The beautiful Rainy River – a restoration success story

Special to the Times
Kelli Saunders

For those living in the central portion of the watershed, the Rainy River is a majestic landmark that has a wealth of history and significance attached to it, not to mention beauty!

For the ecosystem as a whole, it is the most influential tributary to Lake of the Woods, contributing about 70 percent of the total water flowing into the lake.

This week, we take a look at a bit of the fascinating history of the cleanup of the Rainy River – which has had a direct impact on the health of Lake of the Woods.

In the 1800s, Alexander Mackenzie called the Rainy River one of the finest rivers in the North West.

As newspapers became more popular leading up to World War 1, the river was seen as a perfect location for a paper mill and two were built on either side of the river in Fort Frances, ON and International Falls, MN.

The ensuing discharge of pollutants from the paper-making process from the 1920s to the 1960-70s had a drastic impact on the river’s health – large quantities of wood chips, fine particulate matter and organic compounds led to what’s seen (and what’s not seen) in these photos – shocking amounts of wood fibre mats downstream of the mills in 1952.

Sewage and other domestic wastes added to the mix. By the late 1950s, pollution of the Rainy River was dire enough for both Canada and the United States to bring in the International Joint Commission to study the problem and, ultimately in 1966, to establish an international pollution board for the river to pressure the governments to make much needed changes.

From this point in time, steep declines in pollutants occurred, total phosphorus being one of them.

In 2011, Kathryn Hargan, in a research project supported by the Lake of the Woods Water Sustainability Foundation, estimated that the two largest sources of phosphorus to the Rainy River are Rainy Lake and the Little Fork River.

Point sources include seven municipal sewage treatment plants and, at the time, the two pulp and paper mills. The two mills at the time were the largest human source of phosphorus to the Rainy River at about 16 percent.

Phosphorus concentrations generally increase in a downstream direction in the Rainy River due to additional non-point sources from agricultural runoff and erosion.

Even with all this, the total phosphorus loads to the Rainy River have declined dramatically since the 1960s.

Recent data from the Minnesota Pollution Control Agency (MPCA, 2014) show 86 percent decreases in total phosphorus and 75 percent decreases in Total Suspended Solids between 1953 and 2010.

In data collected by Environment and Climate Change Canada, the number of times that water quality criteria was exceeded for total phosphorus declined from 68 percent for the period between 1979-1985 to 19 percent for the period between 2009 and 2011.

MPCA is planning a public event in the borderland this summer to present findings of their most recent Rainy River study and to recognize their long-standing local partners in monitoring and protecting the Rainy River. Stay tuned for details!

This series is provided as part of the International Watershed Coordination Program of the Lake of the Woods Water Sustainability Foundation. This story has been adapted from a longer article entitled “The Rainy River- A Case Study in Pollution and Recovery” by Bev Clark, at

Kelli Saunders, M.Sc., is the International Watershed Coordinator with the Lake of the Woods Water Sustainability Foundation.