On a rainy February day in 1964, President Lyndon Johnson spoke to a crowd near here and said that God had given the country great estuaries, natural locales for harbors, but had left people to dredge them for modern ships. He then triggered an explosion that broke ground on the Cross Florida Barge Canal, a grand attempt to reshape Florida for heavy industry. Grim weather that day foreshadowed the canal's troubled future, and as activists and opponents drew attention to its cost and environmental impact, support for the project plummeted. Instead of shuttling barges through Rodman Reservoir, Buckman Lock now opens to boaters, paddlers, and manatees. Working like water stairs, the lock raises and lowers water levels to move boats, and to protect migrating manatees, researchers developed a system in which canal sensors detect nearby animals and pause the massive hydraulic gates.