Until recently the possibility of salmon and sea trout swimming in the Aire seemed as likely as pigs flying in the sky. It has been almost two centuries since the people of Leeds, Bradford and the surrounding countryside have had the pleasure of observing, or indeed catching, such creatures. But this is about to change.
The Aire Rivers Trust and the Environment Agency now agree that salmon and sea trout, along with eels and brook lamprey, will begin repopulating the Aire within the next five years.
It is the region’s industrial legacy, in the form of a series of more than 20 weirs coupled with poor water quality that has prevented migratory fish from reaching the upper river. During the industrial revolution, the Aire was pumped with waste from factories and urban centres, and as recently as the late 20th century, outdated sewage treatment plants prolonged its water pollution problems.
But now, thanks to better regulation and de-industrialisation, water quality has improved and is no longer a limiting factor for fish. Even in urban centres like Leeds, grayling, a fish which seeks out the cleanest water, have been spotted.
Freshwater trout now breed throughout the Aire catchment area, right up to where the river rises at Malham. Downstream, the Environment Agency has caught sea trout weighing up to 8lbs, and recorded up to 25 salmon an hour at Knottingley weir.
As fish have returned, so have otters and heron. Otters have been caught on CCTV at Granary Wharfe in Leeds city centre and are increasingly common in the upper catchment area.
The return of salmon and sea trout to the upper river is now prevented only by a handful of man-made weirs. Pete Turner, fisheries officer at the Environment Agency, says: “Ten years ago you might have looked at it and had your head in your hands, but actually it’s happening. Structures and passes are being built.
“The River Aire’s my river. It has its issues, but we’re putting in place what we think is the right thing.”
Kevin Sunderland, chairman of the Aire Rivers Trust, is equally passionate about the river’s fisheries. He says the possibilities for salmon and sea trout will change after the biggest remaining challenge, the weir near Knostrop sewage treatment works in South Leeds, has been developed.
At both Knostrop and Crown Point, a smaller weir between Knostrop and Leeds Railway Station, new moving weirs will be built as part of the £50m Leeds Flood Alleviation Scheme. Construction is due to begin this year and is scheduled to be completed next year. It means that if the rains are favourable, salmon and trout will be able to reach West Yorkshire’s great cities.
“Knostrop is the killer,” says Mr Sunderland.
“I’ve seen salmon and trout there trying to get up. It’s the shape of it. It projects out at the bottom, which make it very hard for the fish to climb.”
Beneath Leeds Railway Station itself, the river flows under the Dark Arches, a complex of massive underground channels, roads and walkways belonging to Network Rail, which is working with the Environment Agency to ensure fish can get through.
Mr Sunderland believes minimal intervention will be required. “It might just be a matter of bolting in some boulders to slow the current and give the fish somewhere to rest.”
A couple of miles up the river, the Aire Rivers Trust has been building two fish passes in Kirkstall with support from Leeds City Council and Defra’s Catchment Restoration Fund. Its weir at St Anns is now operational and work is underway at Burley Mills.
Last year the Environment Agency completed a new fish pass at Rodley, between Leeds and Shipley which is owned and maintained by Yorkshire Water. Between 2015 and 2020, Yorkshire Water will be investing £10m on a further 20 barriers to fish passage on Yorkshire rivers and their tributaries.
Neil Trudgill of the Environment Agency says: “The fish bypass at Rodley is an essential step in the recovery of the river’s fish populations.
“The naturalised design will provide a passage around the weir as well as a habitat in which fish and other aquatic life can actually live, feed and grow.”
Further upstream, at Hirst Weir in Shipley, members of Bradford Amateur Rowing Club are working with the Environment Agency to raise money for repairs to the weir. Work on designs for a fish pass, which will be installed as part of the project, is underway.
But although progress has exceeded expectations, there’s still work to do. For example at Chapel Haddlesey, the tidal limit of the Aire, and Armley Mills, next to Leeds Industrial Museum, the building of fish passes has stalled due to interest in hydro energy projects.
The Environment Agency has already produced a design for a fish pass at Armley Mills, but the scheme is on hold while Leeds City Council evaluates the site. There is no completion date for the project yet, and currently no schedule for construction.
However, at Armley, Chapel Haddlesey and elsewhere, developers of hydro projects are obliged to build fish passage into their plans.
Knottingley Weir remains one of the biggest barriers to fish passage on the Aire and Calder river system. Migratory fish are able to ascend the weir when it floods in periods of heavy rainfall, but their progress upstream can be delayed for months in dry summers. A new fish pass has been mooted.
More work on our waterways can be expected. Under the Water Framework Directive, the Government is committed to a self-sustaining population of migratory fish in the Aire and other Yorkshire rivers by 2021.
Kevin Sunderland, chairman of the Aire Rivers Trust, says it is on track to beat that target. “The river’s set to impro ve to a standard which couldn’t have previously been considered possible.”