Wells in the Ohio River alluvium yield several hundred gallons per minute; compound horizontal wells yield as much as 5,000 gallons per minute. In the limestones of the western three-quarters of the county, most drilled wells in uplands are adequate or enough for a domestic supply. Yields as high as 50 gallons per minute have been reported from wells penetrating large solution channels or fault zones. In the low-lying areas of Claylick and Livingston Creeks, and the tributaries to the Ohio River, most wells are inadequate for domestic use; if the well intercepts a major solution opening in the limestone, however, the yield may be very large. Groundwater is not as prevalent in the sandstone- and shale-rich eastern quarter of the county; most wells are inadequate for a domestic supply. Some wells in sandstone formations yield enough water for a domestic supply when located in areas bordering streams, however. Spring flows from a few gallons per minute to 1,400 gallons per minute occur in the county. Minimum flows are generally in early fall, maximum flows in late winter.