两江汇流半岛山地城市面源污染模型分析

Analysis on non-point source pollution model of mountainous city in Two Rivers Confluence Peninsula

为模拟研究典型山地老城区重庆市两江汇流半岛的面源污染情况,以管网资料、地形地理资料、气象资料及土地利用资料等作为基础数据,参考国内外相关研究的模型参数设置,构建了两江汇流半岛的降雨面源污染的SWMM模型。对28291个子汇水区、28530条排水管道、28686个排水节点及27种常见污染物进行了模拟。并选取了历史降雨资料中典型暴雨,对典型子汇水区(S1—S6)、典型管段(L1—L6)及典型污染物(BOD、COD、TP、TN)进行了分析。结果表明,在降雨量最大时,整场暴雨的总径流及总出口流量也达到最大,分别为45095.86 m^(3)/s和1374.45 m^(3)/s,各子汇水区及管段的峰值则相对较晚出现。典型污染物BOD、COD、TP、TN的总负荷分别约为1480260、6487821、205608、1935493 kg。各子汇水区及各管段的污染物浓度变化趋势总体一致,峰值均在降雨量最大的18:00出现。为两江汇流半岛的产汇流情况及各典型污染物浓度及负荷分析提供了参考,大大提升了城市环境管理效率及准确度。

To simulate and study the non-point source pollution of the two rivers confluence peninsula in Chongqing,a typical mountainous old urban area,this paper uses the pipeline network data,topographic and geographic data,meteorological data and land use data as the basic data,and refers to the model parameter settings of related research at home and abroad to construct a SWMM model of rainfall non-point source pollution in the two-river confluence peninsula.28291 subcatchments,28530 drainage pipes,28686 drainage nodes and 27 common pollutants were simulated.The typical rainstorms in historical rainfall data were selected to analyze typical subcatchment areas(S1—S6),typical pipe sections(L1—L6)and typical pollutants(BOD,COD,TP,TN).The results show that when the rainfall is the highest,the total runoff and total outlet flow of the entire rainstorm also reach the maximum,which are respectively 45095.86 m^(3)/s and 1374.45 m^(3)/s.However,the peaks of the subcatchments and pipe sections appeared relatively late.The total loads of typical pollutants BOD,COD,TP,and TN are about 1480260 kg,6487821 kg,205608 kg,1935493 kg,respectively.The change trend of the pollutant concentration in each subcatchment and each pipe section is generally consistent,and the peak value appears at 18:00 when the rainfall is the highest.This paper provides a reference for the production and confluence of the two rivers and the confluence of the peninsula and the analysis of typical pollutant concentrations and loads,which greatly improves the efficiency and accuracy of urban environmental management.