基于HAND的流域洪水淹没快速分析技术

HAND-based Rapid Analysis Technology for Watershed Flood Inundation

快速分析计算流域洪水淹没,对于防洪具有重要作用,而基于水动力学模型的经典淹没算法在时效性方面存在不足,制约防洪“四预”功能实现和数字孪生流域建设。针对此,本文建立了基于HAND(Height Above Nearest Drainage)的形态淹没模型,用于快速分析流域洪水淹没情况,在乐安河流域上游进行了应用验证。结果表明,模型可在5秒内完成洪水淹没计算,对四场历史洪水和三场设计洪水淹没范围的总体模拟精度平均为0.95,达到水动力学模型的模拟精度;对淹没水深的模拟存在较大误差,平均误差为0.79 m。基于HAND的形态淹没模型可快速绘制全流域洪水淹没范围图,大幅提升影响预报和防洪预演的时效性水平。

Rapid analysis and calculation of flood inundation plays an important role in flood controlling.However,the classical hydrodynamic-based flood inundation mapping algorithms need high computational expense,hindering the realization of“Four-Pres”for flood control and construction of digital twin basins.Toward this end,this paper presents a morphological inundation model based on the height above nearest drainage(HAND)method to immediately analyze the flood inundation extent,which is demonstrated in the upstream of Le’an river basin.The findings indicate that the flood inundation mapping by HAND could be accomplished within 5 seconds with the overall accuracy for inundation extent reaching 0.95,which equals to the simulation accuracy by HEC-RAS.On the other hand,the model does not perform well in simulating water level in terms of that the average error is 0.79m.The HAND-based morphological inundation model enables rapid flood inundation mapping over basins with diverse scales,facilitating the speed and efficiency of influence-based forecasting and scenarios-based rehearsal for flood control.