This report describes ground-water tracing investigation done by Cambrian Groundwater in the Nelson -Wooster - Humphrey Tunnel system during September 2001. A fluorescent dye tracer was injected and recovered at various locations inside and outside the mine system and the results used to infer flow conditions in the tunnel. Tritium data that had been collected were also interpreted. Using these two tracers enables water tracing to be done in mixtures of ground waters that have residence times of hours to decades. Quantitative tracing of ground water enables an estimate to be made of hydraulic and other parameters along pathways where parts of subterranean pathways are not accessible for physical examination.

Results of Groundwater Tracing Experiments in the Nelson-Wooster-Humphrey Tunnel