Not quite sure how to phrase this, but wondering:
Is it possible to take a desert area and turn it into a lush, green environment?
I am thinking of pumping ocean water that has been treated into fresh water and start a series of vegetation that would thrive without much, if any, man-made tending.
For instance, if we converted salt water into fresh water, creating a waterway through some desert, would it eventually grow into a green, lush environment with little or no effort other than the original planting that might be needed to get it started?
I am not talking about areas like Las Vegas that has homes with trees and vegetation dependent upon homeowners paying their water bill and would die if everyone left town.
I am thinking more along the lines of creating a large river, with several tributaries, that would be left to run through a barren landscape unattended after some original planting of whatever vegetation would initially be best suited to grow. Would it eventually take hold and become green without any further effort, other than making sure those rivers didn’t dry up?
Has this ever been attempted, or are there any plans to ever attempt to do something like this? Would it even work?
If you created a river running through a desert, yes, vegetation would be able to take hold along the water course and sustain itself wherever there was enough water in the soil. Of course, they would have to be appropriate species for the environment. Natural permanent watercourses in desert areas are often lined with riparian vegetation.
This said, I would not consider such a situation “self-sustaining.” This will require a considerable input of energy to desalinate the water and pump it. Without this constant input, the system will fail in pretty short order.
Desertification can be effected by stripping an area of its plant cover, removing shade, wind protection and much of the soil’s capacity for retaining water. So why shouldn’t it be possibly, in principle, to plant a sufficiently large area, initially support vegetation by artificial irrigation, then when the soil and ecology has been rehabilitated to very gradually withdraw irrigation (which of course will mean the ecology will change, but not again to desert)?
You should check out Ma’ammar al-Qaddafi’s Libyan Great Manmade River Project. The project, which is intended to drain the fossil Nubian Sandstone Aquifer System under the Sahara Desert to provide drinking and irrigation to the northern (mostly coastal) regions of Libya. An exact public accounting of the project doesn’t exist for obvious reasons, but some estimates place it as high as US$40B in 2010 dollars. Losses from leakage are significant; by some estimates more than 70% of the water is lost between the pumping stations and the destination, and all of this to provide drinking water and grow a small amount of high value crops; the system is by no accounting cost-effective or self-sustaining by any reasonable definition of the word.
Realize the deserts are themselves self-sustaining and often quite delicate habitats in which the flora and fauna have undergone substantial adaptation to survive in an arid climate. Flooding such an area with water and turning it into cropland will destroy such an ecosystem, which should not only be a horror to treee-hugging ecologists but also of concern to more pragmatic conservationists who appreciate the unintended downstream effects of radical ecological change.
However, there is really no reason to do this. The planet is not bereft of arable land, as evidenced by former agricultural fields being converted to tract housing. What is lacking is growing space in many overpopulated developing nations that have not substantially converted to an industrial economic base (Pakistan is an example) or good utilization of arable land in regions with sustainable irrigable water sources. The real issue is access to fresh irrigable and potable water; as much as 70% of the worlds crops are grown using non-sustainable water sources, or water sources that are being contaminated by overuse or use as an industrial waste solvent/carriage. There is almost no reason to convert desert areas to agricultural land on a sustainment basis except due to politics and market.
My first thought on reading the OP was that you could build a canal to flood the Qattara Depression. It would be salt water, not fresh, but would still support an ecology. That was an idea I first had back in, oh, probably middle school.
Yeah sure it can be done just with a lot of energy. I mean just put enough water somewhere a bunch of seeds animals you can create an environment. A lot easier then thermoforming.
I was actually thinking about starting a thread on this, after reading Jared Diamond’s “Collapse” last week.
My thought was - mountains generate rainfall, right? The prevailing wind comes along at ground level, and then as it hits the hills is forced upwards, leading to sudden cooling and precipitating the water out (it’s been a while since school geography…)
So - build a whacking great mountain in the desert. Use sand as the basis, then a layer or two of concrete for stability, terrace it and fill it up with nutrient-full dirt. Then leave it alone and see what happens.
I’m thinking if you try for a hill, say 1,000m tall and 1,000 metres or so round the base you’re bound to get an effect of some sort. Of course, the labour involved in creating such an object is huge - but then you have no ongoing costs, apart from regular inspection/monitoring.
One of Diamond’s theses in “Collapse” is that, sure, we’ve got enough arable land now, but it’s being degraded through deforestation and soil erosion. Anyone knowledgeable care to comment on that? And also, of course, if population projections for the next 50 years or so are accurate, we will eventually need enough arable land for 12 billion people, not just 6 billion, so being able to turn desert into more human-friendly landscape would certainly be a useful skill.
As you can see, except at the delta, the area that the river turns green isn’t all that wide, and I’m pretty sure most of that is not natural but rather the result of irrigation. So you would likely need several rivers or at least a large number of tributaries to get more than just a “line” of green. Or I suppose, you could make the whole thing delta-like, but I’m not sure how you’d go about doing that.
Done on a micro scale, it’s called permaculture. Gaia’s Garden, by Toby Hemenway (cited in the “further reading” list in the link) is an excellent introduction.
Desert rivers have splendid pockets of vegetation but a lot of that is dependent on silt being washed down from other upland areas, so you’d need a constant source of soil or silt (for starters).
You’d have to pump the water up to wherever you wanted the tributaries to start. That’s going to cost you, not to mention the desalinization of it all.
So if you can desalinate enough water, pump it into high enough elevations, and feed enough silt into the system to sustain more than tamarack and bullrushes
then that’s a good start.
There are plenty of little desert mountain ranges that can be downright lush at higher elevations (the La Sals in Utah for instance) but the amount of water that ultimately comes out of them is barely adequate for a couple of fishing creeks and maybe a bit of irrigation. You’d have to build a helluva mountain to generate enough water.just for a small farming community.
is it more “self sustaining” to have water flow in an open “river” rather than a closed “pipe”? E.g. Southern California is fed by a “pipe” taking water from far away mountains. But in scale it is quite comparable to a natural “river”.
The only replenishable water available at this point is the one we see in the rivers. There also lakes, but if there is any “extra” water in a lake, it would flow out as a “river”. Now, in some cases you could argue that river water is not being fully utilized. E.g. the construction of Aswan dam led to big increase of arable land in Egypt, and previously for centuries there were more minor increases through irrigation schemes. But the amount of water in the Nile does not change, so unless you figure out a way to significantly reduce water consumption per acre eventually you would end up spending all the river water before it reaches the sea and the expansion of irrigated acreage will end. One of the reasons for the drying up of the Aral sea was precisely that - the two rivers that feed it got pretty much fully spent on irrigation before reaching the lake.
You might get your rainfall as you wish, but don’t you think that weather/climate is likely to be affected somewhere else, perhaps adversely? That rain won’t be going where it used to. Perhaps somewhere downwind you will be creating a desert from a rainforest.
