Tree rings as history tool

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In my my tree ring book, I focused nearly entirely on their use in studying climates. But tree rings are good for so much more, as in this example:

Earlier this week, Royal Commission staff visited the Conwy valley, to work with Margaret Dunn, the director of the Dating Old Welsh Houses project in evaluating the final batch of houses, which will now be tree-ring dated by Dr Dan Miles and Dr Martin Bridge from the Oxford Dendrochronology Laboratory. Working in partnership with the Royal Commission, Dating Old Welsh Houses is a community-based history project focused on dating historic houses in the counties of North-west Wales and then compiling their house histories. In the last three years over sixty houses have been successfully dated by the partnership project and revealed some remarkable results. Contrary to the traditional view that North Wales was an architectural backwater in terms of houses, the results of the project show that the characteristic Snowdonian house took shape in the early sixteenth-century much earlier than previously believed.

 

How much water is there in the Colorado, and who needs what?

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As we await the release of the next release from the Bureau of Reclamation’s Colorado River Basin Water Supply and Demand Study, a story by Chris Woodka nicely captures the tension as basin states try to influence the process by telling the Bureau what their long terms needs are:

“I think the question is: ‘What is the result of overdevelopment of Colorado River water, and who suffers the consequences?’ ” said John McClow, an attorney who represents the Gunnison River basin on the Colorado Water Conservation Board.

McClow said the task is difficult because sharing the information with other states could hurt Colorado’s position in ongoing negotiations with other states.

It’s a classic game theory problem. States that acknowledge the river’s limitations and therefore limit their own water use risk losing supply to states that don’t.

Arizona’s cost of moving water could be about to go up

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The coal-Central Arizona Project link always seemed a bit of a Rube Goldberg policy apparatus to me. Its Goldbergness seems about to unravel.

Felicia Fonseca at the AP reports today on the potential costs of a retrofit to the Navajo Generating Station, up the hill from Glen Canyon Dam. The plant is part of a Byzantine deal to get water through the Central Arizona Project, which pumps Colorado River Water uphill to Phoenix and Tucson. The original plan was to build a series of power dams in the Grand Canyon to provide the electricity to move the water. That idea created one of western water’s great WTF moments, and the Grand Canyon dams were scrapped back in the ’60s. Instead, the government built a coal plant to generate the cheap electricity to move the water. Cheap, dirty electricity:

Requiring a coal-fired power plant on the Navajo Nation to further regulate pollution would not, by itself, force the plant’s retirement, but it could significantly increase water rates for agricultural users and American Indian tribes, a study released Wednesday found.

Stuff I wrote elsewhere: first steps for Navajo-Gallup pipeline

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From the morning paper, the US Bureau of Reclamation has taken a big step toward construction of the Navajo-Gallup Pipeline, which is a big deal around these parts:

Jason John, head of the [Navajo] nation’s Water Management Branch, called the request for bids on the pipeline “a huge milestone” in bringing water supplies to the traditionally underserved communities in western New Mexico, where residents have to haul water to their homes in tanks in the beds of their pickup trucks.

“We’re starting in that area because there’s an immediate need for water in that area,” said U.S. Bureau of Reclamation project manager Pat Page.

Stuff I wrote elsewhere: Elephant Butte

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Elephant Butte Dam was one of the first big concrete dam’s in America. It currently doesn’t have much water behind it. My column:

An enthusiastic crowd wandered the top of Elephant Butte Dam on Jan. 7, celebrating, with good reason, the structure’s role in New Mexico history. But it must have been hard to ignore the distance down to the water on the dam’s upstream face.

When they are brimful, with their outlets roaring, big dams like Elephant Butte are triumphal. But the big empty behind the dam, like we see this January in what looks like is shaping up to be a second consecutive year of drought on the Rio Grande, taunts our frailty.

The Jevons Paradox and greywater reuse

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Hey lazyweb – anybody know if someone’s looked rigorously at the question of greywater use in the context of a Jevons-like paradox?

