California's Water Crisis

[Hygro]

Desalinization plants can make a huge difference. What we need is a series of huge ones solar powered and we'll send the water up to the mountains and let it trickle back naturally

 

[Timsup2nothin]

Desalinization plants can make a huge difference. What we need is a series of huge ones solar powered and we'll send the water up to the mountains and let it trickle back naturally

We already have one of those, but it suffers from slight inconsistencies in its output so people are dissatisfied.

On a more serious note, do you see this as accurate,

Unfortunately, humans have demonstrated that no matter how much additional water source is provided to California, there will be sufficient migration to California to maintain a constant excess of demand. Ultimately, this isn't a drought problem, it is a California is apparently too attractive problem.

and do you have any ideas? I'm leaning towards 'free market water', but I think there just has to be something better.

 

[Hygro]

Well, I think the biggest problem is that farmers can crunch the aquifers so that water can never be priced well until the aquifers are permanently dry.

We need to overhaul our agriculture significantly.

I for one would be happy to see the state's population continue to grow, as long as we build up instead of out.

 

[Farm Boy]

I ignored that because it is based on the same faulty idea that water from a desalinization plant is somehow unique that the 'salting the earth' tripe was based on. If irrigation salts the Earth, it salts it equally no matter the source of the water. The idea that it would somehow not be suited for washing is just more ridiculous nonsense piled on.

Actually, unless I'm supe mistaken, which is totally possible as I'm going to be too lazy to dig around - I think well water pumped from low aquifers is actually going to wind up heavier with minerals and salts than most other waters. And I doubt that irrigation filtration systems are super rigorous. So I don't think all water is created equally when it comes to salinization effects. Are desalinization plants a supe great idea for coastal conservation? I thought I had read something about them being pretty rough on coastal wildlife, but again I could be way out of date.

 

[Timsup2nothin]

Well, I think the biggest problem is that farmers can crunch the aquifers so that water can never be priced well until the aquifers are permanently dry.

We need to overhaul our agriculture significantly.

I for one would be happy to see the state's population continue to grow, as long as we build up instead of out.

As to the farmers crunching the aquifers, I see that as an aggregate problem. Collective demand exceeds collective supply. While agricultural demand is huge, and can be seen as grossly inefficient, it isn't like anyone is advocating for increasing it. The farmers wasting water are wasting it under the same water rights it has always been wasted under.

Despite the 'corporate robbers as evildoers' attraction, agribusiness can't just pack up and move on. Orchards don't ship. Vineyards don't ship. Moving somewhere else and expecting the illegal immigrants to follow them to do the work seems sketchy. And as we all know, happy cows don't stand around in snow up to their ears. So expecting agricultural demand to decline in order to compensate for rising other demands is not viable.

So we're back at that other rising demand. Five miles from me there is another three square miles of desert being converted to streets and houses and lawns. They will be sold with "Drought? What drought?" as an integral part of the pitch. The people buying the houses are not going to pack up and leave any more than the agribusiness guys are, because they won't be any more able to do so.

The developer; they will pack up and leave, eventually.

I could say I would be happy to see the population grow, as long as the growth is in worshipers of the mighty Tim, but that won't make it happen. There is no indication that growing up instead of out is going to happen either, without some application of incentive. Any ideas there?

 

[Timsup2nothin]

Actually, unless I'm supe mistaken, which is totally possible as I'm going to be too lazy to dig around - I think well water pumped from low aquifers is actually going to wind up heavier with minerals and salts than most other waters. And I doubt that irrigation filtration systems are super rigorous. So I don't think all water is created equally when it comes to salinization effects. Are desalinization plants a supe great idea for coastal conservation? I thought I had read something about them being pretty rough on coastal wildlife, but again I could be way out of date.

I'm guessing that you are spot on...in all probability desalinization plant output being put into the water mix would make the water better, not worse.

As to effects on coastal wildlife, I have no real clue but it would be surprising beyond belief if a desalinization plant was good for them, wouldn't it?

