The next few posts were written to be read from the top down. Hope you like them.
Monthly Archives: December 2008
Field and basin efficiency in general.
The junkies among you can read a more technical description of field and basin efficiency here, or see a sketch of a description in this slide show (which only makes sense if you already know the topic).
The reason I don’t like to talk about field and basin efficiency is that ag advocates are known to do a sorta bullshit sleight of hand, saying that their “efficiency” is some amazingly high number (anything higher than 90%) and so they don’t need to listen to any more of this talk about new irrigation practices. If they are talking basin efficiencies, that means that for some large boundary, perhaps their water district or a watershed, the amount of water they collectively apply is only barely more than collective crop demand, and presto! Everyone in that area is a very good irrigator. Except they don’t really say “basin efficiency”. They say “efficiency” or “district-wide efficiency”, and hope that you will be suckered into thinking that they mean the average of every single grower’s field efficiency.
Field efficiency comes from matching irrigation water to crop demand on a single field or small farm. This is the realm that individual farmers can influence, with the type of techniques that the Pacific Institute talks about (irrigation scheduling, crop shifting). If every single grower had an field efficiency in the 90s and you averaged them to get some average field efficiency in the 90s, that would indeed mean that you are talking to very skilled irrigators who don’t need any advice from you. But having a basin efficiency in the 90s doesn’t mean everyone is doing a good job applying a precise amount of water. It just means that water gets used again and again within the big boundary area.
I kinda resent giving the idea of basin efficiency much credence, because some advocates use it in a sneaky way to imply that all their irrigators are doing a good job. I also don’t like that some advocates use the idea of basin efficiency to say that there is no good reason to improve their practices on the smaller field scale. This isn’t true, as both the irrigation professors and the Pacific Institute report point out. What high basin efficiency can look like in practice is that growers overapply water at the top of the basin and other growers use it again, as tailwater with pesticides or fertilizers or salts in it. Or it sinks into the ground and other growers pump it out. Or it returns to the river, salty and warm, and gets diverted again. You could still have high basinwide efficiencies, but you pay costs in water quality or pump energy or crop yield. Taking more water than you need (because it will return soon enough or so that it can percolate into groundwater) hurts the rivers it was diverted from; fish would like to live in that clean cold water until the very last second before it gets used. So yeah. There are real problems with using high basin efficiencies to give yourself a free pass.
On the other hand, there is no denying that it exists. A lot of diverted water gets used several times. It is a cheap way to move water, or at least a way to move water that externalizes some of the costs. Further, people have been living in this connected system for two generations now. I have to think they have roughly optimized their positions and come to rely upon them. Getting someone else’s water after it ran off the field may not be a good way for the system to work, but at this point, I’m inclined to think it is the best bet for that second grower. They’ve had forty years to debate sinking a well or digging a pipe directly to the river. If they thought those were better for them than taking tailwater, I think they’d have done it. Disrupting that system (like, if you had the grower at the top really cinch down on irrigation efficiency) will probably put downstream growers in a worse position. To the extent that it means that they’re internalizing their environmental costs, I’m fine with it. But as much as they perceive it to damage their interests, they’ll fight that.
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Field and basin efficiency in the Pacific Institute report.
Yeah. They missed the ball on this one. I mean, they talk about field and basin efficiency on pages 14-16, but didn’t follow through. If water is used several times in a basin, then the amounts you could save by practices that make each field more efficient aren’t additive. If you improve the top field from 70% efficient to 85% efficient, all the downstream users have also had a chunk taken out of their supply. If they applied management and money to adjust for that missing chunk, their efficiencies would all move upward some small percent. If they don’t adjust their field efficiencies up, they’ll go get more real water from somewhere. Either way, you can’t add up all the yields from improving field efficiencies as if they were separate. Shit. This is hard to explain. Ummm…
The potential for wringing water out of California agriculture is NOT:
(new improved field efficiency – old sloppy field efficiency)(annual applied water) = bonus water for fish AND cities AND still plenty for ag!
It would be like that if all of the farmwater were completely independent. Then you could add each efficiency improvement up separately the way the Pacific Institute report does.
The potential for wringing water out of California agriculture IS:
(new improved basin efficiency – old sloppy basin efficiency)(annual applied water) = not a whole hell of a lot.
