Water Tracing Methodology - PUB2974

The department's Missouri Geological Survey water tracing methodologies have been developed over a period of more than four decades to improve the quality of data collected and the interpretation of that data. The standardized process is summarized below:

• Field work is begun to determine locations of suitable monitoring and injection points that have the potential to produce useful data.
• Activated carbon is placed in select springs and surface water monitoring points as backgrounds, to determine if fluorescent compounds are present in the water which could interfere with the tracers to be used in the study.
• Water samples may be used to either supplement or replace the carbon and cotton packets data as conditions warrant.
• These packets are normally collected and replaced on a weekly basis thereafter.
• The background packets (as well as subsequently collected packets) and water samples are analyzed at the department's Water Tracing Laboratory in Rolla, Missouri, using a synchronously scanning spectrofluorometer.
• The specific tracers and amounts to be used in a particular study are selected only after interpretation of background analysis.
• Tracers are injected at locations selected to yield useful data.
• As the subsequent packets and/or water samples are analyzed, the information obtained from each analysis is evaluated to determine if the injected tracers are present at each monitoring point.
• If the MGS Water tracing Committee concurs with the investigator, the dye trace is approved by the committee and the pertinent information is entered into the department's dyetrace database, which is a summary of the dyetrace results.
• Whether the trace is approved or not approved, the data are archived in the department's dyetrace files.

Please direct questions to gspeg@dnr.mo.gov