Lake Pepin

Newsletter Signup

Lake Pepin (2013)

Lake Pepin is a threatened natural resource with a long history of  providing benefits to a wide range of Minnesota and Wisconsin’s citizens, 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.

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.

Source: National Oceanic and Atmospheric Administration

Source: National Oceanic and Atmospheric Administration

As water flows through Lake Pepin and into 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 in 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 Minnesota rivers and encouraging both ground and surface water storage.

We developed this website to provide up-to-date information on relevant local, state, federal, and non-government actions that are contributing to the reduction of sediment and nutrient pollutants in Minnesota, that have the potential to restore Lake Pepin, and that work toward sustainable water resource management.

For more information about the activities of the Lake Pepin Legacy Alliance, send an email to and request to be added to our quarterly newsletter mailing list.