Extreme BMP Makeover Eagleville Brook Impervious Cover TMDL

Storrs, CT (October 26, 2009)- Eagleville Brook is an impaired stream that flows through a highly urbanized area of the University of Connecticut (UConn) Campus and down into the rural Town of Mansfield, CT where it meets the Willimantic River. The brook is piped under the most developed section of campus and daylights off-campus further downstream near the Town of Mansfield.



The Brook watershed was recently issued an impervious cover (IC) Total Maximum Daily Load (TMDL) by Connecticut Department of Environmental Protection (CTDEP). Representing the first of its kind in the nation, the TMDL is not based on a specific pollutant, but rather on an indicator of the impacts of urban development. CTDEP set a target watershed impervious cover of 11% for streams, with a 50 square mile drainage area or smaller. The 2.4 square mile Brook watershed, which is 18.9% impervious, exceeds the target by 97 acres, primarily in the highly urbanized section of the UConn campus.
The objective of this project is to meet the TMDL requirements by reducing the amount of effective IC in the watershed by either removing IC or by disconnecting it through LID practices to treat runoff.
In response to this objective, the Center, along with Horsley Witten Group, UConn, CTDEP, and the Town of Mansfield identified approximately 50 stormwater retrofit opportunities for disconnection on the UConn campus. Retrofit projects identified included: bioretention, rainwater harvesting, permeable pavement, green roofs, rooftop disconnection to cisterns or turf, wetland creation/restoration, and soil amendments in compacted lawn areas.
The UConn campus offers a unique opportunity to achieve project implementation because of the campus’s commitment to the environment and green building, and the rate at which redevelopment projects are being implemented. Two parking lots have already been replaced with permeable pavement, and a green roof has been installed.
The next steps of the project are to identify the highest priority and near-term projects, and then to document a method that other communities can use to address future IC-based TMDLs. This project has broad implications for communities nationwide seeking to use IC as a guide to progress in restoring or protecting their watersheds.
Related Resources:
Eagle Brook Watershed TMDL Project