Dynamic Perspective on the Capillary Barrier Effect at the Interface of an Upper Fine Layer with a Lower Coarse Layer

Morel-Seytoux, Hubert J.; ,

Dynamic Perspective on the Capillary Barrier Effect at the Interface of an Upper Fine Layer with a Lower Coarse Layer

by Hubert J. Morel-Seytoux, Hydrology Days Publications, Atherton, United States,

Document Type: Proceeding Paper

Part of: Engineering Hydrology

Abstract:

The theoretical principles behind the determination of infiltration rate into a coarse layer overlain by a tight layer are reviewed. As a descending unsaturated wetting front hits the interface, only a fraction of the water flux is transmitted to the coarse layer. The residual fraction is reflected and a ponded depth of water results over the interface. At first the transmitted fraction is very small but it gradually increases as the rising depth of water over the interface adds to the gravity drive. Eventually an equilibrium is reached, and the transmitted fraction stabilizes to its asymptotic limit. In this report it is assumed that the ponded water does not run off, which is somewhat unrealistic in hydrologic or low-level radioactive waste disposal problems. The analysis provides an insight toward a solution to more realistic problems. The physics and dynamics of the process are reviewed.

Return to search