Possibly addressing the Californian wildfires, president Donald Trump claims that in California "water coming from the north" is "being diverted into the Pacific Ocean".

Governor Jerry Brown must allow the Free Flow of the vast amounts of water coming from the North and foolishly being diverted into the Pacific Ocean. Can be used for fires, farming and everything else. Think of California with plenty of Water - Nice! Fast Federal govt. approvals.

—Donald J. Trump, 7:43 pm · 6 Aug 2018

Finding a list of rivers of California is pretty easy. The accompanying map shows that while not strictly from the north, a lot of rivers in California do flow from the northeast, which can be interpreted as "north".

Are these diverted into the Pacific Ocean?

Alternatively, is there any other water coming from the north that is being diverted into the Pacific Ocean?

Does California have "vast amounts of water coming from the North", "being diverted into the Pacific Ocean"?


The implied claim that these supposed diversions are in any way hindering firefighting in the region, has already been addressed elsewhere.

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    "Diverted" is an odd term too. You don't have to divert a river in California to get it to flow into the Pacific Ocean - it does that all by itself. (With some exceptions). – Nate Eldredge Aug 10 at 16:14
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    Almost all of northern California is in the Pacific Ocean watershed. It is typically the water that doesn't make it to the Pacific Ocean that is being "diverted". – mob Aug 10 at 18:14
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    @user3169 I'm not interested in the political implications; I'm actually interested in the geographical / ecological claim. Living in Europe, I'm not up to date on Californian geography, but I find it hard to believe rivers are being diverted into the Pacific Ocean. – SQB Aug 10 at 20:32
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    If you are not interested in the political implications, then you should not use an unsourced political reference to base an earth sciences question on. – user3169 Aug 10 at 21:50
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    @user3169 but it's not an earth sciences question; it's a question about a claim. A claim about (a part of) the USA, made by the President of the USA. – SQB Aug 10 at 22:06

Not an authoritative source , just a blogger, but a decent attempt to explain some of the cali water issues that's reasonably well sourced itself.

California receives a total of 80 million acre-feet [99 km³] of water per year. Of those, 23 million [28 km³] are stuck in wild rivers (the hydrological phenomenon, not the theme park). These aren’t dammed and don’t have aqueducts to them so they can’t be used for other things.

...

14 million acre-feet [17 km³] are potentially usable, but deliberately diverted to environmental or recreational causes. These include 7.2 million [8.9 km³] for “recreational rivers”, apparently ones that people like to boat down, 1.6 million [2.0 km³] to preserve wetlands, and 5.6 million [5.9 km³] to preserve the Sacramento River Delta. According to environmentalists, this Sacramento River Delta water is non-negotiable, because if we stopped sending fresh water there the entire Sacramento River delta would turn salty

...

It's possible that the claim is based on something like the view pushed by the wall street journal

The Wall Street Journal says that farms are a scapegoat for the water crisis, because in fact the real culprits are environmentalists. They say that “A common claim is that agriculture consumes about 80% of ‘developed’ water supply, yet this excludes the half swiped off the top for environmental purposes.” But environmentalism only swipes half if you count among that half all of the wild rivers in the state – that is, every drop of water not collected, put in an aqueduct, and used to irrigate something is a “concession” to environmentalists. A more realistic figure for environmental causes is the 14 million acre-feet [17 km³] marked “Other Environmental” on the map above, and even that includes concessions to recreational boaters

enter image description here

Conclusion: Sorta.

It may depend on what you consider diverted to mean, if you only count when you divert water out of a river and into an aqueduct then release it somewhere else like into another river or wetlands that eventually sees it enter the ocean then this only seems to happen to a relatively small amount of water.

If you count water that you could easily divert at the press of a button to other uses like agriculture but instead allow to remain in the rivers flowing into the ocean then a larger fraction would count.

If you use a very broad version where you count overarching political choices about where to build dams and aqueducts and choices about economy vs ecosystem (which I believe would be an unreasonably broad interpreation) then you might count most fresh water that you allow to flow into the ocean.

Even the strict interpretation where you only count actual physical diversions include a few percent of cali's water which is a lot of water in absolute terms or relative to cali urban use.

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    Farmers? Environmentalists? I'd say they're both people of the population. – fredsbend Aug 10 at 15:01
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    Your two quotes contradict each other: the first one essentially claims that yes, there’s water being diverted. The second one explains that, no, these “diversions” are called wild rivers. I intensely dislike that you call this explanation “pushing a view”. – Konrad Rudolph Aug 10 at 15:08
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    @KonradRudolph: I see no contradiction. They are both saying precisely the same thing about the same 14 million acre-feet of water. – Kevin Aug 10 at 15:15
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    @Murphy can you add an actual conclusion as well? As it currently stands, your answer is mainly a bunch of quotes. – SQB Aug 10 at 17:30
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    Meh. It might be industry jargon (or might no, I don't know), but the use of the word "diverted" to describe water going where it would have gone without human intervention is ... manipulative? I mean, it's the water that is taken from it's natural flow patterns and channeled for human use that is being "diverted". And that might be the right thing to do, but the to use the word in the opposite sense is disingenuous. – dmckee Aug 10 at 23:59

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