Shoreline contamination barrier under construction at NW tip of Alameda Point

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.

Three of the waste isolation cells under construction at northwestern tip of Alameda Point.  A total of 15  cells, each one separated by a wall behind the face of the barrier, will be constructed here.
Three of the waste isolation cells under construction at northwestern tip of Alameda Point. A total of 15 cells, each one separated by a wall behind the face of the barrier, will be constructed here.

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.

A worker guides one of the galvanized steel pilings into place as crane operator maneuvers.
A worker guides one of the galvanized steel pilings into place as crane operator maneuvers.

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.

Piling being slowly driven into the ground by a hydraulically operated vibratory hammer.
Piling being slowly driven into the ground by a hydraulically operated vibratory hammer.

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.

Site 1 cleanup project with crane.  Oakland Estuary in the foreground and San Francisco in the background.
Site 1 cleanup project with crane. Oakland Estuary in the foreground and San Francisco in the background.

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 

Waste isolation barrier, looking east

Interlocking pilings closeup

Waste isolation barrier will have 12 more cells to the right when completed.
Waste isolation barrier will have 12 more cells to the right when completed.
Diagram of shoreline waste isolation barrier at northwestern tip of Alameda Point.  Navy diagram.
Diagram of shoreline waste isolation barrier at northwestern tip of Alameda Point. Navy diagram.

Site 1 waste isolation barrier under construction

Author: richard94501

My blog is Alameda Point Environmental Report covering environmental issues from wildlife to cleanup at the former Navy base in Alameda now called Alameda Point. Articles on my blog are frequently printed in the Alameda Sun newspaper. I also host a Twitter site and a Flickr photo site. I hope you find my stories and photos of interest. Richard Bangert Alameda, California

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