Oroville Dam

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February 13th, 2017 at 4:22:03 PM permalink
Ayecarumba
Member since: Oct 24, 2012
Threads: 89
Posts: 1744
The Oroville Dam in California, with its 770 foot face the tallest in the United States, is in a critical state. After years of drought, the area is receiving record rain fall, and the water the dam holds back had to be released in order to keep it from spilling over uncontrollably. Unfortunately, the "controlled" spillway had a big hole worn in it, so the water was allowed to overflow onto the "secodary" spillway. The "secondary" spillway is basically the lowest part of the rim of the "bowl", so water was basically flowing over the side of the reservoir and flowing through a wooded area down the side of the hill. This can't continue as the erosion is cutting into the earth that holds all the water back. Officials have evacuated 180k+ residents in the potential flood area, just in case the secondary spillway area fails, and a 30 foot wall of water full of trees and rocks comes crashing through the town below.

I wonder what's up at the Gold Country and Feather Falls indian casinos? I don't know if they are in the evacuation zone, but if not, do they have employees left to cash in on the bonanza of displaced people staying at their hotels?




Another thought... After this is all over, I would expect that prospecting for gold would be pretty good since all that soil was moved for the first time.
February 13th, 2017 at 4:49:49 PM permalink
AZDuffman
Member since: Oct 24, 2012
Threads: 135
Posts: 18136
Crazy how it went from drought to floods in no time at all. Although I think that is normal for the American southwest.
The President is a fink.
February 13th, 2017 at 4:55:44 PM permalink
Ayecarumba
Member since: Oct 24, 2012
Threads: 89
Posts: 1744
It is nuts. The secondary spillway was never used before. The area was full of mature trees, and now it looks like someone took a giant potato peeler and shaved off a slice of the hill.

I don't know if Southern California realizes how important fixing this problem is for them. The water coming out of this river feeds the aqueduct that eventually brings fresh water to Los Angeles.

I need to watch "Chinatown" again.
February 13th, 2017 at 4:58:47 PM permalink
buzzardknot
Member since: Mar 16, 2015
Threads: 7
Posts: 497
Love this Chinatown quote
Noah Cross: Politicians, ugly buildings, and whores all get respectable if they last long enough.
February 13th, 2017 at 5:01:24 PM permalink
Pacomartin
Member since: Oct 24, 2012
Threads: 1068
Posts: 12569
Quote: Ayecarumba
I wonder what's up at the Gold Country and Feather Falls indian casinos?


The town of Oroville is 15 meters in elevation below the river level below the dam and 220m below the water above the dam. So it is obviously going to get creamed. The Gold Country casino is much higher than the town (by 100 meters) so it will probably be spared any flooding.

However, Open Street Map is better at showing power lines than the more commercial map programs like Google Maps. Gold Country casino is only 2 miles down the power line that crosses the river just below the dam. So it will probably lose power unless it has extensive backup generators.

http://www.openstreetmap.org/search?query=4020%20Olive%20Hwy#map=14/39.5215/-121.5028
February 13th, 2017 at 5:05:21 PM permalink
stinkingliberal
Member since: Nov 9, 2016
Threads: 17
Posts: 731
Lake Oroville is huge. As recently as two years ago, it was dropping below 30% of capacity. The normal winter of 2015-2016 filled it up somewhat, but it was drawn down as normal over last summer. The filling of the lake to capacity, and with the rainy season not even close to over, took CA water managers by surprise.

In normal times, water managers would keep the spillways going during wet winters to avoid the sort of problems that are happening now. But as this figures to be the first spring that the lake will be at 100% of capacity for several years, the managers have been reluctant to "waste" that water just in case March and April turn out to be abnormally dry.

