Drinking water in southern Wisconsin is supplied by an underground aquifer. (Graphic: City of Chilliwack, BC)

Aquifer Drawdown
Our drinking water in southern Wisconsin is drawn from an aquifer contained deep underground in a layer of sandstone called the Mt. Simon Aquifer. This aquifer receives its water from rain water that (in some cases over the course of thousands of years) percolates through pervious surfaces until it reaches the aquifer. This replenishing of the aquifer is referred to as groundwater or aquifer recharge, and it is the only way that the aquifer is provided fresh water.

As we continue to grow as a community, we put an increasing strain on the fresh water that this aquifer provides. Unchecked consumption will eventually result in a diminished water supply for future generations. According to the US Geological Survey, "Prior to...large-scale pumping and diversion associated with development, the lakes and wetlands within the Madison area primarily received ground water. These lakes and wetlands primarily lose water to the ground-water system as a result of present-day pumping and diversion." This is referred to as aquifer drawdown.



Aquifer Resources Downloads

• US Geological Survey report regarding aquifer-related issues and water usage in southern Wisconsin
• "Groundwater and Surface Water Interactions in Dane County" slideshow by Ken Bradbury, a hydrogeologist with the Wisconsin Geological and Natural History Survey & UW Extension

In Madison, most household and municipal wastewater is sent to MMSD's Nine Springs Wastewater Treatment Plant, where the water is treated and discharged to Badfish Creek, then the Rock River, then the Mississippi River, and ultimately the Gulf of Mexico. The importance of this is that this water does not recharge the aquifer