Monthly Archives: February 2014


This is a nice clear piece on system re-op. Whenever you hear someone say ‘system re-op’, this is basically what they mean. After you read that, come back to talk about water modeling.

Andrew Sullivan thought Dr. Lund’s analysis of a dry climate hydrology stood out of the longer article on California water.

Even with the worst conceivable climate change, the kind of global warming that brings 70-year droughts to California, the state might do okay.
That seems counterintuitive, but that’s what Jay Lund, who heads the UC Davis Center for Watershed Sciences, loves about his model of the state water system, CALVIN. He and his colleagues ran a range of climate scenarios through CALVIN, asking for a look at what very dry, very warm scenarios might do to the state’s water system out to the year 2100. The results were shocking.

Basically, in CALVIN’s rendering of the future, the state’s economy is fine. “It was amazing how little the damage was to the state’s economy,” Lund said. …

Agriculture does not fare quite as well, but the state’s agricultural production only falls 6 percent. That’s despite increasing urbanization of agricultural land and, in the driest scenario, a 40 percent reduction in water deliveries to the Central Valley. “The farmers are all smart people and they’ll cut back the least profitable stuff,” Lund said. They’ll also fallow land, according to CALVIN—roughly 15 percent of the irrigated parcels currently farmed today, or 1.35 million acres.

I am sure that’s what CALVIN said, but you have to understand what CALVIN does to interpret it. (Dr. Lund, I know you stop by. Apologies if I don’t get this right.) CALVIN is an optimization model; when it does a run, it is hunting for the best possible outcome it can get by following the rules of its reservoirs and canals and fields and cities. Even more important, CALVIN knows the entire what, ninety? years of its hydrology all at once. It has perfect foresight. So basically, when it starts optimizing, it can look forward in 2012, see that the next two years (2013, 2014) are dry, and stash all the water it can. It also doesn’t have to hedge on whether to empty reservoirs before a flood; it knows whether a flood is coming. If there are no floods coming, it doesn’t have to empty reservoirs and can hold tight to stored water. When you know your hydrologic future, you can do a lot to store or release water smoothly.

I am not telling you anything shocking about CALVIN; all the modelers know this. But the best outcomes out of CALVIN include something we don’t have, which is specific, detailed knowledge about the hydrology in the future. When I see a surprisingly good outcome from CALVIN, I generally take that as the most optimistic case. Sure, we could do that well if we are perfect optimizers who know the future. Then I mentally adjust for being not-perfect optimizers who don’t know the future and figure our real life results will be somewhat worse.


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They can only vote against you once each.

From Circle of Blue:

Because the state has such variety in its aquifers and management agencies, local control is important, said Dennis O’Connor, the principal consultant to the Senate Committee on Natural Resources and Water and the Senate’s point man for groundwater policy. But the governor’s office is floundering on the details.

“I don’t think they know what they want to do,” O’Connor told Circle of Blue on Wednesday, having just come from a meeting with the governor’s staff. “I don’t think they can articulate what they want to see manifested in a new groundwater policy.”

The governor’s 2014-15 budget proposal does include $US 11.9 million for groundwater, money that will be used to hire enforcement staff, monitor aquifer levels, and assess pollution in aquifers used for drinking water.

The reason they cannot articulate what they want to see is that everything that would work is taboo. It is so taboo, in fact, that I would be surprised if it even gets brought up and rejected. The things they will say aloud, even in the privacy of the executive suite, are either already in process (monitor levels) or so trivial that the drought immediately exposes the suggestion as ridiculous.

Here is what the governor’s office could do if it wanted to address groundwater with the seriousness that matches the drought, and the extent of overdraft and subsidence. They declare groundwater to be a resource that belongs to the state. They figure out safe yield from the basins in the San Joaquin Valley. They might assign that to overlying users by some rule (weighted by acreage ownership) or they might auction it off (using the proceeds to do something useful). They accept that irrigated acreage will go down as a result, since growers have been mining groundwater for decades to expand irrigated acreage beyond what precip and safe yield can provide.

