Karl Flessa will tell you that it's not that hard to collect seashells. All it takes is a bucket.
But the average beachcomber isn't bringing the specimens back to a lab to study population densities, reconstruct the salinity levels of the ecosystem and figure out how long ago the creatures that inhabited the shells were alive.
Flessa, the founding director of the University of Arizona's School of Earth and Environmental Sciences, has focused on the Colorado River delta since 1992. During his first trip there two decades ago, he found beaches made up almost entirely of mollusk shells—a result of the dry delta, which hadn't seen water from the river in years.
"The puzzle was that we couldn't find very many live individuals of the species that made those shells, and it was at that point we realized the environment had changed," he said. "What we were looking at ... was the remains of the former living community. That was a record of what the delta used to look like before upstream dams and diversions used up most of the water before it got to the gulf."
Though Tucson sits some 200 miles from the Colorado River delta, Southern Arizona's use of the river's water contributes to the drying of the region, and many question how long Arizona communities can rely on the state's share of it.
Recent reports from the Arizona Department of Water Resources predict a supply gap of roughly 1 million acre-feet by 2060—enough water for a million five-person families—thanks to population growth and climate change. But as the discussions about the water supply in Arizona continue, opinions vary among lawmakers, scientists and environmentalists on the next logical step.
Assessing the situation
In early April, 400 water experts from around the country packed a ballroom at the UA's Student Union. The conference, hosted by the university's Water Resources Research Center, served as a daylong think tank to address the supply gap that the state first announced in 2011. The gathering included representatives from water users' associations, the Arizona Department of Water Resources, Native American tribes and the Central Arizona Project.
Although speakers tossed in the occasional water joke, the attendees were serious about coming up with solutions. In an adjacent room, dozens of posters displayed various data that included crop patterns, water's effect on forest restoration and the anticipated water needs of Arizona's tribes.
Nathan Bracken, assistant director and general counsel for the Western States Water Council, sat on a panel that discussed the problems of water overuse and the benefits of reuse. Though the Southwest remains at the forefront of a possible water shortage, he said the region's problem is not unique.
"The Midwestern states that we represent have water-supply issues, too, but they have relatively more water, so it's not as acute there," Bracken said. "But even states like Kansas are looking very intently at this, and Oklahoma, too. Oklahoma is a very water-rich state compared to other Western states, but they have a goal now to make sure to use no more water in 2060 than they are now."
Kathleen Ferris, executive director of the nonprofit Arizona Municipal Water Users Association, attended the conference to advocate for Arizona towns such as the municipalities surrounding Phoenix. Municipal water use accounts for 50 percent of water use across the state, and Ferris said that providing clean and safe water requires years of preparation.
Conservation techniques have become more widely adopted over the past 30 years, she said, noting that the city of Phoenix's per-capita-per-day water use declined 32 percent between 1980 and 2010.
"We have done a remarkable job at reducing water use," Ferris said, speaking of residents in the 10 municipalities that her association serves. "We're using far less water than we used to use for the kind of population that we're serving. And the same is true in Tucson."
Tom Davis, who was representing the state's agricultural community at the conference, said farmers are among the most cognizant of the state's water supplies. Keeping the Colorado River flowing through Yuma, he said, is important to the region's agricultural stability.
"The thing about Yuma is that we have senior rights; we're the first diverters of the Arizona Colorado River water," he said. "In fact, our right is that we can divert whatever we need, consumptive use-wise, to produce our crop. So our farmers are able to farm year-round and they're able to farm a variety of crops."
Weighing the options
In an interview in the weeks after the conference, Sharon Megdal, director of the UA's Water Resources Research Center, said population growth is at the heart of the supply-gap issue. While noting that population projections can fluctuate, she didn't downplay the significance of projected gap.
"A million acre-feet is a lot of water," she said. "But is that the right number, or is that symbolic of the fact that if communities in the state wish to grow and develop in the ways they're anticipating now, there's going to be a need to figure out how to meet the water needs?"
While many avenues are being explored—including conservation, reuse and augmenting the existing supply—Megdal said that efforts to conserve water have been on the state's radar for years. She pointed to the Groundwater Management Act, signed in 1980, which outlines conservation goals for groundwater users throughout the state.
But conservation is not enough, she said.
"Conservation, demand management, using less, is certainly within the legal purview of the state of Arizona," she said. "What got said at the conference ... is that conservation alone will not close the gap. Fifty years from now, whether there will be something really, really different about the way people bathe themselves or wash their clothes, I can't tell you, but I certainly believe there's more room for conservation."
Much of the current focus is on augmentation of water supplies, mostly through desalination, which comes in two forms: the separation of minerals from brackish groundwater already stored in Arizona aquifers and the removal of salt from ocean water, which would require a plant somewhere along Mexico's Gulf of California.
A desalination plant in Mexico would require a trade agreement with that country, said Mitch Basefsky, the Central Arizona Project's spokesman for Pima and Pinal counties. Theoretically, Basefsky said, CAP would pay for the operation of the plant, Mexico would use the water that it produces, and that same amount of Colorado River water that currently goes to Mexico would remain in Nevada's Lake Mead to be used in Arizona.
But desalination also comes with its own problems. Because it is an energy-intensive method, the cost of water would grow exponentially. The cost of desalinating an acre-foot of water, Basefsky said, runs from $1,000 to $1,200. The CAP, he noted, currently sells the same amount of water to Tucson for around $160.
The technology is "getting better, but it's still very expensive," Basefsky said. "There are a lot of studies that have to be done in terms of environmental issues that come with desalination, the energy issues that come with desalination, how you dispose of the waste product."
Still, desalination remains at the center of many water discussions, even at the state capital. Arizona House Speaker Andy Tobin recently sponsored a bill, later vetoed, that would have allocated $30 million to augmentation efforts.
