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How a Solar Revolution in Farming Is Depleting Groundwater

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Re: How a Solar Revolution in Farming Is Depleting Groundwater

#21

Post by Jedd »

The margins are doubtless so narrow that it's not feasible, but pumping during the day into a storage tank, and irrigating at night (while evaporation is relatively low) would be a way to slightly improve soil (though not aquifer) recharge.

Certainly it would require less water volume, but again, the infrastructure costs for panels + submersible + storage are probably untenable in precisely the places this is needed most (and where the impacts of depleting the water table will hit the most).

Re: How a Solar Revolution in Farming Is Depleting Groundwater

#23

Post by photochemsyn »

Ancient subterranean water aquifers are not a sustainable resource in the long run unless a recharge program is implemented that puts as much water into the system on a yearly basis as is withdrawn.

See the Ogallala Aquifer under the Midwest:

https://www.kcur.org/2023-04-04/with-the-ogallala-aquifer-dr...

The power source for the pumps is sort of irrelevant to the question, it could be fossil fuels, nuclear, solar or wind and the end result of uncontrolled extraction is always going to be exhaustion of the resource.

Re: How a Solar Revolution in Farming Is Depleting Groundwater

#24

Post by Jedd »

throwaway5959 wrote: post #2

How is this a solar problem? The article clearly states there’s diesel pumps as well that do the same thing.

In addition to the ways described in sibling responses to this question - diesel pumps suck, solar (submersible) pumps push.

In practice you can't suck more than about 8 metres (in theory it's a bit more), and while there are ways you can force a ground-based pump to get water up from a deeper depth than that .. the economics work against you.

A submersible pump - DC-driven by solar typically - can sit at the bottom of your bore, and push 100 metres or more upwards. No sucking required, so they're relatively simple and efficient.

(My little 75mm x 500mm submersible solar pump, for example, is pushing about 5k litres per day through 600 metres of 50mm pipe, with a vertical (head) of ~40 metres from bore water level.)

Re: How a Solar Revolution in Farming Is Depleting Groundwater

#25

Post by contravariant »

schneems wrote: post #13

I’m very naive in this space. What percent of water extracted makes its way back into the water table and how long does it take? I assume you lose some to the plant that is harvested and some to evaporation. But how much makes it back?

I'd see what the Dutch water suppliers have to say about it, pumping up ground water and managing the water table is kind of their thing.

Re: How a Solar Revolution in Farming Is Depleting Groundwater

#26

Post by peterleiser »

Jedd wrote: post #21

The margins are doubtless so narrow that it's not feasible, but pumping during the day into a storage tank, and irrigating at night (while evaporation is relatively low) would be a way to slightly improve soil (though not aquifer) recharge. Certainly it would require less water volume , but again, the infrastructure costs for panels + submersible + storage are probably untenable in precisely the places this is needed…

If you don't irrigate during the day in hot climates some crops will die, and the yields will be terrible for most.

Re: How a Solar Revolution in Farming Is Depleting Groundwater

#27

Post by ramraj07 »

schneems wrote: post #13

I’m very naive in this space. What percent of water extracted makes its way back into the water table and how long does it take? I assume you lose some to the plant that is harvested and some to evaporation. But how much makes it back?

Each aquifer is differen: some recharge quite fast with two rain seasons. Others take thousands of years.

Re: How a Solar Revolution in Farming Is Depleting Groundwater

#28

Post by westurner »

schneems wrote: post #13

I’m very naive in this space. What percent of water extracted makes its way back into the water table and how long does it take? I assume you lose some to the plant that is harvested and some to evaporation. But how much makes it back?

What are some solutions for water table depletion and how comparably sustainable are they?

How much water is extracted from air by PV panels that output H2O, and what are the impacts?

Do drilling and fracking consume lots of water and create holes through aquifers? Do holes in aquifers cause aquifers to drain out to lower chambers of the earth?

Historically, people have moved to where the water is.

Is there a subsurface ocean on Earth or Mars?

Is there enough of a thermal gradient between very deep wells and surface water to generate energy?

How many humans operating humanoid robots operating construction equipment does to take to build irrigation canals?

Perhaps helpful new solar distillation tech for #Goal6 #CleanWater:

- "Desalination system could produce freshwater that is cheaper than tap water" (2023) : "Extreme salt-resisting multistage solar distilation with thermohaline convection" (2023) https://news.ycombinator.com/item?id=39507692

Perhaps there are already sustainable salt-tolerant plants without GM; algae, kelp, sargassum

There is plenty of salt water on Earth. Does life on earth depend upon and/or derive from ocean thermohaline cycles?

Re: How a Solar Revolution in Farming Is Depleting Groundwater

#30

Post by clooper »

khaki54 wrote: post #22

[flagged]

Do you work on a farm or do you just consume their output? Degrowth is obviously not the only option but if you have never worked on an industrial scale farm then you should do some more research before casting blame on people who are trying to educate you about the scale of the problem facing us. Resources necessary for intensive industrial farming are running out. Business as usual is not sustainable regardless of how upset that makes you.
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