The Nature Conservancy Press Release (reprinted with permission)

Nearly 1/3 of U.S. Communities at “Extreme” or “High” Risk of Water Supply Falling Short of Demand

ARLINGTON, VA – July 20, 2010 –  Climate change will increase the risk of over-allocating future water supply across the United States, according to a report released today by the Natural Resources Defense Council.

The report, based on research from scientists at Tetra Tech, Santa Clara University, and The Nature Conservancy , is a county-by-county analysis of water supply sustainability risk based on five criteria: 1) use of renewable water; 2) sustainable groundwater use; 3) susceptibility to drought; 4) growth in water demand; and 5) future increased need for water storage.
Based on this assessment, nearly 1/3 of all U.S. counties will be at extreme or high risk of water supply sustainability by 2050— triple the number that would be at risk without climate change impacts. More than 70% of all counties will have at least moderate risk to water sustainability.

“This report sends a strong and clear message that we need a national policy now to halt climate change,” said Eric Haxthausen , Director of US Climate Policy for The Nature Conservancy. “Meaningful reductions in greenhouse gas emissions will require a suite of integrated solutions that call on every sector of society. A strong U.S. policy can catalyze global efforts to solve the pressing challenge posed by climate change.”

Several places on the future water sustainability map emerge as being particularly at risk. One of the most striking is the Ogallala Aquifer from Nebraska to Texas, one of the largest in the world. About 30% of water used for farmland irrigation in the U.S. comes from the Ogallala Aquifer.

However, the aquifer replenishes at a very slow rate compared to the rate of water extraction. Water levels have dropped by more than 100ft in many places; some estimates show it could dry up in as few as 25 years.

The good news, scientists point out, is that people can respond with on-the-ground actions that help moderate these impacts and slow the decline of this aquifer.

“One example is the U.S. Department of Agriculture’s Conservation Reserve Program, which pays farmers to restore agriculture land to natural habitat. This in turn reduces water use and increases water infiltration into the aquifer,” said Evan Girvetz, Senior Scientist at The Nature Conservancy. “This and other kinds of nature-based adaptation projects can help protect our natural resources, while protecting people against disruptive impacts to our water supply.”

Florida is  already experiencing extreme water sustainability risk. Here, wetlands restoration is preserving the landscape’s ability to store water naturally.

Through restoration and strategic land protection, the USDA’s Natural Resources Conservation Service (NRCS), The Nature Conservancy and private landowners are re-establishing natural hydrology and providing tens of thousands of acre-feet of “dispersed water storage” on more than 30,000 acres of ranchlands.

“Through the restoration of large and small wetlands throughout Florida, water will move more slowly through the region,” said Girvetz. “This provides greater flexibility of use for both nature and people.”

See original article at http://www.nature.org/pressroom/press/press4602.html