Spawning obstacle

Swimming upstream is hard enough for salmon and steelhead running Petaluma's Adobe Creek.

But a man-made obstacle -- a concrete bridge at Adobe Road -- is making it next to impossible.

A 12-foot opening in the structure is jammed with rocks and sediment, forcing spawning fish to abandon the innate goal of reaching the deep ponds atop Sonoma Mountain.

Instead, they're laying eggs in shallow water closer to the Petaluma River, where they have less chance of survival, said Tom Furrer, a wildlife teacher at Casa Grande High School and founder of the campus fish hatchery.

Furrer is calling on government agencies to replace the bridge with a wider span that will allow the creek to flow more naturally and spare the vanishing fish.

"Once this comes out, we're clear to the mountain," said Furrer, as he walked beneath the bridge Thursday in galoshes and a hard hat. "I can sit back and say, 'We've made a difference here.' "

But whether anyone will take on the project that could cost up to $600,000 is uncertain.

Sonoma County road officials said the box culvert built in 1929 is structurally sound and not in need of replacement.

Dave Robertson, the county roads chief, said there are about 50 similar projects under way and not enough money to do them all. "The fact of the matter is we have other bridges in the county with higher prioritization," he said.

Pat Rutten of the National Marine Fisheries Service said fish are getting through despite problems created by the bridge.

He said coho salmon in the Russian River are at a greater risk of extinction, and that's where limited resources will likely be applied.

"Steelhead are not in that situation," said Rutten, who heads restoration projects in the region for the federal agency.

Casa Grande students under Furrer have been working the past 25 years to conserve fish habitat on Adobe Creek, which had been run dry by city water diversions.

Starting in the early 1980s, the United Anglers of Casa Grande hauled truckloads of illegally dumped tires, refrigerators and other trash from 7½ miles of creek and planted thousands of trees along its banks.

Students raised money to build a campus fish hatchery that has since grown into a state-of-the-art facility featured in national magazines and TV documentaries.

About 10 years ago, Furrer's group built a fish ladder in the creek to help spawning fish clear the culvert. Boulders were strapped together with steel cables and a terrace system was installed in the channel.

But the effects of rushing water from winter storms have taken a toll. The narrow opening upstream clogs with boulders and wood and the fish ladder frequently fills with sediment, Furrer said.

Rocks are thrown downstream, ruining ponds that spawning fish need to use as they leap against the current, Furrer said. A wider bridge would solve the problem, he said.

With dwindling numbers of fish running the creek each year, the situation must be fixed before it's too late, Furrer said.

"I'm near retirement," said Furrer, 53. "I want this out of here before I go."

You can reach Staff Writer Paul Payne at 762-7297 or paul.payne@pressdemocrat.com.