Whose Water Is It? 


Teacher Notes

"Should San Franciscoans curtail their Saturday night bath to make sure that John Muir and his nature-loving friends can go for a pleasant walk in the woods? We think not."

S.F. Chronicle

The year is 1908. You live in San Francisco. It was just two years ago that the city was shaken for a full two minutes by a very powerful earthquake. Because of that natural disaster, and the fires that were caused by the earthquake, the people of San Francisco realize they will need more water for the city to be safe.

San Franciso is situated in a dry climatic belt in the summer, and receives very little rain from May until October. During the months of October through the following May the rains are very heavy and frequent. All of the rain falls in only eight months each year.

As a result, the people of San Francisco have decided they need to store large volumes of water. When San Francisco became a city, the original city rules of 1900 said the city should have its own water supplies and facilities.

The city of San Francisco has been looking for sources of water. One way to collect water for the city is to build a dam which will create a resevoir. The city looked carefully at the entire region from which it would be possible to obtain water. Finally it was decided that the Tuolumne River would be a good source. The Tuolumne River is 120 miles east of San Francisco, and drains an area of 1,501 square miles on the western slope of the Sierra Nevada mountain range.

The area selected for a resevoir is in the area set aside in 1890 as Yosemite National Park. There are two large drainage areas in the park. One is the drainage area of the Merced River. The Merced River flows through the southern portion of the park and passes through the famous Yosemite Valley. The other drainage area is north of Yosemite Valley, about a day's journey by horse. This drainage area contains the Hetch Hetchy Valley and the Tuolumne River. This is an area where nobody could live. People can travel there only three or four months during the summer. In other months the roads and trails are covered with snow and ice.

Since the valley is in a national park, permission to build a dam must be given by the Federal Government. On December 16, 1908, a hearing will be held in Washington. The committee on the Public Lands of the House of Representatives will decide whether or not the people of San Francisco can build a dam across the Tuolumne River. If the dam is built, the Hetch Hetchy Valley will be flooded and access to its natural resource will be lost.

The Task

In this activity you will be exploring water issues in California since 1900. You will be researching the controversy surrounding the damming of the Hetch Hetchy Valley in Yosemite National Park. You will also look at Internet and other resources that show where Californians get their water and what they use it for.

After looking at the resources, your task will be to, design, and present a poster about the damming of the Hetch Hetchy Valley. Along with your poster, you will write a letter to the committee on public lands of the House of Representatives letting the committee know of your position.

You will be part of a group representing either the people of the city of San Francisco who need water, or the conservationists who were against the dam being built. You must be able to explain the point of view presented on your poster. You and your group must gather the information needed to convince the committee that your position is the correct one.

As an extended activity, you and your teacher may decide to hold a mock hearing before the 'committee on public lands of the House of Representatives'. This committee could be a group of adults, such as your teacher, principal, and some parents. As students you will represent either the people of San Francisco who wanted to build the dam, or the preservationists who did not want the dam to be built. One of the adults can be the chairman and call on the students who wish to express their point of view.

The Process

You will need to divide the class up into groups of four students. Each student in the group will be responsible for answering one of the questions in Step 1, Step 2, and Step 3.

Step 1 - Before you create your poster and write your letter, you first needto answer the following questions.

1. Why did the city of San Francisco need more water?
2. Where did the city of San Francisco get their water from at the time of the Great San Francisco Earthquake of 1906?
3. What was the argument for building the dam?
4. What was the argument against building the dam?

Step 2 - Once you have answered the first set of questions, you are ready to consider the following questions.

1. Do you think San Francisco should have dammed the Hetch Hetchy Valley? Why or why not?
2. What other options did San Francisco have to get water?
3. What has been the long term impact of damming the Hetch Hetchy Valley?
4. What would be the impact of not damming Hetch Hetchy?

Step 3 - Now you are ready to consider the final set of questions.

1. Where does the water come from that you use at home and school?
2. What are the different uses of water in California?
3. What are water rights?
4. Who manages California's water resources?

Step 4 - After you have gathered all the information needed to answer the questions, design a poster communicating your group's point of view.

Your poster should state the reason for your group's position.
Your poster should explain why your point of view is correct.
Your poster should contain both text and pictures.

Step 5 - Write a letter to the committee on public lands telling them whether or not you think the Hetch Hetchy Valley should be dammed and explain your answer. Your letter should contain the five W's:


These resources are good starting places. Remember, the Internet is not always the best place to do your research. You'll also want to use your library as a source of information.

Examples of other resources:

Learning Advice

You will need to know how to print and save text/graphics from web pages. Have a pencil and paper with you when you are on the web so you can write notes and web page addresses. Make sure everyone in your group has a responsibility. Each person in your group should be answering one question from each of the three steps. Remember, we all have different talents and abilities which make us valuable in a group. Take time to discover everyone's strong points so each of you are able to make the greatest contribution to the group.


You will be evaluated based on three areas:

the poster
the letter
the oral presentation of your poster

At the beginning of the activity, the class and your teacher should decide what makes a good poster, presentation, and letter. Using the ideas from the discussion, your teacher will create a rubric for scoring your work.


Deciding to build a dam is something that requires a lot of thought. There are many things to be considered when making a decision that will affect so many people. Now that you have come to the end of the activity, it is time to answer these questions. Write down your answers for homework and be prepared to participate in a class discussion.


Name: David Hoffman
School/District: Madera County Office of Education
E-mail: dhoffman@maderacoe.k12.ca.us
CHSSP-SCORE Technology Academy 1997
Reviewed for accuracy by Dr. Al Rocca, Simpson College

 Technical questions on the website to: hoa_nguyen@sbcss.k12.ca.us

Last Revised: Thursday, April 6, 2006