Pattern Investigation of Beach Evolution in the Vicinity of Coastal Structures at Herne Bay, UK

In this paper we report on an investigation into the beach response within different parts of a coastal defence scheme. The study site is on the frontage of Herne Bay (Kent, South East Coast of England). The beaches along this segment of coast are mainly composite, with a shingle upper beach and sandy lower beach, or mixed sand and shingle. The dataset comprises detailed bathymetric surveys of beach profiles covering a period of over 10 years (∼3 beach surveys every year). New sea defences were constructed in 1993 along part of this frontage. Canonical Correlation Analysis, (CCA), is used to examine the relationship between beach responses within the scheme and also on stretches immediately updrift and downdrift. The results demonstrate that there are robust regression relationships between offshore wave conditions and local beach profiles. The statistical method was able to capture the different wave transformation effects at the three selected profiles, demonstrating that regional wave measurements were sufficient to form an understanding of local beach response. The significance of this result is that the current regional wave monitoring (as opposed to much more expensive local wave monitoring) is likely to be sufficient for coastal management purposes, with the caveat that the technique has been tried and tested on the Herne Bay site only. Interestingly, predictions using ‘offshore’ data provided reasonable predictions of beach response within the scheme without having to account for refraction of diffraction effects. This first application is encouraging and the results thought valuable to local authorities and consultants.