Friday, April 25, 2014

Save the Bay by Working With Nature not Against It - III

Here is a 14 minute video of a sea wall being overwhelmed by the 2011 Tsunami.  Minute 1 - boring, large seawall, shallow bay.  Minute 2 - water starting to rise but still boring.  Life goes on as normal because everyone feels secure behind the high sea wall.  Skip ahead to minute 5:40 and wait until the 5:57 mark.  Please write in the comment section below if you think a sea wall is desirable for SF Bay.  Click on the lower right corner of the video to enlarge it.

The flooding photos show a cascade of water over a seawall at Miyako which is obviously a bay protected on 3 sides and with a mountainous island clearly in view.  See also:

That is from an earthquake about 43 miles from the Japanese mainland.  Average sea level rise along the Japanese coast was only a few meters, but at Miyako, the waves crested at 124 ft in some places.  "Hayward Fault" anyone?

I lived in a small town just south of Atlantic City for a few years (Margate).  Atlantic City, Margate, and Ventnor all share the same small island which is really just a large sand bar.  All houses were built with a crawl space which raised the first floor of the house about 4 ft above the ground.  Every time a hurricane came by the streets flooded for a few days, which made the evening news, but really caused no substantial harm to anything I could see since every house was built with that in mind.  As a kid I thought it was kind of neat.

So you could build with flooding in mind, pylons driven down, raised floors, sea walls, etc., etc., but the real question is why bother?  A sea wall will cost literally $Billions and to try to protect land which should never have been filled in in the first place.  And it won't even do that when anything substantial happens.  As Steve Sarrette pointed out, if the govt. rewards irresponsible building, it is no longer irresponsible to build there.  Anyone around here not on landfill is probably high enough and on firm enough ground to not need a sea wall so we're really only only talking about new office space which is going to be depreciated over 20 years at the end of which it will be torn down anyway.

The sea wall would be built by every one's taxes to benefit a few developers who could just as easily build anywhere else.  Why would anyone want to pay extra taxes so developers can build on landfill?  There is no shortage of land on the East Bay.  There is lower pop. density in almost every town in the South and East Bay than in Mtn View, Sunnyvale, and Sta, Clara.  Tax $ for a sea wall could instead go to schools, libraries, public transportation, etc., etc.

(see local population densities here:

If you want to do something with the shoreline, plant rice marshes.  It will absorb the impact of waves.  In addition, certain types of rice remove heavy metals like Cadmium and Mercury from the water and soil (called chelation).  The SF Bay is heavily polluted with mercury (hence the "SJ Mercury") from the gold mining days.  A steady removal of that would be a good thing.

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