Abstracted Modelling as a Tool for Understanding and Predicting Coastal Morphodynamics

• Published in: Journal of coastal research 2006-12, p.21-27
• Main Authors: Huntley, D.A, Coco, G., O'Hare, T.J.
• Format: Article
• Language: English
• Subjects: Beach cusps; Beaches; Hydrodynamics; Modeling; Randomness; Sediment transport; Shorelines; Splashing; Wavelengths; Waves
• ISSN: 0749-0208; 1551-5036

Understanding and predicting the morphodynamic behaviour of coastal features such as ripples, cusps and bars remain major challenges for coastal scientists and managers. One approach which is becoming more widely used is the development of 'abstracted' models, in which the processes driving the dynamics of the coastal system are described through a minimum number of variables and interactions which encapsulate non-linear feedbacks between hydrodynamic forcing and sediment response. In this paper we review examples of such models for coastal ripples, beach cusps and large-scale coastal bars. In each case, highly simplified abstractions of physical processes produce quasi-regular morphological features which are in remarkable agreement with observations, most notably in length scales and two-dimensional form. In the case of cusps the agreement has been shown to extend to quantitatively correct limits on conditions for the growth and suppression of the features. We conclude that abstracted models have considerable value in comparison with more 'traditional' modeling approaches. They provide indications of the essential minimum physical processes responsible for observed features. They also make direct use of stochastic forcing to provide time-domain simulation of the development of coastal morphology to finite amplitude and quasi-equilibrium forms. Their simplicity holds the promise of being able to study the statistical behaviour of coastal systems under a variety of forcing scenarios.