HomeMy WebLinkAboutWetland Report
July 15, 2025
Town of Montville Inland Wetlands Commission ATTN: Douglas K. Brush, Chair Montville Town Hall
310 Norwich-New London Turnpike
Uncasville, CT 06382 Re: Ebdath Chowdhoury Residential development
Glen Road
Montville, CT CLA-8020 Dear Mr. Brush:
On behalf of Ebdath Chowdhoury, CLA Engineers has performed a delineation and functional evaluation of the inland wetlands at the referenced site and assessed the site to provide a basis for determining the potential for impacts associated with the proposed development of this parcel. Details of the proposed development of this parcel are presented on the site plans.
The inland wetland boundary was delineated by R. Russo (CLA Engineers) in January of 2025. The wetland boundary and proposed development are shown on the plans prepared by CLA Engineers dated 5/30/2025. These data were augmented with additional online information from CTDEEP, USFWS, USGS, and the Town of Montville GIS.
Site Setting This site consists of mixed forest and wetland area which is located right at the end of Glen Road. There is a small stream that flows through the wetlands onsite which is a tributary to Stony
Brook Stream. The wetland is divided by Connecticut Route 2A with culverts allowing water
passage to the wetland on the other side. This surrounding area is relatively developed, consisting primarily of residential homes. This site is zoned as residential (R20) along with the other properties surrounding it.
CLA Engineers, Inc.
Civil Structural Survey
317 MAIN STREET NORWICH, CT 06360 (860) 886-1966 (860) 886-9165 FAX
Soils The upland soils mapped by NRCS are listed in the table below. There are hydric soils mapped
on the property by NRCS. These include the Raypol and Scarboro Series. Additional descriptive
details are provided in an NRCS soil report included as Appendix A.
Table 1 - Soil Types and Properties at the Glen Road Site
Soil Series Parent Material Drainage Class Texture/Characteristics
Raypol Coarse loamy eolian deposits over sand and gravel glaciofluvial
deposits
Poorly drained Silt loam to stratified gravely coarse sand to loamy fine sand
Scarboro Sandy glaciofluvial deposits Very poorly drained Muck to gravelly sand
Agawam Coarse loamy eolian deposits over sand and gravel glaciofluvial
deposits
Well drained Fine sandy loam to loamy sand
Udorthents-Urban Complex Human transported material Well drained Loam to very gravelly sandy loam
Ninigret Coarse loamy eolian deposits over sand and gravel glaciofluvial deposits
Moderately well drained Fine sandy loam to loamy sand
Tisbury Coarse silty eolian deposits over sand and gravel
glaciofluvial
deposits
Moderately well drained Silt loam to extremely gravelly sand
The Raypol series consists of poorly drained soils formed in eolian deposits overlaying
glaciofluvial material. They are nearly level sloping soils formed in drainageways. The Scarboro
series are very poorly drained soils formed in glaciofluvial deposits. They are nearly level soils found in drainageways depressions, outwash deltas, and outwash terraces. The Agawam series are well drained soils formed in eolian deposits overlaying glaciofluvial material. They are gently sloping soils found in outwash terraces. The Udorthents-Urban Complex series contains
well drained soils formed by human transported materials. They are nearly level to steep sloping soils and can be found in areas in or near human disturbance. The Ninigret series are moderately well drained soils formed in eolian deposits overlaying glaciofluvial material. They are nearly level soils commonly found in outwash terraces. The Tisbury series contains moderately well
drained soils formed in silty eolian deposits overlaying glaciofluvial material. They are nearly level sloping soils which can be found in outwash terraces, deltas, outwash plains, and valley
trains.
Wetland Characteristics Classification The National Wetlands Inventory
(NWI https://fwsprimary.wim.usgs.gov/wetlands/apps/wetlands-mapper/) does show the onsite
wetland and it is classified as PFO1E. A description of this wetland group can be found below: 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.
Wetland hydrology There is one regulated area on the southern part of the project site where wetland is present. The
wetland has many areas of pooling water and is underlain by sandy soils. This wetland discharges
the water into a watercourse that starts right near CT-Route 2A and flows under through a culvert to another wetland. This unnamed watercourse is a tributary to Stony Brook Stream which drains into the Thames River and Long Island Sound.
