Unit 2: Water Footprints
Unit 2 opens a window into water accounting and reveals intensive water use that few people think about. How much water goes into common commodities? Have you considered how much water it takes to support our modern American lifestyle and agricultural trade? Water that is embedded in products and services is called virtual water. Looking at the world through the lens of virtual water provides a watery focus to thorny discussions about water such as: the pros and cons of globalization and long distance trade; self sufficiency vs. reliance on other nations; ecosystem impacts of exports; and the impacts of relatively cheap imports on indigenous farming. Unit 2 also introduces the concept of a water footprint. A water footprint represents a calculation of the volume of water needed for the production of goods and services consumed by an individual or country. In this unit students will calculate their individual footprints and analyze how the water footprints of countries vary dramatically in terms of gross volumes and their components. As a result of these activities, students will learn of vast disparities in water access and application. They will also be challenged to consider mechanisms or policies that could foster greater equity in water footprints.
Unit 2 is designed to help students advance in achievement of both Module Learning Goal 1 and Module Learning Goal 2:
- Module Learning Goal 1: Students will explain how fresh water availability and management practices pose threats to ecosystem integrity, human well-being, security, and agricultural production.
- Module Learning Goal 2: Students will explain what goes into the calculation of virtual water amounts and water footprints and the application of these concepts.
The unit also has the following more specific learning objectives.
Upon completion of the unit, students should be able to:
- Explain the concept of virtual water and how the amounts of water embedded in commodities varies by commodity and region of production.
- Evaluate the pros and cons of virtual water trade.
- Explain how water footprints are calculated and differentiate between internal and external water footprints.
- Differentiate between green, blue and grey water in water footprint analysis.
- Interpret individual and national water footprint data and explain how water footprints relate to water scarcity, water degradation, and water-related equity and sustainability.
- Demonstrate facility in working with student partners in equitable and inclusive collaboration.
- Demonstrate improved ability to analyze and evaluate quantitative information.
- Synthesize interdisciplinary information in a holistic analysis of water-related problems.
Context for Use
This is the second unit of a module on water sustainability, particularly as it relates to agriculture. This unit focuses on how we can account for water use and trade at individual, regional, national, and global scales via the virtual water concept and water footprinting. As virtual water trade and water footprints are dominated by agricultural production, this unit provides a natural segue between the concepts of water (un)sustainability covered in the previous unit and irrigation practices covered in the following units. Like Unit 1, this unit is very interdisciplinary in nature. It requires students to fuse geoscience and economic based perspectives in a more holistic analysis. Instructors should point this out to students and periodically check in on the challenge students are experiencing in working across disciplines.
Class Size: This can be adapted for a variety of class sizes.
Class Format: In activity 2.1b, students collaborate in pairs to answer a series of questions in a worksheet focused on the issues and data associated with the concepts of virtual water. Activity 2.1c has students brainstorming in small groups, then participating individually in a whole-class debate on the pros and cons of virtual water trade. In Activity 2.2b, students collaborate in small groups (3-5 students each) to answer a series of questions in a worksheet on water footprinting.
Time Required: The in-class activities of this unit are designed to take three 1-hour class periods.
Special Equipment: The instructor must supply the worksheets provided below for activities 2.1b and 2.2b. Unit 2.1 recommends that instructors foster online discussions of readings prior to the class periods for that unit. If instructors do not have access to online teaching platforms like Blackboard or Canvas, they could try out free online chat services like Google Hangouts.
Skills or concepts that students should have already mastered before encountering the activities: Before each in-class activity, each student will need to do the assigned readings and participate in the online discussions. Unit 2.2 requires students to complete a homework assignment in order to participate in the in-class activity of the unit. These preparatory activities will give them the background necessary to analyze and critique virtual water and water footprint data and controversies.
This unit can stand alone, if desired, and is most appropriate for upper-level undergraduate students in any major. It is designed to foster global learning and an appreciation of a systems approach to evaluating water problems. This unit is particularly useful for exposing Earth Science majors to the cultural and economic geography of water allocation and use.
Description and Teaching Materials
This unit is presented in 2 sub-units. Sub-unit 2.1 is centered on virtual water. Sub-unit 2.2 is centered on water footprints. This unit includes a class debate and a homework assignment to be submitted for a grade. These two sub-units are designed to take three class periods, each lasting one hour.
Unit 2.1 - Virtual Water (90-100 minutes stretched over two 1 hour class periods)
The activities in this sub-unit develop an understanding of the concept of virtual water and provide opportunities for the development of critical thinking and communication skills. Students tend to be shocked when they learn how much water goes into common commodities, such as pizza, burgers, t-shirts and shoes. Looking at the world through the lens of virtual water also provides a watery focus to thorny discussions of the pros and cons of globalization and long distance trade, self sufficiency vs. reliance on other nations, ecosystem impacts of exports, and the impacts to indigenous people and their farms introduced by importing cheap mass-produced food.
