Conservation Commission Meeting Agenda/Materials 109R and 131 Clark Lane Exhibit List (linked)

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FEB 08 2023
Planning & Development
Town of Waterford, cT j
APPLICATION REVIEW Part 1: PROPOSED RESIDENTIAL DEVELOPMENT
EAST OF
CLARK LANE, WATERFORD, CONNECTICUT
IN THE
UPPER FENGER BROOK WATERSHED
APPLICANT: Kingstown Properties, LLC OWNERS: L&M Archambault
PREPARED FOR THE WATERFORD CONSERVATION COMMISSION
BY "
Carya Ecological Services, LLC JANUARY 2023
Figure 2. Clark Lane,Waterford, CT.
Site vicinity and proposed activities.
Base map is a CTECO summer aerial
wx = a 4
. C-22-14
109R & 131 CLARK LANE
PUBLIC HEARING
EXHIBIT # 36

Carya Ecological Services, LLC
183 Guinevere Ridge
Cheshire, CT 06410
{203) 271-1949
sigrun.gadwa@sbcglobal.net
January 26, 2023
Conservation Commission, Town of Waterford
15 Rope Ferry Road
Waterford, Connecticut 06385 - 2886
ATTN: Chairman Dimmock and Environmental Planner, Maureen Fitzgerald
RE:
Application Review, Part 1: App. # C22-15. 47-Unit Residential Subdivision, including
affordable units; 141 Clark Lane. Owners: L & M Archambault; Applicant Kingstown
Properties, LLC
Carya Job No.; 23- WFD 3
Dear Commissioners:
Carya Ecological Services, LLC has conducted a preliminary review of the above-referenced
application by Kingston Properties, at the request of several property owners of abutting homes on
the east side of Clark Lane, including Arlene Sherman (119 Clark Lane).
1.0
INTRODUCTION
We have reviewed the following sources of information relevant to this application.
1,
www N
The most recent set of plans, dated 12-15-22, for this application, prepared by the firm of
Provost & Rovero, Inc., offering engineering, surveying, and land planning services. The 21-
sheet plan set is available for download on the Town of Waterford web site.
The Storm Drainage Report accompanying the plans, dated October 10, 2022
The wetland delineation report by soil scientist Joseph Theroux, dated 5-6-22.
The Wetland Functions and Values & Impact Analysis by J. Theroux, date 8-11-22.
Excerpts of the Technical literature on Stormceptor Pretreatment devices and on the
performance of biofiltration basins.
Performance Testing Results and design specification for biofiltration basins published by the
University of New Hampshire Stormwater Center (2009 and 2012, pp. 20 and 21 in both
reports). PDF’s may be downloaded from https:/Avww.unh.edu/unhse/pubs-specs-intfo .
Appendix A of the NY State DEC Stormwater Management Design Manual (Excerpts in
Attachment B)';

