The unfortunate thing is that large stretches of California desert (and much of the Central Valley to the north) used to be lake bottoms and have incredibly rich and fertile soils. Between that and a long growing season that's nearly cloudless, you get ideal growing conditions -- rich soil, lots of sun, low moisture (i.e. low disease load), and H2A labor -- provided you can control the irrigation. Ah the problems caused by mispriced externalities...
Most of the water that goes to farms in the Central Valley does not come from the Colorado river. It comes the Sierra and Owens Valley. The farm lands that would be impacted by this are in Imperial County.
Whatever trickle of water left over as it passed through imperial valley ends up in the armpit of Baja California where there is a lot of agriculture (which probably ends up in the US). I wonder how is Baja California going to react to this much needed plan for the Colorado river’s supply
> I wonder how is Baja California going to react to this much needed plan for the Colorado river’s supply
This doesn't affect what the US is obligated to deliver to Mexico, so so (other than perhaps feeling slightly more confident that they will get their water) probably not much at all
Yep, you're right. Only meant to associate them in terms of why they're valued land, but yes, they're in separate riparian zones. Central valley is Sacramento/San Joaquin river delta.
You can grow things in an arid region (desertification has more to do with being unable to retain water in poor soil). Whether those things are what people want to buy at the market is something else.
There are many design patterns and practices for better water management. Some of them are only just being implemented — California is now just starting to credit growers with putting water back into aquifers during seasons of excess rain (and mitigates flood risks). But there are a lot more to be done, including water harvesting structures that slow down water (converting surface water to ground water).
this is not the first time recently i've heard about how part of the solution is slowing water to return some to the aquifer but it's essential to understand that changing the rate of flow of water also changes sediment deposition rates, which can have enormous impacts on ecosystems, power production, agriculture, and a bunch of other things. It isn't a dial you get to just arbitrarily tweak.
The best example of “slowing down water” would be what beavers do. The results are not so straightforward, even with taking deposition as an outcome. Beavers following their instincts result in complex yet resilient landscapes that supports woodlands.
I think the pattern of simplification you are talking about is thoroughly explored in James C Scott’s Seeing Like a State, where complex systems are too complex for the governing body, and made legible through oversimplification. Actions are undertaken on the basis of the oversimplication. The results are disastrous. There are many historical examples. I was not talking about “slowing down water” in that way, though I get people might take it that way.
In areas with poor soil, increased deposition is a desirable thing in many cases. Extreme cases like wasteland and erosion that exposes bare bedrock, you need all the deposition you can get (until the land can support an ecosystem again)
More importantly, the design patterns I am thinking of involves the accumulation of organic material. The overall goal and metrics isn’t just slowing down water, but rather, restoring soil health to support an ecosystem, which in turn, helps regulate water.
You wouldn’t necessarily slow down the river. You start with slowing things down onsite where the land receives rainfall. And you definitely want to avoid having soil wash away to be deposited downstream.
Every site is different, and requires intense observation and unique designs using working principles — that’s design principle #1 of permaculture design, “observe and interact”.
It's crazy visiting China and southeast Asia, seeing entire hill ranges terraced (in the same way that farm fields would be divided in the UK or US), and realizing just how old those terraces are.
Makes you appreciate how old of a technology farming is.
Andrew Millison has a great video about designing with slope. This includes a brief discussion about the steep slope found in the rice terraces of Southern China
This is very much true in NM where I live. Agriculture accounts for 79% of yearly water use. We're known for our chile (63,000 tons) but that's dwarfed by alfalfa (784,000 tons).
I'm not sure what the answer is. The farmers have their own water rights, and as a group are pretty well politically connected.
We could try Eminent Domain or unilaterally breaking those old water contracts... but that's guaranteed to make the Supreme Court. Given the current make up of the SC, I don't see any decision coming that might curtail property rights. I'm guessing it'll be perpetual subsidies for letting land go fallow.
It's pretty simple, put small, but yearly growing taxes on "stupid to grow in the desert" crops like alfalfa. Slow enough to make the transition away from them reasonable for the farmers, but high enough to pressure them into no longer producing the crops.
San Diego is already has a desalination plant and Santa Barbara is about to turn on their own. However, it’s still not enough. Building desalination plants takes a lot of capital and time. Unfortunately, leverage is no longer cheap and the economy is about to suffer a deeper downturn
Also, people especially farmers have been complaining about San Diego’s pricing to pay for their plant. Still, like you I don’t see any other long term solution since CA provides 1/3 of the US food supply. Maybe stop exporting live stock feed grown from the desert (ie water) to Asia?
I know its a bit of a pipe dream, but why not raise taxes and pass a 1930s style infrastructure spending bill to compensate? Would help with the downturn that feels like it'll happen at any point (in earnest, for better or worse) by providing good jobs and solving problems all at the same time?
We could do this with desalination, green energy projects, and other public infrastructure. I'd even love to see us subsidize fiber to homes and businesses en masse and allow ISPs to share the resulting infrastructure like they do in Europe
Desalination isn’t cost prohibitive to build, it unfortunately costs an absurd amount of money to run at the scale farmers use water. And then you’re faced with trying to pump that water upstream to users.
The basic issue is farmers can only make money with practically free water they get from natural sources. Anything that raise the average price per gallon is useless to them and they own most water rights. The long term solution is to reduce the amount of farming via eminent domain and rejecting all new farming operations.
