Severn Trent raises 'outstanding concerns' over relief road's impact on water quality

The utilities company has written to Shropshire Council to outline its position on authority's proposal for the road – and has made two specific requests.

The letter, from town planning manager, Gareth Smith, set outs Severn Trent's need to protect water supplies for Shrewsbury from boreholes to Severn Trent Waterworks.

The proposal for the North West Relief Road (NWRR), which would complete the ring road around Shrewsbury, would see construction take place through what is called a "groundwater Source Protection Zone" – a zone set by government to safeguard the quality of drinking water.

As a result Severn Trent says it wants assurances to ensure the town's water supplies are not affected – and cannot support the plans without them.

Mr Smith says: "At Shelton Water Treatment Works (WTW), the boreholes and River Severn together provide the principal public water supply to Shrewsbury and a large part of Shropshire. Therefore, we must consider the NWRR development carefully to ensure these supplies are protected.

"Any construction or operational activity associated with the proposed development should not cause any increase in risk to the operation of the WTW assets in the short, medium and long term.

"If there was a need for us to shutdown Shelton WTW due to a water quality issue caused by the construction or operation of the new road and roundabout, that could not be mitigated by the existing water treatment processes, recovery of the supply so that we can continue to provide wholesome water to our customers could be very difficult."

Mr Smith's letter says two things must be resolved before the firm can support the planning application.

The first is a 'turbidity protocol' – a system to measure whether groundwater is contaminated by construction work, and the second is the need for a 'Preventative Maintenance and Emergency Plan' for road drainage – to ensure that water cannot become contaminated through accidents where vehicles spill pollutants or chemicals when travelling on the new road.

Mr Smith said: "The piling work involved poses notable risks to our groundwater abstractions, and we must have absolute clarity now on how the applicant will manage these risks during construction, as we need to be able to continue to supply our customers during this period.

"As we have seen through the recent Phase 4 Ground Investigation, we have confidence that a suitable protocol can be agreed, but this should be provided up front and a planning condition prepared that would require compliance with it.

"Whilst we accept that a planning condition could request a turbidity protocol being put in place before construction commences, we believe this to be a notable issue that should be addressed in advance of determination."

Mr Smith says that Severn Trent wants to work with the council to resolve the issues – but says it must protect water supplies.

He said: "We remain keen to work with you and the applicant to address these issues. We recognise how long this application has been in consideration and appreciate there will be a requirement to determine as quickly as possible.

"However, we must fully understand potential impacts to our supply assets and customers and be confident that appropriate plans and mitigation are in place to deal with identified risks."

The latest issues are another headache for Shropshire Council which has faced significant delays in its attempt to build the NWRR.

Only this week, after months of discussions, the Environment Agency (EA) said it is not currently prepared to support the plans – due to concerns over the potential impact on Shrewsbury’s drinking water.

Those concerns centre on the impact of piling work for foundations for a viaduct at Shelton Rough, as well as the drainage plans for the Holyhead Roundabout.

The council has accepted the response means a further delay in getting the application before a planning committee – but did say it remains hopeful the plan will be considered this summer.