The
Menai Strait is a narrow stretch of shallow tidal water about 25 km (15.5 mi) long, which separates the island of
AngleseyAnglesey , also known by its Welsh name Ynys Môn , is an island and, as Isle of Anglesey, a county off the north west coast of Wales...
from the mainland of
WalesWales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...
.
The strait is bridged in two places - the main A5 road is carried over the strait by
Thomas TelfordThomas Telford FRS, FRSE was a Scottish civil engineer, architect and stonemason, and a noted road, bridge and canal builder.-Early career:...
's elegant iron
suspension bridgeThe Menai Suspension Bridge is a suspension bridge between the island of Anglesey and the mainland of Wales. Designed by Thomas Telford and completed in 1826, it was the first modern suspension bridge in the world.-Construction:...
, the first of its kind, opened in January 1826, and adjacent to this is
Robert StephensonRobert Stephenson FRS was an English civil engineer. He was the only son of George Stephenson, the famed locomotive builder and railway engineer; many of the achievements popularly credited to his father were actually the joint efforts of father and son.-Early life :He was born on the 16th of...
's 1850
Britannia Tubular BridgeBritannia Bridge is a bridge across the Menai Strait between the island of Anglesey and the mainland of Wales. It was originally designed and built by Robert Stephenson as a tubular bridge of wrought iron rectangular box-section spans for carrying rail traffic...
. Originally this carried rail traffic in two wrought-iron rectangular box spans, but after a disastrous fire in 1970, which left only the
limestoneLimestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
pillars remaining, it was rebuilt as a steel
box girder bridgeA box girder bridge is a bridge in which the main beams comprise girders in the shape of a hollow box. The box girder normally comprises either prestressed concrete, structural steel, or a composite of steel and reinforced concrete. The box is typically rectangular or trapezoidal in cross-section...
, and now carries both rail and road traffic. Between the two bridge crossings there is a small island in the middle of the strait, Ynys Gorad Goch, on which are built a house and outbuildings and around which are the significant remains of
fish trapA fish trap is a trap used for fishing. Fish traps may have the form of a fishing weir or a lobster trap. A typical trap might consist of a frame of thick steel wire in the shape of a heart, with chicken wire stretched around it. The mesh wraps around the frame and then tapers into the inside of...
s, no longer used.
The strait varies in width from 400 metres (1,312.3 ft) from Fort Belan to
Abermenai PointAbermenai Point is the southernmost part of the island of Anglesey in Wales.It is the northern point of the western entrance of the Menai Strait.- External links :...
to 1100 metres (3,608.9 ft) from Traeth Gwyllt to Caernarfon Castle. It then narrows to about 500 metres (1,640.4 ft) in the middle reaches (Y Felinheli and Menai Bridge) and then it broadens again. At Bangor Pier it is 900 metres (2,952.8 ft) wide. It then widens out, and the distance from Puffin Island to Penmaenmawr is about 7.5 kilometres (4.7 mi). The differential
tideTides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the moon and the sun and the rotation of the Earth....
s at the two ends of the strait cause very strong currents to flow in both directions through the strait at different times, creating dangerous conditions. One of the most dangerous areas of the strait is known as the
SwelliesThe Swellies is a stretch of the Menai Strait in North Wales. The most popular use of the name is for the stretch between the Britannia Bridge and the Menai Bridge....
(or Swillies –
WelshWelsh is a member of the Brythonic branch of the Celtic languages spoken natively in Wales, by some along the Welsh border in England, and in Y Wladfa...
Pwll Ceris) between the two bridges. Here rocks near the surface cause over-falls and local
whirlpoolA whirlpool is a swirling body of water usually produced by ocean tides. The vast majority of whirlpools are not very powerful. More powerful ones are more properly termed maelstroms. Vortex is the proper term for any whirlpool that has a downdraft...
s, which can be of considerable danger in themselves and cause small boats to founder on the rocks. This was the site of the loss of the training ship
HMS ConwayHMS Conway was a naval training school or "school ship", founded in 1859 and housed for most of its life aboard a 19th-century wooden battleship. The ship was originally stationed on the Mersey near Liverpool, then moved to the Menai Strait during World War II. While being towed back to Birkenhead...
in 1953. Entering the strait at the
CaernarfonCaernarfon is a Royal town, community and port in Gwynedd, Wales, with a population of 9,611. It lies along the A487 road, on the east banks of the Menai Straits, opposite the Isle of Anglesey. The city of Bangor is to the northeast, while Snowdonia fringes Caernarfon to the east and southeast...
end is also hazardous because of the frequently shifting sand banks that make up Caernarfon bar. On the mainland side at this point is
Fort BelanFort Belan is a coastal fortress in North Wales. It is located opposite Abermenai Point, at the south-western end of the Menai Strait, on the coast of Gwynedd, in the parish of Llanwnda...
