基于WEAP模型的西苕溪流域水质安全保障方案

A WEAP-based model for the management of water quality and safety in Xitiaoxi watershed

针对西苕溪流域水质安全问题,基于WEAP建模平台,构建了西苕溪流域水资源评估与规划模型。在模型验证基础上,分析了西苕溪流域2001～2020年河道水功能目标满足度及水供需关系,识别了流域水资源利用存在的问题,并探讨了水源地和中下游区水质安全保障措施及其改善水质的效用,在此基础上提出了西苕溪流域水质安全保障方案。研究表明:TN是影响水源地供水安全的限制性因素,TN、TP是影响河道水功能的重要指标。通过综合实施废水处理厂、节水型设备、退耕还林等水资源管理措施能起到较好地削减TN产出的效果,水源地河道TN浓度降低,基本上能保证全年实现河道Ⅲ类水功能目标,中下游河道TP、TN浓度亦能达到Ⅲ类水功能要求。

The Water Evaluation and Planning （WEAP） model is applied to the Xitiaoxi watershed for an integrated water resources management study.The calibrated WEAP model is used to study the issues concerning the water quality and safety in the watershed for the period 2001-2020.The study includes the ecological function of river systems,quantification of future water demand,as well as sustainable water management practices.Problems associated with the current practices of water management are identified.The study finds that the water quality parameter total nitrogen （TN） is a restrictive factor that affects the safety of water supply in the riverhead protection zone.While,TN and total phosphorus （TP） are the factors that regulate the water function in the middle to lower reach of Xitiaoxi River.We propose that a good and effective integrated water management practice over a watershed should include wastewater treatment plants,water saving devices,as well as implementation plans for conversion of farmland to forests to reduce the concentrations of TN and TP in the river system.Such a reduction in TN and TP concentrations could ensure the water quality and function in the entire river system meeting the Ⅲ level standard throughout a year.