SPUR Ocean Beach Master Plan for San Francisco – Strategies for Great Highway
The Ocean Beach Master Plan (OBMP) provides a long-term strategy for responding to sea-level rise impacts anticipated along the 3.5-mile stretch of San Francisco’s Ocean Beach, and suggests recommendations for adapting the Great Highway, which runs adjacent to the beach. The strategy focuses on the protection and relocation of transportation infrastructure, including: (1) rerouting the southern portion of the Great Highway; (2) protecting and restoring the shoreline and beach; (3) reducing the width of the Great Highway; (4) repairing seaside dunes; (5) facilitating faster travel between Golden Gate Park and Ocean Beach; and (6) improving bicycle paths and sidewalks near Ocean Beach. While the OMBP has no legal effect, the plan is intended to serve as guidance to the federal, state and local entities that have authority to implement the actions included in the plan.
Ocean Beach is highly exposed to erosive effects of the Pacific Ocean. During storms in 2009-2010, parking lot foundations and the highway shoulder were threatened by collapse due to erosion that at some places caused the beach to recede 40 feet inland. The receding shoreline threatens to damage critical infrastructure: the Great Highway, the Lake Merced Tunnel, and a wastewater treatment plant. The Great Highway, built on an artificial foundation of sand, is an important traffic artery for local residents and regional travelers alike. The highway and nearby parking lots have been undermined by erosion in recent storm events, but lack of coordination among regulatory authorities (including city, county, state, and federal entities) has hampered efforts to implement proactive countermeasures.
To assess future impacts to the Ocean Beach region, SPUR relied on climate projections provided in the State of California Sea-Level Rise Interim Guidance Document. The study assessed the potential impacts to the region based upon projections of 14 inches of sea-level rise by 2050 and 55 inches by 2100. Projected impacts for the study region include more frequent and more severe coastal storm surges and worsening erosion. Acknowledging the uncertainties inherent in projecting climate impacts, the OBMP suggested an adaptive management approach for the region, suggesting that localities undertake successive actions on the basis of physical triggers, such as a particular amount of beach erosion, instead of set timelines. This adaptive management strategy will allow recommendations to be implemented in a flexible manner, evolving as physical conditions change and political and fiscal challenges are addressed.
The OBMP management strategy concludes by recommending six “Key Moves,” the first three of which are most relevant to transportation infrastructure.
- Reroute the Great Highway inland and away from the shore, offloading traffic from its southern portion onto minor roadways that are better protected from erosion. Consider allowing the southern reach of the Great Highway to be retuned to recreational areas and parking. This portion of the Great Highway is now protected with boulder revetments, but it is frequently closed.
- Consider a managed retreat strategy that would protect critical infrastructure while restoring the beach and improving recreational access. The important Lake Merced Tunnel is buried deep within a large sand berm that forms the foundation for the southern portion of the Great Highway. By removing and relocating parts of the southern highway, the city could replace the current seawall protecting these assets with a longer, shallower defense system that dissipates tidal energy more effectively while providing more useable beach. The underground Lake Merced Tunnel would be armored with a low-profile structure made of stone or concrete, on top of which would be piled cobblestones that would absorb tidal energy, reducing erosion. Sand dredged by the U.S. Army Corp of Engineers would be placed atop the cobblestones to provide another layer of buffer, but would need to be maintained with consistent renourishment.
- Narrow the Great Highway along the middle portion of Ocean Beach. Although this could lead to higher traffic on adjacent roadways, traffic analysis, signage, and traffic calming measures could persuade regional drivers to use the higher capacity roads further inland (such as Sunset Boulevard). By narrowing the highway, managers could make space to restore dunes that are receding toward the highway.
Because the OBMP has no legal effect, its funding and implementation is contingent on action by a range of agencies at all levels of government. To ensure implementation the plan lays out concurrent “implementation tracks,” described below. The OBMP was developed by the San Francisco Planning and Urban Research Association (SPUR), which is a member-supported nonprofit organization that provides planning assistance to the San Francisco Bay Area. SPUR will maintain a role as coordinator and advocate for implementation of the OBMP:
- To implement the transportation-related adaptive measures, SPUR will bring together consultants and city agencies, through the Mayor’s Office of Economic and Workforce Development (MOEWD), in order to ensure that the complex reconfiguration of intersections and traffic lanes takes place smoothly. The San Francisco Metropolitan Transit Authority (SFMTA) will take the lead on preparing an Environmental Impact Report (EIR) for the relocation of the Great Highway and the reconfiguration of the minor roadways.
