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The charity making life better by water

Welsh Harp Brent Reservoir re-fill to begin by mid-April

We're aiming to complete its works at the Welsh Harp Brent Reservoir by the middle of April, and then allow it to re-fill with water.

Group of people with litter pickers facing towards camera.

The Welsh Harp Brent Reservoir was built in 1835 to supply water to the Grand Union Canal. As well as being a place for sailing, watersports and walking, the reservoir is protected as a Site of Special Scientific Interest (SSSI) for the rich diversity of wildlife found on site, including water birds and 16 protected plant species.

The reservoir works underway are required under the Reservoir Act 1975 and are supported by players of People’s Postcode Lottery. The works include: replacing the chains that operate the reservoir’s sluice gates and control the water levels in the reservoir; and repainting the Valve House Tower from where the gates are operated. To undertake these works, we first had to drain the reservoir and rescue the fish.

What's been happening?

Ros Daniels, our London & South East director, explains: “The Welsh Harp Brent Reservoir is one of London’s most significant urban wild spaces and provides a much valued area of green open space for people and wildlife.

“To carry out our essential maintenance works at the reservoir, we’ve had to drain around 1,000 mega litres of water, enough to fill 400 Olympic-sized swimming pools. We’ve rescued around 100,000 fish and our volunteers and contractors have removed over 1,000 bags rubbish, as well as dustbins, tyres, e-bikes, scooters, safes, clothing and suitcases.

“Over the winter months, we’ve also been carrying out a series of environmental improvements at the Welsh Harp, including creating new nesting areas in the reed beds for wetland birds, willow coppicing and removing silt from one of the ponds. Once the reservoir has refilled with water, with the support of the Welsh Harp Conservation Group, we plan to install 13 new island habitats for common terns, one of the species of water bird that lives on the reservoir.”

“Unfortunately the succession of winter storms and high rainfall levels we’ve experience over the winter have caused us significant delay. We’ve worked closely with Natural England to develop a plan to minimise the impact of this delay on the nesting birds that rely on the reservoir. We’ve installed visual bird scarers, including holographic tape and decoy birds of prey, to discourage birds from nesting until the reservoir has refilled. We expect this to happen by the end of May, but it depends on how much rain we get.”

A slice of countryside and serenity

Laura Chow, head of charities at People’s Postcode Lottery, said: “The teams involved in the Welsh Harp Brent Reservoir project have put in a mammoth effort draining it, rescuing wildlife and removing the tonnes of litter.

“Welsh Harp Brent Reservoir is a little slice of countryside and serenity in the city, so I’m delighted the next stage of works in allowing it to be refilled is underway and money raised by our players is helping to make this possible.”

The reservoir remains open to the public throughout the works, but signs are in place warning visitors not to walk on the reservoir’s drained area and mud for their own safety.

For more information about the People’s Postcode Lottery go to

Thanks for your support

Thanks to our incredible Crowdfunder supporters, volunteers, and partners, we've achieved something truly remarkable. Together, we've so far raised over £15,000 to fund essential repairs and maintenance, ensuring the safety and accessibility of this cherished green space.

Last Edited: 24 April 2024

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