Accounting for Environmental and Life Safety Risks of Reservoir Releases in Regulated Watersheds: Reservoir and Land Management

水库外流和大坝溃决造成重大洪水风险，并对下游经济和生命安全造成相关影响。这些系统形成的人工湖和引起的极端或受管制的河流流量可能造成不可逆转的环境破坏，并威胁水生生态系统。周边地区的土地使用做法可能会对流域水文和住区格局产生影响，并释放非点源污染物，从而加剧这种风险。鉴于可能造成严重后果，需要有方法提供合理和透明的基础，以便在面临气候变化和其他不确定性的情况下评估这些风险，并在水库运营和流域管理决策中考虑到这些风险。本项目：i）推进水质模型，以确定下游环境影响及其与鱼类种群和栖息地的相互作用，水库外流，并制定措施，估计这种后果的风险; ii）制定水库运营决策框架，考虑气候和土地使用变化面临的环境，渔业和生命安全风险;以及iii）发展方法，以解释在估计土地使用的环境和洪水后果时的不确定性。所开发的模型和方法将用于确定受风险影响的程度，说明系统在短期或长期内从风险中恢复的能力，在后果可能不可逆转时发出信号，并说明降水模式和土地使用做法的变化。它们可用于支持水库系统的规划和运作以及区域参与性用水规划进程。 研究结果将直接有利于电力和水务公司管理其风险组合，并保持其经营许可，并对区域用水管理人员和社区，因为他们评估各种水和土地利用的好处之间的权衡和水资源短缺，环境破坏和系统水文变化的成本。 它们将加强对大型资产的负责任管理，并改善公共安全和环境质量。这些都是加拿大各级政府的持续优先事项。**

Reservoir outflows and dam failures pose significant flood risks with related downstream economic and life safety impacts. The artificial lakes formed and extreme or regulated river flows induced by such systems may cause irreversible environmental damage and threaten aquatic ecosystems. Land use practices in the surrounding region may exacerbate such risks through their effects on watershed hydrology and settlement patterns, and the release of non-point source pollutants. Given the potential for severe consequences, methods that provide rational and transparent bases for assessing such risks in the face of climate change and other uncertainties, and accounting for them in reservoir operating and watershed management decisions are needed. This project: i) advances water quality models for identifying downstream environmental impacts and their interactions with fish populations and habitat, of reservoir outflows, and develops measures for estimating the risk of such consequences; ii) develops a reservoir operating decision-making framework that considers environmental, fisheries, and life safety risks in the face of climate and land use change; and iii) develops methods that account for uncertainty in estimating the environmental and flooding consequences of land uses. The models and methods developed will be designed to identify the degree of exposure to the risks, characterize the ability of a system to recover from them in the short- or long-term, signal when the consequences may be irreversible and account for changes in precipitation patterns and land use practices. They may be used to support the planning and operation of reservoir systems and regional participatory water use planning processes. The findings will be of direct benefit to power and water utilities in managing their risk portfolio and maintaining their permission to operate and to regional water use managers and communities as they evaluate tradeoffs between the benefits of the various water and land uses and the cost of water shortages, environmental damage, and changes in system hydrology. They will enhance responsible management of large assets and improve public safety and environmental quality. These are ongoing priorities for all levels of government in Canada. **