The first hydroelectric station opened on the Fox River at Appleton, Wisconsin, in 1882, and reinforced-concrete gravity and arch dams later allowed water to be stored and dropped through turbines at vast scale. Hoover Dam on the Colorado, completed in 1936, generated power while creating Lake Mead and securing water for the south-western United States. Such projects underpinned regional development schemes like the Tennessee Valley Authority and powered new industrial cities. Dams reshaped whole river basins, displacing settlements and creating reservoirs.
Large dams coupled flood control, irrigation and cheap electricity, enabling state-led regional development while permanently transforming river landscapes.