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We need more water than rain can provide: refilling rivers with desalination

• ceejayoz 4y ago
  > we must safeguard that hard-earned desert fertility for our descendants Must we?
  • tspike 4y ago
    Initially I downvoted you because I interpreted your comment as abdicating the responsibility to protect the environment for future generations, but reading back through the article I think your intent was the opposite- why should we safeguard the system of diversionary canals and water extraction that created the problems in the first place? It's a valid thing to question that premise.
    • aaron695 4y ago
• nickkell 4y ago
  Solutionism rears its ugly head
  • labrador 4y ago
    I'm curious why you think technical solutions are "ugly." Political solutions seem far more intractable and ugly.
    • JPLeRouzic 4y ago
      If we produce huge quantities of clean water by desalination of sea water, we will produce huge quantities of brine. What do we do with this brine? Certainly not dumping it in the sea? https://en.wikipedia.org/wiki/Brine https://en.wikipedia.org/wiki/Brine
      • sidibe 4y ago
        There you go: https://en.wikipedia.org/wiki/Brine#Wastewater https://en.wikipedia.org/wiki/Brine#Wastewater
        • JPLeRouzic 4y ago
          From your sub-link: "Wastewater brine can pose a significant environmental hazard, both due to corrosive and sediment-forming effects of salts and toxicity of other chemicals diluted in it."
          • labrador 4y ago
            Unpolluted brine from desalination plants and cooling towers can be returned to the ocean. To limit the environmental impact, it can be diluted with another stream of water, such as the outfall of a wastewater treatment or power plant. Since brine is heavier than seawater and would accumulate on the ocean bottom, it requires methods to ensure proper diffusion, such as installing underwater diffusers in the sewerage.[13] Other methods include drying in evaporation ponds, injecting to deep wells, and storing and reusing the brine for irrigation, de-icing or dust control purposes.[12] Seems like a well known problem with some solutions already in place
      • silasdavis 4y ago
        Why not put it into the sea from whence it came?
        • JPLeRouzic 4y ago
          That is dumping it in the sea, which creates a new set of problems. https://www.newscientist.com/article/2190929-growth-of-desalination-plants-is-a-serious-problem-for-marine-life/ https://www.newscientist.com/article/2190929-growth-of-desal...
          • labrador 4y ago
            That article is trash. The link to the study doesn't even work.
  • codefreeordie 4y ago
    "Solutionism" is a fantastic word for this particular slur, since it gets to the heart of why technological solutions to our problems are not considered: because they might solve the problem, thereby robbing the politicians of their ability to wield the problem as a weapon against the population.
    • sidibe 4y ago
      Particularly the idea that we should conserve our way to carbon neutrality instead of figuring out how and spending the money/effort to do a lot of carbon capture drives me crazy. We're not suddenly going to stop pulling ancient carbon out of the ground in the near future, and these same people are always talkig about how we are already at the point of no return, so if you really care about the carbon problem, you'd recognize we need to figure out how to pull some of it out of the cycle (of course it's also good if we don't use too much fossil fuels, but that's never going to be enough and politically impossible, good luck telling the third world they shouldn't consume like we have been doing).
      • beckingz 4y ago
        We should continue investigating methods for carbon capture. But none of them look even close to cost competitive.
        • codefreeordie 4y ago
          That was true of solar power 20 years ago, too. But eventually, we got there. We will probably get there with carbon capture too. Though I do agree, we should focus more heavily on nuclear power now, because it is much closer to ready-for-prime-time than carbon capture. Still, I think that carbon capture is an excellent future technology for the production of carbon-neutral liquid fuels. Liquid fuels are super great, and they can be made into a very clean portable power source through the use of nuclear power and carbon capture tech.
          • pencilguin 4y ago
• ZeroGravitas 4y ago
  This is a bit like carbon capture from the air. Yes, energy is going to be cheap, and yes we can do this, and in some cases we may have to. But there's so many simpler ways to just stop wasting the water we do have, this should be a last resort.
  • akira2501 4y ago
    You can either solve the problem with money, or you can change human behavior with regulatory burden that ultimately depends on force. I'd think you're way better off just solving the problem. Someone else called this "solutionism." Well, this article makes an exceptionally good case that the amount of input cost justifies the output economic activity by more than order of magnitude... so with this in hand, what would the justification be for forcing unnecessary changes in human behavior?
