We need to come to terms with the fact that we’re using less water

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tl;dr Western water policy and politics has to come to grips with the fact that overall water use is declining, not rising, as populations and economies grow.

The longer version….

Looks can be deceiving.

Two years ago, when I was deeply immersed in the act of writing my book, I had an incredibly important conversation with Emily Turner, my Island Press editor. I’d been sending her draft chapters and, in the way of the best editors, she offered a gentle insight into something I was doing that I hadn’t seen myself.

One of the keys to successful communication, in any form or forum, is to try your hardest to understand what the people you’re communicating with already know or think about the topic at hand. What Emily saw me doing, without realizing I was doing it, was repeatedly addressing the beliefs/ideas/expectations I expected my audience to hold – starting with what they knew or believed and heading off from there into new territory. Over and over, she saw me debunking what I thought were myths.

My very particular memory of that conversation includes an embarrassingly theatrical detail of where it took place – sitting in a room at the Planet Hollywood mega-casino/hotel in Las Vegas, looking out the window at the fountains of the Bellagio. The myth was that Las Vegas was on an inevitable trajectory to outgrow its water supply. The reality was the conservation was more than offsetting population growth, with no end of either trend in sight.

Here’s how that ended up looking in my book:

Despite the rhetoric of imminent doom, the math is inescapable. From 2002 to 2013, the greater Las Vegas metro area grew by 34 percent to a population of more than 2 million people. During that same period, its use of Colorado River water—its primary source of supply—dropped by 26 percent.

Las Vegas was not a cherry-picked exception here. I chose it carefully as a case study for my book because it is representative of what is happening across the West.

The year since the book came out has been a remarkable experience, as I’ve traveled the West watching my ideas interact with the world. In dozens of public talks, I’ve had a similar experience – I throw up a few slides with graphs of the decline of water use in Las Vegas, and Phoenix, and Albuquerque, and Las Vegas, and Phoenix, and Yuma, and Imperial, even as population and economic productivity grow – and the common response is, “Wow, really?” Followed by the questions. The most common audiences have been water wonks, but these discussions often (as often as I can make them) include water-concerned non-wonks as well.

I was thinking about this challenge this morning when I read this in an otherwise great blog post from Michael Campana. He’s quoting here an anonymous correspondent, someone who obviously has thought a lot, and well, writing him about groundwater science and policy in New Mexico:

Water consumption will increase as long as populations and development increase, but water resources are finite.  It is inevitable that demand will exceed supply at some point.  To approach and manage that point in a sensible and equitable manner will require reliable data.  Long term data collection is needed to establish a historical baseline and emerging trends.

Yes, long term data is needed to understand trends, to make the best use of science to inform policy decisions about water. But one of the critical pieces of this is the need to understand that the data clearly points to the fact that water use is going down. In New Mexico, from whence Michael’s correspondent writes, water use peaked in 1995, according to the terrific USGS Water Use in the United States datasets.

Decoupling.

In response to my decoupling spiel, I have become accustomed to many common whadabouts:

  • What about this particular geography (say, for example, rural groundwater pumping in the southern San Joaquin Valley), or this particular category of water use?
  • What about St. George Utah? Isn’t their water use going up even as they want to take more water out of the Colorado River?
  • Yeah, but how long can that continue? Won’t conservation bottom out?
  • What about climate change? Won’t that continue to reduce available water supplies?
  • What about the non-rich parts of the world?

My answer to the whadabouts is generally, “Yup, that’s an important question.” Most do not yet have good answers. But it’s important to consider those as genuine questions, to be studied as we look at future water policy, not as reasons to simply ignore decoupling and continue to assert that water consumption will inevitably increase as long as populations and development increase.

Maybe in the long run they will, but that’s the question we have to ask, not an answer we can just assume.

Iron, plastic, and big pipe’s battle to replace your municipal plumbing

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Hiroko Tabuchi has a fascinating piece in this morning’s New York Times about a battle underway to determine whether gazillions of dollars in infrastructure spending to upgrade America’s municipal plumbing is spent on iron or plastic pipe.

It features a couple of issues I love to talk about with our University of New Mexico Water Resources Program students:

  • rent-seeking behavior
  • scientization

Because it is an area where decisions are made by governments, and therefore influenced by political processes, water policy is a classic playground for what economists call “rent-seeking behavior” – attempts by individuals or firms to profit by influencing government decisions in their favor, rather than by making products that consumers want to buy. Here’s Tabuchi:

How the pipe wars play out — in city and town councils, in state capitals, in Washington — will determine how drinking water is delivered to homes across America for generations to come.

