and renovation.  The critical resource areas within the Stony Brook 
watershed are described further in Section 5.8.1. 
 
6. The Stony Brook watershed includes several large tracts of land that have been classified in 
this report as unfragmented natural areas.  Each area is described in Section 5.8.2.  
Unfragmented natural areas are a critical component in the conservation of biodiversity on a 
local and regional scale, and they provide and protect essential water supplies.  Virtually the 
entire Stony Brook watershed north of I-95 can be viewed as an unfragmented area of high 
resource value.  Only narrow strips of development exist and these are, for the most part, 
closely confined to Cross Road and the access road north of the highway. 
 
Similarly, the lands south of I-95 and north of the Post Road are largely undeveloped.  As 
viewed here, the "natural" state of the fallow farm fields, farm ponds, and wooded hedgerows 
adds diversity to the landscape and provides opportunities for wildlife not found in the 
forested sections of the watershed.  Additionally, they offer easier access and vantage points 
for public enjoyment. 
 
On a smaller scale, valuable undeveloped lands occur south of the Post Road.  These include 
the high resource value wetlands near Oswegatchie School and beyond Fulmore Drive.  The 
undeveloped woodlands that border these two wetland systems greatly increase the overall 
resource value, although on a more local scale than areas to the north. 
 
7. Vernal pool obligate species such as spotted salamanders and wood frogs were found within 
numerous wetlands in the Stony Brook watershed.  Based on the field investigations, there is a 
higher concentrations of breeding habitat north of I-95.  This is most likely attributed to the 
fact that the wetland and upland habitats north of the interstate have remained natural and 
unfragmented.  South of I-95, the occurrence of amphibian breeding habitat lessens, due to the 
overall change in land use which is predominantly agricultural, residential, and commercial. 
 

 
 
 
 
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SEPTEMBER 2009 
ES-12 
8. Effective watershed management within the Stony Brook watershed involves a multifaceted 
approach that encompasses land uses (past, present, and future); stream and wetland buffers; 
responsible development through adequate site selection, design, and maintenance; stormwater 
BMPs; control of nonstormwater discharges; and control of destructive and unnatural erosion 
and sedimentation. 
 
9. Unchecked or unregulated development within a watershed like Stony Brook can have 
profound negative impacts on the surrounding environment in the form of changes to stream 
flow, flooding, erosion and sedimentation, and deteriorated water quality in streams, ponds, 
and wetlands.  Many communities have attempted to address these issues through local 
zoning or subdivision regulations that prohibit increases in peak stormwater runoff rates.  
However, regulation is only one aspect of the zero-extra runoff concept.  Of equal 
importance is consideration of the individual watershed(s) in which stormwater detention is 
proposed.  Depending on the specific hydrology, detention could actually be detrimental to 
the watershed and even exacerbate downstream flooding impacts. 
 
10. In low impact development, land development design practices for stormwater management 
make use of creative site planning and design tools that are intended to preserve or reduce the 
changes to a site's hydrology rather than simply providing "end of pipe" treatment or highly 
engineered management systems.  Low impact development techniques and practices are 
intended to preserve natural systems and protect resources and their buffer areas through design 
of drainage systems that mimic natural systems.  The selection of specific BMPs varies from site 
to site.  Some applications, such as infiltration systems, may not be appropriate for all land uses 
or all sites. 
 
Summary of Recommendations 
 
1. Based on field investigations and the fact that the Stony Brook main stem is predominantly 
underlain by stratified drift, the watercourse is susceptible to low flow impairment and should 
be managed to increase infiltration.  Fortunately, the main stem has a significant extent of 
stratified drift deposits along the watercourse, such that infiltration and recharge of the aquifers 
would be relatively easy.  The Town may wish to require an assessment by developers of the 
feasibility of incorporating infiltration and recharge into the design of new development in 
areas underlain by stratified drift. 
 
2. Any future regulations that control the quantity and timing of stormwater runoff should be 
carefully crafted to account for the complex hydrologic and hydraulic processes occurring in 
the watershed in question.  In watersheds with alluvial streams, a zero increase in peak flow 
does not preclude channel erosion.  Sensitive streams are also stressed by increased 
stormwater volume and flow duration, even if peak flows are equalized.  Accordingly, each 
of these components should be considered in the development and application of stormwater 
management regulations. 
 
3. The inventory, mapping, and habitat analysis conducted under this Watershed Management 
Plan should be utilized by town leaders and regulatory review boards to help serve as an 

 
 
 
 
STONY BROOK WATERSHED MANAGEMENT PLAN 
WATERFORD, CONNECTICUT 
SEPTEMBER 2009 
ES-13 
active reference tool in reviewing applications, to provide the basis for comparison in the 
review of the applicability and adequacy of current zoning designations, and to distinguish a 
hierarchy of protection for natural resources based on their function and value in their 
respective ecological communities. 
 
4. This plan supports the Town's existing 100-foot upland review area along all wetlands and 
watercourses that have not been identified as having vernal pools and/or other amphibian 
breeding habitat.  For wetland areas designated as having vernal pools and/or other 
amphibian breeding habitat, a 150-foot upland review area is recommended from the edge of 
the pool and/or breeding habitat. 
 
