Windows into Wonderland

Hotwater eTrip: River Run


Language Arts


The student will:

  • Identify the course of the Yellowstone River on a map of Yellowstone National Park and identify with 100% accuracy at least two locations on the map through which the river passes.
  • Review the water cycle and describe the cycle of the Yellowstone River from beginning to end with 100% accuracy.
  • Identify the watershed of his/her home with 100% accuracy.
  • Be exposed to an alternate version of the origin of the Yellowstone River from the Shoshone culture.
  • Identify and describe, in writing, the course of one other Yellowstone stream.
  • Invent a legend describing the origin of a selected Yellowstone stream.


  • Attachment A - Map of Yellowstone National Park (1.4MB pdf)
  • Attachment B - River Run Worksheet (10KB pdf)
  • Map of the United States
  • Colored and regular pencils


The water cycle is the journey of water as it moves from land to sky and back again. Heat from the sun evaporates water from the surface of the Earth (oceans, lakes, rivers, etc.) and plants transpire, or lose water to the air. This water vapor condenses into clouds. Precipitation is triggered when the clouds meet cooler air and the water returns to the Earth’s surface in the form of rain or snow. Some of the precipitation soaks into the ground and is called groundwater, but most of the water (either above or below ground) flows downhill, makes its way into a watershed (an area from which surface water drains into a river system or other body of water), and eventually ends up in the Earth’s oceans.

Most of the water in the Yellowstone River begins as snow. The source of the river is near the continental divide in the mountains of northwestern Wyoming. The river flows northward through Yellowstone National Park, entering and exiting Yellowstone Lake and tumbling over the Upper and Lower Falls, and on through the Grand Canyon of the Yellowstone. The current canyon dates back to the end of the last glaciation, 14,000 years ago. Melt water from glacial ice carved the current V-shaped valley and today the Yellowstone River continues to erode hydrothermally-altered volcanic rocks.

After leaving the park, the Yellowstone River flows into the state of Montana, collecting water from such tributaries as the Gardner, Bighorn, Powder, and Tongue Rivers. At 692 miles (1154 km), the Yellowstone River is the longest free flowing stream in the contiguous United States. It eventually merges with the Missouri River in western North Dakota.

The Missouri River, approximately 2,315 miles (3,725 km) in length, is the longest river in the United States and drains approximately one-sixth of the North American continent. The Missouri flows into the Mississippi River north of St. Louis, Missouri. The Mississippi River system drains most of the area between the Rocky Mountains and the Appalachian Mountains and empties into the Gulf of Mexico about 100 miles (160 km) downstream from New Orleans, Louisiana.

A legend paraphrased from the Shoshone tribe gives another view of the origin of the Yellowstone River:

Long ago there was no river in this part of the country. A man came from the south and climbed a mountain in the area that is now called Yellowstone. There the man found an old lady carrying a basket of fish. The man was hungry and demanded that the old lady boil some fish for him. She said she would feed him, but warned him not to bother her basket. The man, being impatient, would not listen, and stepped on the edge of the basket. Water and fish spilled out, covering the land, and no matter what the man did, he could not stop it. The man piled rocks to hold back the flood, but the water broke his dam and rushed onward. That is where the Upper Falls of the Yellowstone is today. The man ran faster and built another higher dam of rocks, but it too was unable to contain the water and today is known as the Lower Falls of the Yellowstone. The water gouged a deep channel in the land, forming the Grand Canyon of the Yellowstone River and continues to flow to this day. The big fish basket that the man tipped over became Yellowstone Lake and the old woman with the fish was Mother Earth.*

    *The legend is paraphrased from this reference:
    Clark, E. 1966. Indian Legends of the Northern Rockies. Norman, Okla.: University of Oklahoma Press.


The instructor will:

  1. Review the water cycle with the students.
  2. Ask students to define a watershed and, if needed, provide a definition.
  3. Provide students with copies of Attachment A: Map of Yellowstone, and ask students to locate the Yellowstone River and trace its course throughout Yellowstone National Park, highlighting Yellowstone Lake, the Grand Canyon of the Yellowstone, and the river’s union with the Gardner River at Gardiner, Montana.
  4. Select a student(s) to trace the course of the Yellowstone River on a map of the United States to the point where it converges with the Missouri River, then continue on the course of the Missouri River until it converges with the Mississippi River, and finally continue the course of the Mississippi River and identify the river’s end at the Gulf of Mexico. Remind students that water in the Yellowstone River that began as snow in the mountains in northwestern Wyoming eventually ends up in the Gulf of Mexico.
  5. Instruct students to locate their home on a map of the United States and ask if they live somewhere along the watershed of the Missouri or Mississippi Rivers.
  6. Have students identify the course of a stream in their own watershed.
  7. Instruct students to write or draw a complete water cycle of the Yellowstone River on Attachment B: River Run Worksheet.
  8. Tell students that different cultures may have different, non-scientific views regarding the origin of rivers or other landforms and share the Shoshone legend described above.
  9. Ask students to select another Yellowstone stream. (Suggestions include: the Firehole, Snake, Lamar, Gardner, or Lewis. Download more maps of Yellowstone from the park website, including a larger version of the pdf map included with this lesson plan.)
  10. Direct students to describe, in writing, the course of the stream on Attachment B. Students should describe the location of the stream’s origin, its confluences with other rivers, and the body of water that receives it.
  11. Instruct students to write an alternate explanation in legend format to explain the origin of their stream on Attachment B.


River Run Rubric (41 KB pdf)

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