太湖流域设计暴雨时空分布对太湖洪水位影响分析

太湖是太湖流域最大的调蓄水体,合理地推求太湖流域设计暴雨,对于太湖设计洪水位确定非常重要.针对近年来太湖流域变化环境造成的暴雨特性及产汇流机制的变异,采用水文水动力学模型模拟分析了现状条件下太湖流域设计暴雨控制时段及时空分布对太湖洪水位影响.结果表明,以30、60、90日为控制时段的设计雨量与太湖最高洪水位关联密切,控制时段低于30日的暴雨时程分配对太湖最高洪水位基本没有影响.当设计暴雨中心位于太湖上游区域时,模拟的太湖洪水位具有明显升高的趋势,表明太湖洪水位对上游暴雨更为敏感.分析了1999、2016、2020年暴雨为典型的设计暴雨场景,结果表明,暴雨时程分配对太湖洪水位影响显著,主雨峰位于暴雨后期的设计暴雨可以造成更高的太湖洪水位.从太湖防洪安全考虑,采用30、60、90日为控制时段,暴雨中心位于上游,且雨峰位于暴雨过程后期的设计暴雨推求太湖洪水位是合适的.建议将2016、2020年暴雨过程列入太湖设计暴雨计算的备选典型,并作进一步分析论证.

Influence of spatio-temporal distribution of design storm on Lake Taihu flood level

Lake Taihu is the largest area for water storage in the Taihu Basin. How to reasonably derive the design storm is important for determining the flood level of Lake Taihu. Aiming at the variation of storm characteristics and mechanism of runoff yield under changing environments in recent years, the influence of spatio-temporal distribution of the designed rainstorm on the flood level of Lake Taihu under current conditions was simulated and analyzed using a hydrological and hydrodynamic model. The results show that the design storm with 30, 60, and 90-day rainfall durations has more relevance to the highest flood level of Lake Taihu. The design storms with a control duration of less than 30 days have little effect on the the highest level of Lake Taihu. When the designed rainstorm center is located in the upstream region of Lake Taihu, the flood level of Lake Taihu has a significant upward trend,indicating that the flood level of Lake Taihu is more sensitive to the rainstorm of which center is located in the upper basin. The rain that occurred in 1999, 2016, and 2020 were analyzed as typical design rainstorm schemes. The results show that the rainfall process has a significant impact on the flood level of Lake Taihu. Moreover,the results indicate that the majority rain peak,which occurs at the later stage of the rainfall,may cause a higher flood level of Lake Taihu. Considering the security of flood control,it is appropriate to inquire into the flood level of Lake Taihu using the design storm with control periods are 30, 60, and 90 days,assuming that the rainstorm center is located in the upper basin,and the rain peak occurs at the later stage of the rainstorm. It is suggested to involve the rain process in 2016 and 2020 as an alternative typical calculation of design storm of Taihu Basin,and to make further analysis and demonstration.