Weirs to be removed from River Irwell to help wildlife
8:00am Saturday 5th July 2014 in News
WATER is set to flow freely once more through the River Irwell as work gets underway to transform it to its pre-industrial glory and once again become a haven for wildlife and recreation.
Weirs are being removed from the Bolton stretch of the river as the country’s biggest river restoration project moves into the borough.
Industrial barriers, which are said to be “severely constraining the river’s natural processes”, will be dug out.
The Environment Agency scheme is already making a striking difference to the area, attracting wildlife and people back to its shores.
The River Irwell lost its clean and healthy status — it was home to prized salmon and provided drinking water — when it became central to the industrial revolution.
As a result it became one of the most heavily modified rivers in England.
In recent years, improvements have been made to water quality and the river is now home to fish and other aquatic life.
Brown trout have been and otters have returned after an absence of 150 years.
And the removal of weirs — “barriers” to the river corridor — is said to be key to the recovery of the river, which just 30 years ago carried the unenviable reputation of being classified as one of the most polluted rivers in Europe.
The weir at Prestolee is gone, and plans are now being drawn up to remove it from the corridor flowing through Moses Gate Country Park in the coming weeks.
The Moses Gate project is the biggest undertaken yet, with the weir measuring 2.5 metres by 40 metres.
The weir removal programme, which has also seen the end of the Goshan weir on the River Roch in Bury, has helped create a range of habitats for a wide variety of flora and fauna, and there have been a increase in bird species, such as dippers.
Oliver Southgate, project manager, said work needed to be undertaken as the weirs were in danger of collapsing and their existence prevented habitats from being created.
He added: “The River Irwell was identified as one of the rivers creating most concern in the country.
“The removal of the weirs benefit fish as they can move up the river. The weirs were blocking migration and this programme takes the river back to before the weirs, which are man made were created.
“Their removal creates a good natural ripple which creates a good habitat.
“The fish population is increasing with a Brown Trout spawning habitat and there are signs the otter.”
Recently a 12lb Brown Trout was found in the river, which is fast losing its image of being dirty.
Mr Southgate, who said work was done in consultation with local communities, added: “There are some who like weirs, saying they are part of the heritage, but they are not listed and and if we can, we try to reuse the stone and do something with it, if possible.
“Removal of weirs can prevent flooding.”
The weirs cost on average £15,000 to remove and the work is being carried out by the Environment Agency and organisations The Environment Agency is working alongside The Irwells Rivers Trust, Salford, Association of Rivers Trust, Salford Friendly Anglers and local authorities.
The effort’s to restore the River Irwell has been recognised by the European river restoration centre that have used the Irwell as a successful case study to show others across the whole of Europe about effective river restoration methods.
Mr Southgate added the work would restore the river to what it was like 200 years ago.
Normally just one weir a year is removed, but the Environment Agency in partnership, has removed 12 in a year.
Mr Southgate said: “The River Irwell flows through six major towns and Bolton is key part of the project, and we are doing similar work in those towns do.
“We have had people from China and Malaysia visiting, and the River Irwell Project made the front page of the Malaysian Sun.”