Modelagem hidrossedimentológica e avaliação comparativa de três modelos em pequenas sub-bacias na região semiárida paraibana.

Abstract

In a region lacking water, knowledge of water-sedimentation processes is fundamental for the permanence and survival of man in the field. In this sense. The prediction of runoff and soil erosion in basins in semi-arid regions becomes indispensable in the processes of planning, exploitation and management of natural resources. Physically based hydrological models that can consider the effects of land use change provide through process modeling an excellent means to that end. In this work three distributed water-based hydrossedimentological models were applied in two sub-basins of the São João do Cariri Experimental Basin (BESJC) whose areas vary from 0.32 to 0.59 km2: the KINEROS2 (Kinematic Runoff and Erosion Model) model, the WESP model (Waiershad Erosion Simulation Program) and WEPP {Water Erosion Prediction Project). The application of the models was performed for several sub-basin discretization configurations. The results show that the three models are good for the prediction of the runoff in all cases. Regarding sediment production, WESP and KINEROS models provide good estimates of sediment at the individual event level and at the annual level. The WEPP model does not have adequate accuracy for small sediment yield values. The average saturation in the experimental units seems to have a scaling effect. The erodibility parameter due to the rain impact of the KINEROS2 model, ef also had some scale effect. The same scaling effect in the WESP model was verified in relation to the soil erodibility parameter K.