To sustain our nation's lakes, we need to know their current health and the impacts of various stressors. The northern half of Minnesota, Wisconsin and Michigan, or the Northwoods, is home to 50% of the natural lakes in the U.S. The clean, clear lakes are what make it a great place to live and draw visitors from all over the world. These lakes are an amazing natural and economic resource - their value can't be calculated.

Stressors that have been identified for the Northwoods are: climate change, excessive algae growth, nutrient loading and color. This project monitored 250 randomly-selected lakes across the Northwoods as an intensification of the EPA National Lake Assessment (NLA) in 2022. The goal was to compare them to each other to understand patterns and stressors within the Northwoods but then to also compare them to the larger, nationwide survey of lakes within the NLA lakes nearby and around the country.

To accomplish this huge task, we organized and jointly sampled these lakes with the help of partners from:

• 5 national forests
• 3 states' regulatory agencies
• 1 county soil and water conservation district
• EPA national and regional staff
• 2 National Park Service units
• 8 tribal bands and authorities
• 5 universities
• Cooperation of numerous lakeshore owners that allowed our crews to access the lakes

The benefits of all this information will enable management of lake resources to produce the greatest good for the public, who highly value them. This effort will also establish a baseline in time for comparison purposes. Preliminary results from the project will be presented.

¹ USDA Forest Service, Duluth, MN

² Minnesota Pollution Control Agency, Duluth, MN

³ University of Wisconsin - Trout Lake Station, WI

⁴ Michigan Department of Environment, Great Lakes, and Energy, East Lansing, MI

* Corresponding Author: trent.wickman@usda.gov