Nord G. auteur aut IRD Safdar S. auteur aut IRD Hasanyar M. auteur aut IRD Eze K. O. auteur aut IRD Biron Romain auteur aut IRD Freche G. auteur aut IRD Denis H. auteur aut IRD Legout C. auteur aut IRD Hauet A. auteur aut IRD Esteves Michel auteur aut IRD text journalArticle eng text/pdf born digital access This study presents a proof of concept of a reliable methodology for monitoring streamflow in a dynamic river of the Alps prone to bathymetric changes using non-contact instruments. The method relies on water level and surface velocity radar monitoring, discharge measurements by Large-Scale Particle Image Velocimetry (LSPIV), and topographic surveys. A single proportional relation, stable under bathymetric changes, is established between maximum surface velocity (Vs,max) and bulk velocity (Umean) using LSPIV measurements. The location of the maximum surface velocity is also shown to be relatively stable under bathymetric changes. The Isovel model, a theoretical approach which requires minimal information (i.e., bathymetry, water level and bed roughness) is also used to assess its capacity to predict the Vs,max-Umean relation and the location of the maximum surface velocity. Such model could be useful for applying the method in the absence of LSPIV measurements in the future. The applicability of the method is finally tested over a 2.5-year data set. Discharge is calculated at a time step of 10 min by multiplying the bulk velocity and the wetted cross-sectional area. The results are compared to the specific discharge time series at the historical station located 2.5 km further upstream, which has a stage-discharge rating curve, to assess the credibility of the proposed method. Good agreement is generally observed when surface velocity is above 0.7 m/s, but accuracy decreases for lower velocities. A simplified uncertainty analysis estimates a 25% relative error on discharge calculated with the presented method. specialized discharge surface water velocity river monitoring radar topography FRANCE GALABRE COURS D'EAU 062 020 61 4 e2024WR037536 [31 p.] 2025 0043-1397 https://www.documentation.ird.fr/hor/fdi:010093412 10.1029/2024wr037536 0043-1397 [F B010093412] https://www.documentation.ird.fr/hor/fdi:010093412 https://www.documentation.ird.fr/intranet/publi/2025-05/010093412.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2025-05-14 2025-11-04 fdi:010093412 fre