海岛地区小流域暴雨洪涝灾害模拟研究

Flood Disaster Simulation of Small Watershed in Island Areas

[目的]对海岛地区小流域暴雨洪涝灾害进行模拟研究,为该类地区后续开发建设以及防洪排涝治理工作的顺利开展提供技术支撑。[方法]选取浙江省舟山市朱家尖岛为研究对象,根据设计暴雨及设计和校核潮位资料,运用MIKE构建了一维河网模型、二维水动力模型以及MIKE FLOOD耦合计算模型,对比分析两种方案的淹没面积和水深、典型河道断面水位以及重点区域洪水演进过程。[结果]相对于设计暴雨及设计潮位条件下的方案1(94降雨+实测潮位),设计暴雨及校核潮位条件下的方案2(94降雨+极限潮位)在相对高水位时刻淹没面积更大,最大淹没深度更深。[结论]朱家尖流域内河流比降大,汇流时间短,流域调蓄能力差,抵抗暴雨产生的洪涝灾害的能力较弱。特别是暴雨遭受天文大潮时,研究区域受灾程度更重。

[Objective]The flood disaster in small watershed of island areas was simulated,in order to provide technical support for the subsequent development and construction of island areas and the smooth development of flood prevention and drainage management.[Methods]Taking Zhujiajian Island in Zhoushan City of Zhejiang Province as the research object,MIKE was used to establish a one-dimensional river network model,a two-dimensional hydrodynamic model and a coupling MIKE FLOOD model based on the data of design rainstorm,and the design and check tide level.The inundated area and the inundated water depth of the study area,the water level of the main river section,and the inundated duration of the key study area under these two schemes were compared and discussed.[Results]Compared with Scheme 1(94 rainfall+measured tide level)under the condition of designed rainstorm and tide level,the inundated area of Scheme 2(94 rainfall+extreme tide level)under the condition of design rainstorm and check tide level was larger and the maximum inundated water depth of the latter was deeper at the relatively high water level.[Conclusion]The flood control ability of Zhujiajian watershed caused by rainstorm is weak because of the large gradient ratio of rivers,the short confluence time,poor regulation and storage capacity.Especially when the rainstorm suffers astronomical spring tide,the disaster degree of the study area will be more serious.