Factors important to functional assessment
The following observations are important to the functional assessment and are listed here to provide context to the later discussion of functions and values.
1. Connecticut protected species are not known to be present on the site per the December
2024 update of the CTDEEP NDDB. See Appendix C. 2. The local zoning is Residential (R20) per the Town GIS, and the surrounding parcels appear to be single-family residences.
3. The wetland has eolian deposits over glaciofluvial material along with glaciofluvial deposits around its edges per available online mapping. Detailed soil mapping from the
U.S. Web Soil Survey is included within Appendix A.
4. The streams below the wetland onsite have good quality habitat for fish populations, including wild brook trout. Data collected by CTDEEP can be viewed in Appendix E. 5. This wetland is used for a variety of different species including coyotes, red-tailed hawks, red-winged black birds, and deer. See Appendix D for a full list of species.
6. There is multiple different wetland communities present onsite. Principal functions The functional assessment was conducted using the USCAE Highway Methodology
(https://www.nae.usace.army.mil/Portals/74/docs/regulatory/Forms/HighwaySupplement6Apr20
15.pdf). The assessment is included as Appendix B and it revealed that the wetland onsite with a small intermittent watercourse running through it has the following Principal functions: 1. Groundwater Recharge/Discharge: Wetland is underlain and borders sandy and
gravelly soils and appears to discharge water into the unnamed watercourse which feeds
into Stony Brook Stream. 2. Floodflow Alteration: This wetland is very flat, contains dense vegetation, has hydric soil and has standing water within it. CLA believes that this wetland would be able to store a lot of water during a significant storm event.
3. Sediment/Toxicant Retention: This wetland has multiple residential houses near its
edge with moderate sized laws. Given that this wetland is broad, has organic and fine sandy soils, and can hold water for extended periods of time, CLA believes this wetland can retain toxicants. 4. Nutrient Removal: The wetland onsite is densely vegetated and has multiple different
wetland communities within it which would allow for the attenuation of excess nutrients
from fertilizer runoff from nearby homes. 5. Wildlife Habitat: CLA noticed deer tracks and scat, viewed red-tailed hawks, and saw a coyote using this wetland during the site visit on July 1st, 2025.
Potential for Impacts As shown on the project plans, the following activities are planned. 1. Construction of a 5-bedroom home with a sunroom, 2 porches and a walkway
2. Installation of a 1,500-gal concrete septic tank with 2 D-boxes and leach fields
3. Construction of a retaining wall 4. Installation of a well 5. Installation of a curtain drain with 6” pvc attached to it. 6. Installation of a drainage basin with a 12” HDPE pipe which leads to a rip-rap drainage
outlet.
7. Construction of a footing drain and a rip-rap footing drain outlet
Based on the plans, there will be 4200 square feet of disturbed wetland area due to the following:
1. Construction of the driveway 2. Installation of modified rip-rap inlet on the side of the driveways with a round 12” concrete pipe under feeding to a rip-rap outlet.
The proposed activities outlined above may impact the regulated resource’s principal functions in
the following ways: 1. Groundwater Recharge/Discharge: With the installation the driveway over existing wetland, the groundwater recharge will be slightly impacted as there is less land available
for this function. The plan does include some disconnection of impervious surface by
including a driveway circle of vegetated areas for runoff to infiltrate. The plans also keep a vegetated buffer between the proposed home and the wetland area. 2. Floodflow Alteration: The part of the driveway in the wetland with drainage pipes going under will lead to more direct runoff going into the wetland. Near the house, the runoff is
being directed to riprap drainage areas at the edge and just within the 50’ upland review
area. There is a natural vegetated buffer that will remain between the wetland and proposed drainage point to promote infiltration. The plans to add flood water storage capacity in an upland area which will offset the loss of flood storage from filled wetlands. 3. Sediment/Toxicant Retention: The driveway constructed in the wetland will remove
vegetation and decrease the potential for sediment and toxicant retention from
surrounding runoff and push this function to occur further in the wetland. To mitigate this during construction, silt fence will be installed at the edge of the driveway and a proposed riprap outlet to catch any excess sediments during construction. Near the house outside of the wetland, silt fence will still be installed along the vegetated buffer to prevent excess
sediments from accumulating in the wetland
4. Nutrient Removal: The driveway proposed in the wetland will reduce the amount of native vegetation and add impervious area which will reduce some of the wetland’s ability to attenuate nutrients. However, appropriate sediment and erosion control measures will be implemented to reduce excess nutrients from the project entering the
wetland. While the house outside of the wetland will have a lawn that could be a source
of excess nutrients, there will still be a vegetated buffer to intercept and attenuate it. 5. Wildlife Habitat: With the proposed wetland disturbance from the driveway, some wetland habitat will be lost, providing less food and shelter for wildlife. The upper portion of the site where the home is located should not have any effect on this function given the
proper erosion and sediment control measures and due to there being a vegetative buffer
present.
