In the autumn of 2004 The Westbourne became our first venture into the realm of London's drainage network.
We had been looking to access the big three, Westbourne, Tyburn, Fleet,
for sometime, The Westbourne just happened to present itself as our first option. There's a fascinating amount of history to the
Westbourne, which I've touched on a little in the text beneath the pictures below. The mid way point section of The Westbourne that we
first explored is a complex mass of chambers, junctions, weirs, and stairways, all perfectly brick formed.
Entering at an overflow chamber, heading downstream brings you into a junction chamber where the Ranelagh sewer meets with the overflow
and a storm relief. Downstream a little further brings you upon an almighty monster of a chamber, here a brick built weir
divides the Ranelagh sewer from its storm relief sewer, The Egg, which cuts beneath it East to West at this point.
The chamber has been laterly re-inforced with I-bars and is an incredible swirling mass of masonry. Immediately after this chamber in the main tunnel is
another weir, of the wooden slated variety to allow it to be raised or lowered by adding slats, with slats in place at its lower edge
it would send the flow from the main pipe via two large holes in the wall down into the storm relief.
Downstream further you encounter the intercepting weir for the Low Level #2 interceptor, another wooden slated job, spanning the width of the main tunnel it diverts all the flow during
times of low/normal capacity down into the intercepting sewer. Beyond the weir the main sewer pipe is dry for a while, all its flow having been sent down the interceptor,
it soon starts to pick up flow from many varied shapes and size of branch sewer and you find yourself trudging through some icky nasties again.
Following a variety of shape changes of the main sewer the downstream journey is halted, just beyond a hydraulically operated stainless flap-o-doom. The flap can entirely seal the tunnel,
just beyond it a stainless steel section of pipe terminates in a hinged steel plate with a small aperture in the bottom to allow flow through. There's no way
past for explorers, why not just push the hinged plate you say? Likelyhood is that the hydraulic flap-o-doom is an automated system, set to seal off the tunnel downstream of here during flood, most likely triggered
by a sensor located to the other side of the hinged steel plate. Push the plate to try to get past and find yourself in an Indiana Jones type scenario (target audience),
that or get sealed in a tiny airtight section of London sewer with no obvious way out, no thank you!
So treking back to the first encountered junction there's the option to head upstream, up the ranelagh's older, shorter storm relief sewer. It's a one mile walk, against the flow of things, things
you generally don't want to accidentally stomp down in and have the splash back hit you in the face! It's a good lesson learnt, no matter how dry and chapped your lips might
be feeling, resist the urge to lick them!!!! So it's a long trek upstream and you kinda get to thinking it's just going to continue on forever with no features
other than the odd access stairway, then finally rounding a bend your torch hits on another almighty mother of a chamber! The chamber, on the Middle Level #1
interceptor, is the starting point of the storm relief and is an amazing feat, the main tunnel opens
out and three arches ahead terminate in brick slides, topped with overflow weirs, over which the Mid Level would pour when inundated. The central slide features
a wooden slated opening which could be removed to allow the Mid Level to overflow into the storm relief, again, not something to be messed with!
A brief history: The Westbourne, also known as the Bayswater Rivulet until the mid 19th Century,
rises from springs on the Western side of Hampstead Heath. From the junction of these streams in the Kilburn area
it meandered a course south-eastwards to the Thames, taking in flows from
various tributaries. One tributary in particular, the Tyburn Brook, joined the Westbourne from the east in the area
of Hyde Park. It is reputed to derive its name from its proximity
to the Tyburn Tree/Gallows, London's
principal location for public executions from the 12th century to 18th century. That said, the gallows derived their
name from the former village of Tyburn in which they were located, which in turn derived its name
from the River Tyburn. If you're not confused already the important point is that the Tyburn Brook
and the River Tyburn are not one & the same!
Getting back to the Westbourne, it's entire lower reaches south of Hyde Park down to the Thames remained open until 1827,
at which time its course from Hyde Park to the present day Sloane Square was altered and covered over, reclaiming marshy land
for housing development. The Westbourne was then, as it had been for some two hundred years previous, a common (open)
sewer. It was designated to carry only surface water, cesspools supposedly taking foul sewage, but its course had become
little more than a huge cess-pit.
The remaining open section on its lower course, from Sloane Square to the Thames, was finally covered over by the
M.C.S. in 1854 following many
years of complaints from local residents.
In Hyde Park the Ranelagh sewer had been covered over by the
M.B.W. by the early 1860s.
During the construction of their
Middle Level Intercepting sewer, 1861 - 1864, they put in place a one mile storm relief tunnel, running south-east through the park
between the Middle Level Interceptor
under Bayswater Road and the Ranelagh sewer as it exits Hyde Park. North of Hyde Park sections remained open until as late as 1871, being
arched over as housing further encroached upon it. So the
Westbourne like its fellow Thames tributaries was arched over and culverted in various stages. By
1874 Bazalgette's West - East intercepting sewer system was complete and had harnessed the flow of the Thames' Northern,
North - South running tributaries
carrying London's sewage to treatment works in the East rather than it emptying into the Thames.
That said the same system is still in use to this day and is sadly inadequate for modern day London, untreated
sewage often breaches the intercepting walls all the way down to the Thames itself
during heavy rainfall.
