CONSTRUCTION work has started on a £6 million water treatment scheme to clean-up the second most metal polluted river in the country.

The River Nent, which joins the River South Tyne at Alston, has high concentrations of cadmium, lead and zinc, as a result of historic mining in the area.

Now the Nent Haggs Mine water treatment scheme, orchestrated by the Environment Agency and the Coal Authority, will improve water quality, and protect fish and insects.

The knock-on effect will be huge, with cleaner water safeguarding aquatic life along the whole of the River South Tyne.

The scheme will address one of the most significant sources of pollution - an abandoned mine water drainage tunnel at Nentsberry Haggs Mine, in Alston Moor, where around three tonnes of zinc alone is discharged into the river each year.

The mine water will be pumped into the treatment site through a 2.5km long underground pipeline. Metals will be removed by passing the mine water through three treatment ponds and a new wetland at West Foreshield, before returning to the river.

The project is expected to take around two years to construct. The first phase, between July and December, will see the construction of a pumping station, and the installation of the pipeline. The pumps will be housed in a new stone barn near Nentsberry, while associated improvements to surface water drains will help solve some road flooding issues in the area of the A689 road.

The Environment Agency’s Rachael Caldwell said: “This project will have an immediate impact on water quality in the rivers Nent and South Tyne and in future, will help improve sediment quality in the Tyne estuary.

“It will make a huge difference to the natural environment.”