 

[El_Machinae]

Historically, water rights were assigned differently between the eastern and western States, and the Common Law has progressed differently. The conflict here is a snapshot wake-up call for those who realize that some 'common properties' are being consumed inappropriately because the property rights were not assigned wisely (like the ppm budget of our greenhouse gases, etc.).

Farm Boy is kind of right about the alfalfa. The farmers look at their wells. Then they look at their land. And then they figure out how to maximize their net profits based on how they combine them. If people were to try to outright buy the water, the farmer would be happy to try to grow a less water-intensive crop. And cities are money-making machines, a liter of water is likely to generate much more money than selling the water to Chinese cows (that will then be bought by city-dwellers). And if Chinese cows are actually more profitable to sell to, then you're better off selling to Chinese cows and using the profits to buy alternative water sources. But, I doubt that's the way it would work.

Now, obviously, the lesson here is to start fixing these issues before the droughts. There were likely both scientists AND venture capitalists screaming for funding in previous years. The time to buy 'future water' is when water is cheap (likewise, the time to buy 'future energy sources' is when oil is cheap, not when budgets are being squeezed with increasing costs).

The best thing you can do as a Californian is try to increase your purchasing power, so that you can help fund alternatives as they're presented.

Now, Tim's mentioning immigration. That will increase the demand for water. The main question is whether the economic value of that influx (and all the concomitant trade) actually raises incomes faster than demand rises. Rising demand is only a problem when cost of supplying that demand proportionally rises. Water has a funny demand curve. Below 100 gallons per day (including embedded as food), we think of it as a necessity. After 100 gallons per day, it becomes a utility, then you can look at each specific gallon and say "hmmmn, the Market should decide if this is better transformed into beef, a green lawn, or to help frack"


Edit: worst case, desal brine could be piped out to the far ocean. It's the intensity of the change in salt concentrations combine with ecosystem diversity that causes the eco-threat. But piping it out so that comes out in relatively dilute (multiple) plumes, in regions of low biological activity, would be fairly harmless.

 

[Farm Boy]

And as we all know, happy cows don't stand around in snow up to their ears.

A well run confinement operation goes a significant way towards alleviating temperature concerns. Though, cows aren't a totally great fit for that. Pigs work a lot better.

 

[Timsup2nothin]

A well run confinement operation goes a significant way towards alleviating temperature concerns. Though, cows aren't a totally great fit for that. Pigs work a lot better.

I'm just guessing that the "happy cows come from California" ad campaign does not play heavily or well in Illinois. Am I right?

 

[Farm Boy]

Lawl!

You seeee, weee're tryiiiiing to shaaaare our conceeeeeerns abouuuuut the weeeelfare and aaaaactualization of our slaaaaughter beeeings. Iiii'm suuuure the reeest of the couuuuntry will catch uuuup on the eliiiightenment train after waaaatching us for a whiiiile.

 

[Wolfbeckett]

Edit: worst case, desal brine could be piped out to the far ocean. It's the intensity of the change in salt concentrations combine with ecosystem diversity that causes the eco-threat. But piping it out so that comes out in relatively dilute (multiple) plumes, in regions of low biological activity, would be fairly harmless.

Interestingly, the desal plant that originally sparked this discussion here in San Diego is intentionally being built right next to a power plant for exactly this reason. The power company already uses sea water for cooling purposes and then pumps it back into the ocean, and the desal plant is leasing the rights to use their runoff system so that they can mix their runoff together, diluting it before it even hits the ocean so that it won't have such a large ecological impact. Here in San Diego those kinds of concerns matter, people here LOOOOOOOVE the coastal wildlife, there would be an angry mob if some for profit corporation was destroying our coastal habitat.

Desalinization plants can make a huge difference. What we need is a series of huge ones solar powered and we'll send the water up to the mountains and let it trickle back naturally

If we're going to pump it all the way to the top of a mountain, I reckon it's cheaper and faster to just pump it to where we ultimately want it to end up.

 

[Timsup2nothin]

Lawl!

