径流汇流模型在四川小流域山洪预警中的应用研究

Application of Runoff Confluence Model in Early Warning of Mountain Floods in Small Watersheds of Sichuan

以四川彭州山区小流域为研究对象,通过历史降水数据、流域分区数据、DEM等数据,对基于纳维-斯托克斯方程(N-S方程)稳定流场的流域径流汇流模型,进行参数率定,并在此基础上对彭州山区小流域山洪进行风险评估与预警。结论如下:①径流模型参数率定后扩散系数为0.12,加速系数为0.12,最大水速为3;②对不同降水小场景下汇流特征进行分析,发现随着雨量的增加,最大水深均在增加,且水深最大涨幅时间和水深最大时间均在减少,水深最大时间在200 min以内的流域主要为上游流域,而水深最大时间大于200 min流域主要为主流域;③通过评估得出彭州山区小流域山洪风险等级很高的流域为0个,山洪风险等级高的流域有17个,山洪风险等级较高的流域有19个,仅有1个流域山洪风险等级较低。

Taking a small watershed in the Pengzhou mountainous area of Sichuan as the research object,this paper employs historical precipitation data,watershed zoning data,DEM,and other data to calibrate the model parameters on a watershed runoff confluence model based on Navier-Stokes equation(N-S equation)with stable flow fields.The conclusions are as follows:①After model parameter calibration,the diffusion coefficient is 0.12,with an acceleration coefficient of 0.12 and a maximum water velocity of 3;②The analysis of confluence characteristics under different precipitation scenarios shows that with the increasing rainfall,the maximum water depth rises,and the time for maximum increase in water depth and the time for the maximum water depth decrease.The watersheds with the maximum time for a water depth of less than 200 min are mainly the upper watersheds,while those with the maximum time for a water depth of more than 200 min are mainly the main watersheds;③The assessment reveals that there are no watersheds with high risk levels of mountain floods in the small watershed of Pengzhou mountainous area,17 watersheds with high levels,19 watersheds with relatively high levels,and only one watershed with low levels.