Town of Waterford, Conservation Commission
RE: Kingstown Properties’ proposed Residential Development east of Clark Lane
Jan 26, 2023
Page 2
8. Fenger Brook Watershed Management Study, New London and Waterford, 1996. Prepared for
Coastal Resources Management, Sea Grant Marine Advisory Program , New Haven, CT.
9, 2015 CTDEEP report on Fenger Brook (CT 2000-30-01) as an impaired portion of the
Southeast Shoreline Drainage Area (CT 2000).
10. CTDEEP Fisheries Data from 1993, 2001, and 2010.
Our goal was to evaluate the potential for significant adverse changes to this large, currently well-
buffered headwaters wetland system and to downstream regulated resources. These include Alewife
Cove, the easternmost cove on the Waterford Shoreline, sensitive to increased nutrient loading. *
Fenger Brook has overall impairment per the 2015 CTDEEP Report on Connecticut’s water resources,
but there is no breakdown as to the relative levels of impairment in different segments. Are hydrologic
changes reasonably likely to result from the proposed residential project: increased water in wetlands
bordering the southern portion by the stormwater discharge, and drier conditions bordering the narrow
northern portion? Will the stormwater management system, in particular the bioretention basin,
function as intended, preventing increased nutrient loading to the Fenger Brook riparian corridor and
the sensitive downstream estuary, Alewife Cove? Significance of impacts is closely tied to the
sensitivity and quality of the downgradient wetland resources, under existing conditions, and to
functional status.
To make this evaluation, we supplemented the information provided by the applicant with additional
natural resource data on the headwaters portion of Fenger Brook, to the extent feasible. We have not
yet found recent data on the health and nutrient status of Alewife Cove, key information that should
have been provided by the applicant. On Saturday, January 21", 2023, we conducted a field survey
of the site perimeter and downgradient wetland resources, and tested specific conductivity and salinity
at several locations, including a station just upstream (north) of Route 1. Local residents were also
questioned, Desktop Sources of Natural Resources Data on the site vicinity and the Fenger Brook
Watershed included the CTECO website, and the NRCS/USDA web soil survey. The Carya office
library has assorted studies and manuals on wetland buffers, stormwater management, functions and
values assessment methodology, and potential wetland stressors. The 2020 NY Stormwater
Management Design Manual and the University of New Hamshire Stormwater Center Provide
guidance on Bioretention Basin Design and Pollutant-loading data.
2.0 EXISTING CONDITIONS
Carya water quality testing results, shown in Table 1 in Attachment A, showed that upper Fenger
Brook does not currently have elevated levels of nutrients or salt; specific conductivity was only 146
uS/cm and salinity was 0.1 ppt at the station is just upstream of Route 1. Readings within interior
2 The 1996 Management Study of the Fenger Brook Watershed prepared by Sea Grant may be found in Attachment 3.. It
emphasies the importance and vulnerability of Alewife Cove.
Carya Ecological Services, LLC, Cheshire Connecticut January 26, 2023

Town of Waterford, Conservation Commission
RE: Kingstown Properties’ proposed Residential Development east of Clark Lane
Jan 26, 2023
Page 3
wetlands were also very low. One station did have elevated salinity and conductivity readings (4 ppt
and 549 uS/cm), in a small, west-flowing tributary to Fenger Brook, about 250 feet downgradient
(east) of the three-story apartment building just south of Clark Middle School. However, without
additional data on nutrient concentrations, the reason for the elevated specific conductivity is not
known. (Low electrical conductivity means unimpaired water, but conductivity can be elevated due
to a variety of dissolved constituents.) Note that the 2015 CTDEEP report did find impairment, but
did not specify locations, likely south of Route! in the lower watershed.
If upper Fenger Brook were significantly impacted by leachate from the closed New London landfill
(west of the subject site) the conductivity reading just north of Route 1 would have been much higher.
Perhaps this expected nutrient source has diminished since 2015. Otherwise, good water quality is not
surprising, in view of breadth of the protected forested open space in the headwaters of Fenger’s
Brook, about 2/3 mile wide near the subject site. Fortunately, the watershed of this brook does not
include the dense residential development along the Thames River and to the west of Clark Lane, as
shown in Figures 1 and 2.
Mr. Theroux provided good information on the hydrologic characteristics and functions of the very
long swath of wetlands immediately adjacent to the project (about 1/3 mile). These wetlands are
primarily groundwater fed, with seasonal saturation and flooding of depressions. Multiple small
drainageways flow towards Fenger Brook. He rated wildlife habitat, production export via food chain,
and ground water discharge as important functions; water quality was rated very good, consistent
with Carya water testing data. However Flood storage function was incorrectly rated as low, not
taking into account the irregular ground topography and multiple small and large depressions , that
trap and infiltrate precipitation, preventing flooding and downstream channel enlargement. Tree
transpiration also prevents flooding. Roots take up and transpire large volumes of surface water,
aerating the soil, and creating pore space for infiltration. Mr. Theroux did not assess the functions
and values of the wetland system as a whole as called for by the USACOE Highway Methodology,
and the other extant wetlands assessment methodologies. His assessment should have taken the New
London portion into account; it has more embedded pools and high-value upland islands, including
cliffs with den-caves suitable for bobcat. This top wetland predator is well-documented at this site.
Amphibians and crayfish are important foods for bobcat. Wildlife habitat was rated as a principal
wetland function, but the report did not mention the numerous forest pools, some of which are
expected to be productive vernal pools or the significance of the wetlands’ high ecological integrity.
The undeveloped land at the headwaters of Fenger Brook, north of Route 1, is an almost three-square
mile contiguous habitat block, a half mile to two third miles across.
We viewed the wetland from the west (Clark Lane back yards); from the South (from the entry Road
to Clark Middle School) and from the East. Habitat to the west of the site includes over 100 acres of
Carya Ecological Services, LLC, Cheshire Connecticut January 26, 2023

