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

SLRO
January 26, 2023
Ms. Maureen FitzGerald
Environmental Planner
Town of Waterford
15 Rope Ferry Road
Waterford, CT 06385
Re: Peer Review of Proposed Affordable Housing Development
131 and 109R Clark Lane
Waterford, Connecticut
SLR #141.13104.00015
Dear Ms. FitzGerald,
Per the request of the Wetland Office, SLR International Corporation (SLR) has performed a review of the
materials submitted in association with the site for the above-referenced project. The proposed plan is for
the development of 47 single-family homes with associated infrastructure. The following documents were
provided to us for our review:
e “Application for Inland Wetland/Watercourse Permit” dated December 6, 2022, stamped received
on December 6, 2022, by Planning and Development Town of Waterford, Connecticut
o “Sitewide Inland Wetland & Watercourse Activity Reporting Form”
¢ “Proposed Affordable Housing Development” prepared by Provost & Rovero, Inc., prepared for
Kingstown Properties, LLC, dated May 14, 2022, revised December 5, 2022, consisting of the
following sheets:
© Title Sheet, sheet 1 of 21, prepared by Provost & Rovero, Inc., prepared for Kingstown
Properties, LLC, dated May 14, 2022
o “PROPERTY SURVEY,” sheet 2 of 21, prepared by Provost & Rovero, Inc., prepared for
Kingstown Properties, LLC, dated May 14, 2022
o “OVERALL SITE PLAN,” sheet 3 of 21, prepared by Provost & Rovero, Inc., prepared for
Kingstown Properties, LLC, dated May 14, 2022
o “SITE PLAN No. 1,” sheet 4 of 21, prepared by Provost & Rovero, Inc., prepared for
Kingstown Properties, LLC, dated May 14, 2022
“SITE PLAN No. 2,” sheet 5 of 21, prepared by Provost & Rovero, Inc., prepared for
Kingstown Properties, LLC, dated May 14, 2022
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PUBLIC HEARING 01-26-23 @ 203-271-1773 @ sirconsulting.com
EXHIBIT #16
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January 26, 2023
Ms. Maureen FitzGerald
Page 2
SLR®
o “SITE PLAN No. 3,” sheet 6 of 21, prepared by Provost & Rovero, Inc., prepared for
Kingstown Properties, LLC, dated May 14, 2022
o “UTILITIES PLAN No. 1,” sheet 7 of 21, prepared by Provost & Rovero, Inc., prepared for
Kingstown Properties, LLC, dated May 14, 2022
o “UTILITIES PLAN No. 2,” sheet 8 of 21, prepared by Provost & Rovero, Inc., prepared for
Kingstown Properties, LLC, dated May 14, 2022
o “UTILITIES PLAN No. 3,” sheet 9 of 21, prepared by Provost & Rovero, Inc., prepared for
Kingstown Properties, LLC, dated May 14, 2022
o “LANDSCAPING PLAN No. 1,” sheet 10 of 21, prepared by Provost & Rovero, Inc., prepared
for Kingstown Properties, LLC, dated May 14, 2022
o “LANDSCAPING PLAN No. 2,” sheet 11 of 21, prepared by Provost & Rovero, Inc., prepared
for Kingstown Properties, LLC, dated May 14, 2022
o “LANDSCAPING PLAN No. 3,” sheet 12 of 21, prepared by Provost & Rovero, Inc., prepared
for Kingstown Properties, LLC, dated May 14, 2022
o “EROSION AND SEDIMENT CONTROL PLAN No. 1,” sheet 13 of 21, prepared by Provost &
Rovero, Inc., prepared for Kingstown Properties, LLC, dated May 14, 2022
o “EROSION AND SEDIMENT CONTROL PLAN No. 2,” sheet 14 of 21, prepared by Provost &
Rovero, Inc., prepared for Kingstown Properties, LLC, dated May 14, 2022
o “EROSION AND SEDIMENT CONTROL PLAN No. 3,” sheet 15 of 21, prepared by Provost &
Rovero, Inc., prepared for Kingstown Properties, LLC, dated May 14, 2022
o “DETAIL SHEET No. 1,” sheet 16 of 21, prepared by Provost & Rovero, Inc., prepared for
Kingstown Properties, LLC, dated May 14, 2022
o “DETAIL SHEET No. 2,” sheet 17 of 21, prepared by Provost & Rovero, Inc., prepared for
Kingstown Properties, LLC, dated May 14, 2022
