Storm Water Management:

1. Storm Water Management: Using GIS to Direct Non-Point Source Pollution Mitigation Efforts in the Eagleville Brook Watershed Jason Parent (jason.parent@uconn.edu)

2. Background • In 2004, the Eagleville Brook watershed failed to meet Connecticut’s water quality standards • The federal Clean Water Act requires states to perform a Total Maximum Daily Load (TMDL) analysis for waters not meeting quality standards - when technology based controls are not adequate. • A TMDL analysis determines the maximum allowable pollutant load that lakes or rivers can receive while still meeting water quality standards.

3. Objectives • Perform TMDL analysis using impervious cover (i.e. paved or concrete surfaces) instead of specific pollutants. • Percent impervious cover found to be a good indicator of water quality in a watershed. • First TMDL study in nation that uses impervious cover. • Develop detailed site-specific recommendations for the University of Connecticut and the Town of Mansfield to use in development of their water quality management plans for the Eagleville Brook watershed.

4. Located in Mansfield, CT Covers 1200 acres 18% is covered by impervious surfaces The University of Connecticut’s Storrs campus covers a major portion of the watershed. The Eagleville Brook Watershed

5. Participants in the TMDL • University of Connecticut • Town of Mansfield • CT Department of Environmental Protection • The Center for Land Use Education and Research’s Nonpoint Education for Municipal Officials (NEMO) program • The Center for Watershed Protection • The Horsley-Witten Group

6. Plans for mitigation • Reduce storm water run-off from roads, parking lots, and rooftops that enters Eagleville Brook. • Disconnect impervious surfaces from the watershed with… • Retention basins • Drainage swales • Pervious parking lots

7. Developing a GIS database • Aerial imagery • Impervious surfaces • roads, parking lots, rooftops, sidewalks, etc. • Non-impervious land covers • Forest, turf, agricultural fields, etc. • Digital Elevation Model • Storm water drainage network • Parcels and zoning

8. Aerial imagery • UConn campus aerial image • spring of 2008 (leaf-off) • 0.5 ft resolution • True color image • National Agriculture Inventory Program (NAIP) imagery for Connecticut • summer 2008 • 1 meter resolution • true color and color infrared

9. campus aerial NAIP imagery Imagery

10. Impervious Cover • Any man-made surfaces that prevent water from infiltrating the ground • Rooftops, pavement, concrete, etc. • Digitized from high resolution (1 foot) aerial photographs for the watershed area. • Imagery taken in spring of 2008 • 6 classes identified: • Buildings, roads, parking lots, driveways, sidewalks, other impervious surfaces

11. Impervious cover map

12. Non-impervious land cover • Forests allow for infiltration of rain water into the ground reducing water runoff. • Turf and ag. land allows some water infiltration but runoff of storm water and nutrients may be significant. • Wetlands and ponds capture storm water run-off. • Forest, turf, and ag. lands digitized from high resolution (1 foot) aerial photographs (spring 2008) for the watershed area. • Wetland and ponds taken from CT DEP GIS data.

13. Non-impervious cover map

14. Digital Elevation Model (DEM) • For the campus area, DEM derived from 2ft contours (2004). • For remainder of watershed, DEM was based on CT Lidar data (20’ postings) – downloaded from clear.uconn.edu • Campus DEM imbedded in Mansfield DEM.

15. DEM 2’ contours TIN Lidar DEM Merge DEM’s Creating the DEM

16. Storm water drainage network • Need to identify impervious areas that can be disconnected from the storm water drainage network. • GIS maps of storm water drainage network provided by the town of Mansfield. • GIS maps of drainage network provided by UConn’s Architectural Engineering Services. • Map updated using 2008 aerial imagery

17. Storm water drainage network

18. Parcels and zoning • Parcel and zoning provided by the Town of Mansfield

19. Data Access through the Internetusing ArcGIS Server 9.3

20. 50 remedial projects proposed 10 selected for detailed review and feasibility assessment Proposed Remediation

21. Bioretention areas Drainage swales

22. Tennis courts with alternative pervious material Divert rooftop runoff to bio- retention area Bioretention area Rain garden

23. 4.2 acres Impervious area Bioretention area

24. Questions? Storm Water Management: Using GIS to Direct Non-Point Source Pollution Mitigation Efforts in the Eagleville Brook Watershed Jason Parent (jason.parent@uconn.edu)