DYE TRACING FUNDAMENTALS
Ralph O. Ewers, Ph.D.Peter J. Idstein, [email protected]
DYE TRACING FUNDAMENTALS
• Where are the groundwater basin boundaries ?• Where does the water go ?• How long does it take to get there ?• What happens along the way ?
Questions Answered By Tracing
DYE TRACING FUNDAMENTALS
• Monitoring Locations and Reconnaissance• Background Determination• Dye Injection• Dye Monitoring• Dye Analyses
Dye Properties
• Non-Toxic• Soluble in water – thus easy to introduce• Unmistakably detectable at extremely low
concentrations• Durable in the aquifer environment• Easily quantified• A proven record of use in karst aquifers• Inexpensive to obtain and analyze
Monitoring Locations
• Springs• Streams• Cave Streams and Karst Windows • Production/Domestic Wells• Monitoring Wells
Reconnaissance Essentials
• Search for springs along streams surrounding the site.
• Search for springs in stream valleys across the adjacent divide from the site.
• Select stream monitoring sites to insure that hidden springs will be monitored.
• Look for streams in caves.• Assess nearby wells of all types.• Look for dye introduction points that bracket the
site.
Dye Background Determination
• One week exposure for dye receptors (typical)• Two sampling rounds (exchanges) are usual
Dye Background Determination
• One week exposure for dye receptors (typical)• Two sampling rounds (exchanges) are usual• Analyze for all potentially useful fluorescent
dyes
Dye Background Determination
• One week exposure for dye receptors (typical)• Two sampling rounds (exchanges) are usual• Analyze for all potentially useful fluorescent
dyes
• Choose the dye to be used for tracing based upon dye background and dye properties
Dye Monitoring
• Always exchange dye receptors NEVER remove them
• Typical intervals are weekly or bi-weekly
Dye Monitoring
• Always exchange dye receptors NEVER remove them
• Typical intervals are weekly or bi-weekly• Disposable gloves are typically worn
Dye Monitoring
• Always exchange dye receptors NEVER remove them
• Typical intervals are weekly or bi-weekly• Disposable gloves are typically worn • Transport of dye receptors is by express at
ambient temperature
Dye Monitoring
• Always exchange dye receptors NEVER remove them
• Typical intervals are weekly or bi-weekly• Disposable gloves are typically worn • Transport of dye receptors is by express at
ambient temperature • Water samples are often used to provide
additional custody assurance
Dye Analyses
• Synchronous spectrofluorophotometry is the standard analytical technique
• Modern instruments provide part-per-trillion sensitivity for fluorescent dyes
Dye Analyses
• Synchronous spectrofluorophotometry is the standard analytical technique
• Modern instruments provide part-per-trillion sensitivity for fluorescent dyes
• Activated carbon dye receptors provide 400 to 1000 fold increase in dye concentration relative to the concentration in the ambient water