Water Quality in the Edwards Aquifer Katrina E. Mabin CE 394K GIS in Water Resources Dr. D. R. Maidment Counties of study Williamson Travis Hays Data from TWDB Edwards Aquifer Data from TWDB Add well data Well data covers entire state Need to select locations important to study Qualifications for use Select only wells with water quality data: Select objects by attributes (WATER_QUAL), then save selection as layer and export as a shapefile Select only wells within study counties and Edwards aquifer: Select objects by location (those falling within the features of another layer) Obtained groundwater data for Travis County from Texas Water Development Board (TWDB) website referenced by state well ID Convert.xls file to.dbf file to be included in geodatabase as object class Joined object class (travis_wq) to feature class (edwards_wells) Selected wells with water quality data from 1999 only 12 wells within Travis Co. Interpolate points to raster: can Spatial Analyst depict chemical gradients in groundwater? Calculate spline of TDS values associated with Travis Co wells in Edwards Aquifer (1999 data) Very few points, so Spatial Analyst interpolates breach of Higher TDS water across aquifer Drinking water standards