To mitigate the unavailability of accurate river channel terrain data for flood modeling, this work develops a new approach to construct channel terrain based on available global coarse digital elevation models (DEMs). Compared to other established methods, the approach constructs the river surface using the sparse cross-section data from available coarse DEMs and not measurements. For a 134 km river reach of the Yangtze River, the absolute percentage error of simulated peak discharge with the coarse DEMs is 76.77%, and the delay time of peak discharge is 13 h; however, with the reconstructed terrain data are 12.13% and 0 h. They are 9.70% and −1 h on a 382 km river reach. The simulation results show that the approach can be used to reliably predict the flood propagation process without fine terrain data. The proposed approach can be used to improve flood management in areas without fine river terrain data.

为了缓解无法使用准确的河道地形数据进行洪水建模的情况，这项工作开发了一种基于可用的全球粗略数字高程模型（DEM）构建河道地形的新方法。与其他已建立的方法相比，该方法使用来自可用粗略DEM而不是测量值的稀疏横截面数据构造河流表面。对于长江134 km河段，采用粗DEM的模拟洪峰流量的绝对百分比误差为76.77％，洪峰延迟时间为13 h。但是，重建后的地形数据为12.13％和0 h。它们是382公里河段的9.70％和-1小时。仿真结果表明，该方法可以在没有精细地形数据的情况下可靠地预测洪水的传播过程。