Rivers have always been an essential part of life on earth, ever since life began. Many of our greatest cities were built and grew up around rivers. In this activity, you will learn about the large rivers and their part in the water cycle.
Go to The Nature of Great Rivers and read the "Why Don't Rivers Run Dry?" section. Once you have finished that section, go to the Hydrologic Cycle, where you can go through an excellent, animated visual guide to the processes of the hydrologic cycle. Rivers depend on all parts of the cycle. After you go through the water cycle, you should be able to answer these questions:
- What parts of the hydrologic cycle put water into the river?
- What parts take water out of the river?
- Can people increase or decrease any parts of the cycle? How?
- Is there anything in your neighborhood that changes the water cycle? (Hint: think especially about runoff and how things such as pavement or vegetation might change it).
Now go back to The Nature of Great Rivers and read the "Why Do Rivers Carry Stuff?" section. As you are reading, think about answers to these questions:
- Where does the stuff that rivers carry come from?
- What kinds of landscapes produce the most eroded materials?
- What happens when river water slows down?
- Which particles settle out first?
- What is the river bed?
- How do rivers make their beds?
- What is the energy source for all of this bed-making work?
- What kind of river bed would you expect in the upland portions of a river, and why? What is the floodplain?
- When the river gets out of its banks, what kinds of materials are likely to be deposited on the floodplain?
Now, go back to The Nature of Great Rivers and read the "How Do Rivers Make Their Beds?" and the "How Do Humans Influence River Beds?" sections. Think about answers to these questions as you are reading:
- How can humans change the normal balance between the natural processes of erosion and deposition?
- What happens to the river when humans take these actions?
- What is "hungry water" and how does it affect the river?
- How do humans change the timing of river flow patterns?
This esheet is a part of the Great Rivers 1: The Nature of Great Rivers lesson.