Unbiased evaluation has estimated that greater than half of Thames Water’s 351 sewage remedy works are at present working with out enough capability to deal with the volumes of sewage they obtain.
Analysis performed by the volunteer-led Oxford Rivers Enchancment Marketing campaign (ORIC) has recognized 181 remedy works falling in need of required capability. Of those, 94 have between 80–100% of the required remedy capability, 70 function between 60–80%, and an alarming 17 websites operate at lower than 60%. In some circumstances, similar to Hanwell and Bourton-on-the-Water in Oxfordshire, services are estimated to be treating lower than half the sewage they obtain.
An absence of remedy capability results in untreated sewage discharges (storm overflows) taking place extra continuously. A lot of the worst-performing works are discovered exterior of London in headwater streams and tributaries of the River Thames, the place uncooked or partially handled sewage is prone to be extra dangerous to the river ecosystem, as small waterbodies can’t dilute pollution successfully.
This seemingly complete analysis, spanning over two years, was primarily based on knowledge secured by way of Environmental Info Requests from Thames Water and cross-referenced with inhabitants figures. Required remedy capacities have been calculated utilizing a technique permitted by the Setting Company. While not formally permitted by the regulators, these figures nonetheless give a sign of areas the place sewage works are dealing with capability points.
The findings at the moment are publicly accessible by means of a brand new interactive map on the Oxford Rivers Undertaking Portal. Environmental charity Thames21 has helped to develop the Oxford Rivers Undertaking Portal with its companions.
Commenting on the Oxford Rivers Enchancment Marketing campaign’s report, John Bryden, Head of Enhancing Rivers at Thames21 and Regional Growth Supervisor at The Rivers Belief, mentioned: “Thames Water’s underperforming sewage works have to be upgraded to satisfy trendy regulatory necessities — the place housing progress is deliberate, upgrades to sewage works are wanted earlier than the event is constructed.
“Swift motion is required, significantly in headwater streams. This could occur by means of a mix of conventional gray options, like constructing greater remedy tanks, and lining sewers, and inexperienced options similar to sustainable drainage techniques and remedy wetlands. By making this knowledge public, we goal to empower communities, environmental teams, and native authorities to name for quick infrastructure upgrades.”
The publication of this map comes shortly after a significant Ofwat investigation, which discovered that in 2021 Thames Water breached environmental allow circumstances at 157 websites and was fined £104.5 million for failures to keep up and improve its belongings appropriately.
ORIC co-founder Mark Hull mentioned: “It’s astonishing that Thames Water seem to not know the remedy capability of 120 of their sewage works. It’s much more astonishing that of the remaining 181 works, over three quarters have tanks and pipes which are too small to deal with all of the sewage arriving when it rains.
“This has brought about a rising tide of uncooked sewage discharges into the River Thames over the six years since automated monitoring. In 2020, 22 works discharged uncooked sewage for greater than 38 hours per week (a working week) however that determine had virtually doubled by 2024. In the meantime, the whole hours spent discharging uncooked sewage from these works with insufficient capability greater than doubled to 120,000 hours final 12 months.”
Tessa Fayers, Thames Water’s Waste and Bioresources Director, mentioned: “We all know how a lot folks take pleasure in and admire rivers, which is why over the following 5 years we’ll ship a report quantity of funding to handle our ageing infrastructure and meet the calls for that include inhabitants progress and local weather change.
“We’re dedicated to seeing waterways thrive, however we are able to’t do it alone. Farming, business, highway runoff, wildlife and more and more excessive climate additionally play a task in river well being. We consider that each one storm discharges to the surroundings, even when permitted, are unacceptable, nonetheless, it’s essential to keep in mind that they system was traditionally designed on this approach to stop sewage backing up into properties. This is a matter that can take a few years and important funding to resolve and is on the coronary heart of our Storm Overflow Motion Plan.
“Transparency is on the coronary heart of what we do, and we have been the primary water firm to publish an actual time knowledge map on our web site exhibiting all storm overflows, earlier than it grew to become authorized requirement to take action.”
The map of all sewage works will be accessed, and the total dataset downloaded at https://oxfordrivers.ceh.ac.uk/knowledge/casestudy-tw-stc.
