A unifying framework for shoreline migration: 1. Multiscale shoreline evolution on sedimentary coasts

摘要

A unifying framework for shoreline migration is presented which synthesizes problems from coastal engineering, geomorphology, and stratigraphy into a common quantitative basis. Consideration of characteristic problems from these fields reveals that multiscale shoreline evolution problems naturally break into three classes on the basis of the morphologicAinit of evolution: shoreface bed versus shoreline planform versus stratigraphic shoreline trajectory. Shoreline evolution models correspondingly break into morphodynamic, morphokinematic, and hybrid approaches. A generalized shoreline continuity equation is derived, the shoreline Exner equation, which subsumes equilibrium profile models commonly used in geomorphology and engineering and provides a natural framework for interpreting shoreline trajectories preserved in the sedimentary record. The shoreline Exner equation provides a rigorous basis for geometric and moving boundary models, which have significant untapped potential for shoreline migration problems. Recent advances in computational methods for evolving interface problems make hybrid models particularly attractive for problems of large-scale planform shoreline dynamics, such as delta evolution.