基于HEC-RAS模型的青海省玉树县巴塘河流域洪水模拟分析

Flood Simulation and Analysis for Batang River Watershed in Yushu County Qinghai Province Based on HEC-RAS

青海玉树县地形起伏变化较大,具有明显的空间变异性,但传统的数值求解模型适用于近似一维的匀速正常水流,具有一定的局限性。因此,采用HEC-RAS模型,结合ArcGIS平台下的HEC-GeoRAS模块,建立二维流和非稳定流模型,对1981年至1982年青海省玉树县巴塘河流域的洪水进行模拟,并与实测数据进行对比分析。模拟结果表明:模拟的流量数据与观测数据变化趋势整体一致,且1981年和1982年的模拟流量峰值均出现在7月,与实测结果一致。对所建立HEC-RAS模型进行模拟精度评价,结果表明纳什效率系数和确定性系数均大于0.8,该模型可用于青海省玉树县巴塘河流域洪水的演进模拟分析。

The terrain fluctuation of Yushu County in Qinghai province is large and has obvious spatial variability,and there are limitations when using traditional numerical solution model to approximate one-dimensional uniform flow.Therefore,based on the HEC-RAS model and the HEC-GeoRAS module in ArcGIS platform,the two-dimensional and unsteady flow model is developed,and the floods in Yushu County Batang River basin of Qinghai Province from 1981 to 1982 have been simulated and compared with the measured data.The results show that the simulated flow data agrees well with the observed data,and the peak value of the simulated flow in 1981 and 1982 is in July,which is consistent with the measured results.The simulation accuracy evaluation of the established HEC-RAS model shows that both the Nash efficiency coefficient and the R2 are greater than 0.8,and the model can be used to simulate the flood evolution of Yushu County Batang River basin in Qinghai province.