Escalating climate change poses a paradoxical dilemma when it comes to water, according to speakers in a panel on the subject at the 2014 ULI Fall Meeting in New York City. While developers and planners face a future in which water to supply local communities will be an increasingly scarce commodity, they said, they also need to build resilience features to prepare for sudden deluges of stormwater from extreme weather events that will become increasingly frequent.

With the rise in greenhouse gas emissions unlikely to abate before 2050 to 2100 in a best-case scenario, it’s a given that water is going to be a major problem, according to John K. McIlwain, a ULI senior resident fellow, who moderated the panel.

“From a practical real estate management and city planning point of view, we need to be planning for volatile events,” he warned.

The Southwest will become progressively drier, McIlwain said, but will also be at risk for flooding. There will be “too much and too little water in the same states, at different times,” he explained.

Arizona, which gets only about eight inches (20 cm) of rain per year but still is plagued by flooding from summer monsoons, is a template for the future of southwestern states such as Texas, panelists agreed. Steven A. Betts, president of Phoenix-based Chanen Development, noted that his state has been battered by hurricanes that came up the Sea of Cortez in Mexico and stalled over Arizona.

Meanwhile, coastal urban areas such as the New York City region will be threatened by storm surges, akin to the floodwaters from Hurricane Sandy in 2012. But the panelists also pointed to an assortment of solutions for water woes that have proved to be workable—if states and local communities show the foresight and discipline to apply them.

For example, Arizona has long practiced water conservation in order to make the most of a limited supply that comes via canal from the Colorado River, from mountain snowmelt captured by dams, and from groundwater, Betts said. Measures include extensive recycling of “graywater,” some of which is put into the ground and used to recharge groundwater.

“The ground filters it,” Betts said. “It can be used for drinking water. In other parts of the country, they freak out about that concept.”

Such measures, coupled with a decrease in the agricultural use that accounts for about 70 percent of Arizona’s demand, have enabled the state to ensure that it will have enough water to sustain continued growth in the three-county region that includes Phoenix and Tucson, according to Betts.

Texas, in contrast, is just starting to come to grips with its escalating water problem, according to Laura Huffman, Texas state director of the Nature Conservancy, who also leads the organization’s nationwide urban water conservation efforts. But solutions are urgently needed because of expected population growth. Houston, already the fourth-largest city in the United States with nearly 2.1 million residents, is expected to double in population over the next several decades, she said.

Texas is planning for 25 percent of its future water needs to come from conservation, according to Huffman.

Huffman said that controlling water consumption also is crucial for economic reasons, because Texas cities own their water utilities. Building new projects to bring water from distant sources would result in costly price hikes for consumers. The dilemma, she explained, is “how we can have our cities growing and not price our people out of the markets.”

The state has pioneered the use of nonpotable brackish water from underground aquifers. At least a dozen communities in Texas have plants to desalinate brackish water as a water source, and the state’s 2012 water plan calls for increasing use. But Huffman said desalination is still so expensive that other measures should be tried first.

Significant water savings could be achieved by reducing the 30 percent of agricultural water use that is wasted. Simply lining irrigation canals to reduce losses could save enough water to supply cities for decades, Huffman said.

Successful conservation requires a combination of carrot-and-stick measures, Huffman said. Inverted rate structures, which charge large users a higher rate, are a powerful incentive for reducing lawn watering and other wasteful uses.

The panel also discussed the problem of storm surges. One participant, Gerald Romski, is project executive and general counsel for Arverne by the Sea, a Queens, New York, housing development designed to withstand a category 3 hurricane. Its features include a water retention system under each home, and the use of fill to raise the height of the ground by eight to nine feet (2.4 to 2.7 m). A beachfront preserve was erected to absorb the energy of storm surges.

After the development survived Sandy with relatively little damage, it actually began touting resilience in its marketing efforts, Romski said.