CHAPTER 10: COASTAL PROCESSES, PATTERNS AND LANDFORMS
Fig. 27 A beach in a sheltered bay in County Donegal
Fig. 26 The photograph shows some well-developed cusps on a shingle beach in County Louth.
O Sand spits
Main processes: longshore drift, constructive waves Example: Inch Strand, County Kerry. Sand spits are landforms of marine deposition. They are long deposits of sand attached to the land at one end. Portmarnock and North Bull Island in Dublin are well-known beaches which also happen to be sand spits. Sand spits are created when the process of longshore drift is
interrupted in some way either by a change in the shape of the coast or by human activity such as building a sea wall. They are commonly found attached to headlands.
IN DEPTH – Sand spits
Where the coast changes direction longshore drift is unable to move material further along the coast and the material is deposited at this point. Longshore drift continues to pile sand up here. Eventually a long ridge of sand extends out to sea and may be exposed at low tide. Over time the spit builds up, becoming visible at high tide.
Vegetation may grow, its roots stabilising the sand. Wind action may create sand dunes on the spit. Most spits have wide sandy beaches and dunes. Behind the dunes on the landward side a salt marsh may develop. Wave action and local currents often make the end of the spit
Fig. 28 Map showing bays, headlands and beaches between Rush and Skerries, County Dublin
curve, e.g. Inch Strand, County Kerry. One of Ireland’s best studied sand spits is the North Bull Island in Dublin. See the case study on page 181.