Superposition-based approach to generating river bathymetry: A case study

Abstract

The accuracy of two- or three-dimensional hydraulic modelling of river flow depends significantly on a realistic description of river channel and floodplain geometries in the form of a continuous, seamless topobathymetry digital elevation model (TB-DEM). However, bathymetric information for most rivers is not available in ready-to-use digital data format. The existing methods of generating TB-DEMs require access to raw data and ground measurements to some extent. This study proposed a simple superposition-based approach, comprising geographic information system-based interpolation and geoprocessing techniques to generate a seamless elevation model using topography and bathymetry from secondary data sources, including crowdsourcing. TB-DEM was generated for the St. Lawrence River and Ottawa River upstream of Montreal in Quebec. The upland topography was unaffected by the superpositioning process, whereas the interpolated bathymetry showed significant positive linear associations with the reference elevation data. The vertical accuracy of the bathymetry digital elevation model was 1.43 m in root-mean-squared error.