REVIEW OF THE DRAFT WORK PLAN FOR PRE-DESIGN INVESTIGATION OF SEDIMENT
AT INSTALLATION RESTORATION SITE 25,
MOFFETT FIELD, SANTA CLARA COUNTY, CALIFORNIA
Comment
Number
Section/
Page
Comment
Response
Comments from the United States Environmental Protection Agency, Sarah Kloss, dated May 14, 2010
1.
Section 2.3,
Page 2-3:
Please change the word “sediment” to “soil” in the last
sentence of this section.
The last sentence of Section 2.3 will be revised as follows:
“…pesticides; and various soil areas contaminated with PCBs (referred to as
upland source areas addressed separately by NASA, Navy, and U.S. Army, not
as part of the remedial design of IR Site 25).”
2.
Section 3.2,
Page 3-1:
Please change the phrase “under the auspices of” to
“pursuant to.”
The text has been revised as follows:
“This Work Plan for pre-design investigation sampling of sediment at Moffett
Field is being conducted pursuant to a Federal Facilities Agreement that
provides a procedural framework and schedule for the CERCLA cleanup
process at Moffett Field.”
3.
Section 4.4,
Page 4-3:
Please add criteria that will be used to determine if a
bathymetric survey is needed.
A topographic survey and/or a bathymetric survey will be required to support the
development of the Remedial Design. A topographic survey is preferred
because it is more precise and cost-effective. The bathymetric survey may,
however, be required depending upon the extent of standing water in the ponds
at the time of the survey. For this reason, the text specified that either or both
surveys will be required.
For clarification, Section 4.4 of the Work Plan and SAP Worksheet #17,
Section 17.3 will be revised to the following:
“A topographic and/or bathymetric survey will be conducted as part of the predesign investigation. The need for a bathymetric survey will be determined
based on the amount of standing water in the ponds at the time of the survey.”
Additionally, the following sentence will be added to SAP Worksheet #14, page
14-1 for clarification:
“The need for a bathymetric survey will be determined based on the amount of
standing water in the ponds at the time of the survey.”
4.
Worksheet (WS)
#17, Section
17.1.1,
Page 17-1:
Paragraph 2 refers to Figure 10-8 to show the defined
upper and lowers areas; however, this figure does not
include a boundary between “upper” and “lower.”
Please edit Figure 10-8 to visually define the upper
and lower areas referred to in WS #17.
The terms “upper” and “lower” areas were used to distinguish between those
samples collected for hot spot detection (star symbols) and those to refine the
remedial design (triangle symbols), as defined in the legend of the figure.
Figure 10-8 will be revised to show the division between the upper and lower
areas of the site.
KCH-2622-0007-0016
Page 1 of 2
August 2010
REVIEW OF THE DRAFT WORK PLAN FOR PRE-DESIGN INVESTIGATION OF SEDIMENT
AT INSTALLATION RESTORATION SITE 25,
MOFFETT FIELD, SANTA CLARA COUNTY, CALIFORNIA
Comment
Number
Section/
Page
Comment
Response
5.
WS #17, Section
17.1.1, Page
17-2:
The second paragraph of this page states that
“Seventeen of the surface samples will be collected
from 17 of the 28 sample locations in the upper
area…” The word choice implies that there are 28
samples in the upper area alone, not 28 samples total.
The same language exists for the lower area. Please
edit the text to be clear that there are 28 samples
total, 17 in the upper area and 11 in the lower area.
The text will be revised as follows:
“Seventeen of the 28 surface sediment samples will be collected from locations
in the upper area of IR Site 25 (within the northern portion of the three
subareas) to verify that hot spots of contamination do not exist in areas that are
not currently targeted for remediation.”
And…
“Eleven of the 28 surface sediment samples will be collected from locations in
the southern portion of the Central Basin to refine the size and shape of the
polygon areas targeted for remediation.”
6.
WS #17, Section
17.2, Page 17-3:
Please clarify the approval process once the wetland
and sensitive habitat evaluations are complete. For
example, will the US Army Corps of Engineers make a
determination based on the Navy’s wetlands
evaluation?
The wetland and sensitive habitat evaluations are being conducted to establish
baseline conditions at the site prior to the Remedial Design. These evaluations
will not undergo a formal approval process. As discussed in the ROD, no formal
permits are required under Section 121(e) of CERCLA (42 USC, Section
9621[e]); but the Navy will comply with the substantive provisions of the permit
as a means to ensure compliance with the substantive portions of the ARARs
for excavating and backfilling in the wetland areas of the Eastern Diked Marsh.
As part of the remedy, the Navy will restore and revegetate the wetlands where
necessary and will monitor the recovery of the wetlands.
7.
WS#17, Section
17.4, Page 17-4:
Please specify the approximate volume of soil that will
be used for each treatability study sample. Also,
please add additional text to justify that the 48 hour
timeline for the final sample is sufficient to determine
the long term efficacy of the stabilizing agents.
While 24 hours should be enough for the curing time, we have added 1 more
day to the treatability study to confirm the curing time. Therefore, the 48-hour
timeline for the final sample is sufficient to determine the long-term efficacy of
the stabilizing agents.
Section 17.6.3.2, Item 1, states that 5 gallons of sediments and debris will be
collected.
The following text has been added to WS#17, Section 17.4, Page 17-6:
“A curing time of 24 hours should be sufficient; however, 48 hours will be
allowed to confirm that curing is complete.”
KCH-2622-0007-0016
Page 2 of 2
August 2010