    • lm28469 4y ago
      It's not solving the root cause though, it's more like a bandage on an open wound. Tech allowed us to live in ways that are 10-100x time to wasteful to be sustainable, we should learn to be frugal again
      • akira2501 4y ago
        The root cause is humanity. You cannot "solve" this. You can only force people to do what you want as opposed to what they would want. Our frugality was not a learned trait that we've simply discarded.. it was purely a consequence of our lack of technological progress and the austerity it forced on us. It's the oddest thing to me to live in this world of amazing technological progress, while openly suggesting that throwing this technology away and returning to austerity is the only viable "solution."
  • baxtr 4y ago
    While I would love to agree, I even like it better to see statistics about this. What are biggest lever for saving water? Would you mind sharing?
• wnoise 4y ago
  I agree that we'll probably need to start making a lot more fresh water. I am however confused by the suggestion that any large portion should go towards dumping it in existing watersheds. I would have though that the simplest and most robust thing to do would be just to pipe it directly to existing customers and reservoirs. While many of the reservoirs are actually on rivers, many aren't, and even for those that are, filling way upstream seems incredibly round-about. I looked through the article and couldn't find any real explanation for why this would be reasonable.
  • vermilingua 4y ago
    Because humans aren’t the only consumers of fresh water, and flora and fauna don’t migrate to reservoirs. Refilling rivers is a way to better emulate increased rainfall, reducing our already outsized impact on the ecosystem.
    • icegreentea2 4y ago
      I think OP's point was that more directly transporting water to where it's used by humans is more efficient, and will also remove/reduce that particular consumers impact on existing rivers (therefore reducing impact on ecosystems). To more directly address the OP's point - dumping water into existing resevoirs and rivers allow us to reuse existing infrastructure getting water from source to consumer (at the cost of other inefficiencies). I'm certain the real answer is case by case and if such a system were to be implemented, we would see the whole spectrum of implementation deployed.
    • dzab 4y ago
      Ultimately it would be discharged by sanitary water treatment plants back into the waterways, even if first supplied for human consumption.
  • friend_and_foe 4y ago
    What's being discussed here is a bit of a far flung, post scarcity situation.
• jasonpbecker 4y ago
  This massively underrates the cost and challenge of brine waste remediation and fails to account for the cost to our broader need to reduce carbon emissions by redirecting large solar projects to brand new energy uses versus replacing existing energy infrastructure.
  • jamiek88 4y ago
    Yeah desalination itself is a solved problem now we have solar power what is not a solved problem is the waste remediation. Brine is a real problem that needs solving somehow before massive global desalination efforts can take place.
  • jeffbee 4y ago
    We already have a considerable seasonal surplus of photovoltaic power. We actually disconnect California PV plants in the spring because we can't use the energy they would produce, and we have to pay the operators of those plants for the curtailment. This represents essentially cost-free energy that we can redirect to desalination. As we deploy more and more PV to cover our late-summer peak demands, the spring curtailment will also grow.
  • bushbaba 4y ago
    California could pump the brine waste to the salton sea. Solving two issues at once.
• myshpa 4y ago
  Forests make rain [0][1]. Forests store carbon. Forests protect biodiversity [2]. Forests can be used for food production [3]. Why are we not planting more forests? Amazon was planted by natives several thousand years ago. "Primitives" with hand tools, and we, with all the technology and fossil fuels, cannot/will not? Forget technology. Find place [4][5][6], plant seeds. [0] https://en.wikipedia.org/wiki/Biotic_pump https://en.wikipedia.org/wiki/Biotic_pump [1] https://www.calacademy.org/explore-science/rainforest-makes-rain https://www.calacademy.org/explore-science/rainforest-makes-... [2] https://en.wikipedia.org/wiki/Anthropocene#Biodiversity https://en.wikipedia.org/wiki/Anthropocene#Biodiversity [3] https://www.atlasobscura.com/articles/what-is-permaculture-food-forests https://www.atlasobscura.com/articles/what-is-permaculture-f... [4] hhttps://ourworldindata.org/land-use-diets https://ourworldindata.org/land-use-diets [5] https://ourworldindata.org/land-use https://ourworldindata.org/land-use [6] https://climatehealers.org/the-science/animal-agriculture-position-paper/ https://climatehealers.org/the-science/animal-agriculture-po...
