Lions, like water lawyers, are doing pretty well for themselves in the drought. Mostly for the same reasons. https://t.co/ktMC6TO1nZ
— WatergrlJD (@watergrlJD) March 13, 2016
Why lions can feast during a drought https://t.co/H7zc7fzsET
— PRI (@PRI) March 13, 2016
In a neat new paper looking at sediment layers near Blythe, California, Jordan Bright of the University of California and colleagues (paper here, $ gated) argue that they’ve found evidence of the moment (in geological time, the “moment” is really hundreds of years) when the Colorado River made its first dash to the sea.
The Blythe Basin, they argue, was a vast inland lake/sea thing, until the water finally busted through the “Chocolate Mountain paleodam” in what must have been an impressive geologic woosh:
We suggest that Blythe basin was filled with a hydrologically complex Colorado River-fed lake that was abruptly breached in an over-spilling event at Chocolate Mountain paleodam near its southern margin….
The work involved looking at isotopic changes in the composition of rock layers in Hart Mine Wash, which is on the Arizona side of the Colorado River about 15 miles south of Blythe. Their map of the hypothesized lake is really cool:
Regional map showing the relationship between the course of the modern lower Colorado River, Blythe basin (intermediate blue), basins to the north that contain the Bouse Formation (light blue), proposed paleodams (black bars with names), and the study location (solid black star). Numbers in parentheses denote highest elevation (masl) of Bouse Formation in the respective basins. Figure modified from image provided by R. Dorsey.
This month’s US Bureau of Reclamation reservoir forecast model runs show the implications of the warm, dry spring, with a drop of 620,000 acre feet and six feet in elevation in the estimated end-of-year storage in Lake Powell, the major reservoir in the Upper Colorado River Basin. Here’s my long term forecast graph, updated with the latest estimates through the end of water year 2017:
Colorado River storage
Tony Davis had a good story earlier this week discussing this year’s big snowpack fail:
The low expected runoff does not mean a shortage in deliveries of Central Arizona Project water for 2017 — at least not yet. The U.S. Bureau of Reclamation has predicted a very low chance of a 2017 shortage but forecast a greater than 50 percent chance of a 2018 shortage.
Haven’t seen the latest model runs yet, but I assume that 2017 shortage number is going up.
Brett Walton wrote a smart piece about the relationship between poverty, income inequality, and decaying US water infrastructure:
Affordable water requires an all-in effort that cuts across the political spectrum, a mix of redirected spending priorities, tax policy, social programs, and engineering assessments at the local, state, and federal levels. The urgency, experts assert, will grow, as water systems enter the Replacement Era — to use American Water Works Association’s phrase — while a high-tech economy widens the distance between the well-compensated haves and the struggling have-nots.
Brett Walton had a piece last week that suggested an appropriate damper for the US water community’s enthusiasm for the Obama administration’s recent Big Water Push:
The budget request drew praise from water experts, who, even with the small sum, were happy to see more recognition from the country’s leadership. But those same voices note that the most fruitful prospects for refashioning the country’s relationship with water are not technological. They are political: changing the laws, policies, and incentives that guide water use at the local, state, and federal levels. In other words, tinkering with the rules of the game, not just adding new pieces to the board.
“It makes sense to invest in research and technology,” Doug Kenney, director of the Western Water Policy Program at the University of Colorado, told Circle of Blue. “The key is that it needs to be balanced with policy changes. There’s nothing wrong with technology and research. But it’s the easy piece, I’m afraid.”
Connie Woodhouse at the University of Arizona and colleagues have a new paper presenting the most direct link yet between a greenhouse-warmed climate and reduced flows in the Colorado River.
Comparison of hydroclimatic variables (Colorado River at Lees Ferry water year streamflow, October–April total precipitation, March–July average temperature, and prior November soil moisture) averaged for the years in each of six droughts in the upper Colorado River basin, percentile values with standard errors. Woodhouse et al
Modeling has for many years projected such an effect in the future, but the new Woodhouse et al. paper (Increasing influence of air temperature on upper Colorado River streamflow, GRL, I believe it is ungated) is the first direct published measurement I’m aware of suggesting that it is already underway:
An important finding revealed by this work is the clustering over the last two decades of anomalous years in which already low flows are lower than might be anticipated given cool season precipitation totals. Drought conditions have persisted over the past 15?years in the upper Colorado River basin, negating any substantive positive effect of a handful of wet years (2005, 2008, and 2011) within this interval of time. In most recent drought years, low flows have been further exacerbated by warm temperatures. (emphasis added)
Woodhouse and her colleagues looked at a range of influences in annual flow on the river, including how much precipitation fallows, soil moisture in the preceding season, and spring-summer temperatures. They found that the drought of the 21st century was actually the wettest of the droughts in the historic record, as measured by the amount of precipitation falling across the Upper Colorado River Basin. But the extraordinary temperatures (it has been by far the warmest drought) pushed down the river’s flow.
