基于多耦合模型的盛桥河流域水环境模拟研究

Simulation of water environment in the Shengqiao River Basin based on multi coupling model

[目的]对流域水环境污染进行解析、评估和预测,为流域水环境综合治理决策提供参考.[方法]以合肥市庐江县盛桥河流域为例,搭建流域水文、水动力与水质多耦合水环境模型,通过陆域-水体全过程模拟,解析污染负荷分布与河道水质响应规律,预测城镇截污纳管、农村污水处理、畜禽水产养殖整治、非点源污染管理措施及其组合情景下水环境治理效果.[结果]模拟可知,盛桥河流域典型丰、平、枯水年非点源NH3-N入河污染负荷分别为88.23,42.81与35.45 t/年,TP入河污染负荷分别为7.53,3.65与3.24 t/年.最不利水文年(枯水年)汛期和非汛期河道水质均有超标现象,NH3-N和TP最大超标倍数分别为1.42和0.90.河道流量与水质有较强的相关性,在低流量区间内,随着流量的增大水质有所好转;当流量大于0.52 m^(3)/s时,TP的质量浓度趋于稳定,NH3-N的质量浓度有所升高.多措施综合治理后,盛桥河水质可达到地表Ⅲ类水标准,流域出口NH3-N的月平均质量浓度低于0.91 mg/L,TP低于0.18 mg/L.[结论]所构建的流域水文、水动力与水质多耦合水环境模型在流域水环境污染解析、评估与预测应用中具有较好的可靠性和普适性.盛桥河流域汛期与非汛期河道水质的主导因素分别是非点源和点源污染,流域水-陆统筹、点-面兼治是解决流域水环境问题的根本原则.

【Objective】By analyzing,evaluating and predicting water environment pollution of watershed,this study attempted to provide a reference for decision-making in comprehensive water environment management in watershed.【Method】Taking the Shengqiao River Basin in Lujiang,Hefei as an example,a multi-coupling water environment model of basin hydrology,hydrodynamics and water quality was established.With whole process simulation of land and water,the distribution of pollution load and response of river water quality were analyzed,and the water quality was predicted with the implementation of municipal sewage collection,rural sewage treatment,livestock and poultry breeding and aquaculture regulation,non-point source pollution management and their combinations.【Result】According to the simulation,the loads of non-point source NH 3-N entering the river in typical wet,normal and dry years were 88.23,42.81 and 35.45 t/a,and those of TP were 7.53,3.65 and 3.24 t/a,respectively.In the most unfavorable hydrological years,the water quality in different seasons exceeded standard,and maximum NH 3-N and TP concentrations were 1.42 and 0.90 times higher than the standards,respectively.The river flow had significant correlation with water quality,and it improved as the flow increased in low flow range.When the flow was greater than 0.52 m^(3)/s,TP concentration tended to be stable,while NH 3-N concentration increased.The implementation of water environment treatment measures promoted water quality to meet the surface water classⅢstandard,and monthly concentrations of NH 3-N and TP of the basin outlet were lower than 0.91 and 0.18 mg/L,respectively.【Conclusion】The multi-coupling hydrology,hydrodynamics and water quality model had excellent reliability and versatility in the application of water pollution analysis,evaluation and prediction in river basin.The dominant factors of Shengqiao River water quality in wet and dry seasons were non-point source and point source,respectively.Water-land co-ordination and point-surface co-management were fundamental principles to solve water environment problems of the river basin.