Jordan Brook Watershed Mgt Plan Scanned Version

6
FINAL REPORT
FEBRUARY 2000
Prepared By:
Fuss & O’Neill, Inc.
146 Hartford Road
Manchester, CT 06040
In Conjunction With:
Marine and Freshwater Research Service
276 State Street
Guilford, CT 06437
Fuss & O'Neill Inc. Consulting Engineers
446 Hartford Road, Manchester, CT 06040-5921
TEL 860 646-2469 FAX 860 643-6313
1200 Converse Street, Longmeadow, MA 01106-1721
TeL 413 567-9886 FAX 413 567-8936
140 Sherman Street, Fairfield, CT 06430-5822
TEL 203 256-1790 Fax 203 256-5742
410 North Broadway, East Providence, RI 02914
Tet 401 434-9760 Fax 401 434-9920
JORDAN BROOK WATERSHED MANAGEMENT PLAN
TOWN OF WATERFORD, CONNECTICUT

EXECUTIVE SUMMARY ....... ese e eee cet e ree ene eet eee n enn te nenene Vv
1.0 INTRODUCTION 2... .. cece cece rece e ence een ene eee ne ne eenneee 1
2.0 CURRENT WATERSHED CONDITIONS .......... 0 cee eeee eee ree enneee 2
2.1 Watershed Description ....6. 6.0... cece eee n eee n nee ener eee ertenees 2
2.2 Water Quality Classifications 00... 6. cece eee tenn ene ees 2
2.3 Land Use wi cece ccc cece ee cee eee teen renee teen nee e eens 3
2.4 Aquifers... cece cece cece ener een n tent e een eens 4
3.0 WATERSHED EVALUATION .......... cece cee cece eee e ene e en nnes 4
3.1 Jordan Brook 12... ccc cece ee teen eee teen etn e een eee e tenes 4
3.1.1 Field Observations ....... ccc cece eee tere ete n ene ences 4
3.1.1.1 Areas of Erosion/Sedimentation ......... 000. ee eens 5
3.1.1.2 Areas of Significant Litter and Debris ................ 5
3.1.1.3 Evidence of Flooding ........ 0c cess ee cere een eens 6
3.1.2 Water Quality 0.0... ccc ccc cece eee te tenes 6
3.1.2.1 Analysis of Parameters-of-Concern .........- ++ eee ee 7
3.1.2.2 Effects of Imperviousness on Surface Water Quality ..... 8
3.1.2.3 Land Use Evaluation ....... 0.0 cess cece eee een enene 9
3.1.2.4 Subwatershed Evaluation ........ 00. cence eee eens 9
3.2 Inland Wetlands ...... 0... cece ete eee te terete ene ennnee 10
3.2.1 Wetland Resources ........ ce cee cece ee ete eet eee nenaee 10
3.2.2 Evaluation of Resources ........ cece ccc e eter ee etnies 11
3.2.2.1 Evaluation Procedures ........:ceee eee e eter er eens 13
3.2.3 Significant Resources ...... ee cece cece ee eee ee teen eee ee 13
4.0 HYDROLOGIC EVALUATION OF JORDAN BROOK ...... 0. cece eee ees 15
4.1 TR-20 Model Input Data . 0... cece cece tence ene 15
4.2 TR-20 Model Results ....... cece cece eee ete eect erence ene 16
4.3 Stormwater Quantity Control Evaluation ......... 0. eee serene eens 17
4.3.1 Methodology ........ ccc sce c eee teeter eee ene nnn nene 17
4.3.2 Conclusions ...... cece eee rere eee ene eens 18
5.0 STORMWATER QUALITY EVALUATION ........ ccc secre cece eee neee 18
5.1 Future Watershed Land Use ........ 05. c cece cece ee etre nee eeee 18
5.2 Land Use Pollutants-of-Concern 1.0... 0.00 cece seen eect tence ane 19
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5.3. Pollutant Loading Evaluation .............. ccc eeeeee eens
5.3.1 Model Description ....... 0. 00s cece ec e ene e ne eenee
5.3.2 Current Pollutant Loadings ......... 0c cere ee eeeeee
5.3.3 Future Pollutant Loadings ...... 00sec cece sence cece
5.4 Conclusions ....... 0c ccc cece eee ence eect eee een ena
6.0 OTHER WATERSHED ISSUES .........: cece eee eee enna
6.1 Aquifer Protection ...... 0... ccc eee eee eee eee eeeene
6.1.1 Land Uses of Concern 0.0... 0. cee eee cee eee eee
6.1.2 Groundwater Recharge ..... 0... cece eee e eee eens
6.2 Open Space Evaluation ....... ce cece eee eect eee ents
6.2.1 Existing Conditions 0.0.0.0... ccc cece eee eens
6.2.2 Watershed Evaluation .......... 0c cee ence ee ee eens
6.2.3 Conclusions ....... 0. cece cece eee eect e etree
7.0 RECOMMENDED PLAN ........ 0c. cc cece eee ere eee erenenee
71 Continue to Monitor Water Quality .... 0... cc cece ee eee ee ees
7.2 Control Stormwater Quality 0... ccc ccc cece ee tere eens
7.2.1 Base Level Controls ....... 0... c cece e cee eee eens
7.2.2 Additional Stormwater Quality Controls ...............
7.2.2.1 Secondary Stormwater Quality Controls .......
7.2.2.2 Tertiary Stormwater Quality Controls .........
7.2.3 Stormwater Quality Control Technologies .............
7.2.4 Selection Criteria for Level of Controls .............45.
7.2.4.1 Receiving Water Resources ..........e scenes
7.24.2 Land Use... . ccc cee eee teen ee ee eee ene
7.2.4.3 Level of Imperviousness ........ 0000s eee ee
7.2.4.4 Size of Development ............. 0.00 ee eee
7.3 Maintain Groundwater Base Flows ..........ec eee eee ee eens
7.4 Maintain Pre-Development Peak Discharge Rates .............
7.5 Acquire Additional Open Space ....... cece eee e cece ee eees
7.6 Other Wetland Protection Techniques ......... 000: secu cece
7.6.1 Upland Protection Zones 1.1.0... . cece eee eee eens
7.6.2 Biological Inventories ......... 0. esac eee cece eens
8.0 REFERENCES ........ cece cece ener eee e enn e ee een ees
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1 Summary of Watershed Land Uses 3
2 Jordan Brook Sampling Stations 6
3 Summary of Impervious Area 8
4 Current Imperviousness of Watershed Land Uses 9
5 Current Imperviousness of Jordan Brook Subwatersheds 9
6 Inland Wetlands Summary 13
7 Critical Detention Locations 16
8 TR-20 Model Input Parameters 16
9 Summary of Computed Existing Peak Flows 16
10 Comparison of Predicted Peak Flows 16
11 Waterford Zoning Classifications 18
12 Land Use Pollutant Loading Factors 20
13 Land Use Pollutant Reduction Factors 21
14 Summary of Current Pollutant Loadings 22
15 Zoning-Based Land Uses 22
16 Summary of Future Pollutant Loadings 22
17 Summary of Future Unit Area Loadings 23
18 Aquifer Protection Areas - Land Uses of Concern 24
19 Rating Matrix of Potential Open Space Areas 27
20 Stormwater Quality Control Selection Criteria 31
21 Common Stormwater Quality Controls 34
FIGURES FOLLOWING PAGE
1 Watershed Location Map 2
2 Watershed Land Use Classifications 3
3 Potential Groundwater Aquifers 4
4 Water Quality Monitoring Results - Average Phosphorous Concentration 7
5 Water Quality Monitoring Results - Average Turbidity and TSS Concentrations 7
6 Water Quality Monitoring Results - Average Total Coliform Concentration 7
7 Water Quality Monitoring Results - Average Nitrate Concentration 7
8 Water Quality Monitoring Results - Average DO and BOD Concentrations 7
9 Water Quality Monitoring Results - Average Conductivity Concentration 7
10 Water Quality Monitoring Results - Average Chloride Concentration 7
11 Jordan Brook Subwatersheds 9
12 Effect of Development on Runoff Hydrographs 17
13 Waterford Zoning Classifications 18
14 Proposed Greenway Corridors and Open Space Parcels 27
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iii