Activity 2.1a - Homework: Reading Assignment and Online Discussion on Virtual Water
This activity is to be completed as homework in advance of the class period. Suggested readings and discussion prompts are found in the following guidance document, as are the specific learning goals. Instructors are encouraged to offer a small amount of points for satisfactory participation in the online discussion.
- Instructor Guidance for Activity 2.1a: Reading Assignment and Online Discussionfor Virtual Water (Microsoft Word 2007 (.docx) 23kB Aug21 23)
Activity 2.1b - Interactive Lecture and Student Handout Analysis on Virtual Water Statistics (40 minutes)
This activity engages student learning on the concept and statistics of virtual water via a PowerPoint slide presentation and a handout with questions for students to answer. Students working in pairs will analyze the virtual water quantities in several commodities, consider how that varies from region to region, and calculate how much virtual water resides in their t-shirt and shoe collection. The end of the slide presentation sets up the Virtual Water debate that takes place as Activity 2.1c. The first document below provides guidance for the instructor in running Activity 2.1b. It includes the virtual water handout with questions for students to answer, along with guidance for the instructor on the context of the activity and the learning objectives for the activity. The second document is the handout/worksheet to be distributed to the students for Activity 2.1b. The third file is the PowerPoint presentation for Activity 2.1b.
- Instructor Guidance for Activity 2.1b: Virtual Water Worksheet (Microsoft Word 2007 (.docx) 352kB Jan23 17)
- Student handout for Activity 2.1b: Virtual Water Worksheet (Microsoft Word 2007 (.docx) 352kB Feb2 17)
- Slides for Activity 2.1b: Pair Analysis on Virtual Water Statistics (PowerPoint 2007 (.pptx) 616kB Jan23 17)
Activity 2.1c - Class Debate: Should the World Rely More on Virtual Water Trade? (60 minutes - 20 minutes at the end of the first class session and 40 minutes for the next class session)
There are serious pros and cons to the virtual water trade and the trend for ever greater reliance on it. How one weighs the pros and cons relates to the ideology of sustainability. This is probably the most inherently interdisciplinary activity of the module, unfolding at the intersection of geoscience, economics, ethics, and politics. Instructors are encouraged to highlight this complexity and point out connections between debate arguments and personal value sets.
What follows is the guidance document to run the class debate on virtual water. It is recommended that the last 15-20 minutes of the first class day of this unit be used by students in groups to prepare for the Virtual Water debate. The actual debate (40 min) is suggested to take place during the first half of the following class period. PowerPoint slides associated with the Virtual Water debate are found below the guidance document for Activity 2.1b. Note that Activity 2.2a (Reading Assignment and Water Footprint Homework Assignment) should take place between the first and second class day of this unit.
- Instructor Guidance for Activity 2.1c: Virtual Water Debate (Microsoft Word 2007 (.docx) 24kB Jan23 17)
- Slides for Activity 2.1c: Virtual Water Debate (PowerPoint 173kB Jan23 17)
Unit 2.2 - Water Footprints (80 minutes stretched over 2 class periods)
In lieu of a 20-minute PowerPoint overview, the activities of this sub-unit are designed to develop a better understanding of the calculation and application of water footprints through critical thinking, numeracy, and communication skills. It impresses upon students the great variability of national water footprints per person and how the water footprint of many regions exceeds the natural supply within their basin. Student analysis of water footprint data provides the basis for a discussion on whether water footprints should be more tightly controlled for the sake of international equity, ecosystem requirements, and long-term water sustainability.
Activity 2.2a - Reading Assignment and Water Footprint Homework Assignment
This activity is to be completed as homework in advance of the class on water footprints as well as Activity 2.1c. The first file below contains a guidance document for Activity 2.2a, with context and learning goals, suggested readings and the homework assignment. The next document contains the student homework assignment: to calculate their individual water footprints. 10 points can be awarded to students for satisfactory completion of the assignment.
- Instructor Guidance for Activity 2.2a: Reading and Homework Assignment on Water Footprints (Microsoft Word 2007 (.docx) 20kB Aug21 23)
- Student Handout for Activity 2.2a: Reading and Homework Assignment on Water Footprints (Microsoft Word 2007 (.docx) 21kB Aug21 23)
Activity 2.2b - Group Work: Analysis of Individual Water Footprints and Footprints of Nations (80 minutes stretched over 2 class periods - 20 minutes on day 2 of the unit, 60 minutes on day 3)
This activity will extend over 2 class periods. After the virtual water debate (Activity 2.1c), students will work in small groups to share their individual water footprint results for 20 minutes. During the second class period, students will work in small groups to analyze various water footprint statistics and figures. Students apply this information to discuss water footprint regulation, whether or not there should be a maximum allowable water footprint amount per person or nation. The first document below provides detailed guidance for the instructor on how to run Activity 2.2b, with context and learning goals. The second document is the student worksheet.
