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Recently, the SANTOSS practical sand transport model was developed. This paper describes the implementation and testing of this formula in the Delft3D morphological modeling system. This is done based on a compressive set of hydrodynamic and sand transport from two largedata Delta Flume -scale experiments. It is shown that the measured net transport is a delicate balance between offshoredirected suspended load due to undertow and onshore- -directed near-bed transport due to wave asymmetry and skewness effects. The Delft3D model is able to reproduce the importance of current-related suspended load the for the highwave cases (leading to offshore breaker - migration), as well as the bar onshore net transport for the lower-wave case (onshore bar migration). The mismatch between measured andcalculated near -bed transport is most apparent near the breaker bar. 1. Introduction Engineering morphological models (e.g. Delft3D, Mike, Telemac) are frequently used in coastal engineering practice to predict coastal evolution due to the combined influence of natural processes and human interferences. The resolved physics are fairly simple to keep computational times within practical limits, and therefore these models include a large number of parameterisations to account for unresolved processes. These parameterisations are usually not very well-founded on experimental data nor on fundamental understanding of the underlying hydrodynamic and sand transport processes. This especially applies to wave-driven cross-shore processes that are highly variable in time and space. As a consequence, the performance of engineering models in predicting beach and shoreline evolution is poor. For example, Van Rijn et al. (2011) showed that Delft3D systematically overpredicted measured beach erosion. This mismatch was so severe for accretive, low-wave conditions that the initial bed level was a better prediction of the final bed level than the Delft3D computation. 100 17/03/201514 pp |
