LINCOLN, Neb. (AP) – The U.S. Army Corps of Engineers says it will reduce water releases from Gavins Point Dam in South Dakota, a sign that major Missouri River flooding could be nearing an end.     The corps’ Omaha District construction chief, Robert Michaels, says the corps will decrease the water volume gradually from its current 160,000 cubic feet per second. The corps plans to drop the flow to 155,000 cubic feet per second on July 31 and cut it to150,000 cubic feet per second on Aug. 1.  Michaels said Tuesday that the corps will trim the releases slowly to keep the water flow stable and prevent further erosion of flooded farmland and roadways.  Missouri-based flood expert David Rogers says lowering the levels gradually is crucial to lessening the risk of levee failure.