Avaliação de alternativas de uso do solo através da simulação hidrossedimentológica da bacia representativa de Sumé com modelo SWAT.

Abstract

The Brazilian semiarid area is one of the largest and most populous regions in the world, marked by scarcity, spatial and temporal variability of rainfall. Together with these climate characteristics, human settlement has triggered, through the deforestation of native vegetation and unsuitable soil handling, a process of degradation that compromises the environmental balance of the basins in these regions. The destruction of the caatinga, predominant vegetation in the Brazilian semiarid area, has lead to the acceleration of soil erosion, whose features reflect social, environmental and economical damage. The erosion can be minimized with the integrated use of conservation practices of land use that take into account its entire main physical attributes, ecological and economical representation. In this work, the need for adequately planning the use of the soil resources in the Brazil's semiarid, has impelled the adoption of the Soil and Water Assessment Tool - SWAT in the Representative Basin of Sume (RBS), located in the superior part of the Paraiba River basin- PB, as a tool for simulation of the runoff-erosion process for conservational planning of the use of soil in this basin. The model performance in the processes of parameterization and verification of consistency was analyzed through the coefficient of determination (R2) and Nash-Sutcliffe's coefficient of efficiency (NCE). The sceneries' simulation allowed us to evaluate how much the alterations of soil use and settlement interfere in the processes of superficial runoff and sediment yield, and proposed a simulation in the alternative scenery of the basin use featured as a conservational practice of vegetative desirability: reforestation. The obtained results show that the scenery which represents the whole preserved basin is the ideal condition in hydrological aspects, however, as the basin has areas with strong man's interventions, the proposal for reforestation is a plausible alternative in the conservational planning of the Representative Basin of Sume. Finally, the results obtained in this paper can be the basis for the analysis of alternative handling, aiming at the reduction of the impacts of man's activities in the watershed and supporting the planning of the use and management of basins in conservational bases.