COASTAL DUNE EROSION AT FORMBY POINT, NORTH MERSEYSIDE, ENGLAND - CAUSES AND MECHANISMS

Following a period of coastal progradation during the nineteenth centu ry, since ca. 1900 a 5 km length of dune-fronted shoreline at Formby P oint, located between the Ribble and Mersey estuaries in northwest Eng land, has been eroding at an average rate of up to 3 m/yr. Although se veral factors probably contributed to the onset of erosion, meteorolog ical records suggest that a high frequency of strong westerly winds (a nd, by inference, storm waves) around the turn of the century played a n important role. The erosional trend was reinforced by the effects of training wall construction and dredge spoil dumping which changed the bathymetry in Liverpool Bay and led to greater focussing of wave ener gy onto the north-central part of Formby Point. Sand eroded from this part of the shore has been transported by longshore drift northwards a nd southwards away from the Point, leading to beach and foredune accre tion between Ainsdale and Southport and at Altcar. Foredune erosion at Formby Point was also accelerated between 1900 and the mid-1970s by t he abandonment of dune and foreshore management which had been extensi vely practised during the late 19th century, and by a significant incr ease in recreational pressure, sand mining and military activities. Si nce the instigation of a Coastal Management Scheme in 1977, damage to the dunes from these causes has been greatly reduced, but the dune pro tection and restoration works employed have had little effect on the u nderlying problem of beach and foredune erosion by waves, especially d uring storm surges.