2.
Response
to
Comments
2.9
Individual
Responses
to
Comments
from
Organizations
More
than
likely,
soil
was
also
placed
on
top
of
the
solid
waste
during
the
operations
of
the
landfill
as
“daily
cover”
to
prevent
the
materials
from
being
blown
into
the
community
or
the
Bay.
The
marine
sediments
are
comprised
of
Bay
Muds.
The
railyard
has
between
a
6
and
22
feet
deep
layer
of
undocumented
fill
on
top
of
Bay
Muds
that
are
compressible
and
range
from
0
to
50
feet
deep.
Underlying
Bay
Muds
are
layers
of
native
sand,
and
in
some
areas,
Old
Bay
Clay,
colluvium,
and/or
weathered
rock.
The
depth
of
the
Bay
Muds
gradually
increases
from
north
to
south
(Draft
EIR
Appendix
B).
The
geology,
therefore,
underneath
the
railyard
is
not
uniform.
The
variability
exists
in
both
the
fill
and
the
native
composition
of
the
earth.
This
is
not
unexpected
due
to
depositional
effects
of
the
San
Francisco
Bay
and
the
resulting
geologic
upheavals
from
earthquakes.
The
landfill
has
a
10
to
40
feet
deep
layer
of
fill
on
top
of
the
solid
waste.
Due
to
the
onsite
soil
recycling
operations
the
depth
and
condition
of
the
fill
cover
has
changed
over
time
based
on
demand
for
the
recycled
soil.
Beneath
this
layer
of
fill
is
a
20
to
35
feet
deep
layer
of
solid
waste
disposed
from
the
1930s
to
1967.
The
solid
waste
was
deposited
on
top
of
Bay
Muds.
The
first
layer
of
Bay
Muds
is
between
10
and
50
feet
deep
and
is
on
top
of
a
50
to
200
feet
deep
layer
of
Bay
Muds
intermixed
with
layers
of
sand
and
weathered
bedrock.
At
the
northern
edge
of
the
site,
a
30
to
100
foot
deep
sand
layer
has
been
identified
(Draft
EIR,
Appendix
B).
The
Overview
of
Project
Site
Hydrogeology
section
referenced
in
this
comment
is
a
summary
of
regional
groundwater
conditions.
Contaminants
in
groundwater
are
not
discussed
in
this
section
since
it
addresses
groundwater
gradient
and
the
potential
for
groundwater
underlying
the
site
to
be
influenced
by
tidal
action
and
contribute
to
the
generation
of
leachate
from
the
landfill.
See
for
discussion
of
the
adequacy
of
existing
studies
for
use
in
the
Draft
EIR.
See
for
discussion
of
tidal
action.
See
for
discussion
of
tidal
action.
See
for
discussion
of
the
remediation
review
and
approval
process.
As
discussed
in
that
Master
Response,
Title
27
closure
under
the
regulatory
authority
of
the
RWQCB
will
be
required
to
prevent
any
increases
in
leachate
that
exceed
any
regulatory
thresholds.
See
for
discussion
of
tidal
action
in
relation
to
the
former
landfill.
Title
27
closure
of
the
former
Brisbane
Landfill
will
be
required
to
prevent
any
increases
in
leachate
that
exceed
any
regulatory
thresholds.
Brisbane
Baylands
Final
EIR
2.9.1-38
May
2015