Nature That Works

The report evaluates 17 types of natural infrastructure across four functional families (cover, basins, watercourses, and groundwater) to support water management in the Canadian Prairies. It argues that while natural assets like grasslands and wetlands are essential, constructed analogues such as bioretention and green roofs are necessary in urban areas to bridge the infrastructure gap. The document provides performance rankings and technical data to help decision-makers build a more robust business case for nature-based solutions over traditional grey infrastructure.

• Natural infrastructure in the Canadian Prairies is categorized into four functional families based on morphology and water quantity role: cover (vegetation/substrate), basins (surface depressions), watercourses (sloped channels), and groundwater (subsurface reservoirs).
• The Canadian Prairies have experienced significant ecosystem loss, with estimates suggesting a 40% to 70% loss of wetlands and approximately 80% loss of prairie grasslands, primarily due to urban and agricultural expansion.
• Climate change is projected to increase 'weather whiplash' on the Prairies, characterized by more frequent and intense rainfall events, lower snowpack, and hotter summers, which will challenge existing water infrastructure.
• Grasslands and forests significantly reduce runoff compared to urban or agricultural land; for example, converting grassland to urban impervious cover can increase runoff from a 100-mm rainfall event by 63.66 to 89.43 mm.
• Constructed wetlands are effective for both stormwater and wastewater treatment, with the ability to reduce BOD by 70%–90% and pathogens by 90%–99.9%.
• Bioretention systems are highly effective at treating the 'dirtiest' stormwater runoff, with reported metal removal efficiencies frequently exceeding 80%.
• Green roofs can achieve up to 97% runoff reduction in prairie settings when using deeper media (300 mm), though they may act as a source of dissolved phosphorus.
• Permeable pavements can reduce annual runoff volumes by 50% to 100% and are particularly effective at removing automotive-associated contaminants, including a 99% reduction of motor oil and diesel.
• Riparian areas provide essential water quality benefits, though their effectiveness in removing phosphorus is limited, as dissolved phosphorus and orthophosphates can often bypass physical filtration.
• A 'treatment train' approach—sequencing preservation, source control, and end-of-pipe interventions—is recommended to optimize stormwater management and protect source water.

APA

Simoes, J., van Duin, L., Skorobogatov, A., Méthot, J., Rawluk, A., & Stanley, M. (2025). Nature That Works. International Institute for Sustainable Development. https://www.iisd.org/system/files/2025-09/benefits-performance-natural-infrastructure-water-management.pdf

Chicago

Simoes, Joey, Leta van Duin, Anton Skorobogatov, Josée Méthot, Ashley Rawluk, and Madeline Stanley. Nature That Works. International Institute for Sustainable Development, 2025. https://www.iisd.org/system/files/2025-09/benefits-performance-natural-infrastructure-water-management.pdf.

Wikipedia

{{cite report |last1=Simoes |first1=Joey |last2=van Duin |first2=Leta |last3=Skorobogatov |first3=Anton |last4=Méthot |first4=Josée |last5=Rawluk |first5=Ashley |last6=Stanley |first6=Madeline |title=Nature That Works |publisher=International Institute for Sustainable Development |date=September 2025 |url=https://www.iisd.org/system/files/2025-09/benefits-performance-natural-infrastructure-water-management.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{simoes2025nature, author = {Simoes, Joey and van Duin, Leta and Skorobogatov, Anton and Méthot, Josée and Rawluk, Ashley and Stanley, Madeline}, title = {{Nature That Works}}, institution = {International Institute for Sustainable Development}, year = {2025}, month = sep, url = {https://www.iisd.org/system/files/2025-09/benefits-performance-natural-infrastructure-water-management.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }