面向生态系统多对象保护与修复的水库优化调度

Optimization of reservoir operation for multi-object protection and ecosystem restoration

近20 a来,随着塔里木河(简称“塔河”)流域水资源综合规划与调度的实施,已基本实现“水流到台特玛湖、大西海子水库多年平均下泄3.50×10^(8)m^(3)”的生态输水目标。但是,塔河下游其文阔尔河与老塔里木河之间的两河区域内植被稀少、生态环境脆弱,多年的生态恢复效果并不显著。鉴于此,本文以大西海子水库为调控主体,以大西海子下泄生态水量、河道内生态基流、台特玛湖生态输水、河道外生态供水等为生态保护对象,建立了水库中长期生态优化调度模型,采用粒子群算法进行求解。结果表明:(1)优化调度后大西海子水库多年平均下泄水量为5.23×10^(8)m^(3),满足塔河一期规划3.50×10^(8)m^(3)水量要求,且下游河道常流水时间显著延长;(2)优化调度后多年平均入台特玛湖水量为0.18×10^(8)m^(3),相较于实测数据,增加了20.0%,且入湖过程更加平稳,有利于巩固已初步形成的尾闾湖泊生态系统;(3)优化调度后塔河下游河道生态基流保证率为50.0%,不断流的保证率达64.6%,对受人类活动影响巨大的我国最长内陆河——塔里木河下游河道生态系统具有重要积极影响;(4)优化调度后塔河下游河道外多年平均生态供水量1.67×10^(8)m^(3),为下游两河区域的荒漠河岸植被林生态恢复奠定了水量基础。研究成果对于塔河下游两河区域的荒漠河岸植被林修复与保护、维持河道和尾闾湖泊的生态健康、构建地下生态水银行具有重要的应用价值,也对于构建塔河生态流域具有重要的现实和推广意义。

Over the past 20 years,the implementation of a comprehensive plan for water resources of the Tarim River basin has resulted in ecological water delivery to Taitema Lake and Daxihaizi Reservoir of an average 350 million m^(3).However,two areas between the Wenkuer River and Old Tarim River,in the lower reaches of the Tarim River,have sparse vegetation and fragile ecological environments.Ecological restoration efforts over many years have not had a significant effect.In view of this,the study attempted to establish the medium-and long-term ecological optimization of the reservoir.A model was developed based on the Daxihaizi Reservoir as the main water body for regulation,the ecological water discharged from Daxihaizi,the ecological base flow in the river,the ecological water delivery of Taitema Lake,and the ecological water supply outside the river as ecological protection objects.The scheduling model was solved using particle swarm optimization.(1)Under optimal operation conditions,the Daxihaizi Reservoir had an average annual discharge volume of 523 million m^(3),which meets the 350 million m^(3) water requirement of the first phase of the Tarim River,and the downstream river channel had a significantly longer constant flow time.(2)With optimized discharge,the average volume of water entering Taitema Lake was 18 million m^(3),which is an increase of 20.0%compared with the measured data.The process for water entering the lake was more stable,which is conducive to consolidating the initially formed lake ecosystem.(3)With optimized discharge,the guaranteed rate of ecological base flow in the lower reaches of the Tarim River was 50.0%,and the guaranteed rate of continuous flow reached 64.6%.The improved ecological flows had an important positive effect on the ecosystem of the lower reaches of the Tarim River,which is greatly affected by human activities.(4)After the optimized operation,the average ecological water supply outside the lower reaches of the Tarim River was 167 million m^(3),laying a foundation for ecological restoration of the forests on the banks of the lower two rivers.These results have important application value for the restoration and protection of desert riparian vegetation in the lower reaches of the Tarim River.Such efforts could help to maintain the ecological health of river courses and tail lakes,and develop ecological groundwater banks.