Acs rAAMYOWS
GIS Database User’s Guide
CTDEP Water Quality Standards
Description of Wetlands
Functional Value Scores
Correspondence with State of Connecticut
CTDEP Guidelines for Upland Review Area Regulations
TR-20 Model Documentation
Connecticut Water Resources Bulletin No. 15
Stormwater BMP Operation and Maintenance Guidelines
CTDEP Oil/Water Separator Regulations
State of Connecticut Draft Aquifer Protection Regulations
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iv

e
a
e at
e y good co d t o .
Large areas of the watershed remain undeveloped, especially in its northern reaches.
Uncontrolled future residential, commercial, or industrial development in the watershed would
increase pollutant loadings from stormwater runoff to receiving wetlands and watercourses,
reduce groundwater base flows that are necessary to maintain dry weather flows in streams,
increase peak flows and flooding, and continue to encroach on upland fringe areas that “screen”
wetlands from development.
The purpose of this study was to evaluate existing watershed resources and develop a
recommended plan to protect those resources from potential impacts as identified above. The
following paragraphs summarize the major findings and recommendations of this study.
° Wetland areas generally in good condition:
Wetland areas within the watershed remain in good condition and many have features
that justify the wetlands as having special significance. Some wetlands appear to have
been impacted by encroaching development and water quality impacts, and other
wetlands would be sensitive to any future impacts to water quality.
° Surface water quality generally fishable and drinkable:
Surface water quality in the watershed generally meets “fishable and drinkable”
standards established for the State of Connecticut with the exception of total coliforms.
Since the source of total coliform can include non-pollution sources such as plant
matter, this finding is not conclusive evidence of sanitary contamination.
e Development impacts water quality:
While surface water quality still meets standards, in-stream concentrations of pollutants
increase downstream as development and impervious surfaces increase. Based on
modeling of future pollutant loads, stormwater pollutant loadings could increase by
more than 100% for zinc and between 30 and 50% for phosphorous, copper, and lead
with future development. Copper, lead, and zinc can be toxic to aquatic life at certain
concentrations in aqueous form. Phosphorous is a limiting nutrient for algal growth in
surface water impoundments.
° Water Quality Management Plan:
A surface water quality management plan has been developed that specifies the levels
of controls that would be recommended to be implemented based on the level of risk
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0. Secondary controls would apply to developments with greater risk for water
quality impacts and would require a minimum of 80% removal of total
suspended solids.
Il. Tertiary controls would apply to developments with the greatest risk for water
quality impacts and would require developers to demonstrate no net increase in
pollutant loads from pre-development conditions.
Continue surface water quality monitoring:
Surface water quality should continue to be monitored to evaluate trends in water quality
and confirm that new developments have appropriate controls.
No net increase in peak flows:
Evidence of flooding and channel scour was observed during watershed visits. It is
recommended that future developments demonstrate no net increase in peak flows at
downstream points-of-concern, The number of downstream points-of-concern to be
evaluated is proposed to be dependant on the size of the development and its potential
to increase flooding risk. A watershed-wide hydrologic model has been developed that
should be incorporated into future evaluations.
Maintain pre-development groundwater base flows:
Pre-development groundwater base flows should also be maintained. At a minimum,
“clean” roof runoff should be infiltrated into the ground. This approach does not require
a complicated technical evaluation of current on-site infiltration to groundwater, would
typically maintain or increase base flows, and would minimize the risk of groundwater
pollution by infiltrating only clean runoff.
Designate upland areas as open space and implement Upland Protection Zone:
A number of upland areas in the watershed would provide value as open space by
improving the value of watershed wetlands by screening developments, providing fringe
habitat, maintaining wildlife access, and improving human access to wetlands of special
significance. Upland areas that could provide value have been evaluated and ranked in
terms of their importance. A 50-foot Upland Protection Zone is also recommended for
all wetlands and a 100-foot Upland Protection Zone is recommended for perennial
streams, Factors which should be considered in adjusting these widths are discussed.
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vi

