Railway tunnel surveyed near Whitehaven's discoloured harbour

This photo taken of water in the harbour in February shows the colour change

Technical surveys at a railway tunnel will form part of the investigation into a harbour's discoloured water.

Rust-coloured water started entering Whitehaven Harbour from a culvert in Queens Dock at the end of last year.

Groundwater conditions will be tested in the land above a railway tunnel on the Cumbrian Coast line.

Although the tunnel is not the source of the water, it is hoped more knowledge could prevent polluted water reaching the harbour.

The work to examine the ground about the railway tunnel has been described as "complex"

Network Rail will commission a hydrogeological survey of the tunnel and its immediate surrounding area.

A spokesperson for the company said: "Our teams are continuing to help investigate the exact source of the water discolouration in Whitehaven harbour.

"This involves ongoing technical surveys of groundwater conditions in the land above a railway tunnel which takes the Cumbrian Coast line under the town.

"When these tests are complete, we will share the information with the council and other agencies to help get to the bottom of where the discoloured water is coming from."

It will see an independent specialist carry out surveys to build up a 3D picture of how the area's topography, infrastructure, historic mining features and geology interact with both surface and groundwater in the area.

John Baker, from Whitehaven Harbour Commissioners, said: "It's not straightforward but hopefully we can then look at a solution to then stop the discoloured water entering Bransty Beck and then into the harbour."

Mr Baker added that once the discoloured water was either diverted or prevented from entering the harbour it would only take "a couple of weeks, depending on weather conditions" for the colour of the water to return to normal.

Polluted water from a yet unidentified source is entering the harbour from a culvert

Network Rail is one of a number of organisations which also include the Environment Agency, Coal Authority and Copeland Borough Council who have been working with Whitehaven Harbour Commissioners to find out the source of the the discoloured water.

Initial results from the Environment Agency, which took samples from Queens Dock in December 2022 and February 2023, showed "increased metals in the water".

Network Rail said it hoped the latest survey results could be ready within three months.