Restoring Hetch Hetchy: Myths and Facts

As California has grown, unique natural landscapes have been damaged. Yet Californians have shown a commitment to restore our magnificent natural heritage in places like Mono Lake and Lake Tahoe. Restoration of Hetch Hetchy Valley offers the opportunity to bring back another magnificent national treasure, while inspiring millions of people to become good stewards of the natural world.

Once depicted by famed naturalist John Muir as “one of Nature’s rarest and most precious mountain temples,” Yosemite’s neighboring Hetch Hetchy valley now lies submerged beneath 300 feet of water, dammed for nearly a century. With ingenuity and innovation, two things for which Californians are justly famous, we can restore the free-flowing Tuolumne River, and the forests and lush meadows of this glacially-carved jewel.

Those who do not support restoring Hetch Hetchy have mounted several myths or arguments in opposition to the restoration proposal. A closer look at the facts shows these arguments to be flawed. Will restoration take time and money? Yes. But, it is a safe, feasible and practical idea whose time has come. Restoration of Hetch Hetchy Valley will benefit countless generations.

MYTH #1: Removing Hetch Hetchy Reservoir would eliminate San Francisco’s water supply.

FACT: Hetch Hetchy Valley is not the source of San Francisco’s drinking water -- the Tuolumne River is the primary source. Hetch Hetchy Reservoir is only one of nine reservoirs that stores water from the Tuolumne River and local Bay Area watersheds. These supplies could be tapped directly without using Hetch Hetchy Valley as a reservoir, allowing for restoration while retaining more than 95% of the system’s output. Only an additional 5% of total supplies would be needed from other water projects and programs.

MYTH #2: San Francisco’s water quality will be diminished if Hetch Hetchy is restored.

FACT: The water drawn from Hetch Hetchy Reservoir is of high quality and has low vulnerability to many contaminants. However, San Francisco and its customers already blend this water with water from other reservoirs and other sources.

Approximately 15% of the San Francisco Public Utilities Commission’s (SFPUC) supplies are derived from local watersheds and are filtered, as are all Tuolumne River supplies that are stored in Bay Area reservoirs. In addition, many Bay Area water districts that buy water from San Francisco blend that water with supplies derived from the San Francisco Bay-Delta, local groundwater or other sources.

San Francisco’s Tuolumne water supply is unfiltered, but this exemption is rare among major municipal water systems and is not guaranteed into the future. With the addition of a filtration facility, a likely component of any restoration scenario, the prevalence of some key pathogens, such as cryptosporidium and giardia would be reduced, providing additional public health benefits. Not only will there be no degradation in quality, there may actually be an improvement in water quality.

MYTH #3: Restoring Hetch Hetchy Valley will put more pressure on the Delta ecosystem.

FACT: Water supply solutions proposed by Environmental Defense in Paradise Regained, as well as by others, have emphasized that high quality Tuolumne River water would continue to be the primary source of water supplied to the Bay Area. They involve changing only where some of the water is stored and the points from which it is diverted on the Tuolumne River. If Hetch Hetchy were restored there is no need to increase reliance on water from the San Francisco Bay-Delta ecosystem.

MYTH #4: Restoring Hetch Hetchy would jeopardize San Francisco’s control of its water.

FACT: San Francisco’s water rights on the Tuolumne River are protected by California law preceding the federal Raker Act of 1913 that authorized the O’Shaughnessy Dam in Yosemite National Park. Even if the valley were restored, San Francisco’s rights to water supplies from the Tuolumne River will not change.

MYTH #5: If San Francisco diverted water from Don Pedro Reservoir that would jeopardize the amount of water allotted to Turlock and Modesto in California’s Central Valley.

FACT: If water were no longer stored in Yosemite’s Hetch Hetchy Valley then more of the Tuolumne River’s flows would go directly into Don Pedro Reservoir, 35 miles outside of Yosemite National Park. This increased flow into the reservoir would ensure that the irrigation districts’ water supplies remain the same. If an intertie is constructed from Don Pedro to San Francisco’s pipeline system, allowing San Francisco to divert Tuolumne River water directly from Don Pedro Reservoir rather than from Yosemite National Park, a new negotiated agreement between San Francisco and the irrigation districts would be required.

