Modeling of soil losses in the Camaquã River Hydrographic Basin, southern Brazil

Abstract

Water erosion is considered the main form of soil degradation of tropical and subtropical soils, causing the reduction of the productive capacity of the land and the eutrophication and silting of water bodies. However, the modeling of soil erosion is fundamental to design conservation practices of soils and waters. The objective of this work was to estimate soil losses in the Camaquã River Hydrographic Basin, located in southern Brazil, a region where water erosion is one of the main environmental problems. The modeling was performed using the Erosion Potential Method with the aid of geoprocessing techniques. The sediment delivery rate in the area was calculated from total sediment and flow data of the Camaquã River from a hydrosedimentological station. The Camaquã River Hydrographic Basin presented an estimated average soil loss of 7.4 Mg ha^-1 year^-1 and in 25% of the region the soil losses were higher than the tolerable limits. In the basin, a sediment delivery rate of 0.41 Mg ha^-1 year^-1 was observed, while the estimated value was 1.14 Mg ha^-1 year^-1. The identification of areas with high rates of soil losses due to water erosion, made in the present work, can help in the planning and management of soil conservation practices in the Camaquã River Hydrographic Basin.