Omega, modelo de formulação não linear dos processos hidrológicos

Abstract

Hydrologic models, in general, perform a linearization of non-linear phenomena in such a way that the model becomes a simply parametric and numeric formulation. lnstead of that, OMEGA uses a more consistent mathematical representation of the physical processes in a hydrologic system. OMEGA model is strongly based on the physical concepts of hydrologic phenomena, even for the mathematical representation of highly nonlinear processes such as infiltration, saturation time and water redistribution on the soil. OMEGA accepts nonuniform values for precipitation and hydrologic parameters, and considers all the hydrologic processes as functions of the soil moisture. ln semiarid regions, as for example Northeast Brazil, the infiltration and evapotranspiration processes are specially important for the soil hydrodynamics. ln this kind of regions, soil moisture sometimes is extremely low and may cause significant variations of superficial run-off produced by intense precipitations after an excessive dry season. This phenomena is relatively frequent in the beginning of the rainy season. OMEGA model has been applied to Jatoba, a 28,6 Km2 subbasin, located in the Sume representative hydrographic basin, monitored by SUDENE under technical collaboration of ORSTOM. The results obtained in Jatoba have shown the consistency and accuracy of this methodology for a proper representation of the hydrologic processes and have been quite useful for the SUDENE and ORSTOM hydrologic analysis. Future applications of the present model to other representative basins in semiarid regions will be helpful to the understanding of the soil-water relationship and for forecasting purposes of hydrologic issues.