This is such an old story, but the new garb makes an interesting side-by-side comparison: a community faces tension as a new water user comes to town.

In Barnhart, in West Texas, it’s fracking for oil:

The Barnhart area has been hard-hit by drought, he said, just as surging oil and gas drilling activities have increased local water demands.

In Paso Robles, CA, it’s wine:

Where did the water go? Smith and other residents say it’s flowing freely into the area’s signature industry — wine.

Let us set aside, for a moment, the value judgments one might have about the newly produced products involved, and the fact that we love one while find the other abhorrent (I’ll let you decide which is which.).

What policies could be implemented in these communities to sort out the competing demands for scarce water?

I’m thinking I may need to update my tree rings book, or write a new one.

Much of my focus was on measurements of tree ring width, which makes sense. If you pick the right tree, the ring width can tell you whether a year was dry or wet. Thin rings mean the tree didn’t have much moisture to work with that year. But a rapidly growing new approach using the isotopic composition of the wood to tell us much, much more.

The technology’s been there for a while to do this, but improvements in isotopic analysis methodology make it possible now to do it with much smaller sample sizes, and much more quickly and economically. Here’s an example, from a research program aimed at reconstructing drought history in the upper Great Plains of North America:

Because old trees are scarce at low elevations in the arid inland western United States, ring-based flow reconstructions in large rivers are usually based on conifer trees in the mountains, where most of the run-off is derived. Such chronologies are important, but incomplete because they do not integrate events and hydrologic processes lower in the watershed. Ongoing work has shown that the dominant riparian tree in the lowland western United States, cottonwood (Populus spp.), is long-lived (as old as 370 years), cross-dates well, and has growth strongly correlated with surface-water flow (Merigliano et al. 2012, Friedman et al. 2012, Edmondson et al. 2013). Cross-dated sets of cottonwood cores from the northern Great Plains are now available for stable isotope analysis and past work in this genus has shown a strong relation between carbon isotope fractionation and drought stress (Leffler and Evans 1999). This presents the possibility of conducting multi-proxy studies using ring widths, stable isotopes, and possibly trace elements and radiogenic isotopes of both low-elevation cottonwoods and high-elevation conifers.

It’d be cool to see this done with cottonwoods here in the Rio Grande Valley. We don’t have 370-year-old cottonwoods, but I’m sure there are things to be learned.

Cynthia Barnett has an article in the fascinating new environmental publication Ensia about the problems we face globally because we’re pumping water out of the ground faster than nature puts it back in. One of the things I like about Cythia’s writing on water is her optimistic, solutions-oriented approach:

The solutions to overdrawn aquifers are similar to those for overdrawn bank accounts. Foremost is reining in overconsumption. Cities and farmers alike have shown that we can live with less water. Facing severe groundwater depletion in the 1980s, residents of Tucson, Ariz., have managed to reduce their daily Big Gulp from 200 gallons per person in 1985 to 130 gallons today. At the same time, the city has transitioned away from mining the aquifer as its primary source. Three-fourths of Tucson’s water supply in 2003, groundwater now accounts for less than half — with the remainder drawn from the Colorado River and reclaimed sewer and industrial sources.

And this:

The real test is whether people already in conflict can come to share and restore aquifers. Contrary to conventional wisdom, the Pacific Institute, which has tracked water conflict throughout human history, found that water has more often been a source of international cooperation than of war.