The purpose of the proposed project is to secure the track bed in its existing alignment. A slide occurred approximately 0.2 mile north of the proposed project area on February 28, 2021 after an existing seawall collapsed. The seawall collapsed because of ongoing wave erosion the undercut the foundation of the seawall, causing the artificial fill the wall was securing to fall onto the beach below.
The proposed project area is very similar to the area that collapsed in February 2021. The proposed project area consists of an existing concrete seawall that was built over 100 years ago that secures approximately 20,000 CY of artificial fill. After the seawall at MP 245.2 collapsed, project engineers studied the seawall in the proposed project and determined that there is an imminent risk of failure until it can be stabilized. If left in its existing condition, there will be a significant risk to public safety due to the active and episodic nature of the bluffs. Amtrak’s Pacific Surfliner intercity passenger rail service through the proposed project area is the nation’s second busiest, serving six counties and 351 miles of the southern California coastline. In addition to Amtrak, this rail corridor is shared with COASTER commuter rail services and Burlington Northern Santa Fe (BNSF) Railway and Pacific Sun freight services.
A Right of Entry permit from the State of California is required for access to the proposed project area. The proposed project consists of installing 47 Cast-in-Drilled-Hole concrete piles in a row directly west of the existing seawall at MP 245.4 with a 2-foot wide slurry trench in between the existing wall and the piles. The 32-foot deep piles will be drilled into the ground and will be capped by a concrete grade beam. This concrete grade beam and a small portion of the piles may become visible if the beach sand is washed away in winter storms. The concrete will be colored to match the existing surroundings. This pile cut off wall will reinforce the existing seawall and protect the bottom of it from being undercut by wave-based erosion, which is what caused the seawall at MP 245.2 to collapse. Access through an existing State Parks parking lot, through an existing beach access road, and through State Park land is required to reach the proposed project area, which is located on land owned by the North County Transit District.