Mabee, S.B. 1999. Factors influencing well productivity in glaciated metamorphic rocks. (Accepted for publication in Ground Water in January-February 1999)

Eight factors were examined to determine their influence on the transmissivities of 35 domestic wells drilled in glaciated, metamorphic bedrock. Wells were grouped into various categories on the basis of bedrock type, topographic position, structural setting, proximity to fracture-correlated lineaments, overburden type, overburden thickness, proximity to surface water bodies, and water table depth. Results indicate that bedrock type, topographic setting proximity to fracture-correlated lineaments, and structural position explain 34%, 31%, 15% and 12% of the observed variation in transmissivity, respectively, and are the only variables that have a statistically significant (90% confidence level) relationship with transmissivity. For this study area, wells situated in amphibolite bedrock in upland valleys and flats located £25 m from fracture-correlated lineaments, and positioned on the axes of major folds are the most productive. Comparison of results from this study with those from three other investigations, each representing different geologic environments (carbonate, clastic sedimentary, and unglaciated metamorphic/igneous terrains), indicates that well productivity varies with geologic setting; a set of factors in one geologic environment does not necessarily have the same significance when applied to wells in a different geologic setting.

Back to Publications