Mogden sewage works [photo : eight2O]

With the recent boat races having brought with them the annual hand-wringing over river pollution, providing the Mayor with an opportunity to remind us of his 2024 pledge to make London’s rivers swimmable within 10 years, it seems an appropriate moment to review the status quo in this long running saga.

In addition to the annual boat race related news, there have been a number of stories in the wake of the recent Thames Water TV documentary and the related Tideway Tunnel or ‘Super Sewer’ completion, after more than a decade of construction.  The programme revealed a team of people battling the odds to keep an overstretched system working, and not always winning. It must be disappointing for those working on the project to have so much of the news created by the things they were working for years to fix.

There’s the small matter of the automatic outfall monitors now mandated by OFWAT which, connected directly to Twitter, became an effective way to allow the public to beat the water companies with their opprobrium.  It may be that there were plenty of spills before these monitors, but that nobody could put a number on them, and the increasing heavy rainfall episodes have clearly not helped.

Original Super Sewer plans

Notwithstanding the connection to the Super Sewer at Hammersmith under the watchful eye of our own Capability Brown, and at Fulham on Carnwath road, there have been quite a range of related stories that help illustrate the causes, effects and work being done – or not – to address them, here’s a roundup:

1. The Super Sewer’s starting point at Acton Storm Tanks, cutting it’s way under the Hammersmith/Hounslow boundary to the river under Hammersmith Terrace, always seemed to be more of a financial decision than an engineering one. 
   Mogden Sewage works in Isleworth, at the heart of the recent Thames Water documentary, has long been a cause of river pollution hereabouts, and this remains an issue, regularly featuring on the @ThamesCSOAlerts automated Twitter feed, in fact no less than seven times in January 2023 when they shut it down, presumably through embarrassment.  Mogden is their third largest works, and only 4 1/2 miles as the crow flies from our end of the super sewer. Tests before this year’s boat race showed that the worst pollution was by Chiswick bridge, again notably upstream of the super sewer about halfway to Mogden. We might reasonably conclude that while the sewer is helping a big stretch downriver, unsurprisingly it may not be helping our stretch quite as much.
2. 

   TDRA [Thames water]

   Mogden is such a problem, that you might wonder how they missed connecting it to the new sewer – but they already had another plan. The snappily named Teddington Direct River Abstraction plan (TDRA) a plan originally to replace 150 million litres of water a day of river water with Mogden’s effluent as a drought resilience measure, has not gone unnoticed by civic societies in the area, the GLA and others, creating yet more public concern over an already difficult situation, and causing the plan to be scaled back. 

3. Seventeen million. That’s the statistic that stood out from the many recounted to highlight the late Queen’s seventy years on the throne. This is the number of additional people in the UK since 1953.  But has our infrastructure increased by 30% (or more in the South East)? Those providing it, as evidenced in the TV programme, know that it hasn’t, and the strain is showing in the rivers, NHS and housing.  A recent Insight from the London Forum reveals that London’s official population actually fell for the 50 years following 1939, and doubtless we became complacent, as the greater South East area grew less obviously in the stats, while still relying on the same river Thames. But the population is now back near it’s all-time high at 8.9 Million, having been growing since the early 1990’s, with significant recent growth in outer London, hence the problems for Mogden.
4. Those of us born before the advent of the Internet knew that something was wrong in the sea. In our childhood there was definitely coal and raw sewage dumped there in an unholy mix. Those brave enough to surf in it shared the anecdotes, and Surfers Against Sewage was formally born 35 years ago, out of a historic underground movement. It’s not a new thing.
5. Recently, perhaps the single most surprising story was carried in our recent weekly email c/o Chiswick W4 – that of misconnected sewers – sewage and surface water drains mixed up. It seems incredible that, with the amount of legislation, inspection, planning and building control regulation that we witness, such schoolboy errors could be made, resulting in whole new developments apparently sending their foul water directly into the outfalls instead of the sewers. Even more so that it’s been left to eagle-eyed campaigners to identify the problem, that Thames Water knows about it, and hasn’t either done something itself, or requested those with legal powers to do so. Cock-up, rather than conspiracy, but with suitable testing, this sort of thing should be eminently fixable.
6. Locally, flooding during sudden downpours remains an issue as reported several times in the last year by affiliate BRA, contributing to local river pollution. As completion of the Super Sewer neared, we were surprised to hear that a curiosity of the Victorian sewer arrangements in the middle of the borough and eastwards into RBKC, which we reported under the original banner ‘Counters Creek‘ a decade or more ago, means that the issue won’t be adequately addressed by this development after all. This, despite the huge pumping station behind Distillery Wharf, and the multiple local connections listed. A separate flood alleviation project under this name is/was being debated as of 2023, a report detailing the problem produced by Thames Water, but no significant actual construction planned or funded for fairly obvious reasons. This appears to mean that spillages will continue to some extent.
7. Notwithstanding all of that, wildlife is actually returning to the Thames, particularly the lower parts where perhaps the effects of the super sewer and deindustrialisation is greatest, but it sometimes makes the news locally, with recent examples of seals and dolphins.

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