What if California's dams fail?

[Ygg2]

https://archive.is/dvuZ8

[sliken]

Was hoping to hear more about other dams, the article focuses on Oroville. Lake Berryessa for instance is a concrete dam, much more like hoover than Oroville. It was built before they realized there was a nearby active fault, the Green Valley Fault.

Lake Oroville (in the NYT article) is the 14th largest lake in California, Berryessa is #11. Lake Oroville does hold twice as much water when full though

The big concern is that Winters was flattened by an earthquake in 1892 and the same size quake at a fault near lake Berryessa, which is only 7 miles from the winters, would breach the dam. I've heard it discussed several times in geology circles, there's even a simulation of the result. It goes poorly for winters (7,000 people or so) and Davis (65,000 people). Here's the simulation: https://www.youtube.com/watch?v=HEJEHnKrueo

[fencepost]

If you look at a terrain map [1] it looks like things flatten out a lot not far below the dam. As you say, bad for Winters and Davis, but not "terrifying wall of water" bad for much else downstream.

[kbrackbill]

I recently read "Cadillac Desert" by Marc Reisner which I highly recommend if you're interested in the history of water issues in the west and California in particular.

A great portion of the book is devoted to dams. The gist of it is that many dams of questionable utility were constructed throughout the 20th century due to pork barrel politics and the unstoppable bureaucratic engines of the Bureau of Reclamation and the Army Corp of Engineers. Like much infrastructure built in the US, not much concern was given to ongoing maintenance and so the book predicts that this will be a larger concern as time goes on.

Hopefully close calls like Oroville will bring more attention to this issue before a larger disaster happens.

[sacnoradhq]

The spillway reconstruction was expensive and time-consuming, but at least it didn't fail that time. The issue was a lack of investment in remediation repairs and improvements, and a lack of planning for extreme event flows.

In the long term, California is unprepared and fucked in terms of dwindling water supply and damaging storms and forest fires from climate change. That's why I left.

[CalRobert]

Pbs made a great series based on the book too.

[s1artibartfast]

The question isn't if but when. If you look at California's geologic record, it has suffered massive flooding every several hundred years AKA Ark storms. The majority of the Central Valley turns into an inland sea in these situations and the locations of many current cities would be underwater.

USGS sediment research in the San Francisco Bay Area, Santa Barbara Basin, Sacramento Valley, and the Klamath Mountain region found that "megastorms" have occurred in the years: 212, 440, 603, 1029, c. 1300, 1418, 1605, 1750, 1810, and, most recently, 1861–62. Based on the intervals of these known occurrences, ranging from 51 to 426 years, for a historic recurrence of, on average, every 100-200 years

[ccooffee]

What separates the Christmas Flood of 1964[0] from these ARK storms? The wikipedia page discusses 1964 as an "atmospheric river".

[0] https://en.wikipedia.org/wiki/Christmas_flood_of_1964

[cgb223]

Waiting for the big flood is kind of like waiting for the big earthquake,

It’s either going to happen tomorrow or 200 years from now, and either way there’s nothing you can do about it except hope you die quickly

[sampo]

Fun fact: In some statistics on the safety of different forms of electricity generation, the largest dam failure [1] is left out, which brings hydropower down to same level of safety as nuclear, wind and solar. Our World in Data is an honest source, and reports both values [2].

If you see hydro reported as safe as nuclear, solar and wind (for example in [3]), then they excluded the largest accident. If hydro is 2 orders of magnitude more deadly than nuclear, wind and solar, then they included everything.

    solar 0.02 deaths/TWh
    nuclear 0.03
    wind 0.04
    
    hydro 0.02 without, 1.5 with

[1] https://en.wikipedia.org/wiki/1975_Banqiao_Dam_failure

[2] https://ourworldindata.org/safest-sources-of-energy

[3] https://www.energymonitor.ai/sectors/power/weekly-data-fossi...

[s1artibartfast]

Interesting. Is there a rationale for excluding it?

[roughly]

Daniel Swain, who is quoted in the article, is a fantastic follow if you live in CA - he tweets at @weather_west and is a phenomenal resource for understanding what’s actually driving the weather patterns in California.

[barathr]

I'd recommend weatherwest.com which he runs -- lots of informed folks and Daniel's blog posts.

[bumbledraven]

> he tweets at @weatherwest

actually https://twitter.com/Weather_West

[quercus]

Daniel Swain is a major climate alarmist. Read with a grain of salt.

[indus]

Our family is bunch of armchair hydrologists. Every random few months we trek from Bay area to Oroville to count the bathtub rings and study the drought situation.

Recently we trekked to see the newly formed Tulare Lake. FWIW, Tulare lake ain't evaporating for another 2 years. Imagine the same size storm repeats for 10+ years.

[hondo77]

It's easier to imagine the drought conditions of recent years/decades repeating.

[cleandreams]

Why should we imagine that?

[sacnoradhq]

Native peoples have an oral history that the Sacramento and Central valleys can turn into inland seas during periods of unusual rain.

https://en.wikipedia.org/wiki/Great_Flood_of_1862

[mistrial9]

that event is literally the "punchline" of the researcher in the article

[throwaway1777]

Apparently the non native people of Wikipedia also have a history of it

[trestacos]

Practical engineering has a good detailed walkthrough of what happened at Oroville dam from an engineering perspective: https://youtu.be/jxNM4DGBRMU

[grrdotcloud]

Funny thing no one talks about. Maybe theory. Probably not.

