基于SWMM的铁心桥实验基地内涝防治效果模拟

Simulation of waterlogging control effect in Tiexinqiao experimental base based on SWMM

基于南京水科院铁心桥实验基地的地形、下垫面条件等数据构建了SWMM,模拟了实验基地象目湖观景平台和水上餐厅两个监测点在不同降雨重现期、低影响开发措施、溢流孔设置和水泵强排条件下受淹情况。结果表明,初始水位较低(25.1 m)时,象目湖遭遇500年一遇的降雨事件时水位并未抬升至水上餐厅。初始水位较高(25.6 m)时,200年一遇和500年一遇的降雨事件中水上餐厅受淹持续时间分别为7 h和11 h。采用集水池、雨水花园和生物滞留池3种LID措施对象目湖水位峰值影响模拟结果显示,在5年或10年一遇的降雨事件中雨水花园和集水池可以分别降低象目湖峰值水位0.06 m和0.02 m,生物滞留池没有削减峰值水位。在降雨量为218.5 mm的20160707次降雨事件中LID措施削减象目湖水位效果不明显。水泵抽排流量越大,象目湖水位越早回落到观景平台以下。LID在应对造成城市内涝的低频次、短历时强降雨方面作用有限,铁心桥实验基地象目湖内涝防治应以加强水文气象预测和水位管理、加大溢流孔尺寸和采用水泵强排等措施为主。

Based on the data of terrain and underlying surface of Tiexinqiao experimental base of Nanjing Hydraulic Research Institute, SWMM was constructed. The flooded situation of two monitoring points of Xiangmu Lake observation platform and waterside restaurant in the experimental base were simulated under different rainfall return period, LID measures, overflow hole setting and strong drainage of water pump. The results show that when the initial water level is low(25.1 m), the water level of Xiangmu Lake does not rise to the waterside restaurant when encountering a rainfall with 500-year return period. When the initial water level is high(25.6 m), the inundation duration of the waterside restaurant is 7 h and 11 h respectively for the rainfall with 200-year return period and 500-year return period. The influence of three kinds of LID measures of collecting pool, rainwater garden and bioretention pond on the peak water level of Xiangmu Lake was simulated. The simulation results show that the peak water level can be reduced by 0.06 m and 0.02 m respectively in the case of 5-year or 10-year rainfall events when using collecting pool and rainwater garden, and the peak water level cannot be reduced by the bioretention pond. In 20160707 rainfall event with rainfall of 218.5 mm, the effect of LID measures on water level reduction of Xiangmu Lake is not obvious. The larger the water pump discharge, the earlier the water level of Xiangmu Lake falls below the observation platform. LID measures play a limited role in dealing with low frequency and short duration heavy rainfall which causes urban waterlogging. The main measures to control the waterlogging in Xiangmu Lake of Tiexinqiao experimental base are to strengthen the hydrometeorological forecast and water level management, increase the size of overflow hole and adopt the strong drainage of water pump.