SEEPAGE EFFECTS ON SEDIMENT TRANSPORT BY WAVES AND CURRENTS

T.E. Baldock, P. Holmes

Abstract


This paper considers the influence of seepage on the motion and transport of sediment. Under wave motion, steady upwards seepage (injection) increased erosion, while downwards seepage (suction) stabilised the bed. Conversely, seepage in the presence of a steady flow produced negligible changes in the sediment motion. A theoretical analysis examines the stability of the sediment particles and sediment bed under these conditions and provides an explanation for the different seepage effects. Seepage across the sediment/fluid interface also had a strong influence on the growth of sand ripples, even at pressure gradients of order 0.1. These results suggest that ripple dynamics in the nearshore may be affected by the watertable level and drainage within a beach.

Keywords


seepage effects; sediment transport; current

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