Today, however, more and more circles are appearing across Georgia’s rural landscape, as farmers invest in high-tech center-pivot irrigation systems.
“It’s almost a necessity now,” said Sapp, Burke County’s University of Georgia extension coordinator. “I don’t know of many farmers who can put up the money to plant without some percentage of irrigated land.”
The trend toward automated irrigators that can cost $100,000 to $150,000 or more to build and install is much more than a shift in agricultural geometry.
“When you talk about economic development, water use and agriculture, people don’t always lump it all together,” he said, noting that Burke County alone produces more than $100 million in agricultural commodities each year.
Although recurring droughts certainly influence the move toward irrigators, changes in the economic climate wield considerable influence as well.
“Even if you leave out the drought part of it, in any year, two weeks without rainfall can cause you to lose a crop,” he said. “Lenders lend money against land and equipment to help farmers plant, and they almost will not lend unless you have a certain percentage that is irrigated.”
Surface streams and irrigation ponds are still widely used, but modern center-pivot irrigators typically rely on subterranean aquifers that are far less vulnerable to the effects of drought.
“Because of the complexity of agriculture these days, your business plan can’t rely on irrigating from a farm pond,” he said. “Evaporation alone can drop a pond level to nothing – this year, we see it everywhere.”
Georgia’s Environmental Protection Division, which tracks the number of water withdrawals for agriculture, has issued more and more permits in recent years.
“We have only issued seven agricultural water withdrawal permits so far this calendar year, but several hundred applications are under review,” said agency spokesman Kevin Chambers.
The number of permits, including both groundwater and some surface water systems, rose from 245 in 2008 to 272 in 2009. The number fell slightly in 2010, to 240, before increasing to 379 permits last year.
State geologist Jim Kennedy said much of the state sits above major aquifers that are both abundant and resistant to change, making them reliable resources to keep corn, peanuts, cotton, soybeans and other crops alive.
“Those are the deeper, confined systems,” he said. “The time periods for recharge are on the order of sometimes hundreds, or even thousands, of years.”
Despite more and more water being pulled from deep wells, state officials do not foresee rapid depletion of major aquifers.
“Ponds and streams are hydraulically connected with the surficial aquifers, which are affected by drought,” he said. “You can see the fluctuations, and then when we get a rainy season, the streams and ponds come back.”
Wells drilled into the deeper aquifers can, however, create temporary “cones of depression” if located too close to a similar well. Such cones could temporarily affect nearby wells, which is one reason why state regulators evaluate and issue permits for agricultural water withdrawals.
The amount of irrigated farmland in Georgia is expected to continue to grow, even if the current drought cycle subsides, according to a University of Georgia projection, which calculated that there were 1,336,291 irrigated acres in the state in 2010. That figure, the report said, is expected to expand by more than 350,000 acres by 2050.
Other studies, including one conducted during preparation of the 2011 Georgia State Water Plan, also found that the Savannah River Basin holds abundant supplies of groundwater.
“In preparing a lot of these regional water plans, we find the sustainable yield for these aquifers was higher than the level of use,” Kennedy said.