A NASA scientist who flashed images of shrinking groundwater around the world Tuesday night added a local message: Water scarcity is coming to the Southeast, too.
The satellite-based technology that hydrologist Jay Famiglietti uses shows stored water steadily dwindling in the region since 2002. A global map of freshwater availability paints the Southeast a cautionary yellow, reflecting the region’s two epic droughts this century.
“It’s not clear to me that it is a reversible trend,” Famiglietti told a sold-out forum at Booth Playhouse. “It depends on management, on governance, on how we use the water.”
He spoke at “America’s Water: An Uncertain Future,” part of The Charlotte Observer and Bank of America speaker series “Our Times Re-Imagined.” The event followed a four-part Observer series in November on North Carolina water supplies.
Moderator Ira Flatow is public radio’s veteran science correspondent and host of “Science Friday.” Famiglietti is a professor at the University of California, Irvine, and senior water scientist at the NASA Jet Propulsion Laboratory in Pasadena, Calif. Three local speakers joined them.
Famiglietti’s research team uses a pair of orbiting satellites to detect dwindling groundwater supplies on Earth. The team has found that aquifers are being drained in the driest parts of the globe, including India, the Middle East and North America’s High Plains.
Images derived from satellite data show California’s water supplies changing like a traffic light: green in 2002, yellow in 2008 and an angry red, depicting a severe shortage, in 2014. The state is in the grip of a historic four-year drought.
While the satellite observations detect changing trends, they don’t reveal key information: how much water is underground.
“In many places, we don’t know how much water we have,” Famiglietti said. “That’s true in California and in many major aquifers,” the layers of soil and rock that hold groundwater.
Climate change models predict the Southern half of the U.S. will grow ever drier in coming decades. Rainfall in the Catawba River Basin, including Charlotte, has dropped 10 percent in the past half-century.
Rising temperatures, meanwhile, will increase the evaporation of water from the Catawba reservoirs. Evaporated water already equals the amount of water used by cities and Duke Energy’s power plants.
“Future generations will think we’re crazy for watering our lawns with potable drinking water,” said speaker Bill Holman, a former state environment secretary and co-writer of a landmark 2008 study of water issues.
Holman called a recent study of water supplies in the Catawba basin, looking 50 years into the future, a model for other parts of the state.
The analysis, commissioned by Duke Energy and 18 water utilities, recommended strategies that experts say could make the Catawba a reliable water supply until about 2100.
“We have our finger on the pulse of the river basin” because of that collaboration, said speaker Jeff Lineberger, Duke’s water strategy director.
Duke won a 40-year license renewal last week to continue its management of the Catawba. Duke’s power plants pull 3.9 billion gallons of water a day from the Catawba, returning most of it to the river, but its 11 reservoirs give the Charlotte region a rich water supply.
“This reservoir system was absolutely a gift from our grandparents’ generation as a shock absorber” against drought and growing demand for water, Lineberger said.
But the Catawba’s water, and the energy generated on it, is needlessly stretched thin because much of it is transferred into the Yadkin River Basin east of Charlotte, said Catawba Riverkeeper Sam Perkins. He called for changes in laws that allow water to be piped from one river basin to another.
Rapid development in the region, replacing trees with asphalt, sends torrents of stormwater and silt down local creeks, Perkins said. “The land use changes in this region (have) made it much more hard to deal with our water problems,” he said.
North Carolina is one of two states in the Southeast that don’t require permits for large water withdrawals. Its reliance on an old water-rights law means some property owners can use so much water that neighbors go dry.
That’s left some cities hesitant to invest money in new infrastructure if their legal right to water can be challenged in court, Holman said.
Speakers’ solutions to a drier world: Use irrigation water on farms more efficiently. Use stormwater instead of letting it drain away. Reform antiquated state water policies. Develop more renewable energy sources, such as solar and wind, that don’t use water.
“We’re going to have a complicated future,” Famiglietti said.