  • martythemaniak 4y ago
    People are raising money to do that too: https://techcrunch.com/2021/06/08/terraformation-gets-30m-to-fight-climate-change-with-rapid-reforesting/ https://techcrunch.com/2021/06/08/terraformation-gets-30m-to... Replanting native forests in deforested environments also requires desalination.
    • myshpa 4y ago
      > Replanting native forests in deforested environments also requires desalination. Probably not everywhere. If biotic pump theory is correct, you could (for example) reforest at the coast, with the forest there established then progress inland, without expensive desalination / water distribution technologies.
      • martythemaniak 4y ago
        You should read some of terraformation's blog posts, they're quite sensible and talk about why you need desalination. Tldr, while forests do create their own microclimate, maintaining moisture, etc you need desalination for the first decade or two while the forest boots up. Also, desalination is largely a function of energy, as solar falls in price, so does the cost of desalination. https://terraformation.com/blog/solar-powered-desalination-reverse-desertification https://terraformation.com/blog/solar-powered-desalination-r...
• mjfl 4y ago
  what we could do, is release carbon dioxide into the air, making the climate warmer, accelerate evaporation from the oceans, and increase rain and snow fall on mountains.
  • gremlinsinc 4y ago
    So fight global 'warming' with more warming or 'fire'? ... That sounds like a very bad idea...
    • mjfl 4y ago
      global warming is generally correlated with wetness, not dryness.
  • pencilguin 4y ago
    There is no idea so bad that nobody will embrace it.
• worldsayshi 4y ago
  My favourite solution to water scarcity is water traps. It seems like such an amazingly simple concept with underrated potential: Make sure that whatever water rains down in a place stays long enough to nudge the micro-climate in the right direction - by digging some water barriers in the right places. While it cannot possibly(?) solve water shortages everywhere it can turn some deserts green: https://www.youtube.com/watch?v=T39QHprz-x8 https://www.youtube.com/watch?v=T39QHprz-x8
  • jamiek88 4y ago
    Also known as swales. There’s a lot of woo and ‘influencer’ stuff in the permaculture world but some real good concepts too.
    • worldsayshi 4y ago
      I've only recently been learning a little bit about permaculture. In essence it seems like agro hacking in a way? A big variety of tricks that you can implement on a plot of land to increase biological values or yield. It sounds a bit like medicine before medical science. A bit of woo is then to be expected?
  • algo_trader 4y ago
    This is an amazing video. The eco-system seems fragile - easily destroyed by over grazing, or even simply from tourists or visitors Also labour intensive - he mentions 100 labourers x multiple years. So these projects would need government regulation and protection.
    • worldsayshi 4y ago
      Sure it's labour intensive to adjust the topography but once it is done it shouldn't need continuous maintenance, as shown in the end of the clip. I also suspect that the fragility is due to it being so newly established. If the foliage is allowed to become dense and put down proper roots over time it should become more robust.
  • 4y ago
• thaumaturgy 4y ago
  > The precise technical details of how SWRO works are not critical to this analysis, but a summary is presented here. Yeah. This blog post spends a lot of words on the idea of large-scale desalination, but it's closer to a child's blueprint of a spaceship than even a rough proposal for a viable engineering project. The Carlsbad Desalination Plant near San Diego was completed a few years ago and is now operational. It is the largest, most technologically-advanced and energy-efficient desalination plant in the United States. It is approximately the best we can do right now for large-scale desalination. It cost about $1 billion to construct, about $50 million per year to operate, and produces about 150 acre-feet of fresh water per day. "Stage 1" from this blog post proposes to produce multiple millions of acre-feet of freshwater. All of the costs in the blog post are off by a couple orders of magnitude.
  • chrisseaton 4y ago
    > acre-feet That’s an incredibly strange unit.
    • rrss 4y ago
      It is very common for water projects. I think it comes from reservoirs, since the area is measured in acres and the depth in feet.