MYTH #6 San Francisco has no storage rights at Don Pedro reservoir.

FACT: While the Turlock and Modesto Irrigation Districts own and manage Don Pedro Reservoir, San Francisco paid for half the cost of the reservoir’s construction in exchange for the right to “bank” up to 740,000 acre-feet of water in Don Pedro. (That’s more than twice the amount of water Hetch Hetchy Reservoir can hold.) The water is not currently diverted directly from Don Pedro into San Francisco’s pipelines, but the banking agreement allows San Francisco to divert water upstream of Don Pedro that would otherwise belong to Turlock and Modesto. As long as there is water in the bank, San Francisco is allowed to divert the Tuolumne River’s flow. San Francisco itself counts its supplies in Don Pedro as part of its overall storage, along with the supplies in its other eight reservoirs.

MYTH #7: Removing O’Shaughnessy Dam would eliminate some flood control on the Tuolumne River, amounting to increased flood risk to downstream communities.

FACT: Hetch Hetchy Reservoir is no longer operated to provide space for flood control. This function was moved downstream to Don Pedro Reservoir (which holds almost six times as much water) when it was completed in 1970. In its planning studies, the San Francisco Public Utilities Commission (SFPUC) provides 30,000 acre-feet in flood storage capacity at Hetch Hetchy Reservoir from October through March. Environmental Defense proposes to transfer this amount of extra flood protection to the SFPUC’s water bank in Don Pedro, and whenever possible, to divert any extra flows directly to water storage in the San Francisco Bay Area.

MYTH #8: We need more water storage in California, not less, and we are not developing enough new storage to meet anticipated population growth or to manage the earlier Sierra snowmelt that may result from global warming.

FACT: Contrary to popular belief, California continues to build water storage capacity, though today’s solutions are different from those of the dam-building era. Since 1990, California has developed more than 6,000,000 acre-feet of water storage (more than 17 times the storage volume of Hetch Hetchy) at six sites alone (see Environmental Defense’s Hetch Hetchy Water Supply in Context). Two of these, Los Vaqueros and Diamond Valley Reservoirs, are “off-stream” surface reservoirs, while the others are groundwater aquifers, which are recharged and actively managed to extend supplies in dry years.

Some communities have developed their own groundwater storage, and others have entered into banking contracts with agencies hundreds of miles away. For example, Santa Clara Valley Water District’s contract with Semitropic Water Storage District includes storage capacity of 350,000 acrefeet— almost identical to the volume of water in Hetc h Hetchy Valley.

Restoring Hetch Hetchy Valley will not reduce supply, but simply require that the water be stored outside Yosemite National Park. There are alternative ways to store the water storage provided by the Tuolumne River, but there is only one Hetch Hetchy Valley. While global warming and population growth may require the additional development of water and power, we should not abandon our commitment to protect and restore our most precious natural resources.

MYTH #9: Eliminating hydropower would compromise energy supplies and require the burning of fossil fuels which will be harmful to the environment.

FACT: Power is not generated on-site at O’Shaughnessy Dam; if the valley were restored a river would still run through it to hydropower facilities downstream. Restoration of Hetch Hetchy Valley does not imply the removal of any hydropower facility. Under a restoration scenario, flows from the Tuolumne River and releases from other system reservoirs could still generate 60-80% of the hydropower currently produced by San Francisco’s three generating facilities (Kirkwood, Moccasin and Holm Powerhouses). This amount of energy is more than sufficient to continue to power San Francisco’s public facilities, such as the airport, San Francisco General Hospital and city offices. The amount of hydropower currently generated in the system accounts on average for only 0.6% of California’s total generation. Environmental Defense proposes that replacement energy supplies could be largely made up through renewable resources, such as wind and solar, or by investments in energy efficiency, which could reduce dependence upon polluting fossil fuels.

MYTH #10: Elimination of Hetch Hetchy Reservoir could mandate the continued operation of dirty plants in the Hunters Point and Potrero Hill neighborhoods of San Francisco.

