Coastline of Wales

The coastline of Wales extends from the

Parts of the Welsh coast are formed by

In common with other parts of Britain and Ireland, Wales has experienced significant changes in sea level in the last few tens of thousands of years, largely attributable to the waxing and waning of ice sheets during successive glacial periods, the last of which ended only 11,500 years ago. At the height of the last ice age, the volumes of water locked away as ice resulted in a drop in global sea level which has been estimated at between 105 metres and 123m (345' and 404') and a corresponding change in the position of the coast. During this period of lowered sea level, the lower sections of many rivers were rejuvenated and they cut down into their beds as evidenced by the buried channels of the Usk at Newport and the Wye at Chepstow which are more than 20 metres and 17 metres (65' and 55') below sea level respectively.^[3] The Flandrian transgression associated with the melting of the ice-sheets has brought the sea level to that recorded over human history, with the larger part of that rise achieved prior to 6000 years ago. Within Cardigan Bay, three 'sarnau' or causeways - Sarn Badrig, Sarn Gynfelyn and Sarn y Bwch - extend out from the coast for several miles, parts being exposed at low spring tide. These are interpreted as medial moraines left by ice moving west off the Cambrian Mountains during the last ice age. The position and character of the modern coastline owes much to the manner in which sea level has adjusted since.^[4]

Peat deposits and tree stumps are exposed in the intertidal zone in many places along the Welsh coast. They date from a time of lower sea level around 8000 years ago. The traditional Welsh legend of the drowned land of Cantre'r Gwaelod has been linked to these localities.^[5] A stormier climate between about 1300 and 1700 led to large quantities of sand being blown onshore and increasing the size of the various dune systems.^[6]

Tidal range

Cardigan Bay experiences the lowest tidal range along the Welsh coast (less than 3 metres; 10') whilst the Bristol Channel coast experiences the highest (up to 14m).^[7] Indeed, the tidal range within the funnel-shaped estuary is the third or fourth highest in the world.^[8] A result is that the intertidal zone is larger than might otherwise be the case.^[9]

Shore platforms

'

There are a large number of

The county of Pembrokeshire forms the largest peninsula in Wales and contains within it, several smaller peninsulas such as the Dale peninsula and St David's peninsula; the headland of

Cardigan Bay is much the largest bay on the Welsh coast but dozens of others are found at a variety of scales.

Dune systems

Major dune systems occur at intervals around most of the Welsh coast. The majority are "bay dunes" as commonly found around the Pembrokeshire coast. Some, known as "hindshore dune systems", occur where the prevailing wind has driven sand inland as at

Salt marshes are found in many areas. Amongst the most significant are those on the southern side of the Loughor estuary on Gower's north coast. Significant areas of salt marsh are also found within the Dee estuary and between Harlech and Porthmadog though, here as elsewhere, reclamation of large parts of the marsh have taken place in the past for use as farmland.

Islands

Anglesey is easily the largest Welsh island, separated from the mainland in the northwest of the country by the Menai Strait (Welsh: afon Menai). Smaller islands off Anglesey include Wales' second largest,

Off the coast of Llŷn are Bardsey Island (Ynys Enlli),

Much of the population of Wales live in coastal communities; its three largest cities, Cardiff, Swansea and Newport are on the coast.

Ports

The two largest passenger ports are Holyhead and Fishguard which are the eastern termini of the two

A number of seaside resorts developed during the Victorian era including Rhyl, Prestatyn, Colwyn Bay, Llandudno, Tenby, Porthcawl and Mumbles. At least eleven pleasure piers were constructed at Welsh seaside resorts between 1840 and 1900. Only those at Aberystwyth, Bangor, Beaumaris, Colwyn Bay, Llandudno, Mumbles and Penarth remain standing today. Those at Rhyl, Tenby and Rhos-on-Sea were lost in 1973, 1953 and 1954 respectively. A former pier at Aberavon is now a breakwater.^[13]

Communications

Historically, many Welsh coastal communities relied upon transport by sea but railways arrived in the middle of the nineteenth century and the road network was steadily improved.

Sea transport