Keeping in mind that I don’t like the concept of basin efficiency any more than you do (because people with an agenda use it for evil), when I hear estimates for basin efficiencies in CA, they’re on the order of 95%. Considering that groundwater levels are dropping drastically, I do not believe that there is a free 10% of inefficient water use sloshing around aggregate Great Valley agriculture. It is also worth remembering that is gets pretty expensive to go after the last few percents of efficiency. Your early gains are all big and cheap, but your last gains start to cost real money.
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Missed it by a lot.
Perhaps the most persuasive piece of the irrigation professors’ critique was this text box:
If so much water is being wasted as implied by the estimates of potential savings in the PacInst Paper, it would have to be going somewhere. That somewhere could only be into the ground or out through rivers. But we know that there is a huge groundwater overdraft (perhaps 2 million acrefeet/year) in the San Joaquin Valley and the San Joaquin River runs dry near Dos Palos in the summer. (emphasis in the original)
It sounds facile, but it is true. The Pacific Institute efficiency argument says, in effect, that 3.5 million acrefeet of water is sloshing around California agriculture, not being taken up by plants*. If so, where is it?
There aren’t many choices. The Tule Lakebed doesn’t hold a three foot deep lake in August. Excess irrigation water sure isn’t draining to the San Joaquin River. In fact, look. The western part of the San Joaquin Valley sends about 50,000 acrefeet/year of really gross water to the Grasslands Bypass Project (16,000 af this dry year). Fifty thousand acrefeet a year? Draining the better part of the west side of the San Joaquin Valley? You’ve got to show me a whole bunch more bypass projects to come up with the other 3.45* 1.65 million acrefeet the Pacific Institute says is loose water. Or you could show me rising groundwater levels, as the ground soaks up excess irrigation water. Except you can’t, cause they aren’t there.
The only explanation I can come up with for such a huge gap between building upward from models of field irrigation efficiency and working downward from a valley-wide water budget is double counting. I think the Pacific Institute method of adding up efficiency improvements from all those farms double (and multiple) counts the same chunk of water each time it gets re-used as if it were separate chunks of water from which you can extract 10% every time. That’s why I don’t think there is potential to get 3.5 maf of water from Great Valley agriculture and have ag stay at current levels.
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Which is why…
I think that a report that describes efficiency improvements that let ag farm happily while 10% of the water they use goes elsewhere is a false promise. It is balm for urban users and enviros, who would like to trade money for efficiency improvements for real wet water and still leave ag whole and happy. But that isn’t realistic. I think ag would contract sharply if big pieces of water weren’t available to them*. If we’re honest, that is the discussion we should be having. Of course water for the uses Californians value will come out of ag water use. It is that, new dams**, or tapping Wild and Scenic Rivers, and all the hippie urban votes will come down against ag. I think we should be planning a managed retreat for agriculture. I don’t think ag should be fighting to protect the acreage they’re farming now. They should be fighting to protect whatever core they value and to extort as much exit money out of the Californian collective as they can.
The rough estimates I talked about a couple days ago can give us an idea of scale. Six million acrefeet of lost snowpack storage? Cities and rivers jonesing for another 3.5 million acrefeet? That’s three million acres of farmland, out of about nine million acres***. Some of that farmland will retire itself. About half a million acres on the west side of the San Joaquin Valley are saltifying (a process that will speed up as climate change makes the weather hotter, which means applying and evaporating even more slightly salty water). We’re gonna lose about 100,000 acres in the Delta as islands collapse. (Sweet graphic here. ) Urban encroachment will take out a bunch more acreage (although perhaps less, now that we have new urban planning legislation to discourage sprawl.). So, you know. Maybe 800,000 acres out of 3,000,000 acres will retire themselves.
The rest will involve choices. We could let it happen without planning, in which case ag will be eaten from the bottom up and by chance, with financially vulnerable farmers collapsing in a hodge-podge. We could institute a water market, which will arrive at an economically efficient outcome, regardless of whether we like an economically efficient outcome. A really fucking stupid way to do it would be based on order of seniority, with more recent farmers having to take the hit first and farmers that have been there a long time being protected until the end, no matter what they grow or how. That’d be unbelievably stupid.
Or, we could choose something. We could decide that we like certain farming practices and preserve the farm acreage that uses them. We could decide what we want six million acres of farmland to look like, on what soils and where and how big the farms should be, and design a system that supports those. We could choose to save the acreage on the best soils. We could choose to maintain the agriculture that supports rural communities. We could choose to retire the acreage that would make the best wildlife habitat when retired. We could decide it isn’t our responsibility to feed the whole country (which has perfectly good farmlands of its own if they weren’t growing corn and soybeans) at the expense of our own rivers. I don’t want to shock you or anything, but what I’m saying is that we could apply priorities to get the best possible outcome from a large, wrenching re-alignment.
