Research On The Effectiveness Of LID Rainwater System Based On MUSIC

In recent years,impervious pavement has grown and spread significantly with rapid urbanization.The increase in impervious pavement results in more surface runoff.This increased runoff from urban areas would transport large amounts of anthropogenic pollutants to receiving waters and cause a large-scale and non-point source pollution,which are a threat to the water ecology,water safety and water environment.To reduce the effect of runoff on hydrologic system,LID?Low Impact Development approach?was introduced,its controls and natural systems consisting of plants,soil and microorganism that can detain and treat stormwater runoff.However,the effectiveness of LID was not studied widely.Currently,bioretention and infiltration systems are the widely used LIDs.To assess the effectiveness of different LIDs,the performance of bioretention and infiltration systems on the pollution load and discharge was studied in Tianjin Airport Economic Zone.In this study,LIDs' effects on the variability of runoff flow and pollutants under the scenarios of different rainfall temporal distributions were investigated and compared with different rainfall temporal distributions which are?5a₃h₈0%,5a₃h₅0%,5a₃h₂0%?.The first important finding was that with the decrease of temporal distribution probability level,the time distribution of rainfall is more concentrated in the initial state of rainfall and the rainfall peaks were delayed.The second major finding was that under different scenarios of rainfall temporal distributions with the same LID controls,the reduction of flow and pollutants increased with the increasing of rainfall temporal distributions and the occurrences of the peak flow and pollutants were delayed.Because the rainfall with low probability level?more extreme?has larger rainfall intensity,so rainfall will be changed into runoff with less infiltration into the ground so that the pollution and discharge of rainfall runoff were affected.Finally,it was found that the infiltration system is more effective in controlling runoff and preventing water pollution than bioretention system.