Characterization of rainfall runoff pollution transportation in different underlying surface of Dongguan City

Based on runoff water quantity and quality monitoring of representative of different land use in Tongsha Reservoir catchment,pollution output process,pollution situation and first flush effect in Dongguan city were analyzed.According to distribution regulations of runoff pollutant loads,the first flush interception reference criteria had been discussed.And principal component analysis was applied to conclude main factors influencing on runoff pollutant loads.The results eventually showed that the runoff pollution concentration of the reservoir catchment was close to the concentration value of typical sewage,pollutant loads were high,resulting in a serious effect to the water quality of the reservoir.Rainfall runoff output had significant features of time,and the common first flush had occurred.The main factors of pollution loads include maximum rainfall intensity,antecedent dry days and waterproof rate.Using FF40 as the reference value of early period runoff retention,intercepting the early 40% of runoff volume would be more effective and economical than intercepting the whole.