But we will not face choices like that, or even admit that we have to make them, if we cling to the hope of efficiency gains that will let us carry on as usual. That’s my real gripe with the Pacific Institute report.
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Aaaand…
That’s why I’m so disappointed with the outcome of the Ag Vision process. So much time and comment and thought went into crafting a vision for California agriculture in 2030. Truly, the transcripts of their public meetings are amazing and you should read them for firsthand accounts of what it is like to farm in California*. All that knowledge and expertise, and they came out with a bunch of platitudes? I mean, really? The framework reads like “we want a bunch of obvious good things”. Well yeah. I do too. This is still bigger-pie territory, not facing-hard-trade-offs territory. Bummer.
*Hee. I am not just telling you that you should read government reports for fun. I’m directing you to read transcripts of public meetings for fun. Rock on.
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I will never explain the unit “acre-foot” on this blog.
I’ve been slow to finish up my review of the Pacific Institute report, because that will mean that I have to get into the concepts of field and basin efficiency and I dread that. I don’t mean to be a tease; I know how badly you’ve been craving more of this series. I’ll put some peripheral thoughts here, so we can have a clean discussion of field and basin efficiency and the core conclusion of the Pacific Institute report without them buzzing around and plaguing us.
A thought:
I agreed with the technical critiques in the irrigation professors’ report, which isn’t too surprising, since one of them trained me. If you have any technical questions about anything in those reports, I’d be happy to take my best shot at answering it. As much as those critiques cast doubt on whether the Pacific Institute report is identifying real potential for water savings, I’m also a doubter.
Another thought:
I said that I’d critique the Ag Water Management Council’s report. Here goes. This is self-reporting by a self-selected group of the most progressive ag water districts. I don’t think the claims are very impressive; there’s a lot of hedging about how far along the districts are in adopting Efficient Water Management Practices. That said, these leading districts are alert to the practices and implementing them at some rate unspecified by the report. I don’t take this report as proof that ag is doing everything it can. It is more like the best likely spin you could put on ag’s water use practices. Also, man. Love the pictures.
Yet more thought:
For your sense of scale, here are some recent rough numbers.
3.5 million acre-feet/year – the Pacific Institute report thinks this is the amount ag could yield without hurting, or maybe even while doing better.
31.5 million acre-feet/year – this is roughly how much ag applies overall. Am I really doubtful that irrigated ag could give up 10% of its applied water without hurting? Are they really so tight that there isn’t 10% slack in the system? Yeah, I really am doubtful, and I’ll tell you why when I tackle the field and basin efficiency talk. But OH LOOK!
6 million acre-feet/year – this is how much warmer winters will cost CA in snow storage of water by mid-century. That’s twice the amount we’re wrangling about in the Pacific Institute report, so as much as the Pacific Institute report seemed to be making bold claims, this should be twice as dramatic.
I’ll give you three more numbers that I find really handy.
10 million acres – the rounded-up area of irrigated ag in California. It is closer to 9 million acres these days, but 10 million acres is easier to use.
California is about 100 million acres.
As a very, very rough estimate, one irrigated acre uses about three acre-feet of irrigation water a year. (This goes neatly with the 10 million acres and 31.5 million acre-feet/year.)
These are the numbers I use to get a gut sense of things*, decide whether a claim is big or little or ridiculous. You may use them too.
Filed under Basic stuff, Irrigation!
More on the Pacific Institute report
The Pacific Institute report writes in the “Efficient Irrigation Technology” section that considerable water could be saved if growers used drip or sprinkler systems instead of flood or furrow. This is a reasonable sounding concept that falls apart when you get to specifics. To get the kind of savings the Pacific Institute estimates (0.6 million acrefeet), you’d have to convert a whole lot of acreage to drip or sprinkler. So much acreage, in fact, that much of it would have to be field crops. In their report critiquing the Pacific Institute, a few irrigation professors wrote this paragraph, which I loved because it shows why the details matter so much:
The flood to sprinkler conversion on field crops would need to occur on alfalfa, pasture, cotton, or corn. Cotton acreage is now less than 300,000 acres (not the 886,000 acres used in the report), and sugar beet acreage in the Valley will disappear soon. Safflower is most often minimally irrigated and rice is not a candidate for sprinkler irrigation. Corn is problematic to sprinkler irrigate due to its height, which would require that center pivot or linear move systems be installed. While alfalfa and corn prices have been strong lately, the cost of conversion from flood to sprinkler irrigation is considerable and may not be justified by field crop growing economics. (pg 11)
This is such a good summary of why it gets very hard to talk about ag and why the sides of the debate tend to harden. I mean, it sounds right and obvious, that field crops should change from flood irrigation methods to sprinklers or drip irrigation methods. Except that as you discuss each specific field crop, each one doesn’t make sense. What cotton? What sugar beets? Safflower? Safflower is underirrigated now; why would you underirrigate it with expensive sprinklers? Corn is too tall for ground-based sprinklers and center pivot sprinklers don’t work well on California soils. Wheat is a winter crop, rainfed. Rice stands in a shallow pond you couldn’t fill with sprinklers. Alfalfa maybe, although you’ve got your tractor in there ten times a year to cut alfalfa, which could be hard on solid set sprinklers and no good for driplines. The nice thing about alfalfa is that amazing tap root, the one that makes it possible to let the plant go dormant in drought years, and that should be encouraged by really deep watering.
