Mass evacuations

What skills to learn, what tools to get
Post Reply
George the original one
Posts: 4231
Joined: Wed Jul 28, 2010 3:28 am
Location: Wettest corner of Orygun

Mass evacuations

Post by George the original one » Mon Feb 13, 2017 2:26 pm

Are y'all paying attention to the evacuation order for 188k Oroville & downstream residents? IMHO, it's proof, once again, that mass evacuations via automobile are not terribly feasible if there are only a few hours left to flee. In your personal plans, pick another method and make certain you're not trying to carry too much!

Different story if there is a 2-day or 3-day notice. You can be more leisurely and there's time for traffic to unsnarl.

User avatar
Riggerjack
Posts: 1723
Joined: Thu Jul 14, 2011 3:09 am

Re: Mass evacuations

Post by Riggerjack » Mon Feb 13, 2017 2:41 pm

Yeah. One more reason to live in the sticks. A disaster would have to be enormous to cause an evacuation big enough to snarl traffic. Something like St. Helen's, again.

I lived in an area that was flooded after the dam broke. I recommend not doing that. I was lucky in that we were moved out, and only in the apartment the next day to hand over keys. Water rushed through about 4feer up the walls, sweeping cars aside, and leaving about 8 inches of very wet, slippery, and sticky mud. Just an unbelievable mess.

With some luck the dam will hold. I did see on NPR, a bureaucrat already getting out in front of this calling for a bigger budget for infrastructure management. Never let a crisis go to waste.

User avatar
Gilberto de Piento
Posts: 839
Joined: Tue Nov 12, 2013 10:23 pm

Re: Mass evacuations

Post by Gilberto de Piento » Mon Feb 13, 2017 3:07 pm

With some luck the dam will hold. I did see on NPR, a bureaucrat already getting out in front of this calling for a bigger budget for infrastructure management. Never let a crisis go to waste.
I don't know the details of this particular dam but in my state there are thousands of dams, most of which no longer serve a purpose since they were originally to power various industries that no longer exist. It is usually cheaper to remove them than to maintain them. Removal allows the river to return to a more natural state rather than a slow moving swamp. Unfortunately people get used to things as they are so we end up spending a lot of money maintaining dams that are not useful.

User avatar
Riggerjack
Posts: 1723
Joined: Thu Jul 14, 2011 3:09 am

Re: Mass evacuations

Post by Riggerjack » Mon Feb 13, 2017 4:53 pm

Yeah. We have old hydro systems, too. But when you pull down a dam, you release decades of silt buildup.

When they removed the dam on the Elwha river, they promised a booming future of salmon and steelhead fishing. Instead, the silt killed most river life, and wiped out the kelp beds at the river mouth. I'm sure it'll be great in a few decades, but this debacle is hardly an ecology win.

Even worse, they often poison the river, before dropping the dam, with the intention of removing invasive species before stocking the desired fish.
Last edited by Riggerjack on Mon Feb 13, 2017 8:37 pm, edited 1 time in total.

User avatar
bryan
Posts: 668
Joined: Sat Nov 29, 2014 2:01 am
Location: mostly Bay Area

Re: Mass evacuations

Post by bryan » Mon Feb 13, 2017 5:51 pm

Anywhere to read more informed reports about the ongoing status of the dam? I was surprised that they used the emergency spillway (the erosion it caused was to be expected). I wonder what measures they can take right now to get things under control before it is too late (if not already)? More rains on their way..

From my naive googling, ballpark figure shows Lake Oroville capacity is 1.7% total annual supply of CA, on average. Or annually, 39% of urban usage or 10% of agriculture usage.

edit: sensor data: http://cdec.water.ca.gov/cgi-progs/queryF?ORO

User avatar
Riggerjack
Posts: 1723
Joined: Thu Jul 14, 2011 3:09 am

Re: Mass evacuations

Post by Riggerjack » Mon Feb 13, 2017 7:15 pm

My impression was that the emergency spillway is ungated. It is literally the low point in the dam. When the reservoir reaches that level, it spills over the edge. All the water pouring over the emergency spillway is the current intake minus the flow of the main spillway at 100% capacity.

