4 ms·

Human civilizations have built population centers close to sources for fresh water for millennia. Cities like Los Angeles that require moving vast amounts of fr

Human civilizations have built population centers close to sources for fresh water for millennia. Cities like Los Angeles that require moving vast amounts of fresh water long distances to be viable are a recent phenomenon - appearing only in the last century or so. So a big reason for the lack of desalination is a lack of demand. Yes, some places are experiencing a lack of water but those are the exception to the norm. And even if a population center does need more fresh water, desalination is competing against traditional options: digging wells, building aqueducts, and expanding reservoirs. And have lots of experience - again, literally millennia of experience - implementing these pieces of infrastructure. So in summary, desalination isn't seeing widespread adoption because it's not necessary for most places and we have much more experience with the alternatives. That said, it's great we're still improving desalination and it puts the world in a better place if water scarcity gets to the point that traditional water infrastructure is not sufficient.

jcranmer 6y ago
> Cities like Los Angeles that require moving vast amounts of fresh water long distances to be viable are a recent phenomenon - appearing only in the last century or so. That's not exactly true. The Hohokam started building canals in the Sonoran Desert maybe 1500 years ago (some of which form the basis for the modern water supply system of Phoenix!). Somewhat earlier than the Hohokam, the Romans were infamous for their aqueducts, the longest of which stretched over 250 miles. That's longer than the aqueducts that supply New York City or even Los Angeles!
- manfredo 6y ago
  The California aqueduct system has a total length of 444 miles and the main branch is 300 miles [1]. More important is the demographic impact of water management: Rome's largest population center was ~1 million people, the Hohokam ~80,000 as compared to the Los Angeles metro's 18 million. Preindustrial populations had very little capacity to built large infrastructure projects like these. Huge population centers consuming substantially more water than is brought to them naturally is a very recent phenomenon, Roman aqueducts and Hohokam irrigation notwithstanding. In most years Los Angeles imports 80-90% of its water. Situations like these are not possible without industrialized water infrastructure. Los Angeles used to be primarily supplied by the Los Angeles river and its population was correspondingly lower. Human need water daily to survive, and without pumped plumbing building a population center that isn't near a lake, river, or with access to groundwater is effectively impossible. The Hohokam were no exception. Their aqueduct system did not exist to deliver water to the city center, but to their agricultural settlements. Their main population center was along the Gila river. Preindustrial irrigation systems are impressive when considering they were built without machines, and moreso in hostile terrain like the Sonoran desert or Afghanistan [2] - but it pales in comparison to the demographic impact of water management systems built over the last century. 1. https://en.wikipedia.org/wiki/California_Aqueduct https://en.wikipedia.org/wiki/California_Aqueduct 2. https://en.wikipedia.org/wiki/Qanat https://en.wikipedia.org/wiki/Qanat
dylan604 6y ago
Give global warming more time and see where the need for de-salination is at then. The droughts in SoCal are going to keep making these traditional fresh water sources you mention even more scarce. Less rain means lower lake water levels. Less snow in the winters means less snow pack in the mountains, so less water in the rivers and lakes below. All of this occurring while SoCal has an essentially endless supply of saltwater. Texas is in a similar situation. The lack of natural lake resevoirs means their manmade lakes are also dependent on rainfall that is very prone to drought conditions as well. Texas also has easy access to saltwater. It's places like Las Vegas, Phoenix, etc that will have a hard time getting saltwater. The poplulation of all of these areas are only increasing putting that much more strain on these limited fresh water supplies.
- EricE 6y ago
  >The droughts in SoCal are going to keep making these traditional fresh water sources you mention even more scarce. What's going on in California is nothing out of the ordinary. California is and always was a desert - and building a city the size of Los Angeles there would never have worked had it not been for importing huge amounts of water from central CA (see: Mona Lake) or the Colorado River. Actually most of the Colorado river water goes for agriculture at 1930's water rates that are utterly insanely undervalued - but that's a whole other topic :p
Melting_Harps 6y ago
> So a big reason for the lack of desalination is a lack of demand. Yes, some places are experiencing a lack of water but those are the exception to the norm. With yet another year of drought in SoCal and heavy fires as a result of dryer weather in Norcal seem to suggest otherwise: I don't think it's a lack of demand at all. Carlsbad actually built their desalination (Poseidon) plant when I still lived in CA permanently and the cost was the biggest hurdle, as was waste management, as they sold the water to neighboring areas at a premium in order to recover the costs in a public-private undertaking. Carlsbad is one of the more affluent cities in San Diego County so they had the money during the bubble economy boom before the crash. Another one is/has been scheduled to be rolled out in Huntington Beach apparently [0]. I definitely think desalination should be explored, tested, and refined especially as the CO river source is/has been closed and CA needs to take advantage of the massive