Fort Loudon was the last dam built on the Tennessee River. Construction began in July 1940 and was completed in June 1944. The dam was constructed in three phases. Phase One was the lock and earthen dam on the south side of the river. The lock was constructed on Belle Island. Phase Two was the construction of the spillway. Phase Three was the construction of the Powerhouse. During the construction of the lock and earthen dam, all of the water was channeled through the main river channel. During the construction of the spillways, the water was channeled through the lock and remaining river channel. During the construction of the powerhouse, the water was diverted through the spillways and the lock.