Fine sediment impacts on water treatability in fire impacted watersheds: Quantification of downstream propagation and water quality threats

森林是加拿大58%的最大城市和农村社区以及大多数土著社区的主要饮用水来源。具有讽刺意味的是，这些水资源的高质量使它们容易受到严重的大规模景观干扰，如野火造成的干扰。在过去二十年中，火灾天气条件的气候相关变化导致北美西部关键森林水源地区重大野火干扰的发生率、范围和严重程度迅速增加。野火对森林地区河流沉积物和相关营养动态的威胁可能对加拿大和全球许多地区的供水和生态系统服务构成真正的风险。尽管野火的经济和环境意义以及对提供安全饮用水的威胁，相对较少的研究已经检查了细沉积物在排放燃烧流域的河流中的传播以及这些物质向水库的输送。对于这种沉积的底部沉积物是否是磷的汇或来源，或者它是否有可能增殖生长可能挑战水处理过程的蓝藻，人们知之甚少。鉴于在加拿大和美国，落基山脉东坡以森林积雪融化为主的斜坡是关键的供水区域，从这项研究中获得的知识与水源通常来自森林景观的供水有关。研究结果将提高人们对火灾后沉积物和相关磷在大流域尺度上对河流的运输过程和水质影响的认识，并评估下游环境（如湖泊和水库）的水质风险。从拟议的研究中获得的知识将为水库管理战略提供科学见解，以评估野火引起的细沉积物对水处理的风险以及提供安全饮用水的相关挑战。

Forests are the primary source of drinking water for > 58% of the largest urban and rural communities as well as most Indigenous communities in Canada. Ironically, the high quality of these water resources make them vulnerable to severe large scale landscape disturbance such as those produced by wildfire. Climate associated changes in fire weather conditions over the past two decades have resulted in rapidly increasing occurrence, extent, and severity of major wildfire disturbances in critical forested source water regions of western North America. The threat of wildfire on sediment and associated nutrient dynamics in rives draining forested regions may pose a real risk to water supply and ecosystem services in many regions in Canada and across the globe. Despite the economic and environmental significance of wildfire and threats to the provision of safe drinking water, relatively few studies have examined the propagation of fine sediment in rivers draining burned watersheds and the delivery of these materials to reservoirs. Little is known about whether this deposited bottom sediment is a sink or source of phosphorus or if it has the potential to proliferate the growth of cyanobacteria which can challenge water treatment processes. Given that forested snow melt dominated slopes of the eastern slopes of the Rocky Mountains are critical water supply regions in Canada and the United States, knowledge gained from this research is relevant to water suppliers where source waters generally originate from forested landscapes. Results of the proposed research will improve knowledge of the transport processes and water quality impacts of post fire sediment and associated phosphorus in rivers at the large basin scale and evaluate the risk to water quality in downstream environments such as lakes and reservoirs. Knowledge gained from the proposed research will provide scientific insights to inform reservoir management strategies to evaluate the risk of fine sediment from wildfires to water treatability and related challenges to the provision of safe drinking water.