Ninety years ago, Hetch Hetchy's fate in Yosemite National Park was decided, but it was not sealed.
On Dec. 6, 1913, near the stroke of midnight, a divided Congress gave up control of the valley. It voted to allow San Francisco to build a dam and flood Hetch Hetchy.
With that vote, San Francisco won water and electricity. The American public lost a treasure.
Today, the Hetch Hetchy Valley lies under 300 feet of water. Nearby, its larger twin, the crowded Yosemite Valley, is on the verge of being loved to death.
The Hetch Hetchy Valley before it was flooded. The Tuolumne River meanders its way westward through the valley. Sacramento Bee archives
These twin wonders of nature, with their breathtaking waterfalls and imposing granite peaks, deserve to be treated as equals. They deserve to be the subject of a debate to rival the Senate battle of 1913.
Should they be reunited? The question is reasonable because the prospect is realistic. Hetch Hetchy's future, contrary to conventional wisdom, is not preordained.
Already, a new chapter is taking shape for Hetch Hetchy.
A computer analysis by scientists at the University of California, Davis, shows that San Francisco and its neighboring counties could get adequate water from three other reservoirs on the Tuolumne River instead of Hetch Hetchy.
San Francisco has said it wants to expand its water system, first by building a pipeline across the Central Valley to carry more Sierra water and, second, by building a new reservoir in the Bay Area to replace one that is seismically unsafe.
To accomplish that kind of expansion, San Francisco will have to push the boundaries of its water rights. That kind of question is usually resolved by the state or the courts.
Since the city is on course to address its water rights issues anyway, this is now an opportune time to examine which use of Hetch Hetchy holds a higher value: as a magnificent public asset in the national park or as a utilitarian project for San Francisco and neighboring counties.
This is also the right time to ask whether a replacement reservoir in the Calaveras hills should be larger than the existing reservoir and whether San Francisco might secure new, additional sources for drought years beyond the unpredictable Sierra.
Put all these factors together and the result is clear. It is possible now to imagine a different future for Hetch Hetchy.
Two leading California Assembly members on water issues - Joseph Canciamilla of Pittsburg and Lois Wolk of Davis - are already pondering such a future. They wrote the Schwarzenegger administration last week urging a full-blown study of Hetch Hetchy. It was a short letter, barely a page. But it broke the political taboo on mentioning the lost valley.
The governor should join them by saying yes to the study. Facts about all the options - from an independent, trusted source - will be crucial. The job best falls to the state and federal governments, which are the stewards of Yosemite, the Tuolumne River and water rights.
In California water wars, peace prevails when government provides the necessary technical information, when water district lawyers protect their clients and when politicians show a willingness to lead, accept change and compromise.
Who will lead on Hetch Hetchy? One possibility is Gavin Newsom, San Francisco's mayor, who has demonstrated his ability to tackle controversial issues.
Another is U.S. Sen. Dianne Feinstein, who long has opposed proposals to restore Hetch Hetchy. Even so, her emerging role as a deal-maker on water conflicts would suggest she could tolerate a study of an idea that she does not personally favor. Crafting an epic deal that protects San Francisco but awards the American public its lost treasure would provide the single, missing piece of her environmental legacy - the Sierra.
A local congressman such as Yosemite's George Radanovich might lead the challenge, through his chairmanship of the House subcommittee on national parks.
And of course there is Gov. Arnold Schwarzenegger, who is insistent that he wants to leave an environmental legacy. It turns out that his top water official, Lester Snow, was working with Environmental Defense on an analysis of restoring Hetch Hetchy when the new governor came knocking to hire him. The governor loves the big stage and the grand gesture. What could be bigger or grander than the restoration of Hetch Hetchy?
The story of Hetch Hetchy already has taken some surprising turns and led to one conclusion: Reuniting Yosemite's twins is hardly fantasy. In fact, if the study provides credible evidence, it is within the nation's grasp. Sometimes the right moment comes along. This has got to be it.