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The Los Angeles Aqueduct Is Wild

practical.engineering

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Re: The Los Angeles Aqueduct Is Wild

#71

Post by andrewflnr »

ceejayoz wrote: post #62
simtel20 wrote: post #41

Earlier quoted context omitted.

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

https://www.nycfoodpolicy.org/10-facts-you-may-not-know-abou... > New York City’s water (including drinking water) is unfiltered, making it the largest unfiltered water system in the country. Were New York to begin filtering its water, it would cost the city approximately 1 million dollars per day to operate the filtration plant. They have hundreds of sampling stations to check daily. https://www.nytimes.com/2025/05/…

Ok, but unfiltered does not imply untreated. Maybe that's where they got the idea, though.

Re: The Los Angeles Aqueduct Is Wild

#72

Post by rtkwe »

detourdog wrote: post #70
fhdkweig wrote: post #67

Earlier quoted context omitted.

If it includes the time it takes to produce that gallon, there would be enough information to do the energy calculation.

I guess it would be 48W/h as it makes about 1.5 gallons an hour.

Which to scale back up and complete the comparison to the state of the art in lab "batch reverse osmosis" systems I was originally talking about that's ~12.7 kWh/m3.

Re: The Los Angeles Aqueduct Is Wild

#73

Post by patmorgan23 »

kccqzy wrote: post #65
hamdingers wrote: post #38

Earlier quoted context omitted.

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 internationa…

So why hasn’t that been done? Have some representatives and senators set limits on almond exports. Surely they wouldn’t be voted out in the next election given how farmers are outnumbered.

Because farmers are making money off of exporting and have significant lobbying power

Re: The Los Angeles Aqueduct Is Wild

#74

Post by coryrc »

com2kid wrote: post #28
strongpigeon wrote: post #16

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.

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!

No, it's not an insane engineering achievement. It's just a normal one, because nobody else has floating bridges, nobody else needed it. It's also years late and costs 10x more than it should.

It's also the wrong stupid technology. The trains are constrained on space because of the low-floor bullshit. It's the longest light rail in the country, it's too fucking long and slow. Even if we fully built out ST3 it can't handle more than ~20% of commuters. It can't be expanded with express tracks because it's built deep underground, so the commute is so much slower than the equivalent in other countries and will NEVER compete with the automobile except during peak rush hour. The northern stations are next to the freeway so over half the land that could be transit-oriented development can't be, and then what's left is devoted to parking anyway. Complete, total waste of a once-in-a-lifetime opportunity, built and planned by people who don't and won't ever use transit.

That 10x cost directly makes it so we can't build out our system properly and we keep building out car infrastructure because people would rather have a car and save 2 hours a day commuting.

Re: The Los Angeles Aqueduct Is Wild

#75

Post by coryrc »

BryantD wrote: post #18
strongpigeon wrote: post #16

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.

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. :(

The commute is slow because the light rail is slow. It's the wrong technology for commuter rail and there are too many stops. (I'm assuming you live north).

(more details: https://news.ycombinator.com/item?id=47457884)

Re: The Los Angeles Aqueduct Is Wild

#76

Post by schlauerfox »

strongpigeon wrote: post #16

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.

We're literally right now building a huge high speed rail project that is planned to link san diego to san francisco through LA, bakersfield and fresno. Progress is made on it daily. https://www.youtube.com/CAHighSpeedRail

Re: The Los Angeles Aqueduct Is Wild

#77

Post by coryrc »

zardo wrote: post #54
BryantD wrote: post #18

Earlier quoted context omitted.

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. :(

Can't do highspeed rail because it's too impractical and expensive, while we're spending a west coast highspeed rail network worth of money on the least popular war in US history.

California is spending the money and what they're building is useless (oh big passenger demand from Merced to Bakersfield, fuck right off with that) and costs 10x what China, France, Japan, etc pay.

Re: The Los Angeles Aqueduct Is Wild

#78

Post by JumpCrisscross »

smm11 wrote: post #39
rtkwe wrote: post #14

Earlier quoted context omitted.

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.

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.

> California pays other states to take its excess solar energy

Intermittently. Essential services like water (with expensive fixed costs) aren’t a good fit for absorbing variable supply.

> Power for a project like this isn't the issue

California has the country’s most expensive power [1] in part due to policymakers constantly assuming it’s free.

[1] https://www.electricchoice.com/electricity-prices-by-state/

Re: The Los Angeles Aqueduct Is Wild

#79

Post by mutagen »

kenhwang wrote: post #57
jedberg wrote: post #45

The norcal/socal divide caused by the river is funny to me. I grew up in LA, then moved to the Bay Area for college. In LA we never really talked about where our water comes from. But we were always 'in a drought' and always taught to conserve water. My wife grew up in the Bay Area, and was told the same. But her family is from Sacramento. Up until about 15 years ago, everyone in Sacramento paid the same for water (b…

Owens valley, where LA "steals" water from, is on the eastern side of the Sierras. NorCal, including Sacramento, is on the western side of the Sierras. So unless they planned on pumping the water over/under the mountain range that surrounds it in every direction except for towards LA, that water was never available for any NorCal city to use.

The California Aqueduct delivers water from the western Sierras through the Central Valley and to Los Angeles. This is likely what NorCal refers to when they say SoCal is 'stealing our water'.

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

Would be interesting to see the relative amounts of use by LA and by agriculture in the Central Valley though.

Re: The Los Angeles Aqueduct Is Wild

#80

Post by valarauko »

ceejayoz wrote: post #62
simtel20 wrote: post #41

Earlier quoted context omitted.

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

https://www.nycfoodpolicy.org/10-facts-you-may-not-know-abou... > New York City’s water (including drinking water) is unfiltered, making it the largest unfiltered water system in the country. Were New York to begin filtering its water, it would cost the city approximately 1 million dollars per day to operate the filtration plant. They have hundreds of sampling stations to check daily. https://www.nytimes.com/2025/05/…

It's largely unfiltered, but it is still treated for disinfection. Chlorination and UV is standard for NYC water, and its fluoridated as well.
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