      • kragen 4y ago
        this particular medieval unit comes from irrigation maybe a rice crop requires three feet of water from planting to harvest, and you normally only get three inches of rain during that time, so you need 2.75 acre-feet of irrigation water per acre of rice
    • LegitShady 4y ago
      totally normal while discussing hydrology in the usa
      • kragen 4y ago
• 77pt77 4y ago
  Where's the energy coming from? Desalination takes a lot of energy.
  • rrss 4y ago
    Large-scale solar: > requires 5.6 GW of solar energy. For context, this is roughly 10 days of solar panel production in 2021, though the industry continues to grow explosively. 5.6 GW consumes roughly 112 square km of land
    • 77pt77 4y ago
      How does this compare to just planting trees? No maintenance and they also sequester carbon. All this seems to me like replacing trees with silicon and maybe that doesn't make sense.
      • kragen 4y ago
        photosynthesis is about 3% efficient the most popular solar panels are about 21% efficient solar panels don't require maintenance, though efficiency drops if they get dusty trees commonly require a lot of maintenance, i guess you don't know any gardeners; most afforestation and reforestation projects totally fail because they neglect this but the biggest issue is that trees generally don't desalinate seawater mangroves sort of do, but their output is water vapor, and generally growing mangroves in ocean water decreases evaporation from that ocean water rather than increasing it in summary, how pv-powered desalination compares to just planting trees is that pv-powered desalination produces fresh water and planting trees doesn't
• Aloisius 4y ago
  Why would you pump desalinated water upstream instead of gray water? Not that it makes much sense anyway to pump water uphill because people want to farm in places that can’t support it.
• m_dupont 4y ago
  He's completely neglected the energy costs of pumping all that water uphill, which I think may be significant. If we take that 876 million cubic metres of water from his example and pump it to, say, lake mead (also in his example), the total change in gravtiatonal energy is m = 876 10^6 m3 water = 876 10^9 kg g = 9.81 h = 375m lake mead mgh = 3.22 10^ 15 J = 895 GWh If my calculations are correct, the energy cost of pumping the water exceeds the cost of desalination by far. Now obviously IRL all that water wouldn't go to lake mead but a back of the envelope calculation shows that the water pumping costs shouldn’t be ignored. It would probably be better to use desal for providing coastal cities with 100% of their water and simply reducing the amount that we pull out of the rivers in the first place
  • thehappypm 4y ago
    The article includes pumping costs
    • m_dupont 4y ago
      I reread the article just then and while he does indeed mention that pumping can be done "easily" he never calculates the energy cost associated with it. In the 5th paragraph of the section titled "what?" He says that "even including pumping and 25% solar utilization, just 20,000 acres of solar panels ... would be adequate to power 100% of arizonas imported water", but he doesn't actually derive that figure. He doesnt calculate the pumping costs. So yes, I think its fair to say that he neglected pumping costs
  • stevep98 4y ago
    You’d recover some of the energy as it passes through the Hoover dam. In fact this proposal has the side benefit of storing energy from solar.
• carapace 4y ago
  There's this kid who figured out a solid state device that boils water to steam when the sun shines on it. (It's a flat, thin layer of a black foam-like material.) I'll try to dig up a link... Anyway, you could mass produce these and float them in the ocean. The idea is that they would add moisture to the atmosphere which then carries it inland, rains, etc... I have no idea if it would work.
  • aliswe 4y ago
    sea water already evaporates readily, though. its part of the water cycle!
    • carapace 4y ago
      Yah, that's why I think this might be a good idea (or at least not as terrible as some other ideas): it's just turning up the knob a little bit on a process that's already occurring naturally.
• ciconia 4y ago
  Desalinating sea water in order to replenish the sweet water reserves we ourselves have degraded with unsustainable practices is pure madness. What needs to be done instead is to stop interfering with the water cycle [0], let rain water infiltrate the ground, recharge aquifers and restore soil moisture. In order to do that we need to stop the habit of making the ground impermeable (with cement and tar), and stop sending rain water to the sewers to be thrown back to the ocean, and then plant trees. Lots and lots of trees. [0] https://en.wikipedia.org/wiki/Water_cycle https://en.wikipedia.org/wiki/Water_cycle
• aaron695 4y ago
• Euphorbium 4y ago
  This is so hilariously ridiculous, that capturing an icy asteroid and melting it in the grand canyon seems more likely.
