I Have Used This Title Before
In case your memory stretches back to March 2020, when we were looking at the Oroville Dam as it's spillway collapsed, whilst the emergency spillway had long since eroded into chaos.
Well, now we're looking at a completely different dam, and a dam collapse that I'd not heard of before, despite a worrying interest in large hydrographic structures collapsing. This, if I may, is a brief item about the Auburn Cofferdam collapse. I apologise for the picture quality, since they are from a video tape of 1986 sophistication, which is to say, not very. Art!
That straight white line running at a slant from port to starboard is the top of the cofferdam itself, and behind you can see the level of the reservoir, which barely has any water in it. To port at mid-centre you can see a spillway, right next to that bendy road. The cofferdam was intended to keep the waters of the American River back whilst a permanent concrete dam was constructed, and a diversion tunnel was bored into the rock on the north side of the cofferdam, leading to a discharge point well downstream, to carry away the reservoir water whilst the concrete dam was built.
It's important to note that the cofferdam (hereafter "CFD") wasn't a permanent structure and was designed to fail in stages were water levels to rise excessively high.
Did they rise excessively high? Of course they did, or we'd not have a story! Major flooding thanks to rain and meltwater from the Sierra Nevada began flowing into the Auburn reservoir on 18/02/1986. Art!
You can see how high the water in the reservoir is, and how it has begun to flow down the spillway and erode it. The idea is to gradually release water, not have it breach the CFD and abruptly destroy it. Art!
The upper picture here shows the diversion pipe positively and enthusiastically gouting forth torrents of floodwater. The second picture shows how much water has flowed out of the reservoir, where levels can be seen to be decreasing. Art!
These pictures are the "After", viewed from downstream looking upstream and from the west side of the dam. It's plainly obvious that half the CFD has been eroded away and very little water remains in the reservoir, at which point you might throw your hands in the air and exclaim "What a disaster!"
WRONG!
The Auburn CFD was designed to fail progressively, meaning that it still controlled the flow of water downstream, instead of allowing a tsunami of floodwater to travel like a ten million-ton battering ram*. This is important because, one mile below the CFD - Art!
- stands Folsom Dam, managing the water flow for the city of Sacramento and it's half-a-million citizens. Thanks to the Auburn CFD's gradual collapse over nine hours, Folsom was able to manage the water flow without being overtopped; even if it was a little close-run at times.
The ironic ending is that a permanent concrete dam at Auburn is vanishingly unlikely, due to the ruinous cost and the discovery that it would sit unpleasantly close to an earthquake fault. Sorry, Auburn.
I think Art needs new glasses.
Or a bit of Tazering**.
"Around The World Under The Sea"
No, nothing to do with Jules Verne, even if there may be a touch of his DNA about this film's parentage.
You see, Conrad was idly wondering and pondering yesteryon:"What's that film about a submarine anti-volcano mission with David McCallum?" because it's stuck with me all these decades (at least four) after seeing it once on television. A touch of Google-jitsu and - Hay Pesto! Art!
I think there were giant eels, but what sticks with me was a vertically-mounted chessboard, adhering to one of the submarine's walls - because that's a more efficient use of space than having it sit horizontally, taking up needless space. Art!
Hmmm, breaking the fourth wall, are we?
Despite looking at a lot of stills, Conrad cannot find any with that chessboard in shot. Sorry about that.
Well Well GET YOUR TEETH OUT OF MY BEHIND!
Conrad has cued-up "We Have Ways", to see what Al and Jim are pontificating about today, it being Thursday and their second podcast of the week, and - what are they hob-nobbing about today? - why 'Operation Chastise', that's what.
What? That means nothing to you? Guy Gibson? 617 Squadron? THE DAMBUSTERS?
That'll need more than putty to fix.
Trust the Coincidence Hydra to come sneaking in when our attention is diverted, listening for the ever-present threat of infiltrating steam locomotives -
ANYWAY I have discovered I cannot type these words of wit, wisdom and wonder and listen to "We Have Ways", so any denouement will have to await.
I also have some bites to attend to
O Go On
I've been good so far, up until now, but my Inner Rage can no longer be denied, so we are going to resort to CODEWORD COMPILATION COMPLAINING! in a return to form. These are from days ago, since they'd run out of MEN at the supermarket yesteryon. Let us proceed.
"STYMIES": Conrad was originally going to vent volcanically about how we don't need any more South Canadian slang imported, ta very much, when he checked in the Collins Concise (always conveniently close to hand). Apparently this is a golfing term, used to describe a situation where an opponent's (right word? not up on golf jargon at all) ball - stop me if I get too technical - is between your ball and the 'hole'.
WHAT ARE WE EXPERTS IN THE DULLEST SPORT IMAGINABLE NOW? ARE WE? ARE WE!
Bah.
I hope you hit it and BOTH explode.
"ANIMA": What? After consulting my Collins Concise, this is a term from Jungian psychology, used to -
You know what? I DON'T CARE! JUNGIAN PSYCHOLOGICAL TERMS? ARE YOU DOG BUNS JOKING! <pauses to let blood pressure lower>
Analyse this.
"BRIO": This is a musical term, isn't it? About bashing away at the keyboard with lump hammers or similar. Even if it wasn't, Your Humble Scribe has now decided that what it is. 'Con Brio' in musical terms now means 'Hit the keyboard with a pair of hammers as hard as you can.'
Halfway there!
And, with that, we, like the joint, are done.
* Sorry, can't be bothered to work out mass accurately.
** Or both!
No comments:
Post a Comment