Family Activities: Fifth-Eighth Grade
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An Imaginary Reservoir

Before a dam is built, people have to consider how the dam and the reservoir it creates will alter the landscape.

Find a stream or river near your home and follow it along its course. Pick a location where you can imagine a dam. How wide would it be, and how high? Is there a suitable anchor, such as sound bedrock, on which the dam could be constructed?

Imagine the reservoir created by the dam. To get a sense of its size, decide how deep the water should be in the reservoir, then climb up one of the banks until you are that far above the present surface of the stream or river.

Walk upstream, staying as much as possible at the same level. The surface of a reservoir is nearly flat, so if you stay at the same elevation while you walk, you’ll actually trace the shoreline of your imaginary reservoir! Would the reservoir be large or small? Do you have time to walk all the way around, or would you have to walk for a very long time? Would your reservoir submerge any roads or homes?

Note the point upstream where you cross to the other bank, since this is where the stream or river would enter the reservoir behind your dam.

As you walk, you can ponder these questions:

• What effect would the dam have on the land upstream?
  
• What happens to the people and animals upstream of a dam?
  
• What happens to the water while the dam is being built?
  
• What would happen if there were a leak in the dam?
  
• What happens to the river or stream below the dam?

Mary T. Steuwe of Carson Middle School in Tucson, Arizona, contributed family activities for this Geoguide.