Validation of SWAT+ Hydrological Model Using Remote Sensing-Based Evapotranspiration Data

This study evaluates the performance of the SWAT+ (Soil and Water Assessment Tool Plus) model in simulating evapotranspiration (ET) in the Tordera River Basin (Catalonia, Spain), a Mediterranean catchment with semi-arid conditions and complex topography, where accurate ET estimation is essential for sustainable water management. Model simulations (2003–2022) were validated against satellite-derived ET from the MODIS (Moderate Resolution Imaging Spectroradiometer) MOD16A2GF product, providing spatially distributed long-term reference data. Data processing, visualization, and statistical analyses were conducted using GIS and remote sensing tools (MiraMon) and R programming. MODIS-derived ET showed significant spatial and seasonal variability, revealing discrepancies with SWAT+ simulations and supporting improved validation protocols within the AquaINFRA project.