Ferdinand N., Chaigneau Alexis, Kouraev A., Morel Y., Okpeitcha O. V., Biancamaria S., Ferrant Sylvain. (2025). Spatio-temporal variability of flooded areas in the Oueme floodplain (Benin, West Africa) from 2015 to 2023. Journal of Hydrology : Regional Studies, 62, p. 102965 [14 p.].
Titre du document
Spatio-temporal variability of flooded areas in the Oueme floodplain (Benin, West Africa) from 2015 to 2023
Ferdinand N., Chaigneau Alexis, Kouraev A., Morel Y., Okpeitcha O. V., Biancamaria S., Ferrant Sylvain
Source
Journal of Hydrology : Regional Studies, 2025,
62, p. 102965 [14 p.]
Study region: Oueme floodplain, southern Benin, West Africa. Study focus: The Oueme floodplain is a vast hydrological system feeding the Nokoue lagoon via the So and Oueme rivers, crossing an extensive wetland region. Driven by the African monsoon, this area is marked by pronounced seasonal and interannual hydrological variability, leading to recurrent flooding that significantly threatens local communities' safety and livelihoods. This study aims to assess the spatio-temporal variability of flooded areas in the Oueme floodplain from 2015 to 2023, using both in-situ measurements and satellite remote sensing. New hydrological insights for the region: The analysis reveals a clear seasonal cycle of flooding, modulated by interannual variability. Sentinel-1A data show that flood extent fluctuates widely, ranging from 20 to 160 km2, and identify the So region as the most flood-prone area. Importantly, the study detects a significant upward trend in flood extent over the study period. Flood dynamics are primarily governed by cumulative January-September rainfall, with a critical threshold of 1070 mm beyond which flooding expands rapidly. Altimetry data further indicate that a 6 m rise in water surface elevation north of the Oueme river results in increased flood expansion. Temporary hydrological connections appear during flood events, adding complexity to floodplain hydrodynamics and enhancing connectivity across the basin. Overall, this study provides new insights into the mechanisms driving floods in the Oueme floodplain using remote sensing.
