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Homework Assignment

Using Online GIS to Protect Drinking Water Quality

due in two weeks


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.

In this assignment you will 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.

Final map and essay:

The final product of this assignment should be an essay and detailed maps that pinpoint two likely places to begin field research of potentially contaminated drinking water sources. You should include detailed information about both the source of pollution and about the well and water system it serves. Your final essay should include analysis methodology, research questions, critiques of the data categories or levels of resolution, and a summary of what you learned. Please spell out exactly how you arrived at your conclusions.

To submit the essay on disc: the final illustrated essay must be saved as an html document and submitted as 2 copies on 2 discs. **To copy map images, try the alt & print screen buttons to copy the browser window, then past it into Word or a graphics program.

To submit the essay on paper: If you do not know enough about computers to illustrate the essay, simply print out the maps, cut and manually paste your assignment together.


Hand in the final map and essay along with all of the maps and other data used in your research. Don't forget to include full citations and a bibliography to tell me where you got your maps and other information. For more information, please read how to hand in assignments.

Related links:

Will NAFTA Force US to Drink MTBE?

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