The massing flooding caused by heavy rainfall in Alberta is expected to impact Saskatchewan in the next couple of days.

The Water Security Agency says record inflows from Alberta will cause flooding along the South Saskatchewan River.

The agency says more than 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.

If the forecast is correct, it will be the highest flow recorded since Lake Diefenbaker was constructed and on the South Saskatchewan River since the early 1900’s.

Typical flows for this time of year is near 500 m3/s.

As a result, the agency is increasing outflows from Lake Diefenbaker to try and mitigate the impact of this event.

The SWA says these outflows will result in some flooding of agricultural land downstream of Lake Diefenbaker and may affect municipal infrastructure near the river.

As a result of the increased releases, flow on the South Saskatchewan River below Lake Diefenbaker will be increased over the weekend from 800 m3/s to 2,000 m3/s over the weekend.

The agency says these releases will cause the river to rise roughly another two metres, which will increase the river velocity significantly.

The SWA says there is also a “major concern” on the Saskatchewan River near Cumberland House downstream of where the North and South Saskatchewan Rivers meet.

The Alberta government recently issued a high flow advisory for the North Saskatchewan River, and this — combined with high flows on the South Saskatchewan River — will cause flooding along the Saskatchewan River.

The provincial government says it has been in contact with the affected communities and is beginning the evacuation process for Cumberland House as flows are expected to reach this area next week.