Opposition to the dam began in the 1960s from both local and nearby St. Louis area residents. Local farmland was taken by market price condemnation. Recreationists from the city believed it would have severe impacts on environmental, economic, and engineering concerns, and the value of the Meramec as a free-flowing canoe navigable stream. Construction industry officials, local politicians, and developers saw the prospect of great economic prosperity with a major lake only one hour from St. Louis. Dill was first pro-dam, thinking he would run glass-bottomed boats in the cave, but he joined the opposition when a survey of the cave showed that the dam near Sullivan would back upstream into the cave, and flood 80% of the cave when the lake was at normal pool.