Project Number:
WR99R016
Other Project Number:
WRI GRR 01-05
Funding Year:
1999
Contract Period:
7/1/1999 - 06/30/2000
Funding Source:
UWS
Investigator(s):
PIs:- John Jansen, UW-Milwaukee
- Robert Taylor, UW-Milwaukee
Abstract:
Background/Need:
The sandstone aquifer is the major source of municipal and industrial water in Waukesha County. The aquifer has been heavily exploited over the last century, creating a regional cone of depression that is over 500 feet deep and currently centered on eastern Waukesha County. Over the last ten to fifteen years, total dissolved solids (TDS) levels have risen significantly in several of the higher capacity municipal wells in Waukesha County. TDS levels in at least two municipal wells have risen to over 1,000 ppm. A new municipal sandstone well, in the City of Brookfield, unexpectedly encountered high TDS water (2,200 ppm), causing substantial additional expense to the water utility. While high TDS water is certainly present within portions of the sandstone aquifer, the spatial distribution of this water is poorly defined. The location and depth of high TDS water in the sandstone aquifer must be understood before the cause of the problem and potential solutions can be identified.
Objectives:
The goal of this study was to map the distribution of high TDS water in the sandstone aquifer in Waukesha and Milwaukee Counties. Direct water sampling through packer tests in existing wells or dedicated monitoring wells was prohibitively expensive. Geophysical methods offered the only practical method of mapping zones of high TDS water in the aquifer. A secondary goal of the study was to map the base of the aquifer.