Coastal Erosion in Northeast Ireland — Part I: Sand beaches, dunes and river mouths

Abstract

Shoreline erosion is an environmental issue in main parts of Ireland. This paper reports on a detailed study of shoreline change al sixteen beach sites from the mouth of Lough Foyle (Magilligan) in Co. Londonderry to Larne in Co. Antrim, a distance of 135km. Apart from a short stretch of coast (c. 4km) around the mouth of the River Bann, the entire coast is receding, although the rates of change and the reasons for such changes vary considerably. The most rapid erosion (up to 3.5 m/year) is occurring on the northwest coast of Magilligan, probably as part of a lone-term natural adjustment of the shoreline to secular climate and sea-level changes. Elsewhere, average erosion rates are much longer, often less than 0.25 m/year, although this rate approaches 1 m/year on those beaches (Cushendall and Cushendun) that are, or have been, used for sand and gravel extraction. In many places shoreline changes have resulted from human activities, including the building of seawalls, jetties and piers. At Portrush and Carnlough the beach level has fallen dramatically in front of the seawall. Both inshore dredging and the regulation of cross-shore stream discharge have affected shoreline stability in some areas, for example Portstewart and Ballycastle. Overall the causes of erosion arc often intermixed, and prediction of future trends is difficult.