Heavy Rainfall Leads to Re-opening of Gardiner Dam Spillway

The Water Security Agency (WSA) will begin operating the spillway at Gardiner Dam this week following significant rainfall across Alberta that has dramatically increased inflows into Lake Diefenbaker.

Beginning July 2, outflows from Gardiner Dam will increase from approximately 270 cubic metres per second (m3/s) to 470 m3/s. On July 3, releases are expected to increase again to approximately 770 m3/s as spillway operations begin.

Current plans call for spillway operations to continue until approximately July 25, after which outflows will gradually be reduced back to 270 m3/s. WSA notes that additional increases could become necessary if more rainfall occurs or inflows into Lake Diefenbaker continue to rise.

See Live Level/Discharge Data

You can view live data from hydrometric stations on the South Saskatchewan River and across the entire province here.

Well Above Normal Flows

Typical outflows from Gardiner Dam at this time of year are around 160 m3/s, meaning the planned releases will be significantly higher than normal.

Current inflows into Lake Diefenbaker are expected to reach approximately 2,000 m3/s, compared to a seasonal average of about 400 m3/s.

The increased releases are expected to raise water levels by approximately:

• 2 metres through the Moon Lake area.
• 0.8 metres along the South Saskatchewan River in Saskatoon.

River currents will also become significantly faster as water moves downstream.

Public Asked to Use Extreme Caution

WSA is urging residents and visitors to be careful around the Gardiner Dam and to keep a safe distance from the structure.

The agency also warns that the South Saskatchewan River from Gardiner Dam downstream to Saskatoon will experience higher water levels and much stronger currents, creating potentially dangerous conditions for anyone using or near the river.

Boaters, paddlers, anglers, swimmers, and anyone recreating near the river should carefully assess conditions before entering the water.

Motorists travelling across Gardiner Dam are reminded to obey all traffic laws and watch for pedestrians.

Stay Informed

WSA will continue monitoring conditions and adjust outflows if necessary as weather and inflows change.

For the latest updates on Lake Diefenbaker operations, visit:

https://wsask.ca/recreation-environment/lake-diefenbaker-updates/

For additional information, contact the Water Security Agency at 1-866-727-5420.