Cardiff Bay Barrage

Cardiff Bay Barrage (Welsh: Morglawdd Bae Caerdydd) lies across the mouth of Cardiff Bay, Wales between Queen Alexandra Dock and Penarth Head. It was one of the largest civil engineering projects in Europe during construction in the 1990s.

The origin of the scheme dates back to a visit by Nicholas Edwards, the Secretary of State for Wales, to the largely-derelict Cardiff docklands in the early 1980s. An avid opera enthusiast, Edwards envisaged a scheme to revitalise the area incorporating new homes, shops, restaurants and, as a centrepiece, an opera house at the waterside. However the tidal nature of Cardiff Bay, exposing extensive mudflats save for two hours either side of high water, was seen as aesthetically unappealing. Edwards credited the solution to this perceived problem to a Welsh Office civil servant, Freddie Watson. Watson proposed building a barrage stretching across the mouth of Cardiff Bay from Cardiff Docks to Penarth, which would impound freshwater from the rivers Ely and Taff to create a large freshwater lake, thus providing permanent high water. By making the area more appealing, investment was to be attracted to the docklands. The development was also inspired by the redevelopment of Baltimore Inner Harbor in the US, where a largely derelict port area was transformed into a thriving commercial district and tourist attraction. The barrage was consequently seen as central to the regeneration project. In 1987, prior to approval of the construction of the barrage, the Cardiff Bay Development Corporation was established to proceed with redeveloping the docklands.

In November 1999, the barrage was completed, with the sluice gates closed at high water, to retain the seawater from the Bristol Channel within the 500 acre (200 hectare) bay.

Oxygenation systems (based on those used at the Swansea Barrage) were installed which improved water quality and allowed the composition of the bay to become entirely freshwater, the only saltwater ingress being that from the three locks providing access to and from the Severn estuary for the proliferating number of boats using Cardiff Bay. This salt water sinks to the bottom of the bay which is then sucked back out to sea via a drainage basin connected to a salt water shaft. The barrage was opened to the public in 2001.

The barrage scheme was opposed by environmentalists and, according to a BBC investigation, by the Prime Minister Margaret Thatcher. Treasury officials had queried the economic case for the development and the economic methodology used to justify it. In 1990, a select committee, which had been unable to examine all economic details it wanted, voted 3–1 in favour of the scheme. Subsequently, BBC Wales discovered that Thatcher wanted to scrap the barrage proposal until Edwards threatened to resign. Opposition to the project also came from many other quarters. One of the most prominent critics was the then Cardiff West Member of Parliament (MP), Rhodri Morgan (Labour), who was later to become First Minister of the Welsh Assembly. Morgan, like Thatcher, said that the scheme would cost too much money. It was reported by the Daily Mirror in March 2000 that the costs of the barrage construction alone had risen to £400 million, and there would be additional £12 million a year charge for maintenance and operation. Morgan said, "This is far higher than was ever identified to Parliament during the passage of the Barrage Bill". In the meantime, local residents living near the edge of the bay and the banks of River Taff feared that their homes would be damaged by the permanently raised water level, as they had been in several previous floods. Environmental groups strongly opposed construction because the bay was an important feeding ground for birds, which would be lost followi

Dam data from Wikidata (CC0) plus curated additions. Summary from Wikipedia (CC BY-SA).