Town of Waterford, Conservation Commission
RE; Kingstown Properties’ proposed Residential Development east of Clark Lane
Jan 26, 2023
Page 4
forested ridges, scenic rock outcrops, cliffs, and wetlands, which can easily be accessed from Clark
Woods Park Road and a network of hiking trails. Undeveloped municipally owned land includes the
central and southern portion of New London’s 95-acre Clark Woods Park, which includes portions of
the subject wetland system. Accordingly it does have significant human use values: recreational,
educational and aesthetic value. Trails and vernal pools straddle the unmarked town line.
We also characterized and sampled several water quality parameters in the large forested wetland
south. of Clark Lane Middle School, which similar to the wetlands located downgradient of the
proposed high density, linear development of manufactured rental homes.
Photos of Bates Woods Park
CONCLUSION
It is our professional opinion that the omissions and concerns discussed orally in my presentation
today, based on the sources listed above in the footnotes to the materials reviewed, should be
addressed by the applicant before a permit is issued,
Respectfully submitted,
REMA ECOLOGICAL SERVICES, LLC
“ oo
Sigrun N. Gadwa, MS, PWS
Ecologist, Professional Wetland Scientist
Registered Soil Scientist
Carya Ecological Services, LLC, Cheshire Connecticut January 26, 2023

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Figure 1a. Fenger Brook Watershed (CT Basin 2000-30) showing dense
developed areas (pale) and CT-DEEP- permitted facilities with stormwater
‘discharges (yellow triangles). This is Figure 5 in an Appendix of the 2015
the SE Basin (CT 2000).
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_| Legend
4& — Stormwater Permits
MS4 Area
| Impaired Drainage Area(s)
impaired Waterbody(s)
. Surface Water
Major Road:
ot ‘Town Boundary
Permiis(s) within Fenger Brook Watershed with
Impairment to Habitat for Fish, Other Aquatic Life and Wildlife Created: CT DRRP, July 2012
Southeast Shoreline (CT2000) Summary
Page 11 of 16

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ATTACHMENT C. Stormwater Management Resources.
New York State Stormwater Management Design Manual Appendix A
Table A.2 Pollutant Concentrations from Source Areas
Constituent | TSS" TP’ TN’ | FColi’ | Cu! Pb’ Zn'
me/l mg/L mg/l et ug/l ug/l ug/l
Resid Roof 19 0.11 1.5 0.26 20 21 312
Comm Roof 9 0.14 2.1 li 7 17 256
Indust Roof 17 - - 5.8 62 43 1,390
C/R Parking 27 0.15 19 1.8 51 28 139
Packing 228 - - 2.7 34 85 224
Res Street 172 0.55 1.4 37 25 51 173
Comm Street 468 - - 12 73 170 450
Highway 51 - 2 - 22 80 80
Highway 142 0.32 3.0 - 54 400 329
Lawns 602 21 9.1 24 17 17 50
Landscaping 37 - - 94 94 29 263
Driveway 173 0.56 2.1 17 17 - 107
Gas Station 31 - - - 88 80 290
Auto Recycler 335 - - - 103 182 §20
Pee 124 - - - 148 290 | 1600
1: Claytor and Schueler (1996)
2: Average of Steuer et al. (1997), Bannerman (1993) and Waschbusch (2000)
3: Steuer et al. (1997)
A3 Attachment C: to Carya E.S. Review
of Proposed Clark Lane Residential
Development , January 2023.

New York State Stormwater Management Design Manual Appendix A
A.3_ Impervious Cover Data
The Simple Method uses different impervious cover values for separate land uses within a subwatershed.
Representative impervious cover data, are presented in Table A.3. These numbers are derived from a
recent study conducted by the Center for Watershed Protection under a grant from the U.S.
Environmental Protection Agency to update impervious cover estimates for a variety of land uses.
(Cappiella and Brown, 2001). In addition, some jurisdictions may have detailed impervious cover
information if they maintain a detailed land use/land cover GIS database.
Table A.3 Land Use and Impervious Cover Estimates
Land Use Category Mean Impervious Cover
Agriculture 2
Open Urban Land* 9
2 Acre Lot Residential 11
1 Acre Lot Residential 14
1/2 Acre Lot Residential 21
1/4Acre Lot Residential 28
1/8 Acre Lot Residential 33
Townhome Residential 41
Multifamily Residential 44
Institutional** 31-38%
Light Industrial 50-56%
Commercial 70-74%
* Open urban land includes developed park land, recreation arcas, golf
courses, and cemeteries.
** Institutional is defined as places of worship, schools, hospitals,
government offices, and police and fire stations
|A.4 Limitations of the Simple Method
The Simple Method should provide reasonable estimates of changes in pollutant export resulting from
urban development activities. However, several caveats should be kept in mind when applying this
method.
AS

