Aplicação do modelo GR4J à bacia hidrográfica do rio Paraíba em Caraúbas.

Abstract

The rainfall-runoff modeling process has been an object of research for a long time and several models have been developed so far. From the simplest models based on empirical equations to the modern complex ones, these models differ in many aspects, among which are the greater or lower capacity to reproduce the observed (measured) rainfall runoff values and their ease of use. Prediction of extreme events, extension of runoff series, dimensioning, real-time prediction as well as evaluation of the use of land are found to be some of the main reasons for the development of rainfall-runoff models. This work was based on the GR4J (Genie Rural a 4 parametres Journalier) rainfall-runoff model, concentrated, on a daily base at the hydrographic basins of the Caraubas and Rio do Peixe Rivers, located at the Cariri and Sertao regions of the state of Paraiba, respectively. The main objective was to adjust, verify and validate this model for rainfall runoff prediction based on the knowledge about rainfall and use it in basins with similar climatic conditions to estimate inexistent runoff data. Satisfactory results were obtained when the model was applied to the Caraubas River basin for the 1996-1999 period, at this adjustment the Nash-Sutcliffe coefficient value was higher than 97%, however results were not found to be satisfactory when the model was adjusted for the Rio do Peixe basin, in which the Nash-Sutcliffe coefficient presented values below 70%.