Plight of Phoenix: how long can the worlds 'least sustainable' city survive?

[nitpicker]

https://www.theguardian.com/cities/2018/mar/20/phoenix-least-sustainable-city-survive-water

Plight of Phoenix: how long can the world’s 'least sustainable' city survive?


Joanna Walters
Tue 20 Mar 2018 07.00 GMT

(snip)
To look around Anthem would be to imagine there is no such thing as a water shortage. But the lush vegetation and ponds do not occur naturally. Phoenix gets less than eight inches of rainfall each year; most of the water supply for central and southern Arizona is pumped from Lake Mead, fed by the Colorado river over 300 miles away. Anthem’s private developer paid a local Native American tribe to lease some of its historic water rights, and pipes its water from the nearby Lake Pleasant reservoir – also filled by the Colorado.

That river is drying up. This winter, snow in the Rocky Mountains, which feeds the Colorado, was 70% lower than average. Last month, the US government calculated that two thirds of Arizona is currently facing severe to extreme drought; last summer 50 flights were grounded at Phoenix airport because the heat – which hit 47C (116F) – made the air too thin to take off safely. The “heat island” effect keeps temperatures in Phoenix above 37C (98F) at night in summer.

(snip)
What these cities want is water. The Phoenix area draws from groundwater, from small rivers to the east, and from the mighty Colorado. The Hoover Dam holds much of the Colorado’s flow in the vast Lake Mead reservoir, but the river itself is sorely depleted. That water has now dropped to within a few feet of levels that California, Nevada and Arizona, which all rely on it, count as official shortages. Lake Powell, the reservoir at the other end of the Grand Canyon, similarly averages half its historic levels.

And yet despite the federal Bureau of Reclamation reporting in 2012 that droughts of five or more years would happen every decade over the next 50 years, greater Phoenix has not declared any water restrictions. Nor has the state government decided its official drought contingency proposal.
(snip)

[JNelson6563]

1. I hope they plan to

Go with desalination for ocean water. They may want to start looking into that soon.

[NNadir]

2. Phoenix is far from the sea, and desalination is energy intensive.

So is pumping water over mountains for hundreds of kilometers.

The closest outlet to the sea to Phoenix is in Mexico, in the Gulf of California, and I don't think pumping water under Trump's wall is going to be too popular in Mexico, and in any case, changing the Salinity of the Gulf of California, which has already been impacted by the fact that not a drop of water from the Colorado has flowed into it for decades, is going to be too popular with the Mexican people.

In any case, given that the fastest growing sources of energy on this planet are all fossil fuels, desalination is quite nearly literally pouring gasoline on the fire.

[CentralMass]

3. There is some research going on with graphene membrane filters that looks very promising.

http://www.bbc.com/news/science-environment-39482342

A crude description of it is that they are creating a fine sieve like filter of which the holes can be sized such that sodium chloride molecules can not pass through it when salt water is pumped through it. The technology requires much less water pressure the the current membranes being used for desalination. I've heard figures quoted like 80% less.

[paleotn]

5. Good idea....

but the ocean is still hundreds of miles away, with mountain ranges in between. We pump oil like that because of its high value per unit of measure. If we do that with water, only the relatively rich can afford it. The poor are just out of luck.

[CentralMass]

7. Yes, and we wouldn't want to pollute their oil fields with water pipeline spill.

[NNadir]

9. I've read quite a bit about membranes. They are not free energy.

The basic thermodynamics of seawater or any form of brine is that one needs to invest energy to overcome the entropy of mixing.

In the case of membranes, the energy consumed comes from pressurizing one side of the device; basically the energy comes from a pump.

The path may change the amount of energy that is lost to entropy, but it cannot eliminate it. The States of California and Arizona might try to repeal the 2nd law of thermodynamics, but the repeal will have no effect on physics.

Membranes foul, and this is a key element of membrane (and solid phase extraction) technology. There are ways to address this problem, but they are not simple and they all will have some environmental impact.

And then there is the matter of what to do with the salt that remains. While salt is a food, transportation and industrial commodity, the demand for it is not so high as to completely address the amounts that massive desalination would involve. This means that the salinity of ecosystems will be changed, resulting in significant damage to ecosystems or their complete destruction, as has happened in the Colorado delta, an ecosystem that has been completely destroyed, and saline concentrations are the reason.

[JNelson6563]

4. Then they should start packing.

[NNadir]

10. If I lived there I would. We had an outstanding member...

...here some years ago from that area, but I haven't seen him here for quite some time.

His comments would be interesting. He was quite bright.

[paleotn]

6. And we think Cape Town has problems....

Phoenix and Las Vegas could be twin disasters of biblical proportions in the coming decades. Future historians will marvel at our foolishness, and those cities may well become future metaphors for utter stupidity.

[ThoughtCriminal]

8. GOP controlled state is not only unprepared

They will continue to do the exact opposite of what needs to be done.

This is complete "Club for Growth" territory.