Soil cover being installed at future park site

The Navy made significant headway in June and July on its third and final environmental remediation soil-cover project on the Alameda Point airfield, with 7,289 truckloads of soil being hauled in from an East Bay Municipal Utility District soil-storage site in Castro Valley.  The frenzy of truck traffic through the Tube and down Main Street led to complaints of speeding trucks and running red lights, prompting the Navy to warn truck drivers that they could be removed from the job for violating traffic laws, and the City of Alameda Police Department to step up traffic enforcement.

A temporary mountain of approximately 200,000 cubic yards of stockpiled soil is visible on the western end of the airfield during a ferry ride to San Francisco from the Main Street Ferry Terminal.  Another 100,000 cubic yards of cover soil and 60,000 cubic yards of top soil for new vegetation is expected to be delivered by November.  The soil will be used to create a three-foot cover over the 60-acre cleanup site by the end of 2020.

The land will be turned over to the city for use as recreational open space when the $24 million environmental cleanup project is completed.  Talks are underway between the city and the East Bay Regional Park District for the park district to construct and operate a 150-acre regional park along the shoreline that will include this cleanup site.

Some people question the Navy’s choice of installing a soil cover to remediate for contamination since, technically speaking, the contaminants aren’t being cleaned up but covered up.  An alternative method of cleanup that was considered but rejected would have dug out all the soil to a depth of 10 feet over the entire 60 acres and replaced it with clean soil at an estimated cost of $79 million, with a different set of environmental impacts.

In the case of the current 60-acre cleanup site, dubbed Site 32, the Navy and regulators considered a less expensive cleanup alternative that would have removed a dozen or so spots with contamination, mainly radium-226 luminescent paint waste.  The reason for rejecting that alternative is that, despite over 280,000 scanning data points being logged, radiation scanning is only accurate to a depth of one foot.

Thus, the spot cleanup method would have left a lingering question mark as to what might lie a few inches deeper.  Even though radium-226 only poses a radiation health hazard when ingested, and hiking and biking uses would not be expected to unearth bits of contamination, one foot of soil was not deemed a sufficient barrier.  Out of an abundance of caution, the site will get a minimum of three feet of clean soil seeded with native vegetation, including a completely re-engineered and enhanced wetland.

Meanwhile, during the same time period beginning this fall, the Navy will also be embarking on a $5 million shoreline stabilization project along the edge of this soil cover and another adjacent soil cover on Site 1 that wraps around the tip of Alameda Point to the Bay.  It is a complementary project that was recently added.  It differs from other cleanup projects in that its goal is not to remove or cover up contamination.  Instead, it is a form engineering insurance to make sure the adjacent cleanup work remains intact.

Without reinforcement of the shoreline, the integrity of the soil covers could be at risk from storm surges, wave action, erosion, and earthquakes.  The rock and masonry shoreline that is holding the soil covers in place is old, with the section along the Estuary first constructed in the late 1800s by the U.S. Army Corps of Engineers.

The large pile of soil in the photos is not part of the shoreline stabilization project.  The soil in the photos will be bulldozed around the 60-acre site and down to the shoreline of the Estuary where new rock reinforcements will be put in place during the stabilization project.  The shoreline stabilization project and its historical background will covered in an upcoming story.

A version of this story originally appeared in the Alameda Sun.