Conectividade da paisagem na bacia do rio sana (RJ): Relação entre áreas de captação efetiva e tipos de bloqueios

Abstract

Water and sediments transfer in a river system is influenced, among other aspects, by impediments that interrupt the transport of these materials and decrease the connectivity of the landscape in catchment. The study identifies the impediments nature and their influence on the effective catchment area and connectivity of the Sana Catchment, tributary of the Macaé River, located in the northern region of the state of Rio de Janeiro. The methodology set slope of hillslope as the main controlling factor of the process, establishes specifications for mapping impediments and effective catchment area, and indicates parameters for classification of the connectivity degree of catchment. Six types of impediments were identified, classified as buffer (disrupt the connectivity of the slope-channel) or barriers (interfering the water and sediments flow between tributaries - trunk stream), and then separately incorporated into the modeling of the effective catchment area, due to its peculiarities on the influence of the sediment and water contribution to the fluvial system. In this context, the Sana River Basin was considered connected when the Buffers were considered and disconnected, when Barriers were added to the model. Considering the results achieved, it can be said that the use of the connectivity approach in the catchment analysis scale was adequate, since it contemplates the natural and anthropic processes in the evolution of the landscape.