So here’s where the mutual exasperation comes in again. Enviros and urban-types say “Look, we know that if you switch to sprinklers you save water. This is known, and the need for water is urgent.” Ag answers curtly, because it is tired of repeating long explanations, “Whatever. That won’t work.” Enviros think growers are digging in because they have lots of water rights and are politically powerful and change-resistant. Growers wish enviros would stop insisting they make expensive nonsensical technology changes without demonstrating benefit in their real-life circumstances. This is a pretty big gap, between the plausible general principle of the enviros/urbanites and all the many, many constraints and specifics of ag. You can see how someone could get real vested in one or the other. It doesn’t help that ag’s objections look exactly like self-interest and that it is easy to point to historical poor practices. Or that enviros seem to want growers to go to a whole lot of expense and hassle so that they’ll have the privilege of forfeiting some water.
How will this be bridged, so that growers will make the worthwhile technology switches and enviros trust that the remaining systems are using water appropriately? Economists would say that pricing water without subsidies or protections would solve all that, and I agree that it would go a long way. Besides, no one would have to talk or trust or convince or agree on anything and god knows we hate interacting with people who are different from us. So there’s that. The other two choices are that enviros learn more about ag, enough to shake some of their certainties about how wasteful ag water use is. Or that growers change their systems because of other pressures, like drought or rising energy costs if they pump groundwater. I suppose it is possible that with enough mutual education and discussion, the sides could make careful compromises based on mutually established facts. But that isn’t the outcome I expect.
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It is also true that Mendota is hurting.
In an editorial in the Sac Bee today, the spokesperson for the State Water Contractors objects to a ruling last week that restricts pumping through the Delta to protect Delta smelt. (The thinking behind the ruling is that smelt get churned to bits in the pumps, and also that the pumps make the Delta currents so messed up that it damages smelt habitat.) The new argument against shutting down the pumps is “But there are other problems toooo!”1
Every day, Sacramento’s wastewater treatment plant sends 13 tons of ammonia downstream to the Sacramento- San Joaquin Delta, potentially disturbing the Delta’s food web in profound and destructive ways. Agricultural runoff flows freely through the estuary’s waters. Exotic species of clams consume much of the critical food supply. Nonnative fish prey on native smelt and salmon.
Unchecked and unmanaged, these and other threats to the Delta’s fisheries are tolerated on a regular basis. Yet, in an imbalance that grows greater with every passing month, the already heavily regulated water projects in the Delta – projects that supply water to millions of California residents, businesses and farmers – get hit with restriction after restriction on water flows.
It just now occurred to me that the State Water Contractors may be hitting up against a concept that is even more engrained than “must give water to farmers”. This may be a head to head contest of “must give water to farmers” vs. “dilution is the solution to pollution.” I mean, diluting pollution is the prime historical way of dealing with water (and air) quality problems, an easy solution that makes problems temporarily go away. It is a strong and early impulse for humans. And now that we don’t know how to fix the smelt, we’re starting by throwing water at the problem. Turn off the pumps! Let water run through the Delta! Ammonia from the Sacramento? Pesticides from the San Joaquin? 2 MORE WATER for smelt! 3
I really do love seeing human verities fight it out; I’ll occasionally idly ponder which of two impulses is dominant, but you don’t often get good real world test situations. I have to confess I like watching a group that doesn’t have a track record of caring about pollution get burned by old-school pollution remedies. Perhaps if they hadn’t fought or dodged that conversation for decades, we would 1. not be in this mess or 2. have better tools to use now.
