北方平原城市LID设施控制雨洪效果研究OA

The construction of Low Impact Development(LID)facilities has a significant impact on alleviating urban waterlogging disasters.To study the effect of LID facility construction on rain and flood control in the northern plain area,this paper constructs a Storm Water Management Model(SWMM)based on the district as the base of the central urban area of Hengshui city,analyzes the current pipe network flow capacity,and simulates and compares the rain and flood control effects before and after the construction of LID facilities in the central urban area from the aspects of annual total runoff control rate and flood risk.The simulation results show that the drainage capacity of the central part of each area in the central urban area is relatively lower than that of the surrounding areas.More than 50%of the pipe network has a good drainage capacity,but about 30%of the pipe network still needs to be renovated.After the con-struction of LID facilities,the annual total runoff control rate in the central urban area has significantly increased to 76%,an increase of 14%compared with the development and construction before.The annual total runoff control rate of each key district has reached more than 75%.By comparing the flood risk in the built-up area of the central urban area under a 30-year return period 24-hour rainfall(cumulative rainfall of 195.7 mm)before and after the construction of LID facilities,the flood risk area has decreased by 4.46 km2 after the construction,and all 8 severe flood waterlog-ging points that appeared before have been eliminated.The flood prevention standard area is about 71.59 km2,account-ing for 93.3%of the built-up area,and the flood prevention standard area has reached the standard.The construction of LID facilities in the central urban area can effectively cope with a 30-year return period of heavy rain.