Lagan Weir
Encyclopedia
The Lagan Weir, completed in 1994, at a cost of £14m, is located across the Lagan between the Queen Elizabeth Bridge and the M3 bridge (completed around the same time) in Belfast
, Northern Ireland
. The Lagan Weir was jointly funded by the Corporation and the European Commission
it was constructed by Charles Brand Ltd and designed by Ferguson and McIlveen.
The weir
is a series of massive steel barriers which are raised as the tide retreats to keep the river at an artificially constant level. This improvement to the sewerage system combined with massive dredging of the river by mechanical excavators, and installation of an underwater aeration system, has led to a marked improvement in water quality and the environment around the river. Lagan Weir,dredging and aeration have increased water quality in the river and salmons returning. An otter and seals have followed the fish that now move up river to spawn in what was once an aquatic death trap.
The objective of the structure is to keep the level of the river artificially constant, as it is a tidal river the level of the water varied by up to three metres between high and low tide. This exposed mudflats which were unsightly and emitted a strong odour, particularly in the summer months. The transformation of the riverside by the construction of the weir has been a catalyst for development along the riverside. Another part of the project is the “Lagan Lookout” centre which explains the history and function of the weir as well as the history of the Lagan itself.
Belfast
Belfast is the capital of and largest city in Northern Ireland. By population, it is the 14th biggest city in the United Kingdom and second biggest on the island of Ireland . It is the seat of the devolved government and legislative Northern Ireland Assembly...
, Northern Ireland
Northern Ireland
Northern Ireland is one of the four countries of the United Kingdom. Situated in the north-east of the island of Ireland, it shares a border with the Republic of Ireland to the south and west...
. The Lagan Weir was jointly funded by the Corporation and the European Commission
European Commission
The European Commission is the executive body of the European Union. The body is responsible for proposing legislation, implementing decisions, upholding the Union's treaties and the general day-to-day running of the Union....
it was constructed by Charles Brand Ltd and designed by Ferguson and McIlveen.
The weir
Weir
A weir is a small overflow dam used to alter the flow characteristics of a river or stream. In most cases weirs take the form of a barrier across the river that causes water to pool behind the structure , but allows water to flow over the top...
is a series of massive steel barriers which are raised as the tide retreats to keep the river at an artificially constant level. This improvement to the sewerage system combined with massive dredging of the river by mechanical excavators, and installation of an underwater aeration system, has led to a marked improvement in water quality and the environment around the river. Lagan Weir,dredging and aeration have increased water quality in the river and salmons returning. An otter and seals have followed the fish that now move up river to spawn in what was once an aquatic death trap.
The objective of the structure is to keep the level of the river artificially constant, as it is a tidal river the level of the water varied by up to three metres between high and low tide. This exposed mudflats which were unsightly and emitted a strong odour, particularly in the summer months. The transformation of the riverside by the construction of the weir has been a catalyst for development along the riverside. Another part of the project is the “Lagan Lookout” centre which explains the history and function of the weir as well as the history of the Lagan itself.