SEDIMENT TRANSPORT DYNAMICS ACROSS SHORE-ATTACHED SAND RIDGES

As sea levels rise many coastal areas are predicted to experience beach erosion. However, this erosion can potentially be partially mitigated by natural onshore transport from offshore sediment reserves. While offshore sediment reserves have been recognized as a potential source of sediment, the mechanisms by which this sediment makes its way toward the coast (often up- slope) where it can be further transported onto beach has been less well studied. Further the non-linear wave motions that have primarily been hypothesized to drive onshore transport (e.g. Elgar et al., 2001) are poorly resolved in most phase-averaged (spectral) wave models used to simulate coastal change over management timescales. Here, using co-located and contemporaneous observations of sea floor sediment mobility (via bedform migration) and near-bed velocity, we aim to understand the physical drivers of onshore sediment transport across shallow shore attached sand ridges.