基于模型模拟的城市非点源污染控制措施设计

L-THIA-based Management Design for Controlling Urban Non-point Source Pollution

目前针对城市小流域进行非点源污染控制措施去污效果的模拟研究处于起步阶段.利用L-THIA模型模拟武汉市汉阳地区三角湖流域2个小汇水单元(Sj1、Sj2)不同土地利用类型上的非点源污染物累积量,模拟得出1次典型降雨前Sj1和Sj2中污染物总量分别为1.82×104kg、1.38×105kg.基于'源-汇'和格局与过程相互作用理论,针对降雨前2 h内产生的径流,从源、污染物迁移过程和汇3个阶段采取绿色屋顶、草地、多孔路面、渗透渠、植被过滤带和湿塘等多种BMPs及其组合,进行去污效果模拟.结果显示经系列化BMPs处理后进入三角湖的污染物量占Sj1、Sj2总污染物量的14.65%和6.57%,控制措施效果比较明显.在流域或区域尺度上,利用L-THIA模型可以在工程建设之前进行效果预测模拟,以减少不必要的风险.

L-THIA Model was used to simulate the amounts of NPS pollutants in 2 catchments of Sanjiao watemhed （Sj1, Sj2 ） in Hanyang district, and the total simulated amount of NPS loads in Sjl and Sj2 were 1.82× 10^4 kg, 1.38 ×10^5 kg, respectively. Based on the theory of ＂resource-sink＂ and interaction of pattern with process, a series of BMPs, including green roof, grassland, porous pavement, infiltration trench, vegetative filter strip and wet pond, were optimized, and effects of BMPs were simulated along the surface runoff pathway. The results show that total pollutants outputs entering Sj1 and Sj2 account for 14.65% and 6.57%, respectively. Combining L-THIA model and BMPs in series is a proper measure for non-point source pollution control and urban development planning at watershed or region scale.