AN INVESTIGATION OF DAM RELEASE DISCHARGE AND SEDIMENT LOSS ON THE ETOWAH RIVER, ROME, GA, USA

The headwaters of the Etowah River begin in Lumpkin County, GA and flow 160 km in a south to southeast direction to become the primary surface water inflow for the Lake Allatoona reservoir. From the Lake Allatoona dam (34°8′18″N, 84°38′38″W), the Etowah River flows about 48 km downstream towards Rome, GA (34° 15' 25'' N, 85° 9' 53'' W). The dam began retaining and releasing water on January 31, 1950 for purposes of generating hydroelectricity and flood protection. With the construction of the Allatoona dam, the flow rates and patterns of the Etowah River transitioned from a river with a more natural flow pattern to one with flow patterns controlled by dam releases whereby the daily stage change averages five feet causing an increase in discharge averaging from 1000 cubic feet per second to 6000 cubic feet per second in Rome, GA. Through the installation of bank erosion pins (Station 1, 34°14'43" N, 85°10'06" W; Station 2, 34°14'52" N, 85°10'34" W), we quantify the amount of sediment lost during dam release. At Station 1, we found 25 mm of sediment lost over one and a half months with maximum discharge at 4000 m3/s. At Station 2, there was varying sediment loss along the bank with measurements ranging from 6.35 mm to 19.05 mm.