MAPPING SOIL EROSION VULNERABILITY USING REMOTE SENSING AND GIS: A CASE STUDY OF MAMUABA WATERSHED, PARAÍBA STATE

Abstract

Soil erosion is one of the most significant environmental degradation processes. Mapping and assessment of soil erosion vulnerability is an important tool for planning and management of the natural resources. The objective of the present study was to apply the Universal Soil Loss Equation (USLE) using GIS tools to the Mamuaba watershed, southern Paraíba, for assess soil erosion vulnerability. An annual rainfall erosivity map was derived from the geographical model adjusted for northeastern Brazil, calculating an annual value for each pixel. The factors of soil erodibility (K), the topography (LS), and land use and management (C) were obtained in a GIS environment from soil type maps, digital elevation model (DEM) developed for the basin. The maps of the factors were combined to create the soil erosion vulnerability due to the water erosion. The results showed that, in general, the soils of the Mamuaba watershed present 54.54% of area with values between 0 and 10 t ha-1 year-1, which could be classified as "Slight to Moderate" to "Moderate" vulnerability in 1989, and 51.53% of the area in 2013. In the upper region of Mamuaba basin, the predominant classes were "Very High" and "Extremely High". High values of soil losses were predominance in regions of Red-Yellow Acrisol covered by pasture. Furthermore, the integration of USLE/GIS showed to be an efficient tool for the erosion prediction in this important basin of the Paraíba State.