Monitoring And Control Of Rainfall Runoff Pollution Of Small Watershed In Southern City

Regional urban rainfall runoff pollution has received widespread attention in recent years.Due to the multiple and complex types of urban land in high-development urban small watersheds,there is a systematic lack of monitoring programs during the study of runoff pollution characteristics,limited accuracy of limited natural rainfall monitoring,Runoff pollution control technology is not well targeted.In this paper,taking the G River in a typical small city in the south as the research object,by establishing a systematic construction method for runoff pollution monitoring programs,the monitoring layout optimization and identification of key monitoring indicators are realized,the characteristics of runoff pollution are analyzed,and a runoff pollution control plan is proposed;Establish a rainfall runoff pollution analysis and control effectiveness evaluation model for small urban watersheds,determine the pollution load of regional runoff pollution on the G River,and evaluate the effectiveness of related control technologies.Research on the systematic construction method of rainfall runoff pollution monitoring scheme in urban small watersheds and its application in G River.Adopt drawing analysis,site survey and GIS hydrological analysis to optimize monitoring points,determine monitoring indicators by frequency analysis method and single factor pollution index method,analyze functional elements of runoff pollution control measures and determine monitoring analysis content,and improve traditional runoff Pollution monitoring methods are inadequate in the monitoring layout,monitoring indicators are not representative,and monitoring analysis content is not targeted.The results show that the monitoring layout of a systematic runoff pollution monitoring program should cover cumulative monitoring,erosion monitoring and confluence monitoring.The SWAT model can be used to subdivide the land types locally;the monitoring indicators can be identified by the single factor pollutant index method.Priority is given to selecting pollution indicators with a pollution index greater than 1.0.The contents of monitoring analysis shall be for the purpose of formulating control measures for runoff pollution and local identification of model urban parameters,covering the accumulation characteristics and scour characteristics of surface pollutants,focusing on the analysis of surface accumulation laws,pollutant morphological characteristics and initial scour effects.The application of the systematic construction method of runoff pollution monitoring in the G River in the southern high-development cities was carried out,and the points of cumulative monitoring and erosion monitoring were refined to industrial land,high-density residential land,medium-density residential land,transportation land,and commercial land.And public management service land and other areas,the monitoring indicators are determined to be TN,TP and ammonia nitrogen.The results show that the constructed runoff pollution monitoring scheme can simplify the monitoring work,improve the monitoring efficiency,guide a limited number of accumulation and erosion monitoring work,and realize the research on the key characteristics of rainfall runoff pollution in small urban watersheds;the surface TN of high-density residential land in the G river basin The content of TP and ammonia nitrogen is the highest.The surface pollutants are mainly solid particulate pollutants with a particle size of less than 500 ?m,and their pollution load can account for as much as 70% or more.The initial scour effect of pre-peak and bimodal rainfall events is more In order to be significant,the initial rain abandonment in different areas of the G River Basin is 9 mm at the initial stage,which has important reference value for the development of runoff pollution control measures in the G River Basin.Based on the limited-time representative runoff pollution monitoring,the construction method of rainfall runoff pollution SWAT model was studied,the spatial and temporal distribution characteristics of runoff pollution in the G River Basin were analyzed,and a runoff pollution control scheme to control the main pollutants was proposed.The results show that the key to the establishment of the SWAT model of rainfall runoff pollution in small watersheds in high-development cities in the south lies in the second-stage reclassification of land-use data and the establishment of a model urban database.The construction of the SWAT model requires the four categories of DIRTMX,TNCONC,TNALF,and TPCONC.The parameters are localized and corrected through the study of surface pollutant accumulation characteristics;monitoring and simulation results show that the SWAT model can more accurately predict and analyze pollution loads such as runoff,TN,and TP in the G River Basin;for the control of runoff pollutants,management and engineering measures should be taken Carry out control,including road cleaning,adding storage tanks,etc.