The Environment Agency and Coal Authority started construction on
Nent Haggs Mine Water Treatment Scheme three years ago to address
the polluting legacy of the industrial revolution.
The River Nent - a tributary of the River South Tyne which
ultimately flows to the River Tyne and then the North Sea - is
the most metal polluted river in northern England with very high
concentrations of cadmium, lead and zinc - which are toxic to
fish and the insects they feed on.
The River Nent only has about half of the fish and river flies
expected in a non-polluted river of that kind, because the levels
of harmful metals can be more than 200 times the safe level set
by the government to protect them.
The effect of metal pollution on water quality and aquatic life
can be seen for 60km along the river system, with the metals
accumulating in the River Tyne estuary sediments in Tyneside.
Haggs adit significant source of pollution
One of the most significant sources of pollution is the Haggs
adit, an abandoned mine water drainage tunnel at Nentsberry.
Around 3 tonnes of zinc alone is discharged by the Haggs adit
into the river each year.
Nent Haggs is a nature-based treatment scheme that will remove
the metals from the mine water before they get into the river.
The polluted water will be captured where the water comes out of
the mine in Nentsberry and pumped to the treatment scheme through
a 2.5km long underground pipeline.
The metals will be removed by passing the polluted water through
the treatment ponds and reed beds at West Foreshield before the
treated water is put back into the River Nent. The ponds contain
a layer of material made of limestone, wood bark and straw in
which natural bacterial reactions capture the cadmium and zinc
that are polluting the river. It’s expected that when the scheme
is fully operational in early 2024, it will remove over 90% of
these metals from the water.
The project also includes a new nature reserve, created in
partnership with the Tyne Rivers Trust and Northumbrian Water
Group, which provides space for wildlife and the local community.
The work is part of the Water and
Abandoned Metal Mines (WAMM) Programme, which tackles water
pollution caused by historical metal mining across England, and
has been funded by the Department for Environment, Food and Rural
Affairs (Defra).
The announcement comes during the lead up to World
Rivers Day on 24 September – which highlights the value of
our rivers and aims to increase public awareness about the
threats they face and what is being done to improve them.
Scheme will make a ‘vital difference’
Dr Hugh Potter, the Environment Agency’s Water and Abandoned
Metal Mine lead, 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 vital difference to the natural environment,
boosting biodiversity right across the South Tyne river and will
bring economic benefits to the North East.
Water Minister said:
I am very pleased to see this major project nearing completion,
which will make a vital difference – both environmentally and
economically – to the communities in the North East and Cumbria.
Through this important programme, we are tackling water pollution
caused by historical metal mining, better protecting the natural
environment, boosting biodiversity, and improving England’s
waterways for generations to come.
Nick Cox, the Programme Manager at The Coal Authority, added:
Following several years of development, the Nent Haggs project
showcases excellent collaborative working with our partners at
the Environment Agency, contractors and local stakeholders.
We are delighted to see that the project is close to completion
as projects like Nent Haggs help us deliver on the new metal mine
targets.
The scheme will protect and enhance the natural environment for
future generations as well as positively contribute to the
government’s Environmental Improvement Plan.
About Metal mines
- The Romans first dug lead out of the North Pennines, but the
peak of metal mining was in the 1800s. Although almost all the
mines had been closed by the early 20th Century, they have now
filled up with rainfall and metal-contaminated groundwater will
continue to pour out of and pollute rivers for many decades to
come unless action is taken.
- Pledges to reduce river pollution from abandoned metal mines
are a key part of the government’s Environmental Improvement Plan
(EIP) – in January this year, it approved a target to halve the
length of rivers polluted by harmful metals from abandoned mines
by 2038.
- 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 and 130km in the North West as well as Yorkshire, the
Midlands and Cornwall.
