Published: October 01, 2009 01:11 pm      

Allatoona Dam and Carters Dam reduced flood damages

Mobile, Ala. –, The U.S. Army Corps of Engineers, Mobile District implemented flood control operations at Allatoona Dam and Carters Dam, on Sept. 19, due to significant rainfall and flooding in the Alabama-Coosa-Tallapoosa River (ACT) Basin. Allatoona Dam and Carters Dam operated for one of their primary missions -- flood control. Based on provisional data, a preliminary analysis indicates estimated damages prevented by having the dams would have exceeded $33 million.

“Inflows into Lake Allatoona on September 21, set the all-time record high. Natural river stages downstream of Allatoona would have exceeded recorded levels without the dam. Below Allatoona Dam on the Etowah River, our initial estimates are that flood stages were reduced 15 1/4-feet at Kingston, Ga., located 26 1/2-miles downstream of Allatoona at the US 411 bridge, ” said Lisa Coghlan, Deputy Public Affairs Officer. “Further downstream on the Etowah at the City of Rome, our initial estimates are that stages were reduced 27 1/2-feet as measured at the Ga. Loop 1 (Rome By-pass), located 41-miles downstream of Allatoona, and approximately 6 1/2 miles upstream of the confluence of the Etowah and Oostanaula and the formation of the Coosa River. Given these estimates, it is clear the Rome levee would have overtopped without the flood storage capability of Allatoona Lake,” said Coghlan.

“And finally, 6 1/2 miles below the City of Rome at the Mayos Bar Lock, stages were reduced 14 1⁄2-feet on the Coosa River, located 54 miles downstream of Allatoona Dam,” said Coghlan.

The reason for the nearly 30-feet stage reduction at Rome is due to the highly constricted floodplain in the City of Rome,” said Coghlan. The estimated natural stage at Rome that would have occurred without the dam would have overtopped the Rome levee thus causing significantly more damage than the estimated damages prevented.

“It is important to note, that no dam provides full protection from flooding: even the best flood structure cannot completely eliminate the risk of flooding. Flood risk management is a shared responsibility and partnership among, federal, state, local agencies and landowners,” said Coghlan. Through a coordinated effort among numerous Mobile Corps District offices and Alabama Power Company, the flood waters are still being managed throughout the Alabama-Coosa-Tallapoosa River Basin. The waters are being released and controlled through the remaining Corps and Alabama power projects downstream of Allatoona Dam and Carters Dam. Lake Allatoona’s current elevation is near 852.18-feet and is expected to return to approximately elevation 840 by mid-October. Carters Lake is near elevation 1081.60-feet and is forecast to be near elevation 1070.4 by mid-October.