A new pipeline between Swindon and an Oxfordshire reservoir is set to become operational at the end of this month, with the aim of protecting the River Kennet.
Thames Water’s Axford pipeline will connect south Swindon and Farmoor Reservoir, to provide an alternative water supply when river levels are low.
It means that groundwater abstraction will be greatly reduced at Axford water works after the Environment Agency set requirements to protect the River Kennet.
The pipe will also help protect the River Og in Wiltshire.
Charlotte Hitchmough, director of charity Action for the River Kennet (ARK), said: “We’re delighted this new pipeline will protect the little River Og and the River Kennet downstream from Marlborough during low flows.
“The pipeline is very welcome and we congratulate Thames Water and the Environment Agency for making it possible.”
Charity chairman Richard Clarke added: “ARK’s concerted campaign has finally delivered results which will improve the water situation for the rivers Kennet and Og.”
ARK’s campaign to reduce water abstraction from the River Kennet began in the early 1990s, taking the issue to the Houses of Parliament and on an episode of BBC show Panorama.
Rose O’Neill of the World Wide Fund for Nature said: “These rivers are just two of England’s chalk streams suffering from over-abstraction.
“This welcome investment by Thames Water marks the start of a new approach which better values and protects our chalk streams.”