The Los Angeles Aqueduct Is Wild

(practical.engineering)

96 points | by michaefe 2 days ago

13 comments

  • gorfian_robot 1 hour ago
    Being from LA, I am used to a water system that works without needing power. I think most of CA is like that. It was a surprise to lose the water back east when the power went out during a storm.
    • larkost 6 minutes ago
      I wonder if this was in an apartment building. We owned a condo in a 5 story (4+1) apartment building and because it was taller than the San Jose water system was built for, our building needed (electric) pumps to provide water pressure to the building (there were tanks on the roof). If we lost power, then we lost water.

      Now that we have moved to a 2 floor detached home (also in San Jose) we do not have that issue, and everything is gravity fed.

    • macNchz 20 minutes ago
      The only places I've heard of losing water during power outages are houses that use a private well (no power, no well pump), which would be the case anywhere. Municipal water systems may or may not use power to provide pressure, but are going to have generator power outside of the most severe outages.
      • MrZander 7 minutes ago
        Also, water towers. As long as the power isn't out long enough to deplete the tower.
    • duomo 51 minutes ago
      The LA water system is dependent on power as a whole. There’s many pumping stations along the various aqueducts.
    • devilbunny 47 minutes ago
      I know NYC doesn't treat their water at all, but LA doesn't either?

      My city runs on surface water, so we have treatment and then pump to storage tanks. You would have to be out for quite a while to run the city out of water, though - the tanks are large.

      • simtel20 1 minute ago
        Where did you get that idea about NYC water being untreated? NYC treats its water. Chlorine is added if and when needed. Testing stations exist to evaluate water quality all around the boroughs, etc.

        You can't have a city of millions of people and have the water be potable from the tap without testing and treatment

      • kenhwang 36 minutes ago
        LA definitely treats the water. Both the surface water before consumption (I'd be surprised if any city doesn't do this) and the wastewater, for reclamation for nonportable use like irrigation, and for recycling back into the general clean water supply.

        The aqueduct water is specifically purified by the Los Angeles Aqueduct Filtration Plant. That plant is gravity fed, but it doesn't operate without power.

        LA just has the advantage of having mountains in the city, so it's cheaper building more elevated water storage so the capacity lasts longer during power interruptions (which are also not as common or extended as they are in the east). They will still eventually run out if they're not replenished by powered pumps.

  • z3ugma 57 minutes ago
    "Well There's Your Problem" on the collapse of the St Francis Dam, mentioned in Grady's video https://www.youtube.com/watch?v=hxLgM1vnuUA

    Also I love when they refer to it as the "_First_ California Water Wars" in a grim realization of the future of water scarcity in the West

    • hamdingers 6 minutes ago
      There is no water scarcity in California, only misallocation. The vast majority of our water is heavily subsidized and used for agriculture, and a substantial amount of those crops are grown for export, yet agricultural exports makes up an insignificant part of California's economy.

      We could end all California water scarcity talk today, with no impact to food availability for Americans, by curtailing the international export of just two California crops: almonds and alfalfa.

  • kyledrake 1 hour ago
    I was in Owens River Gorge last week, it's a very interesting place. It has some of the tallest single pitch rock climbing in the world, sometimes requiring 80M ropes: https://www.mountainproject.com/area/105843226/owens-river-g...
  • strongpigeon 1 hour ago
    Sometimes it feels like the US has lost its appetite for grand structural projects like that. Maybe it’s just that I’m unaware of them and that impression is the result of survival bias, but given how impossibly hard it is to just build anything where I live (Seattle), I’m not so sure.
    • BryantD 54 minutes ago
      I don't think you're wrong. Every time someone says we can't do high speed rail it makes me very sad. And as far as Seattle goes... my commute is substantially affected by the I-5 closures. It's somewhat shocking to me that we allow infrastructure to decay as much as we do.

      I'd be happy about the light rail expansion if they weren't talking about delaying the Ballard line indefinitely. :(

      • amanaplanacanal 42 minutes ago
        Evidently tax cuts for the wealthy are more important than infrastructure.
    • com2kid 32 minutes ago
      Seattle just got done building light rail tracks over a floating bridge.

      It is an insane engineering achievement. A train literally running on tracks on a road that is floating on water!

      • strongpigeon 22 minutes ago
        Fair. Maybe I'm too much if the weeds of this because all I can think of is how much of a fight it was to pass ST2 and ST3 and how we haven't even started on the Ballard line despite voting for it in 2016 (10 years ago!) and how it might be delayed forever.
    • jcranmer 41 minutes ago
    • rabid_0wl 30 minutes ago
      Those projects would literally be impossible today with the environmental regulations in place, especially in California.
      • OskarS 1 minute ago
        Certainly that’s part of it, but also just NIMBYism. Los Angeles were able to defeat the Owen’s Valley farmers back then, I don’t think they would be now.
    • dogemaster2025 49 minutes ago
      It’s too complicated to corruptly make money off of a large project like that. It’s much easier to just buy a bunch of drugs and needles and give it to the methheads, or spend money on homeless while building zero homes.
  • mjamesaustin 24 minutes ago
    Growing up in LA, I was fascinated as a kid watching the water flow down this aqueduct. Anytime we drove by it on the way to Magic Mountain, I'd hope that it would be a water-on day.
  • rimunroe 1 hour ago
    I was surprised to find out it was largely uncovered, though I guess it probably makes it much cheaper to construct. I usually think of aqueducts as pipes or tunnels, like Persian qanāts. I wonder how much water is lost due to evaporation.
  • babblingfish 43 minutes ago
    I really dig the editorial viewpoint of this article. New journalism style meets fun facts about engineering.
  • bombcar 2 hours ago
    I wonder at what point the up-front costs of massive desalination would overcome the (often hidden and externalized) costs of projects like this.
    • JumpCrisscross 1 hour ago
      > the up-front costs of massive desalination

      Desalination is dominated by operating costs.

      • rtkwe 1 hour ago
        Correct it's massively energy intensive to filter the salt out the newest best ideas still use ~2 KWh/m3 of water and that's a lab system in perdue that batches the process instead of having it run continuously which is why current RO desalination systems require so much energy.
        • smm11 3 minutes ago
          California pays other states to take its excess solar energy. Power for a project like this isn't the issue, actually building the system is the issue.
    • kjkjadksj 1 hour ago
      I don’t think the brine pollutant issue has been meaningfully solved. You are also now pumping water inland uphill the whole way.
      • SoftTalker 47 minutes ago
        For usage where the water mostly returns as sewage, is treated and then returned to the ocean, you can just dilute the brine with the treated discharge and then it returns at basically the original salinity.
        • kenhwang 21 minutes ago
          It is common now for treated discharge to be sent to a discharge lake/leach wetlands so it can be used to replenish groundwater supplies.
  • anjel 2 days ago
    Nice picture but I've never seen the water anywhere near blue like that.
    • Supermancho 2 days ago
      That's a youtube thumbnail. I believe it's been altered, which also explains the strange brown substance that looks out of place.

      Most of the video content has the correct coloring, from my experience observing the aqueduct.

    • w4der 44 minutes ago
      I think it's edited to look like water he uses in his garage demos.
  • KerrAvon 1 hour ago
    If anyone wants a deep dive on this subject: https://en.wikipedia.org/wiki/Cadillac_Desert
  • hparadiz 1 hour ago
    The California aquaduct system is an engineering marvel.
  • 3happyrobots 2 days ago
    Really enjoyed watching that. Good luck with water LA.