What is the Tideway Tunnel, and how does it affect Vauxhall?

The Tideway Tunnel is a new sewer project proposed by Thames Water to replace the old Victorian sewerage system, which is at capacity.  At present, when there's heavy rain, the existing sewers are entirely filled up (with rain water and sewage), causing the Combined Sewerage Outlets (a type of over-flow tunnel) to discharge sewage into the River Thames. 

The Tideway Tunnel would be an alternative tunnel, used to redirect sewage away from the Thames to Beckton Sewage Works in East London and it would run under the Thames.  In the event that the Tideway Tunnel was built, the Combined Sewerage Outlets (CSOs) would remain in place, but due to the extra capacity granted by the new tunnel, they'd very rarely cause sewerage to leak into the Thames (or, that's the hope, in any case).

Thames Water claim that, at present, 39 million cubic metres of untreated sewerage overflows into the Thames each year (remember, lots more goes in once it's been treated).  Any idea how much that is?  I tried to calculate it in 2 litre coke bottles, and 4 gallon water bottles, but the figure was too large to comprehend.  The best I can translate it into is Olympic Swimming Pools.  So, 15,798 Olympic Swimming Pools worth of untreated sewerage hit the Thames each year.  Eww.  That sounds like a very large figure, but then one has to work out how much water actually flows through the Thames each year to decide if it's as a bad as it sounds.  I'd be interested to hear from anybody that knows.  The EU are not too pleased by the volume of untreated human waste entering the Thames, so the European Commission are taking the UK to court on account of threat to human life and adverse effects on marine environment in the river.  London residents may well have very little choice in approving the Tideway Tunnel plan to improve the health of the river.

Anyhow, on account of all of this, Thames Water are holding a huge London-wide consultation on whether or not to build the new sewerage Tunnel.  The reason it concernes Vauxhall is because Thames Water wish to use Vauxhall as a site for permanent strctures required by the Tunnel and we have two local Combined Sewerage Outlets nearby (clevererly labelled "Clapham" and "Brixton") .  (This fact is slightly confusing because when viewed on this Thames Water map, these CSOs are actually both already located in Vauxhall!  Who knew we had two sewage discharge pipes in our locality?  It's probably not mentioned on the marketing brouchure for Vauxhall Tower :o) ).  The proposal is that a new structure be built at Vauxhall to connect both of these CSOs to the main tunnel.  It wouldn't need to use any existing land because Thames Water are cleverly hoping (at least in three of the sites under consideration) to extend the river wall!

Thames Water have chosen four sites on which they'd like to construct, site 1 (in front of St George Wharf flats on the foreshore), site 2 (in front of MI6 on the foreshore), site 4, the preferred site (outside of 89 Albert Embankment, to the side of Tintagel House) and site 3 (this one would cover the communal gardens and car park of a block of flats in Claylands Road!!).  Site 3 would be an appalling choice, since it takes away a communal garden, and it's miles from the river!  St George's residents and MI6 likely wouldn't approve the other two options, so I'd agree with the proposal document that the favoured site (in front of offices) is preferable.

Take a look at their map:

The Vauxhall site is the only one within the Borough of Lambeth, that would be used for the proposed new tunnel.  Obviously, were it only Lambeth or Southwark that would be affected by the project, nobody would worry too much.  However, multiple sites of work for the Tideway Tunnel have been proposed for boroughs such as Wandsworth, Hammersmith and Richmond, and they're none too happy.  The Guardian's Dave Hill weighed in again today with comments in his roundup, Metropolitan Lines, pointing out that the leader of Hammersmith & Fulham's Council had become especially perturbed by the proposals.  The Councillor's view is that, since only 18 people have been made ill from drinking the water over the last 15 months (we presume they capsized in canoes, rather than willingly drank the water), there's probably not much need to act.  A somewhat short sighted view one might think, if the sewage problem is due to get worse as London's population increases!  But then I might suggest residents protest if I thought the new structure would emit neasty smells!  Since we've already got two CSO outlets at Vauxhall that nobody knew about, I'm not sure whether the proposals will make any difference.

Thames Water point out that if they do use their preferred site (outside of 89 Albert Embankment, to the side of Tintagel House), there will still be an impact on the Albert Embankment Conservation Area and some disruption on the Thames Path during construction.  Construction would take place for three years, after which the site would be vacated as far as possible, although some permanent structures would be installed.  These include a 10 metre tall ventilation column and a small box with electrical equipment in it.  There will be another round of consultation, so hopefully we'll learn more about how the new structures would look if the proposal ever reaches the second round!
There's a document here, Albert Embankment Foreshore, which contains additional information from Thames Water about the building work on the Albert Embankment, as it would affect Vauxhall and shows a visualiation of the small ventilation column and surrounding area.