This lobbying war is playing out via a classic case of “scientization” – attempting to win a battle by claiming the scientific high ground:

Plastics are an obvious replacement for the country’s aging pipes. Lightweight, easy to install, corrosion-free and up to 50 percent cheaper than iron, plastic pipes have already taken the place of copper as the preferred material for service lines that connect homes to municipal mains, as well as water pipes inside the home.

Still, some scientists warn that the rapid replacement of America’s water infrastructure with plastic could bring its own health concerns.

The “scientization” hypothesis would predict that those who favor iron for economic reasons (because they sell iron pipe!) are more likely to find the “plastic could bring its own health concerns” argument persuasive, while Big Plastic will raise concerns about the problems of iron pipe.

I’ll leave a reading of Tabuchi’s story as an exercise for our students, to see if the scientization hypothesis is supported.

New USGS data shows municipal water use, including in the West, continues to decline

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The latest USGS data on water use by U.S. municipalities shows a continued decline, despite a growing population. This not just a decline in per capita use, though it is that. But per capita use continues to drop faster than population is rising in most areas. Brett Walton has a nice summary of the findings, and the full datasets for 2015 are here (and here for past datasets, for you enterprising Water Resources Program students who want to dig in).

But, importantly, as Walton points out, this is not happening everywhere:

According to the USGS report, which uses data from state agencies and water utilities, per person water use increased in the states of Alaska, Colorado, Idaho, Louisiana, Utah, Virginia, Wisconsin, and Wyoming.

Most of these states are in the American West, and three are in the upper basin of the Colorado River, where there is strong debate about whether to increase water withdrawals from the shrinking river.

This is interesting. In the Lower Colorado River Basin – California, Arizona, and Nevada – water use is down. With the exception of New Mexico, in the Upper Basin it’s heading up.

Some highlights:

  • New Mexico, population rose 2 percent from 2010 to 2015, while water use dropped 10 percent.
  • Albuquerque, population rose 4.6 percent while water use dropped 10.8 percent.
  • Maricopa County (greater Phoenix): population up 9.3 percent, water use down 3.6 percent.
  • Clark County, NV (greater Las Vegas): population up 7.4 percent, water use down 1.6 percent.
  • Los Angeles County: Population up 9.7 percent, water use down 8.4 percent.
  • San Diego: Population up 14.1 percent, water use down 14.5 percent.
  • Salt Lake County: Population up 7.4 percent, water use up 33.3 percent
  • Washington County, Utah (St. George area, where Utah wants to build the new Lake Powell Pipeline to remove water from the Colorado River): Population up 12.4 percent, water use up 11.7 percent, and per capita water use a hefty 318 gallons per person per day (more than double Albuquerque’s).

When people have less water, they use less water

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Consumptive use of Colorado River water by the states of the Lower Basin (Nevada, California, and Arizona) is on track this year to be at its lowest since 1986. This graph, which I put together this weekend for a talk I’m giving at the Upper Colorado River Basin Water Forum at Colorado Mesa University in Grand Junction next week, seems pretty remarkable to me:

Colorado River water use, data courtesy USBR

That green Upper Basin line only goes out through 2015 (takes longer to get the UB data), but it’s telling a similar story – again, lowest since the 1980s. Upper Basin Colorado River water use peaked in the 4 million-and-change range in the 1980s and has stabilized.

My friend Scot looked at a version of this graph and immediately asked about population growth during this time, and it’s a good question, but I don’t have that graph yet so I just waved my arms and told him “It’s gone up a lot.”

We’re using less water because there’s less water to use (see science). But there’s been no apocalypse. People aren’t abandoning the region’s desert cities and moving to Cleveland. We’ve still got yummy Yuma lettuce on our winter burgers. We’re adjusting.

Notes on the data:

  • Dataset provide by the US Bureau of Reclamation a couple of years ago, and updated by me with most recent data from their various routine reports. The most recent few data points on each curve are thus preliminary, subject to data updating and validation.
  • As Eric Kuhn, who’s collaborating with me on this stuff, points out, the red Lower Basin line does not include use of tributary water in the Lower Basin, as for example the Gila in Arizona.
  • The graphs include reservoir evaporation. That matters or doesn’t, depending on the question you’re trying to answer, but the shape of the curves, and the story they tell, is basically the same.

“the Eden of all bass fishermen”

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One of my favorite bits of business that never made it into my Colorado River book was a late afternoon encounter at Lake Mead’s Boulder Harbor boat ramp with a guy named Scotty. I was thinking about Scotty when I came across the image below, in a 1946 Bureau of Reclamation report on the development of the Colorado River.

