A £1.3 million project to help protect the River Avon, which runs through the historic city of Bath in the UK, will dramatically reduce the automatic release of untreated wastewater into the waterway.

The new storage tank will cut discharges into the river by up to three-quarters, by holding increased flows from combined sewers. Combined sewers carry wastewater from homes and businesses along with rain run-off from buildings and surfaces, which arise during heavy downpours.

The tank, which is installed below ground in the carpark at Bath Rugby Football Club's Lambridge ground, is capable of holding more than 170,000 litres of excess water. Some 1,800 tonnes of soil were removed during the project.

Wessex Water says it is prioritising 13 projects to tackle overflows in the region between now and 2025, with an investment of £3 million, targetting those sites that have previously discharged most frequently.

Currently, if there is too much rainfall in the system, the overflow automatically discharges into watercourses, such as the River Avon, to protect homes and businesses from the risk of flooding.

Once the rain has subsided the stored water is then gradually returned to the sewer system for its journey onwards to a nearby water recycling centre, where it is treated before being safely returned to the environment.

Wessex Water’s programme manager Jonathan Barker said, “This project is an important step towards progressively eliminating the automatic operation of storm overflows in the Bath area and contributes towards our target of reducing the number of hours of their operation across our region by around 25% by 2025.

“This is one element of such work we’re carrying out to protect the environment in and around the River Avon, with similar schemes already underway upstream in Bradford-on-Avon and downstream in Hanham in the east of Bristol, while a further storm storage scheme within Bath is also due to be completed next year.’’

Wessex Water is also tackling storm overflows in other ways before 2025, including upgrading sewage treatment methods to increase capacity at 42 of its water recycling centres, including introducing more nature-based and low-carbon treatment methods such as reedbeds and wetlands.