# Hands-on Activity: Dam Pass or Fail

### Summary

Students conduct Internet research to investigate the purpose and current functioning status of some of the largest dams throughout the world. They investigate the success or failure of eight dams and complete a worksheet. While researching the dams, they also gain an understanding of the scale of these structures by recording and comparing their reservoir capacities. Students come to understand that dams, like all engineered structures, have a finite lifespan and require ongoing maintenance and evaluation for their usefulness.

### Engineering Connection

All engineered structures have a limited lifespan and require maintenance to remain useful and safe. Engineers deepen their knowledge of a topic and learn from past examples (including failures) by investigating existing and past designs. Understanding the importance of continuus maintenance of engineered structures such as dams is helped by researching real-life examples.

### Educational Standards

•   Common Core State Standards for Mathematics: Math
•   International Technology and Engineering Educators Association: Technology

### Pre-Req Knowledge

Basic Internet navigational skills. Familiarity with the four basic types of dams (embankment, arch, gravity, buttress) as described in lesson 2, Water and Dams in Today's World of the Dams unit, is helpful.

### Learning Objectives

After this activity, students should be able to:
• Compare dam reservoir volumes by ranking.
• Know that dams have a finite lifespan.
• Know that engineers are responsible for the safety and reliability of dams.
• Name at least five notable dams.

### Materials List

Each student needs:

### Introduction/Motivation

In today's world, dam failure or removal is a real possibility. Dams that were built 50 to 100 years ago are aging and failure can happen for any number of reasons. Let's brainstorm: For what reasons might a dam fail? (Take suggestions from students.) A dam could fail for all sorts of reasons, including inadequate inspection, faulty design, earthquakes, or lack of maintenance.
In recent years, more and more dams have been removed on purpose. For what reason would a dam be removed? Well, sometimes a dam is in such bad condition that it cannot be repaired and is unsafe, so it is removed to keep it from being a hazard. But more often, dams are removed for environmental reasons or because they no longer serve a useful (needed) purpose. Who can tell me what environmental reasons might cause people to want to remove a dam? (Possible answers: To improve river habitat, restore fish migration routes.) The Sierra Club is concerned about Splash Engineering's designing the two dams for Thirsty County because of environmental reasons. Who can guess what these reasons might be? (Take suggestions from students.) Some dams, such as the Edwards Dam in Maine, were removed because they caused more environmental harm than societal good. Communities must continually weigh the advantages and disadvantages of having dams on their local rivers. If a community concludes that the disadvantages outweigh the advantages, they might remove the dam. In fact, nearly 800 dams have been removed in the last 100 years (of the ~80,000 dams in the US).
How do we know the condition of our dams? Who is responsible for their inspection? Their maintenance? Their removal? Inspecting, and overseeing maintenance and the careful process of removal of dams are all responsibilities of engineers.
In this activity, you, the engineers of Splash Engineering, are going to use the Internet to research some existing dams so that we can learn about what works and what does not. You want your designs for Thirsty County to succeed. You want your designs to not fail in the same ways that previous dams around the world have failed. Learning about failed dams helps engineers avoid making similar design mistakes for new dams. Successful engineers study past designs to learn from them.
Raise your hand if you have ever done research on the Internet before. If you have not done much research on the Internet, you can think of the Internet like a big library that is easy to use because you don't have to lift heavy books off the shelf! Let's get started.

### Vocabulary/Definitions

 coffer dam: A temporary dam used to control a river or reservoir while constructing or removing the primary dam. lifespan: The length of time something, such as a dam, is expected to last. maintenance: Any work needed to keep an object or machine functional. spillway: Part of a dam that can release surplus flow without causing damage to the dam.

### Procedure

Before the Activity

With the Students

1. Get students set up and oriented on the computers.
2. Make sure that students find the correct website: http://www.pbs.org/wgbh/buildingbig/dam/
3. Hand out the worksheets and have students fill them out while researching the dams.
4. For students who finish early, direct them to continue their research by answering bonus question #3.
5. Conclude with a class discussion to review students' activity worksheet data and reservoir capacity rankings. What were you able to find on the Internet? (See additional discussion questions in the Assessment section.)
6. Have students who completed the bonus question share with the class what they learned about actual cases of dam removals around the country.

### Troubleshooting Tips

Some students may not be familiar with Internet research, Internet browser applications or even computers. As necessary, provide appropriate tutorials in a prior class to prepare students for this activity.

### Assessment

Pre-Activity Assessment

Review on the Board: Review the four types of dams by drawing them on the board (see Lesson 2). Ask students to name the four different dam types (embankment, arch, gravity, buttress) and what they are made of (embankment dams are made from earth and rock; the rest are made of concrete.)

Activity Embedded Assessment

Activity Worksheet: Have students individually complete the Does the Dam Pass or Fail? Worksheet while completing their Internet research Review their answers to gauge their mastery of the subject.

