Impaired waters viewer (IWAV)

The interactive IWAV map displays impaired waters around Minnesota in the draft 2022 Impaired Waters List.

Glossary of abbreviations used in the map


Impaired waters: Waters failing to meet one or more water quality standards.

Delisted waters: These are previously listed waters now determined to meet water quality standards based on new and reliable data. Delistings may occur as a result of watershed actions or other factors.

Corrective actions: Y = Delisting was a result of actions in the watershed that resulted in improved water quality. N = Delisting was not a result of corrective actions.

List corrections: Corrections are determinations that a water is not impaired but which are not considered delistings. Shown are all corrections to the 2022 Impaired Waters List.

AUID: Assessment unit identifier

Reservation: Defined by the U.S. Census Bureau’s 2019 spatial data on tribal lands except with respect to the Mille Lacs where the state disagrees with the tribe and the federal government on the boundaries of the reservation. See the tribal designation section in the posted draft.

Use class: See Minn. Rule 7050.0220 for definitions

Impaired uses:

  • AQC: Aquatic consumption, see Minnesota Dept. of Health for more information
  • AQL: Aquatic life
  • AQR: Aquatic recreation
  • DW: Drinking water
  • LRV: Limited resource value
  • WR: Wild rice production

TMDL: Total maximum daily load, a pollutant reduction study.

  • TMDL approved: Impairments for which a TMDL plan has been approved by the U.S. EPA at the time this map was updated.
  • TMDL not required: Caused by non-pollutants or reflect natural background conditions.
  • Additional impairments: Impairments for which a TMDL is underway or not yet developed.


  • Ace: Acetochlor
  • Al: Aluminum
  • Amm-U: Ammonia, unionized
  • As: Arsenic
  • Cl-: Chloride
  • Clpyr: Chlorpyrifos
  • Cu: Copper
  • DDT (Dichlorodiphenyltrichloroethane)
  • Dieldrin
  • Dioxin (including 2,3,7,8-TCDD)
  • DO: Dissolved oxygen
  • E. coli: Escherichia coli (E. coli)
  • FC: Fecal coliform
  • FishesBio: Fish bioassessments
  • Hg-F: Mercury in fish tissue
  • Hg-W: Mercury in water column
  • InvertBio: Benthic macroinvertebrate bioassessments
  • Nitrate
  • Nutrients
  • PCB-F: Polychlorinated biphenyls (PCBs) in fish tissue
  • PCB-W: Polychlorinated biphenyls (PCBs)
  • PFOS-F: Perfluorooctane Sulfonate (PFOS) in fish tissue
  • PFOS-W: Perfluorooctane Sulfonate (PFOS)
  • pH
  • PlantBio: Aquatic plant bioassessments
  • SO4: Sulfate
  • T: Turbidity
  • Temp: Temperature
  • Toxaphene
  • TSS: Total suspended solids