San Lorenzo River Bridge and Kings Creek Bridge Replacement (05-1H470)

San Lorenzo River Bridge and Kings Creek Bridge Replacement (05-1H470)

The California Department of Transportation (known as Caltrans) proposes to replace the San Lorenzo River Bridge (Number 36-0052) at post mile 13.6 and Kings Creek Bridge (Number 36-0054) at post mile 15.5 on State Route 9 in Santa Cruz County, in the unincorporated community of Boulder Creek. The project will remove and replace both bridges with new single-span, standardwidth structures consisting of 12-foot-wide lanes and 8-foot-wide outside shoulders. Existing metal beam guardrail will be removed and replaced with a standard Midwest Guardrail System which will be connected to the bridge rail by Midwest Guardrail System Transition Railing Type WB-31. A taper will be paved on each side of the bridge to transition the new 8-foot-wide bridge shoulder to the existing roadway shoulder. Work in the streambeds is proposed and will require use of a temporary diversion system to dewater work areas for demolition and removal of existing bridge abutments and piers. Because the existing abutments at both bridges were constructed by casting materials directly into the exposed bedrock within the stream channel, the abutments will be partially removed in an effort to minimize removal of bedrock and alteration of the stream channel. Abutments and side support columns at the San Lorenzo River Bridge will be removed to the extent required to make space for the new bridge abutments, and therefore will not be removed to original grade. At the Kings Creek Bridge, a portion of existing sacked concrete (0.049 acre), located approximately 10 feet above the Ordinary High Water Mark, along the existing northern abutment, will be replaced with rock slope protection. The existing pier located below the Ordinary High Water Mark will be removed to approximately 3 feet below original grade. This will result in a 22-square-foot increase in critical habitat area for special-status fish species at Kings Creek. It is anticipated that all work will occur within the existing state and County road rights-of-way, and no new right-of-way will be necessary. Existing utilities that would conflict with construction operations will be relocated by the owner prior to and during construction. The proposed bridges will be constructed along the existing State Route 9 alignment. State Route 9 is a rural and mountainous highway that travels 35 miles from State Route 1 in the city of Santa Cruz along the Pacific Coast to State Route 17 in the town of Los Gatos at the southern edge of the greater San Francisco Bay Area. It passes through the San Lorenzo River Valley and the Saratoga Gap in the Santa Cruz Mountains. The project area is a section of the travel corridor that is in a rural setting surrounded by residential land uses.

Santa Cruz