Oroville Spillway is failing with enough rain dam may break

[buckmanriver]

Things are looking scary at the Oroville Dam currently as the spillway is falling apart rapidly as the lake continues to rise.

Anyone, care to chime in on with thoughts on the risk of catastrophic failure?


Oroville Dam spillway hole will continue to erode, state official says | The Sacramento Bee
Spillway crumbling but flows to resume as DWR balances flood threat

[buckmanriver]

Outflow data real time: CDEC - Data Application

[Andy H.]

Man, I hope that spillway's underlain by bedrock! Better call for some RediMix, guys....

[Pinned]

I doubt there will be failure of the gates but the lower spillway is likely completely gone at this point.

[jgrebe]

I think Andy has it right. Not unusual to have serious erosion / damage on emergency spillways during high flow events. Saylorville 2010, and even Glen Canyon in 83 are good examples. Looks scary but what is important is that there is good bedrock structure below the spillway that will limit undermining the dam. My experience is that there generally is but guess time will tell

[Andy H.]

There's a dusty old geotech report that just got pulled off the shelf and is the subject of a great deal of attention right now.

OK, Bonus for the day - I went looking for the passage in Cadillac Desert describing when Glen Canyon Dam's spillway chutes were eroded out in '83, "the put-put of the Briggs and Stratton mowing the lush lawn over the turbine rooms..." and found this instead. Go to the Youtube site and there's a bunch more.

Enjoy!

Cadillac Desert

[restrac2000]

Wow. Watching the West cycle through decades of drought and now epic snowpack is wild. I am betting the political debate over water allotment the next few years in Cental Cali will be as turbulent as that spillway video.

Why are spillways so prone to this sort of damage? Isn't their primary purpose to be used in moments like this, ie shouldn't design incorporate these types of forces? Or are they assumed to perform well enough and repairs just assumed to be part and parcel?

[Pinned]

They are not designed to fail in this or any other way at all. Unfortunately they are rarely used to capacity and are poorly maintained.

[restrac2000]

Sounds like this has potential to severely damage the nearby hatchery.

http://www.sfchronicle.com/bayarea/a...m-10921941.php

[btreat]

With all the attention Oroville Dam is getting, here is some helpful information. The dam is offset from the spillway which runs down a natural hillside. Even the alternate spillway is far away from the dam itself. Here is a link to a descriptive picture.
Spillway crumbling but flows resume as DWR balances flood threat

Originally Posted by buckmanriver

Things are looking scary at the Oroville Dam currently as the spillway is falling apart rapidly as the lake continues to rise.

Anyone, care to chime in on with thoughts on the risk of catastrophic failure?


Oroville Dam spillway hole will continue to erode, state official says | The Sacramento Bee
Spillway crumbling but flows to resume as DWR balances flood threat