This is scientifically unsurprising. When it’s warmer, plants transpire more water, and evaporation is greater. But there’s some subtle statistical analysis in the new Woodhouse et al. paper that goes beyond this obvious point to tease out the relationship between precipitation, temperature, and antecedent soil moisture. (One of the surprises to me was the relatively small impact of soil moisture going into the winter. I’d have expected the effect to be larger.)
Worth noting: the forecast this year is for a warm spring.
The March 1 forecast for the Rio Grande in New Mexico suggests we are heading into another dry year on the Rio Grande in New Mexico, with a median forecast of 80 percent of the 1981-2010 average flowing into Elephant Butte Reservoir. (source pdf)
Flow at Otowi, on the Rio Grande in New Mexico
That is close enough to average that there is a lot of room on the wet side of the probability distribution to yet have a wet year. But when I wrote that last sentence I chose “average” rather than “normal” with some care, because “normal” for the years since 2000 has been dry. The graph to the right is what is called the “Otowi Index Flow”, a measure of native Rio Grande water flowing past Otowi, the key measurement point in northern New Mexico for Rio Grande Compact compliance calculation. The horizontal line is the long term mean, going back to 1940. You can see that just two years since 2000 have been above that mean. If the March forecast holds, 2016 will be the eighth consecutive year below that mean. One expects high variability on this system, with a big gap between wet years and dry years.*
But eight consecutive dry years would be extraordinary. The previous longest runs were four consecutive dry years. Since 2000 inclusive, flows on the Rio Grande at Otowi have average 30 percent less than the 1940-1999 average.
* In statspeak, the “coefficient of variation”, the size of the standard deviation relative to the mean, is 54 percent, which is big. By comparison the Colorado River at Lee’s Ferry has a coefficient of variation of 29 percent. The Mississippi at St. Louis is 34 percent.
WILLOW BEACH, ARIZ. – One of the things I miss about my newspaper life is the quiet pleasure of a cool dateline, dangling at the start of a story like a sparkle of anticipation. So grant me this one.
The snow goose of Willow Beach.
Willow Beach is a boat landing and picnic spot at the bottom of Black Canyon on the Colorado River, 13 river miles downstream from Hoover Dam. It’s not so much a river here as a narrow lake, “Lake Mohave”, which backs up behind Davis Dam. Mondays and Tuesdays are “no motor” days, so you can paddle upstream through Black Canyon toward the base of Hoover Dam without the noise.
Walking downstream from the boat ramp I came upon a snow goose, up out of the water, looking quite alone. You never see snow geese by themselves – they’re serious flockers. My bird book and a search of eBird reports suggests it’s not that common here. Its effort to flee my presence seemed pretty lackluster, so I suspect it was sick. Bird rarities can be great for list-keeping (it was my 100th Arizona life bird) but they’re always sad to me.
Willow Beach is a pretty spot, but strange. The water here is a rock solid 55 degrees, cold by desert standards, because the Hoover Dam power plant intakes are deep in Lake Mead. So what we have here is far from “natural”. It lacks the annual flood cycle you would have had before the dam was built, it’s slow and easy, and really cold. The coots and ring-billed gulls don’t seem troubled – hundreds of each. Nor did the dog jumping in and out of some guys’ canoe.
But this is a very different Black Canyon than the one Joseph Christmas Ives powered up in his steamboat in 1858.
I’ll be at the Nevada Water Resources Association meeting in Las Vegas next week, talking Wednesday morning about what we need to do to avoid running out of water. If you’re there, say “hi”.
Courtesy City of Pasadena
Pasadena, a suburb of Los Angeles, is in the hunt for more water:
A recycled water project started in 1993 moved forward Monday night as the Pasadena City Council approved the environmental review of a plan to funnel water from Glendale.
The $50 million project could take 20 years to complete, with a pipeline running from a proposed reservoir in Scholl Canyon in Glendale to one at Sheldon Reservoir near the Brookside Golf Course. It would increase Pasadena’s local water supply by about 10 percent, officials said.
Pasadena, part of one of the earliest California efforts to regulate groundwater pumping, gets more than half its water from Metropolitan Water District imports, water from Northern California via the State Water Project and the Colorado River. The rest coming from the local groundwater basins. It’s always been of interest to me because it’s where I started writing about water in the late 1980s, as a newspaper reporter for the Pasadena Star-News.
Pasadena, Calif., water use, 1980-2015
When Emily Green this morning linked to Jason Henry’s story on the new Pasadena water plan, it prompted me to pull the latest data on the community’s water use. The results are unsurprising. Like nearly every community I look at, water use is down.
Since we left 25 years ago, Pasadena’s population has risen 10 percent. Its total water use has declined 29 percent. Per capita use is down 35 percent. Water use in 2015 was by far the lowest in the 35 years for which I have data.
This graph represents total water use, the combination of local groundwater and imported supply from Met.
You can see the big drop in 2015, as Southern California water users respond to the drought-tinged regional conservation initiatives. But even before that, Pasadena was part of the overall trend toward reduced water use in the metropolitan western United States.
Everyone’s using less water.