Have school will travel: But it's a dry heat!

But it's a dry heat!

Friday June 22, 2007
Hoover Dam, Arizona/Nevada

When I was a child, my burning desire was to grow up and build dams and bridges. My heroes were those engineers who built the graceful suspension bridges and soaring dams. I loved the Golden Gate, Brooklyn, Verrazano Narrows Bridges….Hoover, Shasta and Grand Coulee Dams. I poured over the biographies of engineers like John Roebling, the builder of the Niagara Gorge and Brooklyn Bridges. No small creek was safe from being dammed when I was around.

This fascination lasts until today – I will drive far out of my way to view a dam or a large bridge. As a young teen, I built a 30 foot long version of the Gold Gate Bridge out of Tinkertoys and Hot Wheels track, spanning our living room, dining room and foyer in the process. My mother displayed the patience of a saint indulging my ‘hobby’.

Somewhere along the line computers captured my attentions – I soured somewhat on dam construction when it finally dawned on me that building a large lake put a lot of nice and sometimes spectacular real estate under water. I figured this out when I traced the outlines of a proposed lake in the North Georgia mtns on a topographic map. I realized to my horror that the new lake would cover a favorite camping area. My attitude toward new lake construction changed after that observation.

However, I still love to view the big dams, and Hoover Dam is the mac daddy of them all. I saw the dam in my teens on a cross country trip with my parents. We were able to view the dam and drive across it, but I was bitterly disappointed when we were unable to tour the powerhouse and the facilities. I’ve always wanted to come back, and today was the day.

It was a cool, balmy 105 degrees (not!) when we left Las Vegas for the short drive over to Hoover. The road crossing the dam is a narrow, twisty affair, with traffic backups at the dam crossing common. The Department of Homeland Security has checkpoints on both sides of the dam, conduction searches of large vehicles and RVs to ensure no one is carrying a large bomb or explosives. The loss of the dam would be simply catastrophic, as much of the southwest is dependent on water from Lake Mead, the largest manmade lake in the country. On our trip from the Grand Canyon to Las Vegas (when we also crossed the dam) a DHS agent did a thorough search of the camper, looking into all the large compartments. Semi trucks are not allowed across the dam other than by special permit.

The closer you get to the dam, the slower the traffic and the higher the temperature. Even with the cooling effect of the water in the lake, the heat radiating off the sun baked canyon walls is stifling. On top of the dam the temperature topped out at 116 degrees, the hottest we’ve experienced yet on the trip. The Arizona/Nevada state lines runs right down the middle of the dam, and that is where it was the hottest. Creeping across the dam, you had to wonder how anyone could do construction work in those conditions.

I carry a couple of 5 gallon cans of diesel fuel in the bed of the truck for emergency purposes – gas stations with diesel can be few and far between in the west. Because of this, we weren’t allowed to park the truck in the parking deck on the Nevada side where the tours are conducted. So we had to drive across and park about a ½ mile on the other side of the lake in Arizona. I didn’t mind the extremely hot walk across the dam, (being in hog heaven), but Denise, Vance and Ella were melting. They scooted across in the minimum possible time and hurried into the nice, cool visitor center.

The highlight of tour was the descent 700 feet underground to view the water diversion tunnels, and the generator room. The tunnels were constructed first to divert the Colorado River away from the dam site. After the dam was completed, the tunnels are used to route water to the hydroelectric turbines, and for periods of high water. The water is carried in a set of 13 foot diameter pipes inside the tunnels. The kids got a kick out of the tour guide’s statement that they were ‘inside a volcano’, as the rock forming the canyon walls is of volcanic origin.

After viewing the Nevada side viewing room, we ascended back to the top of the dam and visited a museum about the construction of the dam. There were several great displays on the generation of electricity, demonstrating how rotating a magnet across coils of wire would create an electrical force. This was a prime opportunity to sneak in a little schooling, so I spent some time with Vance and Ella, making sure they understood how a generator worked, and the basic mechanics of high voltage power transmission. Our hope was for them to walk away with some sense of ‘why’ the dam was there, as opposed to view it as a big chunk of concrete with a lake behind it.

The construction of the dam is a great story in itself – nothing on this scale had ever been built before, and the dam was built during the height of the depression. Fighting the killing heat, remote location and sheer scale, the dam was constructed in a little over 4 years – an amazing feat.

We learned some interesting facts. The dam has had two names, originally called Boulder Dam (after Boulder Canyon). Only the dam resides in Black Canyon! The reason for this apparent misnaming - the original appropriations bill for the dam was entitled the ‘Boulder Canyon Project’, as Boulder Canyon was a front runner for the original dam site. However, the Black Canyon site was ultimately determined to the better location, and there the dam sits today. The name was later changed to Hoover Dam to honor President Herbert Hoover.

Another factoid I probably should have learned from my electrical engineering education but didn’t – each insulator on a high voltage line can insulate about 14,000 volts. To roughly determine how high the voltage is on a power line, you can count the number of insulators. We spent a couple of mins counting insulators on the numerous high voltage lines climbing up the canyon walls from the powerhouses, to see if there were enough insulators to carry the 230,000 volts the display claimed. Melting in the heat, Vance and Ella rapidly tired of their geeky uncle’s attempt to understand high voltage power transmission ;-)

The highway is being rerouted – a new arch bridge is under construction high up on the canyon walls in front of the dam. The project is years behind schedule, in sharp contrast to the rapid construction of the dam itself! Once the new bridge is completed, only foot traffic will be allow on top of the dam, greatly reducing the security concerns.

Vance: Hoover Dam was once the largest dam in the world. It was later surpassed by a dam in Washington State. The day we went there we couldn’t park in the deck because we had emergency diesel. So we had to walk across the blazing dam. As the penguin in the movie Madagascar said “Hoover Dam!!”

We went into an old water tunnel which was pleasantly cool. The guide then showed us how the turbines work. Next the tour was at a generator room where the turbines are. We finally took a top view of the dam and headed back for Vegas.

IMAGINE A DAM THAT COULD SURPASS THIS MIGHTY STRUCTURE!