TO: Board of Supervisors
FROM: Steve Lederer, Director of Public Works
REPORT BY: Liang Chin Su, Assistant Engineer
SUBJECT: Award of Construction Contract and Approval of Amendment No. 1 to Agreement No. 260302B for the "550 Wall Road Landslide Repairs Project", RDS 26-38.
RECOMMENDATION
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Award of Construction Contract to North Bay Excavation, Inc. of Valley Ford, California in the amount of $567,058 for the "550 Wall Road Landslide Repairs Project", RDS 26-38 (Project 26028); and approve and authorize Amendment No. 1 to Agreement No. 260302B with ADKO Engineering, Inc. increasing the contract maximum from $319,389 to $356,740 to provide additional engineering services for the Project. (Fiscal Impact: $900,000 Expense for the construction contract and other project costs; General Fund, Reallocation of Budget; Discretionary)
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BACKGROUND
Two slides occurred on Wall Road in November of 2025: one adjacent to the slide at 555 Wall Road that developed during the 2019 storms, and a second approximately 500 feet north of the first. The 2019 Wall Road slide remains mired in the FEMA review process and will move forward to construction once the necessary approvals are received. Both 2025 slide locations exhibit roadway and embankment failure along the north side of the roadway, where portions of the pavement and supporting slope have moved downslope, compromising the stability of the remaining roadway. The slide areas are approximately 70 linear feet and 30 linear feet in length, respectively. The designed repairs for both locations are the construction of reinforced concrete retaining walls, approximately four to six feet in height, supported by cast-in-drilled-hole piles. In addition, approximately 100 feet of roadway, 42 feet in width, will be reconstructed and paved at each slide location to restore roadway integrity and pavement conditions.
On March 10, 2026, the Board of Supervisors authorized creation of the "550 Wall Road Landslide Repairs Project", R...
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