resource it has in addition to reducing consumption while figuring out the waste issue with desalination. And nothing could accelerate it faster than CA's massive need for fresh water. A Day Zero situation is something that should be avoided at all costs and in incredibly myopic in what is essentially the 5th largest economy in the World. Personally speaking, I always figured it would be perto-states trying to diversify that would be the biggest financial backers of these facilities, as well as massive solar farms, as the automotive World moved further way from fossil fuel and OPEC goes to ever greater money losing schemes to prop up the price of oil. Especially in a World with evermore cheap and hot fiat being thrown at stupid things like Airbnb and Doordash IPOs. 0: https://angeles.sierraclub.org/news/blog/2020/07/stop_the_poseidon_desalination_plant_in_huntington_beach https://angeles.sierraclub.org/news/blog/2020/07/stop_the_po...
- EricE 6y ago
  If we stopped growing Almonds in the CA desert there would be more water for domestic uses. Agricultural water rates are ridiculously cheap for the value of the water - hence absolutely brain dead schemes such as growing almonds in an otherwise desert!
  - Melting_Harps 6y ago
    > If we stopped growing Almonds in the CA desert there would be more water for domestic uses. Are you seriously advocating that CA, a histrionically Agriculture based State, remove one of its nearly exclusive cash crops to curtail water depletion? Not only is that absurd, but it negates just how quickly that leads to food insecurity. I agree we should divert tax liability for farmers to improve their irrigation systems to reduce consumption and mandate water table depletion instead of letting FAANG and other multinational corps not pay taxes, but this argument doesn't take into account that all the Valley used to be Ag land long before it was ever used planned to be used for every tech corp that wanted to cash-in on a useless app no one cares about. Ag isn't really the problem, the massive influx of people that came here from somewhere else claiming Agriculture is not a critical part of OUR unique Californian Culture, Cuisine and Identity is the issue, and they often do so in order they can have massive pools and manicured lawns and support other useless and wasteful habits. They're the same imbeciles that claim they can come here and remove access to beaches because they bought beach front property and feel they are entitled to everything that surrounds it, which is entirely against Californian Law (as well as beach/surf culture) as beaches are a public good. > Agricultural water rates are ridiculously cheap for the value of the water - hence absolutely brain dead schemes such as growing almonds in an otherwise desert! The central valley remains and has one of the most fertile soils in all of N. America for centuries for a reason, so while almond cultivation in the World certainly suffers from centralization, inefficient pollination irrigation systems, they are correctable with the right incentives and it is most definitely 'worth it' if you understand just how much California feeds not just the US but the rest of the World from that part alone. And honestly, if you have ever been to massive golf courses and school and University campuses with manicured lawns (Pepperdine in Malibu is insane!) you'll see that excessive water is far more prevalent in areas that don't create any value besides aesthetic landscaping and leisure for the few because they have the fiat to buy what ever it takes to have acres of manicured lawns during fires and droughts and since COVID no one is even on campus to 'appreciate' it all. You'd have to be an immense fool to think that not addressing those issues is critical before you remove established cash crops that actually feed people in order to curtail water depletion. Desalination at least solves some issues we could and should address in regards to refilling aquifers and water tables and protect our Cultural heritage, which a big part of it happens to be Agriculture.
Gibbon1 6y ago
Interesting thing about LA. I saw a table that showed how much energy was required to deliver water from each source. Some their sources of water require almost as much energy as desalination. Something like 30-50%. I've wondered about using solar for desalination. Big issue though is desalination plants are capital intensive. So you really want to run them 24/7.
- manfredo 6y ago
  Desalination can be done effectively with thermal cogeneration. It's still inefficient, but since it is using waste heat it's "free" energy so to speak. Saudi Arabia has built such plants. The Soviet Union also built a fast reactor that was cooled with salt water, which was condensed and used as a freshwater supply [1]. Since ~80% of the world population lives on the coast, using seawater as coolant and capturing the condensate could represent a substantial source of freshwater. 1. https://en.wikipedia.org/wiki/BN-350_reactor https://en.wikipedia.org/wiki/BN-350_reactor
- teruakohatu 6y ago
  > Big issue though is desalination plants are capital intensive. I thought the main cost was the running cost of replacing the membranes. I saw a video recently of a modular desal plant that was equipment in shipping containers.
  - Gibbon1 6y ago
    I poked around and the Carlsbad Desalination Plant wikipedia page has numbers. https://en.wikipedia.org/wiki/Claude_%22Bud%22_Lewis_Carlsbad_Desalination_Plant https://en.wikipedia.org/wiki/Claude_%22Bud%22_Lewis_Carlsba... Cost about $1b to built. Energy costs are $49-5m a year. Total cost $108 million. That's inline with my rough memory that 45% of the cost is capital, 45% energy, and 10% maintenance. Fudge those numbers as you will. When I think about the economics it seems complex. Cheap power offsets extra capacity somewhat. Someone that actually manages, designs, plants probably knows real numbers.

