National Lakes Assessment

Person in boat on lake gathering water sample in large plastic syringe.The National Lakes Assessment (NLA) is a statistical survey of the condition of our nation's lakes, ponds, and reservoirs. It is designed to provide information on the extent of lakes that support healthy biological condition and recreation, estimate how widespread major stressors are that impact lake quality, and provide insight into whether lakes nationwide are getting cleaner.

In 2017, Minnesota participated in the U.S. EPA's national lakes assessment, in collaboration with a number of partners:

  • U.S. Forest Service
  • U.S. Department of Agriculture
  • National Park Service
  • Minnesota's Departments of Natural Resources, Health, and Agriculture
  • Red Lake and White Earth Nations
  • Leech Lake and Mille Lacs Bands of Ojibwe
  • Fond du Lac Band of Lake Superior Chippewa

Nationally, the survey included 1,000 lakes; Minnesota drew 42 lakes for the statistically based survey effort and added eight lakes to allow for state-based assessment. One hundred lakes were also added from EPA’s randomized list of lakes to allow for ecoregion-based assessments (50 per major ecoregion) in Minnesota.

This collaboration and the various survey add-ons were the basis for several “value-added” topics:

  • Analysis of emerging contaminants in 50 lakes (MPCA)
  • Analysis of sediment chemistry in 30 lakes (MPCA)
  • Pesticide analysis in 50 lakes (MN Dept. of Agriculture)
  • Herbicide analysis in 150 lakes for glyphosate (MN Dept. of Agriculture)
  • Zooplankton analysis in 150 lakes (MN Dept. of Natural Resources)
  • Blue-green algal toxin (microcystin and anatoxin-a) in 150 lakes (lab analysis by MN Dept. of Health, reporting by MPCA)
  • Water chemistry and profiles in 150 lakes (MPCA)

For more details on the national study, visit the EPA web site.