Ogilvie Andrew auteur aut IRD Belaud G. auteur aut IRD Massuel Sylvain auteur aut IRD Mulligan M. auteur aut IRD Le Goulven Patrick auteur aut IRD Malaterre P. O. auteur aut IRD Calvez Roger auteur aut IRD text journalArticle eng text/pdf born digital access Small reservoirs represent a critical water supply to millions of farmers across semi-arid regions, but their hydrological modelling suffers from data scarcity and highly variable and localised rainfall intensities. Increased availability of satellite imagery provide substantial opportunities but the monitoring of surface water resources is constrained by the small size and rapid flood declines in small reservoirs. To overcome remote sensing and hydrological modelling difficulties, the benefits of combining field data, numerical modelling and satellite observations to monitor small reservoirs were investigated. Building on substantial field data, coupled daily rainfall-runoff and water balance models were developed for 7 small reservoirs (1-10 ha) in semi arid Tunisia over 1999-2014. Surface water observations from MNDWI classifications on 546 Landsat TM, ETM + and OLI sensors were used to update model outputs through an Ensemble (n = 100) Kalman Filter over the 15 year period. The Ensemble Kalman Filter, providing near-real time corrections, reduced runoff errors by modulating incorrectly modelled rainfall events, while compensating for Landsat's limited temporal resolution and correcting classification outliers. Validated against long term hydrometric field data, daily volume root mean square errors (RMSE) decreased by 54% to 31200 m(3) across 7 lakes compared to the initial model forecast. The method reproduced the amplitude and timing of major floods and their decline phases, providing a valuable approach to improve hydrological monitoring (NSE increase from 0.64 up to 0.94) of flood dynamics in small water bodies. In the smallest and data-scarce lakes, higher temporal and spatial resolution time series are essential to improve monitoring accuracy. specialized Remote sensing Water balance Rainfall-runoff model Data assimilation Ensemble Kalman Filter Water harvesting TUNISIE ZONE SEMIARIDE 126 062 566 109-121 2018 0022-1694 https://www.documentation.ird.fr/hor/fdi:010074463 10.1016/j.jhydrol.2018.08.076 0022-1694 [F B010074463] https://www.documentation.ird.fr/hor/fdi:010074463 https://www.documentation.ird.fr/intranet/publi/2018/12/010074463.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2019-01-10 2023-07-11 fdi:010074463 fre