The Decline of Water Storage in Prairie Watersheds

The document highlights the decline of natural water storage in the Canadian Prairies due to drainage and land conversion, which increases vulnerability to climate-driven extremes. It advocates for a combination of wetland conservation and constructed water retention projects to improve water security, reduce flood peaks, and enhance water quality. The brief provides specific examples of successful projects in Alberta, Saskatchewan, and Manitoba, while outlining a strategic framework for future expansion, including prioritized conservation and increased funding.

• Historical drainage and landscape alterations have severely reduced water storage in the Canadian Prairies. In Alberta, the loss of approximately 133,000 hectares of wetlands over 40 to 60 years resulted in a loss of roughly 379 million m³ of water storage capacity, which is about 21 times the volume of Calgary’s Glenmore Reservoir.
• Climate change is expected to increase the frequency and severity of droughts and floods in the prairies. Changes in precipitation patterns, such as increased winter rainfall instead of snow, may lead to decreased snowpack and lower infiltration, increasing the risk of water scarcity as demand grows from population and industry.
• Natural water retention measures, which include both the conservation of existing landscapes (floodplains, grasslands, riparian areas, and wetlands) and constructed solutions (small reservoirs), are superior to 'grey infrastructure' like dry dams because they provide long-term storage and broad co-benefits rather than just short-term detention.
• Constructed water retention projects are being implemented across the Canadian Prairies with significant results: Ducks Unlimited Canada manages 1,690 basins in Alberta holding an estimated 1.6 billion m³ of water; Manitoba's watershed districts built 257 projects between 2018 and 2023 providing 6.7 million m³ of storage; and Ducks Unlimited Canada restored drained wetlands across 3,842 acres in Saskatchewan.
• Water retention projects provide measurable environmental and economic benefits. In southern Manitoba, the Steppler Dam reduced annual peak flows from snowmelt by 72% and summer rainfall by 48%. A research site near Morden, Manitoba, showed average reductions of ~65% for peak flow, ~80% for total dissolved phosphorus, ~78% for total phosphorus, and ~82% for total suspended solids from 2016 to 2019.
• Wetlands in the prairie pothole region of Saskatchewan store an average of 205 t/ha of carbon, but 89 t/ha would be released if they are drained. While restoration can reduce carbon, it takes many years for restored wetlands to become carbon sinks.
• Economic analysis of 10 water retention projects in Southern Manitoba indicates that every dollar invested provided CAD 3.16 in co-benefits to livestock producers, while also preventing flood damage to local infrastructure.

APA

Rawluk, A., & Méthot, J. (2026). The Decline of Water Storage in Prairie Watersheds. International Institute for Sustainable Development. https://www.iisd.org/system/files/2026-01/natural-infrastructure-essentials-water-retention.pdf

Chicago

Rawluk, Ashley, and Josée Méthot. The Decline of Water Storage in Prairie Watersheds. International Institute for Sustainable Development, 2026. https://www.iisd.org/system/files/2026-01/natural-infrastructure-essentials-water-retention.pdf.

Wikipedia

{{cite report |last1=Rawluk |first1=Ashley |last2=Méthot |first2=Josée |title=The Decline of Water Storage in Prairie Watersheds |publisher=International Institute for Sustainable Development |date=January 2026 |url=https://www.iisd.org/system/files/2026-01/natural-infrastructure-essentials-water-retention.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{rawluk2026decline, author = {Rawluk, Ashley and Méthot, Josée}, title = {{The Decline of Water Storage in Prairie Watersheds}}, institution = {International Institute for Sustainable Development}, year = {2026}, month = jan, url = {https://www.iisd.org/system/files/2026-01/natural-infrastructure-essentials-water-retention.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }