Water, Rivers & Topography
computer exercisesuggested grade levels: 9-12
view Idaho achievement standards for this lesson

Overview:
Without water from irrigation and wells many places now inhabited in Idaho would probably be barren (of people as well as farms). The river drainage in southern Idaho has been influenced by the changing topography over the last twenty million years. Ground water is just as important as surface water in Idaho. The following exercises are designed to increase awareness of these systems.

Procedure:
Answer these questions below:
1. Rivers and drainages:
   a. Using the Eastern Idaho and Southeastern Idaho drainage and mountain range maps, inspect the courses of the major rivers.
   b. Which direction do most of the rivers south of the Snake River flow until they reach the Snake River? What about the Portneuf and the Bear Rivers? Which way are they flowing? What caused this unusual drainage pattern?
   c. What rivers north of the Snake River flow south and join with it, and which do not? If they do not flow into the Snake River where do they flow?

2. The Yellowstone Hot Spot:
   a. The Hot Spot is now north and east of the Snake River Plain and forms a topographic high. Rivers flow away from Yellowstone. Now imagine that the Yellowstone Hot Spot is near Pocatello. How would the hypothetical presence of a topographic high like Yellowstone at Pocatello affect the rivers that now flow into the Snake River near Pocatello? Visit drainage development to find the answers.

3. "Natural Landscaping". The landscape near Pocatello was dramatically modified in just a few weeks fifteen thousand years ago. Visit the Lake Bonneville Flood to answer these questions:
   a. Where did the water come from?
   b. Where did it go?
   c. What major changes to the landscape were caused by the Bonneville flood?
   d. Could we have another Bonneville flood? What conditions would have to exist for this to occur?

Related Lesson Topics:
Hydrology: Hydrology Topics

Lesson Plan provided by Vita Taube, 2000
Idaho Achievement Standards (as of 7/2001) met by completing this activity:
357.01