Mount Veeder Road MPM 4.3 and 3.25 Slide Repair Project RDS26-24

Mount Veeder Road near mile post marker (MPM) 4.3 sustained roadway failure when a portion of the road slid down the hillside, threatening the remaining portions of the road. To ensure the future stability of the road and provide for public safety, the County of Napa (County) is proposing to repair the damage by restoring the road and installing a retaining wall. The slide repair will include installing a retaining wall and restoring the damaged section of Mt. Veeder Road. The retaining wall will be a 14-foot-high, 184-foot-long concrete wall supported on drilled piers with tiebacks to allow for the travel lane to remain open during construction and provide additional lateral support to reduce drilled pier depths. A shotcrete facing will also be applied as part of the shoring system during construction to stabilize the excavation and maintain one open lane. To ensure the high wall will adequately carry the load, one row of permanent tiebacks will be installed 6 feet below ground. To restore the asphalt surface and pre-slide drainage patterns at the roadway surface, backfill will be added and the roadway will be repaved. Best Management Practices and erosion control will be implemented, as well as environmental commitments to protect environmental resources, including any potential special-status species or cultural resources that may occur in the project area.