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Amid drought, Phoenix plans for a future with less water

As the Colorado River’s flow declines, water supplies in seven states are imperiled by potential shortages. That includes Arizona, which passed legislation outlining steps it would take if water from the river continues to decrease. But what does a water shortage mean for Phoenix? Hari Sreenivasan reports. This story is part of our series, “Peril and Promise: The Challenge of Climate Change.

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  • Hari Sreenivasan:

    This past winter the state of Arizona passed a key piece of water legislation. It's called the drought contingency plan and it acknowledges the fact that the Colorado river is providing less water than it used to to the seven states that depend on it. In fact, places that rely on the river are now facing a looming shortage. We traveled to Phoenix to find out how the growing city is preparing for a future with less water.

    This story is part of our ongoing series Peril and Promise: The Challenge of Climate Change.

    Arizona is in it's 19th year of drought. But walking around the more than 400 acres of the Tres Rios wetlands just outside Phoenix, you'd be hard pressed to find any evidence of that.

    150 different species call this place home for at least part of the year. There's lush native vegetation, large ponds, and water rushing through man-made tunnels.

    So how is this wetland staying wet?

  • Kathryn Sorensen:

    We've been reclaiming and reusing our wastewater for about 40 years now.

  • Hari Sreenivasan:

    Kathryn Sorensen is the director of Phoenix's Water Services Department, which delivers water to about one point five million people. After it's used some of it ends up here at Tres Rios.

  • Hari Sreenivasan:

    And what percentage of your overall water from Phoenix is recycled so to speak?

  • Kathryn Sorensen:

    Actually all of it. So all the wastewater that's generated here in the city of Phoenix gets reclaimed and reused for one purpose or another.

  • Hari Sreenivasan:

    Phoenix's wastewater is treated at plants like this — there are two of them in the area. This site releases about 53 million gallons of newly cleaned water a day into this constructed wetland system.

    The series of ponds helps "polish" or reduce chlorine levels in the water before it's pushed into a nearby river. The city sends more than 23 billion gallons a year of recycled wastewater to a nuclear power plant. An additional 16 billion gallons a year are used to irrigate nearby crops.

    This water recycling effort is part of Phoenix's larger strategy to secure long-term access to water. To achieve that, this desert city is counting on water storage and conservation.

  • Kathryn Sorensen:

    The thing about Phoenix is it's hot and dry here. It's always going to be hot and dry here, right. We want people to save water because they live here, because it's part of embracing a desert lifestyle.

  • Hari Sreenivasan:

    Drive around the city, you'll see the conservation efforts from one front yard to the next. These gardens require little or no water. We did come across lush landscaping and lawns being doused, but Sorensen estimates that only about 14 percent of homes have grass today, down from 80 percent in the 1970s.

    She cites not only water conservation campaigns but also the cost of water as two of the biggest reasons for the change. Since 1990 the city charges ratepayers a 28 percent premium for water in the summer when demand is highest.

    And Phoenix's efforts at conservation are paying off.

  • Kathryn Sorensen:

    We use less water today than we did 20 years ago but we serve 400,000 more people with that same amount of water.

  • Hari Sreenivasan:

    Those savings are crucial for a growing desert city with mounting pressure on it's water resources.

    Phoenix is served by three rivers — the Verde, the Salt and the Colorado. The Colorado, which originates from snowpack supplies Lake Mead. It's America's largest reservoir and provides about 40 percent of the city's water. But that source is under threat.

    Over the past century the Colorado River's flow has declined by about 16 percent. Scientists point to climate change as a main reason. A warming environment means less snowpack and less water in the river. They project even greater losses over the next 50 to 100 years.

    This means less water in Lake Mead. Levels have dropped 120 feet over the last 20 years, and the federal Bureau of Reclamation is projecting a shortage as soon as next year.

  • Kate Gallego:

    We are very aware that climate change is happening, that we have increased risk of drought and also that more of our precipitation is going to come in shorter, more intense events.

  • Hari Sreenivasan:

    Kate Gallego is the recently elected mayor of Phoenix.

  • Hari Sreenivasan:

    You get a good chunk of your water from the Colorado River and there's a lot of concern that those levels at Lake Mead are going down further and further beyond what people were expecting. What happens to Phoenix's water supply if the Colorado stops giving?

  • Kate Gallego:

    We are incredibly linked with the Colorado River and it has been declining at Lake Mead at a faster rate than we expected. We're trying to think long term. So we are storing more water and investing in infrastructure to be able to get that out.

  • Hari Sreenivasan:

    For more than 20 years, Arizona's water storage agency has been saving the state's unused Colorado River allotment in underground aquifers. It now has about half a year's worth of water that can be shared with cities including Phoenix should there be a water shortage.

