基于山洪灾害事件的小流域临界雨量检验复核

Early-Warning Index Inspection Review of Small Watershed Based on Mountain Torrent Disaster Events

针对无资料小流域山洪灾害临界雨量确定中存在的问题,基于山洪灾害事件和洪水调查资料,引入频率区间和偏离度概念,通过成灾洪水雨量特征值与临界雨量的比较,初步检验临界雨量;针对引起临界雨量误差的主要因素,通过复核比降、糙率、水位—流量关系和流域产汇流计算方法及参数,间接复核临界雨量。以安阳县许家沟乡河西村河西沟小流域为实例进行应用研究,结果表明:河西沟小流域以0.8倍流域最大蓄水容量为前期影响雨量所对应的1 h临界雨量较为合理,但2 h临界雨量偏小31.2%;复核发现河西沟小流域水位—流量关系和产流计算方案均存在一定的误差,导致2 h临界雨量偏小较多。复核后以0.8倍流域最大蓄水容量为前期影响雨量所对应的1 h和2 h临界雨量偏差均在允许范围内,预警精度明显提高,表明该方法用于山洪临界雨量检验复核在技术上是可行的。

The problems existing in the determination of early warning index of mountain torrent disasters in small watershed without data,this paper presented information based on flash flood disaster and flood investigation,introduced the concept of frequency range and deviation,comparison of eigenvalue and critical rainfall of flooded rainfall,preliminary inspection of early warning indicators; aiming at the main factors that cause the error of early warning index,through the analysis of water flow relationship between rationality of the slope,roughness,runoff and confluence calculation method and parameters,indirectly review of early warning indicators. This paper studied Hexigou small watershed in Hexi Village,Xujiagou Town of Anyang County. The results show that Hexi Village under 0.8 Wm 1 h critical rainfall is more reasonable,but 2 h smaller by 31.2%; review finds out that the relationship between water flow and runoff in Hexi Village exists error,leading to2 h early warning indicators much smaller. After review 0.8 Wm 1 h and 2 h critical rainfall deviation is within the allowable range and warning accuracy improved significantly,showing this method is feasible for the detection of critical rainfall in mountain torrents.