Abstract's details
Hydrological dynamics of the floodplains in the Cuvette Centrale (Congo River Basin) using the Surface Water and Ocean Topography (SWOT) mission
Event: 2025 SWOT Science Team Meeting
Session: Hydrology: SWOT Lakes, Estuaries and Wetlands (SLEW)
Presentation type: Poster
Climate change is exerting significant pressure on all components of the Earth system, with surface water reservoirs—such as lakes, rivers, wetlands, and floodplains—being particularly affected. Within this hydrological compartment, wetlands, including floodplains, play a critical role in modulating hydrological processes. These systems function as natural buffers, storing substantial volumes of water over timescales ranging from weeks to months, thereby regulating river discharge, enhancing evapotranspiration, influencing regional energy and moisture fluxes and have a key role in the carbon cycle (Bar-on et al., 2025). Despite their importance, the spatio-temporal dynamics of floodplains remain inadequately characterized at both regional and global scales. This gap in understanding is primarily attributed to the high spatial resolution observations of inundation extent and surface water elevation.
In response to these limitations, the Surface Water and Ocean Topography (SWOT) mission—jointly developed by CNES and NASA, launched in December 2022—represents a major advancement. For the first time, this mission enables direct, high-resolution (∼100 m) and temporally consistent (21-day repeat cycle) observations of surface water extent and elevation over inland water bodies, including floodplains. This study aims to exploit the SWOT observations to monitor the hydrological dynamics of the Central Cuvette floodplain, a key component of the Congo Basin’s hydrological system. The Central Cuvette is located in the core of the Congo Basin in Central Africa with an area of approximately 1,176,000 km². The region’s climate is characterized by a humid tropical climate with bimodal rainfall distribution, featuring two pronounced precipitation maxima: one in October and a second in April. Consequently, the region exhibits a bimodal flooding regime, with peak inundation typically occurring during November–December and May–June, and low-flow periods observed in August and February–March (Betbeder et al., 2014 ; Normandin et al., 2024). The amplitude of surface water level fluctuations varies across the basin, with lower variability observed in the Cuvette Centrale, where annual changes range from approximately 1.5 to 4.5 meters (Kitambo et al., 2022a. Moreover, recent studies have provided quantitative estimates of surface water storage within the basin, reporting varying values, and have examined the influence of incorporating floodplains into surface water storage assessments (Becker et al., 2018; Frappart et al., 2021 ; Kitambo et al.,2022b).
More recently, a study conducted in the Congo Basin demonstrated the strong potential of the SWOT mission for measuring river slopes, even on rivers narrower than 100 meters (Normandin et al., 2024). This promising first step now allows us to focus on a more detailed analysis of floodplains in order to better quantify surface water storage and assess the full potential of the SWOT mission. The methodological approach involves the extraction and analysis of radar backscatter coefficients to delineate surface water bodies, followed by a comparative assessment with Synthetic Aperture Radar data from the Sentinel-1 satellite (Bossy et al., 2025). Preliminary results from this stage are currently under evaluation. Subsequent analyses will focus on the derivation and interpretation of water level and coherence maps, with the goal of improving our understanding of floodplain hydrodynamics in the Cuvette Centrale.
Back to the list of abstractIn response to these limitations, the Surface Water and Ocean Topography (SWOT) mission—jointly developed by CNES and NASA, launched in December 2022—represents a major advancement. For the first time, this mission enables direct, high-resolution (∼100 m) and temporally consistent (21-day repeat cycle) observations of surface water extent and elevation over inland water bodies, including floodplains. This study aims to exploit the SWOT observations to monitor the hydrological dynamics of the Central Cuvette floodplain, a key component of the Congo Basin’s hydrological system. The Central Cuvette is located in the core of the Congo Basin in Central Africa with an area of approximately 1,176,000 km². The region’s climate is characterized by a humid tropical climate with bimodal rainfall distribution, featuring two pronounced precipitation maxima: one in October and a second in April. Consequently, the region exhibits a bimodal flooding regime, with peak inundation typically occurring during November–December and May–June, and low-flow periods observed in August and February–March (Betbeder et al., 2014 ; Normandin et al., 2024). The amplitude of surface water level fluctuations varies across the basin, with lower variability observed in the Cuvette Centrale, where annual changes range from approximately 1.5 to 4.5 meters (Kitambo et al., 2022a. Moreover, recent studies have provided quantitative estimates of surface water storage within the basin, reporting varying values, and have examined the influence of incorporating floodplains into surface water storage assessments (Becker et al., 2018; Frappart et al., 2021 ; Kitambo et al.,2022b).
More recently, a study conducted in the Congo Basin demonstrated the strong potential of the SWOT mission for measuring river slopes, even on rivers narrower than 100 meters (Normandin et al., 2024). This promising first step now allows us to focus on a more detailed analysis of floodplains in order to better quantify surface water storage and assess the full potential of the SWOT mission. The methodological approach involves the extraction and analysis of radar backscatter coefficients to delineate surface water bodies, followed by a comparative assessment with Synthetic Aperture Radar data from the Sentinel-1 satellite (Bossy et al., 2025). Preliminary results from this stage are currently under evaluation. Subsequent analyses will focus on the derivation and interpretation of water level and coherence maps, with the goal of improving our understanding of floodplain hydrodynamics in the Cuvette Centrale.