    Building on this idea, Phoenix has struck its own separate water storage agreements with other Arizona cities.Take its arrangement with Tucson. Phoenix uses only ⅔ of the water it is entitled to from the Colorado River. So it stores up to 12 billion gallons of water every year in Tucson's aquifers. Tucson can then use that water when it faces a shortage. In exchange, Phoenix will get to use future Colorado River water that is allocated to Tucson.

  • Kathryn Sorensen:

    So we go out and acquire supplies every chance we get. We make sure we have a diverse basket of them. More than we need today to meet our demands so that we can provide for the future.

  • Hari Sreenivasan:

    That sometimes means paying partners to conserve water.

    Have you in your lifetime seen this river flowing?

  • Stephen Lewis:

    Very rarely.

  • Hari Sreenivasan:

    Stephen Lewis is the governor of the Gila River Indian Community. The reservation is just south of Phoenix and home to the Akimel O'otham and Pee-Posh tribes.

    Decades of upstream water diversions left this three mile stretch of the Gila River dry until just a few years ago. Negotiations between the community, the federal government and Arizona to provide water access led to the restoration of tribal water rights and paved the way for this renewed river flow.

  • Stephen Lewis:

    This is a working aquifer. It recharges water which builds up our groundwater supplies but also this allows us to use our Colorado River water for conservation purposes.

  • Hari Sreenivasan:

    The community now uses or stores its full allocation of Colorado River water in underground aquifers. But in 2017, Phoenix and several other partners paid the community 12 million dollars to leave some of its water in Lake Mead. This pay-to-conserve transaction is called system conservation.

  • Kathryn Sorensen:

    Essentially you find someone who's willing to use less water someone compensates them for using that that less water. The water though that's saved it doesn't belong to anybody. It belongs to the system. That's why it's called system conservation. It stays up in Lake Mead and just helps boost reservoir levels for everyone who depends on that water.

  • Hari Sreenivasan:

    Phoenix is also partnering with environmental organizations to maintain levels on the Salt and Verde rivers, two bodies of water that supply the city. An hour and a half north of Phoenix in the rural town of Camp Verde we met up with Kimberly Schonek.

    She works for the nonprofit Nature Conservancy managing projects along the Verde River.

  • Kimberly Schonek:

    So what we want to do is create a collective where people can invest in their watershed and benefit their water supply. So our partnership with the city of Phoenix is really about making that change and bringing this notion that downstream water users depend on watershed actions and improving watershed condition improves the resiliency of your water supply.

  • Hari Sreenivasan:

    Phoenix is contributing hundreds of thousands of dollars over the next few years to resiliency projects here. It is the first city in Arizona to do so, supporting projects like forest thinning that decrease sediment flow into the Verde River after wildfires.

    Funding from Phoenix also helps build on projects the Nature Conservancy has been managing for years like automated water diversions, or headgates.

  • Kimberly Schonek:

    So the headgates are control structures that are designed to regulate the flow in the ditch so that you have the amount of water that you need and want and leaving the rest in the river. So some ditches have cut their use by 25 to 40 percent just by implementing this very simple technology.

  • Hari Sreenivasan:

    More water left in the river by upstream users means downstream cities like Phoenix have more in the future.

  • Kimberly Schonek:

    And then this is a valve so you can see one of the issues with flood is just leaking.

  • Hari Sreenivasan:

    Another measure that benefits Phoenix's water supply, in 2015 the nature conservancy started working with farmers to convert from flood irrigation — which involves releasing water onto a field, to drip — which applies water more directly onto roots.

  • Kimberly Schonek:

    We're reducing their water use by 30 to 40 percent. So that has a huge impact on the river.

  • Hari Sreenivasan:

    But if investments, conservation and water agreements fall short, Kathryn Sorensen at the Phoenix Water Department says the city has a backup plan.

  • Kathryn Sorensen:

    The groundwater beneath us, the most recent estimate I got from the Arizona Department of Water Resources is that there's is 90 million acre-feet.

  • Hari Sreenivasan:

    That's 300 years worth of water for Phoenix. But accessing that water will require a significant investment — an estimated 500 million dollars to dig deep, expensive wells and install pipes to carry water to areas that may be cut off in the future.

    In January, the city council approved a rate hike that would help fund the new infrastructure. Its an investment against a warmer future that the city knows is coming.

  • Kathryn Sorensen:

    Oddly I think that that Phoenix is better positioned to deal with climate change than a lot of other cities across the country and the world. I know that sounds strange but I think we're just, we're always in the trenches here, we are always in the trenches. It is always hot and dry here and preparing for a future where it's going to be hotter and drier. We know how to do that.

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