Avaliação hidrossedimentológica de uma bacia sem dados de vazão utilizando o modelo SWAT.

Abstract

Disorganized population growth coupled with the intensification of human activities is accelerating changes in natural ecosystems, leading to a number of environmental problems, in particular water resources. The need of mankind for this resource has been growing rapidly and incompatible with nature's capacity for recovery, causing scarcity and damage in its quality. In addition, the various purposes for which these resources are used have generated a large number of use conflicts and also qualitative and quantitative degradation of water bodies. In the Brazilian semi-arid, the situation of water scarcity compromises the economic and social development of the region. Thus, it is necessary to develop adequate tools to support the decision making regarding the use of water resources. Changes in soil use and occupation affect the behavior of surface runoff, and the analysis of trends in water flow is important for planning the use of water resources and soil. Variations in pluviometric regime due to climate change also affect water availability in river basins. This work aims to model the processes of generation of runoff, soil erosion and potential underground recharge in the Sucuru River basin downstream of the Sumé-PB dam using the SWAT model. Precipitation and temperature data were used from 1994 to 2015, as well as maps of soil types, land use and occupation with changes observed in the period. The parameters CANMAX, GWQMN, GW_REVAP, ESCO, EPCO and CN were identified as the most influential on the process of generation of surface runoff. The value of the GWQMN parameter was set at 2000 mm, since no survey conducted in the basin indicates a soil depth greater than 2.0 m. The parameters CANMX, ESCO, EPCO and CN were very influential, because any small changes for more or less, caused an overestimation and / or underestimation of the drained sheet, thus requiring many attempts before obtaining their final values. The results demonstrate the efficiency of the SWAT model in quantifying and comparing the hydrosedimentological processes in the Paraíba region. The contribution of this work is given by the formulation of a methodology for the realization of hydrosedimentological studies in regions where there is no data of surface runoff or sediment production.