Drought has prompted Thames Water to pump groundwater from West Berkshire into the River Thames to keep London water supplies up.
The West Berkshire Groundwater Scheme (WBGWS) is run by the Environment Agency and was commissioned in the 1970s as a drought augmentation scheme for Thames Water. Its job is to add groundwater into the Thames via tributaries during dry spells.
The scheme has 32 pumping stations linked to 10 outfalls by 87km of pipeline across West Berkshire. The boreholes sit in seven wellfields: Lambourn, Shefford, Winterbourne, Upper Pang, Lower Pang, Enborne and Loddon, taking water from the Chalk and Upper Greensand aquifers.
Thames Water can ask the Environment Agency to operate the system under its Drought Plan. The scheme was built after the severe 1943 and 1944 droughts to bolster supplies.
The Thames area is currently in drought - July was the driest month there since records began in 1891. Thames Water said it has seen large increases in customer demand and rapid storage loss in its West London reservoirs, and has activated its Drought Plan and a Temporary Use Ban (hosepipe ban) from 23 July 2026.
The Environment Agency planned to start operating the scheme on 24 August 2026, with an initial phased switch on of the Pang, Enborne and Loddon wellfields.
"We plan to deliver up to 100 mega litres per day to the River Thames to support Thames Water abstractions for public water supply," said the Environment Agency. "Use of the remaining three wellfields (Lambourn, Shefford and Winterbourne) is not currently planned as part of the current phase but will be kept under close review in the coming weeks as the drought develops."
Operation will boost flows above current low levels in the River Pang, lower River Enborne, lower Foudry Brook, lower River Kennet and lower River Loddon, and there will be more Environment Agency staff in these areas to carry out enhanced environmental monitoring.
Niki Hinman, Local Democracy Reporter
