June 1, 2012
Glen Canyon Dam
The Glen Canyon Dam was under construction from 1956 to 1966, while actual pouring of concrete took place from 1960 to 1963. Its reservoir, Lake Powell, completed filling in 1980. Record high levels in 1983 led to a dangerous situation when the spillways were opened. After a few days the dam began to shake violently as heavy cavitation was destroying the concrete and washing away the rock below. The spillways were closed and the quick application of that miraculous material called plywood allowed them to stave off disaster (I suspect some duct tape may have been involved as well). The spillways were redesigned and repaired and the problem did not re-occur in 1984 when high water levels again required them to open the spillways. A later study has indicated that the catastrophic failure of the Glen Canyon Dam would lead to the scouring of the Grand Canyon and overtopping of Hoover Dam.
Glen Canyon Dam on the Colorado River. The Glen Canyon Bridge is in front of it. Behind it is Lake Powell.
The greensward down there really is a grass lawn. Three football fields in area, the dam does not sponsor a soccer team!
The turbine room. There are 8 turbines and they are replacing number 5, as part of routine maintenance. The original turbines were made of cast iron in Belgium. The new ones are stainless steel and made in Canada.
Originally, the bridge was built solely to build the dam. It was not intended to be used as a public highway, but later the Arizona DOT certified it as acceptable for highway use. The speed limit on the bridge is 25 MPH. There are parking places at each end of the bridge and sidewalks along both sides of the bridge. Arrow slits are cut in the fence to allow photographers to get clear shots of the marauding Saxons. There are also breaks in the barriers that separate people from traffic, allowing pedestrians to jaywalk across the highway. A more casual approach to security and safety than I expected.
Such an amazing structure. It's one of those things that you have to see in person to really appreciate.
Posted by: Concrete Screed at Jul 6, 2012 9:46:52 AM