- Instructor Guidance for Activity 2.2b: Analysis of Water Footprints (Microsoft Word 2007 (.docx) 308kB Feb24 17)
- Student Handout for Activity 2.2b: Analysis of Water Footprints (Microsoft Word 2007 (.docx) 305kB Feb24 17)
Power Point presentation on Water Footprints for use in class.
- Slides for Activity 2.2b: Water Footprints (PowerPoint 2.7MB Feb23 17)
Teaching Notes and Tips
Detailed teaching guidance is provided in the various downloadable documents in the section above. The two sub-units should take 3 one-hour class days, though an instructor can easily stretch the topics and material out to take more class time. The primary pedagogies involved in this unit include class discussion, a class debate, and both group and pair analysis of quantitative information and texts.
Instructors can assess how well each student understands the concept of virtual water and the pros and cons associated with virtual water trade by reviewing (and challenging) their posts in the online discussion for this unit. Instructors can further assess the depth of class thinking on the pros and cons associated with virtual water trade by the quality of the debate they do in Activity 2.1d. Student achievement of the learning goals associated with the water footprints will be assessed via an individual homework assignment as well as by group responses to an in-class worksheet.
The instructor will be able to assess whether students are making advances in the learning objectives for this unit, as well as meeting the more content-specific objectives listed in the summary at the top of this page, by student participation in the group work and the online and class discussions.
As an optional summative assessment of what students have learned by participation in Units 1 and 2, you can have them write an essay as a homework assignment following Day 3 of Unit 2. The prompt for the reflective essay assignment is provided below.
Sustainability in the Context of Water Essay Assignment (Microsoft Word 2007 (.docx) 17kB Jan23 17)
References and Resources
This unit is built around the following articles and online resources. For the 3-day unit, students are asked to read 6 of the articles, as well as visit the water footprint calculator web sites.
Aldaya, M.M. and Hoekstra, A.Y. (2010). The Water Needed for Italians to Eat Pasta and Pizza. Agricultural Systems, 103: 351–360.
Chapagain, A.K., Hoekstra, A.Y. and Mekonnen, M. (2007). Your Water Footprint - The Quick Calculator. University of Twente.
Chapagain, A.K., Hoekstra, A.Y. and Mekonnen, M. (2007). Your Water Footprint - Extended Calculator. University of Twente.
Chapagain, A.G., Hoekstra, A.Y. and Savenije, HHG (2006). Water Saving Through International Trade in Agricultural Products. Hydrol. Earth Syst. Sci., 10: 455–468.
Hoekstra, A.Y. (2011). The Global Dimension of Water Governance: Why the River Basin Approach Is No Longer Sufficient and Why Cooperative Action at Global Level Is Needed. Water, 3: 21-46.
Hoekstra, A.Y. (2012). The Hidden Water Resource Use Behind Meat and Dairy. Animal Frontiers, 2(2): 3-8.
Hoekstra, A.Y. and Chapagain, A.K. (2006). Water Footprint of Nations: Water Use by People as a Function of their Consumption Pattern. Water Resource Management, 21: 35-48.
Hoekstra, A.Y. and Mekonnen, M.M. (2012). The Water Footprint of Humanity. Proceedings of the National Academy of Sciences of the United States of America, 109(9): 3232-3237.
Hoekstra, A.Y., Mekonnen, M.M., Chapagain, A.K., Mathews, R.E., and Richter, B.D. (2012). Global Monthly Water Scarcity: Blue Water Footprints versus Blue Water Availability. PLoS ONE, 7(2): e32688.
Mekonnen, M.M. and Hoekstra, A.Y. (2010). The Green, Blue and Grey Water Footprint of Farm Animals and Animal Products. Value of Water Research Report Series No. 48, UNESCO-IHE, Delft, the Netherlands.
Mekonnen, M.M. and Hoekstra, A.Y. (2011). National Water Footprint Accounts: The Green, Blue and Grey Water Footprint of Production and Consumption. Value of Water Research Report Series No. 50, UNESCO-IHE, Delft, the Netherlands.
Smakhtin, V., Revenga, C., Doll, P., and Tharme, R. (2003). Giving Nature Its Share: Reserving Water for Ecosystems, in Putting the Water Requirements of Freshwater Ecosystems into the Global Picture of Water Resources Assessment. Draft paper presented at the 3rd World Water Forum, Kyoto, Japan, March 18th, 2003.
Wikipedia (2014). Virtual Water.
World Water Council (2003). Session on Virtual Water: Water Trade and Geopolitics.