Austin

Bagnold

Butt

Clarke

Conley

Constantz

D. Pokrajac

Fand

Faybishenko

G. A. Kikkert

Horn

K. Steenhauer

Lara

Masselink

Nielsen

O'Donoghue

Puleo

T. O'Donoghue

Turner

van Gent

Journal of Geophysical Research Oceans

English

Crossref

Journal of Geophysical Research Atmospheres

Subsurface processes generated by bore-driven swash on coarse-grained beaches

Steenhauer, Kate

Pokrajac, Dubravka

O'Donoghue, Thomas

Kikkert, Gustaaf

The Open University

Air encapsulation during infiltration,

Beach formation by waves: Some model experiments in a wave tank,

Beach groundwater dynamics,

Breaking waves over a mild gravel slope: Experimental and numerical analysis,

Coastal Bottom Boundary Layers and Sediment Transport,

Coastal groundwater dynamics, paper presented at Coastal Dynamics ’97,

Estimating swash zone friction coefficients on a sandy beach,

Hydraulic behaviour of quasi‐saturated soils in the presence of entrapped air: Laboratory experiments,

Laboratory and numerical study of dambreak‐generated swash on impermeable slopes,

Measurement and modelling of gravel beach groundwater response to wave run‐up: Effects on beach profile changes,

Measurements and modelling of beach groundwater flow in the swash‐zone: A review,

Modelling flow in and above a porous beach,

Resistance to the flow of fluids through simple and complex porous media whose matrices are composed of randomly packed spheres,

Swash infiltration‐exfiltration and sediment transport,

Swash zone sediment transport, step dynamics and morphological response on a gravel beach,

Swash‐groundwater interaction on a steep gravel beach,

The influence of swash infiltration‐exfiltration on beach sediment transport: Onshore or offshore?,

The modelling of wave action on and in coastal structures,

The role of swash infiltration in determining the beach face gradient: A numerical study,

The total water content of sandy beaches,

Ventilated oscillatory boundary layers,

Large-scale laboratory experiments presented in this paper involved bore-driven swash on permeable immobile coarse-grained beaches. Two different sediments were used (d(50) = 1.5 and 8.5 mm) resulting in different beach permeability and surface roughness. The experiments yielded detailed measurements of swash depth and velocities, wetting front, pressure, and groundwater levels across the swash zone. This paper is focused on the processes occurring within the beach. The measurements provide the shape of the wetting front and the groundwater table and reveal the behavior of air in the unsaturated region of the beach. Air is initially at atmospheric pressure, but the pressure builds up when air becomes encapsulated between the saturated region formed below the swash and the groundwater table. For the 1.5 mm beach, entrapped air significantly affected the water exchange between the swash and the subsurface. The considerable buildup of interstitial air pressure reduced vertical hydraulic gradients and thus infiltration rates. At the lower end of the beach the hydraulic gradients even became negative, indicating flow reversal and exfiltration. In contrast, for the 8.5 mm beach the rate of infiltration was only slightly affected by the buildup of pore-air pressure. The vertical hydraulic gradients were more than twice the magnitude of those within the 1.5 mm beach. The results presented in the paper clarify the mechanisms that drive and impede the water exchange between the surface and subsurface flow. In particular, infiltration into the initially unsaturated part of the beach and the resulting air entrapment play a significant role in swash and similar flows

Subsurface processes generated by bore-driven swash on coarse-grained beaches

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The Open University

Hong Kong University of Science and Technology Institutional Repository