Work to restored stream bed in Arroyo Creek in Forrest Knolls seen in this Sept. 29, 2010…

A Marin Superior Court judge has issued a tentative ruling largely backing the county in a lawsuit brought by a fish protection group, but left open the possibility of a building moratorium to protect endangered coho salmon.

A final ruling by Judge Lynn Duryee in the 2010 lawsuit filed by the Forest Knolls-based Salmon Protection and Watershed Network is expected in the coming weeks.

In its suit, SPAWN argued that a 2007 countywide plan failed to protect salmon habitat in the San Geronimo Valley in violation of the California Environmental Quality Act.

The county already has general rules prohibiting building within 100 feet of streams; SPAWN wants the county to immediately adopt a more expansive stream conservation area ordinance to set building rules to protect fish in areas such as the San Geronimo Valley.

The county has a plan to do that, but on its own timetable. In her tentative ruling issued last week, Duryee wrote that SPAWN is “essentially asking the county to move this program to the front of the legislative line, without regard to the other competing and diverse needs of the county’s residents. When to prepare and place for consideration the ordinance on the legislative calendar is the consummate discretionary decision. Petitioners have cited no legal authority on facts like these, to support their petition.”

She went on to write that SPAWN is “improperly” seeking to use the law to dictate when the Board of Supervisors should move forward with its plan.

“Petitioners have not sustained their burden to establish that the Board of Supervisors abused their discretion by not enacting the ordinance within the time frame indicated in the (countywide plan),” Duryee stated.

The judge noted, though, that “good cause exists to enjoin the county from approving any development applications for building within the (stream conservation areas) until the ordinance is adopted.”

That sets up the possibility that the court could order a building ban for property owners near streams. In 2008, supervisors enacted a two-year building ban that ended earlier this year, and supervisors subsequently approved the controversial San Geronimo Valley Salmon Enhancement Plan, a set of voluntary measures to protect coho salmon.

Todd Steiner, biologist and executive director of SPAWN, said the tentative ruling supports his organization’s assertions.

“This is a victory for the endangered coho salmon and the reason while we filed our lawsuit — to finally get the county to take action to protect streamside habitat from further degradation,” Steiner said. “The judge ruled that until the county takes action and passes an adequate ordinance to protect the salmon’s critical habitat, no new (building) permits should be issued. The citizens of Marin County should be really pleased that the legal system stepped up here and acted to protect this precious natural resource.”

Supervisor Steve Kinsey noted the judge’s ruling favored the county in almost all the allegations brought in the suit, but acknowledged a court-ordered moratorium would be “Draconian” and hard to swallow.

“This would affect every homeowner in the San Geronimo Valley,” said Kinsey, who represents the area, noting the county and other organizations have spent $17 million to improve fish habitat. “I’m convinced the fish will not be better off if people of the San Geronimo Valley are punished.”