疏勒河流域生态承载力-水资源耦合机制及优化调控模拟研究

Water resources play a significant role for maintaining the ecosystem balance and the sustainability of the biocapacity in a basin, which is especially prominent in the Inland River Basins of the Arid Regions. The theoretical research of large-scale eco-hydrological process and its coupling mechanism and the regulation of ecological water resources is insufficient in this area, while those research is urgently demanded for our country to construct the ecological security in the Arid Regions. Therefore, this project, based on the typical study area of Shule River Basin, introduces the biocapacity as key ecological indicator, and uses RS/GIS technology and various numerical methods to set up the spatial and temporal coupling models between biocapacity and water resources on the scale of basin and further discusses the coupling mechanism between the two on the basis of analyzing the spatial-temporal pattern and evolution regulation of biocapacity, and the water resources in the Shule River Basin in the past 20 years. Based on above, this project intents to carry out the spatial optimization simulation of biocapacity under multi-target scenarios and restraint condition of water resources for identifying the ecological sustainable development target in basin to calculate the threshold of ecological water requirement based on grid unit. Eventually, this project aims at putting forward the allocation schemes and regulatory policies referring to the ecological water resources in this basin. All the above are for the sake of providing scientific basis to ecological environment protection and rational utilization of water resources in Shule River Basin. The results will enrich the theories and methods of watershed eco-hydrology, and be of great significance for the sustainable development in the arid area and for the implementation of China's “One Belt and One Road” strategy.

水资源在维持流域生态系统平衡和生态承载力可持续性方面扮演着极其重要的角色，干旱区内陆河流域尤为突出。本项目针对干旱区内陆河流域大尺度生态水文过程耦合机制和生态水资源调控研究的不足，并瞄准我国对干旱区生态安全建设的迫切需求，以疏勒河流域为典型研究区，引入生态承载力这一关键生态指标，利用遥感/GIS技术和多种数值方法，在分析该流域近20年生态承载力和水资源时空格局及其演变规律的基础上，构建流域尺度生态承载力-水资源的时空耦合模型，探讨两者的耦合作用机制。基于此，开展水资源约束条件下多目标情景的生态承载力空间优化模拟，以确定流域生态可持续发展目标，计算基于栅格单元的流域生态需水阈值，最终提出该流域生态水资源的配置方案与调控对策，以期为疏勒河流域生态环境保护和水资源合理利用提供科学依据。研究结果将丰富流域生态水文学的理论和方法，对干旱区可持续发展和“一带一路”战略的实施具有重要的指导意义。

本项目针对干旱区内陆河流域大尺度生态水文过程耦合机制和水资源优化配置与调控理论、方法研究的不足，以疏勒河流域为研究区，在R、GeoDA、InVEST、ArcGIS、MATLAB等软件平台上，利用多种遥感反演、数值模拟和统计分析方法，在收集和处理近20年该流域多源遥感、野外观测、室内外样品测试数据的基础上，全面系统地开展了该流域生态承载力-水资源耦合机制研究及优化调控模拟，取得了多项重要结果和关键数据：1）近20年流域生态承载力、植被NPP、EVI指数等生态指标均呈增加趋势；土壤含水量、生态需水量、天然植被耗水量等水文参数均呈增长趋势，而陆表水储量则呈减少趋势；且各项指标空间异质性显著；2）流域“NPP与土壤含水量”、“EVI指数与地表水储量变化”、“生态承载力与生态需水量”等3组关键生态水文参数均呈显著的时空耦合关系，并存在时滞效应；3）首次构建了流域“生态承载力-生态需水-降水”、“生态承载力-陆表水储量-降水”的多元回归耦合模型，指出水资源量对于生态承载力具有较高的解释度；4）首次构建了流域下游“地下水-土壤-植被”结构方程模型，指出地下水埋深变化通过影响土壤理化性质进而影响植被的生长与分布，判定出该区植被生长的最适地下水位埋深范围为2-4m；5）首次提出了基于生态承载力优化目标的流域生态需水量阈值计算方法，并获得三种优化情景下基于栅格的流域生态需水量阈值（分别为16.86×108m3、17.30×108m3、17.97×108m3）及其空间配置格局；6）基于2020—2050年RCP2.6、4.5和8.5三种气候变化情景的流域水资源预测，提出了不同情景下基于农业种植结构调整的农业水资源优化配置方案。最后，基于研究结果提出了流域未来生态需水量和农业水资源的调控对策。本项目研究成果不仅深入揭示了疏勒河流域宏观生态水文过程的耦合机制，提出的相关理论和研究方法弥补了国内外研究不足，具有重要的科学价值，所获得的大量数据和关键结论也必将成为该流域未来生态环境保护、水资源合理调控的重要科学依据，体现出一定的社会意义。