Erosion and Climate Change Adaptation Projects
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In the 1980’s and 1990’s, in response to the Clean Water Act, the San Francisco Public Utilities Commission (SFPUC) built the Oceanside Treatment Plant
and associated wastewater infrastructure to protect coastal water quality from pollution and protect public health.
As climate change causes sea levels to rise, erosion from storm driven waves is expected to worsen, further threatening coastal infrastructure including roads and sewers, and causing the beach to narrow. Shoreline erosion is threatening the most seaward component of our combined sewer system — the Lake Merced Tunnel (LMT), a fourteen-foot diameter pipe under the Great Highway.
In support of a comprehensive solution to the erosion problem, the SFPUC actively participated in the development of the 2012 Ocean Beach Master Plan (OBMP), an inter-agency effort led by the San Francisco Bay Area Planning and Urban Research Association (SFPUR) to develop a sustainable long-term vision for Ocean Beach. The OBMP addresses and provides a series of recommendations for public access, environmental protection, and infrastructure needs in the context of erosion and climate-related sea level rise.
The SFPUC will develop a comprehensive shoreline management and protection plan against bluff erosion and climate-change induced sea level rise along Ocean Beach south of Sloat Boulevard consistent with the recommendations in the OBMP. This is necessary to protect the integrity of wastewater assets built to protect public health and the environment, including the Lake Merced Tunnel (LMT), the Westside Pump Station and the Oceanside Treatment Plant.
Short Term Improvements
Ongoing efforts continue to be implemented to provide interim protection and improved beach access while the SFPUC develops the Climate Adaptation Project. As part of the agreement with the California Coastal Commission, the SFPUC monitors SOB throughout the year to help determine threats to the infrastructure and inform the sand replenishment activities. The SFPUC with partners including the National Park Service (NPS), U.S. Army Corps of Engineers, SF Rec and Parks and SF Public Works, perform beach nourishment (e.g. sand backpassing), sandbags placement, and debris removal, as needed along the southern portion of Ocean Beach fronting the Great Highway. These measures will protect the LMT and associated critical infrastructure from exposure due to erosion until the City implements the Climate Adaptation Project and Long-Term Improvements.
Status of Beach Nourishment
- Since 2016, over 160,000 cubic yards of sand have been transported from the northern portion of Ocean Beach where sand is plentiful to the area south of Sloat Boulevard most susceptible to wave-driven erosion.
- SFPUC hired a new contractor in the Spring of 2018 to perform the sand backpass. They will implement coastal protection actions as needed for three years.
- The monitoring throughout the Winter 2018-2019 determined that a backpass event is required in the Fall of 2019 to re-establish the sacrificial sand berms and cover the sand bags. The SFPUC will continued monitoring to comply with our permit requirements
- The U.S. Army Corps of Engineers is reviewing the Design Agreement for Section 204 Beneficial Reuse of dredged sand at Ocean Beach south of Sloat Boulevard. The timing for completion of the design and availability for use of the sand is unknown at this time. The beneficial reuse of dredged sand will be implemented as part of the long-term coastal management strategy.
Progress and Status
The Ocean Beach Long-Term Improvements Project is the result of extensive planning captured in the Alternatives Analysis Report. This project is expected to involve the implementation of coastal management strategies that include managed retreat (i.e., re-contouring the bluffs and removing the Great Highway between Sloat and Highway 35), removal of rubble from the beach and bluffs, continued beach nourishment, and installation of a low-profile wall to protect the Lake Merced Tunnel. This project will not only protect vital public wastewater infrastructure, but will also improve access, recreation, and habitat at South Ocean Beach.
- An Engineering Contract received Notice of Contract Award on September 27, 2018.
- An Environmental Consultant Contract received Notice of Contract Award on August 18, 2018.
- The Ocean Beach Long-Term Improvements Project is expected to begin construction in 2022.
Rendering of the Lake Merced Tunnel with a low-profile underground wall providing protection.