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The Hoover Dam
By Allison Pirie
 even
hundred twenty six feet high. One thousand two hundred forty four
feet across. Six hundred sixty feet thick at the base. Forty five
feet thick at the top. Four point four million cubic yards of concrete
inside the structures. Forty five million pounds of reinforcing steel.
Even just looking at these numbers you know that this is an impressive
structure. In fact, the Hoover Dam has been named one of the seven
modern engineering wonders of the US, as well as a Civil Engineering
Monument of the Millennium by the American Society of Civil Engineers
(ASCE). And for good reason.
 onstruction
on the Dam began in 1931, with a primary purpose not of power, as
one might think, but flood control of the Colorado River, and ended
in 1936, with the last concrete being poured in September of 1935.
In addition to flood control, the other purposes of the dam include
navigation, irrigation, water storage, and of course, power. On the
dam is a monument depicting each one of these uses. The actual construction
type is what’s called “concrete arch-gravity type”,
meaning that its curved shape causes the water to be carried by gravity
and the horizontal arch. The dam itself was built across Black Canyon
with giant concrete blocks varying in size. Over 16,000 men and women
worked on the dam during the five years, working 24 hours a day to
complete the project. Being built during the Great Depression, the
project created many jobs, and thousands of people moved to the area
specifically for the opportunity to work. Sadly, 96 people lost their
lived during construction, from such things as accidents, carbon monoxide
poisoning, and heat. Contrary to stories you might hear, no one is
buried inside of the dam.
[
The Hoover Dam Gallery 1 ]
 s
expected, power is one of the main purposes of the dam. What may be
surprising is where the power goes. Arizona gets almost 19% of the
power generated, Nevada gets almost 24% of the power generated, and
the rest of the power is distributed among various cities in several
states. Southern California alone receives 56% of the power generated,
with Los Angeles, California, as one of the largest recipients of
the power, receiving almost 16% of the power generated. Surprisingly,
Las Vegas, a city that is only 30 miles away and has an obvious need
for a lot of electricity, only gets about 4% of its power from the
Hoover Dam. Why you might ask? When the Hoover Dam was built, Las
Vegas was a small railroad town, without the need for the electricity.
 nside
of the bottom of the dam is a massive powerplant, which takes up a
total of 10 acres of floor space, with 17 main turbines inside of
the generator rooms, which along with service stations units, produces
about 4 billion kilowatt hours of electricity each year. This powerplant
is also viewable from the top of the dam, looking over the side. Along
the dam there are four intake centers (two in Arizona, two in Nevada).
These centers hold roughly one quarter of the water used in the powerplant.
How does all of this get paid for? All of the costs to upkeep and
run the dam are paid for with revenue from the power generated and
sold.
[
The Hoover Dam Gallery 2 ]
 ake
Mead, a reservoir created by the construction of the dam that covers
247 square miles and holds roughly 326,000 gallons of water, or enough
water to cover the state of Pennsylvania with a depth of one foot,
is the largest manmade reservoir in the United States. Not only does
the reservoir provide water to millions of people, but it's also a
prime place for recreation, including boating, rafting, and water
skiing to name a few.
 ut
what Lake Mead is really known for is the water that it provides to
the western states. In Las Vegas, for example, 88% of the water used
in the city comes from Lake Mead. When the Hoover Dam was built, the
states involved that would get water, all signed a contract for 75
years that would determine where the water is allocated. In October
2003 Gail Norton, Secretary of the Interior, and the Governor’s
of all of the states involved, all met at the Dam to sign the Quantification
Settlement Agreement. What this does, is reassign the amount of water
that states are allowed to use. For example, California has been using
more than their amount, so in this agreement they agreed to reduce
their amount of water that they use. Additionally, when the agreement
was signed, it was not anticipated that Nevada, especially the city
of Las Vegas, would need the amount of water that they needed. Therefore,
one of the changes in the agreement is that Nevada will be able to
take additional water if needed, as long as the other states do not
use all that their allotments.
 f
course, being in a desert, you would expect that the area is undergoing
drought conditions. Lake Mead is currently 80 feet below its normal
level. When looking at the sides of the rock walls, you can see white
lines surrounding the water. That level is the high water mark of
where the water level reached in 1983. Since that time, the water
has receded, leaving salt deposits on the side of the rock that have
since been bleached by the sun, turning them into a white “bathtub
ring” around the lake.
[
The Hoover Dam Gallery 3 ]
ne
question that a lot of people have about the dam is does water go
over the top? The answer to that question is no. On either side of
the dam is a spillway, the Arizona Spillway and the Nevada Spillway,
named for the states where they are located. The spillways are dry
right now, but when the water is high enough, it goes into these spillways.
 he
Hoover Dam is one of the top tourist destinations, even though it
is “in the middle of nowhere.” Over four thousand people
visit the Dam every day. When you visit you can walk across the dam,
see one of the four intake centers, or take a tour of the dam. And
you can even go up into the observation tower for a breathtaking view
of the Dam. One tip… the water you see in the tunnels during
the tour – it’s not a leak. It’s seepage. A leak
is a much more serious thing.
 nowing
all of this, it’s little surprise why the ASCE named it one
of the seven modern engineering wonders of the US. What’s surprising
is the intense feeling that you feel when walking over it, or even
just looking at photographs of it. There are tons of jokes you can
make about dams. (What did the fish say when he walked into a wall?
Dam.) The Hoover Dam is no joke.
[
The Hoover Dam Gallery 4 ]
Facts and figures courtesy of USBR, ASCE, and the Hoover Dam Magazine.
For more information about the Hoover Dam and Lake Mead, check out
the following websites:
 The
Hoover Dam Official Website
American
Society of Civil Engineers Hoover Dam Site
Lake Mead National
Recreation Area
60
Dams in 9 States to Come Out in 2001
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