Stormwater Managenment Program Simulation Study Of LID Based On SWMM-the Case Of Beijing Changpin A62 Plot

Plot A62 in Beiqijia Town, Changping district, Beijing was chosen to be study area. SWMM model was used to compare the flood change of urbanization in study area. At the same time, it was used to compare the influence on the flood of study area between urbanization with single LID measurement (sunken lawn, permeable pavement, green roof) and urbanization with different LID units. Different rain conditions were set up to select the best flood control program in this study area.The results showed,1) The traditional way of urbanization in the study area reduced the resistance of forming surface runoff with the increase of impervious area, which increased by 2.70 times of the peak flow and the peak time was 14 min in advance.2) The sunken lawn, the permeable pavement and green roofs reduced the flood peak flow and delay the peak time, but the effect is different in different rainfall return period.Sunken lawn reduced peak flow efficiently and delay the peak time. With the increasing of rainfall return period, the effect become better, especially in the condition of small rain intensity.Control effect to peak flow of permeable pavement concentrated between 11.15% and 49.51%, and delay 4 min of the peak flow time.The effect of green roofs to reduce the peak flow concentrated between 8.08% and 16.59%, delayed the appearance time of peak flow, but there was no obvious regularity. The effect of reducing peak flow decreased with the increase of rainfall return period.The effects of sunken lawn and permeable pavement were better than green roofs in this study area..3) LID units were better than single LID except combination 2 under P=1, P=3, which was weaker than the effects of permeable pavement and sunken lawn, and reduce8.93 times of difference between peak flows. Combination 4, sunken lawn+permeable pavement+ green roofs had the best effect, which can reduce 70% peak flow under all the rainfall return period.