Estimation of soil losses in the area of environmental protection of the Uberaba river

Abstract

Conservation Units are National Environment Policy instruments that determined the creation of areas for protection and guarantee of ecosystem balance in the Brazilian territory. The Uberaba River Environmental Protection Area (APA) is a water conservation unit in the city of Uberaba-MG. It is characterized as a sustainable use conservation unit, and some highly impacting activities have been occurring in this area, leading to erosion, water eutrophication, and changes in water quality and quantity. The aims of this study were to evaluate soil losses and to diagnose areas of natural potential for erosion (PNE) using the Universal Soil Loss Equation (USLE), the Geographic Information System (GIS), and remote sensing products. Adjusted PNE was low (<100 t ha-1 year-1) in 38.72% of the APA and moderate (100-200 t ha-1 year-1) in 31.29% of the area. High (200-600 t ha-1 year-1), very high (600-1000 t ha-1 year-1), and extremely high indexes (> 1000 t ha-1 year-1) were observed in 29.99% of the APA. Estimates of soil loss due to water erosion below 5 t ha-1 year-1 represented 43.81% of the APA. Estimated losses between 5 and 10 t ha-1 year-1 occur in 12.22% of the area; from 10 to 20 t ha-1 year-1, 21.82% of the area; between 20 and 50 t ha-1 year-1,17.89% of the area; from 50 to 100 t ha-1 year-1, 3.92% of the area; and losses over 100 t ha-1 year-1 involved 0.34% of the APA. The use of geotechnology, remote sensing products, geographic information systems, and the Universal Soil Loss Equation enabled spatial identification of sites of greater and lesser potential erosion risk, which enabling the estimation of soil loss rates throughout the Uberaba River Environmental Protection Area.