13 Summary of
Environmental Outcomes
13.2 Environmental Friendly Options
Considered and Incorporated to Avoid Environmental Impact
13.3 Environmental Designs Recommended to
Minimise and Mitigate Environmental Impacts
13.4 Summary of Key Environmental
Problems Avoided and Sensitive Areas Protected
13.5 Estimated Population Protected from
Various Environmental Impacts
13.6 Environmental Benefits of
Environmental Protection Measures Recommended
13.1.1.1
This
section summarises the overall environmental outcomes due to the construction
and operation of Lai Chi Wo (LCW) Pier in accordance with Section 3.6.1 of
the Environmental Impact Assessment (EIA) Study Brief No.: ESB-305/2017. It can
be seen in Section 1 and Section 2 that environmental
considerations have been the key considerations throughout the development of
the Project. Alternative options for designs and construction methodologies
have been duly considered. Besides, all
the options considered have ensured that environmental impacts could be avoided
or minimised where practicable and mitigated by implementation of suitable
mitigation measures to fulfil all the statutory requirements. The technical
assessments conducted (Section 3
to Section 11) have
demonstrated that all the statutory requirements in the EIA Study Brief (ESB-305/2017)
and Technical Memorandum of the Environmental Impact Assessment Ordinance
(TM-EIAO) have been compiled with.
13.1.1.2
The
following sections summarise the approaches that have been adopted to either
avoid or minimise various environmental impacts throughout the design process,
and the associated environmental enhancements.
13.2 Environmentally Friendly Options Considered and Incorporated to Avoid Environmental Impact
13.2.1.1
Avoidance
of environmental impacts has been one of the key considerations throughout the
entire project development and design. The environmental impacts that have been
avoided are listed and discussed below:
·
Avoidance
of open sea dredging works;
·
Avoidance
of wastewater / effluent discharge during both construction and operational
phases; and
·
Avoidance
of solid pier design.
13.2.2 Avoidance of Open Sea Dredging Works
13.2.2.1
As discussed in Section 8, the Project is located
within the Yan Chau Tong Marine Park and next to the seagrass bed. The
ecological surveys conducted have concluded that the ecological value of the
seagrass bed is High (see Section 8.4.4
for the ecological evaluation). The seagrass bed is sensitive to any suspended
solids that may be generated during the construction phase of the Project.
13.2.2.2
In order to avoid any adverse
water quality impacts and hence ecological impacts on the seagrass bed in close proximity to the Project, the design has been very
mindful on the configuration and design of the pier. According to the proposed
design, open sea dredging works would be totally avoided during the
construction phase. By avoiding open sea dredging works, any adverse water
quality impacts and hence impacts on marine ecological resources during the
construction phase would be minimised as much as practicable.
13.2.3 Avoidance of Wastewater / Effluent Discharge During both Construction and Operational Phases
13.2.3.1
Given that the Project is within
the Yan Chau Tong Marine Park which is a Water Sensitive Receiver (see Section 5.3), it is important to
implement all practicable measures to avoid any discharge of waste water /
effluent discharge into Yan Chau Tong Marine Park during both the construction
and operational phases.
13.2.3.2
During the construction phase,
the potential impacts that would be generated by the construction team has been
assessed in detail (see Section 5.4.2).
The Contractor will be prohibited to discharge any wastewater and effluent into
the Yan Chau Tong Marine Park. Any wastewater and effluent that would be
generated during the construction activities would be transported away for
proper treatment and disposal.
13.2.3.3
During the operational phase, the
Project has been designed to avoid any need for using detergents/chemicals
during routine maintenance (see Section
5.5). This would therefore avoid any potential water quality impacts on the
Yan Chau Tong Marine Park.
13.2.4
Avoidance of Solid
Pier Design
13.2.4.1 The Project is located at the eastern coastal area of Crooked Harbour near Lai Chi Wo. The cove is partly surrounded by the natural terrain with a wide coastal inlet of about 800m.
