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20年里，与气候相关的火灾天气条件的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、范围和严重程度迅速增加。野火对河流排水林区的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。尽管野火对经济和环境具有重要意义，并对安全饮用水的供应构成威胁，但相对较少的研究研究了细颗粒泥沙在排出被烧毁的集水区的河流中的传播以及这些物质向水库的输送。关于这种沉积的海底沉积物是磷的汇还是来源，或者它是否有可能促进蓝藻的生长，从而对水处理过程构成挑战，人们知之甚少。鉴于落基山脉东坡的森林积雪融化为主的斜坡是加拿大和美国的关键供水地区，从这项研究中获得的知识与水源供应商有关，这些水源通常来自森林景观。拟议研究的结果将增进对大流域范围内河流火灾后沉积物和相关磷的输送过程和水质影响的了解，并评估湖泊和水库等下游环境的水质风险。从拟议研究中获得的知识将为水库管理战略提供科学见解，以评估野火造成的细小沉积物对水的可处理性的风险，以及对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.