SCH Number 2021100070

Project Info

Title

13th Street Bridge Project

Description

The County of San Diego is proposing to adopt a Mitigated Negative Declaration in accordance with the California Environmental Quality Act for the 13th Street Bridge Project. The proposed 13th Street Bridge Project is located on 13th Street and Maple Street between Main Street (SR 67) and Walnut Street in the unincorporated community of Ramona. The project segment of 13th Street/Maple Street is a dirt roadway, with gravel at the Santa Maria Creek culvert crossing. The existing, undersized corrugated steel culvert does not have sufficient capacity to convey the creek water during storm events; flooding at this crossing makes the roadway impassable for motor vehicles and pedestrians during portions of the rainy season. The objective of the project is to provide an adequate and safe crossing that allows for the conveyance of water up to, and including a 100-year storm event. The project would include replacement of the existing culvert crossing with a bridge designed to meet current federal standards, with roadway improvements along 13th Street/Maple Street and Walnut Street, and the addition of stormwater conveyance and treatment features that would ultimately discharge into Santa Maria Creek. The proposed bridge would be a 4-span cast-in-place pre-stressed, post-tensioned concrete box girder structure, approximately 480-feet long and approximately 42-feet wide with three singular-column bents and two abutments. The bridge and approaches would include two 12-foot travel lanes, 3-foot shoulders on each side, and an approximately 8-foot wide multi-use pathway to accommodate pedestrians, bicyclists, and equestrians. In addition, three bridge barriers with a total width of approximately 4-feet, consisting of two edge deck rails and one pedestrian barrier would be installed to separate pathway users from the travel lane and creek. The pathway across the bridge would connect to the existing southern segment near the Ramona County Library and transition users across the bridge to existing and planned trail facilities north of the bridge. The grade of 13th Street/Maple Street would be raised approximately 10-feet at the Santa Maria Creek crossing to comply with current Federal Highway Administration (FHWA) requirements. Storm drain systems are proposed directly to the north and south of the bridge to capture runoff and direct it towards the existing creek. Permeable pavement areas would be incorporated into the project as Green Street features to facilitate meeting water quality requirements and for storm-water management. An existing bioretention basin located south of the bridge that currently treats stormwater from the library and associated parking lot would be redesigned to also accommodate runoff associated with increased impervious areas from the proposed project. The total quantity of cut for the project is approximately 6,200 cubic yards (cy) and the total quantity of fill and import is approximately 13,000 cy. Construction is anticipated to last approximately 12 months. During the bridge foundation construction, dewatering may be required for the project.

2 documents in project