A STATEWIDE INVENTORY OF SPRINGS TO BETTER UNDERSTAND GROUNDWATER SYSTEMS OF WISCONSIN

With the aim of improved management of groundwater and groundwater-dependent ecosystems, the Wisconsin Geological and Natural History Survey is inventorying springs with flow rates of 0.25 cubic feet per second (cfs) and higher. This effort is producing one of few statewide databases of springs in the country. The inventory consists of one-time surveys of individual springs and semi-annual surveys of six reference springs selected from representative geological, hydrological, and ecological regions of Wisconsin. To date, quantitative and qualitative descriptions have been recorded for over 250 springs. Descriptions include information on flow rate, location, geologic setting, geomorphic setting, and water quality. The mean flow rate of the 250 springs surveyed is 0.92 cfs; values range from 0.17 cfs to 8.69 cfs. More than 90% of surveyed springs are classified as rheocrene springs, which discharge into defined channels. About 25% of surveyed springs emerge as fracture or contact springs, and about 75% of the surveyed springs have seepage-filtration morphologies. Nearly half of the springs show evidence of moderate to high levels of disturbance, such as dredging, the presence of a spring house, recreation, or access to livestock. The majority of the highly disturbed springs are located on private land.

As regions of the state are surveyed, patterns in spring distribution and type are emerging and are related to geology and topography. Study of these patterns will improve understanding of the geologic conditions influencing preferential groundwater flow in the region. The spring inventory will aid in evaluating the potential impacts of groundwater withdrawals on Wisconsin’s water resources and provide a snapshot in time of the state of Wisconsin’s springs.