Souris River

Template:Short description Template:Redirect Template:Infobox riverThe Souris River (Template:IPAc-en; Template:Langx) or Mouse River (as it is alternatively known in the U.S., a translation of its French name) is a river in central North America. Approximately Template:Convert in length, it drains about Template:Convert in Canada and the United States.

Rising in southern Saskatchewan in the Yellow Grass Marshes north of Weyburn, the river wanders southeast into the U.S. through North Dakota beyond Minot to its most southern point at Velva, and then back north into Canada in southwestern Manitoba.

File:Highway 9 Souris Valley 03.jpg

Saskatchewan Highway 9 in the upper Souris River Valley

Flowing east, it passes through the communities of Melita, Hartney, Souris, and Wawanesa, Manitoba, prior to the confluence with the Assiniboine River near Treesbank, about Template:Convert southeast of Brandon. The main tributaries of the Souris in Manitoba are the Antler River, Gainsborough Creek, and Plum Creek. The elevation at the confluence is approximately Template:Convert above sea level.

At the end of the last ice age, over 10,000 years ago, the rapid draining of former Glacial Lake Regina eroded a large channel that is now occupied by the much smaller contemporary Souris River.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Also, much of the drainage basin is fertile silt and clay deposited by another former glacial lake, Lake Souris.

Flow rates and flood potentialEdit

During the period from 1930 to 1941 severe drought conditions prevailed and PFRA constructed four stock watering dams. In 1937 the Snyder and Ross Dams were built near Melita. In 1938 the Napinka Dam was built and the Hartney Dam was built in 1941. These were all stop log dams with a total capacity of Template:Convert. The Souris Dam was originally built in 1911 and was rebuilt in 1935. The Wawanesa Dam was completed in 1951 storing about Template:Convert of water.

Most of the annual flow of the Souris River comes from snow melt and spring rains. The annual flow volume varies dramatically from Template:Convert in 1937 to Template:Convert in 1976. It is expected that the total runoff for 2011 at Wawanesa will exceed Template:Convert about a one in 500-year event. The average annual runoff is equivalent to 3 mm over the entire Souris River watershed.<ref>Archived data from Water Survey Canada</ref>

Two large dams in Saskatchewan, Rafferty Dam and Grant Devine Dam were built, in part, to reduce flood peaks on the Souris River.

In summer 2011, a historic flood affected much of the Souris River basin, overtopping levees and causing the evacuation of about 11,000 residents in Minot as well as significant damage to farmland and other property along the length of the river.

The channel capacity of the river in Manitoba varies from about Template:Convert near the border, to about Template:Convert through Melita, to about Template:Convert near Lauder and Template:Convert near Hartney. North of Hartney the capacity increases to more than Template:Convert. The drop between the border and Hartney is only about Template:Convert.

Location	1882 Peak Flow (cfs) (Estimated) <ref>Template:Cite journal</ref><ref>{{#invoke:citation/CS1\|citation	CitationClass=web }}</ref><ref>{{#invoke:citation/CS1\|citation	CitationClass=web }}</ref><ref>{{#invoke:citation/CS1\|citation	CitationClass=web }}</ref>	citation	CitationClass=web }}</ref>	citation	CitationClass=web }}</ref><ref>{{#invoke:citation/CS1\|citation	CitationClass=web }}</ref><ref>{{#invoke:citation/CS1\|citation	CitationClass=web }}</ref>
Minot	22,813.3<ref>Converted from 646 (m³/s)</ref>	9,350	26,900
Westhope	18,500<ref>Estimated from graph</ref>	12,400	30,400
Melita	30,017.5<ref>Converted from 850 (m³/s)</ref>	21,300	26,800
Souris	N/A	24,800	28,200
Wawanesa	39,905.6<ref>Converted from 1130 (m³/s)</ref>	26,200	27,800