Representação dos processos hidrológicos em bacia hidrográfica do semiárido paraibano com modelagem hidrológica distribuída

Abstract

The large-scale distributed hydrological model MGB-IPH has been applied to several Brazilian watersheds with acceptable results. However, the applicability of this model to watersheds with intermittent rivers, typically occurring in the Brazilian semiarid region, is questioned and limited evaluation has been carried out. This research analyzes the performance and applicability of the MGB-IPH model in representing the spatio-temporal patterns of hydrological processes in the Piancó catchment (PB), upstream from the Piancó streamgauge station (drainage area of 4,603 km2). The MGB-IPH was run for a 42-year period (1970 to 2011) with a daily time step and regular grid cells (5 × 5 km. The model was able to satisfactorily reproduce daily and monthly observed hydrographs, obtaining skill scores equivalent to other model applications for perennial rivers, as well as comparable to the performance of an earlier study developed in this same catchment area (but carried out with a monthly time step and applying different hydrologic models). No systematic error of the model for overor underestimating the discharges was observed. The hydrological processes intermediate to the rainfall-runoff transformation (evapotranspiration, soil water storage and runoff generation) were coherent in terms of seasonality, magnitude and spatial distribution over the catchment area.