Um estudo dos efeitos de escala e uso do solo na parametrização do modelo NAVMO com dados de bacias do cariri paraibano.

Abstract

The effects of scale and land use change on the runoff generated in the watersheds of the semiarid region of the state of Paraiba are not well known. The deforestation impacts are principally on the processes of infiltration and runoff. In addition, the basin scale can affect the value of the parameters related to these processes due to the heterogeneities in the catchment (climate, soil, land use). In this research, the runoff curve number index (CN), introduced by the Soil Conservation Service of the United States, and the Manning roughness coefficient (n) that affect the infiltration and runoff characteristics are evaluated using data from the Representative Basin of Sume, measured at various basin scales, located in the semiarid northeastern region of the state of Paraiba, Brazil. Afterwards the validity of the parameters evaluated are analysed in the simulation of the runoff through the distributed model NAVMO, that consider such parameters as CW and n among others. investigation of the effects of scale and land use on the other parameters ofthe model, those for which the runoff generation is mostly sensitive, were carried out too. The results showed that the investigated parameters vary with the basin scale and land use condition. Also, the results demonstrated that the process of discharge is markedly affected by the land use, with the simulated maximum annual discharge and volume in deforested areas being 90% and 170 % greater than those simulated in forested ones.