Putting together some notes for a talk this weekend to the Xeriscape Garden Club of Albuquerque (Sat. 10 a.m. at the Garden Center if you’re in town), I’ve been thinking anew about the question of greywater use – running a second plumbing system from the sinks and other non-poopy waste producers in your house out to the garden.

It seems obvious that this is a winner, because you’re making use of the wastewater rather than just throwing it away. Except that in many settings, it’s not thrown away, but rather returned via the sewage treatment plant for use by others. Here’s the new National Research Council report on reuse:

[E]xtensive reuse has the potential to affect the water supply of downstream users and ecosystems in water-limited settings.

The NRC is talking about larger-scale reuse, but the principle is the same. If you’re on the coast, and your sewage outfall goes directly into the ocean, greywater reuse seems like a no-brainer. But in desert communities like Albuquerque, it’s a more complicated question. My sewage goes back into the Rio Grande, where it is used by others. A gallon I divert from my wastewater stream to water my garden is one less gallon we remove from the Rio Grande at the north end of town, and one less gallon we return at the south end of town. There may still be good reasons for doing this – energy, system losses, treatment costs, etc. But “saving” that gallon of water is not one of them.

So here’s the Jevons question. For those not familiar, in brief, the Jevons paradox is the notion that, as energy technology gets more efficient, rather than simply dropping our energy consumption, we at least in part do more of whatever it was we were doing with the energy. So as lighting got more efficient and therefore less expensive, one of the things we did was light up a lot more of our spaces.

What if, by using greywater, I figure that since I’m using water that’s kinda “free” in the context of both money and supply, I figure I can use more in the garden?

River Beat: a forecast for decline on the Colorado again this year

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It’s all fun and games until you actually have to measure snow.

The US Bureau of Reclamation’s first 2012 Colorado Basin reservoir forecast (the “24-month study”, pdf) projects a decline in total storage in lakes Mead and Powell, the Colorado River’s largest storage reservoirs, of 844,000 acre feet, or 2.76 percent.

Dec. and Jan. 2012 Colorado storage forecast

Dec. and Jan. 2012 Colorado storage forecast

There are two ways of framing this.

Let me start with the pessimistic, illustrated by this graph comparing the December and January projections. The December projection is based on no real forecast at all, but rather what amounts to an assumption of normal snow. There’s nothing wrong with this. That early in the season, the water managers have no idea what to expect, and they’re not making decisions based on the forecasters, so you could think of it as a placeholder. The January forecast is based on the first real numbers, which show a paltry snowpack in the upper basin – 66 percent (by one measure, the Colorado Basin Forecast Center’s aggregation of snow measurement sites upstream of Lake Powell) as of the date the forecast was made. The blue line is the December forecast, the red line is January once actual snowpack for the years is factored in. It’s down 2.2 million acre feet. But since that time, there hasn’t been much snow. The CBRFC Powell group today (Sat. 1/14/12) is down to 58 percent of average. Don’t put too much stock on the specific percentages (Danger! Amateur using Snotel!), but rather look at the trend. It’s down. With the forecast favoring dry through the end of the month, it’s reasonable to expect the projections to drop.

That’s the pessimistic frame.

Here’s the optimistic frame.

While an 844,000 acre foot drop is a lot of water, last year the total storage in the two reservoirs rose by 5.2 million acre feet. It would take six consecutive years of drops of the size currently projected for 2012 to wipe out the gains from last year’s bounty. From 2000-2010, during the Drought of the ’00s, the reservoirs averaged a 2 million acre foot per year drop. 844kaf is not a big number in that context.

Here’s my total storage graph, updated with the end-of-water year 2012 estimate from the latest 24-month study:

Total historic storage in Lakes Mead and Powell

Total historic storage in Lakes Mead and Powell (2012 projected)

What do you think? Which frame is “right”?