The Critical Zone

Lesson 7 Introduction


Lesson Overview

So far you've learned that the water cycle includes the infiltration and flow of water into and through the subsurface. Many citizens are familiar with groundwater, since approximately one-third of us obtain our drinking water supply from groundwater. People discuss "aquifers," underground lakes, and the mythical existence of a deep underground connection between Loch Ness (Scotland) and Lake Champlain (Vermont) that explains reports of large ancient dinosaur-like creatures in both places. However, groundwater is no mystery! The presence and flow of groundwater are governed by the same physical processes that operate within our view on Earth's surface.

In this lesson, we will spend some extra time considering the water that exists beneath our feet. First, you will read about and consider soil moisture in the unsaturated zone, and then progress to read about and study groundwater. You will access, use, and interpret online groundwater data very similar to what you accomplished in your surface-water study in the last lesson. Finally, we will close by thinking in more depth about the links between water, the water cycle, and the Critical Zone!

What will we learn about in Lesson 7?

  • The difference between soil and groundwater, and the vadose and saturated zones
  • Basic concepts of groundwater flow
  • How the water cycle is linked to biologic (including humans) and other processes active in the Critical Zone
  • How to access and use online groundwater data

Learning Objectives

By the end of this lesson you should be able to:

  • Describe soil moisture and the vadose zone, the water table, groundwater, and the saturated zone using a schematic cross-section
  • Obtain and interpret online groundwater data
  • Discuss the important role of water in the Critical Zone

What is due for Lesson 7?

Lesson 7 will take us one week to complete. As you work your way through these online materials for Lesson 7, you will encounter additional reading assignments and hands-on exercises and activities. The chart below provides an overview of the requirements for Lesson 7. For assignment details, refer to the lesson page noted.

Please refer to the Calendar in Canvas for specific time frames and due dates.

Lesson 7 assignments
Report (6–7 pages) on groundwater studies page 4 Post to the Lesson 7 - Groundwater Activity dropbox in Canvas
Discussion—Teaching and Learning About Water page 6 Participate in the Unit 4 - Teaching and Learning About Water discussion forum in Canvas


If you have any questions, please post them to our Questions? discussion forum (not e-mail), located under the Discussions tab in Canvas. I will check that discussion forum daily to respond. While you are there, feel free to post your own responses if you, too, are able to help out a classmate.