jcranmer 6y ago

> Cities like Los Angeles that require moving vast amounts of fresh water long distances to be viable are a recent phenomenon - appearing only in the last century or so. That's not exactly true. The Hohokam started building canals in the Sonoran Desert maybe 1500 years ago (some of which form the basis for the modern water supply system of Phoenix!). Somewhat earlier than the Hohokam, the Romans were infamous for their aqueducts, the longest of which stretched over 250 miles. That's longer than the aqueducts that supply New York City or even Los Angeles!

manfredo 6y ago
The California aqueduct system has a total length of 444 miles and the main branch is 300 miles [1]. More important is the demographic impact of water management: Rome's largest population center was ~1 million people, the Hohokam ~80,000 as compared to the Los Angeles metro's 18 million. Preindustrial populations had very little capacity to built large infrastructure projects like these. Huge population centers consuming substantially more water than is brought to them naturally is a very recent phenomenon, Roman aqueducts and Hohokam irrigation notwithstanding. In most years Los Angeles imports 80-90% of its water. Situations like these are not possible without industrialized water infrastructure. Los Angeles used to be primarily supplied by the Los Angeles river and its population was correspondingly lower. Human need water daily to survive, and without pumped plumbing building a population center that isn't near a lake, river, or with access to groundwater is effectively impossible. The Hohokam were no exception. Their aqueduct system did not exist to deliver water to the city center, but to their agricultural settlements. Their main population center was along the Gila river. Preindustrial irrigation systems are impressive when considering they were built without machines, and moreso in hostile terrain like the Sonoran desert or Afghanistan [2] - but it pales in comparison to the demographic impact of water management systems built over the last century. 1. https://en.wikipedia.org/wiki/California_Aqueduct https://en.wikipedia.org/wiki/California_Aqueduct 2. https://en.wikipedia.org/wiki/Qanat https://en.wikipedia.org/wiki/Qanat

dylan604 6y ago

Give global warming more time and see where the need for de-salination is at then. The droughts in SoCal are going to keep making these traditional fresh water sources you mention even more scarce. Less rain means lower lake water levels. Less snow in the winters means less snow pack in the mountains, so less water in the rivers and lakes below. All of this occurring while SoCal has an essentially endless supply of saltwater. Texas is in a similar situation. The lack of natural lake resevoirs means their manmade lakes are also dependent on rainfall that is very prone to drought conditions as well. Texas also has easy access to saltwater. It's places like Las Vegas, Phoenix, etc that will have a hard time getting saltwater. The poplulation of all of these areas are only increasing putting that much more strain on these limited fresh water supplies.

EricE 6y ago
>The droughts in SoCal are going to keep making these traditional fresh water sources you mention even more scarce. What's going on in California is nothing out of the ordinary. California is and always was a desert - and building a city the size of Los Angeles there would never have worked had it not been for importing huge amounts of water from central CA (see: Mona Lake) or the Colorado River. Actually most of the Colorado river water goes for agriculture at 1930's water rates that are utterly insanely undervalued - but that's a whole other topic :p

Melting_Harps 6y ago

> So a big reason for the lack of desalination is a lack of demand. Yes, some places are experiencing a lack of water but those are the exception to the norm. With yet another year of drought in SoCal and heavy fires as a result of dryer weather in Norcal seem to suggest otherwise: I don't think it's a lack of demand at all. Carlsbad actually built their desalination (Poseidon) plant when I still lived in CA permanently and the cost was the biggest hurdle, as was waste management, as they sold the water to neighboring areas at a premium in order to recover the costs in a public-private undertaking. Carlsbad is one of the more affluent cities in San Diego County so they had the money during the bubble economy boom before the crash. Another one is/has been scheduled to be rolled out in Huntington Beach apparently [0]. I definitely think desalination should be explored, tested, and refined especially as the CO river source is/has been closed and CA needs to take advantage of the massive resource it has in addition to reducing consumption while figuring out the waste issue with desalination. And nothing could accelerate it faster than CA's massive need for fresh water. A Day Zero situation is something that should be avoided at all costs and in incredibly myopic in what is essentially the 5th largest economy in the World. Personally speaking, I always figured it would be perto-states trying to diversify that would be the biggest financial backers of these facilities, as well as massive solar farms, as the automotive World moved further way from fossil fuel and OPEC goes to ever greater money losing schemes to prop up the price of oil. Especially in a World with evermore cheap and hot fiat being thrown at stupid things like Airbnb and Doordash IPOs. 0: https://angeles.sierraclub.org/news/blog/2020/07/stop_the_poseidon_desalination_plant_in_huntington_beach https://angeles.sierraclub.org/news/blog/2020/07/stop_the_po...

EricE 6y ago
If we stopped growing Almonds in the CA desert there would be more water for domestic uses. Agricultural water rates are ridiculously cheap for the value of the water - hence absolutely brain dead schemes such as growing almonds in an otherwise desert!
- Melting_Harps 6y ago
  > If we stopped growing Almonds in the CA desert there would be more water for domestic uses. Are you seriously advocating that CA, a histrionically Agriculture based State, remove one of its nearly exclusive cash crops to curtail water depletion? Not only is that absurd, but it negates just how quickly that leads to food insecurity. I agree we should divert tax liability for farmers to improve their irrigation systems to reduce consumption and mandate water table depletion instead of letting FAANG and other multinational corps not pay taxes, but this argument doesn't take into account that all the Valley used to be Ag land long before it was ever used planned to be used for every tech corp that wanted to cash-in on a useless app no one cares about. Ag isn't really the problem, the massive influx of people that came here from somewhere else claiming Agriculture is not a critical part of OUR unique Californian Culture, Cuisine and Identity is the issue, and they often do so in order they can have massive pools and manicured lawns and support other useless and wasteful habits. They're the same imbeciles that claim they can come here and remove access to beaches because they bought beach front property and feel they are entitled to everything that surrounds it, which is entirely against Californian Law (as well as beach/surf culture) as beaches are a public good. > Agricultural water rates are ridiculously cheap for the value of the water - hence absolutely brain dead schemes such as growing almonds in an otherwise desert! The central valley remains and has one of the most fertile soils in all of N. America for centuries for a reason, so while almond cultivation in the World certainly suffers from centralization, inefficient pollination irrigation systems, they are correctable with the right incentives and it is most definitely 'worth it' if you understand just how much California feeds not just the US but the rest of the World from that part alone. And honestly, if you have ever been to massive golf courses and school and University campuses with manicured lawns (Pepperdine in Malibu is insane!) you'll see that excessive water is far more prevalent in areas that don't create any value besides aesthetic landscaping and leisure for the few because they have the fiat to buy what ever it takes to have acres of manicured lawns during fires and droughts and since COVID no one is even on campus to 'appreciate' it all. You'd have to be an immense fool to think that not addressing those issues is critical before you remove established cash crops that actually feed people in order to curtail water depletion. Desalination at least solves some issues we could and should address in regards to refilling aquifers and water tables and protect our Cultural heritage, which a big part of it happens to be Agriculture.

Gibbon1 6y ago

Interesting thing about LA. I saw a table that showed how much energy was required to deliver water from each source. Some their sources of water require almost as much energy as desalination. Something like 30-50%. I've wondered about using solar for desalination. Big issue though is desalination plants are capital intensive. So you really want to run them 24/7.

manfredo 6y ago
Desalination can be done effectively with thermal cogeneration. It's still inefficient, but since it is using waste heat it's "free" energy so to speak. Saudi Arabia has built such plants. The Soviet Union also built a fast reactor that was cooled with salt water, which was condensed and used as a freshwater supply [1]. Since ~80% of the world population lives on the coast, using seawater as coolant and capturing the condensate could represent a substantial source of freshwater. 1. https://en.wikipedia.org/wiki/BN-350_reactor https://en.wikipedia.org/wiki/BN-350_reactor
teruakohatu 6y ago
> Big issue though is desalination plants are capital intensive. I thought the main cost was the running cost of replacing the membranes. I saw a video recently of a modular desal plant that was equipment in shipping containers.
- Gibbon1 6y ago
  I poked around and the Carlsbad Desalination Plant wikipedia page has numbers. https://en.wikipedia.org/wiki/Claude_%22Bud%22_Lewis_Carlsbad_Desalination_Plant https://en.wikipedia.org/wiki/Claude_%22Bud%22_Lewis_Carlsba... Cost about $1b to built. Energy costs are $49-5m a year. Total cost $108 million. That's inline with my rough memory that 45% of the cost is capital, 45% energy, and 10% maintenance. Fudge those numbers as you will. When I think about the economics it seems complex. Cheap power offsets extra capacity somewhat. Someone that actually manages, designs, plants probably knows real numbers.