Image shows a cross-section look at a berm-style elevated roadway, and an example of a possible fix for South Bay Boulevard in the face of sea level rise. Diagram courtesy SLOCOG
Stating concerns about climate change, sea level rise and public safety, a countywide agency is beginning a process to plan for the future of the only road that directly connects Morro Bay and Los Osos.
The San Luis Obispo Council of Governments, an amalgam of elected leaders that oversees regional transportation planning and funding, just held its first public meeting for the “Morro Bay Estuary Climate Resiliency Transportation Plan.”
“The Plan,” reads a news release from SLOCOG’s John DiNunzio, “will focus on a 2.5-mile stretch of South Bay Boulevard between State Route 1 and Los Osos Creek, including spurs along South Park Road (i.e., Main Street), Quintana Road, and Turri Road.”
This study plans to go beyond just the roads. “Note that the study area also includes the Morro Estuary Natural Preserve and Morro Bay State Marine Reserve. Other jurisdictional zones will also be considered, including the California Department of Fish and Wildlife lands and others.”
South Bay Boulevard has had issues with flooding since the horse and buggy days, no worse however, than the nearly 50 years than when the old, infamous “Twin Bridges” — a 50-yard crossing of Chorro Creek — acted as a choke point for Chorro Creek, backing up and flooding South Bay at the intersection with Lower State Park Road.
That problem reached a pinnacle in March 1995, when torrential rains flooded Twin Bridges and closed South Bay for weeks. That meant everyone traveling between the two towns had to go the long way around — Los Osos Valley Road to Foothill Boulevard and over to Hwy 1 or vice-versa.
Of note, during the school year middle school kids in Morro Bay go to Los Osos Middle School and high school kids from Los Osos go to Morro Bay High, all crossing back and forth on South Bay.
The City of Morro Bay took the project over and finally pushed through Twin Bridges’ replacement; and with the new Chorro Creek Bridge, the flooding of South Bay seemed solved — until the winter of 2023.
Drawing shows how an elevated South Bay Boulevard might be done using a causeway concept. The Council of Governments is launching a study into how to best protect South Bay Boulevard from future flooding and sea level rise. Diagram courtesy SLOCOG
“Winter storms in January 2023,” DiNunzio said, “damaged portions of South Bay Boulevard and caused extensive flooding of the roads and other properties.
“Although construction of the ‘new’ Twin Bridges over Chorro Creek circa 1995 helped to relieve flooding issues and road closures, the roadway is still vulnerable to flooding.”
Indeed, that flooding event in mid-January 2023, which also flooded Main Street at Morro Creek, marked the first time since the new bridge went in that South Bay flooded out. It also flooded further down the road at Quintana and South Bay for the first time.
SLOCOG sees this flooding as only getting worse with sea level rise.
“Combinations of high estuary tide levels with high creek flows,” the release said, “result in greater flooding of the area, particularly in the lower reaches of the tidal creeks [i.e., Chorro Creek and Los Osos Creek].
“With sea-level rise, the impacts and the frequency of road closures are expected to increase dramatically.”
This is also important so long as the Diablo Canyon Nuclear Power Plant is operating. “Road closures due to flood events eliminate connectivity between the communities of Morro Bay and Los Osos and block one of the primary evacuation routes in the event of a radiation accident at Diablo Canyon Nuclear Power Plant.”
Diablo Canyon, which had been scheduled to close in 2025 when its second operating license expired, could now remain open for 5-20 more years.
SLOCOG plans to take an all-encompassing look at all the issues for South Bay’s future, as SLO County is working on a project to replace the Los Osos Creek Bridge.
“SLOCOG’s vision for the Plan includes close collaboration with a wide range of stakeholders, including Caltrans, California State Parks, San Luis Obispo County, City of Morro Bay, City of Los Osos (sic), the MBNEP, as well as community members to co-develop thoughtful and innovative solutions.” (By “City of Los Osos,” DiNunzio is referring to the Community Services District, the closest thing unincorporated Los Osos has to an elected local governing body.)
