Port of San Diego installing more than 300 “reef balls” to help protect South Bay from rising sea levels

The Port of San Diego, in partnership with the California State Coastal Conservancy and U.S. Fish & Wildlife Service, has begun installation of the South Bay Native Oyster Living Shoreline Project adjacent to the Chula Vista Wildlife Refuge. This project has been years in the making and is the latest of several Port projects to protect the shoreline from impacts related to rising sea levels and to increase the biodiversity of San Diego Bay by creating new marine habitats.

The project’s total cost is approximately $960,000 and is fully funded via grants from the U.S. Fish and Wildlife Service and Builders Initiative. The cost covers the fabrication, installation, and long-term monitoring of the project.

Living shorelines rely on natural elements, such as plants or, in this case, oysters, to stabilize shorelines in place of the traditional hard armoring – such as rip rap revetment and sea walls that we currently see prevalent around the bay. Living shorelines are an excellent resiliency strategy in the face of sea level rise due to their ability to naturally adapt and grow over time.

This project is utilizing a modular approach under which constructed reef ball elements are being placed in a series of six arrays. Each reef array includes 15 reef groups composed of four reef ball elements made of baycrete (concrete mixed with local sand and oyster shell aggregate) placed in a square pattern for a total of 360 reef ball elements and 90 reef groups. The elements will be placed at specific elevations to optimize recruitment of native oysters.

Each reef array is roughly 88 feet long by 45 feet wide to accommodate the 15 reef groups with 14-20 feet of spacing between each reef group. While the total area of the project spans approximately 29,700 sf (0.68 acre) of intertidal shoreline, the total "footprint" of the reef ball elements would be substantially lower at 5,760 sq ft (0.13 acre).

The project’s objective is to demonstrate the ability to attract and establish native oyster populations that create structurally complex "reef" habitats for fish, birds, invertebrates, and aquatic plants. The project is also expected to improve local water quality via oyster water filtration and settling of sediments, as well as increase wetland connectivity to intertidal and subtidal lands.

After installation is complete, the pilot project and the adjacent shoreline will be monitored and assessed for five years to study the amount of growth of native oysters on the reef elements; learn about the presence and/or absence of non-native species on the reef elements; learn how the reef impacts or enhances local species richness of fish, birds and mobile invertebrates within the project footprint; and determine the ability of the reef elements to catalyze sediment accretion or reduce erosion of sediment shoreward of the project.

The project is the result of over five years of collaboration across a project team representing state and federal agencies, academia, regional government, and the non-profit sector, including Environmental Science Associates who were involved in the design process. If successful, the reef will be permanent. Project partners share an interest in addressing shoreline protection, fishery populations and health, and climate change in San Diego Bay through scientifically supported alternatives to standard shoreline armoring.

ABOUT THE PORT OF SAN DIEGO
The Port of San Diego serves the people of California as a specially created district, balancing multiple uses on 34 miles along San Diego Bay spanning five cities. Collecting no tax dollars, the Port manages a diverse portfolio to generate revenues that support vital public services and amenities.

The Port champions Maritime, Waterfront Development, Public Safety, Experiences and Environment, all focused on enriching the relationship people and businesses have with our dynamic waterfront. From cargo and cruise terminals to hotels and restaurants, from marinas to museums, from 22 public parks to countless events, the Port contributes to the region’s prosperity and remarkable way of life on a daily basis.

ABOUT PORT OF SAN DIEGO ENVIRONMENT
Port of San Diego Environment champions the safekeeping and environmental care of our diverse ecosystems. Year after year, environmental goals are set and measured to evolve environmental initiatives – ensuring San Diego Bay remains a vibrant resource and contributes to a remarkable way of life for visitors and residents for generations to come.