The Chattahoochee River originates in the Southern Blue Ridge Mountains above Helen, Georgia, and drains almost 5.6 million acres (8770 mi2) of piedmont and coastal plain landscape in Alabama and Georgia. With a length of 430 miles, it is commonly divided into three segments, with the Upper Chattahoochee flowing through Atlanta before becoming the Middle Chattahoochee through Columbus. From Lake Walter F. George, the Lower Chattahoochee
flows south toward Lake Seminole, where it joins with the Flint River to form Lake Seminole, which drains, in turn, into the Apalachicola River and the Gulf of Mexico. Along the way, the Chattahoochee provides drinking water for more than half of all Georgians and recreation opportunities on the reservoirs above the 13 dams that punctuate its course.