Yorkshire Water invests further £3.8m in Barnsley to protect river Dearne

Yorkshire Water is investing a further £3.8m to reduce storm discharges into the river Dearne with two combined sewer overflow (CSO) upgrade projects near Darfield that feature: 

• £1.9m upgrade at Nanny Marr Road CSO to create 102m3 pipe nest storage
• £1.9m investment at Edderthorpe Lane CSO to create additional storm overflow storage of 177m3

Contract partners M Group started work on the adjacent sites on Monday 22nd June.  Both projects include the creation of a pipe nest solution, capable of storing over 133,000 litres of wastewater during periods of heavy rainfall to prevent it from being discharged into the river. The stored flows will then be sent for treatment once the network has returned to normal levels.

Helen Lynskey, project manager at Yorkshire Water, said: “These projects are part of £1.5bn investment from Yorkshire Water to reduce storm discharges going into watercourses. The Nanny Marr Road upgrade should result in a 70% reduction of storm discharges into a tributary of the river Dearne.  On completion, the Edderthorpe Lane project should result in 69% reduction in storm discharges from 33 per annum to fewer than 10 per year, going into the river Dearne.

“These improvements are part of our £95m plan to upgrade 28 storm overflows to reduce storm discharges across Barnsley including Darton, Genn Lane and Worsborough. Both projects are expected to complete early 2027.”

The new infrastructure projects follow similar work at Dearne Hall Road and Carr Green storm overflows which were completed in 2025.

Storm overflows are designed to act as a relief for the combined sewer network, which carries both wastewater and surface water, during periods of heavy or prolonged rainfall. They discharge when the system is at capacity to prevent flows backing up and wastewater entering homes and gardens. 

Yorkshire Water is reducing the need for storm overflows to operate across the county by building:

• New surface water sewers, to separate surface water and wastewater so that wastewater networks aren’t impacted by bad weather
• Underground storage tanks, to build additional capacity into the network
• Nature-based solutions, to build additional capacity into the network
• Sustainable drainage systems, to slow the flow of surface water into the combined network 

The storm overflow project is part of Yorkshire Water’s £8.3bn investment into its services and the environment over the next five years.