So did Lake Mead break the record yet or not?

At this point it’s just a parlor game, but has Lake Mead broken through the old “lowest since they filled it” record yet or not? Regardless of the fractions of an inch involved, it’s a big deal. (Go to Circle of Blue for an explanation.) But the conversation this week has been a bit confused about whether we’ve actually crossed this milestone or not.

Here’s how the Bureau of Reclamation put it in their official news release Tuesday:

BOULDER CITY, Nev. – Lake Mead, the reservoir created by Hoover Dam, is anticipated this week to reach its lowest water level since the lake’s initial filling in the 1930s. The Bureau of Reclamation’s Boulder Canyon Operations Office is projecting the elevation to drop to 1,081.75 feet above sea level during the week of July 7 and to continue to drop, reaching approximately 1,080 feet in November of this year.

The old “record” was set in 2010, when Lake Mead bottomed out at 1,081.85 feet above sea level in the 9 p.m. hour on Nov. 27 (source pdf):

Lake Mead's previous record, courtesy USBR

Lake Mead’s previous record, courtesy USBR

On Tuesday, the same day as the press release went out, Mead briefly dropped below that point, to 1,081.84:

With apologies to Emily Green, Lake Mead - Low Bad

With apologies to Emily Green, Lake Mead – Low Bad

But it didn’t last, popping right back up. Hydrologists at the Bureau point out that the levels were bouncing around quite a bit, and there was a storm in the area, so maybe it’s questionable data? We’re talking tiny fractions of an inch here, which is why this is just a silly parlor game. On Wednesday, it briefly got as low as 1,081.82 before popping back up.

July 9 Mead levels

July 9 Mead levels

On Thursday it hovered above the old “record” all day (and it rained!). Today, it’s still above the old record.

Isenberg: Drought amplifies, not causes, water problems

Smart words from Phil Isenberg, California’s water sage:

[O]ur historic population and economic growth—and the social and individual choices we have made—explain the water and environmental problems we face today. Unless we acknowledge that water supplies are limited, and act to temper our water use, we will limp toward the next drought, and act surprised when it happens. Matching human expectations to the limits of nature is essential, but generally not politically popular.

The clash here is between public expectation and hydrologic reality:

Most policy-makers, even lesser ones like me, want to find popular solutions to com- plicated problems. That’s why we spend so much time talking about “win–win” solutions; the dream world where everyone gets whatever they want, and there is no need for taxes or fees to pay for the result! Sure, this is completely unrealistic. We know that.

However, we also know that public expectations— unrealistic or not—permit or block good policy changes.

AMACRQ: Can you move Colorado River water from one state to another?

For the latest “Ask me a Colorado River question,” a friend of Inkstain wonders:

Q: Can you move water from one Colorado River Basin state to another?

A: No.

OK, this is the Law of the River, so of course it’s more complicated than that, with numerous edge case exceptions, but basically, no, you can’t move water from one Colorado River Basin state to another.

The 1922 Colorado River Compact divided what the framers thought was a reasonable estimate of the Colorado River’s flow in half. States of the “Upper Basin” – Wyoming, Colorado, Utah and New Mexico – get 7.5 million acre feet per year, and state of the Lower Basin get 7.5 million acre feet per year.

The Upper Basin states subsequently got together to split up their share on a percentage basis:

  • Colorado 51.75%
  • Utah 23%
  • Wyoming 14%
  • New Mexico 11.25%

The Lower Basin states fussed and feuded and finally the Supreme Court stepped in and said:

  • California 4.4 million acre feet
  • Arizona 2.8 million acre feet
  • Nevada 300 thousand acre feet

Each state then is left to its own devices to divide up its own share internally, based on its own internal water laws and politics. But one of those devices cannot be to buy some extra water from one of the other states.

The result is that, to the extent that we’re seeing innovative water sharing and transfer agreements, they all tend to happen within a single state.

In Arizona, for example, the Wellton-Mowhawk and Yuma Mesa irrigation districts are involved in deals that involve water conservation and transfer to urban water users. In California, the Palo Verde Irrigation District has a program in which land can be fallowed and saved water shipped off to Los Angeles. The Imperial Irrigation District has an agreement in which agricultural water conservation measures generate water that is then used by urban users in San Diego.

I say they all tend to happen within a single state, though, because there are interesting edge cases where boundaries are being tested. Nevada and Arizona, for example, have a program in which surplus Nevada water is banked in Arizona aquifers for later use. Complicated accounting swaps ensue through which, on paper, no water crosses state lines. Wink wink.

New Mexico is currently considering developing a New Mexico unit of the Central Arizona Project which would involved diverting Gila River water within New Mexico, before it gets to Arizona, and then (again on paper) swapping that water with downstream CAP water.

But the most interesting test of these boundaries is an effort currently under development that Henry Brean wrote about in May under which urban agencies across the basin would pool their resources to fund conservation programs (most likely ag conservation) somewhere in the basin. The saved water would simply stay in the river for everyone’s shared use – “system water”. The result is that water conserved in State A might then be used in State B, but no one’s accounting for it specifically. It’s a clever workaround.

So the answer to the original question is really, “Not exactly, but people are trying.”


Stuff I wrote elsewhere – the Cooper’s hawks of Albuquerque

From this morning’s newspaper, a column about a day with a research team studying the Cooper’s hawks that are making an increasingly comfortable living around my city:

Cooper’s hawks are primarily woodland birds, and we have built an expansive urban forest across the Northeast Heights. The urban neighborhoods on the east side of the river are older, and therefore their trees are more mature, making them a better “forest” for the birds, Madden suggested.

