Surf Zone Conditions Research Articles

An energetics total load sediment transport model for a plane sloping beach

Bagnold's energetics‐based total load sediment transport model for streams is used as a basis for the development of a total load model of time varying sediment transport over a plane sloping bed. In both the bedload and suspended load, the transport rate vectors are found to be composed of a velocity‐induced component directed parallel to the instantaneous velocity vector and a gravity‐induced component directed down slope. The model is applied to idealized surfzone conditions, leading to estimates of the local longshore and onshore‐offshore sediment transport rates as well as the equilibrium beach slope as a function of the local wave and current conditions. The model is combined with a nonlinear longshore current model and spatially integrated to obtain predictions of the total longshore transport rate as a function of the incident wave conditions. The results support the general form of the wave power equation except that the wave power coefficient is no longer constant but is instead a complex function of the incident wave and beach characteristics.

Airborne synthetic aperture radar observation of surf zone conditions

Airborne synthetic aperture radar observation of surf zone conditions

Three Dimensional Beach-Stage Model

A three dimensional beach model applicable to open sandy coastal environments is presented. The model consists of ten beach stages incorporating erosional and accretionary sequences of beach-surfzone morphody-namic conditions. Each stage is associated with a particular level of breaker wave power. Decreasing breaker wave power produces spatially controlled onshore bar migration, eventual bar welding, beach accretion and reflective surfzone conditions ($$beach stages 6 \rightarrow 5 \rightarrow 4 \rightarrow 3 \rightarrow 2 \rightarrow 1$$). Increasing wave power generates beach erosion, dynamically controlled bar-channel formation and dissipative surfzone conditions (stages $$1 \rightarrow 2 \rightarrow 3 \rightarrow 4 \rightarrow 5 \rightarrow 6$$). Temporal variations in wave power cause predictable movement through and within the model. The effect of beach gradient (tan $$tan \beta$$) is considered with regard to the influence on the degree of dissipativeness, edge wave length and cut-off modes, and st...