Oroville Dam: Water and Weather, Engineering and Erosion at the Nation's Tallest Dam
California is having a very wet winter, with multiple atmospheric rivers dumping feet of precipitation in the mountains. Oroville Dam on the Feather River, is the nation's tallest dam, is facing serious engineering challenges. This Storify has some of the best links to a rapidly evolving situation.
- Note: This storify is in reverse chronological order and will be updated as the situation changes. If you don't know anything about what's happening at Oroville, scroll down to the bottom and read upward.
I expect that we will be hearing more about the problems at Oroville Dam for the rest of the winter and spring, because any further big rain and snow melt events will be challenges for the reservoir operation. Beyond that, the repairs, finger pointing, etc. will likely take the rest of year (and beyond). I will plan on updating this Storify "as events warrant."
- I compiled a picture-rich powerpoint show explaining the Oroville Dam crisis and context (up through 9:00 am 2/14/17) and made it available, below. There aren't a lot of words, but if you generally know the story and want something to share with others, hopefully this helps.
- If you want access to slides I compiled on hydrology, erosion, and timeline of #OrovilleDam events, they are here: https://www.dropbox.com/s/ccex3qtlj14h2hc/Oroville.pdf?dl=0 …
Wednesday, February 15, 6:36 pm PST
- On Tuesday afternoon, the evacuation order downstream of Oroville Dam was finally lifted.
- Evacuation downstream of #OrovilleDam lifted. Here's hoping lake levels can be kept low enough that such an evacuation is never needed again https://twitter.com/ER_DavidLittle/status/831621483218677762 …
- By Wednesday afternoon, the lake was dropping dramatically.
- But the weather forecast is ominous.
- While we wait to see what happens next, the broader discussions of dam safety and levees, an even more endangered and undervalued piece of infrastructure than dams.
- "“That groaning sound you’re hearing throughout the Central Valley isn’t the dams – it’s the levees,” says Jeff Mount https://twitter.com/RyanSabalow/status/831931473431138304 …
Tuesday, February 14th, 9:30 am PST
- Oroville Dam Crisis Exposes Flaws in Trump's Infrastructure Plan (public interest ≠ private investment) http://www.citylab.com/politics/2017/02/oroville-dam-flooding-california-infrastructure/516417/?utm_source=twb …
- Someone tweeted and others retweeted the following factoid, and I felt the need to have a little lesson in water balances.
- That doesn't happen though unless the ground is completely saturated, the trees don't intercept any rain, and upstream reservoirs are full https://twitter.com/DataPointed/status/831391364927545344 …
- @drdrewsteen 35.6% of precipitation is lost to evapotranspiration (trees + evaporation) https://pubs.usgs.gov/sir/2004/5202/sir2004-5202.pdf …
- @drdrewsteen Average is only 2.3% of flow is surface runoff, rest moves in subsurface at least part of time (slower) https://pubs.usgs.gov/sir/2004/5202/sir2004-5202.pdf …
- OTOH, I forgot to think about the change in storage of snow on the landscape, so we all fail in our own ways.
- This exchange led to a question about how much water has really fallen on the Feather River watershed in the past few weeks.
- .@TheEarthStory There has been a big rise in lake volume since Feb 1 https://cdec.water.ca.gov/cdecapp/resapp/resDetailOrig.action?resid=ORO … not sure how to translate that to depth
- While I flailed a little trying to put my fingers on exact or basin-averaged numbers, Twitter came through. with the following beautiful images. The Feather River is southeast of Chico and northeast of Sacramento - so the white area on the maps below.
- With all that precipitation, of course the Feather River isn't the only watershed feeling the effects. While our attention has been focused there, rivers have gotten big up and down california.
- The SJR is the San Juan River, flowing through the southern half of the Central Valley. Both the Sacramento River (in the north) and the San Juan River (in the south) are heavily leveed, and the risks of substantial levee failures are rising the longer we have very high flows.
Monday, February 13, 5:45 pm PST
- The finger pointing has begun, particularly as we learn more about concerns raised in 2002 and again in 2005 that the emergency spillway could substantially erode if water were ever let down it.
- Meanwhile, by continuing to pass lots of water through the dam penstocks and the (damaged) regular spillway, the lake level is lowering by about 4" per hour. The goal is to bring it down by 50 feet, but that's going to take quite a while.
- The California Department of Water Resources had a briefing at noon, and KQED has been reporting on it.
- One thing Twitter is starting to speculate about is how much repairs are going to cost and how long they are going to take. I saw $100 million floated to repair the main spillway and that was before the problems emerged with the emergency spillway + the damage is likely continuing to get worse at the main spillway. There's probably more too that we aren't aware of yet.