I was considering cities first with this, which I realize isn't the biggest use of this water but is part of it.
I also imagine with continued investment and research the tech could get better at scale too. It may be hard today but perhaps there's headroom for innovation with more funding while tackling migrating cities to using desalination
Raising taxes is not a good idea when many businesses and individuals have already left CA due to high taxes and a high cost of living. That said that also seems to be the only solution to a neglected problem, which can no longer be ignored. Someone can prove me wrong, but there doesn't seem to any good choices left.
Much of the Imperial Valley — which uses a lot of Colorado water — is below sea level and could (in theory) be fed by desalinated water with very little pumping. But it's not economically viable. Still, quite a bit more viable than nuclear greenhouses!
Is desalinating enough water to irrigate an entire valley less viable than nuclear greenhouses? I'm not so sure. Both would be extraordinarily expensive
desalination cost varies, but for the London desalination plant it's £1.6 per litre[1]. I am sure that's on the higher end, but let's just work through the math.
1 mm of rain on 1 ha of land is 10 000 litres or 10 cubic meters of water. So to replace 1mm of rain in Britain, costs £16. Average annual rainfall in UK ~1150 mm. So if you had to replace the entirety of it from desalination, you would spend like £18,400.
If you are growing wheat, you get like 8 or 9 tons per hectare and you sell if for like £230 per tonne (these are very rough numbers) so your total revenue is like £2,000 per hectare. Out of that, your profit margin is probably under 10%
So you will be loosing money you have to replace more than a couple of % of annual rainfall from desalination, and if you grew wheat with entirely desalinated water it would cost 10X as much as 'normal' wheat does.
Now, typically you only irrigate high value crops, and wheat is a low value crop. Also you probably don't need the entire annual rainfall, and there might be cheaper desalination elsewhere. You can re-do the math with other crops and other desalination costs.
But fundamentally price of desalinated water is too high for use in agriculture.
Not at market energy prices, that's for sure. One possible exception would be if you coupled the desalination system to a solar farm and you only ran it at midday when generation exceeded demand. If you're getting the electricity "for free", it would change the calculation substantially.
I believe the environmentalists aren’t fond of desalination because you have to dump the extra super salty sludge that’s extracted back into the ocean somewhere, thus increasing salinity levels in a particular area.
This is just BS. The amount of desalinated water is completely dwarfed by normal evaporation. If we replace _all_ the water used in agriculture by desalinated water, we won't even make a dent in the global saltwater balance.
Some local effects are certainly possible, but they can be mitigated by pre-diluting the brine.
Local effects are indeed the concern. If you dump the brine in something like a harbor (typically where cities are built) you can have extreme growth in salinity which also makes desalination harder. It’s a problem for Middle Eastern countries reliant on it
In theory I'd rather not give fossil fuels any "leg up" as it where, though scientifically I appreciate where you are at with this, I certainly don't want it to have the knock off affect of encouraging more fracking
Well, not just dumped. It's diluted first. Or should be.
As I understand it, San Diego's plant dilutes the effluent by mixing it with additional ocean water, but I don't have a good handle on how well that works.
Regardless of pollutants, agriculture uses way too much water for this to be practical. Average seawater salinity is 35 g/L, and the WHO recommends a salt intake of at most 5 g/day, so from one liter of water you get enough salt for seven people for a day. Approximating global population at 7 billion people, that means we could consume the salt from about 0.365 km^3 of water per year.
Just the US alone uses about ~110 km^3 of water for irrigation per year.
The water used to irrigate crops has dissolved minerals in it. As the water is taken up by plants (or evaporated), it leaves those minerals behind. This then raises the salinity of the soil. Eventually, the soil becomes too salty/mineral encrusted to support crops. This happened in the Middle East. What is now Iraq used to be the main grain growing region of the Middle East several thousand years ago. Over time, the salt in the soil rose to the level that wheat could not grow, but barley could. Eventually, the soil became too salty for barley. Today, some of the Iraqi desert shines in sunlight because of the salt crystals. It has never recovered and will never recover. California is progressing faster.
Selenium is one of the minerals that ends up in the runoff of Californian agriculture. In some coastal areas, the selenium content is so high that bird eggs laid by wildlife never harden. Or the birth defects are so high that the hatchlings don't live.
Think about how much water a person uses per day compared to how much salt. The former is measured in liters, the latter in grams. Desalination produces far more brine than humans could ever need.
Are there any credible studies in the net effects of the added salinity vs how much water is dumped back in from rain run off, reclaimed sewage and other land based sources?
The dead sea is 10x normal ocean water salinity. If you remove most of the water from Pacific ocean water and pump the brine back in to the ocean, you are basically pumping water from the dead sea in to the Pacific creating a huge dead zone until it dilutes back to normal concentrations.
It isn't the overall salinity that is impacted but local conditions.
Even though the comparison is hard to take seriously, there is probably nothing we can do at our current societal scale to make the Pacific Ocean into the Dead Sea equivalent. Ocean acidification from all the GHG pollution, now that seems to be possible. DeSal scale is just not there and we don’t actually need THAT much extra water for cities. Agriculture could be another matter, but economics are not there yet.
Open a nuclear reactor in Canada and power greenhouses there. Desalinate some water while you’re at it.