(Published Monday, January 22, 2007 11:37:04 AM CST)
A d v e r t i s e m e n t
By Chris Schultz Gazette staff
WILLIAMS BAY-High-capacity wells are lowering the water table on the west side of Geneva Lake, according to a study for the Geneva Lake Environmental Agency.
The severity of the drawdown and its impacts will require a more in-depth study, said Ted Peters, environmental agency director. Impacts to the north and east are less severe.
The study was conducted by the Wisconsin Geological and Natural History Survey using a computer simulation.
The study shows wells create "cones of depression" within an aquifer. Greater water demand means more water is pumped, resulting in deeper and wider cones of depression, Peters said.
The study focused on 28 high-capacity wells-19 in the Fontana-Walworth area, five near Williams Bay and four in Lake Geneva.
The major recharge area for groundwater in the Geneva Lake area is the prairie west of the lake near Fontana and Walworth, Peters said.
And it's on that side of the lake-near Fontana, Walworth and Williams Bay-that the drawdown by high-capacity wells seems to be most severe, he said.
Near Fontana and Walworth, based on current usage, the water table around the wells has lowered anywhere from 35 to 50 feet. To the north near Williams Bay, water tables are being drawn down 5 to 25 feet.
But to the east in Lake Geneva, cones of depression around four municipal wells are just 5 feet below the groundwater table and just a few feet across.
Recharge time for ground water appears to be much faster for Lake Geneva groundwater than for water on the west side of the lake, Peters said.
Ultimately, the area will be able to support only a finite amount of water usage, called "carrying capacity," Peters said.
Carrying capacity is a policy decision as to how much groundwater can be drawn without seriously affecting the quality of life, Peters said.
"I would say we're getting close to carrying capacity," he said. "In theory, it means that the water table is dropping."
If carrying capacity is ignored, the area could run out of water, Peters said.
"Are we starting to deplete the resource? This is all still exploratory," he said.
The next step is to develop a study of groundwater flow around the lake.
The study would between $50,000 and $60,000, Peters said.
"It will involve putting in monitoring wells, and it may take several years to come up with useable data," Peters said.
