This Section presents a summary of the key environmental
outcomes arising from the EIAFSS, including the population and
environmentally sensitive areas protected, environmentally friendly designs recommended,
key environmental problems avoided, and the environmental benefits of the
recommended environmental protection measures.
No unacceptable residual impacts are predicted for the
construction and operation of the facility at the East of Sha Chau site.
The EIA study has facilitated the integration of
environmental considerations into the design process for the Project. The principal measures identified are those
achieved through pit and dredging design, and backfilling and capping working
rates. In addition, a number of
mitigation measures have been identified to minimise the potential for adverse
environmental impacts. The
mitigation measures are detailed in full in the Implementation Schedule (Annex
E) and will be implemented by the Contractor under enforcement by the EPD.
One of the key environmental outcomes has been the ability
to plan, design and ultimately construct the project so that direct impacts to
sensitive receivers are avoided, as far as practically possible. A detailed assessment of alternative
sites within the Study Area has been conducted. Through this assessment, environmentally sensitive areas
have been protected by the following means.
·
Avoidance
of Direct Impacts to Ecologically Sensitive Habitats: The site for the East of Sha Chau Facility has been selected
based on a review of the environmental considerations of the area and the most
environmentally preferable site within the Study Area has been selected to
avoid direct impacts to ecologically sensitive habitats and species.
·
Avoidance of Indirect Impacts
to Ecologically Sensitive Habitats:
The site for the East of Sha Chau Facility has been selected so that it
is located at a sufficient distance from ecological sensitive receivers so that
dispersion of sediments from dredging, backfilling and capping operations does
not affect the receivers. By
locating the East of Sha Chau Facility in an area of low hydrodynamic energy
the horizontal dispersion of suspended sediment is restricted to a confined
area in close proximity to the pit boundary.
As a result, the assessments for this EIA have indicated
that it is not expected that the construction and operation of the East of Sha
Chau Facility will result in adverse impacts to environmentally sensitive
areas.
A key concern in the final site and disposal option design
was to take steps to ensure that both direct and indirect impacts through dredging,
backfilling and capping operations were avoided or minimised. Consequently, the following approaches
were adopted.
Adoption of Current Practices:
A review of all environmental monitoring data collected since the
commencement of operations at East of Sha Chau Contaminated Mud Disposal
Facility has demonstrated that mud disposal activities at the East of Sha Chau
area have remained within environmentally acceptable levels ([1]). As all dredging, backfilling and capping operations proposed
for the East of Sha Chau Facility have been designed to follow the current
practices, no adverse unacceptable impacts are expected to occur.
·
CMP Design: The East of Sha Chau CMPs have been designed as four
separate pits, which minimises the exposure time of contaminated mud to the
marine environment and consequently reduces the magnitude of any potential
impacts.
·
Adoption of Acceptable Working
Rates: The modelling work has demonstrated
that the selected working rates for the dredging, backfilling and capping operations
will not cause unacceptable impacts to the receiving water quality. Consequently, unacceptable indirect
impacts have been avoided.
Key environmental problems have been avoided through the detailed
site selection process that, as discussed above, allowed environmentally
sensitive areas and populations to be avoided. In addition, through the employment of practices that have
been demonstrated to be environmentally acceptable, no unacceptable
environmental problems are expected to occur as a result of the construction
and operation of the proposed East of Sha Chau Facility.
The construction and operation of the proposed East of Sha
Chau Facility will result in the temporary loss of low ecological value soft
bottom habitat. Following the
completion of capping operations, the seabed will be reinstated and is expected
to return to pre-dredging conditions.
As a result, compensation areas are not deemed necessary.
The design of the East of Sha Chau Facility will involve the
dredging of purpose-dredged pits, backfilling with contaminated mud and subsequent
capping with uncontaminated mud and/or natural uncontaminated soil to return
the seabed and hydrodynamic regime to their original condition. A review of long term monitoring data
from in and around the existing capped pits at East of Sha Chau has
demonstrated that within a relatively short period of time, recolonisation of
sediments occurs returning the site to a pre-dredged state. The employment of such environmental
protection methods in the design of the East of Sha Chau Facility will, therefore,
act as an environmental benefit.
This Environmental Impact and Final Site Selection Report
has critically assessed the overall acceptability of any environmental impacts
likely to arise as a result of the construction and operation of the proposed
contaminated mud disposal facility at East of Sha Chau. Where necessary and practicable, the
EIA has specified the conditions and requirements for the detailed design,
construction and operation of the Project in order to mitigate environmental
impacts to acceptable levels.
This EIA Study has predicted that the Project will comply
with all environmental standards and legislation following the implementation
of the recommended mitigation measures.
The EIA has thus demonstrated the acceptability of any residual impacts
from the Project and the protection of environmentally sensitive receivers and
populations. Where appropriate,
EM&A mechanisms have been recommended to verify the accuracy of the EIA
predictions and the effectiveness of the recommended mitigation measures.
In conclusion, it is considered that the EIA provides a suitable
basis for the Director of Environmental Protection to consider granting the
Environmental Permit to allow the construction and operation of the Project.