Saskatchewan's Water Security Agency is advising that record inflows from Alberta will cause flooding along the South Saskatchewan River.
Based on the current rainfall in Alberta, over 6,000 cubic metres per second (m3/s) are estimated to arrive on the South Saskatchewan River into Lake Diefenbaker and estimated to peak on Monday. This will be the highest flow recorded since Lake Diefenbaker was constructed and on the South Saskatchewan River since the early 1900s. Typical flows for this time of year is near 500 m3/s.
In anticipation of these record flows, the Water Security Agency is proactively increasing outflows from Lake Diefenbaker to try and mitigate the impact of this event. These outflows will result in some out-of-bank flooding of agricultural land downstream of Lake Diefenbaker and may affect municipal infrastructure near the river.
As a result of the increased releases, over the weekend flow on the South Saskatchewan River below Lake Diefenbaker will be increased from 800 m3/s to 2,000 m3/s. These releases will cause the river to rise roughly another two metres, which will increase the river velocity significantly.