When I was a young kid, I spoke with an agricultural engineer once that came to our school and he gave a talk about his career and what he did and the things he was finding (this was in say 2007/2008)
The part I remember the most and what intrigued me is when he was talking about ground water supply. He said that it would be unwise to keep digging into ground water supply for fresh water, for agriculture or otherwise, and what we really needed desperately was a nation-wide grid (I live in the USA, for reference) of pipes similar to how oil gets pumped for hundreds or in some cases thousands of miles, to supply desalinated water from the coasts to every part of america and to use properly use desalinated water to re-hydrate American rivers and wells, otherwise we will find ourselves in a situation of hastening a cycle of pumping ground water at an unfeasible pace, which to me is suggested in this article.
Seems relevant now, and I imagine the long term sustainability of such a thing would be much higher (and less depleting).
Looks like that guy was right. I wonder how many people have been sounding this alarm over the last decade.
Large swaths of the country currently receive sufficient rainfall to meet agricultural, industrial, and municipal needs. Desalinating and pumping water from the coasts as a complete replacement solution is madness.
Any realistic solution to water scarcity will be a multi-pronged approach: improvements in water infrastructure, groundwater recharge, pollution control, water conservation, rainwater harvesting, and technology-driven gains in purification/distribution efficiency.
Uhhh, so being agriculturally productive isn’t just about having water, that’s the problem: California is one of the largest cereal crop producing places on earth for a reason, ditto for citrus, and many other fruit. Because the soil quality and climate are amazing for them. The problem is that it’s essentially a desert and farmers have for a century just been digging wells and aggressively draining the ground water while simultaneously removing the various catchments and watering inefficiently (seriously drive through the Central Valley and they’re all watering crops in the middle of the day when the temp is 100/40+.
That’s part of the problem with the various nut milks: it’s not just that they use a huge amount of water, but that unlike cows you have to grow them in specific environments - like the middle of the CA desert.
Broad sweeping statements don't do anyone justice.
We live near the westmost tip of the US and have a water management plan for the entire county. We pay into a mitigation that manages the entire watershed.
Well, I said "almost nowhere". The Sierras and Cascades (and west of there) are the exception. If you look at the US west of the 100th meridian, though, that's still "almost nowhere".
> Broad sweeping statements don't do anyone justice.
> We live near the westmost tip of the US and have a water management plan for the entire county. We pay into a mitigation that manages the entire watershed.
I live on the east coast and can't get fined for collecting rainwater. There might be something to the notion of piping water from the "wet" coast to the Midwest and potentially beyond.
How can we make this argument when rivers like the Colorado are barely a trickle by the time they reach the ocean? Even arid areas that seem fertile like the Southwest and the Central Valley are only fertile because we're diverting and pumping water unsustainably.
Because most of the US does not have this problem. The Colorado River basin does, but it's worth noting that California's allocation is very high relative to the portion of the drainage basin within the state, and most of the state's allocation (>88%) is pumped out of the basin.
Top users of California's allocation of Colorado River water are [1]:
- the Irrigation Districts of the Imperial Valley (~61%) and its northwest extension the Coachella Valley (~8%);
- the Metropolitan Water District of Southern California (~20%) [2];
- the Palo Verde Irrigation District (~8%). The Palo Verde Irrigation District is inside the Colorado River basin.
A "water grid" sounds appealing, especially given the uncertainty of climate change. But you have to consider that water is used so much by human that you need pipes on much larger scale than you need with petroleum (the water needed for agriculture dwarfs that needed for cities - it can be easier to move the farms to the water than the water to farms). And water is quite heavy given the amount being moved, so you much more energy than you need for petroleum. Just remember that to move a river across a mountain you need the more than energy of a vast series of dams on the other side - since a some proportion is lost to friction.
No, I meant that we shouldn’t be storing water at the Glen Canyon Dam, since two large shallow lakes have more surface area. And on this scale, evaporation actually matters—consider the shade balls used in California reservoirs. But for some reason, upstream folk think that if the let the water go they will never see it again. This is not the way legal allotments work. But it’s the same reason people prefer dams to underground storage, because seeing things feels reassuring, despite it being less efficient.
So much of is either for making a semi-desert region into one of the most productive agricultural lands on earth and another fraction goes on to quench the thirst of the L.A. Basin.
I guess we could cap either per person use or cap the pop in L.A.
Just to be clear, he was talking to High School students, so perhaps sacrificed a little accuracy for the sake of making a point.
I still think the general idea is sound, even if you don't take it literally on implementation
Just to address that for the sake of that dude, I didn't want it to come across the wrong way.
