Elkhorn Slough N. Abutment Scour Repair

Caltrans District 5 is implementing a project to repair and reinforce damaged slopes at the Elkhorn Slough Bridge on Highway 1 in Moss Landing, Monterey County. The scope of work focuses on three primary areas: the northwest side, where an abandoned abutment sheet pile wall will be reinforced using buried dead man anchors and rock slope protection; the northeast side, to address scouring at the embankment toe and over-steepened slopes; and one location at the south abutment. To minimize environmental impact, the project mandates the use of bioengineering measures to the maximum extent feasible, strictly prohibiting the use of gabions, concrete mats, tires, and rubble. The project is subject to rigorous environmental compliance and monitoring to protect federally listed species, including the South Central California Coast steelhead, tidewater goby, western snowy plover, and southern sea otter. A qualified biologist must perform pre-construction surveys and daily monitoring, and a 1:1 mitigation ratio for wetland or riparian habitat loss must be implemented. Key administrative requirements include the submission of a Section 401 Clean Water Act Water Quality Certification application and a comprehensive post-construction report featuring as-built drawings and photographs due 45 days after completion. Final acceptance is tied to a two-year monitoring period to ensure successful habitat enhancement and the reduction of invasive species.