During the storm event that started in January of 2023, significant damage occurred at Dry Creek Road MPM 11.6, which is located in the unincorporated Napa County. Dry Creek Road MPM 11.6 sustained road and bank failure consisting of downslope failure on the northern side of the roadway, where a portion of the road slid down the hillside threatening the remaining portions of the road. The slide is approximately 100 feet long by 12 feet wide.
The proposed repair to the slide is approximately 124 foot-long concrete grade beam wall supported by 24” concrete CIDH (cast–in-place-drilled-hole) piles. The grade beam wall depth is between 8’ to 14’. The piles depth is approximately 30’. There are approximately 60 linear feet of roadway payment rehabilitation (grinding and re-surfacing existing pavement) and 85 linear feet of roadway payment re-construction (removing old asphalt/aggregate base and replacing with new asphalt/aggregate base).
Engineer Estimate: $700,000.