Further complicating this study, is the goal of also protecting the estuary and its wildlife and habitat. “These wetland habitat areas are part of the State Marine Reserve and Natural Preserve and are critically important for a variety of animals and plants, including some endemic species that can only be found locally.”
He notes that the National Estuary Program (MBNEP) has been working with the U.S. Geologic Survey (USGS) and others, “to study how the wetlands may respond to sea-level rise through natural sedimentation, which will be integrated into this Plan.”
The study’s analysis will be rooted in “nature-based solutions,” DiNunzio said. “The Plan will also increase floodplain resilience, preserve critical habitats, and increase flood protection for public infrastructure.”
They plan to start by identifying “assets” that are vulnerable to sea level rise, essentially low spots along the roadway, which runs just a few feet above sea level. They also want to improve safety for bicyclists on South Bay.
“Although Class II bike lanes are located on the shoulders of South Bay Boulevard,” he said, “mobility is limited to those with the physical ability to safely operate a bicycle adjacent to a highway. Presently there are no ADA-compliant trails around the estuary and this section of shoreline is a known gap in the California Coastal Trail, despite good intentions from California State Parks to envisage a multi-modal connection along the shores of the estuary.”
While the roadway needs protection against sea level rise (compounded by naturally occurring things like king tides), the riders need protection from the drivers.
“One of the outcomes of the Plan is to develop a conceptual design for a new protected bike/pedestrian facility or multi-use pathway connecting the communities of Los Osos and Morro Bay in order to close this gap in the California Coastal Trail.”
He said the LOCSD’s project to run a water pipeline down South Bay to connect with the Chorro Valley Pipeline that brings State Water to Morro Bay. The CSD is designing its project to get about 200-acre feet a year.
SLOCOG’s news release makes a glaring error when he writes, “The City of Los Osos plans to install a new pipe that would route reclaimed water from the new Morro Bay Wastewater Treatment Facility to Los Osos along South Bay Boulevard…”
Ron Munds the Executive Director of the CSD said the pipeline would bring drinking water not reclaimed effluent to town. Nevertheless, that minor mistake doesn’t necessarily negate the opportunity the project presents.
The pipeline project, “presents an opportunity to co-locate the bike trail on top of or adjacent to the pipeline to minimize impacts and disturbance to habitat and the existing roadway.”
The study will delve into all manner of inquiry connected with climate change science.
“Plan development will include GIS mapping and inventories,” DiNunzio explained, “site observations, technical analyses of flood hazards including modeling of the estuary water levels with sea-level rise, opportunities and constraints analysis, development of alternatives, evaluation of alternatives using a benefit-cost approach, and finally drafting the adaptation pathways concept, which will be visualized using innovative virtual reality tools like the Sea-Level Rise Explorer and 360-degree film.”
The study will have a number of consultants, with Environmental Science Associates, taking the lead. RRM Design of SLO will do the transportation and bike path planning, civil engineering and landscape architecture, as well as public outreach.
The Middlebury Institute of International Studies at Monterey will study the economics; and Virtual Planet Technologies is on board to do virtual reality-public outreach; with SLOCOG as staff.
There is also an advisory board being assembled consisting of representatives from Morro Bay, the MBNEP, State Parks, Caltrans, SLO County, and the Los Osos CSD.
DiNunzio said funding for this is coming from a Caltrans Sustainable Transportation Grant for $447,615 with an eye at more grant monies.
“After its completion it will help position the County, State Parks, and the City of Morro Bay to obtain PROTECT Federal funds and/or State Climate Adaptation Capital Funds to further advance the adaptation projects through the next phases of planning, design, and implementation.
“This study is the first step to identify the potential solutions that are suitable and inclusive of the community’s vision and values, and it will provide a clear basis for prioritizing near-term actions and guiding longer term planning to higher amounts of sea-level rise in the future.”
As for timeline, at this time there doesn’t appear to be one, but if the experience of replacing Twin Bridges is any indication, it could be a while. Twin Bridges took over 40 years to get permits and be replaced.
And whatever the plan eventually concludes and identifies as projects to pursue, each would have to undergo environmental analysis and review, and permitting, most likely through the Coastal Commission.
