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Using Online GIS to Protect Drinking Water Quality


You are conducting research in Santa Clara County to assess the potential impact of pollution on drinking water quality. Because of a very limited budget, you are only able to research the spread of pollution around a few water systems and wells. That is why you must look at environmental data to pinpoint the most likely places to begin field research of drinking water sources vulnerable to contamination.

You can use the online GIS Geotracker to collect and analyze maps of environmental data for Santa Clara County. GeoTracker is the interface to the Geographic Environmental Information Management System (GEIMS), a data warehouse which tracks regulatory data about underground fuel tanks, fuel pipelines, and public drinking water supplies.

Gathering data and pinpointing a site:

Determine the distance between contaminant sites and sensitive drinking water sources. Assume the closer a well is to a contaminant site, the more vulnerable it is to contamination.

The tools built into GeoTracker can quickly identify and display the number of leaking underground fuel tank (LUFT) sites within various distances of wells. You can get the program to display wells that are within an estimated "Zone of Influence for a Contaminant Site" (specified around the site as a fixed radius of distance 1000-2640 ft.). Remember, you will have to zoom in to see the details.

A set of on-line tools allows the user to integrate well specific and contaminant site specific information to give users the potential to analyze various aspects of vulnerability.

Try to pinpoint a likely place to begin field research of potentially contaminated drinking water sources. You should be able to access detailed information about both the source of pollution and about the well and water system it serves.

Related links:

Silicon Valley Toxics Coalition
- groundwater contamination and county demographic maps
- new Eco-Maps of SiliconValley

Maps and Technology: GIS/GPS - Resources

The Hydrologic Cycle and Ground Water Resources

(MTBE) Impacts to California Groundwater