OMAHA, Neb. (AP) — The Army Corps of Engineers is preparing to decrease the flow from Gavins Point Dam in South Dakota to increase flood control storage on the Missouri River, which had record flooding this year.The corps plans to gradually decrease the release starting Thursday. Officials say the current release rate of 40,000 cubic feet per second will be decreased by 3,000 cfs each day until Dec. 14, when the flows will be set at 20,000 cfs for the winter.The corps had initially planned to decrease the flow last week, but extended the high release to add additional storage for the runoff season next spring. The Missouri River had a summer of flooding because of heavy rain and melting snow.