Follow the Pollution
The 1987 amendments to the Clean Water Act 1.) identified urban storm water runoff as a source of water pollution,
and 2.) recognized the need to study the sources of runoff and other factors contributing to water pollution.
Indiana State Rule 13 is a similar measure which applies to entities with sewer system that discharge storm water.
The challenge was to meet State and Federal compliance requirements, and develop a long-term water quality analysis plan.
Using Geographic Information Systems (GIS), the Monroe County Planning Department developed a Stream Assessment
which gives an overview of water quality.
The first step was to determine the amount of runoff produced by different areas. Planners developed a unique process
which uses zoning classifications to calculate both current and future impervious surface estimates. Those areas with
more impervious surfaces, like parking lots and driveways, generate more runoff. Next came the lengthy process of
reviewing and classifying parcels according to land use. Finally, benchmarks were used in calculations to provide a
snapshot of long-term water quality impacts in a given area.
The completed assessment shows where runoff originates, indicates land use on each property, and determines which water
bodies are affected by the runoff. This combined data provides a baseline for future comparison, and is a
key component in analyzing the effects of land use on water quality over time.
Using their GIS, the Forestry Division is able to act quickly and decisively to counter the Ash Borer.
Forestry staff surveys wooded areas, examining trees and looking for D-shaped holes - the calling card of the Ash Borer.
If they find an infested tree, they relay the GPS coordinates back to the office, where GIS staff "lights it up."
The coordinates are plugged into the GIS - which includes digital aerial photography of the state - and a half-mile
buffer zone is drawn around each infested tree. Staff use the photography to mark every ash tree in the buffer zone,
then plan and organize removal and destruction.
Forestry also maintains parcel information. So not only can they find the ash trees that need to be cut and
burned, they can identify and contact any property owners that will be affected. GIS then becomes a tool for
explaining how important the eradication effort is. Maps showing nearby at-risk forests clearly illustrate
why it is necessary to kill the trees in the buffer zone.
Results
- Monroe County planners developed a highly-effective water quality analysis tool
- Planners can see which bodies of water are most heavily affected by pollution from storm water
- The impact of future development can be seen before it is approved
- Investigative and corrective resources can be prioritized based on quantifiable needs
- The evaluation process was designed to be easily replicated for use by all levels of government
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