BY SUSAN SWANSON, DIRECTOR, STATE GEOLOGIST
WISCONSIN GEOLOGICAL AND NATURAL HISTORY SURVEY & UW-MADISON DIVISION OF EXTENSION

The Greater Madison Area is well known for its lakes, but the region is also rich with springs, where shallow groundwater naturally flows to the surface. The Yahara lakes and the broad wetlands that surround them, such as Cherokee Marsh or the Waubesa Wetlands, are also partly fed by groundwater. But in a spring, the groundwater emerges in a concentrated, visible form, often lifting and suspending sand from the bottom of a pool, flowing from a fracture in a rock outcrop, or even creating a stream depending on the volume of water.