Method for determining scouring efficiency of water-impermeable surface runoff pollutants on basis of isochrone method

The invention discloses a method for determining scouring efficiency of water-impermeable surface runoff pollutants on basis of an isochrone method and belongs to the cross field of municipal engineering and environment monitoring. A study area is generalized on the basis of monitoring of the surface runoff pollutants, and runoff speed determination, isochrone division and isochrones area determination are performed with the unit time as the dividing point; next, a water outlet flow hydrograph is drown according to isochrones, the pollutant load capacity Mt in the time period is obtained after the difference between the surface runoff pollutant concentration Ct monitored in each time period and the natural rainfall concentration C0 is multiplied by the corresponding flow Qt; then, the total load capacity sigma M is obtained by accumulating runoff pollutant loads in all time periods, and the delta value is obtained by comparing the sigma M with the pollutant load capacity M of surface swept matter before rainf