The use of temperature as a ground-water tracer in glacial outwash

Abstract

A twenty-four hour, divergent-flow thermal tracer experiment was conducted to determine the usefulness of heat as a ground-water tracer. Bromide was used also in the experiment, as a means of comparing the thermal tracer to a conservative chemical species. Observations of pore-fluid temperature and bromide concentration were made at seven points within 3.1 meters of a partially-penetrating injection well. Results show that temperature may be used effectively in the determination of aquifer heterogeneity and aquifer transport and thermal properties. Aquifer porosity was determined to be between 0.35 to 0.61. Longitudinal mass and thermal dispersivities were computed to have been between 0.012 to 0.124 meters, and apparent thermal conductivities were 3.4 to 25.9 times greater than the bulk thermal conductivity of the aquifer. The high conductivities point to the importance of thermal dispersion to the overall transport of a thermal plume during an injection experiment.