Magnitude and Spatiotemporal Variation of the Erosion on the Slope of the Lower São Francisco River, Northeastern Brazil

Streams are under erosive processes such as hydrodynamic adjustment. After the construction of a sequence of hydroelectric dams for power generation, the São Francisco River experienced an increase in erosion processes, mainly on the riverbank of its lower course. The objective of this work was to quantify the magnitude and spatial and temporal variation of the erosive process. For this purpose, the erosion pins method was used on a vertical slope composed of Entisol, which was monitored monthly during the year 2013, alongside the acquisition of hydrological and meteorological data. The total soil loss was 35.26 m3, while the monthly magnitude of soil loss ranged from 0.00 to 24,300 mm yr-1, totaling 475,396.1 mm yr-1. The hydrodynamic and geometric characteristics of the watercourse, such as discharge and the proximity of the riverbank from the thalweg, are cited as the main causes of this erosion process.