A first-time visitor to Lake Lanier might think we’re blessed with an abundance of fresh water. The bridges on Dawsonville Highway and Thompson Bridge Road, or even the more modest expanse of water at Clarks Bridge Landing all present views of big stretches of lake surface. But like every single lake and pond in North Georgia, Lanier is an artificial body of water. No glaciers passed through the U.S. Southeast during the last four ice ages. So we lack the dimpled, carved-up landscapes seen in Maine or Wisconsin, where any road trip will take you past lake after lake.
Buford Dam retains Lanier’s 73 square miles of surface water. But this doesn’t mean there’s a lot of recharge going into the basin at any time. The main contributors to Lake Lanier are the Chattahoochee and the Chestatee rivers.
A trip to Helen shows quickly how small the Chattahoochee really is compared to the size of the lake it feeds. The bridge at North Main Street reveals a shallow stream just a couple of dozen feet wide. It’s similar for the Chestatee, where state route 60 follows it down from Dahlonega.
Overall, the total catchment area, or size of the drainage basin, is a mere 1,040 square miles. This isn’t much, given the size of the lake it must maintain. In addition, the Chattahoochee Basin is constrained by tall ridges on both the western and eastern side. Ideal “textbook” drainage basins are shaped like tree leaves, with a wide middle. But our local watershed has the shape of a baseball bat. In the west, the ridges of the Chattahoochee National Forest separate it from the Etowah basin.
Thirty miles to the east, near Baldwin and Cornelia, Banks Ridge splits the waters as well, forming the Eastern Continental Divide. My own front yard drains into the Chattahoochee.
But rain falling on the other side of the house runs into the Oconee, and eventually the Atlantic Ocean.
Even though the “baseball bat” is wider near Helen, the small size of the streams makes the water flowing into Lanier a scarce, precious resource. As in the past, it’s time again to think conservation and watershed protection.
Rudi Kiefer, Ph.D., is a professor at Brenau University, teaching physical and health sciences on Brenau’s Georgia campuses and in China. His column appears Sundays and at gainesvilletimes.com.