Research On Surface Contaminants Washoff Rule And The First Flush Effect With Artificial Rainfall Simulation

China has vast territory and abundant resources, with lots of rivers in it, but the distribution of water resoure in time and space is unbalance,and water pollution seriously hamperd the development of the national economy. At present the country are vigorously promoting the water protection and restoration,but after controled the point-pollution which is caused by life and industry, the quality of urban water environment still can't be improved effectively,this phenomenon makes people paying more attention from the original non-point source pollution, and gradually transferred to area-source pollution, and storm runoff pollution is an important source of non-point source pollution.Based on the theoretical research and typical type of practical city surface, three materials (glass,cement and road brick) are selected,researching for pollutants washoff rules, first flushing effect, and the early rain criterion under the different condition of initial simulation pollutants quantity, rainfall intensity and gradient. The main research results are as follows:(1) Under different condition of surface type, initial simulation pollutants quantity, rainfall intensity and gradient, simulation pollutants have similar wasoff rules:initial runoff has higher concentrations of simulate pollutants, along with the growth of cumulative rainfall, s concentration of simulate pollutants decreased gradually until stability. Washoff effect of solubilize simulate pollutants is better, the initial concentration is higher and concentration changes significantly, total washoff amount is bigger. Washoff effect of insolubilize simulate pollutants is poorer, the concentration of initial concentration lower, concentration changes, and total washoff amount is smaller. For glass surface, solubilize and the insolubilize simulate pollutants coefficient k could adopt 0.408 and 0.118, respectively; for cement surface, solubilize and the insolubilize simulate pollutants coefficient k could adopt 0.082 and 0.057, respectively; for road brick surface, solubilize and the insolubilize simulate pollutants coefficient k could adopt 0.272 and 0.266,respectively.(2) Under different condition of surface type, initial simulation pollutants quantity, rainfall intensity and gradient, simulation pollutants have strong first flushing effect. First flushing effect coefficient kn continue to drop as cumulative runoff increased. For glass surface, about 30% of runoff will control about 90% solubilize pollutant and 60% insolubilize pollutants,respectively;for cement surface, about 30% of runoff will control about 99% solubilize pollutant and 44% insolubilize pollutants,respectively; for road brick surface, about 30% of runoff will control about 90% solubilize pollutant and 70% insolubilize pollutants,respectively.(3) According to the test results and chaohu dustfall monitoring results of atmosphere, the amount of rainfall runoff erosion in chaohu CODCr, SS, TN, TP, ammonia nitrogen can be estimated as 8.9361t,18.8340t,2.2209t,0.0538t,1.4376t, respectively; atmospheric dust in old urban area of chaohu produced CODCr, SS, TN, TP, ammonia nitrogen as 38.2777t,78.0152t,9.0032t,0.2091t,4.2422t, respectively; CODCr, SS, TN, TP, ammonia nitrogen runoff erosion rate as 24.14%,23.34%, 33.89% 24.67%,25.73% respectively. Suggest of transformed nearby river into artificial wetland or artificial ponds to treat the rain pollution.