基于水-经济社会-生态环境协同演变的生态流量阈值适宜性研究

Suitability of ecological flow thresholds based on the simulation of coordinated development of water-economic society-ecological environment

针对天门河-汉北河流域生活-生产-生态“三生”用水矛盾突出、水生态退化及经济社会发展受限等问题,基于水系统理论与系统动力学方法,构建“水-经济社会-生态环境”耦合模型,从系统层面研究河道内生态流量阈值的适宜性。应用情景模拟法,考虑高效节水、再生水利用率提高等调控措施及未来天然来水的不确定性,设置9种情景模拟2022—2035年研究区高、中、低3种生态流量阈值下的水资源供需及经济社会发展态势。结果表明:高效节水和再生水利用率提高均有利于缓解因生态流量阈值增大而引起的区域水资源用户间的冲突问题;从“水-经济社会-生态环境”协调发展的角度分析,建议研究区丰水年(P=25%)生态流量阈值设置为年径流量的30%~50%,平水年(P=50%)和枯水年(P=75%)生态流量阈值设置为年径流量的10%~30%;增大生态流量阈值的同时应采取提高水资源利用效率的调控措施。研究结果从“水-经济社会-生态环境”耦合系统的协同演化机制出发分析河流生态流量阈值的适宜性,为复杂水资源系统的优化运行与科学管理提供了理论基础。

The Tianmen-Hanbei River Basin is afflicted by aggravating problems,such as water use contradiction between life,production and ecology,degradation of water ecology and restriction of socio-economic development.In order to solve these problems,this study constructed a coupled water-economic society-ecological environment model based on water system theory and system dynamics method,so as to examine the suitability of in-stream ecological flow thresholds at the system level.With the application of the scenario simulation method,nine scenarios were set up to simulate the water resources supply and demand,along with economic and social development in the study area under high,medium and low ecological flow thresholds from 2022 to 2035,based on the uncertainty of future natural water supply and control measures such as efficient water conservation and increased utilization of reclaimed water.The results showed that both efficient water conservation and increased utilization of reclaimed water are beneficial for alleviating conflicts between regional water users caused by the increase of ecological flow thresholds.From the perspective of coordinated development of water-economic society-ecological environment,it is recommended that the ecological flow thresholds for wet years(P=25%)in the study area should be set at 30%-50%of annual runoff,while 10%-30%for normal years(P=50%)and dry years(P=75%).In addition,increasing ecological flow thresholds should be accompanied by regulatory measures to improve water resources utilization.This study investigates the suitability of ecological flow thresholds for rivers based on the water-economic society-ecological environment co-evolutionary mechanism,which provides a theoretical basis for the optimization and scientific management of complex water resources systems.