• thehappypm 4y ago
  It seems unrealistic to this in a state like Arizona, but plausible for a place like California. The central valley is not substantially uphill, nor is Napa, nor are the cities. California cuttings its colorado river usage by half would be amazing, and desal is a way to get there
• boxed 4y ago
  American units are hilarious. "acre-feet of water" is just the weirdest thing I've read in years.
  • ergvgdvgrd 4y ago
    It's incredibly intuitive. An adult soccer field is 1.8 acres and a foot is... the size of a man's foot. I can visualize this volume. Meanwhile, an acre foot is 1283 m^3. I don't have intuition for that volume measurement.
• elmolino89 4y ago
  In many areas planting new trees without a stable source of already scarce water may be pointless. So, yes, desalination on a large scale will sooner or later would be necessary. At the same time idea of "provide more water, skip the water use regulation" is quite mad. Growing alfa-alfa in CA to be shipped to Saudi Arabia is brain dead even if apparently commercially profitable. It should not be.
• LatteLazy 4y ago
  Why not just recycle the water people already used? Making sewer water drinkable is much cheaper and easier than desalinating it. And very very little water is actually "used" (chemically turned into other molecules...).
  • pvaldes 4y ago
    > Making sewer water drinkable Or even better edible. Is called a garden.
    • LatteLazy 4y ago
      Exactly. People come up with these weird "figures" like it takes "12l of water to make an almond". That doesn't mean 12l of water is squeezed into one incredibly dense almond. It means 99.99% of that water evaporates and rains back or returns to ground water or whatever and needs treating again before it can go back into someones tap...
• nuc1e0n 4y ago
  This is bloody obvious. Why is this desalination not being done already?
  • pvaldes 4y ago
    It was much more expensive than plants. And you end with a lot of salt, that you can't just dump in the soil or the coastal areas without some bad outcomes
  • timbit42 4y ago
    There are 16,000 desalination plants around the world. Source: Zero Energy Cost Fresh Water: https://youtu.be/M5RG13AG4Bo?t=46 https://youtu.be/M5RG13AG4Bo?t=46
• ankaAr 4y ago
  We are loosing our glaciers that store water and feed our rivers. We don't need to refill the rivers with sea water, we need to cut down carbon emissions or we will always putting a band aid over the really big problem we have.
  • drpyser22 4y ago
    Do you know for a fact that cutting carbon emissions will bring more rain to those places that are drying up? How quickly? How much time will it take between everyone getting reasonable and stopping carbon emissions, and climate actually turning around in our favor? Its too late for warning about carbon emissions. Sure, we need to address it to not worsen future issues, but it's not going to solve our current and impending problems. Am i mistaken?
• pencilguin 4y ago
  Instead of siting polar panels in the desert, it would be overwhelmingly more efficient use of resources to float the solar panels on the canals and reservoirs involved, cutting evaporation and bio-fouling while keeping the panels cool for better efficiency and longevity, and also more easily cleaned of dust. California has begun experimenting with PV on canals, while in India it is already in full production. So, panel area is moot. Brine may be returned to the sea via a long leaky hose, eliminating effects of excess salt concentration on wildlife by distribution along its length. There is no need to produce extremely concentrated brine, anyway: there is plenty of seawater, and it takes less energy to extract fresh water from less-concentrated brine. You don’t need expensive PV and reverse osmosis to separate fresh water from brine: greenhouses can do the job at much less capital cost, with incoming water used to cool the glass that fresh water will condense onto the bottom of, and heat exchanged from outgoing brine to incoming brine after it drains off the condenser and spreads out over black evaporation pans. In some places, condensing the fresh water is unnecessary; the water vapor may be released for the wind to carry off, to rain out into mountain streams collected behind alpine dams. North/central California is ideally situated for this mode, with myriad dams in long use in the Sierra Nevada range. Hawaii successfully demonstrated using deep sea water solely as a coolant to condense fresh water directly from ambient humidity.