Youngs Bay Cap Repair | PERCo, Astoria, OR

As part of an Oregon DEQ voluntary cleanup, an intertidal cap and riprap armored shoreline were constructed at the PacifiCorp Youngs Bay property. The location of a former manufactured gas plant, the site was characterized by a tar body that extended 400 feet onto and across a marine mudflat. An articulated block mat (ABM) covered with habitat material was installed as the composite cap.

DOF’s initial project involvement included:

• Updating the original site characterization report
• Creating the conceptual design for the remedial cap
• Developing a conceptual construction strategy to place ABM and fill with concrete during daylight low tidal cycles
• Preparing engineering evaluation and cost analysis report

The owner chose to use another firm for the design. Post construction coastal erosion degraded the habitat layer and shoreline armoring.

DOF’s additional project involvement included:

• Completing an erosion analysis and repair design for habitat capping material, riprap, and ABM
• Providing construction management for repairs and documenting observations in daily reports and photos
• Completing on-going inspections and monitoring, sampling, analysis, and report preparation
• Assisting with regulatory agency negotiations
• Preparing support documents including permit applications, O&M Plan, design memorandum, and construction completion reports