南昌市朝阳新城径流污染特征研究及SWMM模型构建

Study on Characteristics and Construction of SWMM Model of Runoff Pollution in Chaoyang New Town of Nanchang City

以南昌市朝阳新城作为研究区域,选取了3类城市功能区(物流区、居住区、公建区)进行研究,根据降雨实测数据,以悬浮物(SS)、化学需氧量(COD)、总磷(TP)作为主要水质指标,研究不同城市功能区径流污染物随降雨强度、降雨历时的变化规律,分析地表径流中各项水质指标变化原因;并构建SWMM径流污染模型,通过径流污染水质的监测数据,结合降雨情况,不断优化调整率定得到SWMM模型的相关参数。研究结果表明,朝阳新城不同功能区地表径流中同一污染物质量浓度截然不同,在整个降雨历时内,SS污染初期冲刷效应明显,而COD和TP污染随降雨强度的增减变化明显,均呈现出滞后性的特点;物流区SS污染较其他功能区更严重,居住区COD污染最严重,公建区TP污染最严重;各项水质指标模型模拟值与实测值吻合度高,水质参数率定结果可靠。该研究结果为径流污染控制提供了参数依据。

Taking the Chaoyang new town area in Nanchang City as an example,three types of urban functional areas(logistics area,residential area and public construction area)were studied.According to the measured data of rainfall,suspended solids(SS),chemical oxygen demand(COD)and total phosphorus(TP)were the main water quality indicators to study the variation laws of runoff pollutants with rainfall intensity and rainfall duration in different urban functional areas.The reasons for the changes of the above water quality indicators in surface runoff were analyzed;The storm water management model(SWMM)runoff pollution model was constructed.Through the monitoring data of runoff pollution water quality,combined with the rainfall situation,the relevant parameters of the water quality model were obtained by continuous optimization and adjustment.The results show that the concentration of the same pollutant in the surface runoff of different functional areas is quite different.During the whole rainfall duration,the scouring effect of SS pollution is obvious at the initial stage,while both COD and TP pollution change significantly with the increase or decrease of rainfall intensity and show the characteristics of hysteresis.SS pollution in logistics area is more serious than that in other functional areas.COD pollution in residential area is the most serious.TP pollution in public construction area is the most serious.The simulation value of each water quality index model is in good agreement with the actual monitoring value.The calibration result of water quality parameters is reliable.The study provides a parameter basis for the study of runoff pollution control.