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Dam-it? I Just Don't Know!?!
by George R. Allen
Boise State University

Grade: 8
Time Allotment: 3 class periods
Subject Matter: History, Geography, Earth Science

 In this lesson, students will analyze two different large dams: the Hoover Dam built in the 1930's, and the Three Gorges Dam currently under construction. Students will compare and contrast the two dams and analyze them from modern and historical perspectives. The goal is to lead students to understand how: human activities change the environment, natural resources are vital to human activity, and how history is a matter of perspective.

To reach these goals students will view portions of the videos Hoover Dam and Three Gorges Dam; create a Venn diagram comparing and contrasting the Hoover and Three Gorges dams; hold a mock debate in which the building of each dam is supported and criticized; and finally write a position paper using Hoover Dam either as support or for opposition to the Three Gorges Dam.

Learning Objectives:
Students will be able to:

  • compare and contrast two similar items.
  • analyze a historical issue from historical and modern points of view.
  • identify ways humans respond to their physical environment.
  • evaluate a course of action keeping in mind the information available at the time.

National Geography Standards:

Standard 14 of National Council for Geographic Education
The students will understand how human actions modify the physical environment.

Standard 5 of the National center for history in the schools
The student engages in historical issues-analysis and decision-making keeping in mind the information available at the time.

State Standards

Geography Standard 3 from Idaho Achievement Standards
The student understands that physical systems affect human activity and living conditions.

Media Components:

  • Hoover Dam, The Making of a Monument. (The American Experience) Dir. Jacqueline Shearer Videocassette. Dist. PBS Home Video, 1999.
  • Three Gorges: Biggest Dam in the World. Perf. Jodie Foster. Videocassette. Dist. Discovery Channel Video, 1998.



Prep For Teachers

  • Prior to teaching this lesson, bookmark the Web sites on each computer you will use in the classroom.
  • Prepare two video machines connected through a splice to one television. If you do not have the technology to do this, prepare two VCRs and televisions or tape the relevant segments to one video cassette in the correct order.

Introductory Activities
Step 1.
Distribute the diagram of large dams. Ask students how many impacts of large dams can be identified in the diagram (17).  Ask them if they can think of any other impacts large dams have. Make a list on the board.

After you have made an exhaustive list of all the impacts of large dams, divide your students into groups of 4-5 and give each group butcher paper. Explain to each group that they are to make a chart with "positive benefits" on one side and "negative consequences" on the other. As a group, students should list all the impacts the class has identified as either "positive" or "negative" and place them in the correct place on the chart. Ask students if any could be classified as both "positive" and "negative." Ask students if they think there are any consequences they didn't think of. Ask them if the "positive" or "negative" classification is a matter of perspective. Can an impact be "positive" for one group of people and "negative" for another?

(Guide students to realize that structures as large as dams have a multitude of impacts and it can be hard to identify all of them. Encourage them to consider how one impact can cause a second impact, which can cause a third. Also lead them to see that what might be positive for a farmer may be negative for a fisherman and that, yes, perspective can matter in assigning "positive" and "negative" labels to the impacts.)

Step 2.
Have groups share their findings with the rest of the class. Direct the other groups to add any new impacts to their lists. Ask them to take note of any differences in labeling. Did one group label and impact "positive" and another "negative?" What groups would tend to see the "positive" impacts of dams? (farmers, engineers, hotels, tourist agencies, big industry, politicians) Which groups would tend to only see the negative impacts? (environmentalists, river guides, riverine communities, fishermen)

(There are approximately 800,000 dams total in the world today. Of these, about 45,000 of them are 500 ft or taller, classifying them as large dams. In the past, large dams were almost entirely viewed as signs of progress and the triumph of human endeavor. But recently many have begun to criticize dams due to their perceived negative effects. Supporters point to the provision of electric power, irrigation for agriculture and water supply. Opponents contend dams favor the wealthy and industry, destroy native fisheries, are not cost effective and even increase CO2 emissions. They have begun to call for the dismantling of large dams. The debate has increased in the past decade.)

Step 3.
Have students access the Internet sites -Wow. Hydropower Sounds Brilliant, or Does It? and Facts About Hydropower. Provide your students with a FOCUS FOR MEDIA INTERACTION by asking them to summarize the arguments of the two sides as presented on the web pages. After your students have read the two pages, check for comprehension and fill in any gaps in their information.

Step 4.
Ask students if they think the debate between opponents and proponents of large dams is easy to resolve. Ask what they might do to solve the controversy and who would be the winner and loser of the settlement.

Step 5.
Ask students if they think the people that built large dams 70 years ago would view the conflict differently. Allow them to brainstorm different possibilities.

Learning Activities

PLAY Hoover Dam video introduction with David McCullough. Provide your students with a FOCUS FOR MEDIA INTERACTION, asking them how the Hoover Dam was viewed when it was constructed and how it is viewed by environmentalists today. START the tape after the Miracle Grow underwriting spot. David McCullough will introduce the historical perspective on the Hoover Dam. PAUSE when McCullough finishes talking about historical antecedents and consequences.

Check for comprehension.

Ask students to expand upon this idea of antecedents and consequences between the Hoover Dam project and the Three Rivers Gorge project. How is the Hoover Dam an antecedent to the Three Rivers Project? How do you think the construction of the Hoover Dam affected the current Three Rivers Project?

