Unit 6: Groundwater Availability and Resources
Students will utilize the desert Southwest region of the United States and the Ogallala Aquifer in a case study to evaluate issues regarding groundwater and its scarcity. Groundwater is often seen as a limitless resource in the Southwest since there is little regulation controlling the amount that is withdrawn (Rule of Capture). This mentality has led to overuse and to the dwindling supply of groundwater in many parts of the Ogallala Aquifer. This module will help students connect groundwater's role in the hydrological cycle to issues of inequity that can occur when groundwater is not properly regulated.
Unit 6 activities support the module goals of being able to articulate the principles of environmental justice as they relate to examples of water scarcity and contamination using the Ogallala Aquifer in the United States as a case study. This unit also discusses potential solutions to inequitable access to clean water in the Ogallala. The specific learning objectives for this unit are as follows:
- Students will be able to discuss the relationship between the hydrological cycle and availability of groundwater resources.
- Students will be able to predict if a region's groundwater availability is of concern.
- Students will be able to explain how groundwater resources can be depleted.
- Students will be able to obtain data to assess changes in groundwater levels.
Context for Use
This unit may be used for one day of instruction in an introductory geology, environmental studies, or global change class. It can be customized to meet different classroom formats and times. The unit communicates the critical need for management of fresh water and ways in which the students may take part in its conservation. It is designed for a 50-minute course but can be modified to fit various schedules. Students should have been introduced to the concepts of environmental justice and the hydrological cycle prior to this lesson.
Description and Teaching Materials
Unit 6 Pre-class Homework: Using USGS Data to Predict Groundwater Depletion
USGS Groundwater Activity (Microsoft Word 3.6MB Aug14 24) ( or in PDF (Acrobat (PDF) 555kB Aug14 24)). This activity introduces students to groundwater data collected by the USGS and asks them to investigate groundwater depletion issues in a region of Texas. The activity addresses the current state of depleted groundwater in northwest Texas. Over the past decade, persistent droughts in northwest Texas have led farmers to pump more irrigation water from the one of the largest underground water reserves, the Ogallala Aquifer. The Ogallala Aquifer irrigates almost 30 percent of US croplands. This over-pumping has caused groundwater levels in the Ogallala to drop over 8 feet, with some counties in Texas seeing a drop of more than 15 feet in groundwater levels. Demands for agricultural products and sparse groundwater replenishment (in the form of rain) have led to a potential crisis in northwest Texas. More information regarding conservation efforts and water usage in the Ogallala Aquifer can be found by exploring the High Plains Water Districts' website.
This activity will introduce students to groundwater data collected from the USGS website and help them to prepare for the think-pair-share activity in the subsequent class session. An instructor's version can be downloaded here:
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Activity 6.1: Think-Pair-Share: Getting the Concepts (10 min)
Using pre-class activity results, students discuss the following concepts as an in-class, think-pair-share activity learn more about the think-pair-share method). Students may write their answers on index cards or on the board for further discussion as a class. This may be used as an assessment tool. Students should discuss the following questions in groups. To ensure students are focusing on the correct concepts for the think-pair-share activity, a summary of the key concepts for each question is provided in the
. These discussion questions are also found in the PowerPoint provided for activity 6.2.- What has happened to groundwater levels in the area investigated as time has progressed? What were the reasons for any changes?
- What sources other than agriculture could be contributing to the decline in groundwater? How do these sources use groundwater?
Activity 6.2: Groundwater Depletion (15 min)
- Groundwater Resources PowerPoint (PowerPoint 2007 (.pptx) 3MB Jun28 15)
Activity 6.3: Water Conservation Discussion (20 min)
The water conservation activity is embedded in the PowerPoint file from activity 6.2. Students will work in pairs with the each of the students reading a separate article. One student will read the Ogallala Initiative (Acrobat (PDF) 305kB Feb20 15), a fact sheet created by NRCS, designed to help landowners reduce water use. The second student will read the Ogallala Initiative Progress Report 2013 (Acrobat (PDF) 3.2MB Feb20 15). This document shows the status of the initiative, which has reduced water withdrawals from the Ogallala Aquifer by 489 billion gallons over 4 years. The Ogallala Aquifer Initiative (OAI) accounted for about 29 percent of this savings. Discussion questions are included in the PowerPoint.
Activity 6.4: Reflection (5 min)
For students to reflect on what they have learned in Unit 6, ask students to write on an index card one thing that they feel they have learned in this unit and one thing that still seems confusing, unclear, or incomplete. Collect the cards and use them to determine what aspects of the topic might need to be revisited in another class.
Teaching Notes and Tips
As a result of completing this unit, students should be able to comprehend the use, significance, and details of groundwater resources and their own connection to these resources via their water footprint—even if they do not live in the region of the Ogallala Aquifer. Instructors may expand upon the topics discussed in this unit to help students comprehend additional groundwater issues in other parts of the United States. Some topics that can be discussed and integrated into additional assignments are:
- Additional USGS well data for the Pre-Class Homework Assignment, if desired Additional USGS Well Data for Pre-Class Homework (Microsoft Word 2007 (.docx) 16.9MB Aug25 24).
- A further investigation of the Ogallala Aquifer using data from the USGS for a county with increased groundwater levels Data from Martin County, Texas (Microsoft Word 2007 (.docx) 11.5MB Aug25 24).
- Calculation of the water footprint of the food in a grocery bill, items on a restaurant receipt, or in their lunch. They can compare and combine these results with the water footprint data they collected in Unit 2 in which they calculated their daily water usage.
- Students can explore other conservation methods to save groundwater and give specific locations or communities that are implementing these techniques.
Use the provided rubric Assessment Rubric Unit 6 (Microsoft Word 2007 (.docx) 18kB Jun28 15) (or the PDF version (Acrobat (PDF) 56kB Jun28 15)) on the following take-home or in-class assessment questions to determine the level of comprehension:
- Describe the significance of the Ogallala Aquifer to US agriculture and explain why agricultural production is concentrated in this region of the United States.
- How might the groundwater of the Ogallala Aquifer be connected to the hydrological cycle and how is this relationship affected by overuse of the groundwater?
- What potential groups in society may be affected by overuse of the groundwater and why?
- You have been asked by a farmer in Amarillo, Texas, to explore the reasons why some of his wells are no longer producing water. Utilizing data from the USGS website, give a reason for the declining groundwater levels in the region and explain what steps could be taken to minimize the problem in the future.
References and Resources
- USGS groundwater information:
- US EPA groundwater information:
- Information from the Groundwater Foundation:
- New York Times article by Felicity Barringer, "Groundwater depletion detected from space" (2011):
- Resources concerning California's groundwater:
- USDA NRCS Ogallala Aquifer Initiative: