Assessing the vulnerability of public-supply wells to contamination--Edwards aquifer near San Antonio, Texas

http://pubs.usgs.gov/fs/2011/3142/

Well vulnerability results from the young age of groundwater. Karst features permit contaminants to move into the aquifer easily, leading to a well mixed aquifer; geochemical processes do not degrade contaminants quickly.

by Jagucki, Martha L.; Musgrove, MaryLynn; Lindgren, Richard J.; Fahlquist, Lynne S.; and Eberts, Sandra M.

U.S. Geological Survey Fact Sheet 2011-3142