Water scarcity in the Western U.S. has long been an issue of concern. Now, a team of researchers studying freshwater sustainability in the U.S. have found that the Southeast, with the exception of Florida, does not have enough water capacity to meet its own needs.

Twenty-five years ago, environmentalist Marc Reisner published Cadillac Desert: The American West and Its Disappearing Water, which predicted that water resources in the West would be unable to support the growing demand of cities, agriculture and industry. A paper co-authored by a University of Georgia researcher and just published in a special issue of the journal Proceedings of the National Academy of Sciences offers new support for most of Reisner’s conclusions, using data and methods unavailable to him in 1986.

Although the paper focuses on freshwater sustainability in the Southwest, co-authors Tushar Sinha, a postdoctoral scientist at North Carolina State University; John Kominoski, a postdoctoral associate at the UGA Odum School of Ecology; and William Graf, a professor of geography at the University of South Carolina, said that the findings have important implications for the Southeast as well. “It turns out that the Southeast has a relatively low capacity for water storage,” said Graf.

Regional water needs

In order for water supply to be considered sustainable, the researchers calculated that no more than 40 percent of freshwater resources can be appropriated for human use, to ensure that streamflow variability, navigation, recreation and ecosystem use are accommodated. They also determined how much water a region would need to meet all its municipal, agricultural and industrial needs—its virtual water footprint. The VWF includes the water needed if a region were to grow enough food to support its own population.

The researchers found that neither the Southwest nor the Southeast have enough water capacity to meet all their own needs; both these regions virtually import water from other parts of the country, in the form of food. “The Southeast has virtually no positive, inland VWFs,” said Kominoski, who earned his doctoral degree from the Odum School. “The largest population centers in southeastern states, with the exception of Florida, are inland. Piedmont cities such as Atlanta, Charlotte and Birmingham rely on small watersheds, which may be why our VWFs are negative.”

Study lead author John Sabo, associate professor at Arizona State University, added that the Southeast’s municipal and industrial water demands are higher than supported by locally generated streamflow.