River level returns to normal, reservoirs filling

Flow in the South Saskatchewan River has doubled in early July, putting the level back into the normal range for the first time since May.

However, new water supply forecasts still predict “much below average” levels of major rivers in southern Alberta, including the Bow, Oldman and Milk.

That comes after rain returned late in June and reservoirs upstream of the Hat are nearing capacity after managers put priority on holding back water this spring to recover from a dry 2023 and potential drought again this year.

The recorded flow at Medicine Hat earlier this month was about 350 cubic metres per second – about halfway between the normal high and low historical readings for the first week in July.

In a typical year the river would have begun receding after the third week in June, but this year began gaining on the Canada Day long weekend. Flow was as low as 150 cubic metres per second on Saturday, June 30.

The difference translates to roughly 1 metre, about three feet, in actual river level at the Medicine Hat monitoring station downtown.

That came just as reservoir managers reported they had nearly fully stocked their reservoirs, according to provincial water storage data provided by Alberta Environment.

On the Oldman system, the largest reservoirs were nearing capacity, including the Oldman (94 per cent), Lake McGregor (95), St. Mary’s Reservoir (89), Travers (100) and Waterton (93).

Similarly, large water bodies on the Bow River were near top level, including Lake Newell (94 per cent), Cascade (97) and Crawling Valley (97), with the exception being the large Spray Reservoir at the Three Sisters Dam (61).

Cumulatively, those reservoirs represent about three-quarters of the total storage capacity on each river system.

Earlier this month, the St. Mary River Irrigation District raised its allocation to members by one-inch per acre, to nine in total, while the Eastern Irrigation District downgraded its water conservation measures, allowing six inches per acre to be transferred from alternate parcels on top of its standing 18-inch allotment.