CIWMB’s Solid Waste Information System (SWIS) number: 12-AA-0005
Site Information per
Landfill Facility Compliance Study (Task 2)Information Source:
Owner/Operator—Humboldt Waste Management Authority
Telephone conversation: April 14, 2004
E-mail response: May 7, 2004
The Humboldt Waste Management Authority took over ownership of the landfill
from City Garbage Company about 3½ ago. The Cummings Road Landfill began
operations in the 1930s as a burn dump. There has been groundwater
contamination observed down-gradient of the site, which originated from this
unlined area. Over the years, corrective actions have been implemented to
address the groundwater problem. In the mid-1990s, the previous owner
excavated the up-gradient groundwater diversion trench in an effort to
divert the water flowing in the Hookton Formation from the waste mass. Soil
from this excavation was then used to construct a buttress at the toe of the
landfill. In addition, the previous owner provided a municipal water supply
to down-gradient residents affected by the groundwater contamination.
The previous owner’s actions, and the passage of time, have improved the
condition of down-gradient groundwater. There are still occasional
exceedances of drinking water standards† (which is the water standard for
this site) in the groundwater monitoring wells, but given the site’s
history, these exceedances are not surprising.
The site has a very wet climate. Up to 10,000 gallons of leachate are
collected per day. As such, the owner’s corrective action experiences may
not be directly comparable to other sites in the state with dissimilar
conditions.
Currently, the Cummings Road Landfill is inactive, and Humboldt County’s
waste stream is being shipped out of the county. The owner is trying to
cover and close the landfill. Applying final cover to the landfill is
expected to reduce water infiltration and help reduce impacts to the
groundwater. To construct a final cover over the landfill and promote
runoff, the upper part of the landfill will need to be regraded. The owner
wants to accept clean fill at the landfill in order to achieve an
appropriate final grade. The owner submitted a clean soil acceptance plan to
the regional water quality control board (RWQCB) and is awaiting approval.
It is the owner’s opinion that the lengthy approval process is hindering the
owner’s ability to install systems that may improve the environmental
performance of the site. In January 2003, the owner submitted a closure plan
for the final closure of the site. The regulatory review process is ongoing,
and the closure plan has not yet been approved. Closure construction has not
begun.
Without approval of the clean soil acceptance plan, the grades of the
landfill have not changed appreciably in recent years. During the rainy
months, ponding occurs over portions of the site. While the owner is
required to submit yearly topographic surveys, these surveys have not been
performed, as the topography has not appreciably changed.
The owner is conducting surface water and stormwater monitoring. Unlike the
groundwater monitoring program, the surface water and stormwater monitoring
program does not include reportable limits. Because there is no uniform
standard that is being upheld, the owner has found compliance with the
monitoring requirements to be somewhat confusing.
A few years ago, there were landfill gas (LFG) migration compliance issues
at the site. With the installation of additional gas extraction wells, the
owner was able to bring the site back into compliance.
Information Source: North Coast Regional Water Quality Control Board
Telephone conversation: April 9, 2004
E-mail response: May 6, 2004
This site has been in a corrective action program (CAP) since 1990. Between
1993 and 1998, the owner implemented the following corrective action
measures: (1) installation of an interception trench in the Hookton
Formation; (2) installation of a toe berm; and (3) installation of leachate
and gas collection systems. Waste Discharge Requirements (WDR) 93-43
indicate that final cover is a fourth element of the corrective action plan,
but has not been installed to date. In addition to these corrective action
measures, neighbors who were obtaining their domestic water supplies from
on-site wells were given the opportunity to be connected to the Eureka
municipal water supply because of the large contamination plume extending
approximately ¾ mile from the waste footprint. A bottled water plant also
moved because its water supply had become contaminated by the plume. Until
the last few years, the corrective action measures implemented seemed to
have stopped plume migration, but have not appreciably reduced contamination
concentrations. Any constituents above background levels (or non detect [ND]
for man-made compounds) in the surface or groundwater are considered a
release, and corrective action will require full cleanup of any release or a
demonstration that full cleanup is infeasible, per Title 27 of the
California Code of Regulations.
In April 2001, the owner reported volatile organic compound (VOC) detections
in the groundwater monitoring well located at the base of the canyon and
down-gradient of toe buttress. These detections differ from earlier
pollutant detections at the site, in that they occurred in the lower Wildcat
formation, rather than in the upper Hookton Formation. The owner submitted
an engineering feasibility study which recommended installing additional
monitoring wells and performing final closure of the landfill as a
corrective action. There is currently additional evaluation monitoring
taking place to investigate a new detection of methylene chloride (first
detected September 2003) to Woodgulch Spring and MW-40-H.
