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Frequently Asked Questions

Where is Hetch Hetchy Valley?

Currently, Hetch Hetchy valley is flooded under 300 feet of water from the Tuolumne River. It is downstream from Tuolumne Meadows in Yosemite National Park and 15 miles north of Yosemite Valley.

The valley was dammed by the city of San Francisco in 1913 creating the Hetch Hetchy Reservoir. The dam is called O'Shaughnessy Dam.
Who is Restore Hetch Hetchy?

We are a grassroots, tax deductible nonprofit organization seeking to restore the valley to its natural splendor. We welcome members and supporters from throughout the world.
If we restore Hetch Hetchy where will San Francisco get its water?

The exact same place. The source of San Francisco's water is the Tuolumne River not Hetchy Hetchy Valley. The Tuolumne River will continue to supply the water once the valley is restored - it will simply be captured downstream and stored outside of Yosemite National Park.
Will San Francisco or local irrigation district water rights be harmed by dam removal?

No. San Francisco has very old water rights, and they will not be lost. San Francisco will still draw its water via the existing pipeline system with no loss of water rights. The Modesto and Turlock Irrigation District water rights are even more senior, and will likewise not be impaired.
How long will it take for the Valley to recover once the dam is removed?

In five years there would be vigorous growth along the Tuolumne River, with trees up to 10 feet high. In ten years the visitor would find a truly natural setting with native plants, grasses, wildflowers, and some relatively tall trees. Fifty years after restoration the Valley would be an established, relatively mature ecosystem much like Yosemite Valley.
How did the dam come to be built?

After the 1906 earthquake and fire, San Francisco claimed that Hetch Hetchy was the only good site to store water for the city and the San Francisco peninsula. Other equally appropriate dam sites outside Yosemite National Park were rejected. Teddy Roosevelt twice vetoed legislation to dam the Tuolumne but President Wilson signed the Raker Act in 1913, allowing the dam to be built.
Was there opposition to building the dam?

John Muir led the fight to preserve Hetch Hetchy Valley. Dozens of organizations and newspapers nationwide opposed the dam which ultimately resulted in the birth of the modern environmental movement.
How important is the dam in the context of California water supply?

Hetch Hetchy holds less than 1 percent of all stored water in California, and supplies less than one percent of California's water.

The San Francisco Public Utilities Commission (SFPUC) stores less than 20% of the water it manages in Hetch Hetchy reservoir. The remaining 80% is stored in 8 other reservoirs.

Since the water stored at Hetch Hetchy could easily be stored elsewhere in an enlarged Don Pedro Reservoir, at Calaveras Reservoir in the Bay Area, or underground), removal of the dam would have virtually no impact on the water supplies of the Bay Area.
Does the Bay Area need even more water from the Tuolumne River than it takes today to serve growth?

No. San Francisco has stated that with only modest conservation (7% beyond what is already expected), it will need no additional water through 2030. The other Tuolumne River water customers have projected a small growth in demand, but have estimated only a 6% savings from water conservation. Even a slightly more aggressive conservation program could eliminate the need for any additional Tuolumne River water.
How will the water supply be replaced?

San Francisco will continue to get its water from the hard-working Tuolumne River. Only the points of diversion and storage will change.

A wide variety of options are available to San Francisco to replace the water lost due to the removal of Hetch Hetchy Reservoir.

First, by diverting water from Cherry Creek into the existing Mountain Tunnel, and by diverting water from the Tuolumne River below Hetch Hetchy into the existing Canyon Tunnel, most of the water now stored in Hetch Hetchy can be brought to the Bay Area. There would be a small shortfall in some dry years.

The dry-year shortage can easily be made up by any one of the following options. Some could be combined if necessary.
1. Raising Don Pedro Reservoir, located on the Tuolumne River near Sonora. All the water from Hetch Hetchy could be stored in Don Pedro if it were raised less than 30 feet. This would inundate about a mile of the Tuolumne Wild and Scenic River, but restore more than 8 miles of the river in Hetch Hetchy Valley.
2. Supply water to San Francisco from the existing Don Pedro Reservoir, in conjunction with a program of coordinated use of groundwater by the irrigation districts (Modesto and Turlock) which also use water from the Tuolumne River.
3. Moderately increase water conservation and wastewater recycling programs in the Bay Area. San Francisco and other communities served by Hetch Hetchy water are far behind the rest of the state in recycling and conservation.
4. Store water in an enlarged Calaveras Reservoir in Alameda County, build an additional pipeline from the Tuolumne River to fill it during high flow periods, and divert water into the pipeline from Don Pedro Reservoir.
How important is the dam in the context of California energy supply?

Once the water diversion projects from Cherry Creek and the Tuolumne River (as described above) are complete, it will still be necessary to replace about 500 million kilowatt hours of electricity once O'Shaughnessy Dam is removed. This is less than two tenths of one percent (0.2%) of California's electricity supply.
How will the power be replaced?

A wide variety of energy replacement options are available. Each would easily replace the missing energy. They could also be combined.
1. Energy conservation in the Bay Area could quickly save the lost power. In addition, over 20 years, consumers would save more than twice the cost of the energy conservation program.
2. A new, low polluting natural gas combined cycle power plant would provide more than five times the amount of energy which needs to be replaced.
3. Solar photovoltaic cells and wind energy and could replace the lost energy, although at a higher cost than conservation or a conventional power plant.
What flood control benefits does the dam provide? How can these be replaced?

Hetch Hetchy Reservoir is not operated to provide flood control benefits. Sometimes, unintentionally, there is some space in Hetch Hetchy during a flood event, and some of the flood flows are captured.

If Don Pedro Reservoir is raised to replace Hetch Hetchy storage, a minor additional raise could provide reliable flood storage. This space could be left empty during the summer to prevent inundation of the Wild and Scenic Tuolumne River upstream, or it could be used to provide downstream fish flows.
Is there much silt in the Valley that will have to be removed as a result of 80 years of inundation?

No. In 1991 much of the Valley was exposed during the drought. Almost no silt was present, due to the granitic nature of the upstream watershed.
What will be done with the dam once it is removed?

The dam will be broken up on site, and moved by conveyor belt outside the park. There the pieces will be crushed, and turned into useful commercial aggregate. Pieces of the dam will also be sold as souvenirs.
What will be the effects on whitewater rafting and fishing downstream of the dam?

Without the dam, there will be some periods in the spring where flows are too high to raft. But a new flow release regime would in fact greatly extend the whitewater rafting and kayaking season, and increase recreational opportunities.

Minimum fish releases would remain in place. A more natural water flow cycle will occur below Hetch Hetchy Valley than occurs today. Furthermore, six miles of premium trout stream will be restored in Hetch Hetchy Valley.
What is CalFed, and will there be any effects on state water planning?

Cal Fed is a joint state-federal water planning program dealing with water supplies in California's Central Valley. San Francisco has long refused to release any of its water down the Tuolumne to the Sacramento - San Joaquin River Delta, even though every other water agency that diverts water away
from the Delta is involved in the effort to protect the Bay and Delta.
No water that presently goes to the Delta at critical times will be used to replace the Hetch Hetchy supply, so there will be no impact on the Delta, nor on the CalFed water planning process.
What will be the effect on San Francisco's current massive, multi-billion dollar water system renovation program?

None. Restore Hetch Hetchy supports the public safety and water quality elements of the water system renovation program (called the Capital Improvement Program). Some of the proposed elements of the program are particularly compatible with removal of the Hetch Hetchy Reservoir. Others do not affect it one way or the other. None are incompatible with removal of Hetch Hetchy Reservoir.
Who is in favor of removing the dam?

Many major conservation groups support a study of dam removal, and support removing the dam if feasible water and power supply replacements can be found. These include the National Wildlife Federation, Environmental Defense, Natural Resources Defense Council, and Sierra Club. Local Native Americans support a study of dam removal; they are particularly concerned that their ancient sites be protected once the dam is removed.
San Francisco does not filter its water. Will the new water supplies need filtration?

Yes. In fact, San Francisco would benefit from filtering its water supply today. Every other major water supply in California (and almost everywhere in the United States) is filtered today. Lack of filtration increases the number of infectious giardia and cryptosporidium organisms in the water supply, a threat to everyone, especially those with compromised immune systems. San Francisco advises people with compromised immune systems to discuss drinking city water with their physician, and to consider boiling the water before drinking it!
What will be the impact on water quality of removing the dam?

With filtration, San Francisco's water supply will be of higher quality than it is today.
What studies have been done on the feasibility of removing the dam and replacing the water and power supplies?

In 1987, President Reagan's Interior Secretary Donald Hodel commissioned a study by the U.S. Bureau of Reclamation engineers that described ways to replace water storage and electricity generation without the O'Shaughnessy Dam. In 2003, UC Davis grad student Sarah Null and her advisor, Dr. Jay Lund, completed a study of ways to restore Hetch Hetchy and address the water storage and power concerns of various stakeholders with use of the Don Pedro Reservoir.

In September, 2004, Environmental Defense released a study that shows how the Don Pedro Reservoir could be used to replace much of the storage lost at Hetch Hetchy. Additional storage at Calaveras Reservoir could replace the rest.
How much will a restoration program cost?

The entire program of dam removal, valley restoration, and water and power supply replacement is estimated to cost between $1-3 billion.
Who will pay for the program?

There are many possible public and private funding sources. State bond acts, federal appropriations, and revenue from the entrance fees at Yosemite, all could be used.

Because Hetch Hetchy Valley is in Yosemite National Park, all Americans can be called upon to participate in funding costs of restoration. The entire $500 million cost of restoring the Statue of Liberty was paid for by private donations.

With these funding sources, San Francisco water and power users would not have to pay more to restore the Valley than other California water and power users.
What needs to happen to remove the dam?

Since funding is needed, some Congressional action will be required. Similar funding will have to be provided on the state level. The San Francisco Board of Supervisors, and perhaps the voters, may be asked to approve the removal of the dam and the installation of new replacement water and power supplies.