SAN GERONIMO (KPIX) — After nearly twenty years, this multi-million dollar salmon restoration project, is reaching a major milestone.

San Geronimo Creek was dammed in the 1920s to make a swimming pool not knowing it cut off the spawning grounds of Coho Salmon. Now, nearly a century later, the conservation group known as SPAWN is removing it.

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Preston Brown is SPAWN’s Director of Watershed Conservation.

“What was known as Roy’s Dam, we’ve removed the dam, we’ve opened the channel and completely restored it. Now we’re putting in a brand new Pedestrian bridge to link the trails on either side of the creek,” says Brown.

Removing the dam was more involved than first thought. It took nearly two weeks of work for heavy machinery to reach the old dam but time-lapsed video shows once in place, it didn’t take long to rip it out.

“We literally had to remove a hundred years of sediment that had built up behind the dam,” says Biologist and Executive Director of SPAWN, Todd Steiner. “Millions and millions, actually hundreds of millions of pounds of sediment taken out of the creek forever!”

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The creek upstream has returned to its 1920s profile, too. Creek banks are covered in burlap until planted grass can protect it from this winter’s rain, but the big show is the new 10 ton, 100-foot long bridge that will maintain the existing hiking trial.

Construction superintendent, Ron Campbell is proud of the crews work.

“We’re very happy to be here, thrilled to be part of project and to put it all back to its natural state,” says Brown.

It’s a tricky task to lift such a large bridge all at once. Bolts a hundred feet apart must line up perfectly. The bridge itself is placed within 1/8 of an inch in exactly the right spot.

“We’re expecting maybe 500 fish to come up the creek…yeah, up this little creek. You know, with some rain, when the creek swells up, this thing becomes a river”, says Brown.

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This is only phase one. Phase two further upstream starts next summer