Where are we now?

Map of the Otter Tail River watershed.

Step 1: Monitoring

Step 1: Monitoring is complete!

Monitoring started in 2016 and wrapped up after the summer of 2018.

25 lakes were sampled for Phosphorus and related parameters, on top of the 75 lakes that monitor Phosphorus and related parameters on a yearly basis, as part of the Coalition of Lake Associations through RMB Environmental Labs.

12 sites on streams were monitored for water chemistry. It includes chemicals like Dissolved Oxygen, E. coli, Nitrate, pH, Total Phosphorus, and Unionized Ammonia.

84 lakes were sampled for fish community health. This assessment measures the health of the fish community against an expected community from similar lakes across the state.

21 stream sites were sampled for fish and bug community health. This assessment measures the health of the fish and bug community against an expected community from similar streams across the state.

Results from currently running sampling programs, such as the Watershed Pollutant Load Monitoring Network and the Ambient Groundwater Monitoring Network, were added to the sampled results.


An assessment was completed for these monitoring results in 2019. See report here.

Map of the Otter Tail River watershed.

Step 2: Assessment

Step 2: Assessment is complete!

Much of the assessment phase is done in office, with few results to show. Most of the reports and results are revealed in Phase 3: Reporting. Below are some assessment results I can share.

In 2019 an assessment report was completed.

A Nitrogen Infiltration Risk Map was completed to help assess groundwater concerns, see photo on the right.

Local and state agency staff completed an Implementation Survey to identify important actions in the watershed. See here for the questions and accompanying information.

For those stream reaches or lakes that are in need of improvement, MPCA and DNR prepared documents that highlight the issues and recommend strategies to counteract those issues. These are called Stressor ID reports, because the try to identify and tackle the environmental stresses that cause these poor water quality conditions. There are two reports: the Otter Tail Stressor ID Report- Streams and Otter Tail Stressor ID Report- Lakes.

Step 3: Reporting

Step 3: Reporting

We are finishing Step 3: Report.Since all of the monitoring and assessments are complete, it is now time to compile the information and create several reports that outline the issues in waters that don't meet water quality standards and outlines practices to prevent pristine waters from getting worse. These include the TMDL and WRAPS documents, which are prescribed by federal and state standards (see these links for more information, but be warned, they can be pretty technical.)

Using results from the Otter Tail Stressor ID reports for both the Streams and Lakes, Monitoring and Assessment results, implementation survey, and numerous other sources a DRAFT TMDL and WRAPS report have been created! These documents are still in the very preliminary stages and undergoing internal review with the SWCDs, state agencies, and even EPA. They should be available to view later this year.

Map of the Otter Tail River watershed.

A report about the health of fish in bugs in streams in the watershed was released July 2019. This report rates the fish and bug (also called macroinvertebrate) communities sampled in selected streams. The communities sampled in 2018 and 2019 were compared to similar stream reaches across the state. Overall, the streams in the watershed are doing great! There are some localized issues, but of the 21 streams sampled, only 5 had communities that were less robust than similar streams across the state.

This Stressor ID report was used to identify useful actions and locations within the watershed to help improve fish and bug communities. These results were used to help identify actions in the final TMDL and WRAPS documents.

Map of the Walker Lake watershed.

A report about the health of fish communities in lakes in the watershed was released March 2020. This report rates the fish communities sampled in selected lakes since 2012. Overall, the lakes are also doing great! Of the 86 sampled lakes, only 12 lakes have poor fish communities.

The issues ranged in severity and causes. Some typical candidate causes include:

  • Eutrophication- Inputs of excess nutrients from various possible sources can create detrimental changes to plant communities, changing habitat for vegetative dwelling species and sight feeding predatory fish
  • Physical habitat alteration- riparian lakeshore development and aquatic plant removal can reduce the abundance of habitat and reduce the spawning success of some fish species
  • Altered interspecific competition- Invasive species can disrupt the abundance of native species through competition or predation
  • Temperature regime changes- rising water temperature from climate change can create stress for fish species, especially coldwater fishes
  • Decreased dissolved oxygen- climate change and excess nutrients can reduce the amount of oxygen in a waterbody, thereby reducing fish survival and reproduction

See left image for an example for Walker Lake.

Map of the Otter Tail River watershed.

A final report showing all the impairments in the watershed is forthcoming. This report will identify all the impairments and try to find potential solutions to the issues causing them. This step is prescribed the the federal TMDL process and has several requirements that make this document very technical and precise. See the image left for some draft information.

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