To address some things further down:
I do remember a specific detail, and I don't know how accurate it is, however, he did explain that (and also prefaced how theoretical it is, even at that time more so I imagine):
- If you wanted to do this right, what you would want to do is desalinate the water and pump it to existing surface basins/reservoirs first (e.g., the Colorado River Basin), and taking great care to match that water to the ecology (e.g., mineral, PH level etc) of the water you are replenishing This way you aren't forcing an entire set of infrastructure to be obsolete, but rather working with existing delivery modes to get the water where it needs to be
- In cases where this isn't feasible, your best bet would be to run some sort of infrastructure (likely pipes) to those in need. In some cases, you might even be able to simply create new reservoirs to feed population centers to create efficient delivery mechanisms. The other thing I remember him mentioning specifically is there are many delivery mechanisms (e.g natural) ones that were no longer in productive service that could be revived also (I wish I had an example for this, but I don't).
The cheapest way to do this (by the dudes estimation) would be to use nuclear power near the coasts, that rely on the salt water for cooling which gives you two advantages:
1. in theory, the water that the plants themselves could produce a by product of clean, usable water[0]
2. The nuclear power plants themselves should be able to produce the power cheaply and ecologically friendly)[1]
3. This would incentive more research into pressurized water systems for nuclear power, which in theory could yield smaller reactors which in turn are even safer as is intrinsic to their design, they may even yield ever smaller sized reactors[2][3]
Its, in a practical sense, feasible, but I think the takeaway I had back then and even now, thinking about it, was we needed to start this by 2009 to have it be up and going by 2019. Which isn't to say that we shouldn't do something now, but rather, we're still deciding what to do about it and that's crippling
People have been trying to sound the alarm for decades. Here's a picture from 1977 demonstrating how far the land in the California central valley had fallen in ~50 years.
"As a point of clarification, the sign Dr. Poland is holding says this is the change detected in BM S661. However, according to the NGS datasheet for that bench mark (PID GU0103), it was not set until 1942. I have been told by reliable sources at the USGS that the pre-1942 subsidence, back to 1925, was a linear estimate. "
This appears to be the data sheet for the bench mark used.
Which seems to conclude that the photo is possibly very wrong, they include a new updated photo at the bottom that only goes back as far as there is reliable data.
Desalinated water is expensive compared to "free" water. At current prices for desalinated water and for produce, you cannot profitably run a farm using desalinated water.
Currently, desalinated water is used in the US only in urban/suburban areas where homeowners are willing and able to pay a bit more than usual for their existing water use.
(1) The current system in the West is rights based. First person to make productive use of water gets the right to use that water forever. It's an odd system, but it's basically land-ownership for water resources. It's easy to see the flaws in the system.
(2) You have to invent a new system. It's a fun thought exercise, but there are a lot of things to consider. The environment needs water. Should a farm making productive use of water have to pay as much per unit as an urban household using it to water a lawn? Lot's of considerations. Now that you've done that, you have to get the law changes across the entire West. The entrenched interests will lobby energetically against the change. The people who would benefit probably aren't paying enough attention to care. So the change loses.
There's already a big "grid" in place in the western US: the Colorado River. A first pass solution could be to desalinate on the coast and then pump up to Lake Meade to meet all of California's use. Then upper basin states could remove more water, no longer being required to give California their 4 million acre-feet. But the amounts of energy required to do that would be insane.
Desalination usually happens on the coast. Pumping water from their to Lake Mead, to let it run down the Colorado to be pumped to LA seems really inefficient. Why not just pump it from the desalination plant to LA?
But as an overall plan, it's not so nuts (except for the energy cost, and the hundreds of miles of aqueducts that need to be built). The point about the upper states getting water out of this is a valid one, and Lake Mead supplies Arizona as well as California.
One downside to this plan: You'd kill the Grand Canyon.
Top users of California's allocation of Colorado River water are [1]:
~61% Imperial Irrigation District;
~20% Metropolitan Water District of Southern California;
~8% Palo Verde Irrigation District;
~8% Coachella Valley Water District;
Out of these, only the Palo Verde Irrigation District is inside the Colorado River basin. The Metropolitan Water District of Southern California has access to the coastline, so it can mix in desalinated water directly. It currently mixes in local water sources and water delivered from Northern California [2].
The Imperial and Coachella valleys require an interbasin transfer in either case, but despite the presence of canals and pipelines from the lower Colorado River to these sites, supplying them with additional water from the coast would require significantly less infrastructure than pumping said coastal water all the way up to Lake Mead.
Water is freaking heavy and turbulent. You will be spending ridiculous amounts of energy pumping water on just that turbulence which is basically heat.
It's much better to have mandatory water-conserving farming practices, like covering the soil to prevent evaporation. Or even better, underground water-dripping systems, like they do in Israel and other desert-like places.
Or even even better, start switching to airponics.
Im interested to know the scale of a "water grid". Is there any idea how much water we'd need to move to satisfy all our demands with desalinated water? Also, what sort of energy is needed to raise all water up from sea-level?
The average person uses 80-100gal per day. We'd need a grid that's about an order of magnitude larger than our current petroleum fuel distribution system (the average person probably uses less then 8-10gal of liquid petroleum fuel/day).
But if water is artificially cheap, there will be no incentive.
But will we learn to tax water and write everyone a cheque to cover the cost of a basic user?
