Shellmouth Reservoir

Lake of the Prairies
Shellmouth Reservoir
Lake of the Prairies from the Shellmouth Dam
Lake of the Prairies is located in Manitoba
Lake of the Prairies
Lake of the Prairies
Location in Manitoba
Lake of the Prairies is located in Canada
Lake of the Prairies
Lake of the Prairies
Lake of the Prairies (Canada)
LocationR.M. of Shellmouth-Boulton / R.M. of Shell River, Manitoba and Cote No. 271, Saskatchewan
Coordinates51°08′40″N 101°30′19″W / 51.14444°N 101.50528°W / 51.14444; -101.50528
Typereservoir
Primary inflowsShell River
Primary outflowsAssiniboine River
Basin countriesCanada
Max. length56 km (35 mi)
Surface area61.5 km2 (23.7 sq mi)
Water volume480×10^6 m3 (390,000 acre⋅ft)
Surface elevation425 m (1,394 ft)
References[1]
Shellmouth Dam
An aerial view of Shellmouth Dam and Reservoir
Coordinates50°57′49″N 101°25′07″W / 50.96361°N 101.41861°W / 50.96361; -101.41861
PurposeMulti-purpose
StatusOperational
Construction began1964
Opening date1971
Construction cost$10.8 m CAD
Built byPrairie Farm Rehabilitation Administration
Owner(s)Government of Manitoba
Dam and spillways
Type of damEmbankment dam
Height (foundation)21.3 m (70 ft)
Width (crest)1,270 m (4,170 ft)
Website
gov.mb.ca/mit/wms/shellmouth/

The Shellmouth Reservoir (also known as Lake of the Prairies) is a man-made reservoir on the Assiniboine River in Manitoba and Saskatchewan, Canada.[2]

The Shellmouth Dam (50°57′49″N 101°25′07″W / 50.96361°N 101.41861°W / 50.96361; -101.41861) is a multi-purpose embankment dam built by the Prairie Farm Rehabilitation Administration (PFRA).[2]

The dam and reservoir are part of a strategy to reduce the risk of flood damage for Winnipeg and other communities along the Assiniboine River.[2] For example, in the 1997 Red River flood, the inflow to the reservoir peaked at 10,000 cubic feet per second (280 m3/s) while the outflow never exceeded 1,700 cu ft/s (48 m3/s).[3] The reservoir is also used to supplement flows on the Assiniboine when conditions are dry, ensuring water supply for Brandon, Portage la Prairie, irrigators, and some industries. For example in early August, 2021 the flow in Brandon was a little over 9 m3/s while the outflow from Shellmouth was 5.7 m3/s and inflow was less than 0.5 m3/s. Therefore without the dam the flow in the Assiniboine at Brandon would be a bit under 4 m3/s.

Asessippi Provincial Park is established around the southern arm of the lake.

  1. ^ "Manitoba Infrastructure: Shellmouth Dam and Reservoir". Government of Manitoba. Retrieved 22 November 2021.
  2. ^ a b c "Water Management and Structures | Infrastructure | Province of Manitoba". www.gov.mb.ca. Retrieved 7 August 2021.
  3. ^ "Flood Control Works". Prairiewaternews.ca. Archived from the original on 15 January 2013.