Lake Lanier's Tiny Water Basin

Sometimes a great picture can really say more than a thousand words. Why is Lake Lanier having such trouble supplying water to those people who need it? Take a look at this map and the answer becomes clear...

Explaining the Map

• Lake Lanier is part of what is called the ACF river basin. ACF stands for Apalachicola-Chattahoochee-Flint, the three major rivers that ultimately drain down into the Gulf of Mexico in Florida. Thats the green area on the map.   
  
• Lake Allatoona is part of the ACT river basin, whose initials stand for Alabama-Coosa-Tallapoosa. Thats the brown area on the map.

So where does Lake Lanier get the water to feed the huge green area? That's the tiny yellow are at the top of the map.

Original Source