DYE TRACING FUNDAMENTALS

Ralph O. Ewers, Ph.D.Peter J. Idstein, M.S.ewc@mis.net

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

Fluorescent Dyes

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

Activated Carbon Dye Receptors

Monitoring Locations

• Springs• Streams• Cave Streams and Karst Windows • Production/Domestic Wells• Monitoring Wells

A Typical Monitoring Scheme

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.

A Typical Monitoring Scheme

24 Springs19 Stream Locations3 Domestic Wells6 Monitoring Wells

Dye Background Determination

• One week exposure for dye receptors (typical)

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 InjectionSinking Stream

Dye InjectionBackhoe Trench

Dye InjectionSinkhole

Dye InjectionWell

Dye Injection via Well

Don’t pour it in like this

Dye Injection via Well

Because when you add the necessary water……

Dye Injection via Well

You will get this !

Dye Injection via Well

Stagnant Dye Mass

Well Injection System

Dye Injection via Well

Tremi TubeThe Tremi Method

Dye Injection via Well

Tremi Tube

Upward Flush With Potable Water

Dye Injection via Well

Tremi Tube

Upward Flush With Potable Water

Downward Flush With Potable Water

Dye Monitoring

Dye Monitoring

Dye Monitoring

• Always exchange dye receptors NEVER remove them

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

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

Dye AnalysesLaboratory Protocol

Washing

Drying

Weighing

Elution

Elution

Analysis

Analysis

Analysis

There’s No Truth Like TTRRAACCEERR Truth

Quinlan, 85

End

Part 3