一种无资料地区山洪灾害临界雨量计算方法研究

An Approach to Determine Critical Precipitation of Mountain Torrential Flood Disaster in Ungauged Basins

临界雨量是预警山洪灾害的关键指标。山洪灾害多发生的无资料地区,其临界雨量的确定一直是防灾减灾中的难点。根据暴雨等值线图确定出的设计暴雨与设计洪水在工程实践中已广泛应用,因此,以设计暴雨与设计洪水资料为基础,率定出水文模型参数,再依据调查确定的成灾流量,计算出该防灾对象的临界雨量。选取二水源新安江与SCS两种水文模型,计算了湖北省宜昌市点军区内30个小流域的临界雨量,计算结果表明:1提出的方法对于无资料地区山洪灾害临界雨量计算具有可行性;2基于二水源新安江模型和SCS模型计算的临界雨量合理且二水源新安江模型优于SCS模型。

Critical precipitation is an important indicator during the process of preventing flash flood disasters.However,how to determine the value especially in ungauged basins is always challenging.Because the parameters of hydrological models used to calculate the critical precipitation cannot be calibrated.When we derive design storm and its corresponding design flood,the rainstorm isograph method is widely used in ungauged basins in engineering practice.Therefore,the design storm and its corresponding design flood are employed to calibrate the hydrological model parameters in our study,and the critical precipitation was determined when the disaster flow is input into the model.With a case study of Dianjun District,Yichang City,Hubei Province,Xin＇anjiang and SCS model are selected to assess critical precipitation respectively.The results indicate that the proposed method is conducive to determining the critical precipitation in ungauged basins.Both selected hydrological models are feasible to calculate the critical precipitation,but the Xin＇anjiang model has better performance than the SCS model in our case study.