DESIGN VARIATIONS Special Council Meeting May 8, 2017

Presentation Topics Select Flood Protection Scenario for Further Design FEMA Accreditation Only FEMA Accreditation + 2050 Sea Level Rise FEMA Accreditation + 2100 Sea Level Rise Permitting

Freeboard Deficiencies Providing FEMA Freeboard for Accreditation FEMA Required Elevations Existing Levee Elevations Freeboard Deficiencies

Flood Protection Scenario Feasibility Levee improvement project requires numerous permits The State recognizes that Sea Level Rise (SLR) is a significant threat BCDC requires resilience through design to the high range of 2050 SLR Both RWQCB and BCDC require risk assessments and adaptation strategies to address 2100 SLR

Sea Level Rise Predictions Adaptively raising levees for future sea level rise is a policy decision that will affect project design. Permit agencies are now asking for resilience to high range 2050 SLR and adaptability to high range 2100 SLR. 2012 SLR Curves Time Period Projection (inches) Range CEQA Project Description 2000 – 2030 6±2 2 to 12 --- 2000 – 2050 11±4 5 to 24 15 2000 – 2100 36±10 17 to 66 46 Note that guidelines published by BCDC in November 2016 suggest that all [significant] projects should be designed to be resilient to a mid-century sea level rise projection. The Bay Plan policies on Climate Change state, in part, that: “If it is likely the project will remain in place longer than mid-century, an adaptive management plan should be developed to address the long-term impacts that will arise based on a risk assessment using the best available science-based projection for sea level rise at the end of the century.” We have been verbally told in meetings that they will interpret these guidelines to mean high range SLR estimates, whereas we previously based the designs on estimates of “likely” rise plus one standard deviation.

Sea Level Rise Predictions Of interest. Not much SLR since 2000, so we aren’t worried about making adjustments to what FEMA has or what we have been doing. Year 2000 remains a valid index for SLR predictions.

Select Flood Protection Scenario Flood Protection Scenarios FEMA Freeboard (FEMA) FEMA Freeboard + 15” Sea Level Rise for 2050 (2050 SLR) FEMA Freeboard + 46” Sea Level Rise for 2100 (2100 SLR) The 2050 SLR and 2100 SLR scenarios were analyzed in the EIR at an equal level of detail. The FEMA scenario was analyzed as a project alternative. A project scenario is considered feasible if we have confidence that it can be permitted, financed and built.

Resilience to Mid-Century Sea Level Rise

Resilience to Mid-Century Sea Level Rise 2022 (NO)

Resilience to Mid-Century Sea Level Rise 2022 (NO) 2050 (YES)

Resilience to Mid-Century Sea Level Rise Note that 2100 design falls short of resilience to high range 2100 SLR by nearly 2 feet. 2022 (NO) 2050 (YES) 2085 (YES)

Select Flood Protection Scenario Flood Protection Scenarios FEMA Freeboard (FEMA) FEMA Freeboard + 15” Sea Level Rise for 2050 (2050 SLR) FEMA Freeboard + 46” Sea Level Rise for 2100 (2100 SLR) The 2050 SLR and 2100 SLR scenarios were analyzed in the EIR at an equal level of detail. The FEMA scenario was analyzed as a project alternative. A project scenario is considered feasible if we have confidence that it can be permitted, financed and built.

Select Flood Protection Scenario Flood Protection Scenarios FEMA Freeboard (FEMA) FEMA Freeboard + 15” Sea Level Rise for 2050 (2050 SLR) FEMA Freeboard + 46” Sea Level Rise for 2100 (2100 SLR) The 2050 SLR and 2100 SLR scenarios were analyzed in the EIR at an equal level of detail. The FEMA scenario was analyzed as a project alternative. A project scenario is considered feasible if we have confidence that it can be permitted, financed and built.

Select Flood Protection Scenario Project Alternative Estimated Cost 1. FEMA Accreditation Only1 $60 million 2. 2050 SLR2 $90 million 3. 2100 SLR3 $170 million Does not meet regulatory requirements for permitting. Assumes 80-year life. Based on projection of future SLR. May require additional future adaptation.

