University of Wisconsin - Extension

Contact: Kevin Masarik, (715)346-4276, kmasarik@uwsp.edu

Stevens Point, Wis.—It’s one of Wisconsin’s most valuable resources. But it’s also one of the least understood.

"Because people don’t usually see groundwater, it’s become a very misunderstood resource", says Kevin Masarik, groundwater educator for the University of Wisconsin-Extension. "Common misconceptions that people have can make it difficult to understand the real issues and manage groundwater wisely."

Groundwater Awareness week, March 9-15, is a good time to take a closer look at this important resource.

Not as mysterious as people sometimes think, groundwater originates as rain and melting snow that infiltrates into the ground. As the water seeps into the ground, it sometimes carries with it chemicals that are applied or spilled on the land’s surface.

The water travels through soil and empty places between rocks until it reaches a zone called the water table. All of the water below the water table is groundwater.

The geologic materials--sand and gravel, sandstone, dolomite, or crystalline bedrock--that transmit and store groundwater are referred to as aquifers.

Groundwater is always moving, generally at a very slow rate, through the pore spaces or cracks in the rocks below us. The rate of movement depends mostly on the type of aquifer that holds the groundwater.

Groundwater typically moves from higher elevations called recharge areas to lower elevations, often referred to as discharge areas. Most of Wisconsin’s lakes, rivers, streams and wetlands are examples of groundwater discharge areas. Simply put these are areas where the land surface meets the water table. Recharge areas don’t have obvious surface features associated with them, and in fact, most of Wisconsin’s land surface acts as recharge areas.

In addition to supplying water to surface waters, groundwater is also the source of water for nearly three-quarters of Wisconsin’s residents and many of Wisconsin’s most important industries. Everyone with a well on their property relies on groundwater to supply water to their home or business. The same is true for the thousands of cities and villages across the state that obtain their water through municipal wells.

The well’s depth, the types of soil, and the type of aquifer into which the well is drilled, determine how long the water being pumped has been in the ground. Often, the water may have been in the ground for a year or two though some water may have been present for a decade or two. In some areas of the state with shallow soils overlying fractured bedrock, water from the land surface may reach a well in a matter of days or even hours.

Because groundwater is a local resource, any chemicals that are spilled or applied to the land’s surface have the potential to contaminate the groundwater supply below.

With so much of the state relying on groundwater, it is important that citizens do their best to protect the quality of this vital resource. Take extra care to ensure that land use activities do not pollute water supplies, particularly near municipal and private wells. Wellhead protection (limiting or restricting the types of land-uses allowed near wells), is an important tool that communities can use to protect their groundwater supply.

For more information about groundwater in Wisconsin, visit http://dnr.wi.gov/org/water/dwg/gw/pubs/atqagw.pdf for answers to some common questions.