1. 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

2. Fluorescent Dyes:
Cheap to purchase ($20 - $50 per pound)
Low cost analysis ($15 - $25 per analysis)
Low detectability ( ppt)
Non-toxic compounds

3. Fluorescent Dyes:
Determine Groundwater Flowpaths
Evaluate geologic controls
Time of Travel
Relative Vulnerability of Groundwater Resources
Aquifer assimilative capacity

4. Can be field labor intensive
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
COMAL SPRINGS SHOWING MONITORING POINTS, WELLS, AND INJECTION POINTS
LCRA WELL
PANTHER CANYON WELL

5. Breakthrough Curves at Landa Lake Outlet
Comal Springs Discharge
( cfs)
Eosine From Panther Canyon Well
Uranine from LCRA Well
DYE BREAKTHROUGH CURVES FOR EOSINE AND URANINE
NOTE DYE BREAKDOWN FROM LIGHT EXPOSURE DURING DAY AS DYE CROSSES LANDA LAKE
Uranine results indicate photodegradation of dye as it crosses Landa Lake

6. Geologic Map Dolomitic Travel time - 3 miles per day Basal Nodular
Cyclic & Marine

7. 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,