1 Storm Water Management: Using GIS to Direct Non-Point Source Pollution Mitigation Efforts in the Eagleville Brook Watershed Jason Parent

2 Background In 2004, the Eagleville Brook watershed failed to meet Connecticut’s water quality standards 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. 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. 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. 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. Percent impervious cover found to be a good indicator of water quality in a watershed. First TMDL study in nation that uses impervious cover. 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. 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 The Eagleville Brook Watershed Located in Mansfield, CT Located in Mansfield, CT Covers 1200 acres Covers 1200 acres 18% is covered by impervious surfaces 18% is covered by impervious surfaces The University of Connecticut’s Storrs campus covers a major portion of the watershed. The University of Connecticut’s Storrs campus covers a major portion of the watershed.

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

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

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

8 Aerial imagery UConn campus aerial image UConn campus aerial image spring of 2008 (leaf-off) spring of 2008 (leaf-off) 0.5 ft resolution 0.5 ft resolution True color image True color image National Agriculture Inventory Program (NAIP) imagery for Connecticut National Agriculture Inventory Program (NAIP) imagery for Connecticut summer 2008 summer meter resolution 1 meter resolution true color and color infrared 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 Any man-made surfaces that prevent water from infiltrating the ground Rooftops, pavement, concrete, etc. Rooftops, pavement, concrete, etc. Digitized from high resolution (1 foot) aerial photographs for the watershed area. Digitized from high resolution (1 foot) aerial photographs for the watershed area. Imagery taken in spring of 2008 Imagery taken in spring of classes identified: 6 classes identified: Buildings, roads, parking lots, driveways, sidewalks, other impervious surfaces 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. 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. 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. 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. 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. 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 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 For remainder of watershed, DEM was based on CT Lidar data (20’ postings) – downloaded from clear.uconn.edu Campus DEM imbedded in Mansfield DEM. Campus DEM imbedded in Mansfield DEM.

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

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

17 Storm water drainage network

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

19 Data Access through the Internet using ArcGIS Server 9.3

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

21 Bioretention areas Drainage swales

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

23 Bioretention area 4.2 acres Impervious area

24 Storm Water Management: Using GIS to Direct Non-Point Source Pollution Mitigation Efforts in the Eagleville Brook Watershed Jason Parent Questions?