3.
EIAO REQUIRMENTS AND APPROACH TO ASSESSMENT
3.1
Requirements under Environmental Impact
Assessment Ordinance
3.1.1
The
proposed construction and operation of the Hong Kong West Drainage Tunnel,
including drop shafts to collect storm runoff from the uplands of Hong Kong
Island to a discharge point located adjacent to the Cyberport Phase I at the
former Sandy Bay. The proposal works is considered to be a Designated Project
(DP) under the Environmental Impact Ordinance (EIAO) Schedule 2, Part I, Q1, the
proposed tunnel underground alignment falls within the Aberdeen Country Park,
3.2
Purpose of the EIA Study
3.2.1
The
purpose of this EIA is to provide information on the nature and extent of
environmental impacts arising from the construction and operation of the
proposed DP and any related activities taking place concurrently. This EIA is
aimed at providing the following:
i)
An
evaluation of the overall acceptability of any adverse environmental
consequences likely to arise due to the DP;
ii)
Recommendations
on conditions and requirements to be imposed on the detailed design,
construction and operation of the DP;
iii)
An
evaluation of the acceptability of the residual impacts after the recommended
conditions and requirement on the detailed design, construction and operation
of the DP.
3.3
Approach of the EIA Study
Interaction
with ongoing design
3.3.1
Environmental
considerations had been part of the planning process undertaken for this
Assignment from the outset. The choice of an environmentally appropriate
alignment, as illustrated in Section 2, has been the goal from the conception. This
EIA Study and the relevant assessments are to demonstate the environmental
acceptability for the preferred alignment Option C(3). Its findings contribute
to the decision making process of the ongoing preliminary design. This way,
potential environmental impacts can be prevented or reduced at an early design
stage.
3.3.2
Changes
of the preliminary design are assessed in terms of their environmental
implications. The findings are in turn fed into the ongoing preliminary design.
As a result the environmental impacts are minimized by an iterative process as
the preliminary design progresses. Hence this EIA adopts an approach of
assessing and preventing impacts as it is conducted.
3.3.3
The
following is an example of responding to design changes in the EIA. Since the
completion of the EIA inception report, the proposed reclamation for
landscaping area at the Western Portal was cancelled. Therefore, the chance of construction
phase water quality impact and ecological impact occurring has been reduced. These changes are reflected in the water
quality and ecological impact assessment.
3.3.4
An
example of the EIA influencing the design process and implementation planning
is provided here. The key issue that influences the design decision most is the
potential construction noise impact. Since construction works for the intake
shafts will have to be carried out at close distance from noise sensitive
receivers, airborne construction noise impact is significant. The construction
method have been reviewed and revised to ensure the duration of noisy
activities, number of noisy equipment are minimized.
Approach for Designing Mitigation Measures
3.3.5
When a
potential impact is predicted to occur, in both qualitative sense and when the
impact is expected to breach statutory or non-statutory guidelines, the
approach of impact management is to advocate the avoidance, prevention and
minimization of the potential environmental impacts before considering
purpose-built mitigation measures.
(1)
As a
result the following priority is given when considering the approach for
reducing the potential and residual environmental impacts to an acceptable
level:
(2)
Liaison
with the design team to consider alternative designs and construction methods
to avoid creating an environmental impact.
(3)
Re-scheduling
and re-organization of the impact causing activities to avoid or prevent the
environmental impact.
3.3.6
Proposals
for purpose-built technical or administrative mitigation measures, either on
their own or to supplement the alternative design / construction method,
re-scheduling and re-organization of activities.