1 I find this unpersuasive. Yes, there are other problems too. But the pumps are a known major factor, and even better, under direct and centralized control. Take the major easy fix first, then work hard to address the other factors. Do not take the other factors as reason not to do anything.
2 Heh heh. I notice that the spokesperson for the State Water Contractors (farmers in the San Joaquin Valley) did not put that on her list of threats to the Delta.
3 I’m not opposed to this, by the way. This isn’t as sophisticated as, say, developing technologies and practices that keep nasty chemicals out of our rivers in the first place and addressing invasive species directly, but given that the smelt are on the verge of extinction, it seems like a pretty good crude tool to start with.
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Working Landscapes Adaptation papers
Quick break in the discussion of the Pacific Institute’s ag water report to summarize a couple different papers. The Working Landscapes Sector has put out two adaptation papers, one for forestry, one for agriculture.
The who?
These were written primarily by groups of bureaucrats from the relevant agencies. They are a continuation of the groups that were formed to write the different chapters of the Air Board’s Scoping Plan. These groups were open to the public and email lists compiled from sign-in sheets, but this is mostly the work of government staff, from the Air Board and CALFIRE* and from the California Dept. of and Ag. This is actually a really exciting new development, having state agencies work on papers together. You wouldn’t think it would be a new innovation, but the Governor has informed the agencies that all of our plans must say the same thing! We are quite excited by the prospect. Anyway, it means that rather than having the forest expert over at the Air Board write this paper, the forest expert at the Air Board now writes this paper with people from CALFIRE and anyone else who chooses to attend these meetings.
I do like the name and concept of Working Landscapes. Not the layabout beaches or those frivolous cities. Working landscapes, that produce things but also have some Nature left in them.
The Forestry Adaptation Paper
A nice read. Pages 1-8 give a good overview of the types of problems they expect: less precip, most of it rain, means a longer dry season, means more fires and insect infestations. (I must not be paying attention, because I was a little surprised at the emphasis on insect infestations. I’ll have to worry more about those.) They expect ecosystems to move, possibly rangeland expansion. They explain the concept of resilience, which is showing up more and more in government reports.
Pages 8-10 talk about how to do planning. This stuff appears in a lot of papers and I can’t tell how much it needs to be repeated. Yes. We should do scoping and gather data, come up with strategies and leave room to change them. We should monitor things and decide whether we did a good job. This is all accurate, but it seems self-evident, no? Is it included in all these papers because they have to stand alone when the public comes by to read them? Or is it filler because we don’t know what else to say yet?
Pages 10-13 apply the planning concepts to forests, although they save the specifics for the appendix, and point out that the things they decide to do about forest adaptation will matter to a lot of other sectors as well. They close by saying they need more data, that not everyone agrees on what to do about forests and they don’t have the budget to do what must be done. We’ll see that a lot. I’ll give them props for saying that current laws may prevent them from doing “triage”. I find most reports tend to gloss over the legal setting they work within, forgetting that it may also require change. I also like when reports about climate change use words like “triage”.
The Agriculture Adaptation Paper
The agriculture group apparently does not care about things like overviews or explanations for a broad audience. Keep up, public! Thankfully, this saves us from another description of the planning process. Instead, with no foreplay whatsoever, they go straight into bulleted lists of What To Do. I like their list a good deal.
I started summarizing it for you, but it is hard to further reduce bulleted lists. It does a nice job covering each further subdivision: diversity in ag, water, flood, ag pests, soil carbon. You’ll notice that the theme of money comes up often. Pay farmers, however you can. Get federal monies or pay them to sequester carbon or create markets for new weirdo crops. I don’t know where the truth lies on this, but there are two opposite perceptions of ag. One is that they are rich and exploitative agribusiness that sleep on pillows of hundred dollar bills; the other that they are barely scraping by each year, always on the brink of losing land and utterly unable to pay for new capital or higher wages. Like I said, I don’t know which it is, but we write policies as if it were the latter.
They do not talk about land retirement or saltification, and I notice they don’t talk about succession planning. The average age of a grower in California is 57**. Presumably there’ll be some sort of transformation within 15 to 20 years. That could go into our planning.
Both papers provide bibliographies, in case you burn with the need for more.
*I don’t know why the forestry department is now CALFIRE with the ALL CAPITALS. Oh. Mr. Google says that they changed it to sound catchy, like CalTrans. Whatever. CalTrans doesn’t shout its own name all the time.
**Completely unsourced and unreliable common knowledge.
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