Author
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SHARDA, V - DEHRADUN, INDIA |
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Nearing, Mark |
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Submitted to: International Soil Conservation Organization (ISCO)
Publication Type: Abstract Only Publication Acceptance Date: 5/23/1999 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: A finite element model simulating runoff and soil erosion from agricultural lands was developed by Sharda and Singh (1994). The sequential solutions of the governing differential equations of Richards with a sink term, Saint-Venant in conjunction with kinematic wave approximation, and sediment continuity were used to simulate infiltration and soil water dynamics under cropped conditions; overland and channel flow; and soil erosion, respectively. The sediment continuity equation was solved by employing a fully implicit scheme for time integration, Yalin's equation for sediment transport capacity, and inter-rill and rill relations of Foster (1982). The model reasonably simulated the runoff and erosion from agricultural lands treated with major mechanical soil and water conservation measures. For simulating rill erosion, the empirical relations evolved by Nearing (1997) and those used in the WEPP model were found to be in a reasonably good agreement through the latter has a tendency to slightly overpredict the peak sediment rate. The model of Nearing based upon stream power concept has the potential of better simulating rill erosion phenomenon due to its inherent advantage of knowing only the unit flow discharge rather than both hydraulic radius and velocity of flow. The comparison of predicted and observed sediment graphs has shown that sediment transport capacity simulated by simplified Yalin's equation (Finkner et al, 1989) was in close agreement with the solution of complete Yalin#s equation and the former can be conveniently used. The watershed model employing finite element technique has been tested under field conditions. |
