The U.S. Geological Survey Data Series provides raster data representing an estimate of aquifer vulnerability calculated for each 30-meter raster cell. Depth to water, Recharge, Aquifer media, Soil media, Topography, Impact of the vadose zone, and hydraulic Conductivity of the aquifer (DRASTIC) are represented geospatially and used to calculate aquifer vulnerability. The DRASTIC approach to calculating aquifer vulnerability involves developing an index, based on geospatial information, which rates how susceptible the aquifers underlying different areas are to receive chemicals introduced at land surface. The physical data represented in each geospatial layer was assigned an index value and a weight multiplier used to indicate the importance of each type of data. The weighted sum of the layers was then calculated to achieve the aquifer vulnerability score