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Depends on where you live. Cape Town, for example, has been experiencing frequent and prolonged droughts recently. Parts of India like Chennai are also having s

Depends on where you live. Cape Town, for example, has been experiencing frequent and prolonged droughts recently. Parts of India like Chennai are also having serious problems. And so on. California also isn't a great example, because it is regularly criticized for selling water rights far too cheaply at times when the state has been suffering from drought; I think "Nestle" and "almond farms" are the usual culprits.

tzs 7y ago
I'm not convinced about almond farms. Yes, I've seen the claim that it takes 1.1 gallons of water to grow one almond. But 1.1 gallons of water has about 3500 times the mass of 1 almond, so almost none of that 1.1 gallons is actually in the almond when it is exported from California. So how much water is actually consumed to produce that one almond, and how much remains available to go on to be used to produce more almonds or other crops?
- idoh 7y ago
  Almonds come from a tree, the tree requires the water to grow the almonds. The tree draws water from the ground, then there is transpiration where the water moves through the tree and out, like through the leaves. None remains, all the water goes into the air.
  - tzs 7y ago
    Are drip or micro-irrigation systems so precise that most of what they put into the ground ends up in the plant? Also, what happens to that water that ends up in the air? California winds are mostly from the west or northwest. I'd expect a lot of what goes into the air to come out as rain or snow on the windward side of the Sierra Nevada mountains, which is the same side the almond growing regions are on.
    - idoh 7y ago
      With the water, there is transpiration, which is the water that flows through the plant, evaporation, which is water that goes from the ground to the air directly, and then when the water goes into the water table. With drip irrigation, you get less loss to the water table and to evaporation, but it doesn't impact transpiration. For water that winds up the air, no idea there. I'd guess that irrigation would have no impact to down wind precipitation in a given area.
eesmith 7y ago
Sure. I just want to know how the cost savings from water alone can be enough to pay for switching to aeroponics. I agree the Central Valley water price is artificially low. https://www.mercurynews.com/2018/01/29/california-water-desalination-projects-move-forward-with-new-state-funding/ https://www.mercurynews.com/2018/01/29/california-water-desa... gives desal water prices, which sets an upper-bound: "Ocean desalination costs between $2,000 and $2,500 an acre-foot, Mills noted. Brackish desalination can range from $1,000 to $2,000." Let's say the true price of water is $2,000 per acre-foot. The link says that 3 acre-feet are needed, so $6,000 per year. Let's say that aeroponics is 10x more productive than farmland (pulling that number out of my ass), and that no water is needed (obviously false). Can I buy aeroponics equipment to cover 4,300 sq.ft/400 sq.m for an amortized yearly cost of $6000? I tried to find more concrete numbers, but failed. Hence why I'm asking how it can work out.

tzs 7y ago

I'm not convinced about almond farms. Yes, I've seen the claim that it takes 1.1 gallons of water to grow one almond. But 1.1 gallons of water has about 3500 times the mass of 1 almond, so almost none of that 1.1 gallons is actually in the almond when it is exported from California. So how much water is actually consumed to produce that one almond, and how much remains available to go on to be used to produce more almonds or other crops?

idoh 7y ago
Almonds come from a tree, the tree requires the water to grow the almonds. The tree draws water from the ground, then there is transpiration where the water moves through the tree and out, like through the leaves. None remains, all the water goes into the air.
- tzs 7y ago
  Are drip or micro-irrigation systems so precise that most of what they put into the ground ends up in the plant? Also, what happens to that water that ends up in the air? California winds are mostly from the west or northwest. I'd expect a lot of what goes into the air to come out as rain or snow on the windward side of the Sierra Nevada mountains, which is the same side the almond growing regions are on.
  - idoh 7y ago
    With the water, there is transpiration, which is the water that flows through the plant, evaporation, which is water that goes from the ground to the air directly, and then when the water goes into the water table. With drip irrigation, you get less loss to the water table and to evaporation, but it doesn't impact transpiration. For water that winds up the air, no idea there. I'd guess that irrigation would have no impact to down wind precipitation in a given area.

eesmith 7y ago

Sure. I just want to know how the cost savings from water alone can be enough to pay for switching to aeroponics. I agree the Central Valley water price is artificially low. https://www.mercurynews.com/2018/01/29/california-water-desalination-projects-move-forward-with-new-state-funding/ https://www.mercurynews.com/2018/01/29/california-water-desa... gives desal water prices, which sets an upper-bound: "Ocean desalination costs between $2,000 and $2,500 an acre-foot, Mills noted. Brackish desalination can range from $1,000 to $2,000." Let's say the true price of water is $2,000 per acre-foot. The link says that 3 acre-feet are needed, so $6,000 per year. Let's say that aeroponics is 10x more productive than farmland (pulling that number out of my ass), and that no water is needed (obviously false). Can I buy aeroponics equipment to cover 4,300 sq.ft/400 sq.m for an amortized yearly cost of $6000? I tried to find more concrete numbers, but failed. Hence why I'm asking how it can work out.