March 2023 Emergency Storm Repairs, Canada Road Emergency Road Slip-out and Culvert Repair, Kings Mountain Road Slip-out Repair

March 2023 Emergency Storm Repairs, Canada Road Emergency Road Slip-out and Culvert Repair, Kings Mountain Road Slip-out Repair

Cañada Road is a two lane, local road that connects to State Route 92 to the North and Edgewood Road /Phleger Road to the South. A portion of Cañada Road northbound shoulder is currently blocked due to the embankment and culvert failure on the east side of the roadway. Heavy rains during the March 2023 storm events overwhelmed the culvert inlet along the east side of the road, which conveys flow from an unnamed tributary to Upper Crystal Springs Reservoir on the west side of the road. High flows in combination with saturated slopes triggered the sinkhole, which measures approximately 50-ft across. Repair and stabilization are necessary for maintaining the integrity of the roadway, public safety, and access for residents and emergency vehicles. This emergency repair project will include removal and in-kind replacement of the existing, damaged corrugated metal pipe (CMP) culvert, removal and replacement of the existing culvert headwall at the inlet side, addition of wingwalls to culvert headwall, rebuilding the embankment slope, and installation of erosion control measures including revegetation. Work will also include, but is not limited to, clearing and grubbing as necessary, installing sheet piles along the vertical slope along the roadway to protect the active PG&E 230 kV electric transmission line and gas line during excavation, removal and replacement of the existing metal beam guardrail, and removal and replacement of damaged AC as needed. If deemed necessary upon further inspection, clearing and lining the existing, intact section of the CMP that runs under Cañada Road may also be performed. An unnamed drainage flows west through the failed culvert to Crystal Springs Reservoir. Project activities are anticipated to begin in mid to late July 2023 and will take approximately 30 days to complete. An additional slip-out repair will occur on Kings Mountain Road approximately 2.0 miles west of Hwy 84. A portion of the road is unsupported due to the recent slip of the embankment that occurred due to the March 2023 storm events, and the road is restricted to one-lane traffic at the site. Immediate repair and stabilization are necessary for maintaining the integrity of the roadway, public safety, and access for residents and emergency vehicles. If left untreated, failure of the road may continue into the second lane which is displaying signs of stress, risking full closure of the road. Proposed repairs consist of reconstructing and stabilizing the embankment using soil nails and shotcrete, and installing a guardrail or similar barrier. Project activities are planned for August 2023, immediately following completion of Caltrans’ repairs on Hwy 84.

San Mateo

Unincorporated

San Mateo