Comparison of three longshore sediment transport rate formulae in shoreline evolution modeling near stream mouths

Longshore sediment transport (LST) rate is the most essential quantity to be defined in shoreline evolution models. Intercomparisons of different formulae on the basis of laboratory or field measurements of LST rate values are commonly found in literature; however, examples of comparison based on long-term shoreline evolution observations are scarce. Moreover, applications of shoreline evolution models near stream mouths (where the sediment input affects coastal morphology) are also scarce. In the present paper, three well-known LST rate formulae are compared, as part of a model used to simulate shoreline evolution in the vicinity of a stream mouth. The model was properly adapted by the authors to provide with new capabilities regarding: (a1) the use of wind data to simulate wave climate, (b1) the description of coastal morphology and sediment transport and (c1) the introduction of sediment sources. Results show the relative efficiency of the three formulae in terms of: (a2) the stream sediment discharge needed to simulate measured shorelines, and (b2) the divergence observed between simulations and measurements; analysis is deemed to provide a useful perspective on the importance of LST rate formula selection in similar engineering applications.