- Now that the immediate crisis seems to have passed, let's take a few minutes to put this event in hydrologic context. It was the result of a series of big rainstorms called "atmospheric rivers." Atmospheric rivers that rain at high elevations (where there would normally be snow) are sometimes nicknamed the "pineapple express."
- Super-timely article in @earthmagazine: Atmospheric rivers increase California water supply - but only to a point https://www.earthmagazine.org/article/comment-atmospheric-rivers-increase-water-supply-california-only-point …
- Flooding as a result of atmospheric rivers is nothing new to California:
- California's Central Valley has a long history of catastrophic flooding http://www.sfgate.com/bayarea/article/California-due-for-biblical-flooding-arkstorm-10921370.php … via @Mdettinger
- Your periodic reminder that major flooding & major drought are nothing new for California, even back to back. https://www.earthmagazine.org/article/geomedia-californias-climatic-catastrophes-detailed-west-without-water …
Situation as of Monday morning, ~2:30 am PST
- After I hopped off Twitter on Sunday evening, the situation at Oroville Dam got scarier as concerns emerged that the emergency spillway was at risk of failing. 180,000 people were evacuated from lowlying areas along the river overnight.
- A dozen years ago, there were serious concerns that the lip of the emergency spillway would be undercut and fail if the spillway was ever used. That's exactly the situation we're in now, where there are initial signs of undercutting forcing emergency repairs.
- Evacuation order downstream of Oroville Dam is still in place, though hopefully immediate risk is fading since water levels are now below the lip of the emergency spillway and no more erosion should occur unless water starts spilling again. But here's a perspective on the scale of flood risk that we are talking about.
- The Earth Story (@theearthstory) has done a nice job of detailing exactly why the erosion at the emergency spillway is such a concern.
- The next few links are some perspective pieces that I thought were good:
- As the editorial says, we cannot easily attribute a single weather event to climate change, but going from extreme drought to extreme wet fits the pattern of more extreme weather that we expect in a climate changed world. On the other hand, the editorial did not emphasize the need to make sure our nation's infrastructure is well maintained and engineered to cope with more extremes. I was surprised by that omission.
- My take on the longer-term outlook:
Sunday afternoon, February 12th,
Saturday February 11th
- “Climate change is projected to yield both more extreme flood risks and greater drought risks”…so yeah. http://escholarship.org/uc/item/2r71j15r … https://twitter.com/reefmanjohn/status/830459581482594305 …
- Meanwhile over at Shasta, these storms are taking their toll too... http://www.krcrtv.com/news/local/shasta/rising-concerns-for-sacramento-river-caused-floooding/326283106 …
Friday February 10th
- So much water coming into the reservoir that flows down the damaged concrete spillway were ramped up to 100,000 cubic feet per second (cfs) and the possibility of having to use the emergency spillway was first publicly aired.
- It's unclear whether the emergency spillway at Oroville Dam will get used this weekend http://sacramento.cbslocal.com/2017/02/10/dwr-may-avoid-emergency-release-from-oroville-dam/ … but it's going to be intense
- Damage at Oroville Dam may reach $100 million. Millions of hatchery baby salmon being rescued by hand. #CAwater http://abcnews.go.com/Technology/wireStory/latest-emergency-spillway-oroville-dam-45401080 …
- Oroville Dam water levels now only 7 feet from top. emergency spillway may be put to use tonight. http://www.krcrtv.com/news/local/butte/oroville-dam-less-than-7-feet-from-the-top/324494642 … This is BIG!
Thursday, February 9th
- Thursday was the first day that the situation at Oroville came to my attention, though the problem with the main spillway was discovered on Tuesday. Basically, a huge hole had appeared part way down the concrete spillway, causing erosion of the underlying soil and rocks. Even though lots of water was coming into the reservoir, engineers reduced flow down the spillway in order to take a look and hopefully to decrease damage to the reservoir. Meanwhile, the maximum possible water was going through the penstock of the dam itself.
- The latest info and videos coming out of the Oroville Dam & its damaged spillway don't look good. http://www.kcra.com/article/day-3-of-oroville-spillway-damage-where-does-it-stand/8698089 …
- There is an emergency spillway that would be used before overtopping becomes imminent. But using regular spillway = best option. https://twitter.com/PeterGleick/status/829428670578118656 …
- The tweet above from me was correcting an erroneous tweet from Peter Gleick (below) (who otherwise has been pretty good on this event). It is important to understand that dams are built with multiple safety valves for progressively worse situations. Going over the top of the main face of the dam would be beyond the worst possible scenario that engineers imagined.
- Pretty spectacular damage on the spillway of the rapidly rising Lake Oroville (CA) Dam https://ww2.kqed.org/news/2017/02/07/engineers-assess-spillway-problem-at-oroville-dam/ … #cawater