New York State Stormwater Management Design Manual
A.5 SMP Pollutant Removal
Appendix A
The removal efficiencies of various SMP practices also help determine final annual pollutant loads. Table
A.4 provides estimates of the average pollutant removal efficiency of the five SMP categories.
Table A.4. Suggested Removal Rates for SMPs
TSS TP TN | Metals’ | Bacteria
Wet Ponds 80 50 (51) | 35 (33) 60 (62) 70
Stormwater Wetlands 80° (76) | 50 (49) 30 40 (42) 80 (78)
Filtering Practices 85 (86) | 60(59) | 40 G8) | 70(69) | 35 G7)
Infiltration Practices ‘ 90° (95) 70 50(51) | 90° (99) 90"
Water Quality Swales 85 (84) | 4039) | 50° (84) 70 0 (-25)°
1. Average of zinc and copper. Only zinc for infiltration
2. Many wetland practices in the database were poorly designed, and we consequently
adjusted sediment removal upward.
3. It is assumed that no practice is greater than 90% efficient.
4. Data inferred from sediment removal,
5. Actual data is based on only two highly performing practices.
6. Assume 0 rather than a negative removal.
Note: Data in parentheses represent median pollutant removal data reported in the National
Pollutant Removal Database - Revised Edition (Winer, 2000). These data were adjusted for
convenience and to reflect biases in the data.
These efficiencies represent ideal pollutant removal rates that cannot be achieved at all sites, or at a
watershed level. Typically, they need to be “discounted” to account for site constraints, and other factors
that reduce practice efficiency. For example, the removal rate should be adjusted to reflect the fraction of
runoff captured by a practice on an annual basis (90% if this guidance is followed). For more detail on
how to apply these discounts, consult Caraco (2001).
One particularly important consideration is how to account for practices applied in series (e.g., two ponds
applied in sequence). If the volume within the practices adds up to the total water quality volume, they
are assumed to act as a single practice with that volume. Otherwise, total pollutant removal should be
determined by the following equation:
R=L [((E;)+(- E)Ert(1-(E))+d- E)E)Est...]
Where:
R = Pollutant Removal (Ibs)
L= Annual Load from Simple Method (Ibs.)
E, = Efficiency of the ith practice in a series
Another adjustment can be made to these removals to account for loss of effectiveness and “irreducible
concentrations.” Evidence suggests that, at low concentrations, SMPs can no longer remove pollutants.
A7

New York State Stormwater Management Design Manual Appendix A
Steuer, J., W. Selbig, N. Hornewer, and J. Prey. 1997. “Sources of Contamination in an Urban Basin in
Marquette, Michigan and an Analysis of Concentrations, Loads, and Data Quality.” U.S. Geological
Survey, Water-Resources Investigations Report 97-4242.
Waschbusch. 2000, Sources of phosphorus in stormwater and street dirt from two urban residential basins
in Madison, Wisconsin, 1994-1995. In: National Conference on Tools for Urban Water Resource
Management and Protection. US EPA February 2000: pp. 15-55.
Winer, R. 2000. National Pollutant Removal Database - Revised Edition. Center for Watershed
Protection, Ellicott City, Maryland.
Attachment B. Part II. UNH Stormwater Managment Resources on
Biofiltration Basins(2009 and 2012 UNH Biennial Reports, pp 20 to 21in both)
Hard copies have been provided separately to the Conservation Commission.
NOTE: Both the 2009 and 2012 UNH Reports are available on line:
Performance Testing Results and design guidance for biofiltration
basins published by the University of New Hampshire Stormwater Center.
PDF’s may be downloaded from httos://www.unh.edu/unhsc/pubs-specs-info
and ac company the electronic submission of this report.
AG