good condition.
Large areas of the watershed remain undeveloped especially in its northern reaches.
Uncontrolled future residential, commercial, or industrial development in the watershed would
increase pollutant loadings from stormwater runoff to receiving wetlands and watercourses,
reduce groundwater base flows that are necessary to maintain dry weather flows in streams,
increase peak flows and flooding, and continue to encroach on upland fringe areas that “screen”
wetlands from development.
The goal of this study was to evaluate existing wetland resources in the watershed and develop
a plan to protect those resources from impacts related to future development. In order to
conduct this study, the Town of Waterford retained Fuss & O’Neill, Inc. whose team included
Dr, Priscilla Baillie of Marine and Freshwater Research Service. During this study several
workshops were conducted with the project team and Fuss & O’Neill in order to develop a plan
that best met the Town’s needs and addressed specific issues in this watershed. Representatives
from the Town of Waterford during these workshops included professional staff from the
Waterford Planning Department as well as representatives from the Town’s Conservation
Commission and Department of Public Works.
This report outlines the results of the study. Current watershed conditions are evaluated,
including wetlands, stream water quality, land use, and hydrologic conditions (Sections 2.0 and
3.0). A hydrologic model of the watershed was developed to address stormwater quantity
management issues (Section 4.0). A stormwater quality control plan was developed for the
Town to protect stormwater quality from future development in the Jordan Brook watershed
(Section 5.0). Other watershed issues addressed as part of this project and incorporated into
the watershed management plan include aquifer protection and open space planning (Section
6.0). The recommended watershed management plan is presented in Section 7.0. A
Geographical Information System database has also been developed for this watershed that
incorporates the results of this study. A user’s guide and instructions for the database are
attached as Appendix A of this report.
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oriented in a north-south direction, extending approximately 5.5 miles from its headwaters near
Waterford’s northern border with Montville, south to Jordan Cove which discharges to the Long
Island Sound.
The upper reaches of the Jordan Brook watershed are largely undeveloped. Jordan Brook
crosses several highways, including Interstate-95, Interstate-395, and State Route 85 through
the central portion of the watershed. Development and corresponding impervious areas increase
as the brook flows south. Jordan Brook reaches its confluence with Nevins Brook
approximately 400 feet upstream of Jordan Cove. Nevins Brook drains the southeastern portion
of the watershed. Several smaller tributaries oriented in an east-west direction feed the central
and southern portions of Jordan Brook. Figure | is a location map of the Jordan Brook
watershed.
The northern half of the watershed is hilly and predominantly wooded, with a maximum
elevation of approximately 380 feet atop Konomoc Hill near the Jordan Brook headwaters. The
watershed topography gradually flattens south of Interstate-95 in the more developed portions
of the watershed. Several impoundments are located in the upper and lower reaches of Jordan
Brook. Tyack Swamp is a large wetland situated between Interstate-95 and Manitock Hill on
the western side of the watershed. Two interconnected wetland/marsh systems located east of
Clark Lane and south of Post Road (U.S. Route 1) comprise the southeastern corner of the
watershed adjacent to the City of New London.
2.2 Water Quality Classifications
The surface waters of Jordan Brook and most of Nevins Brook are classified by the Connecticut
Department of Environmental Protection (CTDEP) as B/A (CTDEP, 1986) with some upstream
reaches of Nevins Brook classified as A. Inland surface waters classified by the CTDEP as B/A
are those that may not meet Class A water quality criteria or one or more designated uses for
Class A waters. Class A water quality standards and designated uses are provided in
Appendix B. The goal for B/A surface waters is achievement of Class A criteria and attainment
of Class A designated uses. Class A waters are a potential drinking water supply and support
designated uses such as fish and wildlife habitat, recreational use, agricultural/industrial supply,
and navigation (CTDEP, 1997). For the purposes of this study, water quality standards for Class
A surface waters are used to evaluate water quality impacts since this level of quality is the
stated goal for these waters.
Groundwater throughout a majority of the watershed is classified by the CTDEP as GA,
however several areas in the northern half of the watershed have been classified as “GA, GAA
may not meet current standards” (CTDEP, 1986). Such groundwater may not meet the GA or
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JORDAN
BROOK
WATERSHED
BOUNDARY
Station 8: SOUTH END OF DAM AT MILL
POND.
MAP REFERENCE:
THIS MAP WAS PREPARED FROM THE FOLLOWING
7.5 MINUTE SERIES TOPOGRAPHIC MAP:
MONTVILLE, CONN. 1983,
NIANTIC, CONN.-N.Y. 1983
NEW LONDON, CONN.-N.Y. 1984
LEGEND:
@ WATER QUALITY MONITORING STATION
© CRITICAL DETENTION LOCATION
SCALE = 1: 48000
2 MILE
8000
NEVINS
BROOK
Quadrangle Location
FIGURE 1
JORDAN
COVE
T46 HARTFORD ROAD, MANCHESTER, CONNECTICUT 06040
(860)846-2469
46) Fuss & ONeill Inc. Consulting Engineers
LOCATION MAP
JORDAN BROOK WATERSHED
JORDAN BROOK WATERSHED MANAGEMENT PLAN
WATERFORD CONNECTICUT
PROJ. NO. 93154A2 DATED : OCTOBER 1998 SCALE: 1"= 4000
J:ADWG\P93\93154\A2\FIGURE1,PPT

