Changes since the Nineteenth Century to the Estuary-Barrier Complexes of North County Dublin

Abstract

Over the past 150 years, two estuary-barrier complexes on the north Dublin coastline have undergone considerable morphological changes. These include a reduction in the size of the estuaries, and estuary mouths, and the accretion of beach sediments and foredune ridges around the distal or southern ends of the barriers. Increased estuarine reclamation, and the construction of the Dublin to Belfast Railway across one of the estuaries, has reduced the volume of the tidal prism and weakened the ebb and flood currents, requiring an adjustment in the dimensions of the tidal channels and estuary mouths. Disruption of the tidal regime has led to substantial hydrodynamic and morphological changes, the southward extension of the barriers representing an attempt to restore the hydraulic equilibrium of these estuary/barrier complexes by reducing the cross section of the estuary mouth. Subsequent adjustments to these changes, combined with increasing recreational pressure, have been responsible for recent degradation and shoreline recession at the northern end of the barriers. A comprehensive understanding of the mechanisms of change currently operating along this coastline is essential to its effective management.