The Big Stink continues: Sewage map spotlights dramatic increase of untreated sewage in the Trent and its tributaries

The latest sewage map reveals that the Trent region – covering Birmingham, Leicester, Stoke-on-Trent and Nottingham – has seen dramatic increases in untreated sewage entering our rivers.

This is in line with a nationwide 54% increase in sewage spills in 2023 and shows that the tide of sewage pollution has not turned.

In 2023, the Trent and its tributaries saw over 292,000 hours of sewage being discharged, as part of 42,000+ spills that occurred throughout the year. Compared to 2022, the region saw an increase of 12,000 spills, adding 140,000 hours of sewage entering the Trent and its tributaries.


Sewage spills in the Trent region in 2023

The data, breaking down the Trent region into sub-catchments, reveals that no river in the area remains unaffected. The Rivers Dove, Derbyshire Derwent, Soar, Tame, Anker, Mease, Idle, Torne and Erewash are all subjected to excessive sewage pollution. This is underscored by the fact that no river in England is in good overall condition, and only 14% are in good ecological health.

So why have we seen such dramatic increase in both duration and frequency of discharges, despite loudening calls for improvements?

The answer lies in a sewerage system that is underperforming, not just during heavy rain. Combined sewer overflows, or CSOs – also sometimes called storm sewer overflows, or SSOs – were originally designed to act as pressure valves, an emergency relief system to be triggered only by blockages or the most extreme rainfall events.

This system ensures that foul water won’t re-enter your home – for example, by flowing back up your toilet or drains – if a pipe blockage occurs, or if too much foul water enters the system at once. Sometimes sewage is unable to reach wastewater treatment facilities for one of these reasons and is instead released into rivers via a sewer overflow.

A second reason why the system gets overwhelmed is that rainwater, flooding or snowmelt enters the sewer system. These historic combined sewer systems, where surface and foul water to be filtered by treatment works are carried along together, are still in use in many areas. Often, surface water from rainfall entering combined sewers pushes the system to capacity, which means it then discharges, with minimal filtering, into a nearby watercourse.

This brings us towards the vast increase in untreated sewage being discharged into our rivers in 2023, often linked to heavy rainfall events.

In 2022, we experienced an extremely dry summer, with satellite images showing a potato crisp-coloured landscape, and images of rivers and reservoirs at extremely low levels. This meant we saw a sewage system with little pressure exerted via rainfall – and even so, unacceptable amounts of untreated sewage were discharged into rivers at numerous locations.

Satellite images for 2023 showed a different extreme. Landscapes were submerged in water, rivers swollen and roads were transformed into rivers. Last year saw record levels of rainfall over a sustained period; and with it, a sewage infrastructure system continuously overwhelmed by floods and rainfall.


Aerial footage: Helen Johnson

What the steep increase in sewage spills shows is not a sudden decline of sewage infrastructure within the short space of a year, but a worrying inability of the system to cope with extreme conditions – whether that’s drought or deluge.

Figures showed that sewage was discharged at unacceptable rates in below-average rainfall conditions in 2022, highlighting a sewage infrastructure unfit for purpose and in urgent need of a comprehensive capacity boost.

This was further highlighted in 2023, when a larger issue was also revealed. Urban development and intensive farming practices have contributed towards landscapes and cities that are unable to support our rivers by holding excess water, meaning it is consequently channelled into a sewer system where it doesn’t belong. Walk through any city and you will find few pathways for water beyond the drainage system. This means that urban runoff will either flow into a nearby watercourse, carrying plastics and pollutants straight into the river system, or it will inundate the sewer system.

Does this all start to sound like an overwhelming issue?

Here at Trent Rivers Trust, we’re all about solutions. Let’s break it down…

What you can do:

Don’t go with the overflow and continue to demand better.

This year is an election year and if river and nature recovery sit high on the list of things that would sway your vote, take some time to evaluate your candidates and asking them the following questions:

  • What actions will you take to reduce pollution in our local rivers?
  • How will you encourage sustainable land use practices to protect the health of local rivers?
  • What steps will you take to engage your constituents about the importance of local rivers?
  • What steps will you take to improve access to blue space in your constituency?
  • What are your priorities for mitigating against/adapting to climate change in your constituency?
  • How will you engage with all the stakeholders that must be involved in solving the problems faced by our rivers?

Find out what’s happening near you

A densely dotted sewage map suggests that the chances are, things are likely to be amiss near the places you play, live and work. Visit the sewage map to find out what’s wrong near you and demand better. Contact your MP citing the places local to you that are marked on the sewage map, and explaining how the issue affects you.

The 3 Ps – Pee, Paper and Poo

Reduce the risk of blockages and only flush pee, paper and poo down the toilet. Bin the wet wipes and cooking oils to help avoid rancid, pipe-blocking fatbergs.

Here’s what we’re doing, as your local rivers charity – and what we want to see more of

Nature-based solutions are all-rounders when it comes to addressing the pressing nature, climate and pollution crises rivers are facing locally and beyond. Take the example of rainwater inundating our sewer systems – measures such as green rooftops, planting more trees, and having more planters in our gardens to catch water can help to intercept flow paths, absorb water, and filter out pollutants. These solutions ease the pressure on the sewage system, whilst addressing issues around pollution and increased flood risk. Find out more by following this link.

Creating or enhancing wetlands can be part of natural flood management and ease pressure from combined sewer overflows

While these solutions aren’t a silver bullet, their upscaling is essential to climate and community resilience. Both government and local water companies need to support such initiatives.

What do water companies need to do?

Severn Trent Water, which looks after the Trent region, needs to upgrade its infrastructure to cope with increasingly extreme weather, but also boost the capacity of its sewer system to meet increasing infrastructure demands., Infrastructure improvements could include inbuilt storage tanks to temporarily store water during high usage and periods of flooding, and upgraded sewage treatment facilities, improving the capacity and performance of treatment works.

Both treated and untreated sewage are listed as the second-most significant reason for rivers not achieving good status, following agriculture. While there are many additional issues, including pollution from road runoff, plastic pollution, and barriers to fish migration, such as weirs, within our rivers, it is clear that our waterways won’t recover unless sewage pollution is addressed with ambition, creativity and urgency.

Anything else?

Many others have the potential to helps reduce the amount of surface water reaching our sewage works, including housing developers, local authorities and highway agencies. We need to increase the sponginess of our catchments to store water close to where it falls and let it soak in instead. This is the fundamental ethos behind the nature-based solution approach.

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