How San Francisco Keeps Its Carbon Footprint Down

Terry Jeffrey
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Posted: Jun 01, 2016 3:30 PM
How San Francisco Keeps Its Carbon Footprint Down

Not long before the start of the NBA playoff game between the Golden State Warriors and the Oklahoma City Thunder on Monday night, the television screen flashed to a panoramic view of the San Francisco skyline -- as seen from the East Bay.

A bank of early evening fog floated into the city from the West, rolling off the unseen Pacific.

High-rise buildings stood in silhouette before that bank of fog, many stretching out in territory to the south of the Transamerica Pyramid.

San Francisco is still a city on the rise -- with an increasing population packed into an urban peninsula less than 50 square miles in size.

From 2001 to 2015, according to Census Bureau estimates, the city's population grew from 770,723 to 864,816.

Where does this city -- nearly surrounded by salt water -- get fresh water to supply that population?

Most of it comes from the Hetch Hetchy watershed in Yosemite National Park, which is beyond the San Joaquin Valley and up in the Sierra Nevada Mountains in an area about 180 miles by road from the city.

More than a century ago, when San Francisco was seeking to develop this watershed for water and power, John Muir and the Sierra Club stood against it.

The January 1908 edition of the Sierra Club Bulletin featured an essay by Muir (available on the Sierra Club website) condemning the dam that the city proposed building across the Tuolumne River to flood the Hetch Hetchy Valley. (This writer's grandfather, a physician and a native of Yosemite Valley, would later work on the city's Hetch Hetchy project.)

In his essay, Muir rightly paid tribute to the beauty of the Hetch Hetchy, which he appropriately likened to Yosemite Valley itself. But then Muir ripped those who would build a dam there.

"These temple destroyers, devotees of ravaging commercialism, seem to have a perfect contempt for Nature, and, instead of lifting their eyes to the mountains, lift them to dams and town skyscrapers," he wrote.

Today's San Francisco Public Utilities Commission -- part of the city's government -- speaks of the Hetch Hetchy reservoir as source of "high quality" water and "clean" power.

"The Hetch Hetchy watershed, an area located in Yosemite National Park, provides approximately 85 percent of San Francisco's total water needs," says the commission's website.

"Spring snowmelt runs down the Tuolumne River and fills Hetch Hetchy, the largest reservoir in the Hetch Hetchy water system," it says. "This surface water in the Hetch Hetchy Reservoir is treated, but not filtered because it is of such high quality."

The commission's website features a "Frequently Asked Questions" page on the reservoir and power system.

One basic point it makes is that "local precipitation in the San Francisco Bay Area is not sufficient to consistently supply the diverse water needs of 2.6 million commercial and residential customers."

It then asks: "Is Hetch Hetchy hydropower renewable and clean?"

"Yes," it answers. "Hetch Hetchy hydroelectric energy is clean, efficient and dependable. Hetch Hetchy hydroelectric energy does not emit any greenhouse gases, produce harmful radioactive byproducts, or leave behind any waste or byproduct of any kind. The Hetch Hetchy Power System supplies 100 percent of San Francisco's municipal energy usage and lessens its reliance on costly energy purchases for municipal use, such as City streetlights, SF General Hospital, SF Airport, SFUSD public schools, and the MUNI transportation system."

The FAQ sheet also addresses the question of whether demolishing the dam would be good for the environment now.

"The carbon footprint of the existing system is one of the smallest of any water system in the United States," it says. "Removing the dam would require system-wide filtration and almost certainly pumping of water, both energy-intensive processes that would increase our greenhouse-gas emissions."

San Francisco, according to its public utilities commission, keeps its carbon footprint down today with the dam that John Muir opposed building more than a century ago.

In a utopian world you could have both a city like San Francisco, built on a peninsula between an ocean and a bay, and never need to dam a mountain valley -- let alone the magnificent Hetch Hetchy.

But in the real world people need water and have a right to collect and use it wisely. The Americans who built the Hetch Hetchy reservoir did just that and the people of San Francisco benefit from their exertions every time they turn their tap.