岩溶地区水库工程设计洪水分析

贵州省是中国典型的岩溶地貌分布地区之一,由于地区岩溶、伏流、泉点、洼地分布多,地形地貌复杂,各种地貌单元产汇流条件各不相同。当坝址以上流域伏流暗河区占比较大情况下,计算设计洪水时若按全流域计算,成果往往较天然洪水偏大。文章以贵州省石板滩水库为例,将坝址以上明流区、伏流暗河区分别叠加计算设计洪水,并与全流域设计洪水对比,结果表明:按全流域考虑成果明显偏大,采用叠加组合分析成果与历史洪水调查成果接近。

Analysis of Design Flood for Reservoir Project in Karst Area

Guizhou Province is one of the typical Karst region in China.Due to the wide distribution of karsts,underground streams,springs and depressions in the area,the topography and landforms are complex,and the conditions for the runoff yield and concentration of various landforms are different.When the underground rivers area occupies a relatively high proportion in the river basin upstream of the dam site,the result of the design flood calculated based on the whole basin is usually larger than the natural flood.Taking the Shibantan Reservoir in Guizhou Province as an example,the design flood results are calculated by superimposing the open-flow area and the underground river area upstream of the dam site respectively.Compared with the design flood calculated based on the whole basin,it shows that the design flood results are obviously larger when it is calculated based on the whole basin.The design flood result analyzed through superposition combination is close to the historical flood investigation data.