Souris River

The Souris River rises in the Missouri Coteau region of southeastern Saskatchewan, near the town of Weyburn, and flows generally southeast into North Dakota, then turns northeast back into Manitoba before joining the Assiniboine River near Treesbank.¹ The river's name derives from the French word for "mouse" (souris), a reference to the many mice once found along its banks; the river is also known as the Mouse River in North Dakota.

The river's flow is highly variable, with extreme floods and droughts. The 2011 flood, caused by heavy spring snowmelt and rain, set record water levels and forced the evacuation of Minot, North Dakota, where the river crested at 15.9 meters (52 feet).² The river is regulated by several dams, including Rafferty Dam and Alameda Dam in Saskatchewan, built primarily for flood control and water supply.³

The Souris River supports a variety of aquatic life, including northern pike, walleye, and channel catfish, and its riparian zones provide habitat for migratory birds such as the piping plover, a threatened species.⁴ The river's water quality has been affected by agricultural runoff, leading to high nutrient levels and algal blooms, particularly in the J. Clark Salyer National Wildlife Refuge in North Dakota.⁵

In 2014, a major fish kill occurred in the Canadian portion of the river, attributed to a combination of low water levels and high water temperatures, which reduced oxygen concentrations.⁶ Conservation efforts, including the Souris River Watershed Management Plan, aim to balance water use with ecological health.⁷

Indigenous peoples, including the Assiniboine and Cree, used the Souris River for transportation and fishing long before European contact. The river was later a route for fur traders in the 18th century, and the Hudson's Bay Company established posts along its course.

Today, the river supplies water for irrigation and municipal use in Saskatchewan and North Dakota. The city of Minot, North Dakota, relies on the river for its drinking water, and the river's reservoirs are popular for recreation, including boating and fishing.³ The river also has a history of flooding, with major floods recorded in 1881, 1904, 1952, 1969, 1976, and 2011, prompting the construction of flood-control structures.²

One of the river's lesser-known features is the Souris River Bend National Wildlife Refuge in North Dakota, which protects a unique oxbow of the river and is a key stopover for migrating sandhill cranes.⁵ The river also crosses the International Peace Garden, a park symbolizing the friendship between the U.S. and Canada, near the border.⁷

In 2011, the flood led to the discovery of a previously unknown archaeological site near Minot, where artifacts dating back 5,000 years were unearthed, offering new insights into early human habitation in the region.⁶ Additionally, the river's name "Mouse" is reflected in the name of the nearby town of Mouse River, North Dakota, which was renamed to Souris in 1902 to avoid confusion with the river's French name.

Missouri Coteau

A plateau region in Saskatchewan and North Dakota that forms the headwaters of the Souris River.

Oxbow

A U-shaped bend in a river that has been cut off from the main channel, often forming a lake or wetland.

Riparian zone

The interface between land and a river or stream, characterized by distinctive vegetation and wildlife.