The article I read on NPR showed a spectacular photo of the erosion damaged spillway. But when this storm is over, it will be a fairly simple civil engineering job to backfill the eroded slope, and patch the spillway. The current "crisis" is that the river will be higher than it has been since the dam was built, and a few good photos, and a higher local erosion than normal. Unless of course the rains somehow increase more than they already have. The water going over the emergency spillway looked to be about a 1 deep. That is a lot of water! But the emergency spillway was built as a release mechanism, just to ensure that the water level doesn't build up to a dam threatening level.

I am wondering if because of the never ending west coast drought, they were more conservative with the water levels than normal, adding a human error factor to the situation.

User avatar
Gilberto de Piento
Posts: 839
Joined: Tue Nov 12, 2013 10:23 pm

Re: Mass evacuations

Post by Gilberto de Piento » Mon Feb 13, 2017 7:40 pm

I'm sure it'll be great in a few decades, but this debacle is hardly an ecology win.
Someday is better than never. Was there a reasonable alternative?

The dams I have nearby are much smaller than the famous dam on the Elwha. There's no built up silt or flood danger. Most of them never produced electricity - they ran sawmills and gristmills.

I think your mind is made up on this but http://damnationfilm.com/trailer is a good anti-dam film for those that are interested in the issue.

User avatar
Riggerjack
Posts: 1723
Joined: Thu Jul 14, 2011 3:09 am

Re: Mass evacuations

Post by Riggerjack » Mon Feb 13, 2017 8:18 pm

It's really hard to tell by the news coverage, but if you look at Google maps, satellite view, the emergency spillway is on the north end of the dam. Water just flows over the side there, and I imagine there was a ditch along the road there.

The road is washed out, and there is a new minicanyon eroded there. Now the state is using helicopters to drop boulders in there to slow erosion. I would have used dump trucks and an excavator, and the existing road, but that hardly says crisis like helicopters, I guess.

User avatar
Riggerjack
Posts: 1723
Joined: Thu Jul 14, 2011 3:09 am

Re: Mass evacuations

Post by Riggerjack » Mon Feb 13, 2017 8:35 pm

I'm all for eliminating dams. I like healthy fisheries, and opening more of the river to fish is a fine goal. Run of river hydro is a better way to get electricity, (better for the environment) anyway.

However, the way dams are removed is a disaster. I have never seen a case of one being removed that wasn't a disaster.

I can't imagine a dam without silt behind it. How would that even be possible? Water behind a dam slows down, and drops any silt it is carrying. Even if the river flowed through a granite watershed, there would be silt. The only unsilted reservoir I can imagine would be behind a new dam.

And the problem with rivers is you have that constant run of water, and any drop in the water level leads to a massive increase in water speed, and erosion.

Maybe if they dredged behind the dam first, but that brings its own problems. And even more difficult, for there to be a change in how dams come down, there would have to be an admission of all the damage done by current methods. Nobody involved wants that.

User avatar
Riggerjack
Posts: 1723
Joined: Thu Jul 14, 2011 3:09 am

Re: Mass evacuations

Post by Riggerjack » Mon Feb 13, 2017 8:44 pm

I could imagine a syphon system to slowly dredge the reservoir over many years before removing the dam.

But again, money, time, and acknowledgement of the real world harsh realities would probably kill any projects not already underway.

User avatar
bryan
Posts: 668
Joined: Sat Nov 29, 2014 2:01 am
Location: mostly Bay Area

Re: Mass evacuations

Post by bryan » Mon Feb 13, 2017 9:50 pm

From what I read it was a conscious decision to reduce/stop the flow out of the main spillway (and thus use the emergency spillway). If it was truly an emergency (if the erosion of the main spillway qualifies..), well I guess it will come out in the next few weeks? Seems like they didn't get any use out of that action (other than seeing the damage present).

