Tourists overflow Yosemite Park. Hodel's earthshaking solution: drain Hetch Hetchy reservoir

Anticipation builds as the car emerges from the dim mountain tunnel and sweeps around an S-curve. Suddenly, there it is - a breathtaking vista of the world-famous Yosemite Valley, its sheer granite walls backlit by a late-summer sun. But down on the valley floor an impressive sight of another kind often greets visitors - a line of cars stretching as far as the eye can see. In Yosemite National Park everything is monumental in scale, and traffic jams are no exception.

The National Park Service has struggled for years to find ways to alleviate congestion in Yosemite Valley, the glacially-carved trough that attracts 80 percent of all visitors to Yosemite. Park Service officials want to ban cars from the valley floor, but they acknowledge that goal is decades away. Meanwhile, they've added parking spaces, introduced shuttle buses, and trained a special ``traffic strike force,'' which is at the ready this weekend for summer's Labor Day finale.

On a grander scale, United States Secretary of the Interior Donald Hodel last month offered a startling idea for reducing overcrowding in Yosemite Valley. His idea, which environmentalists say came like a bolt out of the blue, is to restore Hetch Hetchy, the park's ``other'' glacial valley 26 miles to the north.

The floor of Hetch Hetchy Valley is under 250 feet of water. In fact, since O'Shaughnessy Dam was completed in 1919, the valley has been called Hetch Hetchy Reservoir, providing water and electricity to the San Francisco metropolis and other California communities.

Naturalist John Muir led the fight to stop Congress from granting San Francisco the rights to water from the Tuolumne River. He compared damming Hetch Hetchy with flooding the ``people's cathedrals and churches, for no holier temple has ever been consecrated by the heart of man.''

California officials and environmentalists were agog over Secretary Hodel's idea of draining Hetch Hetchy - but for different reasons. San Francisco Mayor Dianne Feinstein immediately denounced the proposition, noting it would deprive the city of water, electricity, and about $30 million in revenue it collects annually from selling Hetch Hetchy power to other communities. Others cite the billions of dollars it would cost to tear down the dam, compensate San Francisco for loss of its assets, find new sources of water and power for the city, and reclaim the valley.

Most environmental groups, on the other hand, applaud the idea. ``That dam should never have been built in Yosemite National Park in the first place, and it's bound to come out of there at some time,'' says Steven Whitney of the Wilderness Society.

However, Mr. Whitney and other environmentalists wonder about Hodel's motives. ``We hope this is not a media ploy to make Hodel look like a strong environmental advocate, because just the opposite is true,'' Whitney says. ``During his tenure this administration has been advocating policies on the public lands that are contrary to sound environmental management.''

Speculation about the motives of the interior secretary has abounded in the past few weeks. Politicians have guessed Hodel may be tweaking the San Francisco Bay area for conveniently ignoring its own water foibles even as it complains about potential environmental degradation in San Francisco Bay and the Sacramento River Delta if any more water is diverted to arid southern California.

Others see signs of partisan politicking between Republican Hodel and northern California's Democratic congressional delegation, which has helped thwart his effort to open more of the state's coastline to offshore oil drilling. Some wonder if he would want to see the O'Shaughnessy Dam replaced by another controversial dam outside of Yosemite, the plans for which were shelved years ago.

Hodel, however, insists he has no ulterior motives. And he has not backed away from his vision. Last week he appeared on network news shows to explain it, and yesterday he called a meeting with environmental leaders to discuss it.

``He seems absolutely sincere,'' said Paul Pritchard, president of the National Parks and Conservation Association, after the 1-hour meeting with Hodel. ``I think he deserves a point right now for having a creative idea.''

The real test will be how much money Hodel requests from Congress to conduct a serious study of the restoration project, environmentalists say.

``Despite all the criticism he gets for being pro-development, the secretary is in favor of a natural park system - of keeping it the way it is,'' says Penny Eastman, a spokeswoman for the secretary. Concern about overcrowding in Yosemite Valley prompted him to think about Hetch Hetchy Valley, ``which has some of the same stunning features of incredible beauty,'' she says.

While Hodel's brainstorm caught virtually everyone offguard, no one was more open-mouthed than the National Park Service officials in charge of Yosemite itself.

``This idea sure didn't originate with the Park Service,'' says Wayne Schulz, a division chief at Yosemite. ``It caught us completely by surprise.''

Park Service plans for alleviating Yosemite's problems have been focused on reducing or eliminating traffic on the valley floor. Over the years, park officials have considered transporting tourists around the valley by train, bus, and even monorail. However, there has never been enough money to build such expensive transportation systems. And feasibility studies indicate there may not be enough suitable land outside Yosemite to build a parking lot where visitors would leave their cars and board a mass transit system.

But would restoring Hetch Hetchy Valley attract enough visitors to provide relief to the overtaxed Yosemite Valley? ``We haven't really had time to determine if that would be the case,'' Mr. Schulz says, noting it would take years, possibly decades, to restore Hetch Hetchy.