The casinos at Feather Falls and Gold Country are on Indian land, and as everywhere else in the West, the land that was "given" to the Indians was the crappiest and farthest from the available water. So, ironically, the rezzes are the areas least subject to flooding in the whole Feather River watershed downstream area. And yeah, there isn't a lot of hotel room capacity in the area, as Oroville isn't exactly a tourist destination. I would expect a lot of the evacuees to wind up in Chico, a college town with a lot of hotel rooms. To get to either of the two casinos from Oroville, you have to drive up into the hills a bit, which people fleeing a possible flood may be reluctant to do. Not to mention that to get to the Gold Country casino, you have to drive east on Oroville Dam Drive...
February 13th, 2017 at 5:07:38 PM permalink
stinkingliberal
Member since: Nov 9, 2016
Threads: 17
Posts: 731
Quote: Ayecarumba
It is nuts. The secondary spillway was never used before. The area was full of mature trees, and now it looks like someone took a giant potato peeler and shaved off a slice of the hill.

I don't know if Southern California realizes how important fixing this problem is for them. The water coming out of this river feeds the aqueduct that eventually brings fresh water to Los Angeles.

I need to watch "Chinatown" again.


I highly recommend Marc Reisner's "Cadillac Desert" for an entertaining and informative read about the history of water projects in the West, including a chapter on what happened after the Teton Dam in Idaho failed under circumstances similar to those happening now.
February 13th, 2017 at 5:15:18 PM permalink
Fleastiff
Member since: Oct 27, 2012
Threads: 62
Posts: 7831
ALL earthen dams are subject to erosion from the face of the dam into the interior earth fill. That is why the area near the spillway is not earthern but is concrete or something that will resist erosion. If a reservoir fills faster than the spillway can handle it, the water will simply over flow and in falling down the face of the dam will erode it.

They had five years of drought in California, they did not start drawing down the reservoir early enough. Man made catastrophe. The primary spillway must not have been inspected recently because it should allow water to flow without eroding the concrete, but once it does erode the concrete exposing the earth to the cascading water than the earth gives way rather rapidly and the dam soon fails.

Once the switched to the secondary (auxiliary) spillway it was probably too late to rely on the combined flow to be sufficient. The secondary spillway does not lead water far enough away from the dam.

None of this is new. None of this unpredictable. The only truthful response is 'we hoped the reservoir would not fill as rapidly as it did'.

Acre feet are hard to envision but a 30 foot wall of water cascading towards you and pushing trees, boulders, telephone poles, houses and mud at you more easily grasped.

We all heard about terrorists trying to gain control of our dams, but the real threats are: animals and human operators.
February 13th, 2017 at 5:26:50 PM permalink
stinkingliberal
Member since: Nov 9, 2016
Threads: 17
Posts: 731
Quote: Fleastiff

None of this is new. None of this unpredictable. The only truthful response is 'we hoped the reservoir would not fill as rapidly as it did'.


It's a pity that there already is a "Feather Falls" (impressive, by the way), as the water cascading over the lip of the dam would be quite the tourist attraction. Only Yosemite Falls would be higher than Oroville Falls.

I'm setting aside a week in early May to see the waterfalls in Yosemite. This should be an epic season for that. I was also thinking of whitewater rafting, but the truth is, during really high water years, the Sierra rivers aren't as much fun to raft as many of the rapids "wash out." The opportunities will be on the smaller rivers that normally have short seasons. For example, the Merced below Yosemite Valley is a great day trip but is usually too low to run by mid-June. But this year, it may be runnable all summer--good times!

I recall a lot of fuss and blather during the drought in CA about how the system wasn't well designed and hadn't been able to handle contingencies. Well, five solid years of drought and everybody still had water, and two rainy years and everything is filling back up again, so they must have done something right.
February 13th, 2017 at 6:47:49 PM permalink
ams288
Member since: Apr 21, 2016
Threads: 29
Posts: 12421
Rachel Maddow is doing a segment on this right now. If they put it online I'll post it.

She did an excellent breakdown of what's going on up there.
“A straight man will not go for kids.” - AZDuffman
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