Hoover Dam. Amazing proof of human wit.

One of the America’s favorite cities would not exist as we know it today without Hoover Dam. California and other Southwestern States neither. Prices of vegetables in US would be higher.  Hoover Dam is the heart of Southwest, providing clean energy, water, protection against floods and recreation to millions of people. 

Las Vegas Strip-Hoover Dam. 35 miles and 45 minutes ride (Google Maps).

Colorado River flows along a 1,400 miles course from the Rocky Mountains to the Gulf of California (Mexico). It had flowed free for 40 million years, until the human being dominated it in 1935.

First settlers suffered the seasonal changes of the River. It was a love-hate relation from the very beginning. Agricultures need the water that Colorado River provides, and settled in its low farmlands. It was like an Oasis in the desert. But in late spring and early summer, the snow of the Rocky Mountains melted causing massive floods and destruction. During late summer and fall, the river dried to a trickle, too low to divert.

People from the East, especially North East, did not see this as a Federal issue, so no solution was provided. In addition, the share of the water involved seven States, what made the problem bigger.

In 1922 a representative of each State signed an agreement, which divided the Colorado River in two basins, upper and lower half. It paved the way for the Hoover Dam.

The upstream face of Hoover Dam. Looking downstream from the Arizona rim (Own Photo).

Construction began in 1931. It was the zenith of America’s Great Depression, when the workers were desperate for a job with they could feed their families. The first three weeks after project was announced, local job office received 12,000 applications. In the beginning, workers and their families lived in tents around the construction place and the river. 21,000 men worked in the Hoover Dam and lived with their families in poor living conditions and extreme temperatures.

It was dessert: no cities, no water supply, no roads nor any infrastructure, and the nearest railroad was in a small unknown town called Las Vegas 35 miles far away.

The live conditions were so bad, that the company had to build everything, even a new town, Boulder City. The city was well designed and constructed, as a symbol of prosperity in the Great Depression days.

The downstream face of Hoover Dam. Looking upstream from the Arizona rim (Own Photo).

Construction:

Phase 1: Four tunnels were constructed to divert Colorado River, making a dry area where the dam could be placed. Rock excavated from the tunnels was laid into two temporary coffer dams to divert river to the tunnels. Tunnels opened in November 1932.

Phase 2: 2.6 million cubic meters was poured to construct the dam.

Two huge manufacturing concrete plants were built on the construction side for providing this huge amount of concrete. But engineers had a big worry: Heat.

When we mix the ingredients of concrete: water, sand, rocks and cement, there is a chemical reaction, which generates internal heat slowing down the curing process. The larger you pour, the longer it cures. So they decided to build Hoover in a series of interlocking blocks of 5 feet height, but that was not enough. To cool the concrete more, the engineers disposed a system of pipes crossing the blocks of concrete. They pumped cold water in the pipes, so the concrete cooled down.

To make the construction even faster, they organized a competition between the different pouring teams, and it worked! 8,000 thousand cubic meters of concrete were poured each day.

In January 1935, arch was completed, and in September 1935 the very last concrete was poured, when President Franklin D. Roosevelt dedicated the Dam.  The construction of the power plant finished one year later. The Lake Mead needed 6 years to be completely filled, but the generation of electricity began before. In 1939 the Dam’s power plant became the largest hydroelectricity facility in the world. 112 workers gave their lives to make this dream possible.

Hoover Dam Power plant (Own Photo).

  

Facts:

Location: Colorado River. Between Nevada and Arizona. 35 miles from Las Vegas.

Cost: $49 million ($811 million today, 6 Gareth Bales)

The Dam:

Type: Arch gravity.

Height: 726.4 feet (221.3 meters, half of the Empire State Building height)

Crest length: 1244 feet (379.2 meters)

Crest width: 660 feet (201.2 meters)

Volume of Concrete: 3.25 million cubic yards (2.6 million cubic meters)

The Powerplant:

Commercial generating units: 17.

Nameplate capacity: 2800 megawatts (enough to serve 1.3 million people)

Energy Distribution: California: 55.91%, Nevada: 25.14%, Arizona: 18.95%

Lake Mead:

Shoreline: 550 miles (885 km, 1.44 times Delaware shoreline)

Capacity: 28,254,000 acre-feet (34.85 billion cubic meters, enough to cover all the State of New York with 30 cm of water)

Maximum depth: 498 feet (151.4 meters)

Surface area: 156,800 acres (63,455 hectares, almost 89,000 soccer pitches)

Length when full: 110 miles (177 km)

More info:

Info and Tickets: http://www.usbr.gov/lc/hooverdam/index.html

National Geographic Megastructures. Hoover Dam: http://www.youtube.com/watch?v=pBJq4W9V4Lw

Wikipedia: http://en.wikipedia.org/wiki/Hoover_Dam

Old Photos of Dam’s Construction: http://www.ecommcode.com/hoover/hooveronline/hoover_dam/before/toc.html

Hoover Dam reinvented: http://channel.nationalgeographic.com/channel/man-made/videos/a-new-hoover-dam/