Lake Pepin
January 2013
Lake Pepin is a threatened natural resource with a long history of providing benefits to a wide range of citizens in Minnesota, thanks to its unique geology and position in our river system. The nature of the pollutants threatening Lake Pepin, primarily excess sedimentation, are complex and require careful and strategic attention.
The Lake Pepin Legacy Alliance (LPLA) was established in 2009 by a citizen-led committee determined to preserve and restore the lake as an integral part of the Upper Mississippi River System.
Located just south of the confluence of the Mississippi, St. Croix and Minnesota Rivers, Lake Pepin is the first stop for sediment coming from three major watersheds in Minnesota, – from this point water flows down the Mississippi River and ultimately into the Gulf of Mexico.
In the last 150 years, the amount of sediment entering and settling in Lake Pepin has increased ten-fold. Research shows that the increased rate of sedimentation is directly proportional to the increase in flow, or the volume and force of water coming from the surrounding rivers, streams, and ditch systems: the higher the flow, the higher the sedimentation rate.
As water flows from three major watersheds in Minnesota through Lake Pepin, ending finally in the Gulf of Mexico, a large “dead” zone sits at the end point. This region’s oxygen levels are so low that it cannot support aquatic life. The dead zone, also known as the hypoxic zone, varies in size each year, depending on the concentrations of nutrients, primarily nitrogen and phosphorus, being discharged into the Gulf. As with sediment, nutrient concentrations are proportional to the flow rate. The greater the volume and force of the water, the greater the sediment and nutrient loads, and ultimately the greater the impact on both Lake Pepin and the Gulf of Mexico.
The good news is that the filling of Lake Pepin can be slowed or halted, and the size of the dead zone can be diminished if efforts are made to more effectively manage our water resources by slowing down rivers in Minnesota and encouraging both ground and surface water storage. LPLA developed this website to provide up-to-date information on relevant state and federal regulations, current science, and news coverage of the issue. Further, LPLA is in the process of developing a Local Resource Management Scorecard to identify county specific conservation efforts across the watershed that contributes 75% of the sediment settling in Lake Pepin, the Minnesota River Basin. To learn more about our Local Resource Management Scorecard, click on the video below!
