Effect of hysteresis and rainfall intensity on finger dynamics

Abstract

AbstractThe purpose of this paper is to present sand‐box experiments and a hysteresis model to explain the formation and hydraulic properties of fingered flow. Previous researches have found that a fingered path persists over long periods of constant infiltration; hysteresis could be an important factor. In this paper, a major point is to utilize the boundary and series internal scanning curves of the hysteresis model derived by Huang et al. (2005) to clearly obtain the variations between soil water content (θ) and matric suction head (ψ). The hydraulic properties of fingered flow are also acquired. For the application of the model in the field, the hysteresis curves derived by Hogarth et al. (1988) are compared. Experimental results verified that both hysteresis models and the present soil water content concept model of fingered flow can be adequately applied in field tests. We attempted to use digital image analysis to visualize and determine soil water content of fingered flow easily and quickly. The initial velocity and width of fingered flow were not constant under consistent rainfall intensity. The present concept model showed the matric suction head is uniform between different soil water content sharply in the horizontal direction. Nonuniform soil water content existed even when the potential was horizontally equalized. Copyright © 2008 John Wiley & Sons, Ltd.