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Your Mission
Change your perspective—to a geographic perspective.
Traces of the Past
Places and people on the Earth differ from one another in significant ways. To describe and explain the world, geographers draw upon findings from many related fields, while keeping in mind the big picture—the interconnection of people, places, and things. Part of the “big picture” of geography is recognizing that differences exist, and looking at why differences exist. A geographic perspective helps to analyze controversial environmental issues, such as whether or not to build a dam or tear down an existing dam. Get the “big picture” of part of Africa’s Zambezi River, where the effects of two dams spread far beyond the boundaries of the river.
Africa’s Zambezi River, one of the world’s major rivers, flows through or forms the border of six countries. It is restrained by two dams. The Kariba Dam, which was completed in 1960, is at Kariba, in Zimbabwe. The Cahora Bassa Dam, built in 1974, is at Cahora Bassa, in Mozambique.
Locate the Zambezi River on a map. As a result of the two dams, large lakes, or reservoirs, were created where only the river used to flow. Locate the lakes on the map. Then follow the
instructions on the handout with the two maps to see how the Cahora Bassa Dam changed the river and the nearby land. (Download a free copy of Adobe Acrobat Reader to view this file.) (The maps on the handout show just one portion of the Zambezi River.)
The map you just created shows a small part of the picture. To get the bigger picture, you’ll need to think like a geographer.
Hydropower to the People
A dam affects not only a river, but the land, and the people and animals who depend upon that river.
The Kariba Dam provides hydroelectric power to large portions of Zambia and
Zimbabwe. People there can now enjoy lighting and refrigeration. The dam provides flood control. Wildlife and tourists are drawn to Lake Kariba.
But Lake Kariba, which formed as a result of the dam, flooded a gorge where the Tonga tribe lived, and the Tonga were forced to leave their home. Annual flooding used to renew the soil on farmland, but both the Kariba and the Cahora Bassa dams have stopped the yearly floods, and as a result the land is less fertile. The changing water level below the dams makes navigation difficult and means that people and wildlife can’t count on a steady level of water. Animals that used to be plentiful, such as rhinos, became scarce. (Rhinos are already at risk; they are killed for their horns, which are sometimes ground and sold as medicine, or used to make daggers.)
To understand the impact of a dam on a river system, you’re going to do some research in a small group. Your group will look at the changes to the big picture: for example, to agriculture, water quality, flora and fauna, standard of living, tourism, trade, culture, and the economy.
You can find two articles on the Zambezi River at Britannica.com:
Several travel agencies offer helpful information (be aware, however, that commercial sites are likely to present only a positive viewpoint):
Picture This: Looking at Pros and Cons
A geographer organizes and displays the geographic information he or she has collected in ways that help analyze and interpret the data. Geographers use a variety of ways to show data visually, such as maps, graphs, diagrams, tables, spreadsheets, time lines, photographs, aerial photos, and drawings.
To share the results of your research with the class, your team should make a display of your findings in a way that you think will interest your classmates. Focus on conveying the interconnections between the river, the land, the people, and the wildlife. Choose one member of your team to explain the rationale behind your display to the class.
Practicing conservation, whether of rivers or condors,
doesn’t mean that people shouldn’t make changes to the environment. Dams, highways, factories are a part of our lives. The goal of conservation is for the benefits of any change to outweigh the damage of that change. Conservation efforts may minimize damage and sustain the system for future use.
Take Action—Geography Action!
You can have a positive impact on the health of rivers in the United States! The American Rivers Web site lists key issues and instructions for contacting members of Congress or other officials. (American Rivers)
Along the Zambezi, people were forced to relocate because of the dams. Survival, an organization that supports tribal people through public campaigns, helps tribes in need. Go to http://www.survival.org.uk/index2.htm and click on Campaigns, then under Campaigns Achive, click on Arranged by Campaign, for issues, such as the potential effects of a dam on the fate of the Himba, in Namibia and Angola. (Survival)
Closer to home, take action through the National Wildlife Federation, which updates the status of proposed projects that will affect conservation, and includes instructions for sending your comments to interested parties. (National Wildlife Federation)
Whatever you decide to do, tell us about it! Fill out the Geography Action! survey, and learn what other students are doing for rivers!
Mapping activity from “Down the Zambezi” Geoguide lesson plan. © 1997 National Geographic Society. Maps by Martin Walz.
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Photographs (left to right): Lower Monumental Dam, Snake River, Washington, by Richard S. Durrance; Ross Dam, Skagit River, Washington, by James P. Blair; Sierra Newt, California, copyright Corbis
© 2001 National Geographic Society. All rights reserved.
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