A Halloween treat: Lake Mead’s not quite as empty as we expected

I was wrong when I wrote in April that Lake Mead would continue to set “lowest ever for this point in the year” records for all of 2014. As I write this, with a few hours left in October, Mead’s surface elevation is 1,082.79 feet above seal level. That is more than five whole inches above the last really dry year, 2010! (data here)

But don’t get too excited. There’s a one in ten chance that Lake Mead will drop into the low 1,060s by the summer of 2016, according to the Bureau of Reclamation (data here, in pdf). That’s still above the trouble point for Vegas, which starts to have difficulty getting its water out of the lake at 1,050. But Southern Nevada Water Authority managers worry about water quality impacts well before that point (see these pdf/slides for an April 2010 presentation by Todd Tietjen of the Southern Nevada Water Authority for more on the issues involved). Here’s a chart, though it stops in January 2016, before things get really scary. On the plus side, there’s more upside than downside in the range of possible outcomes here:

Lake Mead projected elevations, courtesy USBR

Lake Mead projected elevations, courtesy USBR

Sustainability, Texas style

What economists call “weak sustainability” is the notion that, as you deplete some stock of natural capital, you reinvest in some stock of replacement capital. An example might be taking some of the surplus from extracting oil and gas and investing in solar or wind energy so you’ve still got some supply of energy when the fossil fuels run out. But it doesn’t have to be a direct substitution. One of my friends loves to argue for taking some of the money you get from oil and gas revenue and investing it in early childhood education – building up human capital. Here’s the OECD definition for weak sustainability:

All forms of capital are more or less substitutes for one another; no regard has to be given to the composition of the stock of capital. Weak sustainability allows for the depletion or degradation of natural resources, so long as such depletion is offset by increases in the stocks of other forms of capital (for example, by investing royalties from depleting mineral reserves in factories).

Texas is not the sort of place where you think of sustainability as a guiding policy, but while they likely would flee from such a greenie-sounding label, that appears to be exactly what they’re doing to fund improved water infrastructure, Brett Walton reports:

Last year, lawmakers created a $US 2 billion water fund with surplus money from oil and gas revenues. Low-interest loans from the fund will finance both water-conservation initiatives and water-supply projects that are included in the state’s $US 53 billion water plan.

Famiglietti on draining the global groundwater bank

Dry season water storage anomalies in California, courtesy Jay Famiglietti/NASA/Nature

Dry season water storage anomalies in California, courtesy Jay Famiglietti/NASA/Nature

Jay Famiglietti in Nature Climate Change (paywalled):

The irony of groundwater is that despite its critical importance to global water supplies, it attracts insufficient management attention relative to more visible surface water supplies in rivers and reservoirs. In many regions around the world, groundwater is often poorly monitored and managed. In the developing world, oversight is often non-existent.

The result has been a veritable groundwater ‘free for all': property owners who can afford to drill wells generally have unlimited access to groundwater. Some countries, such as India, for example, even subsidize electricity costs for pumping to encourage greater agricultural productivity at the expense of falling aquifer levels.

Dr. Famiglietti offers some policy recommendations:

  • Ag efficiency: “Even modest gains in agricultural efficiency will result in tremendous volumes of groundwater saved”
  • Better data on how much water is actually down there: “the absolute volume of groundwater residing beneath the land surface remains unknown” (Michael Campana is sure to love this one.)
  • Conjunctive management of surface and groundwater
  • Better measurement and reporting of groundwater levels, especially across boundaries

Stuff I wrote elsewhere: septic systems and groundwater contamination

I am endlessly fascinated (and frustrated) by the mess that is societal risk perception. Here (behind a Google survey wall), a look at efforts to regulate septic systems in Bernalillo County, primarily on the kind-of-rural fringes of the Albuquerque metro area:

As groundwater contamination problems go, the stuff leaking from septic systems isn’t terribly sexy. Give me a gas station’s leaking underground storage tank any day, or an old electronics plant, or Kirtland Air Force Base’s sloppy aviation fuel handling. That I can get excited about.

