Managing Louisiana's Public Water Supply With GIS

The Safe Drinking Water Act Amendments (SDWA) of 1996 requires that all states develop a Source Water Assessment Program (SWAP) to ensure safe water for all citizens through the protection of water resources. In Louisiana, more than 3,200 public water wells and 50 surface water intakes supply Louisiana's four and one-half million citizens and an estimated 20 million annual visitors.

For the Louisiana SWAP, the only way to fully harness all the components of a vast and diverse public water network in the state was to develop a full-scale GIS. This map is a compilation of some of the components that represent the many different avenues through which public water is distributed and identifies potential risks that could affect quality and/or availability.

From 1,000-foot-deep wells to intakes along lakes and the Mississippi River, spatial and attribute information was collected and various calculations applied. Geospatial technologies were used to assemble data from more than 20,000 field-collected GPS points, 25 statewide data sets, and information obtained from local water system operators into an extensive geodatabase. This information was compiled to assess Louisiana's potable water source sensitivity, vulnerability, and susceptibility. Both hard-copy and online reports and maps were generated to notify appropriate state and local individuals of their water source status so they could take action if necessary.