INFLUENCE OF LAND USE CHANGE ON SEDIMENT YIELD: A CASE STUDY OF THE SUB-MIDDLE OF THE SÃO Francisco River Basin

Abstract

ABTSRACT Erosion risk mapping and assessment are important for planning of natural resource management tool. The objective of this study was to simulate different scenarios of land use in the Sub-Middle of the São Francisco River Basin using the Soil and Water Assessment (SWAT) model to analyze the effects of changes in sediment yield, making comparisons with the present land use classification. The scenario analysis was (i) vegetation type characteristic of the semiarid region, (ii) growing corn and (iii) bare soil. For calibration procedure, the first three years of time series from 1993 to 1994 were validated using data from 1995 to 2004. The SWAT model employs the Modified Universal Soil Loss Equation (MUSLE) to compute soil erosion data. The results of simulations for different land uses allowed the identification of areas with a high potential for erosion by water. The major impact produced by sediment inflow was in the bare soil scenario, corresponding to an increase of 93.7% over the current land use. The landscape management in river basins using SWAT model can help identify areas particularly susceptible to erosion process.

Keywords

• hydrologic modeling
• evapotranspiration
• runoff
• SWAT model