Boaters are eating away at Georgia's coastal marshes.
A new study rules out lack of dredging as a reason the state's Intracoastal Waterway is eroding.
Researchers at the Skidaway Institute of Oceanography compared historic charts and photos with modern evidence to try to determine what's causing banks along the snake-shaped coastal boating route to fall away.
The Institute's Clark Alexander suspected shallowness caused by years of deferred maintenance or even rising sea levels.
But he concluded it was simply the waterway's intended purpose, to provide commercial and recreational boaters with an easy passage.
"I'm not sure that there's anything that we can do other than to moderate how close we come to the channels," Alexander says. "It's a dilemma."
Erosion can harm the state's shrimp and oyster populations by destroying their habitat, but restricting boating on the Intracoastal Waterway would defeat its purpose.
"In areas where we have higher population growth, we have both banks of the waterway eroding, indicating that that is not a natural process that is occurring," Alexander says. "It's signifact."
The Institute's research shows that some marshes are eroding at the rate of about 30 feet per year.
On average, however, Alexander says, the rate is about 1.5 to two feet per year.