Maintain an upland vegetated buffer between proposed development and the edge of a 
wetland.  Suggested buffer widths range between 50 and 100 feet, based upon the quality of 
the wetland resource, the functions and values the resource provides, water quality and 
vulnerability to land use changes, fishery resources, critical wetland habitats, and the 
resource sensitivity to proposed development. 
 
5. The Town may wish to consider a program to protect its unfragmented natural areas within 
the Stony Brook watershed through land acquisition, where possible, and through its land use 
planning processes.  There are many benefits to maintaining unfragmented natural areas.  
Healthy, ecologically diverse systems that are unfragmented perform important natural, 
abiotic processes such as decomposition of organic matter, soil and sediment creation, 
filtration of ground and surface water, air cleansing, pollutant renovation, and nutrient 
retention.  In addition, these unfragmented lands provide educational and recreational 
opportunities to the public such as bird watching, hiking, skiing, hunting, and fishing. 
 
6. Guidance and suggestions are included in this plan for the promotion of LID in the Stony 
Brook watershed.  The type and scope of LID techniques used may vary from subwatershed 
to subwatershed and site to site depending, not only on the proposed land use, but on the 
geology and topography of the site.  Other factors such as depth to water and depth to 
bedrock are also considerations when evaluating LID application. 

 
 
 
 
STONY BROOK WATERSHED MANAGEMENT PLAN 
WATERFORD, CONNECTICUT 
SEPTEMBER 2009 
PAGE 1-1 
1.0 
INTRODUCTION 
 
1.1 
Purpose of the Plan 
 
The Town of Waterford (the Town) has adopted a multifaceted approach to 
environmental planning in its community.  The Town has retained Milone & MacBroom, 
Inc. (MMI) to conduct a comprehensive inventory and analysis of the water, wetland, and 
upland resources in the Stony Brook watershed and to evaluate the mechanisms by which 
these resources can be preserved, protected, and regulated at the local level.  The Town 
recognizes that not all resources warrant the same level of protection and that higher 
quality resources and unfragmented habitat should logically take priority over low 
quality, isolated features.  The Stony Brook Watershed Management Plan is intended to 
serve as a guidance document to be used for land use planning and decision-making 
purposes.  Figure 1-1 is a location plan showing the geographic limits of the Stony Brook 
watershed. 
 
1.2 
Data Collection Resources 
 
Numerous resources have been accessed to develop a database of information for the 
subject Watershed Management Plan.  The following list provides the principal data 
resources: 
 
¾ Selected geographic information system (GIS) mapping data sets for the Town of 
Waterford and Stony Brook watershed, available through the MAGIC web site, 
including orthophoto coverage, topography, soil types, surficial materials, mapped 
aquifer recharge areas, and Natural Diversity Data Base (NDDB) sensitive areas 
 
¾ Town of Waterford Plan of Preservation, Conservation and Development, dated 
August 1998 

LOCATION:
DATE:
SCALE:
SHEET:
MMI#:
MXD:
SOURCE:
99 Realty Drive
Cheshire, Connecticut 06410
(203) 271-1773 Fax: (203) 272-9733
www.miloneandmacbroom.com
§¨¦
95
§¨¦
395
¬«
1
DEP Bulletin No.40
H:Location.mxd
3104-01
Waterford, CT
Stony Brook
August 2007
1:24,000
Figure 1-1
³
.
Location Map
Stony Brook Watershed

 
 
 
 
STONY BROOK WATERSHED MANAGEMENT PLAN 
WATERFORD, CONNECTICUT 
SEPTEMBER 2009 
PAGE 1-3 
¾ Town of Waterford Regulations for Zoning and Subdivision dated October 2006 and 
Inland Wetlands and Watercourses Regulations dated August 2005 
 
¾ Town of Waterford Zoning District Map dated October 2006 
 
¾ Electronic GIS mapping depicting land use, zoning, parcels, soils, watershed 
boundaries, and other coverages available through the Town of Waterford 
 
¾ Electronic townwide two-foot contour topographic mapping, based on a 1995 aerial 
flight 
 
¾ Information available through the Department of Environmental Protection (DEP) 
Natural Resources Center regarding the mapped resources within the Stony Brook 
watershed 
 
¾ Stormwater system mapping 
 
¾ Water quality data for Stony Brook, available from the Town 
 
¾ Natural Resources Conservation Service (NRCS, formerly Soil Conservation Service, 
SCS) soils mapping 
 
¾ Niantic Quadrangle Coastal Resource Map dated 1970 
 
In addition to the above data, mapping, and reports, field data collection was undertaken 
to perform a stream assessment, vernal pool study, wetland reconnaissance, and visual 
inspection of general watershed features (land uses, drainage systems, vegetation, etc.).  
The analysis and recommendations in this document are based upon a combination of 
available data in combination with these field efforts. 

 
 
 
 
STONY BROOK WATERSHED MANAGEMENT PLAN 
WATERFORD, CONNECTICUT 
SEPTEMBER 2009 
PAGE 1-4 
1.3 
Organization of Report 
 
The subject Watershed Management Plan has been organized as follows: 
 
Section 1.0 of this plan describes the scope and purpose of the plan; summarizes the 
sources of information, data, reports, and resourc