Powering the Southwest: The Story of Hoover Dam

Long ago, the mighty Colorado River flowed wildly through the American Southwest. During the spring, melting snow caused the river to overflow its banks, flooding nearby farmland. In the hot summer, the river dried up, leaving farmers without enough water for their crops. To solve these problems, engineers in the 1930s planned an ambitious project: building a gigantic concrete dam in Black Canyon, right on the border between Nevada and Arizona.

Building the Hoover Dam during the Great Depression was a monumental challenge. Before workers could build the dam, they had to move the river out of their way. Miners drilled four huge diversion tunnels through the solid canyon walls to redirect the water around the construction site. Next, brave workers known as "high scalers" hung from ropes hundreds of feet above the ground to clear away loose rocks. Once the area was safe and dry, thousands of laborers worked day and night pouring millions of tons of concrete into massive interlocking blocks. They even installed special cooling pipes inside the concrete so it would cool quickly without cracking.