At the head of Lake Diefenbaker, which is formed by the South Saskatchewan River, you will find the Gardiner Dam, standing 64 meters high with the ability to discharge 7,500 cubic meters per second. The Gardiner Dam was the largest earth-filled dam in the world and continues today, 36 years after completion, to regulate the flow of water into the South Saskatchewan River.

The Minister of Agriculture, James Gardiner and the Prime Minister, John Diefenbaker, got together and decided to reintroduce the idea of building a dam, that would tie together with the South Saskatchewan River Project. From these two men emerged the names of both Lake Diefenbaker and Gardiner Dam. Word got out about the building of the dam and people came from far and wide to lend a hand with the construction. On May 27, 1959, construction of the dam began. At the same time, 40 kilometers southeast of Gardiner Dam another major dam project was underway. The Qu’Appelle River Dam was the smaller dam of the two, however, without it the water could easily escape and flow into the Qu’Appelle Valley. 8 years later, in 1967, both the Gardiner Dam and the Qu’Appelle River Dam were placed into operation, creating the large water basin we know today as Lake Diefenbaker. Many of the families that found their way to Saskatchewan to work on the dam remain in the area today.

Prior to 1967, residents of Saskatchewan used less than 1% of the water from the South Saskatchewan’s annual average flow. Today, drinking water from Lake Diefenbaker is used either indirectly or directly by 3 of Saskatchewan’s major centers; Saskatoon, Regina and Moose Jaw, and is well utilized by rural communities and farms, bringing the total consumption of drinking water from Lake Diefenbaker to over 45% of the province’s population!

Residents of Saskatchewan are continually faced with the possibility of drought. However, with the production of the two dams, Lake Diefenbaker and the South Saskatchewan River are able to be regulated regarding the amount of water stored and released each year. By doing this, this can ensure communities, irrigators, industry and other water users that they will have water during very dry conditions in the area.



Lake Diefenbaker boasts almost 800 kilometers of shoreline—about the distance between Regina and Calgary!



From 1959 to 1967, construction of both the Gardiner and the Qu’Appelle River dams cost about $120 million, to replace them today would cost approximately $1 billion!



Under extreme situations, the level of Lake Diefenbaker can fluctuate as much as 11 meters annually. More commonly, it rises and falls three to nine meters each year!



The Gardiner Dam spillway is more than a kilometer long and required 280,000 cubic meters of reinforced concrete!



About 94% of the water released from Lake Diefenbaker passes through the penstocks of the Coteau Creek power station to produce electricity for the province!



Evaporation is the largest consumptive use of Lake Diefenbaker water. On average, the lake gives up 345,000 cubic decameters of water to evaporation each year . . . A total comparable to losing the water from 90,000 Olympic-size swimming pools!


For more information, visit