Land use and land cover changes impacts on the surface runoff and sediment yield in the Xingu river basin / Influência das mudanças do uso e cobertura da terra no escoamento superficial e produção de sedimentos na região da bacia do alto rio Xingu

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

This work had as objective to analyze the land use and land cover changes in the Suiá-Miçu river basin and to evaluate its impacts in the surface runoff generation and sediment yield. The Suiá-Miçu River is located in the north part of Mato Grosso State, it is a Xingu River tributary and is inserted in the Amazon River drainage basin. Three time periods were chosen in order to perform this study, 1973, 1984 and 2005. The surface runoff modeling was performed using the Automated Geospatial Watershed Assessment tool (AGWA), and the sediment yield was modeled using the Universal Soil Loss Equation (USLE). The data necessary to run the models includes land use and land cover maps, digital elevation model, precipitation data and soil maps. The results showed that until 1984, 13% of the natural vegetation of the study area was replaced by pasture. These changes resulted in a 5.4% increase in the surface runoff annual average when comparing with 1973, and the sediment yield increase along this same period reached 0.18 t/ha.ano in some regions. In 2005, the deforestation in the drainage basin reached 40% of the entire area, causing a 23% increase in the surface runoff generation compared to 1984 and in some regions the sediment yield was 7 t/ha.ano higher than in the previous analyzed period. Hence, the tools used in this work were efficient in the evaluation of the land use/land cover changes impacts in this region, confirming the vegetation cover importance in the maintenance of the natural hydrological cycle patterns and in the soil and natural resources conservation. In addition, this study indicated several limitations of these tools for use in quantitative studies that require more accurate results. The main restrictions found were related to the acquisition of digital elevation models that are capable of correctly represent the terrain slope, and in the implementation of soil maps with appropriated scales.

ASSUNTO(S)

deforestation desflorestamento erosion surface runoff amazônia legal erosão legal amazon escoamento superficial

ACESSO AO ARTIGO

Documentos Relacionados