This isn’t conceptually hard or complicated. It exists in the world already. It exists in some groundwater basins in California already. The governor’s office won’t propose the thing that would work because it is politically taboo, not because it is beyond us to fix this problem. So they won’t say (or maybe even think) the thing that would work and they’ve already said the other banal benign things. They’re left with nothing, which shows through to observers.

You know, Governor Brown. They already hate you for the high speed train. You aren’t getting them back. Why not use the drought to get ‘er done? Save the San Joaquin Valley aquifers by fiat emergency powers; their grandchildren will thank you.

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No love on Valentine’s Day.

From the NY Times:

This year, Ms. Woolf’s farm will be forced to rely entirely on the ground wells it owns, pumping what they need to keep the existing crops healthy. But there is no way to know how much water is available underground — and with neighboring farmers doing the same, it is only a matter of time before the wells run dry.

“It’s like a bank account that is going to run out, and you don’t know when,” Ms. Woolf said, standing near her fields of garlic, where workers were laying rubber irrigation tubes under the murky cloudless skies.

I have absolutely no sympathy for this predicament. It could not be more directly or more blatantly self-inflicted. This is the direct result of their own choices, and has been clearly evident to every observer for years. You know, even records and monitoring started in 2009 would be useful now. Fuck ’em. Let them wonder how much water they have left in their aquifers. They have only themselves to blame for not knowing.


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Less than $5B/year, I presume.

The drought in California, the top U.S. agricultural producer at $44.7 billion, is depriving the state of water needed to produce everything from milk, beef and wine to some of the nation’s largest fruit and vegetable crops, including avocados, strawberries and almonds. Lost revenue in 2014 from farming and related businesses such as trucking and processing could reach $5 billion, according to estimates by the 300-member California Farm Water Coalition, an industry group.

That estimate of lost revenue, $5B, could be larger when the higher costs of power are added in to the additional power required to move substitute water. But let’s look at those rough numbers. Five billion dollars is 11% of $44.7B.

By the end of this rainy season, we are likely to have gotten twenty to thirty percent of average annual precip. For a 70% to 80% decline in the availability of a major input, our ag sector predicts lost revenues of 11%. Is that failure? Is that reasonable? What is a reasonable alternative, that we have enough infrastructure to perfectly buffer variable precip? In a drastic drought, should ag only have predicted lost revenue of 2% or 3%? What should we pay for that? Why should droughts be perfectly buffered by infrastructure? Why shouldn’t droughts be perfectly buffered? By whom?

UPDATE 2/14: The California Farm Water Coalition has increased their prediction of lost revenue to $11B. That’s 25% of an annual revenue of $44B.

Is a 25% reduction in revenue for a 75% reduction in precip too much? Who chooses? What are the alternatives? How do we want the system to work?


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If you are very good, we’ll send you some oranges for Christmas.

I see this quote everywhere; today’s example is from here.

California’s drought is especially worrisome because the state produces about one-half of the country’s fruits, vegetables and nuts. It is the No.1 agricultural state in the U.S.

The valuable information that never accompanies this quote is: how much of California’s irrigated acreage does it take to produce half the country’s truck crops? How much acreage would have to be fallowed in drought before any of those fruit, vegetables and nuts are lost to U.S. consumers?

Here are some tables from U.C. Davis’s Agricultural Issues Center that give a rough idea. (For the rest of what I put here, I’ll concede rounding and back-of-the-envelope estimates. If I am wrong by five or ten percent, it’ll still give us a sense of proportion.) This is 2011 data. Straight off the top, about 15% of California’s agricultural produce is shipped to the rest of the world. (, pg 62, says 16% to 19% in the 90’s). But Table 1 says 14%. Let’s say 15% so the math is easy. There are roughly 9 million irrigated acres in CA.

9m acres * 0.15 = 1,350,000 acres of production exported

If more than a million irrigated acres went out of production, the U.S. could still have all of the fruits, vegetables and nuts it now consumes.

If we start looking at different crops, I find the drought less and less worrisome. Back to Table 1, which says that 0.64 of all almonds produced go to overseas markets.

800,000 acres of almonds * 0.64 = 512,000 acres of almonds exported.

