Multi-Objective Ecological Operation of Large-Scale Reservoir-Gate System Coupled with Vegetation Priority Irrigation in Arid Regions.

Under the influence of climate change and human activities, riparian ecosystems in arid regions are facing severe challenges such as extensive vegetation death. Meanwhile, conventional reservoir operation and vegetation irrigation have low water use efficiency and unsatisfactory vegetation restoration effect. For improving the efficiency of water resources regulation and protect riparian ecosystems in arid regions, this study proposes a multi-objective reservoir-gate ecological operation model coupled with vegetation priority irrigation. Firstly, based on ecological project layout and riparian vegetation types, ecological irrigation districts and ecological functional zones are divided for precise zoning water regulation, and then the irrigation order of "key protected zones > key restoration zones > ecological sensitive zones" and the water supply priority of irrigation districts are formulated for vegetation priority irrigation. Secondly, a long-term multi-objective reservoir-gate operation model coupled with vegetation priority irrigation is established, and an improved parallel approximate evaluation-based algorithm (RG-PAEM) is proposed for enhancing the search ability and calculation efficiency of optimization model. Finally, ecological operation effects under vegetation priority irrigation are analyzed through a case study of Tarim River basin in northwestern China. Results show that: (1) compared with conventional ecological irrigation, vegetation priority irrigation improves ecological and agricultural water supplies in Tarim River mainstream; (2) under vegetation priority irrigation, annual ecological water supplies of Level I to Level V irrigation districts account for 3%, 15%, 28%, 48%, and 6% of the total, respectively, and monthly ecological water supply reaches the maximum in July; (3) the upper and middle reaches of mainstream are important areas for riparian vegetation protection, the ecological water shortage decreased by 10% and 16% respectively through reservoir-gate ecological operation and vegetation priority irrigation. The study results provide theoretical and technical support for achieving scientific water resources regulation and sustaining desert riparian ecosystems. [ABSTRACT FROM AUTHOR]