The Navy began embedding a steel barrier along several hundred feet of the western shoreline of Alameda Point during the week of August 18. The purpose of the barrier is to contain contaminated ash and burn waste material that was bulldozed into the Bay some 60 years ago and is now overlain with silt. The area is where the Navy burned various waste materials.
The containment system is called a waste isolation barrier. It consists of 35-foot-long interlocking steel pilings that are hammered into the ground with a hydraulic vibrator suspended from a crane cable. Perpendicular steel walls behind the barrier add stability. The final elevation of the top of the waste isolation barrier will be approximately 10 feet above mean sea level.
Tests around the area were conducted in 2010, 2011, and 2012 to determine if any of the chemicals in the burn residue were entering San Francisco Bay. None were found to be entering the Bay. Nevertheless, the Burn Area’s proximity to the Bay requires that the contaminated waste either be removed or permanently isolated. Removing all of the waste from under the shoreline would have cost $40 million. The containment system costs $13 million.
The construction of the shoreline waste barrier is part of a larger Navy cleanup project on the adjacent 37 acres, called Site 1, which was once used as an underground waste disposal area. Much of the area is now covered by runway pavement that will remain in place. The entire 37 acres right up to the steel barrier will be covered with three feet of clean soil and seeded with native vegetation. A small wetland area will also be created along the shoreline.
When completed early next year, the area will be suitable for passive recreational use, including the Bay Trail.
The work can be observed from the Oakland side of the estuary at Middle Harbor Shoreline Park right next to the cranes.
Originally published in the Alameda Sun.
Background information can be found in this post from April 2013.
More photos and a diagram below