Research Stories

by Diane Boudreau

I care about sustainability—I really do. And living in the Sonoran Desert, I know that conserving water is important to ensure that there is enough for future generations. I try to make good choices, like turning off the faucet while I brush my teeth. And I bought a washing machine that uses 70 percent less water than the one it replaced. But I haven’t installed that rainwater catchment system yet, or the sprinkler system that monitors the weather and shuts off when it rains. I haven’t even done the simple task of installing low-flow showerheads—but it’s on the “to do” list.

When it comes to conserving water, frankly, I’m confused and conflicted. I want to do the right thing, but my budget doesn’t always accommodate it. Sometimes I simply don’t know what the best decision is. For instance, xeriscaping uses less water. But we’ve also learned that it can contribute to raising urban temperatures.

Finally, I’ll confess, sometimes I don’t want to give up some of the benefits of my lifestyle, like a hot bath after a stressful day.

Craig Kirkwood is a professor in the W. P. Carey School of Business at Arizona State University. He says I’m right to feel confused because the water situation in central Arizona is confusing.

Kirkwood works with researchers at ASU’s Decision Center for a Desert City (DCDC). The center was devised to bring scientists together with policymakers. Together, they examine issues associated with Phoenix-area water supplies and work to improve decision making about climate and water.

Phoenix’s water future is filled with uncertainty. The list of questions is long.

• How much will global climate change affect the desert ecosystem?
• How will local weather patterns affect flow on the Salt, Verde and Colorado Rivers, which provide much of the region’s water?
• Will the urban population continue to grow or will it plateau or even decline?

Scientists can use computers to run simulations that show how these variables might affect our water supply. But they cannot predict which scenario will come to pass. For example, recent simulations show possible future water from the Salt and Verde Rivers ranging from 19 percent to 123 percent of historical flows.

“The uncertainty has increased from earlier simulations,” Kirkwood says. “The more we study, the more uncertainty there seems to be about our future water supply.”

Even so, city planners have to decide whether to implement conservation efforts, what kinds, and on what scale. They also have to consider the needs and desires of local residents.

“It’s an interesting management problem,” the ASU professor continues. “There’s a lot of uncertainty and a lot of disagreement about values. Some people think if you live in the desert you shouldn’t use a lot of water. Other people say, well, Minnesota doesn’t have any oil, but people don’t say you shouldn’t drive cars there. Those people say that if we can get a lot of water at a reasonable cost and without significant side effects, then why not?”

Kirkwood adds, “Science provides valuable information, but it can’t answer that question because the answer depends on values. Different people have different views about what ‘a lot of water,’ ‘reasonable costs,’ or ‘significant side effects’ are. It is these questions of values that are central to deciding what we should do.”

Environmental science and public policy continue to mingle with increasing frequency. It is management experts like Kirkwood who bring a business perspective to the discussion.

“It’s one of the joys of interdisciplinary research—getting different perspectives. Craig comes at our work from a structured decision analysis perspective. He has challenged us to look at water management decisions as tradeoffs between sustainability and lifestyle,” says Patricia Gober, co-director of DCDC.

At DCDC, researchers work with professionals from both state and municipal water resource departments. Together, they’ve developed WaterSim and other decision-support tools. WaterSim is a computer simulation of water supply and demand for the Phoenix metropolitan area. Users can adjust settings to explore water supply conditions in response to changing variables. Those variables might include climate change, drought, population growth, technological innovation, and policy decisions. The simulation provides researchers with a range of potential scenarios. What it cannot do is forecast which scenario will actually occur in the future.

“Waiting for better forecasts about future water supplies before we decide what to do is not that useful,” Kirkwood says. “Two decades of research have shown that there is plenty of uncertainty that is not going to be resolved before we need to make decisions. We’re better off looking for policy alternatives that are flexible in dealing with the uncertainties while not being too expensive. We need policies that would adapt to conditions as they develop over the next few decades.”

For example, if demand for water exceeds supply, policymakers have two basic options available. They can increase supply or reduce demand. Increasing the water supply might involve buying agricultural land and converting the water to urban use. Or it might involve buying water from other regions. It could also mean increased use of treated wastewater for industry or urban landscape watering.

There are methods to reduce demand as well. For example, developers could be required to build community pools instead of private pools. New homeowners might not get a choice between having desert landscaping or a lush green lawn. Pricing might be used to promote conservation. The cost of water could increase. Rebates might be offered as an incentive to purchase low-water-use appliances.

Kirkwood says that these options involve tradeoffs, such as higher cost or lifestyle changes. But the professor is helping to address the costs and benefits of various options in a systematic way.

“Our lifestyle is built on inexpensive, abundant water. Available scientific evidence shows this way may not be feasible in the future, but we cannot say this for certain,” he says. “It seems useful to investigate the options that are available while any potential crisis is still in the future, rather than having to deal with it on an emergency basis. It’s not easy to reconcile the views of different water stakeholders. However, we can help clarify the tradeoffs and available options.”

“It’s up to community leaders to make those choices,” adds Gober. “We don’t want to be seen as leading public policy—we want to be supporting public policy. The role of a university is to provide a forum for people to talk about issues like sustainability.”

Kirkwood has been studying, teaching and writing about decision making for decades. He applied his expertise to issues such as hazardous materials management, energy planning, and nuclear waste disposal before turning his attention to water.

“I’ve always been interested in the future and the role of uncertainty in dealing with the future,” he says. “How do you deal with recognizing you can’t forecast the future? There are ways to deal with the uncertainties other than to ignore them or consult the stars. Approaches developed during the past 50 years are being used to clarify public and private sector decisions. It’s an exciting time as we deal with very important decisions that impact the world in which we and our descendents will live.”

Research at the DCDC is funded by the National Science Foundation’s Decision Making under Uncertainty initiative. For more information, visit DCDC on the Web at http://dcdc.asu.edu