o “DETAIL SHEET No. 3,” sheet 18 of 21, prepared by Provost & Rovero, Inc., prepared for
Kingstown Properties, LLC, dated May 14, 2022
o “DETAIL SHEET No. 4,” sheet 19 of 21, prepared by Provost & Rovero, Inc., prepared for
Kingstown Properties, LLC, dated May 14, 2022
o “DETAIL SHEET No. 5,” sheet 20 of 21, prepared by Provost & Rovero, Inc., prepared for
Kingstown Properties, LLC, dated May 14, 2022
o “SIGHTLINE DEMONSTRATION PLAN,” sheet 21 of 21, prepared by Provost & Rovero, Inc.,
prepared for Kingstown Properties, LLC, dated May 14, 2022
Abutting Property Owners List
“Alternatives Assessment” prepared by Provost & Rovero, Inc., prepared for Kingstown Properties,
LLC
“Storm Drainage Report” dated October 10, 2022, prepared by Provost & Rovero, Inc., prepared
for Kingstown Properties, LLC
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January 26, 2023
Ms. Maureen FitzGerald
Page 3 SLR
e “ALTERNATE SITE PLAN No. 1” prepared by Provost & Rovero, Inc., prepared for Freehold Real
Estate Management, dated November 30, 2021
e “ALTERNATE SITE PLAN No. 2”
e Letter from David J. Held, PE, LS, of Provost & Rovero, Inc., to Town of Waterford Conservation
Commission, dated December 5, 2022, regarding Kingstown Properties, LLC — 109R & 131 Clark
Lane — Waterford, CT P&R Job No. 213009
e Letter from Joseph R. Theroux, Certified Soil Scientist, to Mr. David Held, dated December 6, 2022,
regarding Wetland Delineation, Archambault Property, Clark Lane, Waterford, CT
e Letter from Joseph R. Theroux, Certified Soil Scientist, to Mr. Held, dated August 11, 2022,
regarding Wetland function & value and impact assessment report for the proposed site
development for the Archambault property, 109R and 131 Clark Lane, Waterford, Connecticut
Engineering Review Comments
The following comments and observations are made based on the review of the information provided by
the applicant. Comments pertain specifically to the Stormwater Management Plan, Erosion and Sediment
Control Plan, and consistency with the Town of Waterford's Wetland Regulations and applicable state
guidelines. Comments regarding site plan components that may not typically have a nexus with wetlands
are included because much of the site falls within the regulated upland review areas and resulting revisions
may cause changes to regulated activities. Please note this review did not consider all the requirements
and standards of the Waterford Zoning Regulations as they relate to the site plans.
1. The test pits performed within the sediment basin/stormwater management area showed
mottling (seasonal high groundwater) as shallow as 22” and groundwater at 45”. The applicant’s
engineer will need to provide dewatering measures for the sediment basin in between rainfall
events due to the limited potential of stormwater infiltration and the high likelihood of
groundwater present within the sediment basin. The sizing calculations for the temporary
sediment basin rely on the volume to be provided to the basin bottom.
2. We recommend that the upland review area (URA) line is displayed on all site plan sheets.
3. While not specifically a wetland-related issue, there are no sidewalks or walkways shown to the
houses, internally in the development, or out to Clark Lane. These site amenities should be
considered so that any stormwater impacts may be accounted for.
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January 26, 2023
Ms. Maureen FitzGerald
Page 4 S LRO
4. We recommend that the applicant consider temporary construction fence be placed along
portions of the northern, western, and southern property lines to serve as barrier between existing
homes and the project site.
