ESTIMATING LOCAL GROUNDWATER-FLOW CONDITIONS IN A GRANITOID - PRELIMINARY ASSESSMENTS IN THE WALDOBORO PLUTON COMPLEX, MAINE

Periodic dry wells are reported by some homeowners in Knox and Lincoln Counties, Maine, These wells pump from the migmatitic Bucksport Fm. w hich is intermixed with the granitoids of the Waldoboro Pluton Complex , Previous remote sensing and geologic mapping delineated marked north east-trending structures in the WPC which were initially suspected as influencing ground-water flow for sustainable well yields, A sample ar ea, Pemaquid Pond, in the WPC was studied in more detail including pre liminary hydraulic testing of homeowner wells and ground-water flow mo deling. Wells with sustainable and greater yields appear to be associa ted instead with zones of northwest-trending structures in granitoids not intermixed with the Bucksport Fm. Dry wells appear to be more prev alent amongst northeast-trending structures in areas where the migmati tic metamorphic rocks outcrop, Hydraulic studies, including pumping, s lug, pressure, and borehole dilution testing, resulted in a wide range of calculated hydraulic conductivities, Dual-porosity flow modeling a nd geostatistical parameterization of the flow conditions suggest that the anisotropic hydraulic conductivity is near E-9 m/d.