Hetch Hetchy replacement reaches milestone

On Friday, water for millions of people in the Bay Area is flowing through a massive new pipeline in the East Bay. It marks a major milestone for the Hetch Hetchy repair project and only ABC7 was there as officials made their final checks.

We saw workers hang precariously in a cage over a 12-story deep hole. At the bottom of the hole was an engineering feat now delivering water to more than two-and-a-half-million people in four Bay Area counties.

"It's really about a decade of work to get to this point. We're very excited because the Bay Area is safer today than it was even yesterday," said Daniel Wade, the Director of Water System Improvement for the San Francisco Public Utilities Commission.

The $340-million project is part of a massive plan to secure the water supply in the region. The new tunnel replaces a pipeline completed in the 1930's.

"On the west side of the tunnel is the Calaveras fault and on the east side is the Hayward fault, so in a major earthquake, there was significant concern that there could be a disruption to the water system," said Wade.

Not anymore.

"This tunnel is designed to resist that earthquake and continue to deliver water to the customers," said Wade.

Voters approved a $4.8-billion ballot measure in 2002 to repair and replace the aging Hetch Hetchy water system.

An engineering marvel at the time, the system of pipes, dams, and reservoirs carries water 167 miles from Yosemite National Park, across the Central Valley, and into the South Bay before going up the peninsula to San Francisco.

David Tsztoo is the Project Manager. He said, "This project had a lot of technical challenges inside the tunnel as well as outside the tunnel."

In 2013, we showed you the view hundreds of feet below ground. That's when workers tore through the final bits of earth to complete this three-and-a-half mile long tunnel. Video provided by the San Francisco Public Utilities Commission captured the moment when miners drilling from Fremont met another crew from Sunol.

Tsztoo said, "We had to deal with squeezing ground, heavy groundwater intrusion during the work, and hard rock, and soft rock, and everything in between."

It is dangerous work, critical to securing a reliable water system in the Bay Area.

The San Francisco Public Utilities Commission is now turning its attention to completing their next big project, a new Calaveras Dam. Prep work on that project is already well underway.

Written and produced by Ken Miguel