5. Werecommend that the applicant’s engineer consider small drainage inlets to the rear of Units 27
through 47 due to the generally level grading and potential for localized ponding. Alternatively,
the plans should include more detailed grading to demonstrate flow paths behind these units.
6. An access path to the bioretention basin should be provided for future maintenance purposes.
7. Based on the test pits performed within the bioretention basin and detention basin, dewatering
during construction in areas outside of the stormwater basin may be needed. Additional
information and details on the potential dewatering operations should be provided.
8. The applicant’s engineer should comment on the suitability and effectiveness of the bioretention
basin given the shallow water table and likelihood that a majority of the basin would be into the
groundwater. The 2004 Connecticut Water Quality Manual recommends that there is at least
several feet of separation between the bottom of the filter and the seasonally high groundwater
table.
9. The applicant’s engineer should consider raising the elevation of the basin to reduce the depth of
excavation into the water table.
10. We recommend that the inverts of the outlet pipes for DMH 114 and CB 109 are dropped to limit
surcharging of the 6” polyvinyl chloride underdrains.
11. Immediately adjacent to the rear of Units 1 through 16, a proposed 2-foot horizontal to 1-foot
vertical slope (2:1) is depicted. This area behind the units will have limited to no function without
small retaining walls or other grading configurations between the units and the property line.
12. An inlet protection detail is shown, but no locations or callouts for inlet protection are displayed
on the Erosion & Sedimentation Control Plans.
13. The finished floor elevations of the proposed units should be provided.
14. The applicant should provide additional information regarding trash and recycling disposal for the
development.
15. The applicant’s engineer should confirm whether any of the existing upgradient homes are served
by a septic system.
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January 26, 2023
Ms. Maureen FitzGerald
Page 5 SLR@
16. We recommend that a roadway profile or spot grades are provided to clarify the high and low
spots of the roadway.
17. The drainage analysis utilizes fair condition for the land cover types — grass cover, woods, and
woods/grass combination — for a significant portion of the existing and proposed watersheds. We
recommend that the applicant review whether the fair condition designation is most appropriate
instead of good condition given the existing and proposed land coverage.
18. The applicant’s engineer should confirm that the roof drains for the homes are included in the pipe
computations. There are notes that the roof drains are to connect to the drainage system,
although the plans should depict how they are to connect to the drainage system.
19. We recommend that the pipe capacity be included in the pipe computations in the Storm Drainage
Report.
20. The 24” detention basin outlet pipe lacks the capacity to transmit the discharge from the basin for
the 100-year storm.
21. The Storm Drainage Report states that the flow velocity from the level spreader for the 100-year
storm is 1.78 feet per second; we recommend that the supporting design computations be
provided.
22. Watersheds P-1 and P-2 are mislabeled in the stormwater routing diagram in the Storm Drainage
Report.
23. The length, slope, and invert of the primary outlet (24” round culvert) for Pond Report 6P:
Detention Basin in the Storm Drainage Report does not match the site plans.
Wetland Science Review Comments
The 16.06-acre site is comprised of two parcels, one 4.33 acres and the other 11.73 acres. The site is L-
shaped with a narrow piece of land approximately 180 feet wide, trending north/south and paralleling
Clark Lane, and a wider area extending east at the southern portion of the property behind the Clark Lane
Middle School. Surface water drains to the southeast extent of the site and flows south via Fenger Brook
for approximately 1.4 miles, then west toward Jordan Mill Pond via an unnamed watercourse for
approximately 1.3 miles. From Jordan Mill Pond, Jordan Brook flows south for approximately 2 miles to its
confluence with Long Island Sound. The confluence with Long Island Sound is approximately 3 miles south
of the subject property. The property is currently undeveloped and wooded, although early successional
vegetation and stone walls suggest previous use as farmland or pasture.