, an 18th-century defensive fort built in the times of the American War of Independence.
Origins
The present day channel is a result of erosion by successive ice-sheets during the series of
PleistoceneThe Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
glaciations. Ice moved from northeast to southwest across
AngleseyAnglesey , also known by its Welsh name Ynys Môn , is an island and, as Isle of Anglesey, a county off the north west coast of Wales...
and neighbouring
ArfonArfon was one of five districts of Gwynedd, Wales, from 1974 to 1996.It was created by the Local Government Act 1972 on 1 April 1974 from part of the administrative county of Caernarfonshire, namely the municipal boroughs of Bangor and Caernarfon, the Bethesda urban district, the rural districts...
scouring the bedrock, the grain of which also runs in this direction. The result was a series of linear bedrock hollows across the region, the deepest of which was flooded by the sea as world ocean levels rose at the end of the last ice age.
Tidal effects
The tidal effects observed along the banks of the strait can also be confusing. A rising tide approaches from the south-west causes the water in the strait to flow north-eastwards as the level rises. The tide also flows around Anglesey until, after a few hours, it starts to flow into the strait in a south-westerly direction from
Beaumaris. By the time this happens the tidal flow from the Caernarfon end is weakening and the tide continues to rise in height but the direction of tidal flow is reversed. A similar sequence is seen in reverse on a falling tide. This means that slack water between the bridges tends to occur approximately one hour before high tide or low tide.
Theoretically it is possible to ford the strait in the Swellies at low water, spring tides when the depth may fall to less than 0.5 metres (1.6 ft). However, at these times a strong current of around 9 kilometres per hour (5.6 mph) is running, making the passage extremely difficult. Elsewhere in the strait the minimum depth is never less than 2 metres (6.6 ft) until the great sand flats at Lavan sands are reached beyond
BangorBangor is a city in Gwynedd, north west Wales, and one of the smallest cities in Britain. It is a university city with a population of 13,725 at the 2001 census, not including around 10,000 students at Bangor University. Including nearby Menai Bridge on Anglesey, which does not however form part of...
.
Ecology
Marine
Because the strait has such unusual tidal conditions, coupled with very low wave heights because of its sheltered position, it presents a unique and diverse benthic ecology.
The depth of the channel reaches 15m in places, and the current can exceed 7 knots. It is very rich in sponges.
The existence of this unique ecology was a major factor in the establishment of the School of Ocean Sciences at
Menai BridgeMenai Bridge is a small town and community on the Isle of Anglesey in north Wales. It overlooks the Menai Strait and lies by the Menai Suspension Bridge, built in 1826 by Thomas Telford...
, part of the University of Wales, Bangor as well as its status as a
special area of conservation with marine components. The waters are also a proposed
Marine Nature ReserveMarine Nature Reserve is a British conservation designation officially awarded by the government to a marine reserve of national significance....
.
Land
The same unique ecology and geomorphology has let to a number of designations of
SSSIsA Site of Special Scientific Interest is a conservation designation denoting a protected area in the United Kingdom. SSSIs are the basic building block of site-based nature conservation legislation and most other legal nature/geological conservation designations in Great Britain are based upon...
along the strait including Glannau Porthaethwy, the
ivyIvy, plural ivies is a genus of 12–15 species of evergreen climbing or ground-creeping woody plants in the family Araliaceae, native to western, central and southern Europe, Macaronesia, northwestern Africa and across central-southern Asia east to Japan and Taiwan.-Description:On level ground they...
-
oakAn oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
- ash woodland on the southern shore (Coedydd Afon Menai) and Lavan Sands (Traeth Lafan).
Much of the land on Anglesey at the eastern end of the strait is designated as an area of outstanding natural beauty.
