Hoover Dam

After THE canyon we spent a couple of days in Las Vegas. This is only half an hour from the Hoover dam which was definitely on my bucket list. Not only is it an engineering wonder it has some nice Art Deco touches. This is one of two angels that abut the flagpole.

While the intakes continue the theme.

Unusually the spillways, rather than being open flumes, flows into one of the tunnels that were used as part of the initial diversion works. The concrete still looks new helped by some great quality work and a dry hot climate that is quite benign compared to structures nearer the coast.

The Colorado marks the boundary between Nevada and Arizona. The whole scheme affected 5 states and took almost 100 years to gain political approval which ultimately got over the line by agreement to hydro-power sales funding the project. Other benefits were substantial including irrigation which opened up much of California as well as flood control. Tourism is also now making quite a contribution.

With two states there needs to be two power plants……They generate over 2,000 megawatts.

The pen-stocks are huge (30 ft dia) but are divided and reduced in size to increase the velocity for driving the turbines.

While the 8 turbines (these are on the Nevada side) are no less impressive producing some 100 megawatt each. Their size can be appreciated when compared to the quite large (American sized!) truck. Lifting the 600T turbines requires both rail gantries to operate in tandem.

Construction comprised building two by pass tunnels on each side, an upstream cofferdam to divert the river and a downside cofferdam to prevent the river flowing back into the site, and then constructing using mass concrete in “blocks”. The numbers are staggering. Base width 200 metres and 14 metres at the top with 2.6M m3 of concrete. One unique aspect was the use of cooling pipes within the concrete pours to assist in curing and reducing thermal cracking. For those who like drawings…

One element that helped the dam to be completed two years ahead of schedule (5 years rather than 7 years) was a series of aerial runways. One is still in place and remains not just the largest on site but one of the largest in the world. Apparently it is still used occasionally.