River Report #10 - Oldman River Still Struggling Despite Rains
A calm South Saskatchewan River at Medicine Hat Wednesday evening. (Photo Alex McCuaig)
The early summer rains which hit southern Alberta last month were a relief but not enough allow for increases of water allocations on the St. Mary and Lethbridge Northern irrigation districts.
While the Bow and Red Deer Rivers were the primary beneficiaries of the widespread precipitation even over the first weekend of summer, challenges continue on the Oldman.
“It is important at this time to conserve water where possible. Water that is being used at this point is going to directly impact next year’s irrigation allocation,” cautioned an update posted on the Lethbridge Northern Irrigation District (LNID) website. “In a way, you are using next year’s water.”
LNID’s water allocation is tied to storage levels at the Oldman Reservoir and its associated Keho Reservoir to convey water to its nearly 200,000 irrigated acres in its district.
The district’s goal articulated earlier this year is to see the Oldman Reservoir at 55 per cent capacity at the end of the growing season.
While the June rains saw gains in storage at the Oldman Reservoir which had begun to fall, levels have once again begun to drop.
As of July 3, the reservoir is standing at 65 per cent of capacity with most other directly related irrigation storage on Oldman River being rated as below normal.
LNID intends to keep water allocations to irrigators at 14-inches per acre foot.
St. Mary River Irrigation District (SMIRD) is also looking at holding the line on its water allocation at 12-inches per acre foot.
SMRID’s latest update notes Alberta Agriculture and Irrigation is continuing to divert flows from the Waterton and Belly River diversion canals to add storage to the St. Mary Reservoir.
“This is a direct effort to allow all obligations to be met throughout the irrigation season,” reported SMIRD in its June 27 update.
Irrigators closer to the Bow River are fairing better with reservoir largely in the normal range.
Though, the current situation across southern Alberta rivers is likely to continue the debate as to timing of expanding irrigated acres.
In its Spring 2025 newsletter, the Bow River Irrigation District (BRID) outlined some of those concerns.
“Some irrigators have expressed concern about the reduced allocation per acre as the district has expanded, and there is a perception that we use to have enough licensed allocation to guarantee 24 inches of water for every acre,” read the newsletter released in April. “The reality is that although prior to 2002 we did not have any on-farm water use limit, followed by a 24-inch limit until 2020, when it was reduced to 20 inches, the licensed allocation was insufficient to provide that amount to each parcel.”
Post 2002, the province placed a moratorium on new water licenses on southern Alberta rivers. BRID noted infrastructure upgrades including turning open canals into underground pipelines has seen the district provide water to more acres as well as conservation projects.
A February BRID plebiscite saw district irrigators approve further expansion by a vote of 124 to 90 with more irrigated acres anticipated to be available for the 2027 growing season.
A bean crop under irrigation begins to flower Wednesday at a Medicine Hat farm. (Photo Alex McCuaig)
Streamflows on the South Saskatchewan River is anticipated to continue on its downward trend following hitting a peak last week.
The South Saskatchewan at Medicine Hat fell below its water conservation objective this week and as of July 3 is running at 153 cubic meters per second (m³/s).
The Oldman River at the forks with the Bow is running at 23 m³/s and anticipated to remain around those levels over the next week.
Contributions to the South Saskatchewan streamflows at the forks will likely be dependent on the Bow River which is at 96 m³/s Thursday morning.
Statistics for the South Saskatchewan River at Medicine Hat for July 3
Upper quartile – 632 m³/s
Lower quartile – 213 m³/s
July 3, 2024 – 341 m³/s
July 3, 2025 – 153 m³/s
Statistic for the Oldman River at Lethbridge for July 3
Upper quartile – 272 m³/s
Lower quartile – 50 m³/s
July 3, 2024 – 29 m³/s
July 3, 2025 – 21 m³/s
Statistics for the Bow River at Calgary for July 3
Upper quartile – 273 m³/s
Lower quartile – 148 m³/s
July 3, 2024 – 221 m³/s
July 3, 2025 – 129 m³/s
*Upper and lower quartile averages are based on data collected between 1911 and 2024.
Oldman Reservoir for July 3 level (metres above sea level)
Upper quartile – 1118.362 m
Lower quartile – 1117.182 m
July 3, 2024 – 1117.328 m
July 3, 2025 – 1109.990 m