Assessing the Impact of Active Land Management in Mitigating Wildfire Threat to Source Water Supply Quality

The vast majority of surface water supplies in Alberta originates in forested regions of the province, and supports approximately 94 municipal utilities, 208 communities, and 67% of the provincial population. These surface water supplies are highly vulnerable to contamination inputs and changing water conditions associated with wildfires. A provincial scale risk analysis framework is being used to investigate the magnitude and likelihood of wildfire occurrence in source water regions to evaluate the potential for altered water quality and quantity. The initial analysis identified which forested regions and which municipal drinking water treatment facilities are most at risk from wildfire. The efficacy of several current and potential landscape treatments to mitigate wildfire threats, along with the likely outcome of these treatments on mitigation of potential impacts of wildfire to drinking water treatment, are being modeled. A Monte Carlo modeling approach incorporating wildfire regime characteristics is used to simulate the ignition and growth of wildfires and generate outcome distributions for the different mitigation strategies. Cumulative changes in water quality at large river basin scales are being modeled and linked to water treatment impacts with the Soil and Water Assessment Tool (SWAT). A critical foundation of this approach is the close interaction of a large, trans-disciplinary team of researchers capable of integrating highly diverse issues of landscape wildfire dynamics, cross-scale water supply issues, and their linkage to downstream risks to drinking water treatment engineering.