Hoover Dam(n)

TLDR: They spent decades gathering public support, 10 years in political lobbying, and just 2 years to build the largest dam in the world in the middle of the Great Depression, completing it two years ahead of schedule.

Southwest USA is a desert, with the mighty Colorado River flowing through, carving down the Grand Canyon. They identified that California is fertile, but just needs water. So they started building canals in the latter 19th century, which was a huge success. Farmers got rich, the southwest developed, and everyone was happy.

Then the river flooded & broke through one of the redirection projects and filled a low-lying basin, forming the Salton Sea. The new lake became a vacation spot, tourism boomed, hotels emerged, and a small city formed. After a few decades, salinity kept increasing (only inflow, no outflow), fish died and that area started reeking. Everyone left, and now it’s a ghost town.

After the flood, people wanted to control the river with a dam. There was also opposition, the typical American “government has no business in dam building”. After 10 years of political lobbying, they finally convinced all the states around the river and passed the bill to build the largest dam & hydroelectric plant on earth.

It was the Great Depression, and the govt decided that spending money on such a large infrastructure project would boost the economy and result in a dam as well. Six companies banded together and named themselves, well, Six Companies.

First, the “Boulder City” was built in the desert, as per the contract. Roads & railroads were laid to connect the city to the site and other major cities. Workers flocked to the city hoping for employment. High scalers climbed the steep walls, breaking any loose rocks with chisel & small doses of dynamite so that concrete will stick to them. They then blasted through the canyon walls to create 4 tunnels around the dam site, and built coffer dams to force the river into them, exposing the site of the dam. Then they dug for 130 ft (13-story building) to expose the bedrock.

Meanwhile, the two most sophisticated cement production plants in the world were built next to the dam site. After 3 years of aforementioned work, they began pouring concrete into blocks, up to 50x15x5 ft in size, cooling them with water from a newly built refrigeration plant to cure them faster. They finished the dam in 2 years and handed it over to the govt, 2 years ahead of schedule. The dam was named after the sitting president, amidst huge controversy.

The dam is no longer the largest in the world. Recent tests show the concrete is gaining strength. While it produces a lot of electricity and helps agriculture, the dam has resulted in the Colorado River Delta drying up. The river starts from the melting ice of the Rocky Mountains. Due to climate change, the river has dried up upstream as well, as evident in the color of the exposed rocks of the reservoir (called bathtub: photos). Today, the mighty river that carves the Grand Canyon does not even reach the sea.