By April Reese
University of Georgia
Mark Bakker headed the engineering faculty team in the UGA College of Agricultural and Environmental Sciences. He said it doesn't take much salt to make well water unfit to drink.
"If a small amount of salt water gets into the well, you'll have to shut the well down and drill a new well or find another source for your drinking water," Bakker said.
"That's obviously an expensive trick to pull," he said, "especially when you're on an island, where you may not have any other options for drinking water."
EPA standards
The Environmental Protection Agency's standard for drinking water allows for 250 milligrams of chlorides per liter of water. Bakker believes computer modeling is one way to find the sustainable pumping rate of municipal drinking-water wells.Bakker's faculty team developed SeaWater Intrusion, a software package that works with the U.S. Geological Survey groundwater model MODFLOW, which many people are already using. SWI allows a MODFLOW groundwater model to be used as a starting point.
The UGA program may be used to find out how quickly salt water is moving inland. "It can help managers decide if saltwater intrusion is a problem in their area," he said.
Computer tools for modeling saltwater intrusion are already out there. But they're complicated, Bakker said. And they may require a supercomputer, which limits their usefulness for water management purposes.
Simplified method
"We've developed a simplified method that seems to work very well," Bakker said. "Because the existing MODFLOW program is already in use along the Georgia coast, the SWI package can be applied right away. The answers our package gives will be more than enough to base many management decisions on."The program is already being applied in the Northeastern United States and in the Netherlands near Amsterdam. Bakker hopes to see it in use along Georgia's coast soon.
Many wells in Georgia coastal communities are increasingly threatened by seawater intrusion.
The SWI package, funded by the Georgia Coastal Incentives Grants Program, is free. It can be downloaded from www.engr.uga.edu/~mbakker/swi.html on any computer with a Windows operating system. It comes with a detailed manual.
"We're gaining experience in how to apply the tool and how to be most effective with it," Bakker said. "But we want to start applying it to the Georgia coast. And we really depend on some community support or some program funding to get this going."
(April Reese is a student writer with the University of Georgia College of Agricultural and Environmental Sciences.)
