Lake Wahtopanah

Lake Wahtopanah
Lake Wahtopanah
Location	Rural Municipality of Daly / Rural Municipality of Saskatchewan, Manitoba
Coordinates	50°03′55″N 100°10′20″W / 50.06528°N 100.17222°W / 50.06528; -100.17222Coordinates: 50°03′55″N 100°10′20″W / 50.06528°N 100.17222°W / 50.06528; -100.17222
Type	Artificial lake
Catchment area	1,260 sq mi (3,300 km2)
Basin countries	Canada
Max. length	6 mi (9.7 km)
Max. width	2,000 ft (610 m)
Surface area	1,580 acres (6.4 km2)
Max. depth	50 ft (15 m)
Water volume	24,500 acre⋅ft (30,200,000 m3)
Surface elevation	1,536 ft (468 m)

Lake Wahtopanah, also known as Rivers Reservoir, is a lake on the Little Saskatchewan River near the town of Rivers, Manitoba. Its dam was built by the Prairie Farm Rehabilitation Administration in 1960 to supplement water supplies for irrigation. It also provides the water supply for the town of Rivers, stock watering and recreation. The reservoir is about 2,000 feet (610 m) wide and six miles (10 km) long. The deepest point is about 50 feet (15 m). Riparian flows are regulated by a four-foot square gated conduit. High flows pass over a 110-foot (34 m) wide concrete chute spillway. The reservoir stores about 24,500 acre-feet (30,200,000 m³) and covers an area of about 1,580 acres (6.4 km²). The drainage area is about 1,260 square miles (3,300 km²) and extends well into Riding Mountain National Park. The province maintains a park and campground on the west shore. The name is an alternate form of the Native word watopapinah meaning "canoe people".^[1]

In late June and early July 2020, the area received a 1 in 1000 year runoff event; the flow peaked at about 300 cms (10600 cfs) . The area received over 20 inches of rain over a 5-day period causing the lake to flood to the never before seen level of 471.02 meters (1545.35 feet above sea level), 2.85 meters (9.35 feet) above the full supply level. This also caused the Manitoba Government to lose confidence in the dam and to warn everyone down stream of the likelihood of dam failure and catastrophic flooding. It caused nearby municipalities and the City of Brandon to declare states of emergency and the City of Brandon to put over 2000 residents on evacuation notice. Several near by cabins, homes, and campers in seasonal campground were lost. Once the flood waters receded, the province was able to assess the dam and regain confidence in the structure.

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