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£500k project to reduce storm discharges in Ilkley to begin

Yorkshire Water is set to begin work to reduce discharges to the river Wharfe from a storm overflow on Wyvil Crescent, Ilkley. 

The project, which is being carried out by Mott MacDonald Bentley, is part of a £180m investment project across Yorkshire by the end of April 2025 to reduce discharges from storm overflows. 

Work will take place on the playing field off Wyvil Crescent and is set to start on 17 June. The work will include the creation of a new surface water sewer to separate rainfall from wastewater and is expected to take 12 weeks to complete.   

Yorkshire Water’s partner Mott MacDonald Bentley will be installing five new manholes and constructing a new 130-metre surface water sewer. This will reduce the flows entering the storm overflow during periods of heavy or prolonged rainfall and enable surface water to be discharged to the Wharfe without entering the combined sewer network. It is expected that the surface water separation project will reduce discharges from the storm overflows by more than 50%. 

Omair Khan, project manager at Yorkshire Water, said: “Since the bathing water at Ilkley was designated, we have been working hard to play our part to improve water quality in the Wharfe. This latest project follows work at our Ben Rhydding wastewater treatment works and Rivadale storm overflow. It will significantly reduce the number of discharges into the Wharfe from our Wyvil Crescent storm overflow, as we continue our commitment to improve water quality in the river. 

“As well as this work, we are continuing to investigate storm overflows in the area and will be delivering further projects to reduce discharges into the Wharfe during periods of heavy and prolonged rainfall.” 

A new £15m sewer was constructed under Ilkley and became operational in February 2024 and the utility is also investing a further £60m at its Ilkley wastewater treatment works including:


  • increased storage at storm overflows within 5km upstream of the bathing water 

  • additional upgrades including 15,000m3 of storage and a new 4,000m2 aerated rush bed within the grounds of Ilkley treatment works to more than double its wastewater treatment capacity  

  • a new tunnel under the river Wharfe to transport treated wastewater to a new 19,000m2 integrated constructed wetland (ICW) across the river from the existing treatment works 


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