Higher Elevations Have More Immediate Impacts

Higher Elevations Have More Immediate Impacts 2050 SLR Project Scenario

Higher Elevations Have More Immediate Impacts 2100 SLR Project Scenario

Future Sea Level Rise Adaptation Strategies Permitting Future Sea Level Rise Adaptation Strategies Build another project in the future if and when it is needed Build a project designed for 2100 high range SLR now Adapt to rising sea level over time Foundation depth for 2100 SLR now; add wall height later Future anchor walls Future offshore solutions We need to propose an adaptation plan for regulatory approval and there are options, but those options should be something the City could live with. Also we may need to incorporate certain features into the project now to facilitate the adaptation options. Note that future adaptation work will require its own environmental documentation at the time of implementation, and none of the adaptation plan alternatives identified to date and discussed tonight require revisions to the Final EIR for the initial project.

Sea Level Rise Predictions – April 26, 2017 Updated sea level rise scenarios were published on April 26, 2017. It is not clear yet how BCDC and other regulatory agencies might adopt these new estimates. Note that the most significant change is an added scenario (curve) titled “Extreme”, which is labeled as the H++ scenario. The H++ scenario represents an unknown probability, high consequence scenario such as would occur if high rates of Antarctic ice loss were to develop in the last half of this century. “These sea-level rise projections will continue to change as scientific understanding increases and as the impacts of local, state, national and global policy choices become manifest.” So we need to do our best to balance initial and future expenditures and impacts in the face of such uncertainty. ALSO NOTE THAT THE CURVES JUST DON’T LEVEL OFF AT 2100. ADAPTATION STRATEGIES BECOME OBSOLETE OVER TIME. California Ocean Protection Council, Rising Seas in California: An Update on Sea-Level Rise Science, April 2017.

Sea Level Rise Predictions – April 26, 2017 Year Projection Published in 2012 (feet) Project Flood Protection Scenarios 67% Confident “Likely” 95% Confident 99.5% Confident Extreme “H++” 2030 0.5 --- 0.3 – 0.5 0.6 0.8 2050 0.9 1.3 0.6 – 1.1 1.4 1.9 2100 3.0 3.8 1.6 – 3.4 4.4 6.9 10.0 2150 2.8 – 5.8 7.7 13.0 22.0 The latest SLR projections are less than two weeks old and we have not vetted their implications with BCDC or other regulatory agencies. 2017 SLR estimates presented in the table reflect the RCP 8.5 Scenario, which is consistent with a future in which there are no significant global efforts to limit or reduce emissions.

Sea Level Rise Predictions – April 26, 2017 Year Projection Published in 2012 (feet) Project Flood Protection Scenarios 67% Confident “Likely” 95% Confident 99.5% Confident Extreme “H++” 2030 0.5 --- 0.3 – 0.5 0.6 0.8 2050 0.9 1.3 0.6 – 1.1 1.4 1.9 2100 3.0 3.8 1.6 – 3.4 4.4 6.9 10.0 2150 2.8 – 5.8 7.7 13.0 22.0 We can note that even based on the latest projections, the 2050 SLR Project Scenario remains resilient through 2050 with a 99.5 percent level of confidence. This represents nearly 3 standard deviations (99.7% confidence) or what is sometimes referred to as “near certainty”. To date, adaptation plan formulation, which we are working through the permitting process, has used a high range 2100 SLR projection of 5.5 feet. We will need to work with the regulatory agencies to formulate the appropriate level of confidence in our adaptation plan. The next few slides of this presentation will focus on alternative adaptation strategies with 3 sigma confidence. 2017 SLR estimates presented in the table reflect the RCP 8.5 Scenario, which is consistent with a future in which there are no significant global efforts to limit or reduce emissions.

Sea Level Rise Predictions – April 26, 2017 Year Projection Published in 2012 (feet) Project Flood Protection Scenarios 67% Confident “Likely” 95% Confident 99.5% Confident Extreme “H++” 2030 0.5 --- 0.3 – 0.5 0.6 0.8 2050 0.9 1.3 0.6 – 1.1 1.4 1.9 2100 3.0 3.8 1.6 – 3.4 4.4 6.9 10.0 2150 2.8 – 5.8 7.7 13.0 22.0 It is not considered feasible to actively plan infrastructure for the extreme SLR scenario at this time. What might our upcoming discussions with the regulatory agencies entail? Let’s look at some options. 2017 SLR estimates presented in the table reflect the RCP 8.5 Scenario, which is consistent with a future in which there are no significant global efforts to limit or reduce emissions.

