Water Conservation: Arizonans Search for Lasting Solutions

The dire predictions grow worse each year: Arizona and the six other states that draw their drinking water from the Colorado River are facing an increasing demand and a dwindling supply.

In the Tucson area, a 15-year drought forced the city to use less and conserve more.

Mayor Jonathan Rothschild said Tucson is using less water than it did 20 years ago, even as its population has grown by 200,000 since then. It has focused on conservation efforts, such as persuading people to switch to more-efficient toilets, making landscaping choices that use less water and encouraging rainwater harvesting.

But house-to-house conservation is “a losing strategy,” according to environmental officials and consultants, who say lasting solutions will come only from ambitious and far-ranging applications. Throughout Tucson, researchers and scientists are investigating some of these, as well as the impact they may have on the way residents live and eat and the environmental choices they make.

Among the more promising approaches are reclaimed wastewater, products to fight off the high evaporation rates in Arizona and research on propagating plants that use water more efficiently.

Each summer for the last five years, Shane Snyder, a professor of chemical and environmental engineering at the University of Arizona, has made the 20-hour trek to Singapore, a world leader in recycling wastewater.

Mr. Snyder, who is also a director of the new Water and Energy Sustainable Technology Center, has a particular interest in the innovations that Singapore has achieved with NEWater, the country’s recycled wastewater that is bottled and safe to drink.

“Water reuse is so important,” Mr. Snyder said. “We need to get as much mileage from the water we get as possible.” He said this was important because water is scarce and it takes a lot of energy to transport it to users.

Technology available today is capable of taking water from any imaginable source and, with enough treatment, making it pure again, Mr. Snyder added.

One of the biggest challenges is public perception.

We need to try and get people to not think about the water’s history and where it comes from, but think of the water’s quality.

—Shane Snyder

Though Singapore copied American water technologies, it was more open about its procedures, which helped the effort to gain public acceptance and turned NEWater’s facilities into a tourist attraction: There are public tours, which explain the water recycling process.

Beyond convincing the public to move past the stigma of drinking reclaimed water, another challenge is the life cycle of the purification equipment. Mr. Snyder said that after a year or two, problems can develop because membranes involved in the filtration system have a short lifespan.

In Tucson, each lake and other large body of water is estimated to lose 100 inches of water annually to evaporation. From an uncovered swimming pool, that could mean up to six feet of water lost every year.

An associate professor at the University of Arizona, Moe Momayez, has been developing a product called Hexocover since 2008 to help fight the evaporation. Hexocover is a hexagonal-shaped floating cover made from recyclable plastic. It is
used to reduce evaporation in mining plants so that more water is left to be pumped back through the plant, which cuts down on the water drawn from the Colorado River or aquifers.

Through testing, the Hexocover company discovered that covering a majority of the surface of a body of water can reduce evaporation up to 85 percent.

The covers are also designed to double as solar panels, generating energy. The interlocking design enables users to take out individual panels for maintenance. Mr. Momayez said the panels can be left in bodies of water for long periods of time. The two-layer design allows for the panels to stay afloat more easily, with wind passing through the gap between the layers, which pushes the panels down instead of blowing them away.

The company’s main clients so far have been large corporations as well as municipalities, some overseas in South Africa, China and Chile.

“We hope to market the product for any kind of open body of water ─ lakes, storage facilities and pools,” Mr. Momayez said. The element of solar energy and the convenience of controlling the panels through a cellphone app make it more attractive than the typical swimming pool tarp, he added.

Agriculture is the biggest user of water in Arizona by far, consuming about 60 percent. Alfalfa is a particularly thirsty water guzzler. David Galbraith, a professor in plant sciences at the University of Arizona, said there are some places where alfalfa “is growing to the extent that you can feel the humidity in the air across the growing area.” Pecans, a large crop in southern Arizona, are very inefficient water users, requiring large amounts for optimal growth and fruit production.

It seems somewhat ironic that even if cities are using basically no water at all, we still have a water problem because of agriculture.

—David Galbraith

One way to address the problem is to try to isolate the plant genes involved in responding to drought and salt conditions. An understanding of the genes and how they work together, Mr. Galbraith said, would possibly allow the engineering of more drought-tolerant plants. But creating more-efficient plants is much harder than many initially anticipated.

But these approaches will take time, Mr. Galbraith said, because genetically engineered crops take many breeding generations to develop.

“The bottom line in all of this is that life is turning out to be more complicated than we ever dreamed,” Mr. Galbraith said. “The idea of being able to go in and just do one or two things in a plant and get drought tolerance or salt tolerance is not likely to be successful.”