A word of support for Bob Harper’s view published on April 14, “Why not build a tunnel?” Yes, we already have “Bertha” paid for; just put it on a barge and bring it down for the Columbia Crossing Tunnel. Harper has excellent ideas about the points of entrances, and this would allow continued use of the existing bridge with minimal displacement of people and properties.
I know that the area the tunnel would go through is mostly sedimentary material, down to 300 feet or more. The Seattle tunnel was dug to a depth of 150 feet below sea level. There are some existing core samples of the area to cross and further ones can easily be done to confirm the possibility of creating the tunnel project.
Please contact and support your representatives about this idea. A number of planning sessions are coming up; please take a minute and present your thoughts.