Assessing open-access digital elevation models for hydrological applications in a large scale plain: Drainage networks, shallow water bodies and vertical accuracy

This study evaluated six open-access digital elevation models (DEMs) for the Del Azul Creek Basin in the Argentine Chaco-Pampean Plain: Shuttle Radar Topography Mission, Advanced Land Observing Satellite Phased Array L-Band Synthetic Aperture Radar, TerraSAR-X Add-On for Digital Elevation Measurements (TanDEM-X), NASADEM Global DEM, Forest and Building height biases were removed from Copernicus GLO 30 DEM V1-0 (FABDEM), and TanDEM-X 30 m Edited DEM (EDEM). Statistical metrics were calculated for (i) residuals between DEMs and the Ice, Cloud and Land Elevation Satellite-2 (ICESat-2); (ii) the minimum distance between DEM-derived drainage networks and those from the Buenos Aires Provincial Water Authority; and (iii) DEM-derived slopes in shallow water bodies compared with the Joint Research Centre's Global Surface Water Mapping product. Analyses were performed for four elevation and seven slope bands. TanDEM-X had the smallest errors compared to ICESat-2 (median 0.19 m, NMAD 0.38 m), followed by FABDEM (median 0.31 m, NMAD 0.23 m). EDEM performed best in drainage networks (median 99.45 m, NMAD 117.16 m), followed by FABDEM. In general, the vertical error increased with elevation and the accuracy of the drainage network estimates improved. The vertical accuracy decreased with steeper slopes, with FABDEM performing the best across all slope ranges. FABDEM exhibited the best performance in determining seasonally dispersed shallow water bodies, demonstrating its overall usefulness for hydrological applications in large-scale plains characterized by aeolian geoforms of lowland accumulation and erosion. Assessing freely available products provides valuable resources for researchers and professionals and can guide decision making for managing hydrological resources, including flood risk and infrastructure development.