 A number of development proposals were made for Kingman Lake throughout the 1960s.The National Capital Parks Commission banned boating on the lake in October 1961.The Commission also proposed filling in of Kingman Lake (about 50 to 60 percent of the lake's total area) and relocating some of the riprap walls, making Islands 3 and 4 part of the mainland and adding to Langston Golf Course (located on the northern half of Kingman Island).