A hydrological-modeling study of the impact of land use/land cover and climate change on runoff in a watershed in the western Brazilian Amazonia | Um estudo de modelagem hidrológica do impacto do uso da terra / cobertura da terra e mudanças climáticas ..

In this work we investigate the effect of land use and land cover in the Jamari sub river basin, located in the Brazilian Amazonian. The objective is twofold: 1) to study the impact of deforestation and climate change on the basin's runoff, and 2) to test the feasibility of using a semi-distributed hydrological model for studying runoff of a low-slope river basin such as Jamari. We use a wide variety of data such as Landsat imagery, digital elevation data as well as conventional precipitation and near-surface data. We defined scenarios ranging from a completely forested basin to a completely man-modified one. In addition, we tested realistic scenarios for the ongoing deforestation process with 20% and 30% deforestation and tested scenarios hypothetic for climate change. Our scenarios suggest that for extreme and realistic scenarios there is an increase of runoff when deforestation occurs, since less water is intercepted in canopy, evapotranspiration and groundwater tends to decrease with deforestation. In climate change scenarios, increase temperature and precipitation tends to increase evapotranspiration and runoff and, increase temperature and decrease precipitation tend to increase evapotranspiration and decrease runoff and groundwater. The results suggest that Semi-distributed Land Use-based Runoff Processes (SLURP) is suitable for use in the Jamari sub river basin with the advantage of being a light model, in terms of internal parameters. The proposed methodology is suitable for use in other basins of the region