Watershed land use affects the quantity and quality of stormwater generated in the watershed.
Factors such as impervious area, drainage system, development characteristics, traffic volume,
air emissions, and exposure of other pollutant sources are dependent on land use, Land use
mapping for the watershed was provided by the Town of Waterford. Several of the Town-
defined land use categories were field-verified to determine the nature or level of development
(e.g., undeveloped, commercial, residential, etc.) associated with these land uses.
Figure 2 depicts the land use categories within the Jordan Brook watershed. The percentages
of each land use within the watershed are summarized in Table 1. As shown in the table,
approximately 76 percent of the watershed consists of a combination of undeveloped, single
family residential, and public facility land uses. Approximately 17 percent of the watershed
consists of commercial, industrial and multi-family land uses. Highways and roads comprise
approximately 7 percent of the watershed area,
In general, the level of development in the watershed increases proceeding from the headwaters
to the lower reaches of the watershed. The northern portion of the watershed consists primarily
of undeveloped woodland, with some residential areas along the eastern side of the watershed.
Interstate 395 passes through the northern portion of the watershed. A combination of
undeveloped woodland/meadows and residential land uses characterize the area between
Interstate-395 and State Route 85. Commercial and industrial/manufacturing developments are
located along the northern stretch of Route 85, which passes in a southeasterly direction through
the northern half of the town. The area between Route 85 and Interstate 95, which passes in an
east-west direction through the center of the watershed, includes several major commercial
developments such as Crystal Mall, a large regional mall, and other high-traffic mall
developments (i.e., Home Depot, Wal-Mart, Crossroads Centre).
The southern half of the watershed, roughly defined as the area south of Interstate-95, is
characterized by a mixture of undeveloped land, open space, and residential and commercial
land uses. The areas of highest intensity residential development are located north and south
of Post Road (U.S. Route 1), which passes through the southern portion of the watershed in an
east-west direction. Numerous commercial retail developments are located along Post Road,
with several major shopping centers situated near the intersection of Post Road and State Route
156. A number of municipally-owned lands, including schools and parks, are also located in
this area of the watershed. Additionally, the Northeast Rail Corridor traverses the watershed
south of Route 1.
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O FUSS & O'NEILL INC. Consuiting Engineers
Surficial Materials
> __ ALLUW/SAND+GRAVEL THICK TILL
SAND+GRAVEL TILL
SAND+GRAVEUSANDIFINES “{))) TILL, SAND+GRAVEL, BOULDERS
Gs swap @]] waer
Source:
Surficial Materials Map of Connectciut,
U.S. Geological Survey, Stone et al., 1992.
446 HARTFORD ROAD, MANCHESTER, CONNECTICUT 06040
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meltwater deposits such as gravel, sand, and silt and floodplain alluvium generally correspond
to the major groundwater aquifers in Connecticut. As such, areas classified as glacial meltwater
and floodplain alluvium deposits in the watershed were characterized as potential groundwater
aquifer areas.
Figure 3 illustrates the distribution of potential groundwater aquifers across the Jordan Brook
watershed, As shown in Figure 3, potential groundwater aquifers are generally concentrated
along Jordan Brook, Nevins Brook, and their associated tributaries. In the northern portion of
the watershed, sand and gravel deposits are confined to a relatively narrow corridor which
follows the main stem of Jordan Brook. A more widespread area of potential groundwater
aquifer deposits exists in the southem portion of the watershed. The potential groundwater
aquifers in the southern half of the watershed are also located in some of the most highly
developed areas in the watershed.
In its 1998 Plan of Preservation, Conservation & Development, the Town of Waterford
identified potential public water supply well sites immediately north of the intersection of
Jordan Brook and Interstate 95 and near the confluence of Jordan and Nevins Brook. These
sites correspond to areas having some of the thickest stratified deposits in the watershed, which
may provide significant yields for future public water supply (Town of Waterford, 1998).
3.0 WATERSHED EVALUATION
Jordan Brook and its associated wetlands were field visited during the course of this study by
members of the project team. Additionally, the Town of Waterford currently monitors water
quality in Jordan Brook at selected sampling locations. Results of the field evaluations and
water quality monitoring are described in this section.
3.1 Jordan Brook
3.1.1 Field Observations
Fuss & O’Neill personnel conducted a site visit of the Jordan Brook watershed on March 12,
1998. The purpose of the site visit was to observe the general conditions of Jordan Brook and
its surrounding watershed and to identify:
. Potential sources of stormwater pollution in the watershed (e.g. areas of
erosion/sedimentation and areas of significant litter/debris), and
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Vacant 1358 27.7%
PA-490 (Undeveloped) 981 20.0%
Single Family 613 12.5%
Public Land 415 8.4%
Road (Public ROW) 250 5.1%
Commercial Retail 241 4.9%
Mall 194 4.0%
Public Facilities 188 3.8%
Utility Transmission 125 2.5%
Private Open Space 115 2.3%
Cemetery 87 1.8%
Interstate Highway 83 1.7%
Multi-Family 83 1.7%
Industrial Manufacturing 81 1.7%
Mixed Use 24 0.5%
Private Facilities 22 0.5%
Land Trust/Public Easement 16 0.3%
Public Utility 14 0.3%
Mobile Home 11 0.2%
Water 3 0.1%
Unknown 2 0.05%
Industrial Warehouse 1 0.02%
Commercial Hospitality 1 0.02%
Commercial Office 1 0.02%
(Total (1) 4908 100.0%
Notes:
(1) Table Excludes area of watershed located in New London.
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FO
Cametery
G&D
Land Use Classifications
Comm Hospitality
D>
>
@
PA490
Private Facilities
Private Open Space
Comm Office Public Facilities
Comm Retail (ae) Public Land
Highway Public Utility
Ind Manufacturing Road
Ind Warehouse ED Single Family
Land Trust/Pub Easmt Unknown
Mall GQ_ viii transmission
Mixed Use C3 Vacant
= Water
Scale
2000 4000 Feet
FUSS & O'NEILL INC. cConsutting Engineers
446 HARTFORD ROAD, MANCHESTER, CONNECTICUT 06040
wrnFendo.com FIGURE 2

