This part of the website will document and track low impact development practices at UConn and Mansfield as they are implemented. The project-by-project list will take you to pages containing photos, videos, and other information. For locating these projects within the watershed, use the Implementation Mashup. (Note: some projects were completed before the IC-TMDL project).
The mashup is a map that shows the location of projects implemented as part of the IC TMDL response site using Google Maps. Click on a balloon to access links to related information for each site. Or, to see a list of sights view the Eagleville Brook Implementation Sites in a larger map.
Is the Impervious Cover TMDL a mandate to get out the jackhammers?
We don’t think so. And, perhaps more important is that CT DEEP doesn’t think so either, as evidenced by the guidance in the Eagleville TMDL final report (read excerpt) (read report). While biological integrity of the brook is the bottom-line goal, the team interprets the interim goals as related to two key watershed management concepts: impervious cover disconnection and runoff reduction (key references are in the Library).
Without the Impervious Cover TMDL target and a way to measure progress against it, this project would be a simple stormwater retrofit effort. Based on the approach outline above, the team recommends that progress be measured on three levels:
1. Amount of Impervious Cover Disconnected
What’s an IC-TMDL without an accounting of impervious cover?
The tables below summarize impervious cover data about the watershed, and about the effect that the project’s recommended stormwater practices are estimated to have on effective impervious cover. Table 1, included also in the Watershed Characterization page of this site, summarizes our estimates of existing impervious cover and the IC disconnection targets that result. Table 2, below, shows our estimates of the changes to impervious cover resulting from implementation, both of our “Top 10” retrofits only, and of retrofits at all 51 sites. On this strict acre-by-acre accounting level, the 11% TMDL goal appears to be achievable.
2. Runoff Volume Reduction
Stormwater researchers and managers are increasingly focusing on reduction of runoff volume as a key strategy in nonpoint source pollution control (key reference). This project hopes to look at volume several ways:
- Monitoring: a research weir on Eagleville Brook, located just south of the main part of campus, has been renovated and daily volume measurements are being made. See information on weir.
- Estimationusing standard formulas: Estimates of runoff volume reduction for a 1” storm were made for each of the 51 retrofits. Together, they total a reduction of about 2.5 million cubic feet of water annually.
- Modeling: The UConn Civil Engineering Dept. hopes to do some simple modeling of runoff in the watershed using the SWMM model to determine the volume impact of stormwater practices, both implemented and planned.
Runoff reduction estimates are included in Table 3, below. Also included are estimates of reduction of key pollutants, and cost estimates.
3. Biological Health of the Stream
CT DEEP will continue its fish and macroinvertebrate sampling program in Eagleville Brook to assess the “bottom line” of the success of the IC-TMDL effort.
Plans & Policies
A Watershed-Based Plan for Eagleville Brook has been developed, summarizing the findings of this study and making recommendations for ongoing implementation of the IC-TMDL (more about watershed-based plans here). With the Plan as the overall guide, the project team is working with the Mansfield Planning & Zoning Office and the UConn Offices of Environmental Policy and University Planning to assist them in codifying their commitment to Low Impact Development within the development design and approval process. Draft LID Checklists for both the University and the Town are currently under consideration.