REMEDIAL ACTION WORK PLAN OPERABLE UNIT 2, LANDFILL ...

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are meant to define those areas which deviate from the approved design. BCT approval is
requested to adapt these improvements to the approved design.
None of these improvements are changes to the basic design concepts and performance
specifications approved in the HLA design documents. Therefore, no Explanation of Significant
Differences (ESD) amendments are required to the ROD based on these contractibility
improvements. The only ESD required to the ROD is currently under review by the EPA, state
and Regional Water Quality Control Board (RWQCB) which adds cleanup criteria to the areas to
be consolidated.
Language will be added to clearly reference the HLA design documents except as they are
needed by the improvements as shown in the RAWP and specifically detailed in Table 6.1,
Constructibility Improvements. Table 6.1 verbiage will be enhanced to say that these
improvements are incorporated in the RAWP.
Again, no design changes impact the record of decision. In our opinion, there are no “sweeping
design changes” being proposed. The design, in our opinion, is frozen as capped landfill areas
within a low permeable liner and vegetative cover.
Changes such as the perimeter berm configuration are not considered a major change but
refinements to the existing design.
The deletion of the drainage system piping is considered an improvement in that it avoids the
concentration of storm water and allows the deletion of the storm water basins. Further, the
deletion of the storm water drainage piping system in the vegetative cover layer eliminates a
major erosion potential in the collectio~ swales. In addition, it allows for better access during the
post closure operation and maintenance (O&M) years.
Slopes and slope stability are both regulated (min.hnax) and engineered and these improvements
are within the regulatory parameters of minimums and maximums.
It is not our intent to pursue changes outside the regulatory limits. IT does, however, consider it
prudent of us all to pursue the most cost effective engineering practices and construction methods
available within regulatory constraints.
Action:
Section 1;0, add this explanation after the third paragraph.
1. Comment:
The list of Acronyms and Abbreviations is not shown in the Table of Contents, and the list is
incomplete (see appendix F).
SJ/4-23-96/SACTERC/FTOKDOU2/USEPA
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