2.
Response
to
Comments
2.9
Individual
Responses
to
Comments
from
Organizations
Soil
liquefaction
describes
a
phenomenon
whereby
a
saturated
or
partially
saturated
soil
substantially
loses
strength
and
stiffness
in
response
to
an
applied
stress,
usually
earthquake
shaking,
causing
it
to
behave
like
a
liquid.
Subsidence
refers
to
the
sinking
of
the
ground
surface.
These
definitions
do
not
change
with
native
or
different
types
of
fill
soil.
See
for
discussion
regarding
the
adequacy
of
existing
studies
for
use
in
the
Draft
EIR.
Because
these
existing
studies
provide
adequate
characterization
of
the
contents
of
the
landfill
for
use
in
the
Draft
EIR,
an
additional
search
of
Sunset
Scavenger
Waste
records
is
not
necessary.
See
also
13
for
discussion
of
the
remediation
review
and
approval
process.
Leachate
and
landfill
gas
collection
and
control
systems
will
be
required
to
adequately
collect
leachate
and
landfill
gas
from
the
former
landfill
to
prevent
any
increases
in
leachate
that
exceed
any
regulatory
thresholds
and
thereby
reduce
impacts
to
the
Brisbane
Lagoon
and
creeks.
Because
the
former
Brisbane
landfill
operated
prior
to
current
permitting
requirements,
the
contents
of
the
landfill
were
not
formally
documented
as
they
were
deposited
into
the
landfill.
Borings
and
testing
of
landfill
contents
have
therefore
been
necessary
to
identify
the
contents
of
the
former
landfill
and
provide
information
on
potential
health
risks.
See
for
discussion
of
the
remediation
review
and
approval
process.
See
for
discussion
of
the
Title
27
landfill
closure
review
and
approval
process.
The
term
“clean
soil”
is
a
common
term
used
in
the
construction
industry
to
denote
soils
that
are
free
of
rubble
and
construction
debris.
As
used
in
the
Draft
EIR,
it
refers
to
the
20
to
30
feet
deep
layer
of
soil
used
as
cover
over
the
landfill
to
prevent
human
contact
with
refuse
from
residential,
commercial,
industrial
activities
including
shipyard
waste,
construction
rubble,
tires,
and
sewage.
It
is
not
likely
that
soils
used
for
the
interim
landfill
cover
were
tested
prior
to
their
being
placed
on
the
former
landfill.
However,
Title
27
landfill
closure
will
be
designed
so
as
to
avoid
creation
of
new
exposure
pathways,
including
pathways
from
the
interim
cover
placed
on
the
former
landfill
during
final
closure
as
required
by
Title
27.
Because
the
final
landfill
cover
will
require
excavation
and
stockpiling
of
the
interim
cover,
testing
(and
if
required
remediation)
of
the
existing
soil
cover
will
be
included
as
part
of
formal
landfill
closure.
Based
on
records
of
the
waste
placed
in
the
former
Brisbane
Landfill,
the
waste
stream
has
been
classified
as
Brisbane
Baylands
Final
EIR
2.9.3-51
May
2015