Re: Military Landfills

[WJASmith <wjasmith@aol.com>]

A note of caution regarding the EPAs presumptive remedy for
landfills, capping. In the Bay Area, where many landfills are
subject to tidal action moving water in and out the bottom of a
landfill twice a day, a cap will do little to prevent leaching
of contaminants.

A cap will also sometimes drastically alter the ecosystem by
changing drainage patterns, subsurface water flows, and
increasing the salinity of the water under the cap, especially
during the rainy season. For landfills whose current cover is
home to bird colonies and other wildlife, such as the West Beach
Landfill at the former Alameda Naval Air Station, either
excavation or leaving in place appears to be better than a cap.

In general a cap has two purposes, either to reduce leaching or
to make the material in the landfill less accessible to random
digging or exposure. If the first of these purposes is not
served, and access to the area will be controlled for the
indefinite future, the EPAs presumptive remedy of capping may be
expensive and unecessarily damage ecosystems. Instead, leaving
the landfill in-place and a long-term monitoring program
including sampling of the flora and fauna to detect ecological
damage, if any, caused by the landfill may be a more
constructive way to proceed.