- The National Park Service, Army Corps of Engineers, San Francisco Department of Public Works, and San Francisco Recreation and Parks Department are all collaborating to conduct a coastal engineering and feasibility study, a pilot program to investigate the benefits of cobble revetments, and an agreement to jointly manage any interim coastal protection strategy.
- Traffic analyses and road configuration assessments are jointly funded by the San Francisco Municipal Transportation Authority, the San Francisco Planning Department, the San Francisco Recreation and Parks Department, and the San Francisco Department of Public Works.
- The City of San Francisco has sought federal funding (unsuccessfully) to renourish portions of the beach.
- Finally, SPUR is considering taking advantage of the Federal Highway Administration’s Public Lands Highways Grant.
Implementation began in August and September of 2012, when the Golden Gate National Recreation Area (GGNRA) partnered with the San Francisco Public Utilities Commission (SFPUC) to renourish the south end of Ocean Beach with 73,000 cubic yards of sand. The San Francisco Department of Public Works (DPW) is proceeding with the plan to narrow and eventually close the southern portion of the Great Highway (south of Sloat Boulevard). In 2016, DPW is expected to narrow that portion of the highway from four lanes to two by abandoning the two southbound lanes. SPUR also won funding for a coastal management framework and implementation studies from the California State Coastal Conservancy, the San Francisco Public Utilities Commission and the National Park Service. The transportation study includes an existing conditions study, analysis of potential roadway configurations, and traffic flow modeling. An immediate-term management plan developed as part of the framework details interim measures to protect the beach through Spring 2016, including additional beach renourishment and maintenance and enhancement of the existing sandbag structure that helps to stabilize the area. Additional sand that was placed as part of these interim measures provided an important buffer during a major storm in December 2014. The interim plan also established triggers for further action such as removal of the southern portion of the Great Highway, and restoration of a dynamic dune system with native vegetation. The framework also included a detailed engineering feasibility study, completed in August 2015, that provided a coastal management framework for long-term coastal management and protection of the Lake Merced Tunnel, which is a critical piece of SFPUC wastewater treatment infrastructure. Overall, the framework and its studies validated the recommendations initially put forth in the OBMP. It should culminate in an interagency agreement between SFPUC, GGNRA, and the Army Corps to divide adaptive coastal management responsibilities.
The City is proceeding with steps for funding, environmental review, and permitting necessary to carry out the management plan. In Fall 2015, the City received approval from the California Coastal Commission for a package of “soft” coastal protection measures, such as sand placement and sandbags, that can be taken in the interim period over the next six years should they be needed to counteract erosion from winter storms. The permit ensures that the City can act quickly to protect against coastal erosion without first having to obtain reactive emergency permits, while also committing the City to a timetable for obtaining permits for the longer-term measures recommended in the OBMP.
The City also began the process of updating its Local Coastal Program, which is the element of the City’s General Plan that establishes land use, development, and environmental policies for the coastal zone as defined by the California Coastal Commission. This update process will provide an opportunity to incorporate OBMP recommendations into formal policies. The Local Coastal Program must be approved by the Coastal Commission after it is first approved by the San Francisco Planning Commission and Board of Supervisors.
The OBMP was funded by the State of California Coastal Conservancy, the San Francisco Public Utilities Commission, and the National Park Service. Funding was awarded in 2009 at the request of the Ocean Beach Vision Council, a task force appointed by San Francisco Mayor Gavin Newsom.
This Adaptation Clearinghouse entry was prepared with support from the Federal Highway Administration. This entry was last updated on March 9, 2016.
Publication Date: May 21, 2012
- San Francisco Public Utilities Commission
- State of California
- San Francisco Planning and Urban Research Association (SPUR)
- City and County of San Francisco, California
- Case study
- Plans (other)