Relação entre uso do solo e comportamento hidrológico na Bacia Hidrográfica do Ribeirão João Leite

Abstract

The hydrological behavior of watersheds derives mainly from climate variability and land use. The ‘Ribeirão João Leite’ watershed is the main sourse of water supply in Goiânia city, and recently intense modifications were observed in the land use and availability of water. In this context, this work proposes to classify the land use between 1979 and 2005 and establish the association of the runoff with the land use and climate variability. For this, Landsat images from the years 1979, 1989, 1997 and 2005 were used as well as flow and rainfall data provided by the Agência Nacional de Água (ANA). The land use was marked by 17.8% of deforestation, expansion of the urbanization and agriculture corresponded to 6.6 and 15.2%, respectively, and by significant areas of pasture. A trend of reduction in flow was observed that could be explained, in part, by a reduction in the rainfall regime. However, due to the significant increase of water withdrawal and the lack of historical records, there was difficulty in qualitative association between the runoff and the land use in spite of generating linear regression models with coefficients of determination (R²) above 0.75.