The Sacramento river, if flooded by say the dam failure of Oroville, could reach Stockton. If that happens the city would be a foot or two underwater.

Little does anyone know there are contingency plans to literally blow the levees along the river and flood the nearby (mostly) farming land.

[crote]

Such contingency plans are quite common, are they not? The water has to go somewhere, so better redirect it to the place where it causes the least amount of damage.

[rightbyte]

> If that happens the city would be a foot or two underwater.

Counting from a nominal roof top or street level?

[belorn]

During energy discussions here on HN, a common topic is accident insurance. The general principle is that a power plant should have insurance that cover any and all forms of accidents, covering any costs that such accidents may have on people who live around (or in this case downstream) of the plant. Not much mentioning of this in the article so I assume the costs is paid either by the state or by the individual.

[crote]

The issue is that for some accidents the liability is virtually limitless, so insuring it is impossible. Chernobyl is up to $850B already and it hasn't even been cleaned up yet! That's why governments often act as the "insurer of last resort": there is literally no other way to pay for it.

[hedora]

Also relevant; the Folsom Spillway had a similar problem:

https://www.theonion.com/preemptive-memorial-honors-future-v...

Spoiler alert:

Shockingly, they fixed it a few years later, and got to test it out this year. It apparently worked great.

[FreshStart]

Could one make a damn self repairing by using coolant lines and woodfibers aka https://en.m.wikipedia.org/wiki/Pykrete? I imagine it similar to the bodies repair facilities, using the electricity from the damn to uphold cooling?

[fgededigo]

Even if this was technologically feasible, maybe the cost would be prohibitive. It would be much cheaper to not build the dam in the first place or close it, or just build alternative energy sources (solar, wind, etc.)

[dbg31415]

Good documentary on a historic dam failure in CA.

https://www.pbs.org/wgbh/americanexperience/films/flood-dese...

[bell-cot]

Grimly worth noting:

- The devastating 1862 flood the article mentions ( https://en.wikipedia.org/wiki/Great_Flood_of_1862 ) extended far beyond California - into British Columbia, Idaho, Utah, Arizona, and Mexico

- With zero major dams available (to fail), the 1862 flood destroyed ~1/4 of all taxable property in California, and killed ~1% of the human population of California. (Today, 1% of that population would be ~400,000 people killed.)

- The 1862 flood is obvious in ocean sediment records, as a thick gray layer. Similar thick layers occur every ~120 years, and one of those is ~10X as thick as the 1862 sediment layer. The NYTimes is very annoyingly short of details here, but I found at least a paywalled version of the sediment research: https://www.sciencedirect.com/science/article/abs/pii/S00253...

[samtho]

I live in Sacramento, there is some context the author may not have been aware of.

First off, hydrology and specifically excess water management in the valley is often geared toward irrigation and replenishing ground water. We have areas that are suppose to become flooded to keep the pressure off of the earthen levees along the river and delta (created by the confluence of the Sacramento to and San Joaquin rivers) as the water drains into the San Francisco Bay. This gives us a way to slow the discharge of water give it time to soak in join the water table. There are improvements here like widening the river channels we’ve carved out to expose more surface area for it to soak into, but there are no plans for this afaik.

Second, we have a network of creeks, canals, and drainage ditches that move excess water to less harmful places, Dry Creek (which is dry most of the year) was carrying water as it should in march. These provide essential, perennial habitats that were once naturally occurring, and are filled and let dry by design.

Like most new media coverage, with this article being no exception, there is a tendency to focus on the main dams, but in the case of the American River, there are 5 dams in all managing water flow, with a dozen or so more impounding various tributaries. Combined this is known as the Upper American River Project, which acts a extra power capacity that SMUD (Sacramento’s community-owned power company) can turn on quickly. This network holds back nearly 430,000 acre/ft of water. A cascading failure in these dams can cause a significant portion of this (with the total capacity being released as almost 1/2 of Folsom’s capacity) could cause a spillway event and a wall of water careening downstream and potentially rupturing levees that were not rated for this volume. Because of the nature of the river’s bend and the narrowing of distance between the banks, the most obvious spot a break would occur is near Sacramento State University and would fill up the River Park neighborhood instantly given that exists between two levees when a new one was built to restrict the flow of the river so they can build more homes. The floodwaters would make it to downtown, destroying the affluent area of East Sacramento, Midtown, and running south through land park, elmhurst, and oak park. This is just one disaster scenarios that could lead to post-Katrina New Orleans type of flooding, with only hours of warning to execute a poorly planned evacuation.

The upper American River project series of damns is fairly well maintained, but for every Sierra Nevada snowmelt River that drain into then Sacramento or San Joaquin, there is a similar network of dams at varying levels of repair, waiting for a large cascading failure event to give the poor unsuspecting towns in the valley an unfortunate surprise.

[jpwerty]

This is an absolutely toxic bit of cynicism. Please delete it.