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At least 127 records · Page 7Linked to original sources
USGS1978

Water-level declines in the Madison area, Dane County, Wisconsin

The water supply for the city of Madison, Wisconsin, and for surrounding municipalities is obtained from the ground-water reservoir that underlies the area. This ground-water reservoir is composed of an upper aquifer and an underlying sandstone aquifer. High-capacity water-supply wells pump from the sandstone aquifer. Pumping from the sandstone aquifer has resulted in hydrologic changes. The water level has dropped in both the upper aquifer and underlying sandstone aquifer, and the flow of water in streams has been reduced. The effects of anticipated pumping were examined with the use of a digital model. The maximum water-level decline from the beginning of pumping in 1882 until 1975 was about 75 feet in the sandstone aquifer and 10 to 20 feet in the upper aquifer. Additional declines between 1975 and 2000 were computed to be 10 to 30 feet in the sandstone aquifer and 5 to 10 feet in the upper aquifer. The average annual streamflow of the Yahara River at the McFarland gaging station was reduced 32 percent from the beginning of pumping to 1975. An additional 7 percent reduction in streamflow was computed for the period 1975 to 2000.

Wisconsin↗
USGS1995

Simulation of stage and the the hydrologic budget of Devils Lake, Sauk County, Wisconsin

Water clarity of Devils Lake, in the Driftless Area of southwestern Wisconsin, has been decreasing because of blue-green algal blooms. An understanding of the hydrology of Devils Lake is needed to develop a mitigation plan to reduce phosphorus input. A model was developed to test the current understanding of the hydrology of the lake including stage and hydrologic budget and to estimate the effects of proposed mitigation plans on lake stage. Daily lake stage was simulated in the model by summing estimates of hydrologic-budget components. The Devils Lake hydrologic-budget components are precipitation on the lake surface, evaporation from the lake surface, runoff (consisting of overland flow to the lake and an intermittent stream flowing into the lake), and ground-water flow into and out of the lake. The model was calibrated to measured lake stage for the period 1980-92. Simulated stage compares reasonably well with historical stage data for Devils Lake. The root mean square of the differences of simulated and measured daily lake stages for the period 1980-92 is 0.83 foot. Simulated lake stage is very sensitive to small changes in runoff and evaporation coefficients, and ground-waterflow rates used in the model. The average model-calculated annual amounts of each hydrologic-budget component for the 1980-92 simulation period, in order of increasing volume, are evaporation (791 acre-feet), precipitation (973 acre-feet), runoff (1,107 acre-feet), and net ground-water flow, which is out of the lake (1,323 acre-feet). Three mitigation plans were simulated. Mitigation plan 3, which includes the addition of water from a basin adjacent to the northeastern side of the Devils Lake Basin, allows for withdrawals of hypolimnetic water and maintaining lake stage closer to optimal levels than would result without mitigation.

Wisconsin↗