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!
By the end of this lesson you should be able to:
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.
ACTIVITY | LOCATION | SUBMISSION INFORMATION |
---|---|---|
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.
In most places, an unsaturated zone of soil, sediment, and bedrock exist close to Earth's surface. Although it is unsaturated, the zone still may contain water by capillary action and adhesion to soil particles. This so-called vadose zone exists from the soil surface beneath our feet to the top of the water table. This should be relatively easy to understand if you imagine that if all of the soil and sediment beneath us was saturated, we'd constantly be walking through mud, quicksand, etc., dependent upon the parent material. Instead, as water infiltrates into the subsurface, much of it flows to the water table, while some is retained in the soil and sediment column, the vadose zone.
Remember that this unit on water and lesson on groundwater present only a broad overview of some very complex topics. Here you will have an opportunity to revisit and expand your knowledge of some of the topics covered in part 2 of this lesson—I consider the concepts presented here to be important for understanding links between surface and groundwater. To me, these concepts highlight the complex interplay of surface and subsurface processes that are active in and affect the Critical Zone.
Review the following information and resources:
You can learn more about groundwater at USGS [7]. More importantly, you can access a number of resources, including posters for your classroom, at this site. I highly recommend spending time here.
A detailed map of Earth's groundwater resources can be viewed and downloaded at WHYMAP [8].
USGS has placed much of its groundwater database online. In this exercise, you will learn to access this data to gather information relevant to your soil and surface water study site.
For this assignment, you will need to record your work on a word processing document. Your work must be submitted in Word (.doc) or PDF (.pdf) format so I can open it. In addition, documents must be double-spaced and typed in 12 point Times Roman font.
L7_groundwater_AccessAccountID_LastName.doc (or .pdf).
For example, student Elvis Aaron Presley's file would be named "L7_groundwater_eap1_presley.doc"—this naming convention is important, as it will help me make sure I match each submission up with the right student!
Upload your report to the "Lesson 7 - Groundwater Activity" dropbox in Canvas (see the Modules tab) by the due date indicated on our Canvas calendar.
You will be graded on the quality of your writing. You should not simply write responses to the questions and submit them to me. Instead plan on writing a short stand-alone paragraph (or page or whatever you decide is necessary considering any constraints I might have placed on you) so that anyone can read what you've written and understood it. You should strive to be specific and complete in responding to the questions. Your answers should be analytic, thoughtful and insightful, and should provide an insightful connection between ideas. The writing should be tight and crisp with varied sentence structure and a serious, professional tone.
If you have not concluded that the Critical Zone is a complex maze of processes and interactions, you soon will. By now you should clearly understand the links between the atmosphere, climate, and the water cycle. You should have a basic understanding of how water interacts with the lithosphere, though we will explore this in more detail in the next unit. You should also know that freshwater in the Critical Zone is unevenly distributed on Earth and that this leads to variations in the character of and processes operational in the Critical Zone from region to region.
Please read the following manuscript to solidify your understanding of the links between surface and groundwater quality and quantity and the surrounding landscape.
This is an excellent review of much of the material covered in Unit 4—pay particular attention to the schematic figures. Also, note the attention placed on human interactions with the water cycle. As you do so, begin to think about the role of humanity on your study site –(your site is probably not pristine even if it is located in a state or national forest), as you will be required to assess the impact of past, present, and potential future human impacts on your site as part of your semester project.
Let's take some time to reflect on what we've covered in this unit!
For this activity, I want you to reflect on what we've covered in this unit and to consider how you might adapt these materials to your own classroom. Since this is a discussion activity, you will need to enter the discussion forum more than once in order to read and respond to others' postings.
You will be graded on the quality of your participation. See the grading rubric [10] for specifics on how this assignment will be graded.
This lesson on groundwater was crafted to introduce you to the fairly complex concepts of hydrogeology and groundwater flow. You should understand that some water that arrives at Earth's surface infiltrates into the ground. An unsaturated zone exists between the ground surface and the water table, beneath which lies the saturated zone of groundwater flow. Where recharge to the water table occurs freely without barriers to flow, unconfined flow systems exist. In some places, groundwater is confined—disconnected from overlying solid material and water outside of its recharge area. Surface water and groundwater can be in hydrologic communication in other ways, for example as gaining or losing streams.
Groundwater flows through spaces in the sediment and rock beneath our feet: a continuum exists in flow regimes between diffuse flow and fracture or conduit flow. Groundwater quality is affected by natural and anthropogenic processes. In some places, groundwater can be naturally degraded by proximity to geologic materials, but the majority of groundwater quality concerns are due to human activities, such as agriculture, industry, and waste disposal. Because of water's role as a solvent, and its intimate relationship to the sustenance of life, all of the processes you've learned about in this unit are important for furthering your understanding of Critical Zone processes. Remember, agua es vida.
You have finished Lesson 7 and Unit 4. Double-check the list of requirements on the Lesson 7 Overview page to make sure you have completed all of the activities listed there before beginning the next lesson.
If you have anything you'd like to comment on or add to, the lesson materials, feel free to share your thoughts with Tim. For example, what did you have the most trouble with in this lesson? Was there anything useful here that you'd like to try in your own classroom?
Links
[1] https://toxics.usgs.gov/
[2] https://climate.nasa.gov/quizzes/soilmoisture-quiz/
[3] http://www.waterencyclopedia.com/Ge-Hy/Groundwater.html
[4] http://water.usgs.gov/ogw/basics.html
[5] http://en.wikipedia.org/wiki/Aquifers
[6] https://water.usgs.gov/edu/earthgwdecline.html
[7] http://water.usgs.gov/education.html
[8] http://www.whymap.org
[9] http://waterdata.usgs.gov/nwis/gw
[10] https://www.e-education.psu.edu/earth530/node/1650