Menai Strait

• 1. Glacial Erosion And Fault Systems

  ›

  The Menai Strait formed during the Pleistocene epoch when ice sheets moved from northeast to southwest across Anglesey and neighbouring Gwynedd. These massive glaciers scoured the underlying bedrock along a line of weakness known as the Menai Strait fault system. The grain of the rock ran in the same direction as the movement of the ice, creating deep linear hollows. As world ocean levels rose at the end of the last ice age around 10,000 BC, these hollows flooded to become the present day channel. This geological process shaped the strait into its current form over thousands of years before human history began.

  2

• 2. Viking Raids And Medieval Battles

  ›

  According to Heimskringla, the 11th century Norse-Gael ruler Echmarcach mac Ragnaill plundered in Wales with his friend, the Viking Guttorm Gunnhildsson. They started quarreling over the plunder and fought a battle at the 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 Saga as playing an important role in the life of Magnus Erlendsson, Earl of Orkney. He had a reputation for piety and gentleness. Refusing to fight in the raid on Anglesey, he stayed on board his ship, singing psalms. This incident is recounted at length in the 1973 novel Magnus by Orcadian author George Mackay Brown, and in the 1977 opera, The Martyrdom of St Magnus by Peter Maxwell Davies.

• 3. Tidal Currents And Swellies Hazards

  ›

  The differential tides at the two ends of the strait cause very strong currents which create dangerous conditions. One of the most hazardous areas is the Swellies between the two bridges where rocks near the surface cause over-falls and local whirlpools. This was the site of the loss of the training ship HMS Conway in 1953. Entering the strait at the Caernarfon end is also hazardous because of the frequently shifting sand banks that make up Caernarfon bar. A rising tide approaches from the south-west causing 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 this time 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.

  56

• 4. Sponge Diversity And Marine Ecology

  ›

  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 40 metres in places and the current can exceed 2 knots. It is very rich in sponges. The existence of this unique ecology was a major factor in the establishment of Bangor University's School of Ocean Sciences at Menai Bridge. The waters are also a proposed Marine Nature Reserve. Eight of the numerous Menai Strait fish weirs are now scheduled monuments. Aberlleiniog/Trecastell serve as key historic landscape features and processes according to Gwynedd Archaeological Trust. The banks of the Menai Strait are home to the critically endangered Menai Whitebeam. The plant is an extremely rare species of Sorbus only found in this part of North Wales. The population contains about 30 plants and most of these are thought to be mature.

  47

• 5. Suspension And Tubular Bridge Designs

  ›

  Opened in 1826, the Menai Bridge is a suspension bridge designed by Thomas Telford. It carries the A5 road which connects London to Holyhead on Holy Island. The bridge itself is grade one listed and a candidate to become a UNESCO World Heritage Site. Opened in 1850, the Britannia Bridge was built as a rail bridge connecting Anglesey to the mainland. The bridge is 461 metres long and 40 metres tall carrying the North Wales Coast Line connecting Holyhead to Crewe. Between 1970 and 1972 the bridge underwent a redesign in order to accommodate what would later become the A55 dual carriageway connecting Chester to Holyhead. The bridge is grade two listed and the more common crossing point out of the two bridges. It is an adaptation of a tubular railway bridge completed in 1850 to a design by Robert Stephenson which was severely damaged by a fire in 1970.

  910

• 6. Third Crossing Proposal And Environmental Decision

  ›

  Since 2007 a Third Menai Crossing had been proposed by government to tackle congestion on the other two crossings. However on the 14th of February 2023 the Welsh Government announced that the project would not go ahead citing efforts to reduce car usage its environmental impact and it being a blot on the landscape. Issues with financing the project was later stated by the government as another reason why the project could not proceed. Lee Waters deputy minister for climate change later stated the crossing could be considered again as part of a wider review into the infrastructure of North Wales rather than individually. Now every year for two weeks in the summer the MV Balmoral undertakes a similar service to the pleasure steamers of the Liverpool and North Wales Steamship Company which operated from the 1890s until 1963. After the company's voluntary liquidation in 1962 P and A Campbell took over the services for a while.

  1112131415