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Earth Science

Huge Reservoir of Fresh Water Found Beneath the Sea Off Hawaii (newscientist.com) 83

A huge cache of fresh water found beneath the sea floor off the western coast of Hawaii's Big Island could lift the threat of drought for people living there. From a report, submitted by reader schwit1: Eric Attias at the University of Hawaii and his colleagues discovered the reservoir, which is contained in porous rock reaching at least 500 metres beneath the sea floor, using an imaging technique similar to an MRI scan. They used a boat towing a 40-metre-long antenna behind it to generate an electromagnetic field, sending an electric current through the sea and below the sea floor. As seawater is a better conductor than fresh water, the team could distinguish between the two. They found that the reservoir extends at least 4 kilometres from the coast and contains 3.5 cubic kilometres of fresh water. Most of Hawaii's fresh water comes from onshore aquifers, which are layers of rock and soil underground that collect water after rainfall. The team believes that this newfound reservoir is replenished by water flowing out of these aquifers.
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Huge Reservoir of Fresh Water Found Beneath the Sea Off Hawaii

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  • by PPH ( 736903 ) on Friday November 27, 2020 @02:13PM (#60770872)

    Start pumping fresh water out and see how fast salt water will enter that aquifer to replace it.

    • by I75BJC ( 4590021 )
      This happened in Florida. The first warnings of this were in the newspaper, The St. Petersburg Times, in the 1970's. That's why a lot of chlorine is used to purify the city water there.
    • by Anonymous Coward
      Just like what is happening in Florida.
      Count on Politicians/Lawyers/MBAs to fuck things up.

      They would be better off desalinating using either geothermal or small nuclear reactors with waste heat doing the desalination.

      Windbourne(moderating).
  • by AlanObject ( 3603453 ) on Friday November 27, 2020 @02:19PM (#60770892)

    When did this happen?

    The eastern part of the big island gets an average of something over 400 inches of rainfall a year. The rest of the islands are similar. Did they somehow break all their reservoirs or something?

    • by cusco ( 717999 )

      The western side of the Big Island is full of resorts and golf courses catering to the Asian market which require a LOT of fresh water. I think some of them are already producing their own drinking water, which is extremely expensive. That side is in the rain shadow, and while it's not technically desert it doesn't get a whole lot of rain and because of the porosity of the soil there is no way to retain much of it.

    • Comment removed (Score:4, Informative)

      by account_deleted ( 4530225 ) on Friday November 27, 2020 @03:05PM (#60771024)
      Comment removed based on user account deletion
    • Hawaii has porous volcanic soil.

      Reservoirs don't work well there.

      So, while they get plenty of rain overall, even a few dry weeks can lead to temporary shortages.

      • Hawaii has porous volcanic soil.

        Reservoirs don't work well there.

        They know all about reservoir liners in Hawaii, polymer geotextile ones are popular.

        The main issue with water on the Big Island seems to be distribution not over-all availability. There are 23 separate water systems for 185,000 people and the topography -- wet in some places, desert in others (rainfall shadow), and tremendous changes in elevation - makes building a unified system difficult to impossible.

  • They used a boat towing a 40-metre-long antenna behind it to generate an electromagnetic field, sending an electric current through the sea and below the sea floor. As seawater is a better conductor than fresh water, the team could distinguish between the two.

    They basically dropped a radio into a really, really big bathtub -- and didn't die. Can't wait to try this with my swimming pool.

    • by bjwest ( 14070 )
      An electromagnetic field can be generated by an antenna encased in a non-conductive casing.
    • A bathtub is about the largest container of water that will be bad for ya if you drop a 120 volt device in it. You would be okay if you were in a swimming pool.

      Think of it as a huge parallel circuit. Now don't try this at home kids!

      • by PPH ( 736903 )

        You would be okay if you were in a swimming pool.

        Google 'pool light electrocution'.

        • by tragedy ( 27079 )

          I find pool light electrocution incomprehensible. We've had fiber optics for half a century and periscopes for over a century and a half. It seems like there's absolutely zero reason to have the actual electric light underwater. All the electricals should be in a utility box above ground.

          • Just use low voltage electronics. Sealed LED modules are perfectly reasonable. Run them on 12VDC.

            • by tragedy ( 27079 )

              I went ahead and looked up some examples of pool light electrocution as suggested, a number of them happened with badly wired 12v systems. The 12v systems still need to convert AC to DC, so a badly wired system can run AC right into the pool. It just seems like it would be simpler in just about every way to not have electricals running into the pool. You wouldn't need to use special bulbs or seals/gaskets, or fish around in the pool to change the bulb. There wouldn't be electrocution worries jumping into th

  • by AmazingRuss ( 555076 ) on Friday November 27, 2020 @02:34PM (#60770928)
    ... for the islands to get build up far beyond what they could ever support without it.

    And then what?
  • Pump it out and sell it as Hawaiian Poseidon water. The cool, crisp water that smells like a fart.
  • It was a Perrier-Tanker.

  • I've seen via satellites that a huge tanker is approaching Hawaii, named "Mega Maid II".

  • Lets exploit the fresh water before the hippies find out.

  • by ruddk ( 5153113 ) on Friday November 27, 2020 @03:16PM (#60771046)

    Careful, don’t let Nestlé know.

    • Don't let Nestlé know what? What? What is it? Tell us. Tell us now! Is it something we want? Do we want it? Is it ours? It is ours, give it to us. Give it! Give it! Give it now!
  • Is energy
    and Hawaii has plenty of geothermal energy

    • by cusco ( 717999 )

      Only the big island. The others have moved off the hot spot so their volcanoes are either extinct or close to it.

  • Every time I've been there it rains every single day. Sometimes it's a brief shower, sometimes all day. Most of this just runs back into the ocean. I've driven the road to Hana on Maui and there must have been a hundred fresh water rain-fed waterfalls just on that one road. There would be no environmental impact to collecting this water.

  • The "reservoir" is porus rock. Water is trapped in it like crude oil and natural gas is trapped in shale in the USA.

    Which means they can use the same fracking techniques to fracture the rock and pump water. They estimate 1 trillion gallons of water in that rock. If you let the frackers in, they can probably recover as much as 20,000 gallons (not per hour or per day. Total, rest of the water will be contaminated with fracking fluid and sea water). Probably they lobbying effort has already begun to extract t

  • It is roughly 1 tera-gallon of water.
    That is essentially infinite for household, hotel, light industry, crop (coffee, nuts) use.
    Less so when used at the rate of 1 mega-gallon per day per golf course.

    • So for 100 golf courses that would be 10,000 days worth or 27 years... not seeing the problem here.

      • by ebvwfbw ( 864834 )

        So for 100 golf courses that would be 10,000 days worth or 27 years... not seeing the problem here.

        Then Perrier finds out that this is old water. No... fill in the blank with something. They lay claim to it all. Humm... Hawaiian restricted water in disposable plastic bottles. What could go wrong?

        • There aren't that many idiots in the world who would pay shipping costs from Hawai'i. They can't drink all 1 teragallons, one liter at a time.

          • by ebvwfbw ( 864834 )

            There aren't that many idiots in the world who would pay shipping costs from Hawai'i. They can't drink all 1 teragallons, one liter at a time.

            LOL.. That was a joke... However I wish that were true. Don't underestimate idiots. Look at how many plastic bottles of water they sell right now. For some reason especially to black people. They're scared to death to drink regular tap. It's funny. When I'm at the gym I have a stainless canteen. It's a cylinder shape. I fill it from the water fountain. I've used that container for over 10 years. When I first joined the gym I think I was the only one. Then I saw some other people doing it for a while. I thin

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