西咸新区海绵城市建设对沣河洪水特性影响模拟研究

为评估海绵化改造对城市内河洪水特性的影响，基于模型GAST（GPU accelerated surface water flow and transport model），定量研究了理想流域和沣河流域西咸新区沣西新城段海绵城市建设前后在3种入流条件（2.75、7.69、17.06 m³/s）和3种降雨重现期（2、10、50 a）组合工况条件下的洪水流量过程。结果表明：设计降雨重现期为2、10、50 a时，理想流域的峰值流量削减率在6.64%~67.34%之间，实际流域的峰值流量削减率在2.66%~43.57%之间，两者差别不大。海绵化改造在一定程度上削减了内河的峰值流量，峰值削减率与上游来流量呈反比，与区间汇流量成正比。但峰现时间有延迟有提前，无明显规律。

Effects of sponge city construction on flood characteristics of Fenghe River in Xixian New Area

To evaluate the impact of sponge transformation on flood characteristics of urban inland rivers, based on GPU accelerated surface water flow and transport model (GAST), the change of flood characteristics of Xixian Fengxi New Area Section, Fenghe River Basin and the ideal basin before and after sponge city construction is quantitatively studied under the combination of three inflow conditions (2.75 m³/s, 7.69 m³/s, 17.06 m³/s) and three rainfall return periods (2 a, 10 a, 50 a). The results indicate that when the rainfall return period is 2 a, 10 a and 50 a the peak flow reduction rate of the ideal basin is in the range of 6.64%-67.34%, and that of the actual basin is in the range of 2.66%-43.57%, which is not significantly differentiated. In other words, sponge transformation reduces the peak flow of inland rivers to some extent, the rate of which is in inverse proportion to the upstream flow but direct proportion to the interval influx. It will either delay or bring forward the occurrence of peak flow, showing an irregular pattern.