Hydrogeology of the Leadville limestone and other paleozoic rocks in northwestern Colorado, with results of aquifer tests at Glenwood Springs

Paleozoic rocks in northwestern Colorado were investigated during the U.S. Geological Survey 's Regional Aquifer Systems Analysis of the Upper Colorado River Basin. Paleozoic rocks in the study area are grouped into 11 hydrostratigraphic units on the basis of lithologic and hydrologic properties. Devonian and Mississippian carbonate rocks and Pennsylvanian and Permian sandstone are regional aquifers, with natural discharges commonly ranging from 50 to 1,000 gal/min. Other hydrostratigraphic units in the area are either local aquifers or confining layers, with discharges rarely exceeding 50 gal/min. Aquifer tests at Glenwood Springs indicate that the Devonian and Mississippian carbonate rocks unit locally has a transmissivity of 47,000 sq ft/day, a storage coefficient of 0.0005, and a hydraulic conductivity of more than 100 ft/day. Hydraulic conductivities in most hydrostratigraphic units decrease with distance away from structural uplifts. Water in the Devonian and Mississippian carbonate rocks unit flows from structural uplifts to structural and fluvial basins. This hydrostratigraphic unit supplies water to streams that drain the White River Plateau, hot springs at Glenwood Springs, and artesian wells in the Burns basin. (USGS)