Effect of Microtopography, Slope Length and Gradient, and Vegetative Cover on Overland Flow through Simulation
Publication: Journal of Hydrologic Engineering
Volume 9, Issue 5
Abstract
Overland flow on a hillslope is significantly influenced by its microtopography, slope length and gradient, and vegetative cover. A 1D kinematic wave model in conjunction with a revised form of the Green-Ampt infiltration equation was employed to evaluate the effect of these surface conditions. The effect of these conditions was treated through the resistance parameter in the kinematic wave model. The resistance in this paper was considered to be made up of grain resistance, form resistance, and wave resistance. It was found that irregular slopes with microtopography eroded more easily than did regular slopes. The effect of the slope gradient on flow velocity and flow shear stress could be negative or positive. With increasing slope gradient, the flow velocity and shear stress first increased to a peak value, then decreased again, suggesting that there exists a critical slope gradient for flow velocity and shear stress. The vegetative cover was found to protect soil from erosion primarily by enhancing erosion-resisting capacity rather than by decreasing the eroding capability of overland flow.
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Published In
Journal of Hydrologic Engineering
Volume 9 • Issue 5 • September 2004
Pages: 375 - 382
Copyright
Copyright © 2004 American Society of Civil Engineers.
History
Received: Apr 22, 2003
Accepted: Jan 16, 2004
Published online: Aug 16, 2004
Published in print: Sep 2004
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