Finite Element Method and GIS Based Distributed Model for Soil Erosion and Sediment Yield in a Watershed |
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Authors: | M Gopal Naik E P Rao T I Eldho |
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Affiliation: | (1) Department of Civil Engineering, Indian Institute of Technology Bombay, Mumbai, India |
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Abstract: | The objective of this study is to develop a soil erosion and sediment yield model based on the kinematic wave approximation
using the finite element method, remote sensing and geographical information system (GIS) for calculating the soil erosion
and sediment yield in a watershed. Detachment of soil particles by overland flow occurs when the shear stress at the surface
overcomes the gravitational forces and cohesive forces on the particles. Deposition occurs when the sediment load is greater
than the transport capacity. Beasley et al.’s (Trans ASAE 23:938–944, 1980) transport equations for laminar and turbulent flow conditions are used to calculate the transport capacity. The model is
capable of handling distributed information about land use, slope, soil and Manning’s roughness. The model is applied to the
Catsop watershed in the Netherlands and the Harsul watershed in India. Remotely sensed data has been used to extract land
use/land cover map of the Harsul watershed, and other thematic maps are generated using the GIS. The simulated results for
both calibration and validation events are compared with the observed data for the watersheds and found to be reasonable.
Statistical evaluation of model performance has been carried out. Further, a sensitivity analysis has also been carried out
to study the effect of variation in model parameter values on computed volume of sediment, peak sediment and the time to peak
sediment. Sensitivity analysis has also been carried out for grid size variation and time step variation of the Catsop watershed.
The proposed model is useful in predicting the hydrographs and sedigraphs in the agricultural watersheds. |
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Keywords: | Kinematic wave approximation Finite element method Erosion Sediment yield Geographical information system Remote sensing |
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