USE OF IMPROVED HYDROLOGIC TESTING AND BOREHOLE GEOPHYSICAL LOGGING METHODS FOR AQUIFER CHARACTERIZATION

Depth-discrete aquifer information was obtained using recently develop ed adaptations and improvements to conventional characterization techn iques. These improvements included running neutron porosity and bulk d ensity geophysical logging tools through a cased hole, performing an e nhanced point-dilution tracer test for monitoring tracer concentration as a function of time and depth, and using pressure derivatives for d iagnostic and quantitative analysis of constant rate discharge test da ta. Data results from the use of these techniques were used to develop a conceptual model of a heterogeneous aquifer. Depth-discrete adquife r information was required to effectively design field-scale deploymen t and monitoring of an in situ bioremediation technology. Geophysical logging and point-dilution tracer test results provided the relative d istribution of porosity and horizontal hydraulic conductivity, respect ively, with depth and correlated well. Hydraulic pumping tests were co nducted to estimate mean values for transmissivity and effective hydra ulic conductivity. Tracer test and geophysical logging results indicat ed that ground water flow was predominant in the upper approximate 10 feet of the aquifer investigated. These results were used to delineate a more representative interval thickness for estimating effective hyd raulic conductivity. Hydraulic conductivity, calculated using this rep resentative interval, was estimated to be 73 ft/d, approximately three times higher than that calculated using the full length of the screen ed test interval.