Geomorphometry-based modelling of discharge series in ungauged basins – Robustness regarding DEM sources

Abstract

Abstract. The sensitivity of a geomorphology-based hydrological modelling is evaluated according to four DEMs from 5 to 50 m resolution in Brittany, France. A set of 8 basins (5–565.7 km2) is used in a pseudo-ungauged context to explore the potential of Prediction in Ungauged Basin (PUB). The results show that despite slight differences on the stream networks extracted from DEMs and associated transfer functions, a coarse-worldwide DEM such as SRTM (25 m) supported similar performances than the finer French DEM (5 m) based on three validation indices. Finer DEMs may be useful only on headwater basins to gain a marginal performance.

Uptake by end-users of a PUB approach made available as a Web Service

“…This geomorphologybased hydrological approach (Cudennec, 2007) has been tested in different well described contexts with pseudoungauged strategies: semi-arid Tunisia (Boudhraâ et al, 2009(Boudhraâ et al, , 2018, temperate oceanic France (de Lavenne et al, 2015(de Lavenne et al, , 2016 and pluvio-nival Canadian Québec (Ecrepont et al, 2019). Robustness has been assessed regarding the calibration configuration (Boudhraâ et al, 2018;de Lavenne et al, 2016) and the resolution of the digital elevation model used as a geomorphometric reference (Ecrepont and Cudennec, 2020). Based on these grounds, simulations in truly ungauged catchments have been performed, in particular towards coastal bays (de Lavenne and Cudennec, 2019), which are water quality-related hotspots (Heal et al, 2021;Neville et al, 2022), being fragile fresh/marine water ecosystems where water-conveyed nutrient over-loads can induce eutrophication and green tides.…”

An end-user-friendly hydrological Web Service for hydrograph prediction in ungauged basins

“…The robustness of the approach to hydrometric configurations has been shown through sensitivity analysis and leave-one-out pseudo-ungauged tests (de Lavenne et al 2015, Boudhraâ et al 2018, Ecrepont et al 2019. Robustness to the resolution of the digital elevation model (DEM) used to characterize the geomorphometry has also been shown for Brittany (Ecrepont and Cudennec 2020). In addition, in the spirit of PUB, truly ungauged basins have been simulated between paired donor-target basins (de Lavenne and Cudennec 2014) and via ensemble modelling of multiple donor basins (de Lavenne and Cudennec 2019).…”