Olympia City Council Study Session 11.15.2011: Sea Level Rise

I was unable to attend the city council study session this week on Sea Level Rise, but the staff report contains some noteworthy information. Hopefully some of you who did attend can comment and fill the rest of us in.

First let’s summarize this study in a larger context. From the staff report:

In October 2010, City Council adopted near-term sea rise policies and management policies:

1.       The City is committed to protecting downtown from the impacts of sea level rise. 

2.       The City will seek to understand the implications of and planning for a potential 100-year sea rise of 50 inches. Decisions regarding downtown Olympia embody high financial value, high potential risk, and long-time horizons. These traits of downtown warrant a cautious approach to sea level rise planning.

3.       Incorporate adaptation and flexibility into both public and private infrastructure projects. Use design opportunities for new public and private investments to prepare for sea rise.

4.       Seek opportunities to maintain control of valuable shoreline. With respect to managing sea rise and potential flooding, our urban shoreline is a highly valuable resource.

Pursuant to these management policies, the city’s Public Works Department has been conducting engineering, and other relevant studies so that it is able to formulate more direct management policies. Using computer simulations, they are examining several natural “interactions” and how those would affect the downtown areas, including high tides, Moxlie/Indian Creek overflows, runoff, etc. This is obviously more detailed and technical than I have the competency to explain, but luckily the staff report contains a summary of key findings which they say has given them a “sound technical basis for the future”. Here are their pretty bleak but still intermediary conclusions:

  • Downtown is more vulnerable to tidal flooding under current conditions than we anticipated.
  • Our analysis highlights greater flooding risks in downtown than depicted in the 1983/2003 Federal flood risks maps.
  • Understanding the current risks, improving emergency response procedures is important in the near-term.
  • Given the current flood risk and flat topography of downtown, minimal sea rise (0.25 feet) could appreciably exacerbate the risk.
  • Existing essential transportation corridors and emergency services located in downtown led us, at least in this analysis, to develop strategies that protect the entirety of the downtown and Port peninsula.
  • Fortunately, the majority of the downtown shoreline is in public ownership. Ongoing shoreline redevelopment projects (e.g., Percival Landing) are incorporating protection measures.
  • Long-term costs of sea barriers and pumps are high.
  • Initial response strategies are straightforward and can be implemented in the near–term.

Bad news: it’s worse than initially thought and costs will be high. Good news: there appear to be near-term responses that the city can implement.

I’ll leave it to you to visit the staff report and examine the next steps on Page 4.

So who attended the study session and what did you learn?

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