It would be lovely to be able to talk seriously about removing the dam in Hetch Hetchy Valley, to restore John Muir's "holiest temple" and expand hiking and camping areas in Yosemite. But I'm not ready to go there right now -- and to claim that giardia in the water  is a good reason to dynamite O'Shaugnessy Dam is a bit beyond silly.
The Chron writes about the Restore Hetch Hetchy movement every now and then, and there's always a lot of talk about the water system. But the paper never seems to mention the other part of the dam -- it generates electricity. And it was, and remains, the lynchpin of what's supposed to be a public power system in San Francisco.
Congress would never have allowed San Francisco to build the dam if it was just for water. The whole deal, memorialized in the Raker Act of 1913, hinged on the city using the dam for both water and power, and using the power to establish a public-power beachead in Northern California  to compete against Pacific Gas and Electric Co. Tear down the dam and the city loses not only a pristine water supply but enough non-fossil-fuel electricity to power a significant part of its electricity needs.
I know that there's a lot of controversy about large hydro as renewable power, but the dam's already there, and I think everyone agrees that existing hydro is a better source of electricity than coal, oil, natural gas or nukes.
In a perfect world (and we'll get there one day), San Francisco would have a municipal power system that relied entirely on solar, wind, and tidal energy. And we'd have a Bay Area water system that reduces use dramatically, recycles gray water, shifts agriculture to drought-resistant sustainable crops, replaces lawns with native ground cover and requires far less fresh-water input every year. At that point, the dam will be redundant and pointless. Bombs away.
But until we no longer rely on a privately-controlled electrical grid based on fossil-fuel and nuclear generation, we just can't afford to lose the dam. Why the Chron never talks about that side of the equation remains one of the great mysteries of local journalism.