County Wants to Replace South Bay Bridge

Written by Estero Bay News

August 27, 2021

County Supervisors were expected to approve moving forward on a project to replace a bridge on the main road linking Los Osos and Morro Bay.

“The South Bay Boulevard Bridge,” reads a report from the County, “is located between Los Osos and Morro Bay and is a Diablo Canyon Power Plant evacuation route. Based on an Earthquake Evacuation Study performed by Pacific Gas & Electric Co., the South Bay Boulevard Bridge was identified as having high potential for damage in a significant seismic event.”

Caltrans studied the bridge’s structural integrity under current earthquake standards, and determined that the replacement is eligible for Federal Highway Administration funds to pay for it.

The plan is to build a new bridge over Los Osos Creek right next to the existing bridge so traffic lanes can remain open during construction. Once completed, the road would be directed onto the new bridge, the old bridge torn down and the creek “restored.”

The new bridge would be 50-feet wide and 300-feet long. The existing bridge is 36-feet wide and 200-feet long.

The new bridge would have wider shoulders for bike lanes and sidewalks for pedestrians, according to the report with a traffic lane in each direction.
The project is estimated to cost some $19 million and “is dependent on acquiring permits from the resource agencies and future allocation of (FHWA) Bridge Program funds.”

Crossing a stream like Los Osos Creek is a complicated effort with numerous agencies — both State and Federal — having to review and sign off on plans. It can take years to wade through.

For example, the County and City tried to replace the old “Twin Bridges,” a pair of short, wooden bridges, located a couple of miles further down South Bay Boulevard and spanning Chorro Creek.

Twin Bridges was subject to flooding every winter forcing school children on buses and residents to drive to San Luis Obispo and back up Hwy 1 or Los Osos Valley Road, depending on direction of travel. The detour added about a half hour to the trip.

Some 35 different agencies were involved and it was over 40 years before the project finally got approved and the “Chorro Creek Bridge” was built, under the leadership of the City. This even though Caltrans had repeatedly deemed the Twin Bridges as substandard, deteriorating, and in need of replacement.

With this project, the County is issuing a “Mitigated Negative Declaration,” with regards to the California Environmental Quality Act (CEQA), which means there are no impacts to the creek environment that can’t be mitigated.

“The Environmental Division Manager,” the County report said, “found that the proposed project will not have a significant effect on the environment with inclusion of suitable mitigation measures that are designed to avoid and/or reduce project related impacts to insignificant levels.”

The so-called “Neg-Dec” review covered: “aesthetics, air quality, biological resources, cultural resources, geology and soils, hazardous materials, hydrology and water quality, recreation, and tribal cultural resources.”

As for how the County will lessen impacts, “Mitigation measures associated with the project include, but are not limited to: implementing standard vehicle emissions and dust control during construction, preconstruction surveys for special status species, worker environmental awareness training, restricted refueling areas, use of suitable Best Management Practices, and hazardous waste handling and disposal measures.”

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