The sewer network in the UK regularly spills untreated sewage in to rivers. You can see the scale of the problem on the Rivers Trust map, click below:
This pollution degrades habitat for wildlife and poses a risk to the health of people who paddle, fish or play in the river. Sewage is just one source of pollution, others include farm runoff, road runoff and leaky septic tanks.
Storm Overflows from Sewage Treatment Works
Some sewage overflows from sewage treatment works are permitted under specific conditions, for example extreme storms or snow melt. The river Kennet experiences particularly high levels of sewage discharge when groundwater levels are high. Marlborough and Fyfileld Sewage Treatment Works are especially problematic. For instance during 2020 Marlborough the Sewage Treatment works discharged untreated sewage for the equivalent of 119 days and nights. At Marlborough Sewage Treatment Works neither ARK nor the Environment Agency accept that discharges related primarily to groundwater infiltration are compliant with storm overflow conditions within the permit and, where this is confirmed, ARK will urge the EA to consider an enforcement response.
Temporary discharges from sewer networks
There are further specific problems in the villages of Aldbourne and Lambourn, where in wet winters groundwater floods the sewer through cracks in the pipes, and sewage overflows into the streets. To prevent this Thames Water installed mobile treatment units which partially treat sewage before pumping it into the Bourne. This is a temporary measure, not a long term solution and it still causes pollution.
What is being done by the Environment Agency?
Since 2018, the Environment Agency have required Thames Water to undertake Event Duration Monitoring (EDM) which measures the frequency and duration of storm spills from their sewage treatment works (STW). EDM data is showing where the highest risk overflows from storm infrastructure are located.
Where EDM data shows that water companies are not in compliance with environmental permit conditions the Environment Agency may prosecute the most serious cases or use other sanctions for less serious cases.
At a government level a new task force to end pollution from storm overflows has been estaablished.
What is being done by Thames Water?
Thames Water acknowledge that a step change in investment is required in order to tackle these discharges, so as well as dealing with known point source problems they are gathering evidence to build a case for more comprehensive, strategic investment in the next regulatory period which runs from 2025 – 2030. To achieve this Thames Water is developing a series of plans which can be found at: https://www.thameswater.co.uk/about-us/regulation/drainage-plans.
Thames Water began work in Marlborough last year by relining 186m of sewer and sealing one manhole cover. This is a fraction of the work required to solve the problem. Thanks to Penny Post for this May 2021 update on progress to improve the situation aound Lambourn and other villages.
In January 2023 Thames Water launched their EDM (Event Duration Monitoring) Map, where you can see near real-time storm discharge and the scale of untreated sewage entering our rivers. Click below to visit the interactive map:
What is being done by ARK?
ARK have been campaigning for better sewage treatment since the 1990s when concerted pressure resulted in Marlborough Sewage Treatment Works having one of the first phosphate stripping units in the country installed. More recently ARK and its members have joined the Rivers Trust in calling for an end to sewage pollution. In 2020, 400,000 people signed the 'End Sewage Pollution' petition including many of our members. We asked our MPs to support the Sewage Bill in parliament and we asked our members to urge them to do the same. Five thousand people asked their MP to support the bill and 130 MPs did so, including Laura Farris and Danny Kruger, both MPs in the Kennet Catchment. Elements of that bill have now been included in the Environment Bill. You can read more about that here.
We are supporting Thames Water in the development of their Waste Management Plans by taking part in consultations and planning. We have serious concerned about the slow rate of planned investment, which we have raised with both Thames Water and OFWAT. Meanwhile our members continue to be the eyes and ears of our rivers and and we aare training our volunteers how to spot and report pollution.
We need your support to keep the water companies, the Environment Agency and politicians true to their commitments and make sure that we put an end to sewage pollution and look forward to a healthier river that we can all enjoy.
This information was updated on 15/01/2023
