Redundant weir removal

Posted by Rod Ellison on 23/03/2011

Redundant weir removal

As reported on the Environment Agency website, two important barriers to fish have been removed by the Environment Agency’s Fisheries Team on the Meden and Maun rivers, near to New Ollerton, Nottinghamshire. Both of the weirs were built to measure the flow of water in the 1960s, but became redundant in 1989, and have been unused ever since.

We also note that in Wales, on the Lwyd, a lower Usk tributary,  weirs at Tynantddu and Cwmafon have recently been removed allowing salmon and sea trout into the upper tributaries and head waters which have not seen a migratory fish for 100 years.

And why is it important to remove weirs (that are not in use), as they can form a barrier restricting fish movements on a river. This can be a substantial problem during the spawning season, as it may prevent migratory species such as the European eel from returning to the rivers from the ocean. Of course, there are other benefits – for example redundant weirs can prevent sediment and other nutrients from passing through a river therefore reducing the quality of water in certain areas. 

The recent weir removal project was undertaken to fulfil the objectives of the Humber Eel Management Plan and the European Union Eel (England and Wales) Regulations 2009, by allowing for improved migration passage for eels and elvers. This first phase will enable fish to navigate the 8km of the River Meden, from River Idle in West Drayton, upstream as far as  Perlethorpe. There are also further plans to remove two more barriers during 2011, addressing the upstream navigational problems of Perlethorpe. Kathy Hughes - Fisheries Officer said “Our rivers are the healthiest for 20 years, but we need to do even more to meet stringent new EU standards. Neither the River Maun nor the River Meden have reached Good Ecological Potential under the Water Framework Directive. 

“Fish populations are one of the key reasons for this because there is a lack of good fish habitat due to physical modification of the river and barriers preventing fish migration. 

“The work we have done directly addresses these issues. Alongside other Environment Agency work it will help these rivers achieve Good Ecological Potential in the future and I would especially like to thank the local landowners whose support has made this project possible.”