Yorkshire Water’s project to build a new sewer under the A65 in Ilkley to reduce the frequency and duration of discharges from storm overflows into the river Wharfe is set to be extended.

Yorkshire Water has submitted plans to Ofwat and DEFRA to bring forward investment from its 2025-2030 business plans to complete the additional work, which would be required as part of the government’s Storm Overflows Discharge Reduction Plan.

A new section of tunnel, 191 metres in length and 1500mm diameter, will now be bored under the ground between Wharfe View Car park where the existing tunnel project finishes and the riverbank off Castle Road.

A new reception shaft will need to be constructed just above the riverside footpath to enable the work to be carried out, with work beginning on 3 July.

Enabling works will be carried out at the same time as the existing sewer project to try to reduce disruption in the future. The extension of the project will ultimately lead to Rivadale combined sewer overflow being bypassed before March 2026. This will prevent discharges at this point and improve bathing water quality at Ilkley.

Ben Roche, director of wastewater at Yorkshire Water, said: “We’ve asked to bring forward investment and work that would be carried out after 2025 to enable the extension of this scheme while we already have the equipment in place in the area. While this will extend the timescale of the current scheme by approximately three months, it will allow us to carry out the enabling works efficiently and prevent further disruption in the years to come when this work would need to be carried out as part of the government’s Storm Overflows Discharge Reduction Plan.

“While the extension will be constructed now, it will not become operational until 2026 as additional upgrades are required on our network to enable it to function as designed. These will be carried out in the coming years and the extension tunnel will become operational in 2026.”

Once again, trenchless technology will be used to keep disruption to a minimum while laying the sewer extension. This reduces the need to close footpaths as it lays pipework behind it and sends the earth back to the staging site where it is cleaned and recycled for use in other projects in the area.