水电梯级开发对长江中游重要鱼类生境累积效应及调控机制研究

The cascade hydropower development has changed the natural flow regimes and also influenced river sediment, water temperature, and water quality and river landscape conditions. Then it leads to fish habitat mutation. It is very important that reducing the negative effect on fish habitat conditions. From the perspectives of protecting the habitat conditions of four major Chinese carps at the spawning grounds in the middle of Yangtze River, the key ecological factors of fish spawning are determined by analyzing the conditions of the hydrology, hydraulic, water quality and river morphology during fish’s spawning period. The cumulative effects of the cascade hydropower stations in the upper of Yangtze River on the eco-hydrological regimes and the important fish habitat conditions are assessed quantitatively with a new approach of eco-hydrology and eco-hydraulic. The physical habitat simulation model of the spawning grounds of four major Chinese carps is established to analyze the effects of the different hydrological regimes changes on the fish habitats. The relationship between the fish habitat suitability index and the hydrological regimes are established. The habitat suitability conditions of four major Chinese carps before and after the cascade hydropower stations construction are comprehensively evaluated. The multi-objective optimization model of ecological operation is established combining the objectives about fish habitat suitability index and other socio-economic indexes of the cascade hydropower stations in the Yangtze River. The scientific and reasonable schemes of ecological operation are proposed for the Yangtze River. The study aims to provide theoretical basis and technical support for fish protection and sustainable use of water resources of the Yangtze River.

水电梯级开发改变了天然河流水流情势，进而改变了河流的泥沙、水温、水质和河道地貌条件，导致鱼类生境突变并产生累积效应。如何减轻水电梯级开发对河流鱼类生境带来的不利影响至关重要。本研究从保护长江中游四大家鱼产卵场生境条件出发，通过对四大家鱼产卵场水文、水动力、水质以及河道地貌等生境因子分析，提出影响鱼类产卵繁殖的关键生境因子；综合运用生态水文学和生态水力学方法，定量评估水电梯级开发对长江中游四大家鱼产卵场生态水文情势改变及其生境累积影响程度；构建四大家鱼产卵场二维物理生境模拟模型，确定鱼类生境适宜性指数和水流情势之间的耦合关系，对梯级电站建设前后鱼类生境适宜性状况进行定量评估；耦合鱼类生境适宜性指数生态目标和其它社会经济目标，构建梯级电站多目标生态调度优化模型和调度方案效果评价模型，提出合理可行的梯级电站生态调度运行方案。研究将为长江鱼类生态保护以及水资源可持续利用提供理论依据和技术支持。

水电梯级开发改变了天然河流水流情势，进而改变了河流的泥沙、水温、水质和河道地貌条件，导致鱼类生境突变并产生累积效应。如何减轻水电梯级开发对河流鱼类生境带来的不利影响至关重要。本项目提出了梯级水电开发累积生态效应框架体系，基于IHA-RVA法，定量评估了长江水电梯级开发对河流生态水文情势改变程度以及重要鱼类产卵繁殖影响程度。采用EFCS法计算长江干流河道内环境流量组成参数，同时考虑河流关键生物所需水流条件，通过HEC-RPT软件可视化并生成推荐的环境流量过程。通过Mike模型构建了长江中下游宜昌-枝城段的水动力学模型，通过PHABSIM法对三峡工程蓄水前后的四大家鱼产卵场进行物理生境模拟，选取7个生境因子作为评价指标，基于模糊综合评价理论方法，建立河流鱼类生境适宜性评价模型，综合评价了三峡梯级水库蓄水前后长江中游四大家鱼产卵场生境适宜性。考虑长江生态流量，构建了长江梯级水库多目标生态调度优化模型，提出了梯级水库生态调度方案。研究为长江河流生态保护与生态修复提供了理论参考和技术支持。.通过4年的研究，在国内外学术刊物发表学术论文17篇，其中SCI2篇，EI2篇，CSSCI1篇；出版专著2部；发明专利4项；获省部级奖励2项；培养硕士研究生4名；参加国内会议6次。总体上来看，较好完成了项目计划书中预期成果目标。研究成果中所提出的筑坝河流生态水文效应综合评估模型以及大坝生态调度模型，对于开展大型河流生态修复工作具有较强理论指导，在一定程度上对于减缓水电梯级工程开发对河流生态系统不利影响具有重大作用。相关研究成果已经应用到郑州市河湖生态修复以及水利工程联合生态调度方面，此外部分研究成果已经应用到黄河流域生态治理与生态修复工作。另外，生态流量计算模型已经应用到洞庭湖流域生态流量和生态水位计算中，对于洞庭湖流域生态修复起到了重要作用。该成果内容丰富，对于我国河流生态修复工作具有较强指导作用，社会效益、经济效益和生态效益显著，推广应用前景广阔。