The owner submitted a second version of the final closure plan in February
2003. Regional Water Board staff deemed the document to be incomplete, and
the regulatory agencies are continuing discussions with the owner’s
consultants regarding the issues involved. The owner has not yet submitted a
complete joint technical document (JTD) for the site; the final closure plan
is one component of a complete JTD.
Settlement and stability of the toe berm may impede closure of the site. The
owner is conducting visual monitoring for settlement cracks on the toe berm,
on days when site personnel are present. Site personnel have been attempting
to divert surface water from this area. During the dry season, site
personnel have been plugging significant cracks with powdered bentonite
clay. The RWQCB has requested that the owner track the vertical displacement
of the toe berm in order to determine whether settlement issues are related
to stability. Data from this tracking effort can also be used to determine
when the toe berm has stabilized.
The regulations have been effective in encouraging the owner to take action
to address the site’s groundwater problems. However, full cleanup will take
a significant amount of time. The groundwater-related regulations have not
been overly difficult, costly, or confusing to implement at this site. If
there is a lesson to be learned from this site, it is that operators should
maximize leachate and gas removal from the waste footprint, starting as
early as possible in the life of the landfill, because once pollutants reach
the groundwater, they are far more difficult to effectively control.
Information Source: Enforcement Agency—Humboldt County Health Department,
Environmental Health Division
Telephone conversation: April 1, 2004
E-mail response: April 28, 2004
According to the EA, the LFG control issues identified in the CIWMB’s
Landfill Facility Compliance Study database evolved over time. The original
violations occurred prior to the study period because the owner was not
conducting the monitoring required by the regulations. The operator had no
wells and the solid waste facility permit revision was withdrawn. The site
was listed on the CIWMB’s inventory of sites violating minimum standards. In
response to the listing, two monitoring wells were installed, and then three
additional monitoring wells were installed.
During the monitoring of the probes, methane in excess of 5 percent was
detected and additional notices of violation (NOV) were issued. In response
to these detections, the LFG extraction system was expanded and the methane
concentrations decreased. After the addition of two more extraction wells,
the site came into compliance and was removed from the CIWMB inventory. The
actions taken to bring the site into compliance were somewhat of a
trial-and-error process. After the system was installed and adjusted, more
extraction wells were added, and eventually, compliance was achieved
With respect to the off-site LFG migration regulations and their ability to
protect human health, there is no differentiation between impact to
populated areas versus non-populated areas. In the case of Cummings Road
Landfill, the areas adjacent to the methane exceedance are non-populated
timberlands. There is no distinction in the regulations between this
situation and a situation where there are people living at the property
boundary.
Experience at this site also demonstrates a difference in the regulatory
approaches between resolving LFG exceedances and groundwater exceedances.
With respect to groundwater, the regulations provide a defined series of
steps from detection monitoring through corrective action with time allowed
to investigate the problem and design a solution. With respect to LFG, the
regulations simply require compliance and do not define the process or
specify the time in which to achieve compliance.
This EA also issues well permits. According to the EA, while the permit
applications received for groundwater wells tend to be fairly consistent
from application to application, there is little consistency in construction
of gas wells throughout the industry. At Cummings Road Landfill, this
variability in construction has slowed the approval process for these wells.
The EA suggests that either a broad-based industry standard or statewide
guidance document for gas well construction would help to streamline the
approval process.
Since the beginning of the study period (January 1, 1998), the EA has not
issued any surface water-related enforcement actions and there have been no
surface water regulations that have been overly difficult, costly, or
confusing at this site. The EA did mention that, while not part of the
regulations themselves, the WDRs require winterization by certain deadlines
each year to reduce potential impacts from the landfill to surface water; at
Cummings Road and other sites with similar wet climates, these efforts are
essential.
Information Source: North Coast Unified Air Quality Management District
Telephone conversation: March 31, 2004
E-mail response: May 27, 2004
The facility, known as the Humboldt Municipal Landfill, has been operating
under an air quality permit since August 1997. The air quality management
district (AQMD) has not issued a notice to comply (NTC) or notice of
violation (NOV) for air quality issues at the site since the beginning of
the study period (January 1, 1998). There have been no additional air
quality protection measures taken at Cummings Road that are beyond the
regulatory minimums.
An annual compliance inspection, conducted in April 2004, revealed a series
of procedural violations including the failure to obtain authority to
construct permits, missing reports of breakdown events, and miscellaneous
record-keeping requirements. No emission violations were observed.
†All
drinking water requirements set forth in the California Safe Drinking Water
Act (section 116275 et. seq. Health and Safety Code) and the regulations
adopted by the Department of Health Services pursuant thereto.
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