A new fish pass built by the Environment Agency at historic Calver Weir on the River Derwent has been completed at a cost of £165,000. On Friday 5 March 2010 it carried water for the first time offering fish a route up the river beyond the weir. The fish pass is part of a wider project to restore the weir.

Calver Weir Restoration Project (CWRP), a local charitable trust, has been raising money for a number of years to restore the 18th century weir to its former glory and to prevent its collapse.

The total restoration project cost is £1.841 million and it is expected to be completed by August 2010. Defra contributed £165,000 to fund the construction of the fish pass. Heritage Lottery Fund (HLF) awarded £1,279,400 towards the project to restore and interpret the weir and its surrounding wetland. English Heritage awarded the project a further £100,000.

These sources of funding largely underpinned the major works, augmented by other donations from Peak District National Park Authority, local businesses and the community in general.

Calver Weir is a large unique S-shaped Grade II listed structure some 106 metres long situated on the Upper Derwent. It originally provided water to power the cotton mill at Calver which was part of the new industry pioneered by Richard Arkwright. However it also formed a barrier to natural fish migration and has prevented the river achieving a ‘good ecological status’ under the Water Framework Directive (WFD).

Brown trout, a UK Biodiversity Action Plan (BAP) species, grayling and brook lamprey (also a BAP species) are the main species present in these reaches. Without a fish pass these fish could not move upstream of the weir to complete their natural lifecycles.

As well as being necessary to help the river reach ‘good ecological status’ under WFD, the new fish pass helps us meet our objectives to improve the fishery and angling experience on the River Derwent.

Together with other work we are doing to improve habitat it is a move towards sustainable fish populations and may reduce the need for re-stocking in the future.

Environment Agency Fisheries Officer Bryony Devoy says “The new fish pass opened on 5 March and we are hoping that we will soon see the first fish in hundreds of years move up past the weir and colonise new stretches of the River Derwent.

“This is really good news for the river and for the restoration of this historic weir. We now aim to target more of these man-made obstacles on the Derwent, opening up larger stretches of river for more natural colonisation.

“We also hope this first project will set the standard for the fish passes that will be required for future hydropower applications within the Derwent catchment.”