The use of fluorescent tracers as a groundwater investigation tool Presented by: Geary M. Schindel, P. G. Chief Technical Officer Edwards Aquifer Authority San Antonio, Texas
Fluorescent Dyes: • Cheap to purchase ($20 - $50 per pound) • Low cost analysis ($15 - $25 per analysis) • Low detectability (10 - 20 ppt) • Non-toxic compounds
Fluorescent Dyes: • Determine Groundwater Flowpaths • Evaluate geologic controls • Time of Travel • Relative Vulnerability of Groundwater Resources • Aquifer assimilative capacity
Fluorescent Dyes: • Can be field labor intensive • Requires identification of recharge and discharge points • Collection and analysis of samples • Requires knowledge and experience with tracer test design
Breakthrough Curves at Landa Lake Outlet Eosine From Panther Canyon Well Comal Springs Discharge (366 - 352 cfs) Uranine from LCRA Well Uranine results indicate photodegradation of dye as it crosses Landa Lake
Geologic Map vel Tra Dolomitic time y r da s pe mile - 3 Basal Nodular Cyclic & Marine
One well-designed tracer test, properly done, and correctly interpreted, is worth a 1000 expert opinions. . . or 100 computer simulations of groundwater flow Dr. James F. Quinlan Tracer tests will change your conceptual understanding of groundwater flow – towards reality Dr. E. Calvin Alexander,