HomeMy WebLinkAboutIWA Dart Hill Rd reconstruction 10-2023M E M O R A N D U M
To: South Windsor Inland Wetland/Conservation Commission.
From: Jeffrey H. Folger – Environmental Planner/Conservation Officer
Date: October 18, 2023
Re: Appl. #23-45W Review of the proposed Dart Hill Rd drainage improvements. Plans dated 09/01/23.
The project is to add runoff protection measures to an existing culverted watercourse crossing on Dart Hill Rd. This will involve the removal of two existing road leak-offs on the northern
and southern side of the crossing, and the placement of a rip-rap plunge pool on the southern side of the crossing. Regulated activities include the filling and grading within the
100-foot upland review area (URA) and direct impact to the wetland/watercourse for the installation of a plunge pool. Proposed disturbance within the URA is estimated at approximately
.40 acres (17,500 sqft). Direct disturbance with regulated areas is estimated at approximately .002 acres (100 sqft).
Site: The site is located in the Hockanum River watershed.
The regulated areas consist of a perennial watercourse and adjacent wetland areas orientated north to south. The watercourse drains the wetland system that extends northward to the
Town line through the Debbie Drive and Spinners Run neighborhoods. There is currently a five-foot wide box culvert present. This culvert is not proposed to be altered. Upstream from
the culvert, the channel is armored with rip-rap for approximately 30 feet. Downstream from the culvert, the channel is concrete lined for approximately 20 feet. The stream channel
width in this area is approximately 3-4 feet. The watercourse continues to the east toward the Hockanum River.
Impacts:
Short Term: Soils on the site where the work is to occur would be characterized as Urban complex due to the stony fill and concrete. Minimal impacts of sedimentation are expected.
The road bed work plan includes an erosion protection plan to contain sediments during construction. Perimeter silt fencing is proposed to be installed along the limit of
disturbance. Silt sacs are to be installed within existing catch basins. I have recommended that a couple of temporary leak-offs be installed along the curb line of the reach of Dart
Hill Rd east of the Debbie Dr. intersection leading to a temporary sediment basin to remove runoff from the slope during heavy rain storms.
The removal of the leak-offs and the addition of the plunge pool will minimize sediment impacts to the downstream wetland resources in the long term.