GALVÍNCIO, J. D.; http://lattes.cnpq.br/7217736964361440; GALVÍNCIO, Josiclêda Domiciano.
Résumé:
The need for rationalization of the use of water resources, in the semiarid area of the northeast
of Brazil, calls for an understanding of the interactions among climate, land use and
physiography. Considering the importance of an adequate water resources management, this
study examines the impacts of the spatial and temporal rainfall variability, soil depths and
vegetal cover on the water balance of a river basin. The catchment upstream of the Epitácio
Pessoa reservoir in the state of Paraíba is the nasin chosen for the current study due to its great
importance for the city of Campina Grande. Additionally, this study generates a data base of
physical characteristics and other data that include information on the topography, tributary
lengths, inclination, surface drainage direction, stream order, and total drainage area. The steps
involved in the development of this work are: initial data processing, identification of the
physical characteristics, vegetal cover estimation, and application of the water balance model.
The model is based on the identification and quantification of the hydrological processes in
seven different sceneries. In the model, the interception and evapotranspiration are considered
as losses. A program codified in FORTRAN, denominated TOPAZ (Topography
ParametriZation) and other softwares like Idrisi, Erdas, Surfer and Microdem were utilized in
this study. Landsat-TM 5 image, digital elevation data, daily rainfall, evaporation and
streamflow data were the main inputs. The results are displayed in digital map form, with the
identification major sub-basins. Among the various scenarios tested, the fifth represented best,
the surface runoff in the basin upstream of Caraúbas area. For the basin upstream of Poço de
Pedras, the sixth was the one that provided the bets results. In general, the model responded
well to the variability of the different factors in Epitácio Pessoa river basin, in spite of the
large spatial and temporal variability of rainfall. The adjusted model estimated that about 12%
of the rainfall is converted in to surface runoff. The Nash coefficient and the coefficient of
determination were on the average, 0,89 and 92%, respectively. When compared with the
observed flow series at Boqueirão de Cabaceiras between, 1932 –1955 the simulated surface
runoff indicated a retardation of the peak and a reduction in volume reflecting the effect of the
construction of many new storage dams within the basin that didn´t exist when the flow data
were registered..
