1. DESIGN VARIATIONS Special Council Meeting May 8, 2017

2. Presentation Topics
Select Flood Protection Scenario for Further Design
FEMA Accreditation Only
FEMA Accreditation Sea Level Rise
FEMA Accreditation Sea Level Rise
Permitting

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

4. 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

5. 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.

6. 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.

7. 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.

8. Resilience to Mid-Century Sea Level Rise

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

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

11. 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)

12. 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.

13. 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.

14. Select Flood Protection Scenario
Project Alternative
Estimated Cost
1. FEMA Accreditation Only1
$60 million
SLR2
$90 million
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.

15. Higher Elevations Have More Immediate Impacts

16. Higher Elevations Have More Immediate Impacts
2050 SLR Project Scenario

17. Higher Elevations Have More Immediate Impacts
2100 SLR Project Scenario

18. 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.

19. Sea Level Rise Predictions – April 26, 2017
Updated sea level rise scenarios were published on April 26, 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 ADAPTATION STRATEGIES BECOME OBSOLETE OVER TIME.
California Ocean Protection Council, Rising Seas in California: An Update on Sea-Level Rise Science, April 2017.

20. 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.

21. 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.

22. 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.

23. 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

24. 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

25. 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

26. 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

27. 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

28. 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 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

29. 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.

30. 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.

31. 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

32. 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.

33. Future Adaptation Cost
Adaptation Strategy Cost Matrix
Adaptation Strategy
Initial Cost
Future Adaptation Cost
Total Cost
High SLR Now
$380 million
SLR and Deep Foundations with Future Addition of Wall Height
$240 million
$150 million
$390 million
SLR with Future Anchor Walls
$130 million
$200 million
$300 million
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.

34. 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.

35. DESIGN VARIATIONS Special Council Meeting May 8, 2017