Over time, erosion of the banks of the river was causing metal rich sediment from the former Whitesike and Bentyfield mines to enter the burn, causing pollution.
The £380,000 project, delivered over 12 weeks by Tyne Rivers Trust, saw stone that had collapsed into the river, along with imported stone, used to rebuild embankments originally installed by miners in the 1800s. This will reduce sediment containing very high concentrations of metals such as lead, cadmium and zinc from entering the river.
The work is part of the Water and Abandoned Metal Mines (WAMM) programme, led in partnership by the Environment Agency and Coal Authority and funded by Defra.
The erosion of metal contaminated soils into the river has been further reduced by installing leaky dams, drainage pipes and a rock ramp. These work to either slow the flow of water coming off the fells during high rainfall or divert it away from the contaminated waste.
Garrigill Burn, in the North Pennines Area of Outstanding Natural Beauty, is a tributary of the River South Tyne, which runs through the North East to the River Tyne Estuary.
Metal pollution caused by the legacy of mining in this area can be seen for up to 60km along the river, with impacts on water and sediment quality, as well as aquatic life.
Improving water quality
Andy Edwards, Environment Agency North East Metal Mines Lead, said:
Diffuse pollution, where metals are washed out of mine waste into rivers, is one of the major sources of metal pollution in the South Tyne.
This completed work at Garrigill will not only reduce the amount of sediment eroded into the burn and improve the water quality of the river both now and into the future, but by rebuilding the wall we have secured a piece of the mining legacy which played such an important role in history.
The site is a scheduled monument and Site of Special Scientific Interest and the work helps to preserve the nationally important mines as an educational resource and public amenity. It's the first diffuse intervention project to be completed since the government set new targets in January this year to halve the length of rivers polluted by harmful metals from abandoned metal mines by 2038.
Water Minister Rebecca Pow added:
This is an excellent example of collaborative action to clean up our waterways and better protect Cumbria's precious natural resources, just one of the many Defra-funded projects to improve England's water quality.
It's the first major project in the area to be completed since we committed to reducing metal pollution in our ground-breaking Environment Act, where we set targets to halve the length of rivers polluted from abandoned metal mines by 2038.
Protecting the environment
Tyne Rivers Trust Project Manager Martin Colling said:
After months of careful planning, I'm extremely proud to announce the successful completion of works along the Garrigill Burn.
It's a testament to the hard work and commitment of multiple organisations pulling together to mitigate the impacts of heavy metal pollution along our rivers which will help protect our environment for future generations.
Repairs have also been completed to a damaged footpath along the north bank of Garrigill Burn, creating a safe surface for walkers.
All footpaths that were closed during the work to keep workers and the public safe have now reopened and the public are thanked for their patience.
The WAMM Programme tackles water pollution caused by historical metal mining across England.
Metal mines played a major part in Britain's history, but abandoned mines now pollute our rivers, harm aquatic life and have an adverse impact on the economy.
In England, this metal mine pollution affects around 1,500km of rivers - 330km in the North East. The aim of WAMM is to create cleaner rivers for future generations, and encourage more wildlife, tourism and opportunities for industry which rely on clean rivers.
