Modification of Existing Culvert Outfall along Line B downstream of Harrison Street in the City of Oakland, Alameda County, California, Zone No. 12 Project

The Alameda County Flood Control and Water Conservation District is undertaking the Modification of Existing Culvert Outfall along Line B downstream of Harrison Street in the City of Oakland, California, Zone No. 12 Project. This initiative is driven by the Zone 12 Drainage Master Plan, which identified that the current 14.5 foot wide by 6 foot high reinforced concrete box culvert between Harrison Street and 26th Street lacks the capacity to handle a 100-year design storm event. The project aims to improve the underground storm pipe outfall to meet these design standards and prepare the structure for a future additional underground culvert under Harrison Street and 27th Street. The scope of work includes the installation of a 50-foot-long, 6 foot wide by 6 foot high reinforced concrete box culvert bypass beneath the sidewalk adjacent to the existing structure. Technical requirements involve the removal of 14 linear feet and 10 cubic yards of the existing concrete channel wall on the western side, the installation of a warped concrete wing wall conformed to the existing channel wall, and the removal and reconstruction of approximately 128 square feet of the existing concrete channel apron. This project is classified under NAICS code 237990 and has been granted a Notice of Exemption based on California Fish and Game Code Section 711.4 and Public Resources Code Section 21152 due to the minor nature of the alterations.