Resilience, and pulling the cap on the new Las Vegas Lake Mead intake

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Southern Nevada Water Authority crews pulled the end cap off of the agency’s new, deeper Lake Mead intake today, and by this weekend they’ll be pumping water from the new system. This is a major milestone in a system that, when completed, provides critical water management breathing room for the entire Colorado River Basin.

Las Vegas Lake Mead intake schematic, courtesy SNWA

Las Vegas Lake Mead intake schematic, courtesy SNWA

Theorists of “resilience” have adopted ideas from the study of ecology to what they call “social-ecological systems”. One of the critical elements is the idea of “regime shifts” – points in the evolution in the system at which change becomes sudden rather than gradual. A drought-driven forest fire is an example of a “regime shift”, or the sudden dieoff of fish once a river’s water temperature or flow levels cross a critical threshold. The water supply to the greater Las Vegas metro area is one such clearly identifiable scenario where a Colorado River Basin regime shift could happen. As the reservoir from which Las Vegas gets its water, Lake Mead, drops, there reaches a point at reservoir surface elevation 1,000 at which Vegas simply can no longer get water out of the lake. As the lake approaches 1,000, Vegas gets increasingly serious water quality problems, but at 1,000 it’s a city of 2 million people largely without water. “Vegas without water” is the sudden forest fire of the Colorado River Basin. As I’ve argued previously, this has little to do with the use of water by Las Vegas itself, which has become a water conservation model. Agriculture and cities downstream are responsible for most of Lake Mead’s decline. Las Vegas is, in some sense, vulnerable to the water use of others.

“protect elevation 1,000”

This has created an interesting dynamic in Colorado River Basin water management. This high risk scenario – a city of 2 million people losing 90 percent of its water supply – ends up driving everything else, removing management flexibility because of a need to, in the jargon of the water managers, “protect elevation 1,000”. The risk removes resilience by creating an unacceptable risk of regime shift. It also means that those other downstream water users in California and Arizona are vulnerable to Las Vegas’s intake problems, because there’s still a lot of usable water below 1,000 feet that they would not be able to use without drying up Las Vegas in the process.

Opening the new intake, an $817 million project, solves half the problem. But SNWA still needs to finish a pumping plant to take full advantage of it. That $650 million project is projected to be completed by 2020. This is cutting it close. The latest Bureau of Reclamation model runs suggested a one in 25 chance that Lake Mead would fall below elevation 1,025 by 2019, which is pretty risky territory when you’re betting the water supply of a metro area of 2 million people. But imagine the risk scenario if Las Vegas had not been willing to spend the $1.5 billion on the new intake system.

Met eyeing sewage recycling for Southern California supply

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Southern California water policy is looking like a game of speed chess right now. Amid the moves to supplement its Colorado River flow with extra water from Las Vegas and Imperial (agenda pdf), Met’s board also is considering spending money on cleaning up and reusing more of the sewage effluent Southern California currently dumps in the ocean. Here’s Matt Stevens’ take:

The Metropolitan Water District of Southern California is in talks with Los Angeles County sanitation districts about developing what could be one of the largest recycled water programs in the world.

In a committee meeting Monday, the agency’s staff presented the framework of a plan to purify and reuse as much as 168,000 acre-feet of water a year – enough to serve about twice that number of households for a year.

Doing so would require MWD to build a treatment plant and delivery facilities and comply with various environmental regulations. Officials say similar projects have cost about $1 billion.

Sewage recycling a shift?

Stevens and one of the board members he quotes call this a shift away from water importation for Met, but I’d argue that shift has been underway for nearly 20 years, since the development of Met’s “Integrated Resources Plan” in the mid-1990s. It was the IRP’s emphasis on more reuse, conjunctive groundwater management, and similar measures that positioned Met to successfully cope with the 2003 Department of the Interior decision to slash the agency’s Colorado River Aqueduct supplies. (Buy my book! As soon as I finish writing it! I’m almost done!)

But Southern California still dumps a lot of treated effluent into the ocean, so this option still leaves the region more room yet to move on the recycling front.