But waste leaking from an aging home septic system?

That, says University of New Mexico engineering professor Bruce Thomson, is precisely the problem.

“It’s groundwater contamination that’s happening all around us, and we’re not paying any attention,” said Thomson, an expert in treating human waste who delights in describing his academic specialty as “turd mechanics.”

Dry start to southwestern U.S. 2014-15 water year

PRISM October '14

PRISM October ’14


Most of the way through October, it’s been a dry start to the 2014-15 “water year”, the season in which we build the snowpack to feed the rivers of the southwestern United States. As Jonathan Overpeck says:

Wells on the fringes of Tucson running dry

Contra Porterville in California, where poor farmworkers with few options are running out of water, on the fringes of Tucson it’s those who chose to sprawl onto the edge of a relatively affluent community, beyond municipal utilities and dependent on a marginal aquifer, who are now seeing their wells running dry. Tony Davis:

In the Tortolita foothills, Glenn Phillips has plenty of competition for water. About 70 wells, drilled since the early 1980s, are registered with the state water department in a one-mile-wide swatch north of Cougar Canyon Trail, between Como Drive on the east and Seifert Estates Road on the west.

They range from 150 to 1,250 feet deep, with bedrock less than 400 feet.

One of the area’s first wells was dug in 1979 by Charles Hill, now 61, whose home now backs up against Phillips’. A computer scientist who designs and writes applications for computers at the University of Arizona, Hill and his wife moved here from Tucson three months after their marriage because they wanted to live under dark skies and see the stars.

A Boulder Dam anniversary

Yesterday was the 78th anniversary of the first electric generator go into full operation at Boulder Dam. EDN has the story:

Electricity from the dam’s powerhouse was originally sold pursuant to a 50-year contract, authorized by Congress in 1934, which ran from 1937 to 1987. In 1984, Congress passed a new statute which set power allocations from the dam from 1987 to 2017. In December 2011, President Barack Obama signed legislation extending the current contracts until 2067, after setting aside 5% of Hoover Dam’s power for sale to Native American tribes, electric cooperatives, and other entities. The new arrangement will begin in 2017.

The dam, now named “Hoover”, also stores water to grow alfalfa and other things.

Priority administration and Arizona’s Colorado River allotment

It’s generally more complicated than I think:

Central Arizona Project priorities

Central Arizona Project priorities

A member of the Inkstain brain trust points out two catches in my “why can’t Phoenix just leave its unused apportionment in Lake Mead” post last week.

The first has to do with Arizona’s application of the doctrine of prior appropriation with respect to its allocation of Colorado River water delivered through the Central Arizona Project.

As shown in the diagram above, CAP water is stacked in priority first to meet Native American water rights, then cities, then ag users, and then “excess” and groundwater recharge. Under the doctrine of prior appropriation, if a “senior” user doesn’t use water, it’s then available to “juniors” like Central Arizona Irrigation and Drainage District in Pinal County, which last year got 124,369 acre feet of CAP water. And storing water in Lake Mead, my brain truster argues, doesn’t count as a “use”, so I guess it’s not the simple accounting exercise I thought.

Second, what Phoenix wants to do not would not qualify as “Intentionally Created Surplus” water even if Phoenix was a direct Colorado River federal water contractor and therefore eligible for the ICS program. ICS is a legal widget in which basin water users conserve water by, for example, fallowing land or lining canals and then bank the water in Lake Mead. I had suggested in my earlier post that what Phoenix wants to do in leaving its unused apportionment in Mead is kinda like ICS, but clearly it’s not. Even if Phoenix was a contractor, what it wants to do wouldn’t qualify as ICS because it’s not water once used and then conserved (a la fallowing).

The notion of Phoenix storing unused apportionment in Mead still could be a good thing, but the details are more complicated than I thought.