2.
Response
to
Comments
2.10
Individual
Responses
to
Comments
from
Individuals
A
third
party
acoustical
consultant
was
retained
to
consider
the
acoustical
effects
of
Brisbane’s
topography
and
the
effects
it
may
have
on
the
analysis
of
noise
impacts
of
the
Draft
EIR.
The
consultant’s
findings
determined
that
the
shape
of
the
terrain
in
Brisbane
and
the
slope
of
the
valley
means
that
homes,
like
seats
in
an
amphitheater,
have
a
“good
view”
of
noise
sources.
This
means
that
noise
will
propagate
better
than
in
a
typical
flat
community
because
buildings
are
less
likely
to
intercept
the
line-of-
sight
to
a
noise
source.
Because
the
noise
predictions
in
the
Draft
EIR
do
not
assume
any
acoustical
shielding
by
intervening
buildings,
they
are
therefore
appropriate
for
the
analysis,
given
Brisbane’s
terrain.
Similar
noise
predictions
would
tend
to
be
more
conservative
for
more
low-lying
areas
of
the
community.
Table
4.J-1
of
the
Draft
EIR
presents
noise
monitoring
data
collected
to
establish
the
existing
noise
environment
within
the
City
of
Brisbane.
Ambient
noise
was
monitored
at
eight
locations
all
of
which
are
within
the
City
of
Brisbane,
six
of
which
were
on
the
flatlands
and
two
of
which
were
at
elevations
of
75
and
225
feet
above
mean
sea
level,
respectively.
Project
Site
development
would
not
result
in
a
meaningful
increase
in
aircraft
operations
at
San
Francisco
Airport
and
would
not
result
in
an
increase
in
aircraft-related
noise
exposure.
With
regard
to
vibration,
some
construction
equipment,
such
as
pile
driving,
would
generate
noise
levels
in
the
flatlands,
the
impacts
of
which
are
assessed
in
Impact
4.J-2
of
the
Draft
EIR.
As
physical
phenomena,
sound
waves
through
air
and
vibration
through
the
ground
are
separate
considerations.
While
low
frequency
noise
can
cause
windows
and
walls
to
vibrate,
this
type
of
noise
would
not
be
expected
from
construction
activities
or
increased
traffic
volumes
associated
with
Project
Site
development
because
of
the
frequency
of
the
noise
waves
generated
by
these
sources.
As
stated
on
Draft
EIR
page
4.E-11,
San
Bruno
Mountain
consists
of
uplifted
sandstone
and
shale
rocks,
which
are
sedimentary,
not
crystalline.
Thus,
there
is
no
evidence
to
support
an
assertion
that
San
Bruno
Mountain
would
increase
vibration
or
noise
impacts
of
proposed
Baylands
development.
The
perception
of
sounds
being
louder
or
amplified
is
best
explained
by
the
effect
of
Brisbane’s
terrain,
which
tends
to
act
as
a
noise
barrier
for
ground
based
noise
sources,
block
noise
generated
outside
of
the
community,
making
other
sounds
more
noticeable.
In
addition,
the
slope
of
the
valley
means
that
homes,
like
seats
in
an
amphitheater,
have
a
“good
view”
of
noise
sources.
Thus,
noise
generated
within
by
the
US
101
freeway
and
within
the
Baylands
will
propagate
better
than
in
a
typical
flat
community
because
buildings
are
less
likely
to
block
the
line-of-sight
to
a
noise
source.
Since
the
noise
predictions
in
the
Draft
EIR
do
not
take
assume
Brisbane
Baylands
Final
EIR
2.10.19-13
May
2015