FACT: Hunter’s Point Power Plant was officially closed in May of 2006. The delay in decommissioning the Hunter’s Point Power Plant was due to concerns about the reliability of the transmission lines into the San Francisco peninsula, not the amount of power that would be lost if Hetch Hetchy is restored. A similar power plant in Potrero Hill is now under review, and once transmission upgrades and new backup capacity are completed, it too should be closed. Ed Smeloff, who managed power for the city of San Francisco, said it is “completely bogus” to assert that reduced hydropower production on the Tuolumne River would cause San Francisco’s dirty and obsolete power plants to continue operating.

MYTH #11 The total cost of restoration, including replacing the water and power supplies provided by O’Shaughnessy Dam, would range from $3 to $10 billion dollars.

FACT: The California Resources Agency's "Hetch Hetchy Restoration Study" released on July 19, 2006, estimated the costs of restoring Hetch Hetchy Valley to be $3 billion to $10 billion. The alternatives analyzed by the state, however, go far beyond the mere replacement of water and power, and therefore do not reflect the actual cost of restoration. Even the state’s low-end estimate would replace the necessary water supply by three times. The high-end of the state’s cost estimates includes a new reservoir and water treatment plant that are so expensive that no reasonable planner would consider them – comparable projects have been recently built at far lower costs. The state’s report, while finding that restoration is feasible, regrettably does not provide enough useful information for pursuing a costeffective plan to replace the water and power.

In our in-depth study of restoration, Paradise Regained, Environmental Defense developed with leading industry consultants an itemized estimate of the cost of replacing the water and power services provided by O’Shaughnessy Dam. Our estimates range from $500 million to $1.65 billion based upon which replacement strategies are utilized. Including the costs for dam removal, on the ground valley restoration and planning studies, along with an efficient plan that fully replaces water and power supplies, would result in a total cost that is well under $3 billion.

MYTH #12: A restored Hetch Hetchy Valley would be just one more tourist trap, beset with malls, parking lots and recreational vehicles.

FACT: Some of America’s national parks have been extensively developed and are perhaps at risk of being “loved to death.” Others are more carefully managed to maximize the protection of natural resources. Today extensive restoration is being undertaken in Yosemite National Park to better manage our natural resources and the nature experience. For example the recent restoration project at Yosemite Falls offers park visitors wider trails and a larger viewing area and also included removing dilapidated buildings and exhaust-belching buses and repairing crumbling trails. Environmental Defense proposes to make a restored Hetch Hetchy visitor- and family-friendly but with limited development to protect this national treasure.

MYTH #13: Hetch Hetchy provides excellent recreational and natural resource opportunities as a mountain lake.

FACT: While some hiking is allowed around the reservoir, no swimming or boating is allowed and there is no access to the expansive valley floor 300 feet below. The lake itself is not a haven for a diversity of wildlife. By restoring the valley, hundreds of acres of trails and wild areas would be opened up for the public to enjoy. In addition, unique meadow, river and forest habitats would be restored on the valley floor for Yosemite wildlife. By properly planning restoration and ongoing maintenance, it is possible manage Hetch Hetchy for both people and for wildlife.

MYTH #14: Hetch Hetchy Valley is not as grand as Yosemite Valley.

FACT: According to the U.S. Geological Survey, the Yosemite and Hetch Hetchy valleys are identical in length: 6.8 miles. Hetch Hetchy is narrower, however, and its area is about 1,730 acres, roughly onehalf of Yosemite Valley’s 3,510 acres. And it boasts several waterfalls and granite cliffs as wondrous as those in Yosemite Valley.

MYTH #15: Hetch Hetchy Valley won’t return to its natural state for hundreds of years.

FACT: The National Park Service has estimated that, within five years of draining Hetch Hetchy Valley and moving storage downstream, native grasses would reemerge on the valley floor and willows and alders would return to the banks of the Tuolumne River. Soon after habitats are restored, native wildlife will begin filtering back into the valley. It would take longer for ponderosa pines and oak woodlands to reach maturity and for lichen to grow anew on the canyon walls. But even during this time, millions of visitors would be drawn to the valley to witness and participate in the rebirth of a second Yosemite Valley. Environmental Defense believes restoring Yosemite’s twin will inspire future generations to protect and restore our most beloved natural places.

Posted: 08-Aug-2007; Updated: 08-Aug-2007