基于水量-水质耦合过程的流域水生态承载力优化方法与例证

An optimization approach for watershed ecological carrying capacity analysis based on coupled water quantity-quality process

水质与水量是影响水生态系统健康的重要因子,开展以生态需水和功能区水质达标为核心的水生态承载力研究对改善流域生态用水不足和水污染具有重要意义.当前流域水生态承载力优化方法将水量和水质作为独立系统处理,忽视了其耦合关系.基于河流水质模型和水资源模型,建立了流域水环境容量与环境流量的函数关系,并作为水生态承载力优化模型的约束条件,构建了以人口与产业规模最大化为目标的水生态承载力的优化模型.最后,对水污染严重且水资源短缺的盘龙江流域进行了实证研究.结果表明:建立的水生态承载力模型能够反映水量与水质的耦合作用,从而提高了流域水生态承载力决策的科学性;盘龙江流域的水生态承载力为20.56万人和119.24亿元GDP,2014年的流域现状值超载了234%;流域水生态承载力与环境流量比例具有显著的补偿关系,呈现倒V型非线性变化过程;当外流域调水的水质高于或等于受水区水质时,受水区的水生态承载力可得到一定程度的提高.

Water quality and water quantity are key factors affecting water ecological system health. It is of great importance to study water ecological carrying capacity which focuses on meeting water ecological requirement and water quality targets to mitigate water pollution and water shortage problems.However,water quantity and water quality have been taken as independent systems in current water ecological carrying capacity optimization models,overlooking the mutual effects between them. Based on water quality model and water resources use model,a function of water quality and quantity is established and used in the optimization model of water ecological carrying capacity aiming to maximum population and economy. Finally,Panlongjiang River watershed which suffers from severe water pollution and water shortage is taken as a case study. Results showed that,（1） the established model has the ability to reflect the coupled process of water quantity and water quality,which will improve the scientific basis for decision making of watershed water ecological carrying capacity;（ 2） the water ecological carrying capacity of Panlongjiang River watershed is a population of 205.6 thousand and a GDP of11.92 billion RMB,and in 2014 the watershed was overloaded by 234%;（ 3） a significant trade-off was found between water ecological carrying capacity and environmental flow percentage,showing in an inverted V shape;（ 4 ）addition of flow from other watershed may increase water carrying capacity if water quality is not worse than the water received region.