Dam Trip

December 17, 2010

My fall vacation was just beginning with the conclusion of the ASCE conference.  My wife had her own professional Translators’ conference to attend the following week in Denver.  We decided to rent a car and drive from Las Vegas to Denver.  On the way we stopped at the Hoover Dam, the Grand Canyon, and Mesa Verde.  In between the monuments, we drove past some of the most varied and beautiful countryside.

As we drove out of Las Vegas, I was anxious to be on our way to see these sites.  After several days in the City of Lights, it was time to get out and see something real.  Real important, real historic, real big.  The Hoover Dam fit the bill.

We arrived from the West.  Lake Mead was visible long before dam came into sight, and we could see how the residents have taken recreational advantage of the man-made lake.  I was really surprised by the its size.  Even though the lake’s depth was near record lows, I could not fathom the immense volume retained by the Hoover dam nor, for that matter, the acreage that would have been submerged in order to create such a reservoir.  With capacity for 9.2 trillion gallons, it is America’s largest man-made reservoir.

Our first opportunity to view the dam actually came from the pedestrian walkway on the new bridge that bypasses old the dam route.  The bridge opening had just been celebrated earlier that week, so we were among the first people to get such a view.

The pathway to the bridge overlook included several plaques that described in great detail the design and construction process required to span the gorge.  An elaborate cable-supported cantilever system was employed during construction, so that work on the arched bridge proceed from both abutments simultaneously.  In it’s final form, the bridge appears much less dramatic, comprising only a simple concrete arch with slender piers that support the roadway.  The arch of the bridge compliments well the water-retaining arch of the Dam itself.

Continuing down the narrow roadway to the Dam, I nearly drove off the road distracted by the elegant bridge structure.  At the bottom of the ravine, we pulled into a new parking structure and proceeded to the Hoover Dam Visitor Center.

Although I had hoped to take the entire tour, because I had missed the ASCE led tour earlier in the week, we simply did not have time.  Instead, I settled for the quick $11 tour which took us down to the bypass tunnels and then the generating station.

First, we were ushered into a small theatre to hear some background about the Hoover Dam.  I was surprised to learn that the entire intent of the project was to create a reservoir and regulate the flow of the Colorado River.  By the 1920s developments along the Colorado River were continually at risk by seasonal inundations.  I was pretty disappointed by the partisan portrayal of the Dam’s effects.  The movie, probably made in the 60s, paid no attention to the consequences of such drastic river control measures.  I mean, perhaps the State should have guided settlement away from the flood plains instead of forcing Mother Nature to comply with our zoning desires.

Today, more than one million acres in America and half a million acres in Mexico are irrigated because of the Hoover Dam and related down-stream systems.  The development of such southwestern cities as Las Vegas, Los Angeles, San Diego, Phoenix, and Tuscon would likely not have been possible without this initial investment in the Bureau of Reclamation – the national body that manages the dam.

Following the video, our tour guides escorted us into a large elevator.  As we descended several hundred feet, the bell-hop had time to tell several terrible jokes.  At the bottom, we entered a mine corridor leading to a single congregating room.  In the center of the room another guide used a model of the underground system to illustrate how water travels from Lake Mead, into the dam’s intake towers, through the generators, and finally downstream into the Colorado River.

From this observation room, we could see through glass windows down to several gigantic pipes.  The guide went on to explain that those were two of the original bypass tunnels for redirecting the river during construction.  It had never occurred to me before how monumental that task must have been.  Two of the four original bypasses are still in service as floodways, in case the volume of water ever exceeds the dam’s capacity.

Another short trip in the elevator took us down again to the generator room.  This is the very famous room that’s so often pictured in articles about the Hoover Dam.  In fact, you’re only seeing the very tops of massive generators that are propelled by water rushing past the paddles several more stories down.  The tube that wraps around the paddles actually reduces somewhat in diameter in order to maintain a constant pushing velocity.

The generators were an afterthought.  Our tour guide explained that, of the five States contributing to the dam project, California was alone unable to meet its funding commitment.  A compromise was reached wherein California would cover the cost only of installing the hydroelectric generators and then sell back the energy to offset their debt.  The States have long since recouped the $165 million construction cost, and today 1.3 million people are served by energy produced at Hoover Dam.  And since it’s a public entity, the electricity is sold only at cost.  The guide was also careful to point out that the Las Vegas casinos do not receive any of the power output from the federally funded plant.

We finally boarded the elevators for a third time to return to the top of the dam and the visitor center.  A brief exhibit explained more of the particulars of the dam construction and its builders.  The project was authorized in 1928 and commenced in 1931.  Despite harsh working conditions and a remote location, tradesmen desperate for work flocked to nearby Boulder City and hoped to get work on the Dam.  Several workers died during construction, doing risky tasks that we would not conceive of in this day-and-age.  Such commitment, however, enabled the project to be completed two years ahead of schedule.

We ended our trip with a drive over the dam, which despite terrorism concerns is still open to public traffic.  From there it was back on the road.  Our next stop would be the Grand Canyon.

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