US, Mexico pact on Colorado River water

A number of news outlets (including ASU’s Cronkite News Service!) have reported on the agreement between the Metropolitan Water District of Southern California, the Central Arizona Water Conservation District, and the Southern Nevada Water Authority and one of their Mexican counterparts. The five-year agreement includes a one-time allocation of almost 100,000 acre-feet of water to the three US-side agencies, in return for $10 million that the Mexican agency will then use to repair irrigation infrastructure damaged in a 2010 earthquake. The three US water managers, which will split the allocation according to the amount of cash they’re contributing to Mexico, will store the water in Lake Mead for the time being.

The new agreement (called Minute 319 by the Department of the Interior) further includes an ongoing provision of Minute 318, which allows the Mexican agency to store water in Lake Mead during disruptions in its water-delivery infrastructure, or if it isn’t needed.

In addition to the direct economic benefit to both parties, the agreement will increase the amount of water in Lake Mead, which is great for recreational users, and it includes a provision to improve flows at the Colorado River’s delta. Look for a post describing the delta’s history and current conditions in the future.

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Water Conservation in AZ


Among the various water conservation efforts in Arizona is the Water – Use It Wisely campaign. This educational resource advertises on a number of outlets, directing water users to its website, The advertising and outreach are funded by a variety of water suppliers, from  cities (including Phoenix, Mesa, and Glendale) to private water companies, to the Salt River Project.

Water – Use It Wisely’s website includes a number of tips of its own, as well as a plethora of links to other water-conservation resources. One of the site’s features is a quick-and-easy Home Water Audit, which allows residents to calculate a numerical score between 0 and 36 based on how often they use residential best practices.

Another set of information that Water – Use It Wisely provides is a list of municipal Xeriscape Demonstration Gardens that include addresses and a few pictures of municipal parks or other public parks that have water-conserving landscaping. In Tempe, the Tempe Woman’s Club Park is also the city’s Xeriscape Demonstration Garden, and the Parks Department collaborates with the Water Resources Division of the Water Department to ensure that the park’s landscaping conserves as much water as possible. Visitors to this park won’t find any of the grass or Chinese Elms often found in other Tempe parks. Instead, the park is exclusively paved with gravel, and filled with Palo Verde and other desert flora.

Xeriscape Demonstration Garden

A Palo Verde is in full bloom in this undated photo at Tempe’s Xeriscape Demonstration Garden.

Tempe, along with Water – Use It Wisely, hope that these gardens will encourage people to convert their lawns (and deciduous, drought-intolerant trees when possible) with a more xeriscape-style landscape to conserve water. New home construction in Arizona often includes landscaping that uses less water, but whenever a water provider can convince a homeowner to convert to xeriscaping, the water provider gets more water to sell to another user.

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Fresh water – why not make more?

Fresh water is scarce in Arizona, and around much of the globe. Ocean water, however, is plentiful. Why can’t we make ocean water into fresh water?

Aerial View of the Yuma Desalting Plant Complex

Aerial view of Yuma Desalting Plant Complex from the Bureau of Reclamation’s website

The short answer is economics. There are two primary methods of removing salt from water. One is to heat the water, evaporating it into steam, which doesn’t contain salt. This is very energy-intensive. Wikipedia says that a typical nuclear-powered aircraft carrier in the US Navy uses a form of this method to distill 400,000 gallons of water every day.

The other method is to filter the water through a series of semipermeable membranes – often reverse osmosis. This method uses far less energy, but the membranes are still expensive, and often require lots of maintenance.

In much of Arizona, the soil contains lots of salt. This means that even rainfall that runs across the soil might absorb enough salt to make it unsuitable for many uses. Desalination efforts in Arizona have focus on runoff or groundwater that is too salty to use.

The Yuma Desalting Plant, or YDP,  was completed in 1992 at a cost of $250 million to deliver fresh water down the Colorado River to Mexico. It was intended to use “saline agricultural return flows” (runoff from the area’s irrigated farms) to fulfill the US’ legal obligation to Mexico (more on international water rights in the future). Due to high flows on the Colorado, it was only operated twice before 2010, when a Pilot Run was undertaken by the Bureau of Reclamation and several water districts and non-governmental organizations.

The Pilot Run, which wrapped up in July 2012, was an operational success – the aging plant apparently runs more efficiently than anyone had anticipated, at least with reduced energy and chemical costs due to the recession. This does not make it an economic success, however. Water resource managers (Central Arizona Project,the Metropolitan Water District of Southern California, and Southern Nevada Water Authority) in the Lower Colorado River Basin who are currently releasing enough water from Lake Mead to Mexico must decide. Would they rather pay millions of dollars to keep water in Lake Mead for their purposes and treat brackish runoff to send to Mexico? As flows in the Colorado River continue to fluctuate, this question will only become more urgent.

