Fears viaduct work could harm salmon
Anglers are concerned that work at a railway viaduct over the Allan Water south of Dunblane will prevent salmon from ascending the river.
Network Rail have submitted plans to Stirling Council for the repair and protection of the B-listed Old Mill of Keir viaduct involving concrete ‘scour protection’ features to stop the erosion of the river bed.
Safety concerns over the viaduct, during high and fast flowing water in February this year, prompted the temporary closure of the Stirlingperth railway line.
Network Rail’s proposals involve removing the remnants of an old weir which was built to dam water to supply a mill, the excavation of the river bed and its banks, and the installation of concrete ‘anti-scour matresses.’
However, anglers told the Observer this week that the application does not include any engineering measures to help migratory fish like salmon, young eels and lamprey, to swim upstream.
There is also concern that the work, scheduled to take 12 weeks, could be carried out during the main salmon run between August and October.
One angler said: “Clearly Network Rail need to take steps to ensure the future of the viaduct as any further high water levels could cause the bridge’s collapse along with the closure of the railway line.
“However, these plans are tantamount to ecological vandalism.
“The remains of the weir are beneficial to the ecology of the river as it creates pools of water that allow migratory fish species to ascend this area.
“Excavators will re-profile the river bed and banks to make it suitable for the installation of concrete anti-scour mattresses.
“The concrete anti-scour mattresses will be laid down over a distance of 41 metres. They will follow a steady straight gradient downhill with a difference in elevation of around 1.2 metres. They’re effectively creating concrete chutes.
“No mention has been made in the application for any engineering measures to facilitate migratory fish to get upstream. As proposed, the plans will create an impassable barrier.
“During the first few high water events there is the probability that the thin river bedding immediately downstream will be washed clean off the underlying rock strata further compounding the chute effect and making a bigger obstacle that just can’t be overcome by any fish.
“Not only do these fish create sport for anglers – and revenue for the local economy – but the young fish are prey for various bird species like Kingfisher and saw-billed ducks. The adults are prey for otters. The whole river ecosystem would be in danger of collapse if the migratory fish can’t get beyond this point.
“Any work this autumn would disrupt the main salmon run, causing the death of many fish which spawn October to January. And any fish eggs and young emerging fish are vulnerable until the end of May.”
In a statement submitted with the plans Network Rail said: “[We] would like to work collaboratively with Stirling Council to ensure that these urgent works to protect this structure are carried out this year. It is expected that the works themselves will take about 12 weeks and are programmed to commence in early August 2020 to allow them to be completed in the summer months.
“Given these very tight timeframes and the importance of this work to safeguarding this important railway and heritage structure we would appreciate any priority that you can give.
“We would also request ongoing dialogue regarding the wording of any conditions that the planning authority is intending to impose before these are finalised.”
These plans are tantamount to ecological vandalism