Aquifer Tests and Well Field Performance, Scioto River Valley, Ohio: Part Ia

Abstract

ABSTRACTBased on 13 aquifer infiltration tests at 11 sites, aquifer transmissivity ranged from 17,000 to 40,000 square feet per day, and the streambed infiltration rate ranged from 0·06 to 0·19 million gallons per day per acre along a seven‐mile reach of the Scioto River in south‐central Ohio. Despite these wide ranges, the sand and gravel aquifer, 40 to 65 feet thick, underlying 10–20 feet of river alluvium south of the glacial boundary, is fairly homogeneous due largely to the absence of till interbeds.Performance of a major well field designed on the basis of the tests has been about as predicted, validating the techniques of data collection and analysis.At each site, a well for pumping was drilled on the floodplain, 150 to 750 feet from the river, and an array of observation wells was installed on lines extending through the pumped well, one line perpendicular to the river and the other parallel.Values of drawdown measured in the observation wells at the end of constant‐rate pumping periods, usually of three days duration, were used to determine line‐source distance and aquifer transmissivity. The rate of streambed infiltration and the streambed‐leakage factor, the latter term relating the infiltration rate to drawdown beneath the stream, also were determined at all but one site. Drive‐point wells installed in the riverbed, or along the near bank, in the vicinity of the pumped well were used to determine drawdown beneath the river due to pumping.