Biology Professor Describes How Dams Impact the Environment

Hetch Hetchy damHetch Hetchy Valley has been described as “Yosemite’s Twin.” John Muir, the father of American environmentalism, fought until his dying day to block the construction of the dam that flooded the valley to provide a reservoir for San Francisco’s drinking water.

“It was the first great battle of the American wilderness,” said Mike Marshall, executive director of Restore Hetch Hetchy, during a panel discussion at Saint Mary’s last week. The panel, which also featured Michael Marchetti, the new Fletcher Jones Professor of Biology at Saint Mary’s, was introduced by Roy Wensley, dean of the School of Science, and moderated by Mike Taugher, environmental reporter for the Bay Area News Group.

In the past few years, there have been growing calls for the restoration of Hetch Hetchy Valley to its pristine state -- a high mountain meadow filled with flowers and grasses, surrounded by soaring granite cliffs and rushing waterfalls. Even actor Harrison Ford has leant his support by appearing in a short film about the valley. Watch a preview of the film.

Marchetti, who has studied the impact of dams on watersheds throughout California, described how dams alter the ecology of watersheds, increasing the number of invasive species and ultimately contributing to the extinction of some fish species.

He argued that the land use protections we have now aren’t protecting our aquatic wildlife and said restoration of the valley would be “a big step toward restoring native species,” he said.

Critics of the plan to restore Hetch Hetchy Valley suggest that removing the dam would threaten the quality of San Francisco’s water supply, but both Marchetti and Marshall said that downstream reservoirs, such as Don Pedro Reservoir near Highway 49, could provide storage for nearly all of the water now held in the valley.  

When Marchetti first came to California from the East Coast, his first expedition into the Sierra took him to Hetch Hetchy Valley on a hiking trip in early spring, when the snow was still melting and the waterfalls were roaring. Clearly, it made an impression on him, and he welcomed calls for a conversation on the decision to build a reservoir for San Francisco in one of the most spectacular mountain valleys in the Sierra.

View a video of Marchetti talking about Hetch Hetchy Valley and the impacts of dams on the environment. 

Marshall said his organization plans to bring the issue to a vote by putting an initiative on the ballot for the November 2012 election. The initiative would call on San Francisco to develop a plan to restore Hetch Hetchy Valley, and that plan would then be placed before the voters for a final decision.

He criticized the San Francisco Public Utilities Commission, which controls the reservoir and was invited to send a representative to the panel discussion but declined. Although he’s a San Franciscan, he also criticized the people of his city for ignoring the issue.

“San Francisco has been given a pass because of its reputation as a ‘green’ city. If this were L.A. taking water from Hetch Hetchy, it would be ‘game over,’ ” he said.

Marshall acknowledged that the cost of restoration, estimated at $1 billion to $3 billion, is a hard sell in these economic times but he argued that the value of Hetch Hetchy Valley is beyond measure and that its restoration would better reflect the city and the nation’s new emphasis on sustainable development.

“The most exciting part would be witnessing this incredibly iconic place come back to life literally before our eyes,” he said.

Learn more about the campaign to Restore Hetch Hetchy Valley at hetchhetchy.org.

Watch the complete film about Hetch Hetchy Valley with Harrison Ford.

The panel was presented in collaboration with the Saint Mary’s College Museum of Art’s centennial exhibition of paintings by William Keith, a friend of John Muir who was renowned for his sweeping portraits of the Sierra. A painting by Keith of Hetch Hetchy Valley -- as it looked before the dam was built -- is now on view as part of the exhibition, which runs through December 18.

Maps & Directories

Mailing Address

Saint Mary's College of California
1928 Saint Mary's Road
Moraga, CA 94575
(925) 631-4000
Google Map | Campus Map | PO Boxes