2.
Response
to
Comments
2.9
Individual
Responses
to
Comments
from
Organizations
Stormwater
treatment
measures
would
also
be
required
in
the
final
design
plans
in
accordance
with
the
San
Mateo
Countywide
Water
Pollution
Prevention
Program
C.3
Stormwater
Technical
Guidebook.
The
treatment
measures
would
vary
from
“local”
improvements
at
individual
building
sites
to
“areawide”
concepts
such
as
stormwater
treatment
wetlands
with
large
open
space
areas.
The
treatment
BMPs
would
be
required
to
include
one
or
more
of
the
following:
bioretention
areas
(including
bioretention
swales),
flow-through
planters,
tree
well
filters,
vegetated
buffer
strips,
infiltration
trenches,
extended
detention
basins,
pervious
paving,
green
roofs,
and
media
filter.”
As
stated
in
the
Draft
EIR
on
page
4.G-91,
no
construction
activities
within
affected
areas
would
commence
until
completion
of
formal
landfill
closure
and
remediation
of
and
is
achieved
(as
stated
in
Draft
EIR
Mitigation
Measure
4.G-2a:
“Prior
to
commencement
of
building
construction
or
site
grading
for
any
parcel
within
the
Project
Site,
the
project
applicant
shall
obtain
regulatory
approval
from
the
Department
of
Toxic
Substances
Control
(DTSC),
Regional
Water
Quality
Control
Board
(RWQCB),
and/or
the
San
Mateo
County
Environmental
Health
Division”).
Thus,
regulatory
approval
would
not
be
granted
for
activities
including
construction
of
pile
supports
in
a
manner
that
would
cause
or
allow
for
future
cross
contamination.
Construction
methods
to
isolate
vertical
groundwater
zones
are
commonly
employed
in
these
types
of
conditions
(see
for
discussion
of
the
potential
for
“cross-contamination”).
In
addition,
as
required
by
Mitigation
Measure
4.G-2b
on
page
4.G-93,
construction
activities
including
the
construction
of
pile
supports
would
occur
in
accordance
with
a
Soil
and
Groundwater
Management
Plan,
which
would
include
“site-
specific
safety
plans
[that]
shall
include
necessary
training,
operating
and
emergency
response
procedures,
and
reporting
requirements
to
regulate
all
activities
that
bring
workers
in
contact
with
potentially
contaminated
soil
or
groundwater,
landfill
gas,
or
leachate
to
ensure
worker
safety
and
avoid
impacts
to
the
environment.
The
Soil
and
Groundwater
Management
Plan
would
be
“reviewed
and
approved
by
DTSC
and
the
RWQCB
and
implemented
by
the
project
applicant.”
Therefore,
these
reporting
requirements
and
regulatory
approval
would
cover
all
construction
activities
including
any
core
sampling
and
pile
driving
activities
and
measures
would
be
required
to
ensure
that
all
construction
activities
do
not
result
in
adverse
effects
related
to
any
presence
of
legacy
contaminants.
The
discussion
under
Impact
4.H-3
of
the
Draft
EIR
beginning
on
page
4.H-26
is
directly
related
to
proposed
drainage
patterns,
and
provides
the
mitigation
(Mitigation
Measure
4.H-1c)
necessary
to
reduce
impacts
to
less
than
significant
levels.
The
analysis
of
Impact
4.H-4
directly
addresses
the
proposed
changes
related
to
the
potential
for
flooding
and
provides
detailed
mitigation
(Mitigation
Measures
4.H-4a,
4.H-4.b,
Brisbane
Baylands
Final
EIR
2.9.3-83
May
2015