River Report #7 - Number of Record Low Streamflows Spreading Across Southern Alberta
A large sandy beach with vegetation growth is visible on Wednesday on a stretch of the South Saskatchewan River usual underwater in June. River levels are expected to drop further going into the weekend. (Photo Alex McCuaig)
The need for rain in southern Alberta is becoming greater as dryland farms, pastures and river ecology that rely on high June precipitation levels have yet to receive their usual drenching.
According to the June 3 Alberta Agriculture crop report, seeding of cereal crops has been all but totally completed in the south region with emergence being reported at 94 per cent – well above both five and 10-year averages.
The report also outlined the issues with the recent lack of precipitation, comparing the situation to recent drought years.
“Both surface and sub-surface moisture conditions have continued to decline week over week across the province as the. spring precipitation has been limited with conditions (the week of June 3) similar historically to the conditions experienced in 2022 and 2023,” stated the report. “As seen in those previous years, June rains can result in significant improvements to soil moisture.”
As the traditional wettest month for the region continues to withhold its annual bounty, the impacts are being seen on southern Alberta waterways with multiple record low streamflow levels being reported.
On Thursday, the Bow River station at the forks with the Oldman is reporting its lowest streamflow level ever on this day since records began at the site in 1964. Multiple tributaries into both the Bow and Oldman are also seeing the same over multiple days in a row.
And the record daily low streamflows are now being seen on the Red Deer River near Bindloss, just upstream from where it joins the South Saskatchewan River as well as the Oldman River upstream of its namesake dam.
Medicine Hat is also seeing its lowest streamflow levels for June since records began in 1911.
As of Thursday morning, the South Saskatchewan River at the Hat is in the bottom 10th percentile of average.
Alberta Agriculture’s rainfall map for the month of May displaying variance from normal precipitation percentages.
The situation has seen a rise in the number of water shortage advisories with all three contributors to the Oldman reservoir – Castle, Crowsnest and upper Oldman rivers – receiving the designation.
Currently, there are six water shortage advisories along the Oldman River basin, three on the Bow and four on the Red Deer River. Across the province, there are 35 in total.
A weather system moving into the province from the south Thursday is expected to bring showers with accumulations of up to 25 mm falling along the Eastern Slopes and foothills and about half that on the southern prairie region.
Scattered showers can be expected over the next week from Red Deer to the US border but a widespread timely rain is not in the forecast. Temperatures are anticipated to be moderate, ranging from the low to high 20s with the hottest region expected to be in southeastern Alberta.
The past week saw only a few pockets of reported precipitation around Calgary, Cypress Hills, Foremost area with accumulations of under 5mm. Areas around Oyen and the Special Areas saw a little bit more.
A slow and low South Saskatchewan River makes it way through Medicine Hat Thursday morning. (Photo Alex McCuaig)
Apart from the Oldman, southern Alberta’s largest irrigation reservoirs are reporting seasonally normal storage levels. That includes Lake McGregor, St. Mary, Travers and Lake Newell.
The Oldman reservoir is currently sitting at 68 per cent of capacity.
The City of Lethbridge is promoting that municipality’s preparations for the event its water rationing action plan will be required to be activated.
The city’s current status is set at voluntary conservation.
The Oldman River basin is currently rated by the province as being in a Stage 3, severe drought and the Bow basin is in a Stage 2, moderate drought. The South Saskatchewan basin was updated this week from adequate water supply to Stage 1, abnormally dry.
