Unlocking the Severn

We’re working on an exciting conservation and engagement project to open up Britain’s longest river, for both the rare fish that depend on it and communities who live alongside it.

Upper Lode Lock on the River Severn Upper Lode Lock on the River Severn

Hundreds of thousands of twaite shad used to migrate up the River Severn each year to reach their natural spawning grounds. But weirs installed in the mid-19th century blocked the shad’s route and the population on the Severn crashed. Today they are one of the UK’s rarest fish.

Shad don’t have the ability to leap over obstacles in the river, unlike salmon, which have adapted to swim past boulders and waterfalls as they travel upstream to spawn. Whilst shad can swim through fast-flowing water, they avoid turbulent patches and are disorientated by complex flows.

The solution

Our ‘Unlocking the Severn’ project will create fish passes at six barriers on the Severn and its River Teme tributary. Fish passes provide fish with a route around an obstacle on the river, such as a weir. One example is a ‘deep vertical slot fish pass’. This is a series of ascending pools running along the bank next to the weir. It allows the shad to swim up above the weir in small, manageable steps.

In total the work will restore 158 miles of river habitat. As well as helping the shad, this will allow free passage for other important and endangered migratory fish species, such as salmon and eel. Having more fish eggs and very young fish (fry) in these higher areas of the river - including shad spawning for the first time in 170 years - will also provide more food for insects. More insects and young fish on the river provide food for other animals and birds. This positive effect cascades through the food web and benefits all the wildlife in the river’s ecosystem.  

A shad being checked and tagged A shad being checked and tagged

Above water

In bringing life back into the upper reaches of the river, we also want to deepen local people’s connection with the Severn. We believe that the river can enrich lives and provide a unique environment to boost wellbeing. We want to give local people, of all ages and backgrounds, inspiring experiences and new insights into the natural world and our relationship with it.

The fish pass we’re building at Diglis, near the centre of Worcester, will be the biggest deep vertical slot fish pass in England and Wales. Most exciting of all, it will include a unique underwater viewing window. We’re hoping this fascinating perspective of the wildlife living in the river will inform and inspire scientists and visitors for years to come.

Thinking about the future is just as important as the structural work we’re doing today. That’s why our heritage and science programme aims to reconnect millions of people with the river, helping them to learn, develop skills and get creative. We plan to involve community groups and more than 6,000 schoolchildren.

Volunteers are already getting involved in events and activities as part of the project, and there are plenty of ways to join in. From green teams creating wildlife habitats to citizen scientists helping us gather important information about shad. There are arts opportunities too, with educators bringing people together to share and celebrate stories about the river. We want as many people as possible to be inspired by the Severn and to continue the legacy of caring for it.

Our partners

This is an ambitious conservation project on the UK’s longest river. We will reconnect a huge tract of important river habitat for wildlife. We are also proactively sharing our knowledge, insights and best practice internationally to benefit other projects in Europe and across the world.

We’re working in partnership with the Severn Rivers Trust, the Environment Agency and Natural England. Funding is being provided by the National Lottery Heritage Fund and the European Union LIFE Nature Programme, as well as The Waterloo Foundation and the partner organisations.

Fish pass works at Diglis weir, River Severn

Our role

As the lead organisation in this project, we’ll be building four of the six fish passes. They will be at weirs at Diglis (pictured), Bevere, Holt and Lincomb. Each fish pass will take approximately 10-12 months to build, and overall the project is planned to be finished in late 2021.

This state-of-the-art engineering will allow shad and other species to swim easily upstream, while at the same time maintaining the impressive weir structures that are essential to maintain river flow and keep the water at the right level for boats. Three of the fish passes are deep vertical slot designs, and at Bevere there will be a bypass channel in the form of a rock ramp. This design is intended to imitate a natural feature of rivers, where the water will split off and run over stones before rejoining the main course.

We’re also responsible for leading and co-ordinating the wide-reaching community engagement plan. Our staff will deliver the following key elements:

  • converting redundant Grade II workshops at Diglis Island into an inspiring learning space for schoolchildren and other visitors
  • an exciting range of events and exhibitions to encourage people of all ages, interests and backgrounds to be inspired by and learn from the Severn
  • creating communications, including the project website, to raise awareness of the project nationally and internationally
  • River Trainee apprenticeships
Unlocking the Severn project partner logos Unlocking the Severn project partner logos

Last date edited: 8 April 2020