甘肃省境内典型小流域暴雨特性及洪水过程模拟研究

Simulation Study on Rainstorm Characteristics and Flood Process in Typical Watersheds of Gansu Province

选取甘肃省境内11个典型小流域的水文站实测资料,在分析资料可靠性、一致性、代表性及暴雨洪水特性的基础上,综合利用水文学、数理统计学等理论和方法,建立了小流域最大暴雨量-暴雨历时关系模型、最大洪峰流量-流域特征关系模型。结果表明:各时段最大暴雨量较大值主要分布在泾河流域和嘉陵江流域东南部,较小值主要分布在渭河流域、洮河流域、嘉陵江流域的北峪河;绘制了各代表站最大暴雨量-暴雨历时关系曲线,嘉陵江流域以90min为转折点,其他流域均以180min为转折点,小于转折点时,暴雨量随暴雨历时增长而急剧增加,大于转折点后,变化趋于平缓稳定。重点选取危害较大、难以防范的330场次短历时暴雨洪水,建立各小流域暴雨洪水概化模型,短历时洪水发生时间很短,洪水起涨时间约2~5h,洪峰出现时间约5~7h。研究典型小流域水文要素变化规律,分析局地短历时暴雨洪水特性,并模拟其变化过程,对区域抗旱防汛减灾、水资源管理、小流域治理及生态环境保护具有重要意义。

This paper collected the observed data from the 11 stations in the typical watersheds of Ganshu Province to establish the storm rainfall and storm duration relationship model and the maximum flood peak flow and basin characteristics relationship model for watersheds, by analyzing the reliability, consistency, representativeness and characteristics of rainstorm and flood based on the theories and methods such as hydrology and mathematical statistics. The results show that the larger values of the maximum rainstorms in the various periods are mainly distributed in the Jinghe River Basin and the southeast of the Jialingjiang River Basin,and smaller values are mainly distributed in the Weihe River Basin, Taohe River Basin and Beiyu River in the Jialingjiang River Basin. The following results were obtained from the relationship curves between the maximum storm rainfall and rainstorm duration at the various representative stations. Firstly, the rainstorm intensity has the turning point at 90 min in the Jialingjiang River Basin and at 180 min in the other basins. Secondly, the rainstorm increases sharply with the rainstorm duration lengthing when the rainstorm intensity is less than the turning point. This trend becomes gentle and steady when the rainstorm intensity is greater than the turning point. The generalized models of rainstorm flood were estabished for the various watersheds by analyzing 330 short duration rainstorm floods which are harmful and difficult to prevent. The short duration floods occur in a short time. The rising time of floods is about 2-5 h, and flood peak appear during 5-7 h. It is of great significance for local drought relief, flood control and disaster reduction, water resources management, small watershed management and ecological environment protection to study the change rule of hydrological elements in typical small watershed, analyze the characteristics of local short-duration rainstorm and flood, and simulate its change process.