基于半分布式水文模型的小流域山洪临界雨量指标计算

Calculation on the Critical Rainfall Indexes of the Small Watershed Based on Semi-Distributed Hydrological Model

基于半分布式水文模型的山丘区小流域防灾对象的雨量预警指标计算方法,首先采用NAM建立小流域半分布式水文模型,结合场次暴雨洪水数据分别对模型进行率定;根据沿河居民户与河道的空间分布信息,建立洪水水面线-沿线居民户高程判定模型,定位防洪能力最薄弱的居民户,确定成灾水位,以水位流量反推法推算防灾对象的成灾流量;采用模型试算法计算临界雨量。以南高而、柳埠东两个小流域为应用实例计算其临界雨量,并采用1995~2014年的75场降雨为验证数据系列,将计算的雨量预警指标与实际灾情对应的雨量记录进行对比验证。结果表明:该方法计算的临界雨量准确率在80%以上,能较好地应用于山洪灾害预警。

This study proposed a rainfall early warning indexes calculation method on the disaster prevention objects in the small watersheds of the hilly area based on the semi-distributed hydrological model.Firstly,NAM was used to establish a semi-distributed hydrological model of small watersheds,and the model was calibrated by combining the storm flood data.Besides,it established the model of the flood water surface line-the households elevation along the line based on the spatial distribution of the rivers and the households along it.The weakest flood control capacity of the households was located to determine the water stage,and the reverse calculation method of water stage and discharge was used to calculate the disaster prevention objects,and the model test algorithm method was used to calculate critical rainfall.Taking Nangaoer and Liubudong small watersheds as the cases to calculate its critical rainfall,and the calculated rainfall early warning indexes were compared with the observed rainfall based on the verified data series of 75 rainfalls during 1995-2014.The results show that the accuracy of the critical rainfall is above 80%that can be applied to the early warning of the flash disasters.