面向库区段鱼类洄游保护的水量-水质耦合优化调控研究

Reservoir construction changes river flow regime and water quality, thereby threatening fish migration. Existing research on this topic mostly focused on managing water quantity and quality for protecting fish migration downstream of dams. However, complex hydrodynamic and water quality conditions in reservoirs may hinder fish migration upstream of dams, which has been rarely explored. This study aims to explore the impacts of reservoir environmental conditions on fish migration and propose a new reservoir operation method for protecting fish migration upstream of dams. First, a three-dimensional model will be developed to simulate reservoir hydrodynamic and water quality factors, such as water depth, flow velocity, temperature, transparency, and dissolved oxygen. The relations among water quantity and quality factors will be revealed through statistical analysis. Second, the response of target migratory fish to water environmental variations in reservoirs will be simulated after field investigation and reservoir environmental monitoring. The impacts of reservoir water quantity and quality variations on fish migration will be explored. According to fish migration requirements on hydrodynamic and water quality conditions, potential fish migration route in a reservoir can be determined and environmental conditions along this route will be set as the restoration target in reservoir operation. Last, a dual-objective optimization model for reservoir operation will be developed, considering both fish migration and reservoir socioeconomic benefits. By solving the model with a genetic algorithm, an optimal operation schedule will be proposed for guiding reservoir management. This study will provide theoretical support and management tools for reservoir operation to mitigate the barriers to fish migration caused by reservoir impoundment.

建坝导致的河流水文情势与水质变化严重威胁鱼类洄游。当前面向鱼类洄游保护的调控多关注大坝下游的水量与水质问题，而大坝上游库区复杂水环境对鱼类洄游的影响尚不清晰，面向库区段洄游保护的调控方法仍待探索。本项目拟揭示库区水量-水质条件对鱼类洄游的协同影响，并建立以水库调度为手段的水量-水质耦合优化调控方法。以“库区环境模拟-鱼类影响分析-水库调度优化”为主线，首先构建水库三维水动力-水质模型，模拟影响洄游的水深、流速等水量要素与温度、透明度、溶解氧等水质要素，分析库区水量-水质要素间的关系；然后通过鱼类调查与水环境监测，建立洄游鱼类对水量-水质要素变化的响应模型，揭示库区水量-水质变化对鱼类洄游的协同影响；最后分析库区段潜在洄游路径，建立兼顾鱼类洄游保护与社会经济效益的水库优化调度方法，确定权衡鱼类需求与人类利益的最佳调度方案。本项目将为缓解库区复杂水环境对鱼类洄游的阻碍提供理论参考和技术方法。

围绕河流筑坝建库的生态环境效应这一热点，系统探究了水库水量–水质的联合调控机制，建立了考虑鱼类洄游保护的水库优化设计与调度方法，丰富了耦合社会经济效益与生态环境保护多目标的水库生态调度理论与方法，成果将有助于缓解筑坝建库对河流洄游鱼类的影响，促进水利工程健康、可持续发展。首先，建立了水库水动力–水质–底泥过程耦合模型，模拟了大型水库复杂水动力与水质条件的时空变化，分析了水库水文水动力条件（如水深、流速）与水质条件（如温度、氮磷浓度、溶解氧等）间的关系，明晰了水库水量–水质多要素的耦合调控机理；然后，通过设置多种水库调度情景，评价了水库调度策略对库区水动力与水质条件的影响，重点分析了水库调度对库区氮磷物质循环过程的影响及作用机理，阐明了调度对库区水体–底泥界面有机物沉积与无机盐释放过程的影响，明确了水库水量–水质多目标间存在的协同或拮抗关系；最后，评价了变化环境下河流鱼类产卵场的空间适宜度变化，分析了水动力与水质要素变化对鱼类产卵场空间适宜度的影响，综合考虑水库社会经济效益、水质风险防控、生态保护需求等目标，构建了面向水量–水质联合调控的多目标水库调度优化模型，发展了鱼类洄游保护约束下的水库成本–效益分析框架，耦合鱼类洄游保护目标，提出了指导水库库容设计与调度优化的水文–经济–生态耦合模型。基于项目成果，目前已发表一区/二区SCI论文共7篇，获授权国家发明专利1项，培养研究生3名，研究成果将为权衡水库社会经济效益与鱼类洄游保护目标的水库设计与调度提供了理论与方法支撑。