SOIL LOSS ESTIMATION IN A WATERSHED OF THE PARANÁ RIVER WITH DYSTROPHIC RED LATOSOL

Estimativa da perda de solo da Bacia Hidrográfica Córrego Santa Vera sobre Latossolo Vermelho Distrófico

Abstract

The hydroelectric power plants (HPP) in Ilha Solteira and Jupiá are part of the Urubupungá Hydroelectric Complex, which is the sixth most important hydroelectric complex in the world. However, their reservoirs are undergoing an intense siltation process. We evaluated the erosive potential of the Santa Vera Stream Watershed (SVSW), located on the banks of the Jupiá HPP reservoir. Soil use and occupation maps, and field analysis, enhanced by Geographic Information Systems (GIS), were used to obtain important parameters for the creation of RUSLE factors for the entire watershed. It was confirmed that areas dominated by degraded pastures that lacked conservation practices, such as contour lines, together with the increase in steepness of slopes toward areas near the drainage networks, resulted in higher estimates of soil loss. We concluded that the predominant values for soil loss estimates in the SVSW were low or close to zero. Nevertheless, values classified as being above soil recovery capacity were found in the reservoir banks, which lack riparian vegetation. Therefore, projects aiming at replenishing the vegetation of the reservoir banks are extremely important for their maintenance and for the conservation of native species in the region