Remember, the alternative I'm comparing it to is restoring the land to a forested state (specifically one with much higher food production).
>draining much of the run off into large basins
…from which it evaporates, leaving the salt. Not a great plan.
You have to design for the desert: evaporation > rainfall. That means getting the water shaded asap. Further, run-off is not a given. It's better to design for in-place infiltration instead of run-off by remediating hardpan, imprinting, contour earthworks, etc.
>water ingress likely far outpaces whatever could be pumped out of the ground
Remember, the alternative I'm comparing it to is restoring the land to a forested state
You do both, the two activities feed into each other, the greenhouses increase air moisture down wind and help you get plants growing, which feeds back into getting more rainfall once you get a large enough area going.
You have to design for the desert: evaporation > rainfall. That means getting the water shaded asap.
> Remember, the alternative I'm comparing it to is restoring the land to a forested state (specifically one with much higher food production).
I'm puzzled. If the land is forested, it's no longer usable for crops in the sense that land occupied by trees cannot simultaneously be occupied with something else. So, even if you interspersed crops among the trees somehow, you're not going to have higher food production than fields that consist of nothing but food crops.
> …from which it evaporates, leaving the salt. Not a great plan.
I see you're cherry picking my comments without full context. Although I can't remember specifically why I mentioned drainage basins. I suspect it was because of run-off storage. See below.
Anyway, the point of solar desalinization (or rather, any desalinization) is to, well, evaporate or separate the water to separate salt and other unwanted things in solution, so unless you're willing to accept that desalinization is going to yield dissolved salts, then there's no point in doing it, is there? The salt doesn't magically disappear.
I also suspect that you may not live in a climate like I do, which is largely classified as a high desert, mountainous region. You don't have to design for run-off. Run-off is a given. An inch or less of rain leads to heavy flooding of lower areas simply because the soil isn't conducive to drainage or absorption of precipitation, and the steep canyons upstream serve to collect and concentrate rainfall. So, you wind up with low-lying areas that fill up with brine collected upstream from various salts and minerals, and eventually settle in subterranean aquifers that are entirely non-potable without desalinization. The drainage basins already exist. Oftentimes, salt lakes appear and persist for weeks following a rain because the atmospheric humidity is too high to allow for quick evaporation. The upshot is that if you were using a solar greenhouse, you wouldn't have to pump the water particularly far. Or you could pump it out of the ground.
> The Ogallala aquifer is currently pumped 6x faster than it's being recharged,
I wasn't talking about potable water. I was humoring the "seawater greenhouse" as a method of treating non-potable water, pumped from underground briny aquifers. I think you have this idea in mind that all subterranean water deposits are fresh water. They're not.
Remember, the alternative I'm comparing it to is restoring the land to a forested state (specifically one with much higher food production).
>draining much of the run off into large basins
…from which it evaporates, leaving the salt. Not a great plan.
You have to design for the desert: evaporation > rainfall. That means getting the water shaded asap. Further, run-off is not a given. It's better to design for in-place infiltration instead of run-off by remediating hardpan, imprinting, contour earthworks, etc.
>water ingress likely far outpaces whatever could be pumped out of the ground
The Ogallala aquifer is currently pumped 6x faster than it's being recharged, and that's not even a desert yet. http://www.upi.com/Science_News/Blog/2013/08/28/Ogallala-Aqu...