Alternatives include purchasing water rights from Lower Colorado farmers, effectively retiring farms. Look for a future post on this topic.

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El Nino forecast for 2012: Neutral/Weak El Nino

Sea Surface Temperature for 9-26-12

Sea Surface Temperature Anomalies for 9-26-12 – from the Climate Prediction Center

The Climate Prediction Center continued its forecast for a weak El Nino or neutral conditions this winter, based on barely above-average temperatures observed in the Pacific. The analysis notes that it’s possible that El Nino conditions could strengthen in the next few months.

The Arizona impact of this is that Arizona’s winter weather conditions are likely to be influenced by El Nino conditions in a very minimal way. This doesn’t mean winter precipitation in Arizona will be near-average, however. ENSO (El Nino – Southern Oscillation) conditions are only one factor that might help predict the amount of precipitation across Arizona. ENSO-neutral conditions basically tell us that precipitation (as well as temperatures) in Arizona could be less than, at, or above average, depending on other factors.

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Coverage of Arizona Snowbowl’s Use of Reclaimed Wastewater to Make Snow

Snowbowl August 2010

Snowbowl’s main Agassiz lift in August, 2010

With the (gradual, certainly in Phoenix) advent of Autumn, some people think of snow skiing. I stumbled across a blog post blandly announcing that Snowbowl’s artificial snow-making system, based on treated effluent, was nearing completion. I wanted more information. Mere days later, an article ran in the New York Times, with the word “sewage” in the headline. I thought, really? We’re still referring to reclaimed water as “sewage?” I still wanted more information. The Wikipedia page seems to cover Snowbowl’s basics, by the way.

The Times headline seemed to focus on the gross-out factor rather than the religious significance of the mountain, but the article itself puts the emphasis on the Native American communities (primarily the Hopi and Navajo, apparently) that hold the mountain sacred.

Some background: The ski resort in the past had a Forest Service permit to operate on 727 acres, which was expanded to 777 acres in 1992. In 2005, the Forest Service approved snow-making, based on treated effluent (“poop water”). There were also a number of other upgrades approved, including more lifts, hiking trails, a reservoir, 14 miles of pipe, expanded parking, and more.

This isn’t the first ski resort to propose making snow from treated effluent. Mt. Buller, a few hours from Melbourne in Australia, supplements water it draws from a nearby creek with treated effluent to make snow. Meanwhile, in the US, the EPA and Arizona Department of Environmental Quality certify that wastewater treated to certain standards is safe for making artificial snow. Some environmental groups, including the Sierra Club, dispute this analysis.

As another aside, Flagstaff and many other communities around the US have been using treated municipal wastewater for many uses, including landscape irrigation. These uses have been largely accepted by many communities in recent years. The NOAA does acknowledge that persistent pharmaceuticals in the water and runoff (it calls them “biologically active”) may have an impact on various fauna, and is attempting to monitor it.

In this context, headlines like the Times’, or Mother Jones’ “Sewage Snow: Coming Soon to a Slope Near You?”, or Fast Co Exist’s “Don’t Eat the Yellow Snow” and many more seem like the worst kind of attention-seeking editorial excess. The Times article quotes a scientist, Catherine R. Propper, who says that “a mouthful of snow is not going to make the difference.” Snowbowl’s FAQs state that you don’t usually want to eat any snow at a ski resort, for a number of reasons. The “gross-out” factor is simply unnecessary in coverage of this issue, particularly in such an obvious ploy to grab eyeballs (on the other hand, it worked on me).

The real issue here are the Native American people, who feel that they are being marginalized by the expansion of the resort, with the addition of treated wastewater a symbolic and grave insult added to injury. Snowbowl should switch to potable water for snow-making and other uses on the mountain, and Flagstaff should find other winter customers for its treated effluent.

Meanwhile, I’m curious to learn the effects of persistent pharmaceuticals in otherwise clean treated effluent. I’ll ponder this question during my favorite Snowbowl activity: riding the ski lift during the summer months.

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The Arizona Canal

Arizona Canal at dusk

Arizona Canal near Glendale Avenue around dusk on September 22, 2012.

The Arizona Canal runs roughly west in Phoenix, farther north than any other canal in the Salt River Project’s system. It has a number of recreational, artistic, and other attractions along its length, but Phoenicians still haven’t attempted to make it a focus of their city, unlike San Antonio’s Riverwalk. See for one group’s description of what such a focus might look like for Phoenix.

In the meantime, the Arizona Canal delivers water to users throughout the area, and access roads along its banks provide bikers, runners, dog-owners, and many others with a smooth, level path that stretches for miles.

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On stream preservation and the open market

I stumbled across this TED talk recently – it’s very short on specifics, but delivers a great message in a compelling way (which are characteristics of any good TED talk, coincidentally). Enjoy!

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