针对水温-水量情势失调的气候变化下澜沧江水库生态调度方法研究

Climate change as well as reservoir operation can change the regime of flow temperature, and consequently change the requirement of environmental flows (e-flows). The present ecofriendly reservoir operation methods highlight the magnitude of flow magnitude but simplify flow temperature, which will lead to the imbalance between magnitude and temperature regimes. This research focuses on the imbalance, and follows the research thread of “imbalance characteristics analysis—e-flow determination—operating rule development”. Firstly, we analyze the degree of the imbalance and the spatial and temple variations. Then, the regime of flow temperature is incorporated into the process of e-flow assessment to establish a new e-flow method considering both magnitude and temperature, which is used to address the problem in previous e-flow methods under climate change that assume the e-flows are not influenced by flow temperature changes. Finally, the relationships among the height of the stoplog gate, the reservoir water level and the temperature of water released are established, and new reservoir operating rules are developed to address the imbalance between flow temperature and magnitude based on the established temperature-magnitude-food web model. This research takes the Nuozhadu reservoir as the research reservoir and the river segment between Nuozhandu and Jinghong reservoirs as the environmental protection area, and highlights the imbalance between temperature and magnitude caused by climate change and reservoir operation. The research is closely related to the aim of the planned major research project, and specifically focuses on “southwest rivers”, “changed environment”, and “adaptive runoff utilization”.

气候变化以及水库建设会影响河流水温情势，改变河流生态需水。现有水库生态调度方法侧重水量而略化水温调控，会造成水温情势和水量情势不协调。本课题针对水温-水量情势失调问题，以“失调特征分析-需水阈值确定-调度规则建立”为思路，分析气候变化以及水库影响下河流水温-水量情势失调程度及时空变化规律；纳入水温情势，建立考虑水温-水量情势协调性的生态需水核算方法，解决气候变化下核算方法假定生态需水不随水温变化的问题；分析叠梁门高度与门顶淹没深度对下泄水温的影响，结合建立的水温-水量-食物网关系模型，构建协调水温和水量情势的水库生态调度规则。本课题以澜沧江糯扎渡水库为重点调度水库，以糯扎渡-景洪河段为重点河流生态保护区域，强调气候变化这一环境变化对生态需水的影响，直接服务于重大计划中“西南河流”“变化环境下”“径流适应性利用”研究目标。

面对我国水电开发及河流生态系统保护的迫切需求，针对现有生态流量调度方法难以解决气候变化下水温情势和水量情势变化的问题，本研究采用水温和水力模拟、生态模型、气候变化模型等方法，对气候变化下生态流量调度方法开展了系列研究。通过文献调研，总结出不同水温参数在河流中的生态作用，定性分析这些水温参数与生态系统的关系。依据水温参数不同时期的生态敏感性、受水库影响程度等性质，对参数进行排序，并利用主成分分析、冗余分析等数学方法对水温参数进行筛选。基于筛选出的水温参数指标体系及常用水量情势指标体系，开展了气候变化下河流中水量情势和水温情势相关关系分析。结合生态系统发生突变前对应的流量、水温情势范围，确定维持生态系统健康需要的综合情势阈值范围，针对各个流量时期（洪水期、高脉冲期、枯水期、平水期）分别给出生态需水量。对洪水期、高脉冲期、平水期、枯水期四个流量时期，与不同调度策略下的下泄流量、水温模拟结果相结合，制定不同流量时期叠梁门运行规则。基于所制定的不同流量时期的叠梁门运行和水库调度规则，结合气候变化影响下的径流条件并考虑其不确定性，确定不同库区蓄水位下的水库调度策略，以生态系统保护为生态目标，同时以水库发电效益最大化为经济目标，以水库防洪需求、下泄能力、发电能力等为约束条件，建立水库调度的优化管理模型。基于上述成果，本项目发表8篇SCI论文。