It seems there is still the possibility of the main spillway eroding to the point of failure?

User avatar
jennypenny
Posts: 5254
Joined: Sun Jul 03, 2011 2:20 pm
Location: Stepford USA

Re: Mass evacuations

Post by jennypenny » Tue Feb 14, 2017 5:49 am

Chris Martenson spoke with an expert yesterday about the specifics of the situation in Oroville ... https://www.youtube.com/watch?v=rl7Sm15unPQ . They also discuss infrastructure problems in general.


ETA: Does anyone know how big an area those power line towers that are close to the spillway supply? You can see them in this photo. Some seem like they would be in the destruction path if the dam failed.

User avatar
bryan
Posts: 668
Joined: Sat Nov 29, 2014 2:01 am
Location: mostly Bay Area

Re: Mass evacuations

Post by bryan » Tue Feb 14, 2017 1:54 pm

Good interview and it matches what I was imagining. Paints a bleak picture of poor infrastructure in the USA... I'm curious why more news sources aren't reporting on the high probability of further eventual failure modes of Oroville. I'm also having trouble finding any live camera feeds or within-the-hour pictures, etc.

George the original one
Posts: 4231
Joined: Wed Jul 28, 2010 3:28 am
Location: Wettest corner of Orygun

Re: Mass evacuations

Post by George the original one » Tue Feb 14, 2017 7:17 pm

Evacuation order lifted, may be reinstated with little warning...

From today's article announcing that people could return home (http://katu.com/news/nation-world/crews ... ornia-life):
Officials defended the decision to suddenly call for mass evacuations Sunday, just a few hours after saying the situation was stable, forcing families to rush to pack up and get out.

"There was a lot of traffic. It was chaos," said Robert Brabant, an Oroville resident who evacuated with his wife, son, dogs and cats. "It was a lot of accidents. It was like people weren't paying attention to other people."

User avatar
Riggerjack
Posts: 1723
Joined: Thu Jul 14, 2011 3:09 am

Re: Mass evacuations

Post by Riggerjack » Tue Feb 14, 2017 8:23 pm

Yeah. Back to the safe evacuation topic.

Often it isn't necessary to get too far away. Had there been a disaster with the dam, just knowing how to get to some back roads into the hills would be a survival trait.

My wife's uncle just bought a farmhouse on the path of the last lahar from Mt Rainier. Now that was 5000 years ago, so he wasn't concerned. My thoughts are that it happened 5000 years ago, so it probably won't happen again in my lifetime. However, I would be looking for the best, second best, and least used path to high ground, because it is going to happen again. Odds are, it won't be useful, but if it is, I wouldn't want to have to look it up at the time.

It's not like any of this is difficult. A few minutes looking at Google earth should do it.

ducknalddon
Posts: 180
Joined: Fri May 20, 2016 5:55 am

Re: Mass evacuations

Post by ducknalddon » Wed Feb 15, 2017 8:39 am

Meanwhile in Mosul, Iraq.

User avatar
bryan
Posts: 668
Joined: Sat Nov 29, 2014 2:01 am
Location: mostly Bay Area

Re: Mass evacuations

Post by bryan » Tue Feb 28, 2017 3:40 pm

Looks like the repair of the main spillway has started, based on outflow sensor data going to zero in the last 24 hours. (recent articles: https://www.google.com/search?hl=en&gl= ... oville+dam)

San Jose flooding was also in the news recently (headlines say $73M damages so far). They didn't get so much warning..

User avatar
jennypenny
Posts: 5254
Joined: Sun Jul 03, 2011 2:20 pm
Location: Stepford USA

Re: Mass evacuations

Post by jennypenny » Thu Mar 02, 2017 3:32 pm

Here's some good recent drone footage. At one point there are workers walking in front of the spillway which shows how large the spillway is. You can mute the video. I don't think the commentator knows what he's talking about.

https://www.youtube.com/watch?v=EkJDAv6myRE

Post Reply