Note: This is from the Agenda Packet for the March 28, 2023, Joint Study Session on Sea Level Rise. It is presented as it was delivered in the packet. Any notes not in the original are surrounded by square brackets.

For further information on this meeting and to watch the video, see “Sea Level Rise presentation to Council and PlanCom — Tuesday, March 28th.“
For more articles on Arcata1.com about Sea Level Rise, click here — or do a search for Sea Level Rise.

Sea Level Panel Discussion
March 28, 2023

Purpose – The purpose of the SLR Study Session is to provide the City Council, the Planning Commission, and the community information from four experts’ perspectives to inform their policy decisions, balancing future climate risk with current and future social and community needs.

Objectives – The Commission and Council will develop a better understanding about sea level rise risk and the factors to consider when balancing policy options for future growth and development of the City.

Outcomes – Decision makers will get answers from national, state, and local experts to their sea level rise questions; and decision makers will have more information to make policy decisions on the Local Coastal Program, the General Plan, and various zoning ordinances.

Meeting Outline

Prepared Questions

1. It seems like the projections for SLR keep getting worse, and new projections land beyond worst case for previous projections. Given this, how do we assess the various projections? How far into the future are the projections reasonably accurate?

2. In the Ocean Protection Council’s report, the extreme risk aversion scenario projects 15 feet of sea level rise by 2120. Why does NOAA’s new guidance recommend dropping the H++ extreme risk aversion scenario for planning purposes?

3. Do the current mapped areas of sea level risk vulnerability take into consideration existing dikes, levies, roads or other infrastructure? 
[misspelled “levies” – should be “levees”]

4. What about infrastructure that may be developed in the future? Given the City’s location,
geography, and geology, is “armoring”, including eco-levies, living shoreline, and other
infrastructure solutions, a feasible response to six feet of sea level rise? How about 10 feet?
[misspelled “levies” – should be “levees”]

5. How are different tide and storm events considered in the models? How might these events influence factors on the ground?

6. How should we be planning for the interaction between extreme sea level rise, large storm events (100-yr or 500-yr, say), and tsunami? Are there are differences in the scale, probability, correlation, or scope that should be considered when doing urban planning, hazard/emergency response planning, or adaptation planning?

7. Of the various scenarios, which is most appropriate for planning purposes? Please let us know why? How does this change for different use types? Residential, commercial, critical
infrastructure?

8. Lastly, the City’s current adaptation strategy considers a range of environmental, fiscal, and social factors. Retreat will be prioritized in areas that have low-risk, lower investment assets, such as grazed low-lying lands, that do not have a significant impact on the community. Areas, such as South G Street, which has significant public and private investments, a concentration of lower-income households, high rates of home ownership, dozens of businesses, and high-value community assets, such as the marsh a wildlife sanctuary, will be prioritized for adaption designed to preserve these areas as long as it is cost feasible. These areas would receive priority for living shorelines, new levees, and stormwater management systems designed to buffer tidal flooding impacts. What are your thoughts on this strategy?