MODELING HYDROLOGICAL EFFECTS OF LOW IMPACT DEVELOPMENT FOR STORMWATER RUNOFF TREATMENT BASED ON STORM WATER MANAGEMENT MODEL

摘要

Increases in urbanization and conversion of land for urban use have resulted in increased areas of impervious surfaces, leading to greater runoff volume and pollution. In this study, local conditions and low impact development (LID) implementation principles were used to select and arrange appropriate LID measures. Storm water management model was used to simulate and assess the performance of LID measures compared with natural and original scenarios in different designed storm series.After the LID measures were set, the runoff volume of the LID scenario decreased from 22.3% to 55.4% as return periods increased, the average flooding time of the LID scenario decreased by 48-67 min compared with the original scenario, the maximum flooding time decreased by 37-70 min, and the total flooding volume decreased by 40.3-90.6%. Moreover, TSS, TN, TP and COD emissions of the LID scenario were 5471135 kg, 3.2-5.5 kg, 0.5-1.4 kg and 84.0-213.5 kg lower, respectively, relative to the original scenario. R value had little effect on runoff volume and flooding time, but obviously influenced total flooding volume and pollutant emissions. As rainfall duration increased from 0.5 to 4 h, rainfall increased from 21.6 to 40.9 mm, and runoff volume, flooding characteristics and pollutant emissions increased gradually, although the increase amount and rate of four pollutants gradually decreased.Compared with the natural and original scenarios, the LID scenario reduced both the risk of runoff and pollution. The results of this study will enable useful recommendations for modifying present stormwater management systems, both at this and other urban sites, to achieve improved runoff control.