Every two years, MPCA creates a list of impaired waters that do not meet water quality standards. Learn more: Defining impaired waters.
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2020 Impaired Waters List
On March 26, 2021, EPA partially approved and partially disapproved Minnesota’s 2020 Clean Water Act (CWA) 303(d) list of impaired waters that require establishment of a total maximum daily load (TMDL) to attain water quality standards. EPA approved the list of waters identified by Minnesota as consistent with Section 303(d) of the CWA and EPA’s implementing regulations. EPA disapproved Minnesota’s decision not to list any waters as impaired due to exceedances of the State’s sulfate criterion to protect wild rice because existing and readily available data and information indicate impairments of that criterion.
EPA is seeking comments on its identification of 30 water quality limited segments (WQLSs) impaired for sulfate, which it's proposing to be added to Minnesota’s 2020 List of Impaired Waters. Comments must be submitted by June 30, 2021. After considering public comments and making appropriate revisions, EPA will transmit the final list to Minnesota. For details on the 30 WQLSs and how to comment go to EPA’s website.
Describes Minnesota's monitoring and assessment strategy, assessment tools, and the redesigned assessment process. The purpose of this guidance is to define the required data and information and lay out the criteria by which waterbodies are assessed to determine if beneficial uses are supported.
The comment period for the 2020 Impaired Waters List and assessment guidance manual was open Nov. 12, 2019, through Jan. 14, 2020.
- Public comments on Minnesota's 2020 Impaired Waters List (wq-iw1-65f)
- Responses to public comments received on the 2020 Draft Impaired Waters List (wq-iw1-65ga)
See the Impaired Waters Viewer (IWAV) for all impaired waters, including those just listed, delisted, and corrected for the new list.
Also known as the 305(b) Integrated Report, combines two requirements of the Clean Water Act to report to Congress on the quality of Minnesota's waters.
For GIS professionals: Go to MPCA's spatial data webpage to download shapefiles on Minnesota's impaired waters.