Lake Mead, Eden of all bass fishermen

The Colorado Basin’s big reservoirs are the best measurement of the health of the hydraulic system on which the region’s farms and cities depend. Two things govern how much water sits in a reservoir – how much nature provides upstream, and how much people remove for use downstream. In the spring of 2015, as I stood at the bottom of the Boulder Harbor boat ramp, that health was not good. Looking up an adjacent hillside, I could see the high water mark more than a hundred vertical feet above me. The lake’s surface elevation, 1,088 feet above sea level, was the lowest it had been in any February since the dam’s federal managers closed its gates and began filling it back in the 1930s. Across the Colorado River Basin, combined storage in Mead and the Bureau of Reclamation’s other reservoirs, which when full hold about four years’ worth of Colorado River flow, stood at just 49 percent.

Scotty moved to Las Vegas after a stint in the Coast Guard and found a nice career supporting the convention industry. He comes down to the lake nearly every week to fish or boat. It is easy for outsiders to get caught up in resentment of Las Vegas, with its “sin city” reputation for gaudy excess, and to question why such our precious water should be squandered on such frivolity. But it is important to remember the Scotty’s of the world. To paraphrase the late Nobel laureate Theodore Schultz, people like Scotty are no less concerned above improving their lot and that of their children than the rest of us.

It was early in the season – late February, still too cold for the bass to be biting – when we talked as he pulled his little aluminum fishing boat out of the water at Boulder Harbor, the nearest boat ramp to his home in nearby Henderson. Henderson is the closest community in the greater Las Vegas metro area to Lake Mead, a quick drive through a treeless desert pass along Las Vegas Wash, around the south side of what the locals call “Sunrise Mountain”. The mountain is part of a treeless desert ridge that separates Las Vegas from a constant reminder of its vulnerability to drought – the great emptiness of Lake Mead.

Sunset over Boulder Harbor, Lake Mead, February 2015

On the north side of the harbor, against a bank lined with the high marks of old shorelines created as the lake receded, a swarm of ring-billed gulls poked at the water. Scotty pointed to the dipping and diving birds and explained that it was an early sign that the shad, a small non-native fish, were spawning. The bass would soon follow, and fishing season.

Scotty could remember the full days. When he came to Las Vegas in 1997, Lake Mead was more than a hundred feet higher than when we spoke. Locals would drive out the dirt road at Gypsum Wash to a spot where you could jump off a cliff eight feet into water. It used to be a favorite spot for shoreline fishing. Today, the cliff is 80 feet above a sandy wash.

At least Boulder Harbor is still usable. Just up the road, Gail Gripentog-Kaiser, whose family has run marinas and other recreational facilities on the shores of Lake Mead since the 1950s, packed up their floating docks and restaurants in 2002 and moved them to deeper water. A sign on the old the old Las Vegas Bay Marina floating restaurant read “Horsepower Cove or Bust” as the elaborate floating armada squeezed out the narrow neck of Las Vegas wash for a safer harbor.

Recreation brings Scotty to the lake, and gives him a tangible understanding of its decline. But it is the reservoir’s role as water supply to his adopted home, not its recreational value, that gives him pause. Scotty goes on line and tracks snowpack in the Rockies, the same way the water managers do, and talks idly about building a pipeline to the region to bring water from someplace wetter. But he does’t have much hope for a solution. “The writing’s on the wall,” he said. “There’s nothing we can do.”

More evidence that climate change is reducing the Colorado River’s flow

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Scientists for many years have projected a decline in the Colorado River’s flow as a result of a warming climate. But it’s only in the last couple of years that we’ve begun to see evidence that this is already happening.

The system has a lot of natural variability, so detecting the relatively smaller impact of warming amid the ups and downs of “did we have a lot of snow this winter or not” is hard stuff. But as the warming grows, so does the impact, and so does the detectability.

The latest, the third such effort, from the USGS’s Greg McCabe and colleagues, found a 7 percent decrease in the river’s flow in the past three decades as a result of warming temperatures.

Additionally, warm season (April through September) temperature has had a larger effect on variability in water-year UCRB streamflow than cool season (October through March) temperature. The greater contribution of warm season temperature, compared with cool season temperature, to variability of UCRB flow suggests that evaporation or snow-melt, rather than changes from snow to rain during the cool season, have driven recent reductions in UCRB flow. It is expected that as warming continues, the negative effects of temperature on water-year UCRB streamflow will become more evident and problematic.

Precipitation, primarily winter snow, remains the dominant variable influencing the Colorado River’s flow. But for a given amount of snow, we’re seeing less water in the river, a decrease in “runoff efficiency”.

McCabe et al

The two previous papers that also showed this: