Comment on “Temporal geomorphic modifications and climate change impacts on the lower course of the São Francisco River, Brazil” by Torres et al. (2023)

Torres et al. (2023) argued that the Lower São Francisco River (LSFR) has undergone a significant morphosedimentary process in recent decades.The work applied remote sensing techniques in a multi-temporal analysis to quantify sedimentation and erosion processes.Moreover, the Modified Normalized Difference Water Index (MNDWI) demonstrates the narrowing of the channel.The authors examine how precipitation, runoff, MNDWI, and sedimentation affect each other.They found that less precipitation, less runoff, and more sedimentation are connected.However, the strategy of investigation and analysis of the results presents several inadequate aspects in the study of large tropical rivers.We argue here why the observation of increased sedimentation in the investigated area may not be considered valid for other areas of the LSFR.We also explain why the applied statistical relationship (precipitation, flow, and sedimentation) is inadequate.Our concern is that the use of results from an area that exhibits a transition zone specificity from the channel pattern can be used as for future interventions to restore a fluvial system as sensitive and complex as the São Francisco River.