PLAY the introduction of the Three Gorges Dam video. The video begins after the Discovery Channel introduction with water flowing down a mountainside. Actress Jodie Foster sets the stage for the Three Gorges Dam project. Provide students with a FOCUS FOR MEDIA INTERACTION, asking them to find similarities between the Hoover Dam project and the Three Gorges Dam project. PLAY the tape until the music starts and the dragon begins to dance across the screen. PAUSE the tape and check for student comprehension. What similarities did the students find?

Provide students with a FOCUS FOR MEDIA INTERACTION, asking them to find further similarities between the two dams. PLAY from the moment you paused until the title of the video, Hoover Dam appears. Check for comprehension.

Ask your students to predict how the Hoover Dam would change the environment around it, as well as the people who worked the dam. Was there anything around the dam before construction began? What developed as a result of construction? Where did the workers come from? Did they stay? If they did, where did they stay? How did they change the land?

Provide students with a FOCUS FOR MEDIA INTERACTION, asking them to pay close attention to how the Colorado River was viewed at the time and what was the solution of policy-makers. RESUME the video and PLAY until Guy Louis Rocha of the Nevada State Archivist explains how the river was viewed as an enemy that had to be tamed.

Provide students with a FOCUS FOR MEDIA INTERACTION, asking them to pay close attention to how the Yangtze River is viewed and what the solution policy-makers have come to. PLAY the Three Gorges video from the time when the title appears on the screen until the narrator says… "They now think they have a solution; to build one of the world's largest dams and tame one of the world's wildest rivers."

Ask your students how the flooding situation along the Colorado in the 1930's compares with the 1998 flood of the Yangtze. Lead them to see that the destruction and misery caused by the wild Yangtze was much the same as the destruction caused by the Colorado.

Explain to your students that the decisions made at the time of the Hoover Dam construction must be taken in context. The river was an enemy that destroyed cropland, ruined lives and cost millions of dollars. In the same way the Yangtze is viewed by many Chinese as an enemy that almost destabilized the Chinese economy and killed thousands of people in its '98 flood.

PLAY about 20 min. ahead into the Hoover video from where you left off. Show the students how the dam was constructed by using diversion tunnels and coffer dams. PLAY about 4 min. ahead into the Three Gorges video from where you left off. Show the students how the dam was constructed by using a diversion canal and coffer dams. STOP when the scene changes to the cranes far above the construction site.

Ask the students if the basic method of dam construction has changed much in the last 70 years.

Provide students with a FOCUS FOR MEDIA INTERACTION, asking them to pay close attention to how the Hoover project and the Three Gorges project differ.

PLAY the Three Gorges video beginning another 15 min. from where you left off, when the scene shifts from the shipping of the Yangtze to a city of nearly 1 million inhabitants along the river's shore. STOP the video about 5 min. later just after the graphic which demonstrates what will happen to the city when the reservoir fills and covers it. PLAY the Hoover video from the place you last paused until Tommy Nelson comes on to talk of his experiences as a worker. STOP the video just before Tommy begins to talk about being a trumpet player.

Culminating Activity

Step 1.

Divide your class in half. Assign one group the task of attacking and Three Gorges project as something wholly different from the Hoover project, something that must be evaluated on different terms. Assign the other group with the task of defending the project as similar in basic nature to the Hoover project and a project that will ultimately benefit the Chinese people as the Hoover project benefited America.

Step 2.
Provide each group with a Venn Diagram to compare and contrast the Hoover and Three Gorges project. Instruct each group to list all the attributes particular to only the Hoover Dam in the circle representing it, the attributes particular to only the Three Gorges Dam in the circle representing it, and the attributes they both share in common in the middle portion that overlaps.

Then instruct the students to create a large Venn Diagram on butcher paper with large print and colors to be used in the presentation of their position.

Step 3.
Create a mock public debate. Group A is to select their best "lawyer" and provide him/her with notes and briefs to best defend their position. Group B is to select their best "lawyer" with accompanying information to best defend their position. The teacher acts as the mediator, asking difficult questions to the two representatives and sparking debate between the two.

Encourage students to argue from a historical perspective considering the knowledge available at the time. Also encourage them to argue from the perspective of different physical and human environments at each site.


Calculate how more more/less electricity in your community would cost if you did/did not have access to hydroelectric energy. How would this affect local businesses?

Language Arts
Write a persuasive essay to the newspaper arguing for or against hydroelectric energy in your area.

Visual Art.

Research the various pictures of dams from around the world on the Internet.

Community Connections:

  • Visit local dams in your area. Arrange for a tour of the dam and investigate the inner workings of the structure. Then walk around the outside of the dam/reservoir complex and look for signs of change in the local environment. Create a Powerpoint presentation with photos of the trip and photographic evidence of the changes wrought on the local environment by large dams.
  • Interview a farmer in the community that depends upon irrigation from large dams for his/her livelihood. Ask the farmer what he/she would think of dismantling the dams. Then interview a river guide or a fishing guide and ask him/her the same questions. If at all possible, have the two representatives visit the class.
  • How does energy get to your classroom? Take students on a tour of the local electric company and study your city's electrical grid. Encourage students to learn where the energy for their city comes from. How much does it cost? Could it be attained more cheaply if there was/wasn't a dam in the area? How would the city change if there was/wasn't a dam?
  • Early dam builders never thought about the harmful consequences of the dams they were building. For them, they were doing a service to society by taming part of the wild and dangerous nature. Are there ways in which we are so obsessed with progress today that we could be creating environmental tragedies and not realize it?

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