A final design for a new spillway at Folsom Dam to improve flood protection has been approved.

The U.S. Bureau of Reclamation and U.S. Army Corps of Engineers signed off on the $1.3 billion project Thursday. The design features a spillway with six gates to be constructed next to the main dam. The gates would be used to release more water downstream into the American River in the event of a flood. The spillway will also serve as an overflow facility for the dam to prevent its failure in the event of copious runoff.

Completion of the spillway is scheduled for 2015. The bidding for building the spillway is expected to begin in the next few months, with the contract awarded by September, according to the Bureau.