Last year, a raw April wind scattered ice pellets across the bare soil of a southeastern Minnesota farm field where Department of Natural Resources hydrologist Jeff Green assesses a bathtub-sized depression. “This is a sinkhole,” he declares with an enthusiasm that seems exaggerated for such an unremarkable-looking natural feature. But to Green this is an entry point for understanding the way water moves underground in this geologically unique corner of the state.
Lakes are absent here, but more than 700 miles of designated trout streams flow through this dramatic landscape of steep bluffs, caves, and wooded valleys. The cold water that supports trout flows from springs. In order to protect these springs from potential threats—pollution, demand for more water to irrigate farm fields, and land-use changes such as sand mining—it’s important to know where a spring’s water comes from and how it gets there.
With money from the Environment and Natural Resources Trust Fund, Green and University of Minnesota hydrogeologist Calvin Alexander recently concluded a seven-year project to map many of the region’s springsheds, or basins where springs originate. In this terrain of sinkholes and porous underground rock, that work confirmed that ground water is particularly vulnerable to contamination from poor agricultural practices, land development, and chemical spills. Most significantly, the project uncovered evidence that water deep underground is more susceptible to contaminants, such as nitrates and pesticides, than previously thought.
Fortunately, the springshed research is also leading to partnerships with counties as they look to better protect water resources.
Join us at the High Court and learn more about karst geology, spring mapping, and groundwater in southeast MN from Jeff Green himself!