Water Resources of Clarke County, Virginia

The Northern Shenandoah Valley is underlain by karst and fractured-rock aquifers that are increasingly being relied upon to supply water to local communities and individual residences. This is an area with an expanding economy and a growing population, and, to meet future water needs, these aquifers are likely to be developed to supplement current withdrawals. The recent prolonged drought (1998-2002) has focused attention in Clarke County, Virginia on the quantity and sustainability of the ground-water resources. An improved understanding of these complex aquifer systems is required to effectively develop and manage them as sustainable water supplies. In order to assess current and future hydrologic conditions within the County, a long-term monitoring network was designed and implemented. Furthermore, hydrogeologic information provided by a detailed aquifer appraisal provides useful information to better address questions about (1) the quantity of water available for use, (2) the effects of increased pumpage on ground-water levels and instream flows, and (3) the quality of the ground-water supply and its vulnerability to current and potential future sources of contamination.

Hydrogeologic Setting and Project Background

Karst and fractured-rock aquifers

The area considered in this study encompasses both the carbonate and non-carbonate rocks in Clarke County, Va. Water-quality protection efforts—as outlined in the Water Resources, Groundwater Resources, and the Surface Water Resources Plans—are included in the County's Comprehensive Plan. These efforts are based on previous investigations that have been conducted in the County since the late-1980s. The establishment of a long-term data network and further evaluation of information from previous studies was part of this hydrogeologic assessment, and will aid future land-use and water-supply planning activities in the County.

For information, contact David Nelms at dlnelms@usgs.gov

Clarke County Water-Monitoring Networks

The Virginia Water Science Center, in cooperation with Clarke County, maintains a network of water-monitoring stations measuring many aspects of surface and ground water, along with water-quality parameters.

     Real-time networks

     Quarterly networks