Work

Assessing SWOT capabilities for monitoring floodplain water dynamics in the Paraná Basin

Year: 2026

Type: article

Abstract: The Surface Water and Ocean Topography (SWOT) mission provides unprecedented spatial coverage and temporal resolution of inland water surface elevation (WSE) and extent. This study examines SWOT high-rate raster product during a drought-to-flood transition in the Paraná River floodplain. SWOT observations are evaluated using in situ and satellite datasets, including multispectral imagery and nadir radar altimetry. These multi-sensor comparisons are used to characterize the spatial and temporal consistency of SWOT observations in floodplains under contrasting hydrological conditions, from disconnected low-water stages to widespread inundation. Results show that SWOT captures water level variability in channels with Pearson correlation coefficients exceeding 0.87 and mean absolute errors between 0.09 m and 0.21 m. Comparisons with Sentinel-6 A and Sentinel-3B reveal coherent WSE profiles (correlations up to 0.78) for transects covering channels and vegetated wetlands. Floodplain inundation extents derived from SWOT show high Precision (> 0.96) relative to multispectral products but moderate Recall (0.38-0.50 for GLAD), indicating inundated areas not detected by multispectral sensors. The inundated fraction detected only by SWOT increases with the flood pulse, reaching 53% of total water extent at peak flood in vegetated wetlands. These findings demonstrate SWOT's capability to monitor river-floodplain hydrodynamics and to improve large-scale water storage and budget assessments.

Source: Scientific Reports

DOI: 10.1038/s41598-026-53807-7

Authors: Edward Salameh, Lucas Sengsourinho, Cassandra Normandin, Valentine Sollier, Frédéric Frappart