As part of a continuing program to define the thickness and extent of water-bearing sand and gravel deposits in southwestern Ohio, the U.S. Geological Survey, in cooperation with the Ohio Division of Water and The Miami Conservancy District, completed a seismic refraction survey of the Great Miami River valley and adjacent areas between Dayton and Hamilton, Ohio, in the fall of 1963. A similar survey of the adjoining lower Great Miami River and Whitewater River valleys was completed in 1962 (Watkins, 1963; Spieker and Watkins, unpublished data).
The area of the survey includes known or inferred portions of an interglacial drainage system which is deeply entrenched into bedrock. Ohio was covered by glaciers at least three times during the Pleistocene epoch. As each glacier melted, rock fragments absorbed by the glacier were transported and deposited in these buried valleys by torrents of meltwater. The total thickness of glacial drift is over 300 feet in some places.
Much of the glacial material is highly permeable and saturated with large quantities of water of good quality. The underlying bedrock is virtually impermeable and yields only meager quantities of water. The cities of Dayton, Middletown, Hamilton, and many industries in the Miami River valley rely on wells in the glacial deposits as their principal source of water. The purpose of the present survey is to define the thickness and extent of these important water-bearing formations. Such information will make possible a more accurate evaluation of the area's water resources than has previously have been possible.
