Lake Diefenbaker Updates
Lake Diefenbaker Updates
Updated July 13, 2026
Current Conditions
-
Most headwater stations are continuing to decline. Flows in the Oldman and Red Deer rivers are now closer to median levels, while flows in the Bow River are generally closer to upper quartile levels for this time of year.
-
With the recent hot and dry weather, Alberta diversions have increased. The declining headwater flows and increased diversions are expected to contribute to lower inflows into Lake Diefenbaker over the coming days.
-
Inflows into Lake Diefenbaker are currently near upper quartile levels for this time of year. Inflows are expected to continue declining and move closer to median levels by the weekend.
-
Water levels on Lake Diefenbaker are currently near upper quartile levels for this time of year and are expected to remain near upper quartile levels throughout the week.
-
Releases from Coteau Creek Hydro Station are planned to remain near plant capacity at approximately 270 m³/s. WSA reduced the spill to approximately 100 m³/s this morning, resulting in a total release from Lake Diefenbaker of approximately 370 m³/s. The current plan is to terminate spill operations on Wednesday.
-
SaskPower’s third generating unit at Coteau Creek Hydro Station has completed its scheduled maintenance and is back online. Testing of the unit is currently underway; therefore, releases from the station may fluctuate periodically. These fluctuations, along with downstream travel time, may result in short-term variations in flows at Saskatoon.
-
Conditions will continue to be monitored closely, and outflows may be adjusted as needed based on updated forecasts and observed basin conditions.
Forecast Overview
The table shows the updated 10-day forecast for Lake Diefenbaker.
-
Inflows into Lake Diefenbaker are expected to continue declining through the forecast period and move closer to the median levels by the weekend.
-
The current total outflows are approximately 370 m³/s. Spill operations are planned to end on July 15th (Wednesday), after which outflows are expected to be maintained between 270 m³/s to 300 m³/s.
-
Lake Diefenbaker is expected to rise slightly from approximately 556.28 m to 556.33 m before levelling off and gradually declining near the end of the forecast period.
Hydrologic / Weather Conditions
- Over the weekend, the South Saskatchewan River Basin headwaters received minimal precipitation. Minimal precipitation is also forecast for the basin this week.
Below are the updated plots showing 2026 observed inflows and reservoir elevations compared to historical ranges.
An Experienced Team
We love our Saskatchewan waterways, and we also know a lot about them. If you need help finding information or determining if your shoreline or water-related project needs a permit, we can help! Use the contact form or give us a call to get started.