 Despite the Interior Department 's rejection of the overall Rampart Dam project , the U.S. Army Corps of Engineers continued its engineering feasibility study on the project . That plan was completed on June 25 , 1971 , and it included most of the previous federal documents pertaining to the project , including the electricity market studies published by the Department of the Interior in 1965 , the Fish and Wildlife study of 1964 , and other studies about the economic feasibility of the project . A detailed description of potential construction methods and the overall plan for the project were included , as were reports about the site 's geography and hydrology . In total , the report encompassed two volumes including more than 480 pages . Because the construction season at the site is only five months , the Corps of Engineers projected that several decades would be needed to build the dam and associated structures . 
