County supervisors last week approved plans to reconfigure a 120-foot box culvert set in Woodacre Creek that runs under Railroad Avenue, hoping to ease passage for juvenile coho salmon and steelhead trout seeking the sea. Last year, the county secured a $235,000 grant from the California Department of Fish and Wildlife to outfit the culvert, which has strangled water flows in sections of the creek and washed out sediment since its construction around 50 years ago. The reconfiguration will involve rock weirs, log structures and concrete baffles to shore up a steep drop in the creek at Railroad Avenue that has created a tricky jump for young fish to maneuver. The project also aims to improve creek flows for 365 feet downstream by stabilizing and revegetating banks. “This is a really important refuge for juvenile salmon,” said Kallie Kull, a planner for the county’s Fish Passage and Creek Restoration Program. “The project will create deep pools of cold water, and the logs will create cover to keep the juveniles from being washed out.” Supervisors have pitched $180,000 to meet the project’s $415,000 budget, and the 45-day construction period is is slated to begin in mid-August. The culvert retrofit marks the tenth project—eight of which were located in the San Geronimo Valley—that the county’s fish-passage program has undertaken since its formation in 2005, totaling around $3 million in costs. Three more projects in the valley are in the design phase. The Marin Municipal Water District’s latest juvenile salmon count—9,000—continues an above-average trend, but represent a second straight year of decline from a 2014 peak of 15,000. According to the district’s fisheries ecologist, Eric Ettlinger, the culvert project could help juveniles reach the sea more easily, but would not affect high-flow creek sections that disrupt migration—a possible cause of the recent decline in smolts. One of the last havens for coho salmon in the state, populations in the Lagunitas Creek watershed over the last 60 years have plummeted from around 6,000 down to about 400 female spawning fish—a more-than 90-percent drop, according to Fish and Wildlife.