Application of ground penetrating radar to sub-alpine hydrogeology, Snowy Range, Wyoming.

摘要

A ground penetrating radar (GPR) survey was conducted at the Glacier Lakes Ecosystem Experiment Site, in the Snowy Range of Wyoming with the objective of determining the potential groundwater storage in the sediment overburden and determining the bedrock fracture density. The survey was completed along 12 transects with 100 MHz antennas using a Sensors and SoftwareRTM PulseEKKORTM 100 system. The step size between shots was 0.25 meters and the separation between the antennas was 1meter. Two common midpoint (CMP) surveys were conducted and the subsurface GPR velocity was determined to be 0.06 m/ns.;The survey results indicate that sediment overburden thickness ranges from 0 m at bedrock outcrops to > 9 m near East Glacier Lake. The volume of sediment at the study site estimated at 83,800 +/- 8,380 m3. Based on a grainsize analysis of representative soil pedons the average specific yield at the study site is estimated to be approximately 10%. Given these values for soil volume and specific yield, the potential groundwater storage is 8,380 +/- 838 m3 for the study site, which extrapolates to 61,300 +/- 6,130 m3 in groundwater storage in the East Glacier Lake watershed. The two dimensional bedrock fracture density was determined to be 1 fracture per 4,810 m2. The bedrock groundwater storage is undetermined.