Storm Water Management:

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Storm Water Management

• Using GIS to Direct Non-Point Source Pollution
  Mitigation Efforts in the Eagleville Brook
  Watershed

Jason Parent (jason.parent_at_uconn.edu)
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Background

• In 2004, the Eagleville Brook watershed failed to
  meet Connecticuts 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.

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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.

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The Eagleville Brook Watershed

• Located in Mansfield, CT
• Covers 1200 acres
• 18 is covered by impervious surfaces
• The University of Connecticuts Storrs campus
  covers a major portion of the watershed.

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Participants in the TMDL

• University of Connecticut
• Town of Mansfield
• CT Department of Environmental Protection
• The Center for Land Use Education and Researchs
  Nonpoint Education for Municipal Officials (NEMO)
  program
• The Center for Watershed Protection
• The Horsley-Witten Group

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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

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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

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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

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Imagery
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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

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Impervious cover map
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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.

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Non-impervious cover map
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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.

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Creating the DEM
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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 UConns
  Architectural Engineering Services.
• Map updated using 2008 aerial imagery

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Storm water drainage network
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Parcels and zoning

• Parcel and zoning provided by the Town of
  Mansfield

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Data Access through the Internetusing ArcGIS
Server 9.3
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Proposed Remediation

• 50 remedial projects proposed
• 10 selected for detailed review and feasibility
  assessment

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4.2 acres Impervious area
Bioretention area
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Storm Water Management
Questions?

• Using GIS to Direct Non-Point Source Pollution
  Mitigation Efforts in the Eagleville Brook
  Watershed

Jason Parent (jason.parent_at_uconn.edu)