Geophysical data are recorded for water wells and test holes, but interpretation is subject to significant uncertainties. The data are used in ground-water models to evaluate potential waste disposal sites and the effects of ground-water contamination and to guide development of aquifers, including geothermal reservoirs. The development of quantitative log-interpretation techniques to derive more accurate data and to evaluate the statistical uncertainty in the data will reduce costs in ground-water investigations. Project objectives are to (1) evaluate presently available logging equipment and log-interpretation packages and develop improved instrumentation and analytical techniques for specific ground-water problems such as site selection and monitoring for disposal of radioactive, municipal, and industrial wasters, improve log derived estimates of physical properties, such as porosity values, (3) relate the log character of fractures to their hydraulic conductivities, (4) develop the capability of making quantitative interpretation of borehole gamma spectra, and (5) perform statistical analyses of the magnitude and sources of errors in log-derived data.
