This is blog #8 in our "Understanding Drought" series, where we dive deep into Alberta's current drought situation. Keep an eye on ABWater.ca for more blogs, videos, and the latest information.
Blog written by Maria Albuquerque.
The weather has been all over the place since we last checked the forecast for our watershed in our May blog. If you think we had more rain this year than the last one, you are right! In addition to more precipitation, two Water Sharing Agreements were activated this season in the Oldman watershed to get us through the drought; both factors have been critical to supporting our water supply and ensuring nobody has to go without water.
Municipalities surpassed their target for water use reduction, and irrigation districts also majorly reduced water use for this growing season. Because of these critical efforts, reservoir levels are much higher than this time last year. While we celebrate the good news, rivers and creeks in the Oldman watershed are still experiencing low flows, and significant efforts to conserve water in our semi-arid region could be the “new normal.” In the meantime, La Niña is expected, and wetter days are ahead!
Throwback to Warmer Days: Summer Review
This summer, the Oldman watershed experienced above-normal average temperatures and above-to-normal average precipitation. We had highs of nearly 40 degrees and rain in the middle of August, a special event for Southern Alberta. As many people probably noticed, we had much more rain this year than last. Since January 2024, the total precipitation in Lethbridge has been 407.4 mm, while in 2023, for the entire year, we received almost half that, 257 mm. We combined a few graphs to show how much precipitation Southern Alberta received from May to August in 2023 and 2024 and how this impacted soil moisture.
Precipitation maps from the summer months of 2023 (on the left) and 2024 (on the right). The darker green colors on the 2024 map show that we accumulated more precipitation than in 2023. Adapted from Alberta’s River Forecast Centre.
Soil moisture as of August 2023 (top) and July 2024 (bottom). In 2024, soil moisture was moderately low to near normal in most of the Oldman watershed, shown by the circled area, a significant difference from last summer's soil moisture. This increase in moisture means crops require less water from irrigation.
A Close-up Look at our Reservoirs
Two of the major reservoirs in the watershed have more water than last year during this time of year, as shown in the image below. As of October 18th, the ten reservoirs in the Oldman watershed are, on average, at 70% total capacity, compared to 50.3% in November, 2023.
The water levels in the four major storage reservoirs in the Oldman watershed (Oldman, Waterton, St. Mary Reservoirs, and Pine Coulee) comparing November 2023 to October 2024 and the normal range for this time of the year. Infographic by Maria Albuquerque.
Although the reservoir levels are generally higher than last year's, we are still in the low range of normal levels. As of October 17th, the Oldman, Waterton, and St. Mary Rivers' levels are slightly below the normal range for this time of year. With above-normal temperatures and low water levels, including completely dry creeks, signs of drought have persisted in our watershed.
Beaver Creek dried out at the Piikani Nation on October 3, 2024. Photo by Maria Albuquerque.
Water Advisories & Agreements
At the beginning of the summer, the Oldman watershed was in water management stage 4 (multiple management areas affected); now, it has been lowered to stage 2 (active management). There are fewer water management areas with low water levels, but overall, stream flows are not meeting the water management thresholds, increasing the risk for the aquatic environment and water users.
Due to low stream flows, as of October 17th, there are 6 Water Shortage Advisories in place in the Oldman watershed. The advisory recommends licensees to review the conditions of their licenses, and often the government pauses Temporary Diversion Licences (TDL) when an advisory is in effect (a TDL allows holders to divert surface and/or ground-level water from water bodies temporarily as opposed to a permanent water license).
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.
Many Hands Make Light Work
A reminder of all the places the Oldman River and tributaries supply. Water use in our watershed has many different purposes, and in times of low levels, it is everyone’s responsibility to reduce water use - from irrigation to householders! Created by Maria Albuquerque via Canva.
This growing season, the Government of Alberta (GOA) and the major water users of our watershed worked closely to reduce water use in the region. Since its creation in April 2024, the Water Sharing Memorandum of Understanding has been voluntarily signed by the major users of the Bow, Red Deer, Oldman River, and the southern tributaries. The GOA considered it the largest water-sharing agreement in the province's history. The only two agreements activated were the Oldman River and Southern Tributaries. From May to October, representatives from irrigation districts, municipalities, and commercial industry met biweekly to discuss actions and plans to use water most effectively. WaterSMART was hired to facilitate the meetings, and the GOA shared all the data and information needed for the discussions.
This collective work was a success, and the major water users significantly reduced their water use. The St. Mary Irrigation District reported a reduction of 50% in water use, and municipalities reported a 10-25% reduction compared to last year (exceeding the 10% MOU commitments). This is a great achievement for water conservation and for the first time this type of voluntary agreement has been put in place. While irrigation districts have shut down for the season and are preparing for winter, municipalities will continue encouraging residents to reduce water use voluntarily.
The memorandum of understanding is only effective until December 31, 2024, but could be a model for the future. Depending on how much moisture we accumulate over this winter season, the successful solutions applied this summer by the major water users could become the new standard way to manage our limited water supply.
Wetter Days: La Niña Is On Her Way
After experiencing drier and warmer seasons due to El Niño, the National Oceanic and Atmospheric Association (NOAA) says La Niña is predicted to start soon. With the tropical Pacific surface water temperature below normal, La Niña is expected, bringing above-average precipitation and below-average temperatures until March 2025. A colder and wetter winter is expected for Southern Alberta, hopefully bringing more snowfall to increase our water levels.
Rain, Snow, or Shine: Welcome to Semi-Arid Southern Alberta
As residents of a semi-arid climate and drought-prone region, water shortages are more common here than in other climate regions. As extreme weather events like droughts are becoming more frequent, significantly reducing water use may be our “new normal”.
The world’s arid regions. Southern Alberta is part of the semi-arid region that extends to central Mexico. Right here in our watershed, we have a similar climate region to central Africa! Adapted from United Nations Environment Program (2007).
Water stress occurs when water consumption is higher than water availability. The Oldman watershed is at high risk of water stress shown in red. Source: Aqueduct—Water Risk Atlas (2024).
The successful collaborative work done through the Water Sharing Agreement process taught us that together we can reduce our water use quickly when we need to. By continuing to implement strategies and solutions to use water effectively in our dry region will ensure we can support our economy, society, and environment, providing us with more resilience in dry years.
Oldman River in Lethbridge with a fisherman on the right and a great-blue heron on the left. Photo by Maria Albuquerque.
Thanks to the great work done by the Oldman River’s and southern tributaries' major water users, water levels and soil moisture increased this year, ensuring water supply during the entire growing season. Continuing to work together to reduce water use is our best solution for long-term water security in our drought-prone watershed.