But desalination alone isn't enough, Tobin acknowledged.
"The cost of desal is huge, but any money we can put towards giving Arizona more options when it comes to water management is a step in the right direction," Tobin said in an email. "But desal is only one part of a long-range solution. The state has to look at all options to protect, increase and conserve our water supply."
When discussing water supply augmentation in general, the focus usually returns to proper planning. Without asking the right questions first, Megdal said, moving forward will be difficult.
"Some of these solutions do require a significant amount of advanced planning; they'll require significant investments of dollars," she said. "Obviously these decision can't be made without public input, and them being acceptable to a majority of the public. There's a lot of work to be done and I think there's going to be a spectrum of time frames over which these solutions will be developed."
The road less traveled
The patio leading into Tres English's office just south of East Broadway Boulevard is home to a 4-by-16-foot aquaponics bed. A homemade contraption of mostly wood, metal and PVC pipe, the bed is used for growing tomatoes with rainwater from last December that English has kept in two 450-gallon cisterns. The pipes carry the water through one filtration system and into a small pond underneath the bed, where the waste from 18 koi fish is then carried through another filter and onto the plants as a source of hydration and fertilizer.
One cistern is already empty. English won't make it through the summer on the remaining rainwater, but he's satisfied with coming this far without using a drop from the city.
A core member of Sustainable Tucson and director of the Tucson Feeding Program, English doesn't mince his words when discussing Tucson's water policy.
"All of our water is wasted," English said. "One hundred percent of it."
During his research to find ways of creating a renewable food supply in Tucson, English analyzed data on rainwater provided by the Pima Association of Governments and the Tucson Active Management Area. His findings include how much water goes into decorative landscaping efforts, how much is collected and used to recharge the area's aquifers, and how much is lost to evaporation.
English concluded that of the roughly 235,000 acre-feet of water that Tucson receives in annual rainfall, 92,000 acre-feet are spent on landscaping, 4,000 acre-feet are collected and used to recharge area aquifers, and 139,000 acre-feet are left to evaporate.
The core of the issue, English said, is how policymakers determine how water is allocated.
"What we haven't done, ever, is set priorities for water uses," he said. "What we have is priorities for water users. So whatever agriculture uses water on, they're allowed to do that; whatever the mines want to use it for, they're allowed to do that. There's some restrictions on water quality issues, the farms are required to be more efficient, but there are no priorities for water uses."
English said that, in theory, Tucson gets enough harvestable rainfall to produce all of the area's food. But choosing to prioritize water use for things such as food production, as opposed to landscaping, is the challenge, he said.
English said that determining water needs by estimating population growth is the wrong approach because lawmakers equate a growing population with a growing economy.
"Their perspective is that we will have an ever-growing population, an ever-growing water need and therefore we need an ever-growing water supply," he said. "But what I say to everyone on the subject is that it's not up to us to decide. We don't control the factors that control how many people live here."
English also denounced the idea of desalination as a viable method of augmentation, citing the lack of funding available and the international treaty issues that would come with a plant in Mexico. He said a move toward desalination would result in the state learning "the hard way" that pinning the economy's success on population growth is a mistake.
English isn't alone in his frustration at the lack of effort to expand rainwater harvesting. Sustainable Tucson Director Bob Cook said he is also displeased with the city's approach, and that rainwater harvesting has been treated by the local media as a hobby for those interested in living sustainably.
A former chairman of the Tucson-Pima Metropolitan Energy Commission, Cook argues that lawmakers and researchers have fallen short in providing a serious comparison of rainwater harvesting with other water conservation measures.
Although the city of Tucson provides incentives of up to $2,000 for city-approved residential rainwater-harvesting systems, Cook said that adopting the method for the commercial and industrial sectors hasn't been considered.
"We need an apples-to-apples comparison of all alternatives so we can make a rational choice," he said.
Still, rainwater harvesting has caught the eye of some local water experts. Megdal points to her center's Conserve to Enhance initiative, a program that partners with local businesses to encourage water conservation. The program currently includes local businesses such as the Epic Cafe and even national chains such as Panda Express.
Wider consideration of sustainable water practices, Cook said, likely won't come until there are hard numbers available for the cost of desalination and other methods.
"I think, first, people are going to have to see what the price tag for these other things is going to be," he said. "When the numbers come in, we really need to scrutinize those numbers. What are they including? What are they not including for both desalinization and the others?"
Though views on how Southern Arizona should approach a potential water shortage differ, most experts agree that something needs to be done. For some, that means more water sources; for others it means fewer swimming pools.
As far as English is concerned, conservation is only effective when combined with good policies.
With current conservation efforts, "You're talking about shifting who uses water," he said. "It's not like if we conserve more, we're going to use less. What's going to happen at that point is the people who conserve more will give it up to other users, and we'll end up using the same amount."
For scientists such as Flessa of the UA's School of Earth and Environmental Sciences, a multifaceted approach seems the most logical.
"When you really get down to it, I think everybody realizes that there's not one single solution to this problem," Flessa said. "It's going to have to be a combination of solutions. No one thing is going to do the trick. There's going to have to be some increase in water conservation; there's going to have to be some increase of water recycling. Desalinization may be part of the picture, (along with) greater water efficiencies on farms as well as in homes."
Megdal said that a proactive attitude toward eliminating the water-supply gap is popular among researchers. The struggle lately, she said, is that many everyday users aren't making an effort to learn more about the problem.
What's needed most at this point, Megdal said, is public involvement.
"I'd like people to get excited rather than alarmed, because I don't think people should have a sense of impending doom," she said. "What is really needed is for the general citizen, the public, to become engaged, to become interested in these water issues ... because decisions will have to be made."