Thinking Down and Dirty

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Last week, courtesy of Jazz at @geonetworks, I had an interesting trip down the sewers within sight of the Olympic Stadium in East London - probably the closest I will get to the Olympics. Here follows some info, photos and thoughts from that trip.......

This blog post can be read at 5tth.blogspot.com



We met outside a rather posh hotel in Liverpool Street and during that brief wait, I found myself talking to @superglaze aka David Meyer, who some of you may know from ZDNet. I thanked him for getting the answers I had asked for from JANET about why they had upgraded their core network to 100Gbps. Those answers from JANET are well worth a read if you think a USC of 2Mbps is sufficient......

We took a taxi to Bow and prepared ourselves for the descent into the unknown. White suits, rubber gloves and a rather funky pair of fisherman's socks, all encased in waders. A safety briefing from our inimitable guide, Rob, who I suspect should have his own radio show, and we were hooked up to clamber down the ladder into one of the two barrels which had been closed off for our visit and other maintenance work.

Superglaze gazing downwards....

Once in the barrel, we could see the four ducts coming in from street level. (My iPhone packed up as a camera at this point so further underground photos can be found on geonetwork's Flickr stream....)

These four ducts have 144 cables in each - as should *any* ducting being laid in 2011 and beyond, with 288 in each duct in areas like Docklands and other high density areas. 1 is used for customers and 1 is used for testing. The other two are there for upgrades and to check for degradation faults.

Geo networks has 107km ([Corrected from 50km] of ducting laid in London and 3000km [Corrected from 2000] across the UK. Those ducts are tested against everything you can think of - rats, beer cans, sewage etc. (The ducts are that diameter because rats cannot get their jaws round them to gnaw!). The ducts are laid about 5+ feet up the walls of the sewers to keep them out of the way of "rags", high water level, and jetters. Jetters are like high pressure water jets which come in to clear blockages, and also drag any blockages back along the sewer to remove it, which means loose lay - as H20 have attempted - can be an issue as the fibre can get caught in the machinery. The cinders which we crunched over on the floor turned out to be tarmac which has washed down the gutters over the years. (I suspect it would be preferable not to recycle it, but there's a challenge for someone if we run out of oil to make tarmac to fill in potholes...!)

When choosing where to lay the ducts, Geo first use maps of their network, maps of other networks, and Google Earth and Streetview to analyse the best route above ground. Within the sewers, ducting is usually laid on the opposite side to manholes and entrances to avoid any possible accidental damage. So, in the sewer we were in, the ducting was laid down the right hand side as all further manholes were on the left in the 4 miles to the main processing plant. At the time we went below, across the entire London Geo network, there was a mere 4m of ducting which required re-affixing to a wall. Normally, there is a 4hr time limit to fix customer problems but Geo has had 100% uptime since the vast majority of it was laid in the last 5 years.

Rob told us about Santos, which sounds remarkably like Google's infamous TISP fibre April Fool; but this is a serious solution. The plan is to bring fibre to homes and buildings by bringing the fibre not to the nearest manhole in the street, but through the sewers into the basement etc of the building and then breaking out. This is a particularly great solution for towerblocks etc.....However, rural folk have not been forgotten and there are plans for fibre sewer entry through mini sewers rather than these enormous sewers we were standing in.

When the figures of what was being carried through each duct were provided, I did debate whether I could become a 'sewer rat' and just live down there. 80 wavelengths each carrying 100Gbps, giving a total of 8 terrabits per second - so near and yet so far! 2 years ago, there were a mere 32 wavelengths of 10Gbps each. The IEEE is keeping everyone on their toes by ratifying new standards so the fibre within reach (no, you just wouldn't want to!) was G.652 metro for short hops and in rural areas you would use G.655 for longer hops.

There are no joints within the sewers where possible, and once we got to the huge metal bulkhead door and the false bottom floor maneouvred by chains, you could fully understand why! At that point you began to understand the power of the 'water' that would soon be flowing back where we were now standing.

The engineering within the sewer was astounding. That false bottom and the bulkhead were Victorian and still fully functional, although Rob hammered it home that raising that false floor to drop raw sewage into the Thames was probably treason - definitely a "Here's your P45" offence anyway.

Sir Joseph Bazalgette , who designed the sewers by assessing London's waste problem, guestimating the size London might grow to within the lifespan of the sewers and then doubling his estimates, was a bloody genius who, as Rob pointed out, did not have civil servants, limited budgets, accountants, or quantity surveyors saying, "Those 2p bricks are too expensive, let's use cheaper ones" as he would have today.

Bazalgette's foresight and generosity in diameters and overflow systems works today. Whilst he never foresaw high-rise buildings, nor the phenemonal sprawl that London has 'enjoyed', Bazalgette's approach to raw sewage should be applied today in next generation network planning and build.

We are only going to do this once, and we should be doubling the most generous guestimates of data need, as Bazalgette did with sewage. C'mon, are we so dim as to ignore Victorian engineers who were the envy of the world?

Possibly the worst part for me was seeing the completely numb metal plates that have been placed over the incredible arches the Victorians built to ensure that the overflow level is raised to ensure it will be far higher during the Olympics and will not flood the River Lea, which is part of the Olympic waterway. Future generations will look at these and wonder at a generation who seemed to have little pride in their engineers, and were held hostage to a lack of joined up thinking, profits and built-in obsolence.

The barrels we were standing in sit atop a duplicate set of barrels for the overflow system - a double-barrelled set up! Makes you look at drains in a totally different way once above ground - it's very much an 'iceberg' - far more below than at street level. The arches and walls begin at a height of over 4 ft from the floor and only once the water level passes these walls does the overflow cascade into the lower levels. Each arch is a triumph of Victorian brickwork, now hidden under 21st century cost-cutting exercise.

One of the other Victorian 'niceties' of the system were snow shutes built into the roads. Down these were shoveled snow by the road cleaners, thereby removing it entirely from the London road network, unlike today where the place seems to grind to a halt if an inch of snow falls.

We learn about the install process - plan route, install plastic hangers for the duct, fit duct in gentle curves to ensure no breakage of the glass fibre, blow fibre, connect customers. It all seems so simple. And we know it is, when you remove the chancers who do not have the ethics of our forebears who left a legacy for us in railways, canals, sewers etc. We hear about this current failure to enhance ours and the next generations' lives in a disturbing way....

Often, when planning a route through the sewers, the Geo and Thames Water teams find themselves up against sections of sewer where bombs fell during the 2nd World War. At the time, because obviously, there were other things going on above ground that needed attention urgently, a wall was built around each end of the destroyed section and a pipe shoved through to keep the sewage flowing. In the 60 intervening years, we have done little to nothing to fix those sections of sewer barrels.

Our moral fibre appears to be lacking. Are we building 'best networks' for the next generation, or 'best networks for profits"?

All in all, a highly enjoyable day courtesy of Geo and I will find out the name of the Geo gent who introduced me over a glass of water afterwards to the concept of "From POTS to PANS" - Pretty Awesome New Stuff, which has had me thinking far too much!! (I think it was from Intel some 10-15 years).

It all highlighted why we need to learn the lessons from the past.