In general, the streambanks along Jordan Brook and its tributaries at the observed locations are
either highly vegetated in undeveloped areas or lined with riprap or concrete in more developed
areas. The site walkover was performed during dry weather, approximately 24 to 48 hours
following a significant rainfall event. Asa result, Jordan Brook and its tributaries were flowing
nearly full at the time of the inspection.
Evidence of sediment input and erosion in Jordan Brook from adjacent upland areas was
observed at several major road crossings. This evidence included in-stream sand bars,
streambank gully erosion, and exposed (unvegetated) earthen areas adjacent to the brook that
were observed at the following locations:
. Jordan Brook at Interstate-95
. Jordan Brook at Footbridge in Incomplete Subdivision near former Waterford Airport
Property
. Jordan Brook at Route 1
. Jordan Brook at Route 156 (Rope Ferry Road)
. Jordan Brook Tributary (upper “Fenger Brook”) at Route 1
The identified crossings are located in developed areas of the watershed south of Interstate-95.
These observations are consistent with the relationship between sediment loading and level of
development.
3.1.1.2 Areas of Significant Litter and Debris
Accumulated litter and debris was observed along the stream banks at several of the inspected
stream crossings. The most significant quantities of litter and debris, which generally consisted
of paper, styrofoam, plastic and other small, floatable materials, were noted at major road
crossings and in the more developed areas of the watershed (i.e., south of Route 1). These
locations included:
. Jordan Brook at Cross Road
. Jordan Brook at Route 85
. Jordan Brook Tributary at Ellen Ward Road
. Nevins Brook at Route 1
. Jordan Brook Tributary at Miner Lane
. Jordan Brook Tributary at Route 1
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Brook at Route 1 east of Reynolds Lane. Jordan Brook, the stormwater discharge from Route
1 or the adjacent cemetery, and the outlet of a wetland area converge immediately upstream of
this culvert crossing. Several large uprooted trees, accumulated brush and organic debris, and
matted overbank vegetation were observed, which are indicative of high-velocity flows and
backwater associated with prior flooding. A stone retaining wall along the west bank of Jordan
Brook immediately upstream of the crossing (single concrete box culvert) appears to restrict or
channelize flood flows in this area.
3.1.2 Water Quality
The Town of Waterford currently conducts semiannual water quality monitoring of Jordan
Brook. Surface water samples are collected at eight stations along Jordan Brook, which are
shown on Figure 1. The sampling stations are located primarily at major road crossings and are
approximately evenly spaced along Jordan Brook. The Jordan Brook sampling stations are
listed (from upstream to downstream) in Table 2. Nine rounds of water samples have been
collected since monitoring began in 1993. These samples were analyzed for the following
parameters.
Total Phosphorous Copper
Total Suspended Solids Biochemical Oxygen Demand
Turbidity Chemical Oxygen Demand
Total Coliforms Nitrate
Fecal Coliforms Dissolved Oxygen
Fecal Streptococci Oxygen Saturation
Sodium Color
Tron Odor
Manganese Temperature
Conductivity Alkalinity
pH Hardness
Chloride
In order to evaluate Jordan Brook water quality, seven critical parameters were analyzed. These
parameters were selected as they have greater potential to impact uses of the stream and are
more likely to be affected by development as opposed to natural sources. The parameters-of-
concern that were analyzed are total phosphorous, turbidity, total coliforms, dissolved oxygen,
conductivity, chloride, and copper.
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Station Number
Description
Stream crossing in woods, east of Konomoc Hill
Stream crossing in woods northeast of Industrial Drive cul de sac
Downstream of Douglas Lane
Downstream of Cross Road
Downstream of Parkway South
Downstream of Post Road
Upstream of Rope Ferry Road
(oe i ed oe a ee Oe
South end of dam at Mill Pond
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classified as either “wet” or “dry”. For comparison purposes, the average concentrations from
these three dry and one wet weather events were plotted against the average concentration of all
nine events. It should be noted that the wet weather concentrations are based on only one event
and, therefore, are not statistically valid compared to the other average concentrations.
° Phosphorous: Phosphorous is typically the limiting nutrient in freshwater systems. The
State of Connecticut Water Quality Standards (effective April 12, 1996) classify surface
waters with 0.03 to 0.05 mg/l of total phosphorous as eutrophic and highly enriched with
nutrients. Higher levels of phosphorous are considered highly eutrophic. Eutrophic
conditions lead to algal blooms and dissolved oxygen depletion in impoundments,
In this watershed, average phosphorous concentrations are generally above 0.03 mg/l.
A number of impoundments exist in the watershed where significantly increased
phosphorous loads could lead to increased potential for eutrophication. However, these
elevated levels are mostly due to high concentration results from two sampling events,
9/24/96 and 9/23/97. Phosphorous concentrations during other sampling events were
generally below 0.03 mg/l.
° Turbidity: Surface water criteria specified in the Connecticut Water Quality Standards
establish a turbidity standard of 5 NTU over ambient levels. Average concentrations in
Jordan Brook are below this level.
° Total Coliforms: The standard for total coliforms in Class A streams is 500 counts/100
ml based on the Connecticut Water Quality Standards. Average water quality in the
stream exceeded this standard at most stations. Dry and wet weather concentrations
increased in the more developed downstream reaches of the watershed.
. Nitrate: While no criteria have been established for nitrate in the Connecticut Water
Quality Standards, nitrogen is a limiting nutrient in salt water systems. Nitrate levels
were significantly higher during the one wet weather event measured. Nitrate levels also
increase with development. Septage lagoons are also shown on USGS mapping as being
near the reach of brook where nitrate levels increase (stations 4 and 5).
. Dissolved Oxygen: All dissolved oxygen concentrations were above 5 mg/l which is
the minimum criteria per the Connecticut Water Quality Standards. Concentrations
generally decreased through developed areas of the watershed. This is likely due to the
water temperature increase that is typically found through developed areas.
93154\A2\EVM1203B.WPD
Corres. 7