You seeee, weee're tryiiiiing to shaaaare our conceeeeeerns abouuuuut the weeeelfare and aaaaactualization of our slaaaaughter beeeings. Iiii'm suuuure the reeest of the couuuuntry will catch uuuup on the eliiiightenment train after waaaatching us for a whiiiile.

Well, that campaign is run by the California Dairy Commission... Committee?... whatever. Rumor has it the two bulls were approached by the California Beef Commission but their agent made too many demands so the project was scrapped. TV personalities! One commercial it goes right to their heads.

 

[Hygro]

we're going to pump it all the way to the top of a mountain, I reckon it's cheaper and faster to just pump it to where we ultimately want it to end up.

But not as magnificent.

 

[PhroX]

Interestingly, the desal plant that originally sparked this discussion here in San Diego is intentionally being built right next to a power plant for exactly this reason. The power company already uses sea water for cooling purposes and then pumps it back into the ocean, and the desal plant is leasing the rights to use their runoff system so that they can mix their runoff together, diluting it before it even hits the ocean so that it won't have such a large ecological impact. Here in San Diego those kinds of concerns matter, people here LOOOOOOOVE the coastal wildlife, there would be an angry mob if some for profit corporation was destroying our coastal habitat.

I've actually been working on the design of a large desal plant in Chile recently, and to be honest, it's not that hard to design a desalination plant such that the impact on the ocean from the highly saline discharge is minimal. If you just dump it striaght out of a pipe by the shoreline, yeah, that's a problem, but a good diffuser*, combined with some degree of dilution before the brine is discharged, and you pretty much have to be right next to the outfall in order to detect any increase of salinity. I forget the exact requirements we were designing to (my work was more on the intake than the outfall), but typical criteria for outfalls are in the region of being unable to detect any rise in salinity above the background level 20m from the outfall.


* a diffuser is a type of outfall that spreads the discharge over a wide area. In our case, we have 2 pipes roughly 80m long, situated on the sea bed 300m offshore, each of which had a dozen individual discharge ports along their length. Basically, the amount of brine discharged at a signle point is low enough that the seawater will quickly dilute it.

As another rather interesting coincidence with this conversation, we are pumping the water from this plant to the top of a mountain. A mountain almost 200km away, on the other side of the Atacama desert.

 

[El_Machinae]

You'll want nuclear, wind, and solar tech going full-bore, 'cause burning oil to get water strikes me as nuts

 

[Timsup2nothin]

You'll want nuclear, wind, and solar tech going full-bore, 'cause burning oil to get water strikes me as nuts

Given the available locations for desalinization plants, some sort of tidal harness generating system would be ideal.

 

[Sommerswerd]

If you just dump it striaght out of a pipe by the shoreline, yeah, that's a problem, but a good diffuser*, combined with some degree of dilution before the brine is discharged, and you pretty much have to be right next to the outfall in order to detect any increase of salinity.

So dilution is achieved by spreading the brine (I'm assuming this is a sort of super-saturated salt slush) into lots of different places, rather than diluting the actual brine (because that would require water, which would defeat the purpose of desalination).

So is the principle then that the ocean is so big that pouring pure salt into it has almost no effect, or is it more like a "has no effect as long as desalination is only done on a relatively small scale" kind of thing?

Is there any other way we can use the salt, rather than putting it back in the ocean, like eat it for example, or use it to melt snow off the roadways? Or is that impractical?

 

[PhroX]

So dilution is achieved by spreading the brine (I'm assuming this is a sort of super-saturated salt slush) into lots of different places, rather than diluting the actual brine (because that would require water, which would defeat the purpose of desalination).

So is the principle then that the ocean is so big that pouring pure salt into it has almost no effect, or is it more like a "has no effect as long as desalination is only done on a relatively small scale" kind of thing?

Is there any other way we can use the salt, rather than putting it back in the ocean, like eat it for example, or use it to melt snow off the roadways? Or is that impractical?

