A38 weir scheme helps fish migration in Devon


26 Oct 2022

A National Highways funded scheme to help fish navigate the River Ashburn in Devon has been completed in time for the autumn migration season.

A38 weir scheme helps fish migration in Devon

The construction of a new fish pass is helping to support the ecosystem on the River Ashburn by assisting the migration of salmon, eels and other species through Ashburn Check Weirs within the Dartmoor National Park.

An issue was identified by Westcountry Rivers Trust and the Environment Agency which showed that fish were unable to move upstream due to the four historic stepped weirs close to the A38 eastbound entry slip road at Buckfastleigh. Using our Environment and Wellbeing Fund, we were able to fund a £450,000 scheme to adapt the weirs to enable fish to navigate their way upstream to their traditional spawning grounds.

Work started in early June and the scheme, designed by Kier, was delivered by idverde UK, in conjunction with the Westcountry Rivers Trust, Castleford Engineering and Fishtek Consulting.

The work involved cutting the teeth off three of the original four weirs, and baffles were used to create the optimal slope gradient for fish passage, while notches were cut into the top weir crests to maintain fish passage in low flows.

The area sits within the National Park, and is in an environmentally significant location, so this was considered during the construction work. The verges around the A38 eastbound entry slip road at Dart Bridge contain species rich grassland of county-wide importance, and are also home to rare orchids, so our workforce needed to work carefully in the area. As the location also sits within a bat conservation area, no overnight work took place to avoid disturbing bat activity.

Our Environmental Advisor Ben Hewlett said:

“Our work goes beyond operating, maintaining and improving roads, and through our Environment and Wellbeing Fund, we're investing in the environment and communities surrounding our network. We’re delighted we could support such a worthwhile project which will help to support aquatic biodiversity close to the A38 – a glowing example of how this funding and partnership working can make life better for communities, wildlife and the environment around our roads."

Olivia Cresswell, Aquatic Services Manager at Westcountry Rivers Trust, said:

“We are excited these four fish and eel passes, located at the entrance to the River Ashburn, have been created. Fish survey records from the Environment Agency suggest that salmon have been restricted from most of this river since 1999, making this a much-needed construction to improve access to important salmon, trout and eel habitat. We were able to provide fisheries expertise and support during the work, and it really has been a great team effort.”

Ashburn weir fish pass under construction
The fish pass under construction
The completed fish pass, including eel slope on the right
The newly completed fish pass , including a special slope for eels to the right

Last year we also assisted Westcountry Rivers Trust to install a specially designed fish pass on the River Lemon under the A38 dual carriageway near Newton Abbot thanks to our Designated Funding programme.

Elsewhere in the South West our funding has helped enable Cornwall Wildlife Trust to deliver environmental enhancements to the Cornish landscape bordering the A30. A £785,000 investment from our Environment and Wellbeing Fund has also helped to restore and recreate 16.8 hectares of woodland, orchard, grassland and heathland around Ladock to Gwills and Benhaven to Lambourne Mill, north of Truro.

We manage four designated funds, allocated by the Government, to deliver benefits above and beyond building, maintaining and operating England’s strategic roads. Currently in its third year, the funding programme, which was allocated £936m for Roads Period 2 (2020-2025), is divided into four funding streams aimed at making the biggest difference and delivering lasting benefits; Environment and wellbeing, Users and communities, Safety and congestion and Innovation and modernisation.

From protecting the environment and enhancing the landscape around roads, to improving safety, reducing congestion, and supporting communities, the aim is to make a positive difference to people’s lives.

As part of our national biodiversity effort, we've invested nearly £6 million from our Environment and Wellbeing Fund into the country’s Wildlife Trusts’ Network for Nature programme. The funding will enable the Trusts to deliver a total of 26 biodiversity projects to enhance, restore and create more than 1,700 acres (690 hectares) of woodlands, grasslands, peatlands and wetlands across every region of England.

Find out more about our Designated Funds programme