Streamflow and sediment yield simulation within a small watershed through geoprocessing and modeling techniques. / Simulação de escoamento e de produção de sedimentos em uma microbacia hidrográfica utilizando técnicas de modelagem e geoprocessamento.
AUTOR(ES)
Ronalton Evandro Machado
DATA DE PUBLICAÇÃO
2002
RESUMO
Hydrological and water quality models have been developed to evaluate the nonpoint source pollution in agricultural watershed. With this objective, SWAT (Soil and Water Assessment Tool) model was applied to simulate the streamflow and sediment yield in Ribeirão dos Marins watershed, on the Piracicaba river basin, Brazil, for the period 1999/2000. The application of the model requires the input data in spatial format. The manipulation of these data was made with an interface between the model and the Geographic Information System (GIS) that, automatically, subdivides the basin in subbasins, from the Digital Terrain Model (DTM) and extracts the input data for each subbasin from the land use and soil layers. Later, the results of the simulation are presented in the format of maps, graphs and tables. The results of the simulation, monthly averages of the streamflow and the sediment yield, were compared to the observed data in a gauge station located in Ribeirão dos Marins watershed, using the Nash Sutcliffe Coefficient (COE) and the deviation of the simulated data in relation to the observed data (Dv). A calibration of some physical-hydrological parameters of soil and physical of the subbasins was made for the two variables simulated. Two alternative scenarios of land use have been simulated. In the first, the current land use was kept, with a riparian buffer of 30m along of the drainage network and of 50m around the springs, in accordance with the Forest Code. In the second scenario, as the pastures occupy the steepest hillsides, with high erosive potential, pastures were changed by native forest. The simulations of the two scenarios were compared to the current scenario, regarding the reduction of sediment yield. The results of the simulated streamflow were of 0,92 and 0,7% for the COE and the Dv, respectively, after the calibration. In the simulation of the sediment yield, after the calibration, the COE was 0,83 and Dv was 3,2%. The scenarios produced different spatial patterns of the sediment yield. The reduction in sediment yield of 84,4% was obtained with the substitution of the pasture by native vegetation (scenario 2). In scenario 1, the reduction was of 10,8%. These results show that is necessity to manage watershed considering the whole landscape aspects, identifying environmentally sensitive areas, mainly in relation to erosion, instead of protecting only riparian areas.
ASSUNTO(S)
gis (geografic information system) sedimentation geoprocessamento erosion sedimentação sig (sistema de informação geográfica) poluição difusa watershed non-point source pollution microbacia hidrográfica geotechnologies erosão
Documentos Relacionados
- Avaliação do potencial de produção de sedimentos na bacia hidrográfica do Rio Piçarras utilizando técnicas de modelagem e geoprocessamento
- Simulação de cenários alternativos de uso da terra em uma microbacia utilizando técnicas de modelagem e geoprocessamento
- Sediment yield modeling, through the MUSLE, in the Ribeirão dos Marins watershed, Piracicaba, SP
- Modelagem do escoamento superficial e erosÃo hÃdrica em uma microbacia hidrogrÃfica na regiÃo dos Tabuleiros Costeiros
- Simulação da produção de sedimentos para a microbacia hidrográfica do Ribeirão dos Marins (SP)