Blog and banner photo by Watershed Stewardship Assistant, Maria Albuquerque
Spring is making its way to our watershed, with warmer days and more birds chirping. It is also the time of year when we start to look into the water forecast. The Oldman watershed’s drought stage has lowered to level 1 as precipitation has increased, which helped keep most of our reservoirs with good water levels. Water advisories are in place, but the Water Sharing Agreement may not be activated this year. While our reservoirs are in better shape than last year, more snow will be critical for our watershed’s water supply, and using water wisely remains essential!
Current Conditions
Drought Stage 1
Since November, the Alberta Drought Stage in our watershed has been lowered to Stage 1: Monitoring and Observing. This time last year we were on stage 4: Significant drought conditions in multiple water management areas. During stage one, the Water Supply Outlook indicates that we may not meet water management thresholds and that there is a higher chance of senior water license holders making a priority call. Drought conditions have improved, not only in our watershed but also in other parts of Alberta and Canada.
The Canadian Drought Monitor maps from March 2024 (top) and February 2025 (bottom) show drought intensity in various regions of Canada. Last year, Alberta had extreme drought conditions in March in many parts of the province. This year, there are fewer spots where drought is present, varying from ‘Abnormally dry’ to a small area with ‘Severe drought’ conditions. The arrow indicates the Oldman watershed. Adapted from Agriculture and Agri-Food Canada (2024, 2025).
High Precipitation & Low Snow Accumulation
Since November 2024, we have received more precipitation than during the same period last year. This has helped to keep more than half of our reservoirs within the average water level range and to rehydrate the soil, alleviating drought conditions in our watershed.
Precipitation maps from the winter months of 2023-2024 (top) and 2024-2025 (bottom). The darker green colors on the 2024-2025 map show that we have accumulated more precipitation than in 2023-2024. Adapted from Alberta’s River Forecast Centre.
However, while we received more precipitation in the prairies, snow accumulation is lower compared to last year. As of March 1, mountain snowpack accumulation in the Oldman watershed is below to much below average, ranging from 59% at South Racehorse Creek to 77% at Gardiner Creek snow stations (see image below). The snow water equivalent in millimeters calculated in the watershed ranges from 55 at Lee Creek (86 last year) to 467 at Gardiner Creek (506 last year), showing that some parts of the watershed have more snow water than others. This scenario may change depending on how much snow we can still accumulate in the mountains before double-digit temperatures are sustained.
Top image: Snow water equivalent (snow pillow) in the South Racehorse Creek (blue) is below the normal range (purple), and below last year’s snow pillow (red). Bottom image: Snow water equivalent in Gardiner Creek is below last year’s snow pillow but within normal range.
Reservoir Levels
The average water level in all fifteen reservoirs in our watershed is 69.5%—a significant increase from last year. The Oldman and St. Mary reservoirs currently sit at 55% and 51%, respectively, compared to 32% and 15% last March. However, it is important to note that out of 15 reservoirs, six are still below the normal range, including the Oldman.
The water levels in the four major storage reservoirs in the Oldman watershed (Oldman, Waterton, St. Mary, and Pine Coulee Reservoirs) as of April 2nd compared to levels in March 2024, and the normal range for this time of the year. The red circles outline the reservoirs. Infographic by Maria Albuquerque.
Stream Flow
Currently, the flow level of the Oldman River at a station near Lethbridge is at 18.52 m³/s (cubic metres per second). This is a little below the normal flow range for this time of the year, but we may soon begin to see an influx of water coming through the Oldman River near Lethbridge as snow melts in the mountains and we receive any spring precipitation.
Calculated flow and water level for the Oldman River near Lethbridge (Alberta Rivers App).
Soil Moisture
On April 1st, 2025, current soil moisture reserves (i.e., previously fallen precipitation stored in the ground) are normal to high for most of the Oldman watershed, with some moderately low levels near the County of Warner area. Alberta Rivers highlights that while current moisture levels are good, they may not substantially alleviate the moisture deficits caused by the multi-year drought.
Water Shortage Advisories & Water Sharing Agreements
A water shortage advisory covers the Oldman watershed's water management areas of Castle River, Pincher Creek, Upper Oldman River, Willow Creek, Crowsnest River, and Lee Creek shown in purple. Map adapted from Alberta Rivers.
As of April 1st, 6 Water Shortage Advisories have been in place in the Oldman watershed since last season. Usually, the advisories remain during winter/early spring months, so we may see updates depending on how much water we receive in the next couple of weeks.
The current conditions of most reservoirs and soil moisture indicate a better water supply than last year. With that in mind, according to local irrigation districts there will not be a Water Sharing Agreement this year. This agreement, implemented last year to ensure more water efficiency in the southern tributaries, may not be necessary this season since reservoir levels are significantly higher and soil moisture appears favorable. Around this time of the year (early spring), the irrigation districts typically discuss how much water producers can allocate based on the weather and water supply forecast. Find more information on the SMRID website.
La Niña Advisory
La Niña conditions are present according to the National Oceanic Atmospheric Administration (NOAA). This means there are temperature anomalies in the Tropical Pacific Ocean, which bring colder and wetter conditions to the north of North America. This has led to more precipitation in our watershed. NOAA predicts that ENSO-neutral (neither La Niña nor El Niño) will likely develop in the next month and persist through June-August 2025.
Water Forecast & Its Implications
Let it Snow (a bit more)
In addition to the ENSO-neutral forecast for the next season, as of February 28, Environment Canada forecasted above-normal temperatures for March through May 2025 and normal precipitation for southern Alberta. May, June, and July are considered the most important months for receiving precipitation in Alberta.
Our watershed predominantly depends on snowmelt from snowpacks for its water supply. As of March 1st, the mountain runoff predictions are much below average for the March-September period. University of Calgary’s Tricia Stadnyk, Canada Research Chair in Hydrologic Modelling, warns that snowpack levels are concerningly lower than this time last year in Southern Alberta. She highlights that snow accumulation is critical for filling our reservoirs and keeping our stream flow levels within normal range. The more snowfall we receive this month, the more we can guarantee our water supply for the following months.
Waterton National Park. Photo by Maria Albuquerque
Let’s Be Water Wise
While we hope for more snow in the mountains, we should remain vigilant about our water usage. As outdoor water use increases in late spring to early fall, we can continue to follow water-smart recommendations and keep an eye on the forecast. Living in a semi-arid watershed means that water conservation is necessary throughout the entire year.
Conclusion
To conclude, reservoirs and soil moisture look good for this time of the year. However, mountain runoff forecast is predicted to be below average, and snowmelt substantially impacts filling our reservoirs, lakes, and other waterways for the summer/fall season. We should still receive more precipitation, in the form of rain and/or snow, before the end of the month, and by May and June we will have a better idea of our water supply for the following seasons. In the meantime, let’s continue to use water wisely and keep our watershed healthy.
