A STATUS REPORT ON THE U.S. GEOLOGICAL SURVEY’S DENVER BASIN GROUND-WATER RESOURCE EVALUATION

In 2004, the U.S. Geological Survey’s Ground-Water Resources Program initiated three regional ground-water resource evaluations across the United States: Atlantic Coastal Plain of North and South Carolina, California Central Valley, and Denver Basin. The four-year projects will update computer models of ground-water conditions in some of the Nation’s most important and heavily used aquifer systems to assess changes in ground-water levels and ground-water-surface-water interaction since initial evaluations in the 1980s and to develop recommendations regarding long-term ground-water-level monitoring networks.

The Denver Basin aquifers are important sources of water for municipal, industrial, and domestic uses in the Denver and Colorado Springs metropolitan areas especially in Douglas and El Paso Counties where rapid urban growth continues and surface-water supplies are lacking. Objectives of the Denver Basin ground-water resources evaluation are (1) enhance understanding of regional ground-water flow and aquifer storage in the Denver Basin and overlying surficial aquifers; (2) evaluate changes in water levels, aquifer storage, and ground-water-surface-water interactions resulting from withdrawal; and (3) assess existing water-level monitoring and develop recommendations for future monitoring activities. The USGS is working in partnership with the Colorado Water Conservation Board, the Colorado State Engineer’s Office, and local water-management agencies to implement the Denver Basin ground-water resources project. Project objectives will be met by developing and calibrating a transient, fully-three-dimensional ground-water flow model of the Denver Basin aquifer system. Data compilation, initial ground-water flow modeling, and water-level monitoring assessment will be accomplished in 2004 and 2005. Evaluation of pumping effects will occur in 2006, and planned publication products will be completed in 2007.