After months of planning and a one week delay, the E-3 pier of the old Bay Bridge is set to be imploded tomorrow morning between 6:45 and 7 a.m. But a brown pelican or a least tern in the area could delay the action again, says a San Francisco Chronicle report. According to that article, 20,000 pounds of dynamite will be used to take down the largest remaining pier from the old bridge. The blast will last six seconds, and most of the resulting rubble will be entombed in the base of the old pier. A wood-and-steel mat and an underwater "bubble curtain" of air will also corral flying debris. Caltrans officials told the Chronicle they will be using noise-generating buoys to keep marine life at bay, but an animal or a bird coming in too close at the last minute will temporarily halt the process. Some of the fish won't be so lucky.
Caltrans officials told the Chronicle that a pressure wave after the blast could kill as many as 1,775 endangered longfin smelt, and perhaps other fish. But the agency adds that it's the lesser of two evils, given that taking the pier out by machine could take as long as four years and potentially kill more wildlife.
Here's what it means for the humans: Traffic going in both directions will be halted for 15 minutes before the scheduled blast. BART service will also be halted for a short time. The new bridge's bike and pedestrian path will be closed starting tonight and boats will be kept back at least 1,500 feet from the pier during the morning event. If you want an up-close look, Caltrans spokespeople say to search for "E3 implosion" on YouTube, as they have set up cameras on a nearby pier and underwater to record the action.
As we reported earlier, if all goes as planned, 12 more small piers could be demolished in the same way.
· Caltrans aims for early Saturday on old Bay Bridge pier blast [SFGate]
· Hold Up: Implosion of the Old Bay Bridge Pier Delayed A Week [Curbed SF]