The dam is the source of the Qu'Appelle River and it keeps the flow of water down the river relatively constant. Formerly, the Qu'Appelle River dried up in many places every summer at the conclusion of the spring freshet from the Rocky Mountains. Constant, steady flows down the Qu'Appelle River are important as downstream there are several smaller dams and reservoirs that supply water for irrigation, industry (such as the Mosaic potashmine at Belle Plaine), and drinking water for cities such as Regina and Moose Jaw. The dam is 3,100 metres (10,200 ft) long, 27.4 metres (90 ft) high, and, along with the Gardiner Dam, holds back a reservoir that contains 9,400,000 dam3 (7,600,000 acre⋅ft) of water.[4]
During the time of glaciation on North America, the retreating glacier would block the flow north and would force the water flow down the Qu'Appelle River. When the glaciers retreated further, water would then flow north. Before the Gardiner Dam was built, spring flows were high enough to allow water down the Qu'Appelle but would dry up later in the fall. Now as the Qu'Appelle Dam always retains the water of Lake Diefenbaker, water is released into the Qu'Appelle River in order to maintain flows throughout the entire year. This serves the farmers along the Qu'Appelle who use it for irrigation and watering their livestock.[5][6]
Public access to the Qu'Appelle Dam is from a scenic viewpoint that provides views of the dam itself, Lake Diefenbaker, and the Qu'Appelle Valley. A short road from Highway 19 leads to the viewpoint. Along the top of the dam runs the Canadian Pacific Railway; the dam was designed with this type of loading in mind.[citation needed]
Douglas Provincial Park (named after former premier of Saskatchewan Tommy Douglas)[8] extends from the dam to the community of Mistusinne to the north.[9][10] Lake Diefenbaker has over 800 kilometres (500 mi) of shoreline and around the lake there are many communities, parks, and recreational facilities, such as campgrounds, beaches, golf courses, and marinas.[11][12]
^Henderson, Norm. "Qu'Appelle Valley". University of Regina. Canadian Plains Research Centre, University of Regina. Retrieved 20 March 2024.
^Karpan, Robin; Karpan, Arlene (18 May 2021). "Through the Qu'Appelle Valley". Tourism Saskatchewan. Government of Saskatchewan. Retrieved 20 March 2024.