Alternatives Considered When designing the driveway, multiple different options were considered on how to connect the planned house to Glen Road. Regardless of the different options, wetland disturbance on this site
is inevitable. Due to this, the path that would have the least amount of disturbance on the wetlands onsite was chosen.
Summary The site plan does include impacts on the functionality of the onsite wetlands due to there being 4200 square feet of wetland disturbance for the installation of the driveway. There will be
slightly more stormwater runoff entering the wetlands which could potentially carry slightly
more nutrients and sediments. The clearing of the wetland for the driveway would also reduce some vegetation, food sources, and habitat for wildlife species. However, if proper sediment and erosion control measures are installed and inspected regularly and the vegetated buffer outside of the wetland is maintained, these impacts will be reduced to a minimal level.
Sincerely, Robert C. Russo
Soil Scientist, CLA Engineers
Norwich, CT
Appendix A: Soil Maps
From USGS Web Soil Survey
Appendix B: Army Corps Wetland Assessment
Sheets
Appendix C: Natural Diversity Data Base Map
Town of Montville, CT
Appendix D: Species List
Plant Species:
Cinnamon fern (Osmundastrum cinnamomeum)
American beech (Fagus grandifolia)
Japanese barberry (Berberis thunbergii)
Wood fern (Dryopteris carthusiana)
Spicebush (Lindera benzoin)
American hornbeam (Carpinus caroliniana)
Broom forkmoss (Dicranum scoparium)
Wrinkleleaf goldenrod (Solidago rugosa)
Skunk cabbage (Symplocarpus foetidus)
Sweet pepperbush (Clethra alnifolia)
Devil’s beggarticks (Bidens frondosa)
False nettle (Boehmeria cylindrica)
Royal fern (Osmunda regalis)
Common reed (Phragmites australis)
Jack-in-the-pulpit (Arisaema triphyllum)
Blue violet (Viola sororia)
False brome (Brachypodium sylvaticum)
Sensitive fern (Onoclea sensibilis)
Northern dewberry (Rubus flagellaris)
Black birch (Betula lenta)
American climacium moss (Climacium americanum)
Red oak (Quercus rubra)
Red maple (Acer rubrum)
Brome-like sedge (Carex bromoides)
Shallow sedge (Carex lurida)
American water plantain (Alisma subcordatum)
White pine (Pinus strobus)
Pincushion moss (Leucobryum glaucum)
Multiflora rose (Rosa multiflora)
Greenbriar (Smilax rotundifolia)
Bladder sedge (Carex intumescens)
Eastern hemlock (Tsuga canadensis)
Highbush blueberry (Vaccinium corymbosum)
Wineberry (Rubus phoenicolasius)
Virginia creeper (Parthenocissus quinquefolia)
Princess pine (Dendrolycopodium obscurum)
Animals confirmed:
Wood frog (Lithobates sylvaticus)
Red-tailed hawk (Buteo jamaicenis)
White-tailed deer (Odocoileus virginianus)
Red-winged blackbird (Agelaius phoeniceus)
Coyote (Canis latrans)
Possible species:
Spotted salamander (Ambystoma maculatum)
Red-backed salamander (Plethodon cinerus)
Ringneck snake (Diadophis punctatus)
Appendix E: CT DEEP Fish Community Data