Port of San Francisco's Multi-Hazard Risk Assessment

About the Multi-Hazard Risk Assessment

The Multi-Hazard Risk Assessment, or MHRA, provides a comprehensive understanding of existing earthquake and flood risks along the Embarcadero and establishes a basis for the development of Proposition A projects.

Findings from the MHRA are key to understanding which areas of San Francisco’s Embarcadero waterfront are most at risk, the likely consequences, and what areas the Port needs to focus on first. By understanding the potential consequences of earthquakes, Port staff, policymakers, and the public will be able to make better decisions on where first Proposition A bond investments should be made. The priorities for the first projects and bond funds are to improve life safety and disaster response.

Based on findings from the MHRA and stakeholder engagement work, Port staff are formulating project options, called alternatives – incorporating both seismic and flood risk reduction whenever possible – for the Embarcadero Seawall Program with a focus on identifying the Proposition A projects for Port Commission approval by the end of March 2021.


Learn more about the MHRA through this short "Explainer" video:










How Does the MHRA Advance our Understanding Since 2016?

In addition to helping the Port develop important tools and strengthen key partnerships, the MHRA significantly advanced the Port’s understanding of the risks and consequences associated with earthquake and flood risk along the Embarcadero waterfront.


For example, we now know:

Soil conditions have a big effect, creating higher and lower risk zones.

Deep Young Bay Mud is a problem in some areas and sand layers are a problem in other locations, while ground shaking and settlement are Embarcadero-wide problems.


Earthquake risk to San Francisco’s waterfront is severe and the consequences will be expensive.

Through the MHRA, we now have predictions of physical damages and understand economic losses across four earthquake levels (minimal, moderate, high, and severe). Included in the economic loss predictions are cost of repair/replacement, loss of building-related contents, business interruption and relocation, lost wages, lost rent to the Port, and indirect and induced effects. These estimates allow us to quantify the fiscal benefits of investment.


San Francisco’s waterfront is very sensitive to flood thresholds, with significant consequences.

We now have predicted coastal flood damages for all buildings and major infrastructure exposed by Seawall “overtopping,” which is when water, usually in the form of storm surge or a wave, reaches over the shoreline and causes inland flooding. We also have the first flood-mapping of the City that includes wave action, an important contributor to flooding.


In addition, we now understand the specific consequences of earthquake-and flood-related damages to: disaster response systems (earthquake only), utilities, transportation, historic districts and resources, public spaces, maritime industries, land use, and environmental assets. This understanding will allow the Port to prioritize available investment in the areas where it will provide the greatest benefit (including emergency response and life safety).









Key Earthquake and Flood Findings for San Francisco’s Embarcadero Waterfront

MHRA results are helping the Port and the City better predict the extent and likelihood of shoreline stability along the Embarcadero, or which buildings and infrastructure are expected to be safe from hazards. For more information on MHRA results by specific waterfront location, please visit the Waterfront Resilience Story Maps.


We now know:

The area around the Ferry Building is one of the highest risk areas on the waterfront from both earthquakes and flooding.

The subarea has some of the lowest elevations along the Embarcadero Seawall and includes areas of the shoreline that are currently overtopped by Bay waters during storm events and extreme tidal events. Additionally, the subarea’s location within historic Yerba Buena Cove results in significant risk from earthquakes due to the very deep Bay mud in this area. Further seismic analysis is required to better understand the impacts to the Ferry Building itself in various earthquake scenarios.


Many historic buildings and bulkhead wharves are at high risk.

The bulkhead wharves are the structures located where the pile supported piers over the Bay meet the land. These structures are interconnected with the Seawall and support the ornate, historic bulkhead buildings that line the Embarcadero. These structures are at high risk of earthquake damage and will flood with increasing sea levels.


In the South Beach subarea, earthquake instability of the Seawall is lower than previously thought.

Lateral spreading and Seawall movement is not expected to be a problem in the area, but strong ground shaking is expected to damage wharves and the roadway.


Wood pile-supported structures in Fisherman’s Wharf are vulnerable to both ground shaking and lateral spreading.

Port staff will use MHRA results to brief Port tenants about seismic and flood risks and discuss opportunities for making these facilities safer. In addition, Fisherman’s Wharf was consistently identified as an important area through community engagement.









Embarcadero Seawall Program Next Steps

The MHRA is a key component of the decision making process. However, much work is still to come. The MHRA evaluates the risk and costs but not the measures that can be taken to reduce these risks. The MHRA also does not look beyond risk to the possible benefits that can improve the waterfront, such as strengthening disaster response capabilities or creating more open space.


Following completion of the MHRA, the Port is developing strategies and solutions to reduce risk. The Port’s goal is to identify the measures that are most appropriate to protect the many different conditions along the waterfront in ways that reflect city and community priorities, combining seismic and flood risk improvements wherever feasible and cost-effective. Learn more about measures under consideration via the Port’s Measures Explorer.

Proposition A bond-funded projects will be selected in March 2021.


