(filled with mud)
- - - - - - - - - - -
(Continued from The Maze)
The entrance from the Maze to the Hangar is from a large RCP pipe which branches
off from the main line. You'd never suspect what was at the end of the pipe-
it looks just like any other.
The Hangar is a massive stormwater detention pipe; presumably used to provide
extra capacity to the drainage system during times of heavy flow and also
to catch sediment/pollutants during periods of low flow. The Hangar would
be responsible for draining an underpass at a major intersection on a large
freeway- the only water flow that enters it comes from here. Physically, the
Hangar is shaped like a long box- about 2.5m tall x 4m wide, and over 100m
long.
Coming to the Hangar, it becomes immediately apparent that something quite
different from your average drain lies up ahead. The RCP disappears, replaced
by a vast darkness. There is a huge metal gating set up in front of the pipe-
it stretches across the Hangar, from one wall to the other. Known as the Cowcatcher
to UEA, it would seem the purpose of this huge metal addition is to prevent
large pieces of debris from washing downstream into the Maze. I don't know
how large debris (tree branches?) would get into the Hangar in the first place,
but they would accumulate on this grate instead of clogging up the system
down the line.
Underneath the Cowcatcher is a deep pit, shaped like a long rectangle. I think
it is a sediment trap, and I have no idea how deep it actually is, because
I wasn't about to walk into it (UEA says over a metre deep). In order to get
into the Hangar, you have to hug the wall of the RCP while stepping around
this pit onto a ledge near the side, then cross through the Cowcatcher.
Inside the Hangar proper, the floor is covered with a good six inches of sediment.
Resembling blackish mud, this stuff is common to every storage tank I've seen,
and indicates low (or constrained) water flow. Walking through the mud causes
small pockets of trapped gases (created by decomposing material) to escape
into the air; and soon the area will stink like rotten eggs.
The Hangar is huge, and I've been wanting to see it for a long time. Although
it's not as big as Thunder Road in Edmonton, it is the single largest storage
tank pipe I have ever been in. If not for the black mud covering the floor,
it would be a really cool drain to play around in. But aside from the fact
that it's big, it doesn't have very many interesting features. The Cowcatcher
is an interesting piece, but that's about it.
I walked the length of the Hangar, and was surprised to discover another set
of footprints in the mud. I couldn't find where they originated from, but
there seemed to be a single, slightly filled-in set of tracks that went one
way and then walked back.
At the far end, there was and RCP leading out that was identical to the one
leading in. I followed this for a short way, before it ended in a large manhole
room. This room was cool, because it was large and entirely empty, and the
floor was a flat sheet of ice. There is a small pipe leading into this room,
and looking inside, I could see light at the end. I had to check it out, and
after a bit of crouching, I emerged into a small chamber with a grated ceiling.
The walls and floor were covered with ice, and it looked to be a large inlet
for the drain. The RCP continued, so I kept on following it.
At the end of this pipe, I came into another, larger, chamber. This one also
had a grated ceiling, but was twice the size of the previous one. The roar
of vehicle traffic was loud and encompassing, it sounded like I was in the
middle of a freeway. But the fresh, cold air was a welcome relief from the
stinky Hangar and the normal drain smell; and it was nice to see the sun again.
I sat here for a while and took a rest, before I got cold and had to head
back into the warm drain again.
Down the RCP, I stopped in the manhole room with the ice floor and had a snack.
Then, I trudged back down the pipe into the Hangar, walked through the muck,
slipped past the Cowcatcher and back into The Maze.
- - - - - - - - - - -
Entering from The Maze through the RCP pipe.
Inside the Hangar. Behold the mighty Cowcatcher. The sediment pit is a big black shape at the bottom middle of the photo.
I'm not sure what this thing is. It's midway through the Hangar, and looks like it should be a manhole shaft. But the rungs inside start twelve feet up, and are unreachable.
The inflow pipe, complete with UEA tag and high water marks.
The first little icebox.
Walls covered with ice.
The bigger room at the very end. The roars of traffic were quite loud.