Wetland systems occupy approximately 6 acres of the 16-acre parcel, and these systems are comprised of
palustrine broad-leaved deciduous forest and scrub-shrub wetlands. In addition to the onsite wetlands, a
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January 26, 2023
Ms. Maureen FitzGerald
rages SLR®
forested palustrine riparian wetland associated with Fenger Brook abuts the site to the east. Although off
site, the upland review area to this wetland extends onto the subject property. The 500-year floodplain to
Fenger Brook is located off site to the southeast. The property directly abuts the city of New London. The
wetland delineation report and wetland impact assessment submitted with the application detail the
wetland as contributing to most wetland functions and values and being supported by poorly drained
glacial till soils, which is consistent with Natural Resource Conservation Service (NRCS) mapping for the
property.
Please note that redundant comments of the engineering comments have been omitted for brevity:
1. Wetland boundary — The wetland system extends off site to the east. Some of the offsite wetland
boundary is noted. However, the line is not contiguous. The wetland boundary located east of the
proposed detention basin conflicts between onsite and offsite areas. Please correct the wetland
boundary to understand the scope of work proposed within regulated areas.
2. The wetland impact assessment documents habitat for reptiles and amphibians but does not
provide specifics. Was vernal pool activity noted in the wetland complex during the May 2021
delineation or March 2022 impact assessment fieldwork? Given the potential for turtle habitat, a
conservation protection plan is warranted during construction. These conservation measures
involve exclusionary fencing, wildlife sweeps, and contractor education.
3. If vernal pool activity was noted in the wetland complex, SLR recommends incorporating design
measures to prevent the use of the stormwater basin as a “decoy pool.”
4. A native planting plan for the proposed detention basin and biorentention basin would increase
the ecological integrity of this area and bolster the buffer between the proposed housing and
wetland system.
5. The proposed detention basin will lie at elevation 90.0 NAVD, which is the approximate wetland
elevation. Maximizing the benefits of this hydrology to create a wetland habitat in the basin would
improve the water quality benefits through bioassimilation as well as provide aesthetic and habitat
values.
6. The level spreader outlet from the basin directly abuts the wetland boundary. It will be difficult to
construct this feature without encroaching in the wetland. SLR recommends the consideration of
a minimum of a 10’ buffer here to avoid direct impacts.
7. Permanent demarcation of the wetland boundary and conservation areas with signage is
recommended. The proposed houses are near the wetland boundary, and this nexus often
presents conflict through encroachment, vegetation clearing, dumping, etc. if not properly
managed with signage and outreach.
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January 26, 2023
Ms. Maureen FitzGerald
Page 7 SLR®
8. Undisturbed wetland buffers are noted on the permit application as a mitigating measure. It is
unclear if that is true without a full depiction of the wetland boundary off site and the clear
depiction of the upland review area on each plan sheet. Please also note that permanent features
of the stormwater management system are located directly on the wetland boundary in the
southeastern portion of the property.
9. Test pits provided in the plan set detail a water table within 2 feet of the ground surface in three
of the four test pits. Given the excavation of this area, to create the temporary and permanent
basin, SLR recommends a discussion on measures to manage water in this area over the short-
term construction phase, related to potential issues with sedimentation and erosion control, and
long-term with respect to water quality.
10. Please provide the methods for snow removal and products that will be used to deice the
impervious surfaces.
11. Are the dwellings going to be managed as apartments or will they be individually owned?
Education on nexus to protected wetland resources will assist on minimizing conflicts with
stewardship in the short and long term.
12. Of the 16 acres in the project area, 8 acres will be developed and 8 acres will be provided as
conservation easement. Information on how this easement will be held will allow direction on
property stewardship. Management of invasive vines on canopy trees would assist in maintaining
woodland canopy in undisturbed portions of the site.
13. A walking trail is proposed around the detention and biorentention basins, but was there
consideration of increasing the trail to the southeastern portion of the site? Wetlands are a factor
here, but increasing the recreational and educational value of the wetland may benefit the
community. Given the depth of the proposed basin, a walking path around the perimeter may
present safety issues.
Thank you for the opportunity to assist you.
Sincerely,
SLR International Corporation
Wa Why 2 ~~
Ryah McEvoy, PE Megan B. Raymond, MS, PWS, CFM
Principal Civil Engineer Principal Scientist, Wetlands & Waterways Lead
13104.00015.j2623.Itr.docx
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