By April Reese
University of Georgia
Computer software developed by University of Georgia scientists
can enable coastal cities to determine safe pumping rates to keep
salt water out of municipal wells.
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
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.)