That time Lawrence Ferlinghetti visited the Salton Sea

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From the Paris Review, poet Lawrence Ferlinghetti’s journal of his 1961 visit to El Centro and the Salton Sea:

Even at the Salton Sea, the face of death has its smile. In the morning the wind is still blowing but the sun is bright, and life is stirring. Even at the bottom of a well, there’s life.

He took a bus, and seems to have left as quickly as he could, headed for San Diego. It does not sound as though he enjoyed San Diego either.

Despite drought, California farm employment rising

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I sometimes think that, in trying to understand the impacts of drought, we pay too much attention to the water numbers. It’s not that it doesn’t matter how much is in the reservoir, or is being pumped from the ground, but it’s only the first link in the chain of impacts.

California economist Jeff Michael points us to the Quarterly Census of Employment and Wages, which provides a relatively reliable and quick measure of employment impacts in the agricultural sectors, which is one area we would expect to see a societal response to drought. Here’s Jeff’s latest on the data, showing continued employment growth in California farm sector in spite of four years of horrendous drought:

For a number of years, the largest growth in farm jobs has been in the winter months rather than the peak summer months.  It suggests there is some restructuring going on in the seasonal patterns of the labor market, probably caused by the increasing number of permanent crops.  It could also reflect a tighter labor market which makes employers (in all industries) less willing to layoff workers during slack times.

What adaptive capacity looks like.

El Niño/Colorado River Basin update

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Since I wrote last month about the impact (or lack of impact) of El Niño on Colorado River flows, Paul Miller at the Colorado Basin River Forecast Center has done a new, more detailed analysis than the one I showed (which I had attributed to the Central Arizona Project folks, but which originally came from CBRFC):

Courtesy CBRFC

Courtesy CBRFC

The basic message is the same: the three strongest El Niño years have been wet, but that’s such a small statistical sample, and when you expand the universe to all El Niño years (the red ones on the graph above) you can see all kinds of scatter and pretty much zero statistical significance.

This is flow measured at Lee’s Ferry, the dividing line between the Upper Basin and the Lower Basin for purpose of Colorado River Compact administration. But Paul’s data got me curious. What about downstream of that point? Lee’s Ferry is the most important measurement point on the river, and the standard for this sort of thing. But flows below that point also are interesting, because the inflows downstream from Lee’s Ferry – especially the Virgin River and Little Colorado – are essentially “free water” for the Lower Basin when they are high and problem when they are low. And, in fact, El Niño years do show higher flows on this stretch of the river (warning: journalist doing his own math):

Impact of El Niño on Colorado River flow downstream of Lee's Ferry

Impact of El Niño on Colorado River flow downstream of Lee’s Ferry

This makes sense. The impact of El Niño is weaker as you go north, into the main part of the basin. But in the lower basin, especially Arizona, El Niño does tend to be wetter to the tune of about 170,000 acre feet per year compared to the long term average for the period I looked at.  I only calculated flows between Lee’s Ferry and Lake Mead, but river management folks say they also expect this downstream from Lake Mead, especially on the Bill Williams River. On average, this is enough to add a foot or two to Lake Mead during El Niño years. Not enough to make El Niño a drought mitigation tool, but a bit of potential good news for the Lower Basin.

(Note on data sources: El Niño comes from Klaus Wolter’s Multivariate ENSO Index, Colorado River flows from the USBR’s natural flow dataset. Period calculated: 1950-2012, because that’s the period for which the two datasets overlap.)

A promising seasonal forecast for the Colorado River Basin

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The federal Climate Prediction Center’s seasonal forecast, out this morning, looks promising for the Colorado River Basin:

November-January seasonal forecast, courtesy CPC

November-January seasonal forecast, courtesy CPC

These forecast maps can be visually deceptive. The greens mean a shift of odds toward wetter weather, not a forecast that we should expect wetter weather. Dice, loaded slightly in our favor. You can see all the precip maps here, which are showing odds tipped toward wet well into the spring across most of the basin, with especially strong odds of wetter weather in the southern part of the basin.

Just beware the risk (reality?) of warmer temperatures, which pose the risk of sapping river flows once the water hits the ground.