Post-Activity Assessment

Class Discussion: As a class, discuss the worksheet results. Ask the students:
1. Did everyone rank the dams in the same order? (Compare students' answers.)
2. Did any of these dams fail? (South Fork Dam and Folsom Dam) Why? (Collapsed due to debris-clogged spillway preventing controlled water release during rainstorm; broken spillway gate due to design flaw.) What can we learn from these failures? (Perform regular dam inspection and maintenance; improve the design of dams with roll-up spillway doors.)
3. Were any of these dams removed? (Edwards Dam) Why? (Blocked fish from reaching spawning grounds upstream; supplied very little hydroelectric power compared to other Maine sources of electricity.) What happened to the river in the years after the dam was removed? (Fish and healthy ecosystem returned to Kennebec River, sunken logs are being salvaged and recycled, many other dams have since been removed for same reasons.)
4. What other observations did you make when learning about all these dams?
5. What new questions do you have?
6. By looking at the data you collected how old are these dams? What are the lifespans of the dams we have researched? (Edwards Dam was 162 years old when it was removed; South Fork Dam was 37 years old when it collapsed; others 18 to 70+ years old and still operating.)
7. Who is responsible for the safety and reliability of dams? (Answer: Engineers)
8. Tell me which dam was of most interest to you and why?

### Activity Extensions

Ask students to make a bar graph detailing the purposes of the eight researched dams. The graph should show how many dams are used for hydropower, flood control, irrigation, navigation, and recreation (and any other purposes discovered through the research).
Assign further research into dams being removed for environmental reasons. In Oregon, dam removal has been completed or proposed in order to restore salmon passage to natural conditions. How did the river adjust to the resulting sediment left by the removed dam? Assign students to research the pro and con arguments of actual cases, such as the Marmot Dam on the Sandy River, the Savage Rapids Dam on the Rogue River, and four dams on the Klamath River. Example resources: http://or.water.usgs.gov , http://www.usbr.gov, http://www.seattletimes.com/outdoors/oregon-to-fund-klamath-river-dams-removal/.
Assign another direction for research: Some people characterize dams as "19th century solutions to 21st century problems." So, what is the future of dams? Are dams needed anymore? What are alternatives to dams? Why might dams not work for the 21st century? See the California's Statewide River Conservation Organization's Friends of the River website at http://www.friendsoftheriver.org – Why Dams Don't Work" and http://www.friendsoftheriver.org - Alternatives to Dams.

### Activity Scaling

• For lower grades, have students work in pairs to complete the activity worksheet.
• For upper grades, have students research other dam failures (such as the Teton Dam) or dam removals on the Internet. Suggested search terms: "dam failure" and "dam removal." Or, assign students to complete the projects described in the Activity Extensions section.

What happens when a dam collapses? Can engineers model the collapsing of a dam? What is the link between predicting earthquakes and crumpling a piece of paper? See the many resources available at Cracking Dams, a SimScience website that provides lesson plans, teacher guides, case studies, computer simulations, movies, scenarios, quizzes and glossaries at http://simscience.org/cracks/.
Resources to investigate dam failures:
• List of Dam Failures, Wikipedia, The Free Encyclopedia, http://en.wikipedia.org/w/index.php?title=Dam_failure&oldid=319455970.
• Historic Dam Failures in the US, ASDSO, http://www.damsafety.org/news/?p=94bdfdd0-633a-4fa2-bc39-0083c58d14ba.
• Examples of recent dam failures and their implications, Cracking Dams, http://www.simscience.org/cracks/intermediate/failures.html.
Resources to investigate dam removals:
• Dams Slated for Removal in 1999-2008, American Rivers, http://act.americanrivers.org/site/DocServer/DAMS_SLATED_FOR_REMOVAL_IN_2008.pdf?docID=8501 and http://www.sejarchive.org/pub/Dam-Removal-Summary1999-2007.pdf.
• Clearinghouse for Dam Removal Information (search the database), http://www.lib.berkeley.edu/WRCA/CDRI/.
• Major dam removal projects and dams that have been discussed for removal, Dam Removal, http://en.wikipedia.org/w/index.php?title=Dam_removal&oldid=317134283.
• Fort Halifax Dam removed to open fish passage, Natural Resources Council of Maine, http://www.nrcm.org/fort_halifax_removal.asp.
• The Long Road to a 2009 Dam Removal, WaterWatch, Oregon, http://www.waterwatch.org/programs/freeing-the-rogue-river/savage-rapids-dam-removal.

### References

Building Big: All About Dams. Public Broadcasting System Online. 2000-01. WGBH Educational Foundation. Accessed October 14, 2009. http://www.pbs.org/wgbh/buildingbig/dam/index.html

Dams and Dam Removal. 2001-07. Department of Natural Resources, Michigan. Accessed October 14, 2009. http://www.michigan.gov/dnr/0,1607,7-153-10364_27415---,00.html

Ladd, Chris. Published July 23, 2009. Dam It All. Good.Is Magazine. Accessed October 14, 2009. (Good recap article on the state of dams, present and future, in the US, including failures, removals and river recovery.) http://www.good.is/post/dam-it-all/

Nearly 800 Dams Already Removed across US. Posted November 26, 2008. The Society of Environmental Journalists, Jenkintown, PA. Accessed October 14, 2009. http://www.sej.org/publications/tipsheet/nearly-800-dams-already-removed-across-us

### Contributors

Jeff Lyng, Kristin Field, Denali Lander, Megan Podlogar, Denise W. Carlson