CIWMB’s Solid Waste Information System (SWIS) number: 41-AA-0010
Site Information per
Landfill Facility Compliance Study (Task 2)
Ceased accepting waste before 1993Information Source: Owner/Operator—City of San Mateo
Telephone conversation: March 18, 2004
E-mail responses: March 19, 2004 and April 6, 2004
The interviewee does not believe that the site has been required to
undergo corrective action and/or been issued a cleanup and abatement
order (CAO) since the beginning of the study period (January 1, 1998).
No additional groundwater protection measures beyond the regulatory
minimum requirements have been implemented at the site. The interviewee
stated that there are no specific groundwater related regulations that,
if followed, are overly difficult or costly without protecting the
environment or that have been too confusing or contradictory to
implement at the site. The interviewee did not know of any gas-related areas of concern (AOC)
or violations at the site since the beginning of the study period
(January 1, 1998). However, the perimeter monitoring system was
increased from three wells to six as part of the landfill's closure
plan. No other gas-related protection measures have been implemented. As
the site produces very little gas, the owner needs only to run a
monitoring program in order to comply with gas regulations. The waste in
the landfill is composed of clean fill soils, garden wastes,
construction and demolition debris, street sweepings, creek and channel
cleanings, and city maintenance debris (non-garbage) and incinerator ash
from the wastewater treatment plant. The site has been issued an AOC, violation report, or enforcement action
for not meeting minimum surface water-related standards, but the
interviewee was not able to locate an AOC or other action regarding
surface water in the files. However, the interviewee indicated that
sites like East Third Avenue, which are located close to a large water
body, and tributaries like San Francisco Bay, are difficult to monitor. The site has not had any air quality issues or concerns since the
beginning of the study period (January 1, 1998). A geosynthetic clay liner (GCL) has been used for the final cover. The
interviewee stated that the main reasons for selecting a GCL was
minimizing thickness. The ¼-inch thick GCL layer could be used in place
of a 1-foot thick layer of clay material, which allowed capping of the
raised portion of the landfill without increasing the side slopes The
thinner cap design will also benefit a second and ongoing phase of the
project that caps a relatively flat portion of the landfill underneath
voltage transmission lines. The high-voltage conductors hang low
relative to their minimum clearances allowed by California Public
Utilities Commission General Order 95. Use of GCL will allow the site to
minimize the thickness of the additive cover and therefore remain
compliant.
Information Source: San Francisco Regional Water Quality Control Board
E-mail responses: March 8, 2004 and March 9, 2004
Since the beginning of the study period (January 1, 1998), the site has
been in a detection monitoring program and has not been placed in a
corrective action program (CAP) or come under a water-related CAO. There
are no specific groundwater-related regulations that, if followed, are
overly difficult or costly without protecting the environment, nor are
there any groundwater-related regulations that have been too confusing
or contradictory to be implemented or enforced at the site. A GCL is being used to construct the final cover. Since GCL is not a
regulatory requirement, (a compacted clay liner is), the regional water
quality control board (RWQCB) was unsure why GCL had been selected. The
RWQCB stated that GCL would not be necessarily recommended over a
compacted clay liner, since each selection has advantages and
disadvantages.
Information Source: Enforcement Agency—County of San Mateo, Department
of Health
E-mail responses: March 26, 2004 and April 27, 2004
The GCL final cover system is performing well. However, problems
occurred during installation of the GCL with respect to oversized
particles in the vegetative layer. The concern was that the closure
construction quality assurance (CQA) and closure plan for the Phase One
aspect of the work was not following the plan. Large pieces of rock and
concrete and some solid waste materials were observed in the vegetative
cover. The section in the closure CQA plan stated that no rock greater
than ¾ of an inch is accepted in the vegetative layer. It appeared that
this specification was not being looked at or that the specification was
written too restrictively. Later, the plan was modified to a more
reasonable standard. No AOC or violations been received for gas-related issues at the site
since the beginning of the study period (January 1, 1998). No additional
gas-related protection measures have been implemented beyond the
regulatory minimums. The lack of a good functioning drainage system has caused ponding, and
the site has been issued a surface water-related AOC. The AOC has not
become a violation and no enforcement action has been taken. The site is
currently going through closure construction, so some of this activity
will correct the problems. Before the construction activities commenced,
actions by the owner to correct the situation at the site were limited.
The agency believes that the existing landfill regulations allow
landfill surface water issues to be mitigated appropriately.
Information Source: Bay Area Air Quality Management District
Telephone conversation: March 16, 2004
There is no information available in the Bay Area Air Quality Management
District files for the East Third Avenue landfill.
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