The River Avon, a world-renowned chalk stream teeming with wildlife, is undergoing a transformative restoration thanks to investment from National Highways’ Environment and Wellbeing Fund, topped up by funding from Natural England via the Conservation Enhancement Scheme (CES) and the Species Recovery Programme (SRP). This ambitious project, led by Wessex Rivers Trust, focuses on the stretch between Durrington and Lord’s Walk in Amesbury.
The goal? To rejuvenate this unique ecosystem, benefiting species like Atlantic salmon, water voles, and otters.
A River Shaped By History
The River Avon has been at the heart of Wiltshire’s natural and human history for thousands of years. Flowing through the historic landscape of Amesbury, its waters have long sustained wildlife and communities alike. However, the 20th century saw significant alterations that disrupted its natural processes.
In the 1960s, the expansion of the A303, including the construction of three major road bridges, dramatically altered the river’s course. The Avon was straightened, its riverbed dredged, channels blocked off, and banks cleared, devastating the natural chalk stream and floodplain habitat.
The sluices at Bowles Hatches, a concrete weir at Lord’s Walk, and a syphon channel beneath the main river have created further barriers to fish migration. These modifications reduced biodiversity, disconnected the river from its floodplain, and made life much harder for species like Atlantic salmon that depend on free-flowing water to migrate upstream and spawn.
A Multi-Phase Restoration Effort
To reverse decades of degradation, Wessex Rivers Trust has embarked on an extensive, multi-phase restoration programme. The project began in 2021 with the completion of the design and permitting phase, followed by the first delivery phase upstream of the A303 in Autumn 2023. The second phase, downstream of the A303, was completed in Autumn 2024, with additional tree works and fencing scheduled for Spring and Summer 2025.
Key Achievements So Far:
This restoration project has already delivered significant improvements:
• 400 metres of new chalk stream habitat created by bypassing a major weir, opening up many miles of river upstream to migrating fish.
• 3km of enhanced river channel, reinstating natural features lost to historic modifications.
• Creation of several hectares of wet woodland habitat and improved floodplain connectivity, boosting biodiversity.
Restoring Natural Processes
The restoration has focused on reinstating the natural features that had been lost:
Upstream of the A303:
• Restoring a natural gravel riverbed to reverse historic dredging.
• Introducing large woody habitat features using locally sourced timber.
• “Skylighting” tree works to enhance light conditions, promoting the growth of aquatic plants like Ranunculus.
Downstream between the A303 and Amesbury Road bridges:
• Constructing a new channel to bypass the old weir, adding 400m of pristine chalk stream habitat.
• Infilling the old weir carrier and creating a backwater habitat.
• Decommissioning the syphon channel and transforming the woodland channel into a wet woodland backwater.
A Haven for Salmon
One of the most exciting outcomes of this project is its impact on the River Avon’s Atlantic salmon population. Historically, the weir at Lord’s Walk severely restricted their migration. Surveys indicated that upstream of the weir, trout outnumbered salmon by a 90:10 ratio, whereas downstream the ratio was closer to 50:50. With the barriers removed, salmon now have a much greater chance of successfully reaching their spawning grounds.
Looking Ahead
To fully realise the benefits of this work, further enhancements are planned for 2025:
• Continued upstream tree works to improve light penetration, fostering macrophyte growth—a crucial factor in salmon habitat quality.
• Additional in-stream habitat improvements at Lord’s Walk to aid downstream migration.
