Danger looms at California's Oroville Dam


#1

Originally published at: http://boingboing.net/2017/07/31/danger-looms-at-californias.html


#2

I suppose this is much hard to fix than just start pouring concrete down the sides until you build up and other couple or four feet?


#3

My guess is that the real estate market below the dam is a pretty tough sell.


#4

Just came back from the area. was there to help a retired friend look over property out of the 500 year flood zone & above 1k elevation. He snapped up a 20 acre farm’ette, with a very nice 50’s farm house for $150k all cash deal. Sucks for the folks below the flood zone, they got’a wait it out for a fix on the damn Dam.


#5

Gotta hope the Damned Dam Isn’t really Damned or he’s Doomed That kinda Drama is a Drag

Seriously best of luck to your friend


#6

Dams don’t have “natural springs”. They are not supposed to have unplanned voids or little zones of permeable material.
There is some cool math to predict and model seepage through homogeneous earthen dams, but irregular zones of seepage are much more likely to be a sign of internal erosion, which is “bad”.


#7

ORIVILLE dam will probably fail do to be earthen, I remember the Baldwin Hills Dam broke about 50yrs ago. It was a title wave. of water, watched on TV when it broke.


#8

I’m no engineer but i’m quite sure it’d be a great deal more complex than that. :slight_smile:
I’d guess if you capped it with another layer you wouldn’t actually fix any of the existing structural problems, just cover them up so it’d be even harder to monitor them.

I’d imagine properly fixing a dam of this type would be an immense task, not far off rebuilding it from scratch for effort required.


#9

While I am in a very different business (IT for the media biz) one thing I can say is, system migrations are inherently more complex than “green field” opportunities. Something tells me the same applies here.


#10

The short answer is: yes.


#11

Isn’t a dam, at its heart, just a mass blocking water? I realize it’s more complicated than that, like the slope and the angle able to hold back the force of the water etc. But at least short term, wouldn’t more mass work? Like boarding up a door against zombies? Then build a new dam a little further down the line?


#12

Did that ever work?


#13

Sure, in Night of the Living Dead the guy lived through the night.


#14

Earthen dams probably shouldn’t be built on top of natural springs.


#15

Dam Sexy!

HrG5JKE


#16


#17

I used to live near a superfund site. It had a dam-type issue where there were a bunch of big rocks holding back a bunch of loose soil and squishy stuff underground. As a dry fixture, this worked. But saturate the interior and the exterior couldn’t really hold it all back. All it would have taken was some sustained heavy rainfall, such as a hurricane to make all that stuff landslide down the hill and kill a bunch of people. The Army Corps drilled a bunch of horizontal monitoring wells to check everything out. Then after data-collection (about a year) they drilled more horizontally and vertically and then pumped concrete strategically in a matrix to hold it all together, internally. Then stabilized the shell even more, and finally, put a thick plastic cap shell on it (to keep the interior from getting too wet) and covered it all over with dirt and planted grass. Seems to have worked. No slide yet. I imagine they could do something similar here at the Oroville dam to stabilize the weak parts.


#18

I know someone who can help:

It can be used to make a boat out of screen doors for chrissakes! A soggy damn will be a piece of cake.


#19

When this happened to the Hume Weir in Australia in the 1990s the root cause was moisture getting in to the core of the dam wall and softening it. Moisture got in because the water level rose above the level which was sealed against water incursion. More concrete on the top may help to seal the dam I suppose.


#20

natural spring” Well that’s okay then. NOT. Plenty of natural things are dangerous as all heck. Snake venom for example. I don’t care where the water is coming from, water inside an earth dam caries the potential to cause errosion and collapse.