Natural erosion potential and the evolution of soil loss in the Arroio Quebrachinho watershed (1992–2022)

Abstract

Water erosion is one of the main forms of soil and water degradation. Mathematical models that identify areas most susceptible to this type of degradation can assist in land-use planning and in identifying the need to promote conservation practices. This study aimed to identify areas with natural erosion potential and to analyze the evolution of soil losses in the Arroio Quebrachinho watershed during the years 1992, 2002, 2012, and 2022, using geoprocessing techniques. The Universal Soil Loss Equation (USLE) factors were obtained from public-domain governmental databases, while the topographic factor (slope length and steepness) was derived from Digital Elevation Models (DEM) from the ALOS PALSAR sensor, with a spatial resolution of 12.5 meters. Throughout the analyzed timeframe, approximately 90% of soil losses were classified as “none” or “slight.” The discrete increase observed in the historical series may be associated with the expansion of temporary crops, especially soybeans. The advance of anthropized areas led to a reduction in “Grassland Formation,” which decreased by 23.1%. The areas most susceptible to soil loss were those with greater slopes, with 70% classified as “very low” and “low.” Although there is a predominance of low levels of erosion susceptibility in most of the watershed, the implementation of conservation practices is necessary to mitigate negative impacts on soil and water, aiming at the sustainability of these natural resources.