Hydraulic relationships between buried valley sediments of the glacial drift and adjacent bedrock formations in northeastern Ohio, USA

Abstract

Buried valleys are ancient river or stream valleys that predate the recent glaciation and since have been filled with glacial till and/or outwash. Outwash deposits are known to store and transmit large amounts of groundwater. In addition to their intrinsic hydraulic properties, their productivity depends on their hydraulic relationships with the adjacent bedrock formations. These relationships are examined using a steady-state three-dimensional groundwater flow model through a section of a buried valley in northeastern Ohio, USA. The flow domain was divided into five hydrostratigraphic units: low-conductivity (K) till, high-K outwash, and three bedrock units (Pottsville Formation, Cuyahoga Group and Berea Sandstone). The model input was prepared using the data from well logs and drilling reports of residential water wells. The model was calibrated using observed heads with mean residual head error of 0.3 m. The calibrated model was used to quantify flux between the buried valley and bedrock formations. Mass balance was calculated to within an error of 2–3 %. Mass balance of the buried valley layer indicates that it receives 1.6 Mm3/year (≈40 % of the total inflow) from the adjacent bedrock aquifers: Pottsville Formation contributes 0.96 Mm3/year (60 %) while the Berea Sandstone 0.64 Mm3/year (40 %).