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° Copper: Copper levels detected in the brook were either not detected or were detected
just at detection limits. Detection limits used by the laboratory were equivalent to
CTDEP chronic water quality criteria (0.0048 mg/l). No figure is provided for copper
since levels of copper were never measured above detection limits.
In summary, with the exception of some elevated levels of phosphorous and coliforms, stream
water quality appears to be within CTDEP Class A surface water quality criteria. However,
current watershed development has increased levels of some of these parameters.
The data available to determine wet and dry weather impacts is limited. Future sampling should
be conducted in a manner that would better determine wet and dry weather impacts.
While total coliform levels exceed Class A surface water quality criteria, these levels may not
be attributable to a man-made source of pollution. Total coliform sources include degrading
plant matter, as well as sewage and other man-made sources. In addition, since the elevated
phosphorous levels are caused by only two of the nine sampling events, the elevated
phosphorous levels may not be representative of actual stream conditions.
Some modifications to the monitoring program are recommended to better determine wet
weather impacts and bacteria and phosphorous impacts in this surface water. The recommended.
water quality monitoring program is described in Section 7.1.
3.1.2.2 Effects of Imperviousness on Surface Water Quality
Research has found a strong correlation between impervious surfaces in a watershed and water
quality in downgradient water resources. Literature reports that when 10 to 30% of the
watershed consists of impervious surfaces, downgradient water resources are typically found
to be impacted. When more than 30% of the watershed consists of impervious surfaces,
downgradient water resources have been found to be degraded.
The average amount of impervious surface (i.e., roof and paved areas) associated with each
watershed land use was determined using GIS land use and impervious surface data provided
by the Town. Table 3 summarizes the percentage of the watershed that is impervious above
each existing sampling station. For the purposes of this study, impervious areas are defined as
roof and paved areas. The percent impervious represents the total impervious area in the
watershed above the sampling station. The percent impervious is computed by dividing the
impervious areas above the sampling station by the total watershed area above that station.
93154\A2\EVM1203B.WPD
Corres. 8

FEBRUARY 2000
Total Impervious %
Station Area Area Impervious
(Sq-ft) (Sq-ft) (A)
1 5,820,000 186,000 3%
2 13,639,000 212,000 2%
3 29,216,000 1,340,000 5%
4 39,871,000 2,441,000 6%
5 72,550,000 5,008,000 7%
6 101,870,000 6,658,000 7%
7 172,093,000 16,568,000 10%
8 214,599,000 24,825,000 12%
93154\A2\JJB0427A.WB2

A streams only exist for turbidity and dissolved oxygen levels. The levels for both of these
parameters in the stream are within standards.
3.1.2.3 Land Use Evaluation
The total amount of impervious area within each land use across the entire watershed was also
computed. Results of the evaluation are summarized in Table 4, which includes the total area,
impervious area, and percent imperviousness of each land use. The total area shown in Table 4
is the total land use area that is currently shown on the Town's electronic land use mapping.
This total area does not correspond to zoning.
As shown in the table, the average level of imperviousness varies significantly with land use.
Commercial, industrial, mall, and highway land uses generally contain the highest percentage
of impervious surfaces (approximately 40 to 75 percent), while largely undeveloped land uses
such as vacant land, open space, utility transmission, and land trust/public easements contain
less than 3 percent impervious surfaces. Multi and single family residential land uses, public
and private facility, and commercial retail land uses contain intermediate levels of
imperviousness (approximately 18 to 30 percent).
3.1.2.4 Subwatershed Evaluation
For the purposes of this study, the Jordan Brook watershed was subdivided into 26
subwatersheds as shown in Figure 11. These subwatersheds were delineated from topographic
mapping provided by the Town for Jordan Brook tributaries, at major road crossings, and at
locations selected for hydrologic evaluation,
An evaluation was performed to determine the amount of impervious surface coverage within
each subwatershed using GIS data on impervious surfaces and the subwatershed boundaries
delineated for this project. The percent imperviousness of each subwatershed was calculated by
dividing the impervious area within a subwatershed by the total subwatershed area. Results of
the evaluation are summarized in Table 5. The impervious area values in Table 5 do not reflect
future land use conditions since it is not possible to accurately determine the amount of
impervious area that will be associated with future development.
The percentage of impervious area for individual subwatersheds ranges from approximately 20
to 30 percent in the most highly developed subwatersheds (1, AA, 1AB, [ABA, 2AAB, 2AAC,
and 2ABA) to less than 3 percent in subwatersheds 10 and 10A, which are located in a forested
area near the Jordan Brook headwaters. In general, subwatersheds with the highest percentage
93154\A2\EVM1203B.WPD
Corres. 9

