River Report #13 - Bow, South Sask. Rivers Flowing Strong.
Boaters experience a decent current along the South Saskatchewan River at Medicine Hat Friday, something of a rarity this year which has seen record low streamflows coming into the summer. (Photo Alex McCuaig)
Significant precipitation across southern Alberta in the past week is resulting in above normal streamflows across the Bow and South Saskatchewan river basins.
But those rains which hit the region have only managed to put the Oldman River basin into average seasonal conditions, though, the waterbody’s namesake reservoir has managed to recoup five per cent of capacity lost earlier this month.
As of Friday afternoon, the Oldman reservoir is sitting at a little more than 62 per cent capacity, still below normal for this time of year.
Rains over the past week were most intense west of Calgary with more than 100 mm being recorded in some areas near the city. The Eastern Slopes between Waterton and High River recorded around 75 mm. The southeastern corner also saw significant regional rainfall in parts with areas along the Hwy. 36 corridor south of Brooks fairing best with around 40 mm, Medicine Hat receiving over 20 mm but the city of Lethbridge to the County of 40-Mile only barely breaking double digits.
The wet July comes following a particularly dry June which resulted in record low streamflows across many southern Alberta rivers.
The rains have come too late for farmers in parts of the southeastern corner of the province with the Cypress County issuing a state of agricultural disaster. The dry conditions coming into the month has seen the southwestern corner’s County of Pincher Creek put the municipality into its Stage 1 water restrictions. Those restrictions currently only pertain to non-essential water use such as those for lawns and ornamental gardens.
Outside of those regions, some farmers are experiencing issues related to too much water, specifically lentil cultivators who are seeing some weather-related diseases emerge. Though, other pest outbreaks such as grasshoppers have been curbed by the damp weather.
Soil moisture across the south region have remained stable with improvements to surface levels reported while sub-surface numbers have been reduced.
Reservoir levels across the largest irrigation reservoirs fed by the Bow River are reporting above seasonal averages.
But issues along the Oldman and St. Mary river reservoirs are seeing some continued storage level challenges which have been ongoing since 2023.
Despite the recent rainfall, the Oldman and South Saskatchewan river basins remain at Stage 3 of the provincial water supply categorization chart, indicating they are both in a severe drought status. The Bow basin remains at Stage 2, moderate drought.
Boaters along both the Bow and South Saskatchewan rivers can expect good conditions to continue of the next several days. Streamflows on the Bow at Calgary are near 200 cubic metres a second as of Friday with the South Saskatchewan River at Medicine Hat reporting 450 cubic metres a second.
Statistics for the South Saskatchewan River at Medicine Hat for July 25
Upper quartile – 277 m³/s
Lower quartile – 95 m³/s
July 25, 2024 – 65 m³/s
July 25, 2025 – 483 m³/s
Statistic for the Oldman River at Lethbridge for July 25
Upper quartile – 89 m³/s
Lower quartile – 25 m³/s
July 25, 2024 – 25 m³/s
July 25, 2025 – 40 m³/s
Statistics for the Bow River at Calgary for July 25
Upper quartile – 181 m³/s
Lower quartile – 118 m³/s
July 25, 2024 – 153 m³/s
July 25, 2025 – 187 m³/s
*Upper and lower quartile averages are based on data collected between 1911 and 2024.
Oldman Reservoir for July 25 level (metres above sea level)
Upper quartile – 1117.651 m
Lower quartile – 1115.142 m
July 25, 2024 – 1115.142 m
July 25, 2025 – 1109.190 m
Past River Reports