Adaptation Strategy No. 1 – Build for 2100 High SLR Now Initial (and Final) Construction $380 million 2100 High SLR elevation 3 ft 9 feet 5 feet Beach Park Blvd. Foundation depth for 2100 High SLR

Initial Construction $240 million Adaptation Strategy No. 2 – Build to 2050 SLR and foundation depth for 2100 High SLR to allow future adaptation by adding wall height Initial Construction $240 million 2050 SLR Design Elevation 3 ft 3 feet 5 feet Foundation depth for 2100 High SLR

Adaptation Strategy No. 2 – Future Additional Wall Height Adaptive Construction in Future $150 million Add fill Add to walls for 2100 High SLR Elevation 3 ft 6 ft

Initial Construction $130 million Adaptation Strategy No. 3 – Build to 2050 SLR and foundation depth for 2100 High SLR to allow future adaptation for a secondary wall anchor Initial Construction $130 million 2050 SLR Design Elevation 3 ft Foundation depth for 2100 High SLR assuming future anchor wall

Adaptation Strategy No. 3 – Future Secondary Wall Anchor Adaptive Construction in Future $200 million Add wall height for 2100 High SLR Elevation 3 ft Add secondary sheet pile wall anchor

Initial Construction $90 million Adaptation Strategy No. 4 – Build to 2050 SLR and foundation depth for 2100 High SLR to allow future adaptation using offsore features Initial Construction $90 million 2050 SLR Design Elevation is also 2100 High SLR stillwater + 1.7 feet 3 ft How do we get rid of the waves? Foundation depth for 2050 SLR with waves is same as foundation depth for 2100 High SLR back levee without waves

Adaptation Strategy No. 4 – Future Offshore Features Adaptive Construction in Future $100 million Adaptively build up offshore breakwater and beach forms 3 ft Ultimately the sheet pile is no longer needed structurally as the inert earthen forms resist loading. The steel can start to rot away after 2100 with no ill effects.

Adaptation Strategy No. 4 Source: NOAA The green-gray spectrum of coastal flood protection. We will start gray (revetment and bulkhead) and eventually become more green in areas of high wave action. The most feasible way to eliminate the high wave energy along the open Bay portion of Foster City is to eventually construct a breakwater, which could encourage sediment accretion behind it. We could also actively place material behind the breakwater in the future. Note that the greenest/softer techniques are suitable for most areas EXCEPT HIGH WAVE ENERGY ENVIRONMENTS.

Adaptation Strategy No. 4 Why don’t we pursue constructing a living shoreline (LS) now? Reminder: FEMA Region IX has not approved a Living Shoreline for Levee Accreditation Source: California Coastal Conservancy

Adaptation Strategy No. 4 Note that offshore structures are not needed, nor are effective, in dampening wave activity within the sheltered Belmont Slough, so other forms of adaptation are required. Either deeper pile installation or future anchor walls.

Future Adaptation Cost Adaptation Strategy Cost Matrix Adaptation Strategy Initial Cost Future Adaptation Cost Total Cost 1. 2100 High SLR Now $380 million 2. 2050 SLR and Deep Foundations with Future Addition of Wall Height $240 million $150 million $390 million 3. 2050 SLR with Future Anchor Walls $130 million $200 million $300 million 4. 2050 SLR with Future Offshore Adaptation $90 million $100 million $190 million All listed strategies are initially resilient to 2050 sea level rise and adaptable to 2100 SLR with 99.5% confidence.

Project Recommendation Project Alternative Initial Cost Future Cost 2050 SLR Flood Protection Scenario + Future Offshore Features Adaptation Strategy for Permitting $90 million $100 million Assumes 80-year project life. Meets regulatory requirements for permitting. Future estimated cost of $100 million is based on offshore improvements with anticipated sea level rise. Costs may vary.

DESIGN VARIATIONS Special Council Meeting May 8, 2017