Resources

About the Multi-Hazard Risk Assessment

The Multi-Hazard Risk Assessment, or MHRA, provides a comprehensive understanding of existing earthquake and flood risks along the Embarcadero and establishes a basis for the development of Proposition A projects.

Findings from the MHRA are key to understanding which areas of San Francisco’s Embarcadero waterfront are most at risk, the likely consequences, and what areas the Port needs to focus on first. By understanding the potential consequences of earthquakes, Port staff, policymakers, and the public will be able to make better decisions on where first Proposition A bond investments should be made. The priorities for the first projects and bond funds are to improve life safety and disaster response.

Based on findings from the MHRA and stakeholder engagement work, Port staff are formulating project options, called alternatives – incorporating both seismic and flood risk reduction whenever possible – for the Embarcadero Seawall Program with a focus on identifying the Proposition A projects for Port Commission approval by the end of March 2021.


Learn more about the MHRA through this short "Explainer" video:










How Does the MHRA Advance our Understanding Since 2016?

In addition to helping the Port develop important tools and strengthen key partnerships, the MHRA significantly advanced the Port’s understanding of the risks and consequences associated with earthquake and flood risk along the Embarcadero waterfront.


For example, we now know:

Soil conditions have a big effect, creating higher and lower risk zones.

Deep Young Bay Mud is a problem in some areas and sand layers are a problem in other locations, while ground shaking and settlement are Embarcadero-wide problems.


Earthquake risk to San Francisco’s waterfront is severe and the consequences will be expensive.

Through the MHRA, we now have predictions of physical damages and understand economic losses across four earthquake levels (minimal, moderate, high, and severe). Included in the economic loss predictions are cost of repair/replacement, loss of building-related contents, business interruption and relocation, lost wages, lost rent to the Port, and indirect and induced effects. These estimates allow us to quantify the fiscal benefits of investment.


San Francisco’s waterfront is very sensitive to flood thresholds, with significant consequences.

We now have predicted coastal flood damages for all buildings and major infrastructure exposed by Seawall “overtopping,” which is when water, usually in the form of storm surge or a wave, reaches over the shoreline and causes inland flooding. We also have the first flood-mapping of the City that includes wave action, an important contributor to flooding.


In addition, we now understand the specific consequences of earthquake-and flood-related damages to: disaster response systems (earthquake only), utilities, transportation, historic districts and resources, public spaces, maritime industries, land use, and environmental assets. This understanding will allow the Port to prioritize available investment in the areas where it will provide the greatest benefit (including emergency response and life safety).









Key Earthquake and Flood Findings for San Francisco’s Embarcadero Waterfront

MHRA results are helping the Port and the City better predict the extent and likelihood of shoreline stability along the Embarcadero, or which buildings and infrastructure are expected to be safe from hazards. For more information on MHRA results by specific waterfront location, please visit the Waterfront Resilience Story Maps.


We now know:

The area around the Ferry Building is one of the highest risk areas on the waterfront from both earthquakes and flooding.

The subarea has some of the lowest elevations along the Embarcadero Seawall and includes areas of the shoreline that are currently overtopped by Bay waters during storm events and extreme tidal events. Additionally, the subarea’s location within historic Yerba Buena Cove results in significant risk from earthquakes due to the very deep Bay mud in this area. Further seismic analysis is required to better understand the impacts to the Ferry Building itself in various earthquake scenarios.


Many historic buildings and bulkhead wharves are at high risk.

The bulkhead wharves are the structures located where the pile supported piers over the Bay meet the land. These structures are interconnected with the Seawall and support the ornate, historic bulkhead buildings that line the Embarcadero. These structures are at high risk of earthquake damage and will flood with increasing sea levels.


In the South Beach subarea, earthquake instability of the Seawall is lower than previously thought.

Lateral spreading and Seawall movement is not expected to be a problem in the area, but strong ground shaking is expected to damage wharves and the roadway.


Wood pile-supported structures in Fisherman’s Wharf are vulnerable to both ground shaking and lateral spreading.

Port staff will use MHRA results to brief Port tenants about seismic and flood risks and discuss opportunities for making these facilities safer. In addition, Fisherman’s Wharf was consistently identified as an important area through community engagement.









Embarcadero Seawall Program Next Steps

The MHRA is a key component of the decision making process. However, much work is still to come. The MHRA evaluates the risk and costs but not the measures that can be taken to reduce these risks. The MHRA also does not look beyond risk to the possible benefits that can improve the waterfront, such as strengthening disaster response capabilities or creating more open space.


Following completion of the MHRA, the Port is developing strategies and solutions to reduce risk. The Port’s goal is to identify the measures that are most appropriate to protect the many different conditions along the waterfront in ways that reflect city and community priorities, combining seismic and flood risk improvements wherever feasible and cost-effective. Learn more about measures under consideration via the Port’s Measures Explorer.

Proposition A bond-funded projects will be selected in March 2021.


Resources