Total Area Impervious Area Percent
Land Use (sq-ft) (sq-ft) Impervious
Cemetery 3,791,000 230,000 6%
Commercial Hospitality 42,000 20,000 48%
Commercial Office 42,000 17,000 40%
Commercial Retail 10,514,000 2,548,000 24%
Highway 3,633,000 1,396,000 38%
Industrial Manufacturing 3,537,000 1,294,000 37%
Industrial Warehouse 44,000 32,000 73%
Land Trust/Public Easement 686,000 19,000 3%
Mall 8,452,000 3,683,000 44%
Mixed Use 1,058,000 217,000 21%
Mobile Home 491,000 124,000 25%
Multi Family 3,597,000 713,000 20%
PA-490 42,713,000 327,000 <1%
Private Facilities 965,000 203,000 21%
Private Open Space 4,992,000 46,000 <1%
Public Facilities 8,176,000 2,094,000 26%
Public Land 18,057,000 271,000 2%
Public Utility 622,000 33,000 5%
Single Family 26,684,000 4,751,000 18%
Unknown 104,000 3,000 3%
Utility Transmission 5,425,000 50,000 <1%
Vacant. 59,143,000 1,316,000 2%
93154\A2\EVM1203B, WPD
Corres.

FO
Legend
——— Parcels Water Courses
C) Subwatersheds | Wetlands
=z Water Bodies
Scale
10) 2000 4000 6000 Feet
FUSS & O'NEILL INC. Consulling Engineers
146 HARTFORD ROAD, MANCHESTER, CONNECTICUT 06040
(860) 646-2469 FIGURE 11
www.FandO.com

Subwatershed Total Area Impervious Area Percent
(sq-ft) (sq-ft) Impervious
1 3,761,000 969,000 26%
1A 14,643,000 2,052,000 14%
1AA 1,981,000 659,000 33%
1AB 6,237,000 1,862,000 30%
1ABA 13,044,000 3,026,000 23%
2 8,679,000 981,000 11%
2A 15,605,000 2,837,000 18%
2ZAA 20,907,000 1,856,000 9%
QAAA 1,173,000 186,000 16%
2AAB 305,000 117,000 38%
2AAC 7,987,000 2,465,000 31%
2ZABA 926,000 262,000 28%
2B 11,258,000 1,466,000 13%
3 3,645,000 608,000 17%
4 24,721,000 930,000 4%
5 19,307,000 1,902,000 10%
SA. 2,093,000 282,000 13%
SAA 9,706,000 245,000 3%
SAAA 1,003,000 90,000 9%
6 2,542,000 380,000 15%
7 4,556,000 255,000 6%
7A 3,130,000 422,000 13%
8 8,113,000 468,000 6%
9 7,178,000 660,000 9%
10 7,987,000 26,000 <1%
10A 5,719,000 186,000 3%
Note:
1. Table excludes area of watershed located in New London
93154\A2\EVM0729A. WB2

wetland ecosystems within the Jordan Brook watershed. During this survey, available
information on watershed wetland systems was reviewed which included CTDEP aerial
photographs, town wetlands mapping, US Geological Survey (USGS) maps, and other CTDEP
maps and reports. In addition, watershed wetlands and watercourses were evaluated visually
at a number of stations. Based on this data, wetland functional values were estimated using
CTDEP Bulletin No. 9 as a guide. Note that although this evaluation provides a baseline
assessment of wetland resources throughout the watershed, it is not intended to supplant
requirements that developers provide additional detailed information about on-site wetlands as
required for a specific project.
3.2.1 Wetland Resources
For the purposes of this study, the long streams and wetland corridors within the watershed were
divided into five major segments and a name was assigned to each segment. The mainstem of
Jordan Brook was divided into three segments: Lower Jordan Brook (JL) from the dam at
Jordan Mill Park north to Route I-95; Central Jordan Brook (JC) from Routes I-95 to 1-395; and
Upper Jordan Brook (JU) from Route I-395 north to the vicinity of Lake Konomoc. Nevins
Brook (N) and an unnamed brook, hereafter designated East Brook (E), formed the fourth and
fifth segments. Each of the five segments was further subdivided into sections of mainstem
stream (M), tributaries (T), large swamps (S), or ponds (P). For example, a pond in the central
section of Jordan Brook would be designated JCP2 (J for Jordan Brook, C for central section,
P for pond and 2 as the pond number in the segment), A total of 41 wetlands within the
watershed, varying in size from 2 to 94 acres, were so numbered for the purposes of evaluation
during this study. The number of individual wetlands within the five main segments is shown
below. The location of these areas are shown in Appendix C.
NUMBER AND TYPE OF WETLANDS
Segment Mainstem Tributaries | Swamps Ponds Total
Sections
Jordan Lower 3 1 1 3 8
Jordan Center 2 6 2 1 11
Jordan Upper 1 1 1 2 5
Nevins Brook 2 3 2 2 9
East Brook 3 1 2 2 8
Total Bt 12 8 10 41
93154\A2\EVM1203B, WPD
Corres. 10

