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Winning the "Water War"

by Joey Piergrossi



Farmers throughout Georgia are sweating, and not just because of the heat. The increasingly frequent and long-lasting droughts of recent years and a dispute over usage rights with neighboring states have made water for their crops a scarce local resource.

Calvin Perry, a research engineer with the National Environmentally Sound Production Agriculture Laboratory (NESPAL) at the University of Georgia in Tifton, hopes to help farmers with a technological system that he and his team have created to save water by managing how it is delivered to their fields.

“Our goal is to help farmers make the best use out of every drop and improve their bottom line,” he said.

Perry’s system, called Variable Rate Irrigation (VRI), is a redesign of the central pivot, the long, scaffold-like, wheeled device commonly used for irrigation and seen nearly everywhere crops are grown.

With traditional irrigation, the rate of flow from each sprinkler and across the field has been about the same. This means that many of the crops are sometimes overwatered even as others may be underwatered.

VRI, on the other hand, uses pressure regulators on the sprinklers of the central pivot to manage how much water comes out at any given time. The farmer uses a personal computer to adjust the settings to reflect the distribution of the field’s crops and the optimal amount of water that each particular crop should get.

“On average, we determined that this process saves 17 percent of the water normally used,” Perry said.

VRI has another important benefit. Because the system irrigates the crop precisely according to its needs, yields will likely be higher as well.

A heightened regional interest in water conservation comes as Alabama, Florida and Georgia are embroiled in a lawsuit stemming from their mutual water shortages, said James Hook, a professor of crop and soil sciences at NESPAL and a collaborator of Perry’s. Dubbed the “water war,” the suit has Alabama and Florida accusing Georgia of using more than its fair share of water and suggesting that some of the waterways that cross into those states from Georgia be closed to the state’s residents — including its farmers.

Hook noted that the water-saving advantages of the VRI system are not only economically attractive in their own right but could also stave off the threat of such shutoffs. By seeking pragmatic solutions, Perry agreed, “we in Georgia show that we are being proactive, should the water war go to the U.S. Supreme Court.”

Perry has been working with the federal government to set up cost-sharing programs based on his technology at 30 Georgia farms, and he plans to place many more around the state by the end of this year. The states of South Carolina and Mississippi have also begun implementing their own cost-sharing programs to get the VRI system set up with their farmers, and Texas, Colorado and Nebraska, as well as Spain and Italy, have shown interest. They are attracted not only by the prospect of drought relief through water conservation, Perry pointed out, but also by the possibility of higher crop yields.

Closer to home, litigants Alabama and Florida are themselves interested in the VRI technology.

For more information, contact Calvin Perry at


Research Communications, Office of the VP for Research, UGA
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