Resilience and risk management in urban water supply: assessing the potential contribution of alternative systems

背景全球城市供水部门面临着巨大的挑战，以满足日益增长的需求，从枯竭的资源。虽然气候变化和城市化逐渐加剧了这些挑战，但自然和人为灾害等破坏性事件的频率也在上升。加拿大各城市迫切需要投资，以更新老化的供水基础设施，而魁北克南部最近发生的事件突出表明，不灵活的供水系统易受冲击。提出了使水源和基础设施多样化的战略，以提高城市供水系统的复原力，即通过以废水或雨水/雨水为基础的分散式替代供水系统。由于集中式基础设施的遗留问题，AWS的集成导致了集中式和分散式系统的共存。这种混合系统创造了更多的相互联系，这是知之甚少：模型需要检查集中式系统和UWS的弹性AWSs的影响。目标和方法该计划将产生尖端的科学和分析方法，结合最先进的定量风险评估方法和建模，以支持在自然和人为压力和冲击下改善城市供水的风险管理和恢复力。通过HQP培训（3名博士和4名硕士），将开发模型来模拟混合系统，并比较不同风险情景下UWS从源头到龙头的弹性。大蒙特利尔地区（GMA）是作为一个研究区域窝藏几个城市关注供水弹性，但本研究探讨了在全球范围内的模型和研究结果的理论意义。考虑了供水风险的两个维度：（i）水量，缺水风险（WS）和（ii）水质，因水质不佳而造成的公共健康风险（PH）。定量微生物风险评估将用于评价饮用水或替代水中参考病原体/指示物的感染概率。蒙特卡罗模拟将用于计算集中式与混合式UWS在不同压力情景下的WS和PH风险。该计划通过专家合作，在城市规模的跨学科工作方面实现了统一。它提供了（i）一个急需的混合模型，对于理解不同风险情景下AWS对供水恢复力的影响至关重要，（ii）关于主动适应、短期/中期和长期冲击应对的工具和指导，以及对决策者的沟通支持。模型和结果是根据全球海洋环境状况评估的需要量身定制的，但也可适用于其他城市，并有助于气候和抗灾能力等更广泛的领域，预计可应用于涉及关键基础设施的其他部门。

BackgroundThe global urban water sector faces colossal challenges in meeting growing demands from depleted resources. While climate change and urbanization gradually exacerbate these challenges, the frequency of disruptive events such as natural and man-made disasters also rises. Investment is urgently required in Canadian cities to upgrade aging water infrastructure, while recent events in Southern Quebec highlighted the vulnerability of inflexible water systems to shocks. Diversifying sources and infrastructure is put forth as a strategy to increase resilience of urban water systems (UWSs), namely through decentralized alternative water systems (AWSs) based on wastewater or rain/stormwater. With a legacy of centralized infrastructure, integration of AWSs results in the co-existence of centralized and decentralized systems. Such hybrid systems create increased interconnections, which are poorly understood: models are needed to examine the impact of AWSs on centralized systems and on UWSs' resilience. Objective and approachThis program will generate cutting-edge science and analytical approaches incorporating state-of-the-art quantitative risk assessment methods and modeling in support of improved risk management and resilience in urban water supply under natural and anthropogenic pressures and shocks. Through HQP training (3 PhDs and 4 MScAs), models will be developed to simulate hybrid systems and compare the resilience of the UWS from source to tap under different risk scenarios. The Greater Montreal Area (GMA) is used as a study region harboring several municipalities concerned with water supply resiliency; yet this study explores the theoretical implications of the models and findings at a global scale. Two dimensions of the water supply risk are considered: (i) water quantity, the risk of a water shortage (WS) and (ii) water quality, the public health risk (PH) from exposure to inadequate water quality. Quantitative Microbial Risk Assessment will be used to evaluate the probability of infection derived from reference pathogens/indicators in drinking or alternative water. Monte Carlo simulations will be used to calculate WS and PH risks under different pressure scenarios on centralized vs. hybrid UWSs. ImpactThis program is unifying in terms of working across disciplines at the city scale through expert collaborations. It provides (i) a much needed hybrid model, critical to understanding the impact of AWSs on water supply resilience under different risk scenarios, (ii) tools and guidance on proactive adaptation, short/medium and long-term shock responses and communication support to decision makers. Models and results are tailored to the needs of the GMA but can be adapted to other cities and contribute to the broader fields of climate and disaster resilience with foreseen applications in other sectors involving critical infrastructure.