Sediment dynamics associated with managed realignment; Freiston shore, the wash, UK

The managed realignment (MR) undertaken at Freiston Shore has led to scour around the 14 breaches in the embankment, as well as an unforeseen enhancement in the development of a creek system on the mid-intertidal zone. This was related to the MR being at a lower elevation than the adjacent saltmarsh, causing high flows (3 ms(-1)) into the MR site during high spring tides; this was followed by a gradual release of the water volume throughout low water (0.2-0.5 ms(-1)). The width of the channels in the breaches increased by 15 m over 2 months. The majority of the sediment made available was deposited inside the MR site, which acted as an importer of sediment. The creek system on the intertidal zone experienced an increase in annual headward retreat, from 16 myr(-1) in the 10 years before, to 450 myr-1 in the 16 months following the MR.