AQUIFER TESTING AND ANALYSIS ALONG RIVERS WITH CHANGING RIVER STAGE

Aquifer testing and analysis is difficult in situations where the groundwater system consists of multiple aquifers, the test area is located next to a large river with varying water levels, and large rainstorms occur during the test period. The natural variations in hydraulic conditions (i.e., varying river levels and rainstorm events) were valuable in conceptualizing and interpreting the groundwater flow system. Based on a large transient hydraulic events, groundwater levels in the upper silty, fine sand do not respond significantly to large precipitation events or high water levels in the upper reach of the Ohio River. It does respond slowly to changes to Ohio River water level below thge dam. The lower confined sand and gravel does not respond to large precipitation events, but does respond very rapidly and significantly with changes in river stage below the dam. Pumping tests showed a range of hydraulic conductivites of 152 to 342 ft/day for the shallow silty sand, 255 to 776 ft/day for the deeper sand and gravel layer, and 10.4 ft/day for the limestone bedrock.