The Board of Supervisors unanimously denied an appeal, filed by the Salmon Protection and Watershed Network, of a proposed home in Woodacre that the nonprofit believes would harm fish and increase the likelihood of landslides.

Plans for the 1,900-square-foot home, garage and septic system—plagued by a decade of delays because of cracks in the adjacent road and a major landslide—met criticism at Tuesday’s hearing from SPAWN, the California Department of Fish and Wildlife and a…