In 1958 the Corps again was directed by Congress to study dams, this time to improve water quality in addition to flood control. Tension between legislation for park use and water management use increased, until President Dwight D. Eisenhower proclaimed Chesapeake and Ohio Canal National Monument under the authority of the Antiquities Act on January 18, 1961. The proclamation earned the enmity of House Interior and Insular Affairs Committee Chairman Wayne Aspinall. Later in 1961 a park authorization bill was proposed with Aspinall's support that would allow dam construction on the Potomac. In May 1962 the Corps proposed a new scheme for 16 dams on the Potomac and its tributaries. This version scrapped most of the mainstem dams in favor of more tributary dams, and moved the Riverbend Dam to a site at Seneca, upstream. The Seneca Dam was to be lower than Riverbend. Douglas immediately attacked the proposal, as did Maryland Representative Charles Mathias. A task force review in 1966 opposed the Seneca Dam. In 1968 draft legislation proposed the Potomac National River, eliminating the possibility of a Seneca Dam in favor of more tributary dams. However, this proposal was opposed by landowners and other interests in the areas earmarked for dams on the Monocacy, Cacapon and upper Potomac rivers. In 1968 Congress converted the national monument into Chesapeake and Ohio Canal National Historical Park, effectively precluding dam construction anywhere along the length of the park. By 1969 the Seneca Dam proposal had been publicly abandoned by the Corps of Engineers.
