The U. S. Army Corps of Engineers plans to reduce operating hours at the Barkley Navigation Lock to save money. The Corps announced Monday it will go from a 24 hour to a 20 hour a day operation, starting Jan. 7, 2013. The lock will close from 2 a.m. to 6 a.m. Corps officials hope the change will free up more funding for maintenance costs. Two other locks on the Tennessee River will also operate on reduced hours.