What is the Thames Tideway Tunnel & Why is it Important?

ALK Plumbing and Drainage News, Tips, Advice

What is the Thames Tideway Tunnel & Why is it Important?

thames tideway tunnel feature
What is the Thames Tideway Tunnel & Why is it Important?
4.7 (93.33%) 3 votes

Of all the things that have sparked the curiosity of Londoners this summer, none is more impactful than the Thames tideway tunnel (Harry and Meghan, sorry guys). To be fair, the Thames Tideway Tunnel news has been making waves for a while now and continues to interest Londoners of all ages. Unless you’ve been living under a rock, you must have come across talk about the new tunnel in London and how it’s going to breathe fresh life into the Thames. Read on if you want to know more about the tunnel and why it’s so important for the city of London and the River Thames.

What is the Thames Tideway Tunnel?

Pictured here is the Thames Tideway Tunnel map (released by Tideway). As you can see, it traces most of the river’s path. Click here to download the full map of the Thames tideway tunnel route.tideway tunnel

Before we delve into the importance of the Thames tunnel to London, let’s look at some numbers. The Thames Tideway Tunnel is a sewer that’s 15 miles long, up to 65 metres deep and seven metres wide (which is equal to three London buses placed side-by-side). Also known as the ‘super sewer’, the tunnel is being bored (dug using a machine) under the Thames river and is designed to ease the burden off the Victorian era sewage system.

Although in remarkably good condition, the Victorian-age London sewers are overworked which causes millions of tonnes of sewage to overflow and end up in the tidal Thames river. Once the new Thames tunnel is completed, this extra sewage will be piped to Beckton, where clean water will be separated and the remaining waste used for generating renewable energy.

The sheer dimensions of the project make it the largest of its kind in the UK. It’s an engineering marvel and when you consider how important it is from an environmental point of view, the buzz around the Thames tunnel becomes a lot more understandable.

Tideway has been awarded the contract for the Thames Tideway Tunnel construction, hence the name. The Tideway company is an independent entity and not associated with Thames Water, which is the company that fulfils London’s water and sewage management needs. Once it’s completed by 2024, the tunnel will be handed over to Thames Water for operation. Along with other major sewerage system works like SuDS (Sustainable Drainage Systems) and Lee Tunnel, the London Tideway tunnel is expected to meet the growing sewerage disposal needs of London for the next 100 years or so.

Why is it Needed?

As mentioned previously, London’s existing sewerage system that dates to Victorian times is still chugging along comfortably. However, it was constructed for the requirements of a different period and a far smaller population. The Thames tunnel, on the other hand, will be a shot in the arm for the city’s existing sewer system and make it more efficient while protecting the Thames.

Colloquially known as the Bazalgette tunnel after the man who conceptualised and built it, Sir Joseph Bazalgette, London’s Thames sewer network was built to address, you guessed it right, a highly-polluted Thames river. For years, Londoners disposed of their waste into the closest water stream or river, which eventually made its way to the Thames. By 1858, considered a landmark year in Thames water history because of the ‘Great Stink’, the stench from the polluted river became so widespread and unbearable that it forced Parliament to act.

Bazalgette aimed to tackle this problem through a network of interceptor sewage lines built under embankments in the heart of London. This was a great plan to collect sewage from ‘lost rivers’ like the Fleet and the Tyburn instead of letting it flow into the Thames. However, even this upgraded London sewage system could not have handled the water resulting from very heavy rain. This led Bazalgette to design several overflow points. Called as Combined Sewer Overflows (CSOs), these ducts allowed excess water to flow into the Thames River, instead of flooding London’s streets and entering its homes.

But as the city’s green cover reduced and its population exploded, most streams and rivers on the London sewer map dried up and what were expected to be occasional overflows into the River Thames became an almost weekly occurrence. The London tunnel system, in its current avatar, simply cannot handle the waste generated by a population of over 8 million people.

Sewage amounting to millions of tonnes continues to be released into the Thames. This is causing many pollution-related problems to both Londoners and the city’s environment. People using the river for recreational purposes are at the risk of contracting stomach illnesses and other infections while storms during summer threaten the lives of thousands of fishes because of the sewage reducing the water’s oxygen levels. In other words, a new London sewer system is the only panacea for these ills.

With the completion of the Thames tunnel construction, all these problems will be solved for good. Moreover, it’s among the few public works that have gained bipartisan support. A few other solutions were suggested as well, but none were as cost-effective (the Thames Tideway Tunnel cost is estimated to be around £4.5 billion), disruption-free, and doable as a tunnel under the Thames.

What are its benefits?

Every year, the existing London sewer system discharges several million tonnes of sewage water into the Thames. Once the new tunnel is fully ready, it will intercept almost 95% of the yearly volume of this sewage. It will also capture most of the debris flushed away by the first spell of heavy rains after a period of dry weather. Known as the ‘first flush’, this water contains sediments that have accumulated during the drier months and can cause serious damage.

The Tideway tunnel will also drastically bring down the number of sewage spills. From more than 50 spills per year as of now to under half-a-dozen for the entire year; now that’s a major feat. The tunnel is also expected to trap floating sewage litter that is now clogging up in slower-moving areas of the river.

Most importantly, the Thames Tideway Tunnel will result in a cleaner Thames; a Thames that will be safer for you and your family to enjoy without worrying about illnesses and infections. The London tunnel project will also restore the river’s standing as among the prime nursing areas for species inhabiting the North Sea. A sustained fish population will directly benefit water birds and as a Londoner, you can hope for more regular sightings of dolphins, porpoises and even seals in the Thames.

There is also an economic benefit angle to the Thames Tideway Tunnel project. It is expected to be a major driver of the local economy with over 4,000 jobs created directly. An even higher number of Thames Tideway Tunnel jobs are expected to be created indirectly. Other long-term beneficiaries of the Thames tunnel in London include the local fishing and tourism industries.

At ALK, we’ve built a business out of repairing blocked drains and other sewage issues. For all these years, we made our way around London’s brilliant but ageing sewer system to fix our customers’ drainage problems. That is why we’re so happy the system is getting a much-needed boost with the Thames Tideway Tunnel. If you live in London, or in any of its immediate suburbs, you should be too.

Back to top