Ground-water levels and tritium concentrations at the Maxey Flats low-level radioactive waste disposal site near Morehead, Kentucky, June 1984 to April 1989

The Maxey Flats disposal site, Kentucky encompasses about 280 acres near the edge of a flat-topped ridge. The ridge is underlain by fractured shale and sandstone beds of the Nancy Member and the Farmers Member of the Borden Formation of Mississippian age. Groundwater flow in the strata beneath the site occurs through fractures, and flow patterns are difficult to delineate. The potentiometric surface also is difficult to delineate because several saturated and unsaturated zones are present in the rocks. Generally, ground-water levels in wells intersecting permeable fractures fluctuated seasonally and were lowest from December through June and highest from July through November. Water levels in the disposal trenches fluctuations less than those in wells, and for most trenches the fluctuations were less than 0.5 foot. From June 1984 to April 1989, tritium concentrations in groundwater ranged from 0 to 2,402,200 picocuries/ml. The greatest and most variable tritium concentrations were in wells along the northwest side of the site. The major conduit of groundwater flow from the trenches in the northwestern part of the site is a fractured sandstone bed that forms the base of most trenches. Elsewhere along the site perimeter, elevated levels of tritium were not detected in wells, and mean tritium were not detected in wells, and mean tritium concentrations showed little change between 1986 and 1988