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Re:The Colorado River is shrinking by ajross on Wednesday July 21, 2021 @01:31PM (#27909320)
Virtually all agricultural irrigation evaporates. It doesn't even run off into local streams (which you can verify by, heh, the lack of local streams in the Utah desert), much less seep into the ground.

Underground aquifers fill over decades and centuries, and in this environment, almost always laterally, not from seepage from rainfall. I think the demand for proof needs to go the other way, honestly. Presumptively this water is pretty clearly "wasted".

Re:The Colorado River is shrinking by D13Fd on Wednesday July 21, 2021 @01:37PM (#27909411)
I think the question is how much less water would be used with a modern irrigation system rather than flood irrigation.
Re:The Colorado River is shrinking by tfigment on Wednesday July 21, 2021 @01:48PM (#27909548)
Ostensibly you could grow hydroponically and have very little waste but order of magnitude cost increase in power needs. Every other solution falls in between I guess.
Re:The Colorado River is shrinking by ashtonkem on Wednesday July 21, 2021 @02:02PM (#27909756)
Electricity is orders of magnitude easier to move than water, and its price is dropping too.
Re:The Colorado River is shrinking by User23 on Wednesday July 21, 2021 @06:59PM (#27913235)
> Virtually all agricultural irrigation evaporates. It doesn't even run off into local streams (which you can verify by, heh, the lack of local streams in the Utah desert), much less seep into the ground.

The evaporation figures I can find range from 30% to 50%, which is hardly virtually all. I've never been to the Utah desert, but in the California desert I've dumped out water and watched it disappear into the ground. The absence of streams only indicates that seepage and evaporation together get all of the water that would otherwise flow in them.

> Underground aquifers fill over decades and centuries, and in this environment, almost always laterally, not from seepage from rainfall. I think the demand for proof needs to go the other way, honestly. Presumptively this water is pretty clearly "wasted".

Unconfined aquifers will fill as fast as rainfall can seep in, which depending on the area can be a lot less than decades.

How is letting the Colorado flow into the Pacific more of a "waste" than using that water to grow food and letting the excess seep into the water table and fall as rain on the other side of the Rockies?

Re:The Colorado River is shrinking by ajross on Thursday July 22, 2021 @10:21AM (#27919204)
Those figures are for water that doesn't enter the plants, though. All that water, except for a tiny fraction represented in the shipped output (nuts, whatever) still ends up locally in the air.

And "disappearing into the ground" is absolutely not water entering an aquifer! All you get is wet dirt. Which then... dries out. Again, this isn't how aquifers work.

There's no free lunch here. Growing plants in a desert under the open sky requires a staggering amount of water. It just does. If you want to push efficiency measures look at greenhouses.

Re:The Colorado River is shrinking by User23 on Thursday July 22, 2021 @07:50PM (#27925741)
> Again, this isn't how aquifers work.

Are you confusing confined aquifers and unconfined aquifers? That's exactly how unconfined aquifers work. Where I live the wells never go dry because every time it rains they are replenished.

Maybe the desert doesn't have unconfined aquifers and that's why you're so strident on this? I really don't know, but I'm curious so please elucidate if you can.