Research on the Construction of Digital Watershed Model Based on DEM

The objective of this study is to construct a digital watershed based on DEM (Digital Elevation Model) [1], which is used to improve the spatial accuracy of hydrological modeling and the accuracy of flood forecasting. By utilizing DEM data, it is possible to portray the topographic features of the watershed in detail, thus simulating the water flow paths and confluence processes more accurately. In this study, a distributed hydrologic model was used to divide the watershed into subbasins and extract hydrologic elements, such as the river network, sub-basin boundaries, and confluence paths, using a terrain analysis algorithm. First, the DEM data were acquired and preprocessed [2] to ensure that their resolution and accuracy met the study requirements; second, topographic analysis was performed using a geographic information system (GIS) tool to extract the topographic information of the watershed; then, a digital watershed model was constructed based on the DEM [3] to generate sub-basin delineations and river network structures; finally, this spatial information was input into the hydrological model for flood forecasting simulation. The results show that the DEM-based digital watershed construction method can effectively improve the spatial accuracy of flood forecasting, and the simulation results have high consistency with the actual observation data, which can accurately reflect the hydrological change process of the watershed. This result provides a scientific basis for flood control decision-making and has important practical application value.