Morphological and Sedimentological Changes on an Artificially Nourished Beach, Lincolnshire, UK.

Beach nourishment is increasingly seen as an appropriate management solution in areas which are experiencing beach erosion. Such a scheme has been implemented along the Lincolnshire coast between Skegness and Mablethorpe, on the east coast of England, since 1994. Poorly sorted, gravelly sandy sediment has been placed on the beaches in a gently sloping seaward profile to raise beach levels and protect the hard defences from wave attack. Grain size analysis of beach sediments, topographic profiling and remote sensing have been used to monitor the beach response. After nourishment, wave reworking caused a rapid redistribution of sediment over the beach profile during the succeeding weeks. Coarse sediment has remained on the beach berm, while finer sediment has migrated to the lower beach and sub-tidal zone. The berm face has correspondingly become steeper, producing more wave reflectance, and further scour and erosion of lower beach sediment, although there appears to have been little alongshore sediment transport. The most severe sediment loss has occurred around promontories and on the central portion of the convex-shaped coast which experiences greatest wave exposure. While the nourishment scheme has improved the standard of defence, further sediment losses could be reduced by nourishing the beach with a more natural size grading, promoting a flatter beach profile and increasing the dissipation of wave energy. Unless stabilization of the beach profile can be achieved, further periodic renourishment will be required to maintain relatively high beach levels. [ABSTRACT FROM AUTHOR]