Brine is the usual term from "high salinity water". To be confusing, seawater itself can sometimes be called brine (particularly when people are being poetic), but with regards to desalination, it's basically the stuff you don't want. Calling is "slush" though is not particularly accurate, it's not that high in salt - for example, it would still look like water. For this plant I've been working on, for every 1l of seawater taken in, it produces roughly half a litre of "fresh" water, and half a litre of brine (which is returned to the sea), so the latter has about twice the salinity of seawater. Even with the maximum discharge rate of approximately 5000l/s, compared to the amount of water even in the sea immediately around the diffuser, it's not that much extra salt. While achieving higher efficiencies (and thus more concentrated brine) is possible, it's not as efficient.

Some dilution is done directly - abliet with seawater rather than the product water. Up to about 15% of the plant intake can be taken from the flow before the desalination itself, then mixed with the brine to reduce the salinity if it rises too high (as the salinity of the brine does vary depending on a whole range of plant operation factors).

On an overall scale, there's plenty of water in the sea to dilute whatever we do. Having a noticable effect on the salinity of the sea as a whole would be nigh-impossible. However, on a local scale, then it really comes down to how much high-salinity water you're discharging, over what area and the conditions in the sea (currents, tides, temperature variations etc. will all help mix the water and carry the salt away from the outlet). Though as long as the outflow is reasonably well dispersed there shouldn't be a problem. If it isn't, you could get very localised areas (i.e. around the outlet) in which the water is consistently too saline for life.

Using the salt for other things isn't really practical because, well, you haven't got salt, you've got saltwater. Sure, if you had a plant that made "useable" salt from seawater, it would be a little easier for it to work with desalination brine, but in general, doing anything with it is more expensive and has a much much higher energy consumption than simply putting back into the sea in a manner that prevents excessive local concentrations.

[note, all this is for a reverse osmosis type plant, I'm not that knowledgeable on more traditional thermal desalination, but the former is the type that would be used in California due to the latter consuming vast amounts of energy (making it popular in parts of the world where oil is cheaper than water....)]

 

[Timsup2nothin]

So dilution is achieved by spreading the brine (I'm assuming this is a sort of super-saturated salt slush) into lots of different places, rather than diluting the actual brine (because that would require water, which would defeat the purpose of desalination).

So is the principle then that the ocean is so big that pouring pure salt into it has almost no effect, or is it more like a "has no effect as long as desalination is only done on a relatively small scale" kind of thing?

Is there any other way we can use the salt, rather than putting it back in the ocean, like eat it for example, or use it to melt snow off the roadways? Or is that impractical?

My knowledge is limited to small scale desalinization, because it comes from ships, not public utilities, so take this with...er...a grain of salt.

We took in a hundred gallons of seawater for every gallon of fresh water produced. So our ninety-nine gallons of brine that went overboard could not be in any way described as 'salt slush'. Salinity of sea water runs about 35000 ppm, and the brine ran about 35500 ppm. The only way we were going to make a notable difference in the seawater is if we got trapped in a small lagoon for a decade.

Now, a public utility plant is going to process a huge volume by comparison, but the same thing applies. The only way they are going to make a significant difference in the ocean is if they are somehow repeatedly processing the same water.

EDIT: Note that I am awestruck by the efficiency of the plant in the crosspost...50%?

 

[PhroX]

EDIT: Note that I am awestruck by the efficiency of the plant in the crosspost...50%?

I suspect that your ships used thermal vacuum desalination (basically, boiling off water, albeit at lower temperatures than 100C, and collecting it) It has high energy consumption (likely not too problematic when you have a nuclear reator on hand), and relatively poor efficiencies but is very easy to set up and operate, making it great for things like ships, and places with energy to burn.

Reverse osmosis (using a semi-permeable membrane which allows water but not salt to pass though, but pressurising the system such that instead of water flowing from low-saline to high-saline, it is reversed) is much more efficient in terms of water, although achieving the kind of efficiencies we're getting in this plant requires a pretty high pressure, and takes less energy (though still a non-insignificant amount), but has much much higher set up and non-energy operational/maintenenance costs and is more complex to operate. I believe it requires much cleaner water as well, so the seawater must be treated before it can be desalinated.