Conservation Commission Agenda (linked)

April 23, 2024
Joe Wren, PE
Principal 
Indigo Land Design, LLC
40 Elm Street, 2nd Floor 
Re:  
430 Mohegan Avenue Parkway
 
23B Old Norwich Rd 
Waterford CT
CLA –7572
Dear Mr. Wren: 
At your request, CLA Engineers delineated inland wetlands on the referenced parcel 
according to the State of Connecticut statutory definition as described in C.G.S. Section 
22a. CLA conducted fieldwork in February, March and April of 2024 and delineated the 
inland wetland boundary with sequentially numbered pink flagging tape. This letter 
documents the wetland delineation and the soils encountered on the site. 
Site Setting
The site is currently undeveloped except for a sanitary sewer that runs along the northerly 
side from Roberts Court to Mohegan Avenue Parkway. The vegetation is in an early stage 
of old field succession and dominant vegetation includes multiflora rose (Rosa multiflora) 
barberry (Berberis thumbergii) reaspberry (Rubus spp.) Where trees occur, they include 
red maple (Acer rubrum) tree of heaven (Ailanthus altissma) hickories (Carya spp.) and 
black walnut (Juglans nigra).   
The current land use surrounding the site is predominantly residential to the west, north 
and east.  Connecticut College is located to the south.
The topography of the site features moderate to gentle hillslopes with high elevations of 
approximately 168’ NAVD on the southwestern side of the site down to elevation 
approximately118’ in a bowl like depression on the eastern edge of the site. Surface water 
flows offsite to east under Mohegan Avenue Parkway via a culvert.  The water eventually 
flows into Mamacoke Cove.  Fill, in the form of boulders, was historically placed along
upland edge of wetland and subsurface flow emanates from boulder fill area.  
CLAEngineers, Inc. 
Civil
  Structural
Survey
317 MAIN STREET
NORWICH, CT 06360
(860) 886-1966
(860) 886-9165 FAX

 
 
 
 
Soils
 
Southern New England was overlain by glacial ice as recently as 12,000-15,000 years ago
during the Wisconsin glaciation.  The materials that the glaciers deposited over top the 
local bedrock determine the surficial geology of the region and of the site.  These glacial 
deposits are generally divided into three categories: glacial till (un-stratified sand, silt and 
rock), glaciofluvial (water sorted, stratified sand and gravel), and glaciolacustrine 
(stratified sand, silt and clay that settled out in lakebeds).  The original type of glacial 
deposit present on the site is glacial till. This finding is based on on-site–observations and 
the NRCS mapping (attached) that shows the soil series mapped as (51) Sutton, (61) 
Canton and Charlton and (84) Paxton and Montauk. 
 
The soils on the site have been re-graded for the existing site development within the sewer 
easement.  The slopes down to the wetlands reflect past grading and filling. 
 
Table 1 is a sumary table of the soils found on the site.  Appendix A provides additional 
soil data 
 
Table 1 - Soil Types and Properties at the 430 Mohegan Avenue Parkway Site 
Soil Series 
Parent Material 
Drainage Class
Texture/Characteristics
3  Ridgebury, 
Leicester, 
Whitman*  
Glacial till with 
dense layer
Somewhat Poorly 
to very poorly 
drained  
Sandy loam 
51 Sutton 
Glacial till
Moderately well 
drained
Sandy loam 
61 Canton and 
Charlton 
Glacial till
Well Drained
Sandy loam 
84 Paxton and 
Montauk 
Glacial till
Well Drained
Sandy Loam 
* Wetland soil types on site, not mapped by NRCS  
 
The Ridgebury, Leicester and Whitman  series consists of very deep, somewhat poorly to
poorly drained soils formed in lodgment till derived mainly from granite, gneiss and/or 

 
 
 
schist. They are commonly shallow to a densic contact. They are nearly level to gently 
sloping soils in depressions in uplands.
The Sutton series consists of very deep, moderately well drained loamy soils formed in 
melt-out till. They are nearly level to strongly sloping soils on hills, low ridges, and 
ground moraines, typically on footslopes, lower backslopes and in slight depressions.
 
The Canton and Charlton series consists of very deep, well drained soils formed in a 
loamy mantle underlain by sandy till. They are on nearly level to very steep moraines, 
hills, and ridges. 
 
The Paxton and Montauk series consists of well drained loamy soils formed in lodgment 
till. The soils are very deep to bedrock and moderately deep to a densic contact. They are 
nearly level to steep soils on hills, drumlins, till plains, and ground moraines. (Source: 
NRCS https://soilseries.sc.egov.usda.gov)
 
 
Wetland Description 
 
This site has one wooded wetland system that system that continues to the east. Citation: 
(https://fwsprimary.wim.usgs.gov/wetlands/apps/wetlands-mapper/.) 
I. 
Classification code: PFO1E 
System Palustrine (P) : The Palustrine System includes all nontidal wetlands dominated 
by trees, shrubs, persistent emergents, emergent mosses or lichens, and all such wetlands 
that occur in tidal areas where salinity due to ocean-derived salts is below 0.5 ppt. It also 
includes wetlands lacking such vegetation, but with all of the following four 
characteristics: (1) area less than 8 ha (20 acres); (2) active wave-formed or bedrock 
shoreline features lacking; (3) water depth in the deepest part of basin less than 2.5 m 
(8.2 ft) at low water; and (4) salinity due to ocean-derived salts less than 0.5 ppt.  
Class Forested (FO) : Characterized by woody vegetation that is 6 m tall or taller.  
Subclass Broad-Leaved Deciduous (1) : Woody angiosperms (trees or shrubs) with 
relatively wide, flat leaves that are shed during the cold or dry season; e.g., black ash 
(Fraxinus nigra).  
Water Regime Seasonally Flooded/Saturated (E) : Surface water is present for 
extended periods (generally for more than a month) during the growing season, but is 
absent by the end of the season in most years. When surface water is absent, the substrate 
typically remains saturated at or near the surface.  
 
The on-site wetland has predominantly of red maple trees in the canopy.  The understory
is a dense tangle of multiflora rose and Japanese barberry. Also present were jewelweed
(Impatiens capensis) and skunk cabbage (Symplocarpus foetidus).
 

Vernal Pool Investigation 
CLA conducted on-site investigations of the wetland on March 15, 2024 and April 8 
2024. These dates coincided with site visits to other, known vernal pools in coastal 
southeastern Connecticut, which had wood frog and spotted salamander egg masses 
present. No wood frog or spotted salamander egg masses were found at the site, nor was 
there any other evidence of reproduction of vernal pool species.  The maximum depth of 
water present in the wetland was six inches. Given this hydrology, it is not surprising that 
the wetland does not support vernal pool species.  
Potential for Wetland Impacts
CLA understands that the proposed development, as designed by Indigo land Design LLC,
has the following characteristics:
A 75-foot vegetated buffer will be maintained around the inland wetland. 
The stormwater treatment system is designed to meet the CTDEEP 2004 Manual 
as revised to 2024. 
The Erosion and Sedimentation controls have been designed to be consistent with
the CTDEEP 2002 Manual as revised to 2024. 
Given that lack of direct wetland impacts and the three factors mentioned above, CLA 
believes that the project can be constructed without adverse impacts to inland wetlands. 
Please contact me if you have any questions.
 
 
 
 
 
Sincerely,
Robert C. Russo CSS 

 
 
 
 
 
 
 
Appendix A  
Soils Data