The agency calls water company “storm overflows” a “safety valve within the sewerage network”, allowing raw sewage and runoff to flow directly into rivers when the network - most of which was built in the nineteenth century - is overwhelmed.
In a report published last week, the agency says pressures such as “population growth and climate change can result in discharge frequency and volume from these overflows increasing over time”, with “implications for the environment and flood risk”.
READ MORE: Water companies and CSOs
In 2018, a total of 146,930 spill events were reported from 6,182 storm overflows, averaging around 24 spills per year from each overflow, according to the report. The figure could be much higher if spills went unnoticed or unreported.
In total, there are about 15,000 storm overflows in England permitted by the agency, it says, although NGO WWF puts the figure at 17,684. Overall, there are approximately 31,000 combined sewer overflows in the UK, according to campaign group Surfers Against Sewage.
The agency says it is running a programme to install monitoring on more than 13,000 overflows by 2020 and had completed around 10,100 by March this year.
The monitoring will “measure how frequently and for how long an overflow operates in wet weather and will be used to inform the water companies' future improvement programmes”, it says.
The agency has also “issued new guidance to water companies on environmental permits for storm overflows and emergency overflows – on issues ranging from drainage strategy, screens, telemetry systems, pumping systems and connections for new developments” as well as “work[ing] with the water industry to develop a consistent planning framework for water company drainage assets”, according to the report.
Reacting to the news, former Undertones frontman turned rivers campaigner Feargal Sharkey said: “These things should only ever operate in extreme situations, perhaps the Environment Agency might care to explain how any of that complies with [the] law and what they’re doing to enforce it.”