White Sulphur Springs Road Slide Repair Project RDS26-37

The White Sulphur Springs Road Slide Repair Project (RDS26-37) is a forecast procurement by Napa County for the stabilization and repair of a landslide located in St. Helena, California. The project involves the construction of a 192-foot-long, 10-foot-high soldier pile retaining wall to stabilize a steep slope on the south side of the roadway. Technical specifications include the installation of structural steel soldier piles embedded in 30-inch diameter holes filled with lean concrete, spaced at 8 feet on center, with precast concrete lagging placed between them. Additional scope includes filling and repaving the roadway to restore the asphalt surface and pre-slide drainage patterns, hydroseeding, lining a roadside ditch with concrete, and the removal of surplus slide material. The project is categorically exempt from the California Environmental Quality Act (CEQA) and must adhere to Napa County Storm Water Program requirements using Best Management Practices for erosion, trash, and dust control. Significant environmental restrictions are in place, including a limited operation period from February 1 through July 31 to protect the Northern Spotted Owl, unless protocol surveys prove otherwise. Work in suitable aquatic habitats for steelhead and protected frog species is restricted to the window between June 1 and October 15. Mandatory requirements include pre-construction and daily clearance surveys by a qualified biologist, environmental awareness training for all personnel, and a strict prohibition of pets and firearms on the project site.