TMDL study improves impaired lake shared by Canada and the US

Maximizing innovative technologies and advanced water quality science to benefit a lake of international significance.

2012 - Present
US Minnesota Border and Canada
Minnesota Pollution Control Agency (MPCA) and the Lake of the Woods Soil and Water Conservation District (SWCD)

Collaborating with the US and Canada to improve a critical water resource, RESPEC’s team was recognized for developing another successful, high-visibility environmental project with international impact. In June 2018, the International Rainy–Lake of the Woods Watershed Board presented the International Joint Commission (IJC) with a recommendation to endorse phosphorus reduction goals for Lake of the Woods, a lake that spans a border of both the US and Canada. The phosphorous reduction goals were outlined in a study that RESPEC completed on behalf of the Minnesota Pollution Control Agency (MCPA). Representing Canada and the US, the IJC endorsed and submitted the Board’s recommendations to both governments for immediate interim phosphorus reductions in the lake that covers approximately 1,500 square miles. In 2008, the waters on the US Minnesota side were declared impaired because phosphorus and algae (measured in chlorophyll a) exceeded water quality standards.

For decades concerned groups have been working together to increase the water quality of the enormous lake, shared by Minnesota and the Canadian provinces of Ontario and Manitoba. For the past 6 years, RESPEC’s Minnesota staff has played a key role in providing water science to the International Rainy-Lake of the Woods Watershed Board. The MCPA and the Lake of the Woods Soil and Water Conservation District (SWCD) hired RESPEC to conduct a Total Maximum Daily Load (TMDL) study of the resource. The Lake of the Woods Sustainability Foundation, a non-profit, also works binationally to protect the lake.

Beginning in 2015, RESPEC conducted the TMDL study and wrote the project report. The study included creating eight HSPF (Hydrologic Simulation Program – Fortran) models to represent pollutant runoff from the watershed into the lake. RESPEC’s team also created five linked lake models to represent how the lake responds to the watershed runoff. Although the study is complete, the project will continue through 2018 as the US Environmental Protection Agency (EPA) and public review cycles are completed. RESPEC’s Minnesota team led the project management, outreach, public meetings, communications, HSPF modeling, lake modeling, technical approach, and report development.

Like many of RESPEC’s cross-cultural assignments, this project required close collaboration and expert communication about a process unfamiliar to the Canadian side. Since TMDLs are a US-only requirement mandated by the Clean Water Act, which Canada doesn’t share, many Canadian colleagues were not familiar with the TMDL process. Because Lake of the Woods is an international water that flows north into Manitoba’s Lake Winnipeg, it was important that RESPEC’s Canadian partners understood and concurred with the study. RESPEC’s team worked closely with the MPCA and the Lake of the Woods SWCD, as well as the Lake of the Woods Sustainability Foundation, to develop communication and outreach materials to introduce and explain the value of TMDL studies, and impart a working level of information and knowledge.

Supporting MCPA and the Foundation, RESPEC played a significant role in establishing TMDL studies for the governments of Canada and the US as they worked together to establish a shared binational phosphorus substance objective and load reduction targets for Lake of the Woods, an important shared binational waterbody.

The IJC goals build on an impressive history of improving the Lake of the Woods basin water quality from legacy pollution. The goals secure the binational commitment to fully restore the lake and enhance the resilience of the watershed against changing climate and watershed conditions. Specifically, the International Rainy-Lake of the Woods Watershed Board recommended to IJC that:

“That the Governments of Canada, Ontario and Manitoba commit to an 18.4 percent reduction in phosphorus loads to Lake of the Woods as an interim measure at this time;

“That the Governments of Canada and the United States work together to establish a shared binational phosphorus substance objective and load reduction targets for this important shared binational waterbody; and

“That the Governments of Canada and the United States commit to regularly reviewing and revising this shared binational objective and targets as further science becomes available, with a first review as soon as possible after Environment and Climate Change Canada completes its current scientific assessment of Lake of the Woods in 2020.”

RESPEC’s successful project is applicable and of interest to many other regions in the US and abroad. While thousands of TMDL studies have been completed throughout the United States, this one was unique because the water resource covers a huge area, the lake is a binational water, and the technical approach was innovative.

TMDL reports are oftentimes years in the making and there can be a lengthy review prior to the reports becoming final and, therefore, implementable. The IJC endorsement of this report and its findings, prior to full completion of the review and approval process, means the collaborative restoration effort starts immediately.

RESPEC is very pleased to contribute effective science to the lake with a long history of international cooperation among agencies. Using advanced water quality science to address the needs of the Lake of the Woods basin ecosystem will result in greater health and eventual restoration.


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Image for Hydrologic Simulation Program‑FORTRAN (HSPF)

Hydrologic Simulation Program‑FORTRAN (HSPF)