hoover

1. Virtual Field Trip
(Spring Break 2007)

2. Hoover Dam
• Hydroelectric facility
• Located on the Colorado
River on the Arizona/Nevada
Border
• Construction started in 1931
• Dam was completed in 1935
two years ahead of schedule
and under budget!
http://www.sdsuniverse.info/story.asp?id=3713
http://www.usbr.gov/lc/hooverdam/service/index.html

3. Dam Data
• Arch Gravity Dam
• 726 feet tall
• 1244 ft long
• 45 ft wide at the top
• 660 ft wide at
the bottom
• 3.25 million cubic
yards of Concrete

4. Bird’s Eye View

5. Power plant Facts
• The power plant at
the base of the Dam
has 17 Commercial
generating units.
(shown on next slide)
• Capable of generating
2080 Megawatts

6. Nevada Wing with 8 Generators

7. Schematic of the Dam

8. • There are 4 intake towers
• 2 on the Arizona side and 2 on the Nevada side.

9. How power is Generated
• Water passes through
screens on the intake
towers and flows through
the penstocks (30 ft in
Diameter) to the
generators falling an
average of 420 feet.
(head)
• Water reaches a speed of
85 mph by the time it
reaches the generators.
http://en.wikipedia.org/wiki/Hoover_Dam

10. • Water from the Penstock
turns a shaft on the
generators.
• Rotors, made up of
electromagnets, are
connected to the shaft
and spin around a coil
of copper wire,
generating an electric
current.

12. Hoover Dam Can Generate 2080
Megawatts

13. Transmission Lines
Lines Deliver
power to NV,
AZ and CA

14. Lake Mead
• Flooded The Black
Canyon of the Colorado
River
• Covers 247 mi 2
• Popular recreation spot
for boating, fishing and
water sports
• Flooded many small
communities including
St. Thomas NV.
• White bathtub ring marks
the 1983 high water mark
result of the 1982-3
El Niño

15. Before the Dam: Black Canyon
http://www.library.unlv.edu/early_las_vegas/hoover_dam/short/0015_0020t.jpg

16. St. Thomas
• Founded by Thomas Smith, a Mormon
settler in 1865. The town was a farming
and business community until 1938 when
the area was flooded by Hoover Dam, as
Lake Mead filled.
http://www.nps.gov/archive/lame/stthomas.html

17. Diverting the River
http://www.usbr.gov/lc/hooverdam/images/p45-300-02371.jpg

18. Construction at Night, July 1934
• To learn
more about
the
Construction
of Hoover
Dam visit
this website:
http://www.ecommcode.com/hoover/hoov
eronline/hoover_dam/const/toc.ht
ml

19. Endangered Fish
• At least two species of
fish have had a major
decline since the
construction of Hover
Dam, the Razorback
Sucker (right) and the
Bonytail (left)

20. Bonytail
This fish was listed
as endangered in
1980. There are no
known breeding
populations left in
the wild.
Reintroduction is
happening through
stocking in the
areas shown on the
map.

21. Razorback Sucker
This fish is limited to
25% of its original
range. Most of the
population consists of
adults due to low
survival rates of
young fish. The
hump on the fishes
back provides stability
in turbulent water.

22. Reasons for decline
• Alteration of the Colorado River system from a
turbulent river to a series of calm reservoirs and
channelized reaches
• Nurseries of the fish have been flooded
• Dams block upstream migration
• Non-native sport fish
• Lack of warm seasonal flow, water from the
dams is always cold.
• Other introduced animals, plants, pathogens
and contaminants.

23. Information on Endangered Fish
• http://mountain-
prairie.fws.gov/ea/infopackets/coloradoriver/CR
RPfacts.pdf
• http://mountain-
prairie.fws.gov/ea/infopackets/coloradoriver/
• http://biology.usgs.gov/s+t/imagefiles/r166f03.ht
m
• http://biology.usgs.gov/s+t/noframe/r166.htm
• http://heritage.nv.gov/images/2003/gilele80.jpg

24. Downstream
• Water in the Colorado
River is always cold
• Flooding no longer
scours the banks and
exotic species such as
tamarisk have become
common
• Fertile silt in no longer
deposited during
floods