River Report #6 South Sask. River Hits Record Low for June
The South Saskatchewan River on Monday following the waterbody hitting a record low streamflow for June since records started in 1911. (Photo Alex McCuaig)
The South Saskatchewan River at Medicine Hat fell to a record low streamflow this past week, falling to 30 metres per second for the first time in June since records began in 1911.
The last time the river was this low – during what is traditionally the wettest month of the year – was 1992 as the Oldman Reservoir was being filled for the first time following commissioning of the dam.
While 1992 saw the South Saskatchewan fall to a low of 37 m³/s, by the middle of June that year the river had rebounded to over 600 m³/s.
The previous low streamflow record for the river at Medicine Hat came in 1926 at 33 m³/s, according to federal hydrometric data spanning information collect for more than 110 years.
Again, 1926 saw streamflows rebound to over 600 m³/s by the middle of June.
The river at Medicine Hat is heading toward topping 100 m³/s Thursday with a large upstream release from the Bow River earlier this week flowing into the city.
Streamflows on the South Saskatchewan River at Medicine Hat are on the rise after hitting a record low for June. (Graphic courtesy Gov. of Canada, hydrometric data)
Irrigation reservoir levels are normal to above normal along the Bow and Oldman basins with notable exceptions. The Oldman and Keho reservoirs are both at below seasonal norms for this time of year at 68 and 89 per cent capacity. Both reservoirs convey water into the Lethbridge Northern Irrigation District (LNID).
LNID set the water allocations to farmers at 14-inches per acre at its April 16 board meeting. According to the district at that time, LNID stated its expectations for what they hope will be the situation on the Oldman Reservoir at the end of the growing season.
“The target is to be close to the current 55% of full in the Oldman Reservoir at the end of the irrigation season if we have a somewhat dry year, recognizing that there is room to use some of this storage if we experience an exceptionally dry year,” read the April notice.
Helping the precipitation situation in southern Alberta was the forecast for rain in the southwestern quarter of the province coming through with accumulations of 10 to 20mm over the first two days of the month.
The South Saskatchewan River was in the red for much of the past week, failing to meet its instream objective and continuing to not meet water conservation objectives. That situation is expected to change over the next seven days. (Graphic courtesy of Alberta Environment)
But what’s increasingly in short supply is wide-spread showers across the region to capitalize on the early seeding completion, the accompanying strong emergence of crops and to provide relief to the current stresses on river ecosystems.
Such wide-spread precipitation is not in the forecast over the next seven days.
Temperatures are expected to not be excessive with highs in the mid-20s to low-30s and overnight lows in 10- to 13-degree range across the region.
Streamflows on the South Saskatchewan River at Medicine Hat are on the rise following significant bumps in upstream releases with that situation likely to continue through the weekend.
The Bow River at the forks has seen streamflows rise from a June 1 low of 13 m³/s to 89 m³/s Thursday morning.
But behind that bump from the Bow will be another sag in contributions from the Oldman. Upstream communities such as Lethbridge saw a seven-day streamflow rate peak at 34 m³/s on June 2.
As of Thursday morning, the Oldman River at Lethbridge is sitting at 26 m³/s.
The Oldman River basin is in Stage 3 drought conditions, (severe drought) while the Bow River Basin is in Stage 2 (moderate drought).
South Saskatchewan River basin is at Stage 0 with adequate water supply.
