The profile changes calculated by XBeach are largely consistent with the description of dune evolution given by Jiménez et al (2006). Jiménez et al observed that profile A became flatter, with large quantities of eroded sediment deposited on the back side of the barrier island, due to the consistent wave over-topping. The model replicates this behaviour, except that the island is lowered more than in the measurements and that the seaward face of the island does not roll back as it does in the measurements.
The observed response of profile B1 was dune face retreat, overwash deposition in the dune valley between the primary and secondary dunes and narrowing of the island, Jiménez et al (2006) also noted decrease of the beach face slope. It can be seen in \autoref{fig:Assateague_Island_profiles.eps} that the morphological development of the island is well represented by the model. The simulated dune crest retreat corresponds closely to the measured retreat. Overwash takes place in the model and sediment is deposited in the valley between the primary and secondary dunes, although the magnitude of deposition is less than in the measurements.
The XBeach model of profile B2 shows a slope reduction on the seaward side and lowering of the seaward dune. The second dune crest retains its crest level as described in the work of Jiménez et al (2006). The beach slope decrease in the XBeach model is in line with the description given by Jiménez et al (2006), but differs from their measured profile. It is unclear why the measured profile shows almost no erosion of the beach face.
Jimenez et al. (2006) observed, in general, profile C to lower in height, the seaward dune slope to become smaller, and seaside retreat of the shoreline resulting in barrier narrowing. The XBeach model shows retreat of the upper dune face and a reduction of the seaward dune slope. The model over predicts the sedimentation at the base of the dune and under predicts the crest lowering.