The urban forest also makes great habitat for smaller birds – sparrows, finches, robins and especially doves and pigeons. Cooper’s hawks especially love the doves and pigeons.

Lake Mead at 1,081.89 feet above sea level and dropping: Is this unprecedented?

update: With the latest hourly reading, the elevation of Lake Mead has dropped to 1,081.84 feet above sea level, the lowest it has been since the reservoir was being filled in the 1930s:

With apologies to Emily Green, Lake Mead - Low Bad

With apologies to Emily Green, Lake Mead – Low Bad

Previously: Last night at midnight, the surface elevation of Lake Mead dropped to 1,081.89 feet above sea level, half an inch above the previous record low of 1,081.85 set around 9 p.m. Nov. 27, 2010 (source pdf). There’s a certain ebbing and flowing as water flows in from upstream and flows out to run turbines and water downstream farms, so I can’t say with precision when we’ll break the old mark, but by some time tonight or early tomorrow, it’s likely to drop past the record.

This already generating a lot of attention, and is likely to generate more as the record is set. (I had to wait in line this morning behind a TV station when I wanted to talk to one of the key basin water managers. I am not in a hurry. I am writing a book, which has a looser deadline.)

One of the truisms you will likely hear is that the drought since 2000, which has contributed to Mead’s decline, is unprecedented, outside of the historical record and therefore something water managers could not have been expected to plan for. But I recently ran across an interesting graph from the Bureau of Reclamation that suggests that may not be quite right. If we take the estimated river flows of the drought conditions that spread across the Colorado River Basin in the 1930s and early 1940 and overlay them atop a 21st-century water management system, Lake Mead would actually drop faster than it is today.

Simulated Lake Mead levels, courtesy USBR

Simulated Lake Mead levels, courtesy USBR

Take a look at the blue line and circles in the graph to the right labeled “Trace 1″. (Click to blow it up if you need to, I can wait.)

This is from the 2007 Final Environmental Impact Statement for the Colorado River Interim Guidelines for Lower Basin Shortages and Coordinated Operations for Lakes Powell and Mead. (source) The hydrologists created a series of synthetic data series and plugged them into a modern river system operational model – dams, water users and all – to see what would happen to Lake Mead in the future under various inflow scenarios.

Look at how that blue “Trace 1″ line crashes beginning in 2031. That is a simulation of what would happen to Lake Mead if the drought of the 1930s-1950s was repeated in the 21st century. Under that scenario, it takes Lake Mead 14 years to drop from full to a surface elevation of 1,075. The current best estimates are that we could hit 1,075 in 2015 (source pdf), 15 years after it was last fullish in 2000. But what’s got to be unnerving if you’re a water manager is what happens to Trace 1 after it hits 1075. Under that historical hydrology, Lake Mead kept dropping for nearly a decade.

So what’s happening now is essentially equal to, but perhaps not worse, than, the worst case in the historical record.

Caveat: Here’s where the apples and oranges mix. The “Trace 1″ scenario, in addition to taking the historical hydrology, presumes some expansion of water use in the future. So by 2031, when Trace 1 begins its crash, there is perhaps ~250,000 acre feet of additional water use in the Upper Basin that is included in the model.

Jagger, Richards and Steinberg on the California water bond

California state senator Darrel Steinberg on the California water bond:

In the water world, you can’t always get everything you want, but there’s a whole lot in this bond that California needs.

Mick Jagger and Keith Richards on (I think) taking a lot of drugs and getting laid:

You can’t always get what you want
But if you try sometime you find
You get what you need

Characteristics of a good water policy solution

Helen Ingram and colleagues on a few necessary conditions for a good solution to water management issues:

Good policy design contributes to three key public needs: progress in problem solving that will make tomorrow’s challenges easier than today’s; representation of sufficient interests, so that the policy has a positive balance of support and is politically feasible; and empowerment of the people affected, so that they can become engaged and better able to resolve their own problems.

That’s from Divided Waters, the excellent 1995 book by Ingram, Nancy Laney, David Gillilan about the specific water management problems of the twin cities of Nogales in Arizona and Sonora, and about transboundary water management challenges more generally.

How much rain did Albuquerque get last night?

It’s monsoon season here in New Mexico, which means thunderstorms popping up here and there and, one hopes, everywhere around the state.

In my blog stats, I notice that around this time of year I frequently get traffic for people searching for things like “how much rain did Albuquerque get today”. I’m writing this as a sort of permanent archive, hoping that some of you will find it via the Google on days like today.

One of the problems with this question during the summer is the extreme variability of thunderstorm precipitation. You can get dumped on, and a neighbor a few blocks away can get very little. The best way to find out how much rain you got is to get your own rain gauge and join the CoCoRaHS network of volunteers. Info on signing up can be found here.

If you want to see what all the other CoCoRaHS volunteers reported, the site has frequently updated maps. If you click on the map on the bottom, you’ll get a Google map for the state and can zoom in and see the reports for your neighborhood. Albuquerque has a pretty dense network of volunteer observers, so it gives a nice look at the spatial variability of these storms. Lots of CoCoRaHS observers only report once a day in the morning, so it’s best for getting a “how much did it rain yesterday and last night” readout. It’s my favorite.

The National Weather Service reports data for the “official” Albuquerque rain gauge, which is at the airport. Given the spatial variability, this can be disappointing. (But it didn’t rain at my house!)

If you want to watch as the storm is in progress, the Weather Service radar page is great. Click on “1-Hour Total” and “Storm Total” in the left-hand rail to get the radar estimate of how much rain has fallen.