Drinking Water Security and Climate Change Adaptation in Canada: Developing Best Management Practices for Active Source Water Protection and Treatment Resilience in Forested Watersheds

全球森林对水的自然储存和过滤价值估计为4.1万亿美元。森林及其供应的水的健康受到许多压力的威胁，包括气候变化加剧的干扰，如野火和飓风，这些干扰导致水源水质更加多变和恶化，可能会对饮用水处理厂造成超出其能力的挑战。向受纳水域输送更多的细小沉积物和营养物质(碳、磷)尤其令人担忧。溶解有机碳的波动使得在治疗期间很难最佳地使用化学混凝剂，并可能导致潜在健康后果的消毒副产品的形成增加。生物有效磷的增加会促进藻类(蓝藻)的生长；水华会降低处理过程的效率，并会产生令人不快的味道和气味或毒素。从水中去除它们需要昂贵的先进技术，这是大多数处理厂没有的，因此可能导致服务中断甚至停电。气候变化加剧的野火的频率和严重程度的增加表明，全球迫切需要在提供安全饮用水方面提高复原力--协同整合绿色(森林)和灰色(植物内)处理能力的技术-生态解决方案越来越被视为提供了这些解决方案。在加拿大，58%的大城市和大多数小系统的饮用水来自森林流域。尽管这些地区在供水方面发挥了关键作用，但它们是唯一没有将保护饮用水水源的最佳管理做法作为首要优先事项的要求或指导的主要景观。由于森林特别容易受到气候恶化的严重干扰，这项研究的目标是提供制定生物多样性管理计划所需的新的、可操作的知识和技术创新，将森林管理和水处理复原力办法结合起来，以确保饮用水安全。除了野火引起的有机碳转移和相关处理成本的增加外，自火灾以来，麦克默里堡水库中的藻类每年都会大量繁殖。2021年，它们产生毒素的能力得到了展示。现在有一个时间敏感的机会来学习这些史无前例的、具有潜在毒性的火灾后藻类水华--虽然它们是全球第一次，但不会是最后一次。建议开展实验室、中试、植物和分水岭规模的研究，以制定缓解战略，评估藻类在来源质量和可处理性方面的变化，并研究新的混凝剂和生物处理方法，以提高处理弹性。将利用多方利益攸关方伙伴关系，培训新一代工程师和科学家，开发适应气候变化的技术-生态解决方案，以确保加拿大现在和未来的饮用水安全。

The value of natural storage and filtration of water by global forests has been estimated at $4.1 trillion. The health of forests and the water they supply is threatened by many pressures, including climate change-exacerbated disturbances such as wildfires and hurricanes, which result in more variable and deteriorated source water quality that can challenge drinking water treatment plants beyond their abilities. Increased delivery of fine sediments and nutrients (carbon, phosphorus) to receiving waters is especially concerning. Fluctuations in dissolved organic carbon make it difficult to optimally dose chemical coagulants during treatment and can lead to increased formation of disinfection byproducts of potential health consequence. Elevated bioavailable phosphorus promotes algae (cyanobacteria) growth; blooms reduce treatment process efficiency and can produce unpleasant tastes and odors, or toxins. Their removal from water requires costly advanced technology not found in most treatment plants, and thus can lead to service disruptions or even outages. Increases in the frequency and severity of climate change-exacerbated wildfires have revealed an urgent global need for greater resilience in the provision of safe drinking water-techno-ecological solutions that synergistically integrate green (forest) and grey (in-plant) treatment capacities are increasingly viewed as offering those solutions. In Canada, the drinking water for >58% of the largest cities and most small systems originates in forested watersheds. Despite their critical role in the provision of water, these regions are the only major landscapes with no requirements or guidance for best management practices (BMPs) to protect drinking water sources as a primary priority. As forests are especially vulnerable to severe climate-exacerbated disturbances, the goal of this research is to deliver the new, actionable knowledge and technological innovation needed to develop BMPs that integrate forest management and water treatment resilience approaches to ensure drinking water security. In addition to wildfire-induced shifts in organic carbon and associated increases in treatment costs, algae have bloomed annually in Fort McMurray's reservoirs since the fire. In 2021, their ability to produce toxins was shown. There is a time-sensitive opportunity to learn from these unprecedented, potentially toxic post-fire algae blooms-while they are the first globally, they will not be the last. Lab-, pilot-, plant-, and watershed-scale research is proposed to develop mitigation strategies, evaluate algae-mediated changes in source quality and treatability, and investigate novel coagulants and biological treatment approaches to increase treatment resilience. Multi-stakeholder partnerships will be leveraged to train a new generation of engineers and scientists in the development of techno-ecological solutions for climate change adaptation to ensure drinking water security in Canada now and in the future.