If 500,000 acres of almonds went out of production, the ag sector would lose quite a bit of money. But the U.S. would lose not a single almond that it currently eats. Table 3 shows you where those almonds go. A third of them go to Europe. I am sure that if California could not provide Europe with almonds, Spain, Turkey and Iran would be delighted to help them out. I am also sure that if Europe could consume no almonds at all, it would not be the Siege of Leningrad. People have gone without almonds for their entire lives and still found meaning in their existence.

Table 1 says that half of pistachios and walnuts are sent overseas (55%); Table 3 says they go to Europe and China. Combined acreage of pistachios (250,000 acres) and walnuts (about 250,000) is 500,000 acres. We could lose half of that (back down to 250,000 acres) without endangering the U.S. supply.

Let’s do grapes! 850,000 acres of grapes; 0.27 exported out of the country (Table 1), one third of those to Canada (Table 3).

850,000 acres of grapes * 0.27 = approx 230,000 acres of grape exported.
230,000 acres of grapes * 3 af/acre = little more than 0.6MAF.

It would not go down in the annals of human tragedies if Canadians got no more Californian wines. This would not give me a single second’s worry about food security.

A third of dried beans grown in California and half of the rice grown in California are exported. You know what? I think that’s great! Those are important food staples that provide direct protein and calories to humans. I am not anti-everything ag. But if we are growing 750,000 acres of nuts for the rest of the world, then we’re shipping 2.25MAF/year of water away in the form of pleasant snacks. Fuck that.

I am the most parochial person you know, and were it up to me, I wouldn’t be providing lettuce to places east of the Sierras either. Y’all have the entire Great Plains to work with; I am sure you could figure something out if California decided we’d rather have our ecosystems than send you cheap blueberries. I understand that my views are in the minority. But rough estimates are enough to convey that irrigated acreage in California (9 million acres) has perhaps 1.5 million to 2 million acres of slack before important food crops for human consumption in the U.S. are threatened.

ADDED: For perspective, the regulars at UC Davis say:

Still, statewide overdraft is estimated diversely to average between 500,000 acre-feet a year to more than 1.5 million acre-feet a year

We send more water embedded in almonds, walnuts and pistachios overseas than we overdraft from the San Joaquin Valley aquifers every year.


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You should hear what I think of Dear Prudence.

Wow. This is a surprisingly crappy answer to a common question in Sacramento.

Why conserve water when it all flows back to the river?

The answer is not gobbledy-gook about the hydrologic cycle. There are two parts to a better answer.

The letter writer describes indoor water use, which he perceives as a more-or-less closed system (river, pipes to him, use by him in sinks and showers and washing maching and toilet, back into pipes to the regional sanitation plant, treatment, back into river). No conspicuous loss at any point.

For residential indoor use, there are two good reasons to conserve. First, this year, we have so little water stored uphill of us that we need to make what we’ve got in Folsom Lake last through to the next rainy season. It could really run out in August. We conserve now to stretch supplies longer in time. Second, even if diverting through the homes and humans of Sacramento caused no loss, that water re-enters the system downstream, at the treatment plant. We don’t have a way to pump it back up to us. It might not be lost to the next downstream person, but it is lost to our use in the dry months to come. (Also, it takes energy to move it and use it and treat it twice, and fish are left with a tiny muddy trickle in the parts of the American and Sacramento Rivers between the Sacramento city pumps and the regional sanitation plant.)

But the real answer is that most of the water used by Sacramentans is used outside (rule of thumb is that 70%-80% of residential use is outdoor). That isn’t a closed system. Some gets lost to evaporation and transpiration when it gets spread an inch thick over lawns on hot days. Some may trickle into groundwater and it isn’t clear when that gets back to rivers. I heard someone say that only 56% of outdoor water in the Sacramento region returns to rivers. That was hearsay and I can’t even remember the source, so make of it what you will. A good blogger would try to find you a number, but I think we can all agree that I am only a pale shadow of my former glory. Still, my answer is a lot better than an answer that missed two fundamental points (that we’re trying to make limited supplies last longer in time, and that most water use is outdoors, which is not a closed system).

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