WSA Increases Flows from Gardiner Dam, South Saskatchewan River Expected to Rise
The Water Security Agency (WSA) has announced a significant increase in outflows from Gardiner Dam at Lake Diefenbaker and will begin operating spillway gates to release additional water from Lake Diefenbaker in response to recent heavy precipitation in Alberta and rising inflows into the reservoir.
Starting June 7, outflows are expected to increase from approximately 280 m3/s to around 700 m3/s. Peak releases are anticipated around June 11, followed by a gradual reduction over the following week.
For context, typical flows for this time of year are around 160 m3/s, meaning current and upcoming releases are well above seasonal norms.
River levels expected to rise
The increased discharge will lead to noticeable rises along the South Saskatchewan River, including:
- Approximately 1.4 metres through the Moon Lake area
- Approximately 0.6 metres in Saskatoon
While WSA does not anticipate out-of-bank flooding at this time, river levels and flow velocity will increase significantly.
Operational response to upstream conditions
WSA says the decision reflects a cautious operational approach following:
- A large rainfall event in southern Alberta this week
- Rapid increases in headwater flows on the South Saskatchewan River system
- Forecasts of above-normal mountain runoff expected through mid-to-late June
- Rainfall warnings issued by Environment and Climate Change Canada across parts of southern Alberta
The agency notes that additional adjustments to outflows remain possible depending on incoming conditions.
Safety warning issued
With spillway operations underway, WSA is urging the public to stay well clear of Gardiner Dam and to maintain a safe distance from all associated works.
Downstream, the South Saskatchewan River between the dam and Saskatoon will experience higher velocities, increasing risks for recreational users and anyone near or in the water.
WSA is advising the public to exercise extra caution and carefully assess any activities around waterways during this period.
Ongoing updates
WSA will continue to provide updates on Lake Diefenbaker operations as conditions evolve.
More information: https://wsask.ca/recreation-environment/lake-diefenbaker-updates/