municipalities as a planning tool. It consists of a scientifically defensible numerical scoring
system which can be used to compare the relative value of all wetlands within the same
watershed. It is not intended to be used for the approval or rejection of specific development
proposals. However, the scores can be used to establish wetland policy, to identify particularly
high value wetlands, and to determine which wetlands may require special levels of protection
or warrant detailed study.
The CTDEP method identifies thirteen functional values of wetlands. Because of the large
number of individual wetlands in the Jordan Brook watershed, study resources were focused on
the four major functional values most important to the ecology of wetlands: Ecological
Integrity, Wildlife Habitat, Finfish Habitat and Visual/Esthetic Quality.
. Ecological Integrity is a measure of the overall health of a wetland and is based on such
factors as the quality of the inflow water, the type of wetland soils, the degree of
disturbance of soils and vegetation within and near the wetland, and the level of human
activity in the vicinity.
. The suitability of the wetland as Wildlife Habitat is based on size of the wetland, the
amount of open water, the number of different vegetation communities present, and the
percentage of wetland edge bordered by undisturbed upland habitat.
. The value of the wetland as Finfish Habitat is considered separately for streams and
ponds. Water quality is important, together with the size of the water body, the type of
aquatic and wetland vegetation, the characteristics of the bottom and the abundance of
cover available to fish.
. The Visual/Esthetic Quality of a wetland is based on the nature of the vegetation, the
degree of noise and odors present, the amount of visible open water, and the appearance
and use of the surrounding land. Although the visual quality of a wetland is not strictly
an ecological function, it is an important factor to residents in the area, and to people
using the wetland for such passive ecology-oriented recreation as hiking or bird
watching.
Functional values not included in the study were: Educational Potential, Water Based
Recreation, Flood Control, Groundwater Use Potential, Nutrient Retention/Sediment Trapping,
Shoreline Anchoring, Forestry Potential, Archaeological Potential, Urban Wetland Quality and
Noteworthiness.
93154\A2\EVM1203B.WPD
Corres, 11

The CTDEP method of evaluating the Flood Control function is based on the area of watershed
above a wetland compared to the area of watershed downstream at a potential flood damage
location. The Groundwater Potential of a wetland depends on whether the wetland is upstream
from a stratified drift aquifer and whether there are existing public or private wells. The quality
of the groundwater is also taken into account. Thus Flood Control and Groundwater Potential
are essentially based on the topography and hydrogeology of the area rather than on the ecology
of the wetlands, and these functions were not included in this evaluation. Flood Control issues
were considered, however, as part of the hydrologic evaluation of the watershed (Section 4.0),
and Groundwater Potential was considered as part of the aquifer evaluation (Section 6.1).
To evaluate the Nutrient Retention/Sediment Trapping function, the CTDEP method relies on
the average slope of the watershed above the wetland, the dominant land use, and potential
sources of nutrients or sediments within the watershed (i.e., cropland, pasture, livestock, septic
problems, areas of soil erosion, etc.). Consequently, the method does not consider the actual
ability of the wetland to remove pollutants, but rather considers the contribution of pollutants
from adjacent land uses. The Shoreline Anchoring function is based on the presence or absence
of banks and shorelines, on the width of adjoining wetlands, and on the density of vegetation
bordering the watercourse. The detailed field examination of the watershed and most of the
forty one wetlands required to complete the evaluation of these functions was beyond the scope
of this study.
The remaining four functional values were deemed not applicable to most of the Jordan Brook
watershed wetlands. Including such functions in the study would tend to reduce the mean scores
of otherwise valuable ecosystems, and to lower their evaluation. Forestry Potential is usually
limited to wetlands on large privately owned tracts of agricultural or wooded land. The
evaluation of Urban Water Quality requires that wetlands fall within a 4 mile radius of 90%
commercial, industrial, or transportation land use. Very few of the wetlands meet these criteria.
Criteria for Noteworthiness include the use of the wetland as a scientific research site, inclusion
in the Federal list of Natural Landmarks, and the presence of unique biological or geological
features. The Jordan Brook wetlands do not meet these criteria. Another criterion for
Noteworthiness is the presence of rare species habitats. The Connecticut Natural Diversity Data
Base was contacted to determine whether or not any Endangered, Threatened or Special
Concern Species are known to occur within the watershed. Their reply of April 26, 1998
indicated that one plant and one bird species have been reported somewhere in the area, but no
information was given concerning the exact location of these species (Appendix EF).
Information was also requested from the Connecticut State Archaeologist regarding possible
archaeological sites within the wetlands. The Public Archaeology Survey Team is responsible
for the development of Archaeological Potential information (Appendix E).
93154\A2\EVM1203B. WPD
Corres, 12

which is frequently used to indicate pollution, was measured in the larger streams and ponds
using a YSI Conductivity meter. A brief description of each wetland is given in Appendix C.
One of the limitations of the evaluation method is the problem of scale. Questions answered
from maps and photographs in the office are very broad and are based on characteristics of the
entire wetland and the watershed, On the other hand, questions answered by observations in the
field are very specific, and are based on conditions at the individual viewing locations. This
difference in scale is a disadvantage of the CTDEP method.
A total of thirty nine questions were answered for streams, thirty six questions for ponds, and
thirty questions for wooded or shrub swamps. The average of the scores, designated the
Functional Value Index (FVI), was calculated for each wetland. This index, the value of which
is always less than or equal to 1.0, can be used to compare the relative values of different
wetlands within the watershed. In addition, since larger wetlands are generally considered of
greater value than smaller systems, each FVI was multiplied by the acreage of its wetland to
yield a second index known as Wetland Value Units (WVU).
Because of the number of wetlands within the watershed, a total of over one thousand, six
hundred and fifty questions were answered to develop the wetland values. Specific methods
used to answer the questions are summarized in Appendix D. The individual scores for each
question and the average scores for each of the four functional values are also presented in
Appendix D.
3.2.3 Significant Resources
The results of the survey are summarized in Table 6. The table lists the wetlands and shows for
each wetland the area and conductivity, together with the average FV] and WVU scores. Where
a wetland was evaluated at two or more locations, the average value for all viewing locations
is shown. Mean FVI and WVU scores for the various wetlands can be compared using the
graphs in Appendix D.
In addition to the scores developed by the DEP method, Subjective Opinion scores are given for
each wetland. These scores, ranging from | to 4, are predicated on years of experience and
reflect the opinion of the biologist regarding the overall value of the wetland. The scores are
formed in response to such characteristics as vegetation diversity, the density of the shrub layer
and canopy, the presence or absence of invasive species, the prevalence of saturated soils or
standing water, etc. The purpose of the Subjective Opinion sc