Places on the Strait
- Beaumaris
- Bangor
Bangor is a city in Gwynedd, north west Wales, and one of the smallest cities in Britain. It is a university city with a population of 13,725 at the 2001 census, not including around 10,000 students at Bangor University. Including nearby Menai Bridge on Anglesey, which does not however form part of...
- Caernarfon
Caernarfon is a Royal town, community and port in Gwynedd, Wales, with a population of 9,611. It lies along the A487 road, on the east banks of the Menai Straits, opposite the Isle of Anglesey. The city of Bangor is to the northeast, while Snowdonia fringes Caernarfon to the east and southeast...
- Menai Bridge
Menai Bridge is a small town and community on the Isle of Anglesey in north Wales. It overlooks the Menai Strait and lies by the Menai Suspension Bridge, built in 1826 by Thomas Telford...
- Y Felinheli
Y Felinheli is a village lying beside the Menai Strait between Bangor and Caernarfon in Gwynedd, north-west Wales. The population is about 2,200.-Etymology:...
(formerly Port Dinorwic in English)
Just north of the rail bridge on Anglesey is the famously named Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch.
History
According to
HeimskringlaHeimskringla is the best known of the Old Norse kings' sagas. It was written in Old Norse in Iceland by the poet and historian Snorri Sturluson ca. 1230...
, the 11th Century
Norse-GaelThe Norse–Gaels were a people who dominated much of the Irish Sea region, including the Isle of Man, and western Scotland for a part of the Middle Ages; they were of Gaelic and Scandinavian origin and as a whole exhibited a great deal of Gaelic and Norse cultural syncretism...
ruler
Echmarcach mac RagnaillEchmarcach mac Ragnaill was the Gall-Gaidhel King of the Isles, Dublin , and much of Galloway. According to Seán Duffy he was either a grandson or great-grandson of Ivar of Waterford, but an alternative exists. Benjamin Hudson has contended Echmarcach was a grandson of Gofraid mac Arailt...
plundered in
WalesWales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...
with his friend, the
vikingThe term Viking is customarily used to refer to the Norse explorers, warriors, merchants, and pirates who raided, traded, explored and settled in wide areas of Europe, Asia and the North Atlantic islands from the late 8th to the mid-11th century.These Norsemen used their famed longships to...
Guttorm Gunnhildsson. However they started quarreling over the plunder and fought a battle at Menai Strait. Guttorm won the battle by praying to Saint Olaf and Echmarcach was killed.
In the 12th Century, a later Viking raid and battle in the Menai Strait are recounted in the
Orkneyinga SagaThe Orkneyinga saga is a historical narrative of the history of the Orkney Islands, from their capture by the Norwegian king in the ninth century onwards until about 1200...
as playing an important role in the life of
Magnus Erlendsson, Earl of OrkneySaint Magnus, Earl Magnus Erlendsson of Orkney, sometimes known as Magnus the Martyr, was the first Earl of Orkney to bear that name, and ruled from 1108 to about 1115...
- the future Saint Magnus. He had a reputation for piety and gentleness, and refusing to fight in the raid on
AngleseyAnglesey , also known by its Welsh name Ynys Môn , is an island and, as Isle of Anglesey, a county off the north west coast of Wales...
stayed on board his ship, singing psalms.
This incident is recounted at length in the 1973 novel
MagnusMagnus is a novel by the Orcadian author George Mackay Brown. His second novel, it was published in 1973. it is a fictional account of the life and execution of the twelfth century Saint, Magnus Erlendsson, Earl of Orkney.-Plot introduction:...
by Orcadian author
George Mackay BrownGeorge Mackay Brown , was a Scottish poet, author and dramatist, whose work has a distinctly Orcadian character...
, and in the
1977
operaOpera is an art form in which singers and musicians perform a dramatic work combining text and musical score, usually in a theatrical setting. Opera incorporates many of the elements of spoken theatre, such as acting, scenery, and costumes and sometimes includes dance...
,
The Martyrdom of St MagnusThe Martyrdom of St Magnus is a chamber opera in one act by the British composer Peter Maxwell Davies. The libretto, by Davies himself, is based on the novel Magnus by George Mackay Brown. The opera was first performed in St...
by
Peter Maxwell DaviesSir Peter Maxwell Davies, CBE is an English composer and conductor and is currently Master of the Queen's Music.-Biography:...
. The first of the opera's nine parts is called "The Battle of Menai Strait".
External links