Just start with gray water re-use: nothing fancy: just a 55gal drum that collects the good gray water and discards anything looking spoiled. Pumps to toilet bowl with cheap pump.
You can't keep greywater for much time (~<24 hours) without it turning to a stinking, fetid mess. It has to either be used immediately or filtered then kept sanitized (chlorinated typically).
Mostly my comment was because I saw an expensive and complicated home gray-water contraption that seemed to aim for 100% recycling of gray-water. I figured there was cost-savings to be had by aiming for a lower recovery rate.
Yes, probably needs some disinfection, but should vastly reduce the filtration load.
Farmers engineer their fields to drain excess rain water. That is part of the reason major floods happen along rivers more often than they used to. But then they need to pump water out of the ground more often to water crops. Is there a way to get the rain water to go into the ground instead? That would help with both problems.
> Farmers engineer their fields to drain excess rain water. That is part of the reason major floods happen along rivers more often than they used to.
Not everywhere. Western Kansas has water conservation districts with terraces plowed into fields. One of the reasons that reservoirs and ponds were low for so long.
This year, they are all full, due to the massive rainfall we've had.
Those are different farmers to a large extent. The farmers I know drain their fields and have no irrigation at all: I live in an area where there is typically more than enough rainfall, so it is better to endure low yield in drought years than to pay for the irrigation equipment that could help then.
Yes. Spreading basins have become popular-ish in portions of California that have concentrated rainfall in the winter but high demand in the summer.[1]
The amount of water soil can hold is fairly proportional with the amount of organic material. Blend woodchips, sawdust, compost into the top few feet of soil and it function like a moisture battery.
The St. Lawrence river discharges approx. 16,800 m^3 a second of freshwater from the Great Lakes. However re-diverting the water to areas outside the watershed are would require an international compact between the U.S. and Canada and the various sovereign Indian territories to allow for it to happen.
I can't access the study, but this news report says it doesn't examine the causes behind this. For instance, it's way cheaper to drill deeper first then going back and doing it, you generally get cleaner water, and better flow.
> The study was published Monday in the journal Nature Sustainability. The authors didn’t examine causes behind the drilling of deeper wells but said factors can include declining water levels, improving pump technologies, different permit requirements for wells that tap deep aquifers and poor water quality in shallow aquifers.
Saw this elsewhere, and someone pointed out that choliform bacterial contamination, where it exists, is worse at the top of the aquifer, so people drill deeper to get to the cleaner water.
We should really take a look at how that stuff and nitrates from fertilizer are getting down there in the first place. Either our model of aquifers is wrong in very important ways or existing wells are getting backwash problems (eg, ground water following the outside of the bore down, or negative pressure when the pump is off pulling water in through defects in the pipes)
I tried to do the math one time of figuring out the volume of water we've pulled out of all of the world's aquifers, and how that translates to sea level rise (water ends up underground or in the ocean eventually).
I'd like to see someone with better geography skills repeat that experiment.
Yes: Gravimetric measurements from GRACE have been a breakthrough. The press release referenced within your wiki citation is well worth reading in this context:
Besides in situ wells, other helpful measurement techniques are InSAR (interferometric SAR) and post-processed GPS. Both let you measure surface subsidence to better than 1cm accuracy over broad areas, mostly due to groundwater withdrawals. This subsidence (which is in the multi-meter range in parts of CA, https://www.usgs.gov/centers/ca-water-ls) is of concern in and of itself, due to disruption of infrastructure like highways and pipelines caused by subsidence.
But, subsidence is indirect as a measurement of groundwater withdrawals, because you don't know the relationship between height lost at the surface and volume withdrawn underneath. This depends on a compaction parameter which is very hard to know.
Property owners can stymie the use of wells as a groundwater monitoring tool, because it is often not in their direct interest to supply information about local groundwater depletion. For this and other reasons, it's rather hard to use well data, even in well-instrumented areas like California.
With some obvious large gaps. There are more collected by state agencies, consultants, etc. In most places there are probably more wells than you'd think.
In addition to measuring gravity from space to monitor groundwater it can be measured at the land surface, with better spatial resolution and worse accuracy. A 1x10-8 m/s^2 change in gravity is 2.4 cm of groundwater!
The part I remember the most and what intrigued me is when he was talking about ground water supply. He said that it would be unwise to keep digging into ground water supply for fresh water, for agriculture or otherwise, and what we really needed desperately was a nation-wide grid (I live in the USA, for reference) of pipes similar to how oil gets pumped for hundreds or in some cases thousands of miles, to supply desalinated water from the coasts to every part of america and to use properly use desalinated water to re-hydrate American rivers and wells, otherwise we will find ourselves in a situation of hastening a cycle of pumping ground water at an unfeasible pace, which to me is suggested in this article.
Seems relevant now, and I imagine the long term sustainability of such a thing would be much higher (and less depleting).
Looks like that guy was right. I wonder how many people have been sounding this alarm over the last decade.