13.2.4.2 The existing pier is a straight solid concrete structure. In order to minimise any additional impacts caused by the proposed pier improvement works, the structure of the proposed pier would adopt concrete decks on top supported by piled foundation. The proposed pier is extending from the existing pier towards the area with deeper water region of about -2.4mPD to the east. The diameter of the foundation would be approximately 0.8m to 1m and the column-to-column spacing is approximately 5m to 8m. Such a configuration is typical for other similar piers in Hong Kong, for instance, Sai Kung Public Pier.
13.2.4.3 Due to small footprint of the new supportive piles, changes in the flow regime and hydrodynamic in the eastern coastal area of Crooked Harbour are limited. The proposed pier improvement works have minimised any impacts on hydrodynamics as much as practicable. Details are provided in Section 5.5.
13.3 Environmental Designs Recommended to Minimise and Mitigate Environmental Impacts
13.3.1.1
Other
than initiatives to avoid environmental impacts as summarised in Section 13.2, efforts have been
exercised to minimise those inevitable impacts. The need for any environmental
designs required to mitigate the associated impacts have also been identified
and will be implemented as appropriate. A summary of these approaches is given
below.
·
Minimisation of
works in Country Park;
·
Minimisation of waste generation during construction phase;
and
·
Minimisation of construction vessels during construction
phase.
13.3.2 Minimisation of Works in Country Park
13.3.2.1
As discussed in Section 1.2, the Plover Cove Country
Park is located immediately next to Yan Chau Tong Marine Park at Lai Chi Wo.
The existing connecting walkway between the pier and the footpath to Lai Chi Wo
falls within the Country Park.
13.3.2.2
Due to the pier improvement
works, the connecting walkway made of concrete will be inevitably constructed
between the proposed LCW pier and the existing footpath to Lai Chi Wo due to
the level difference in between. The connecting walkway partly falls within the
intertidal shore of Plover Cove Country Park (PCCP) (occupied around 0.0054 ha)
as illustrated in Figure 1.3.
13.3.2.3
During the pier improvement
works, depending on the construction method to be proposed by the Contractor,
it might not be possible for the vessels to berth the existing pier, and hence
a temporary pier will then be constructed or provided to maintain the pier
operation during construction works. A temporary connecting walkway will also
need to be constructed to connect the temporary pier and the existing footpath
to Lai Chi Wo and located within the intertidal shore near the boundary of PCCP
(occupied around 0.0026 ha).
13.3.2.4
The proposed works area for two
connecting walkways has been limited (e.g. only 2m wide on each side of both
walkways would be occupied) and part of the connecting walkways falls within
the PCCP (occupied around 0.0061 ha).
13.3.2.5
Based on the ecological survey
results, the ecological values within the occupied area of intertidal shore at
the boundary of the PCCP are ranked as Low to Moderate.
13.3.2.6
The woodlands in PCCP are
important land-based ecological resources.
According to the proposed pier improvement work, all the land-based
construction activities would be limited to within 7m from the exiting
coastline. Only small and/or manual handling equipment shall be deployed to
construct the walkway, hence would totally avoid disturbance to the woodlands
and natural slope in the PCCP. Adverse ecological impact on the natural
habitats in the PCCP is not anticipated.
13.3.3
Minimisation of
Waste Generation During Construction Phase
13.3.3.1 The pier improvement works for LCW Pier endeavour to minimise the waste generation in relation to integrate the structures of the existing pier to the new pier structures. It therefore minimises the generation of over 400m3 construction and demolition (C&D) materials disposed of to the landfills/public fill banks if the whole pier was demolished and reconstructed.
13.3.3.2 The Project will limit works on land and avoids tree felling during the construction of pier. Hence, it minimises vessel trips required for the delivery of C&D materials and waste from the remoted Project site to the disposal sites. As such, disturbance from the marine vessels to the marine park can be minimised.
13.3.3.3 Section 6.3 has assessed all the practicable approaches to minimise the waste generation during the construction phase. Amongst the approaches adopted, the most effective approach is to adopt pre-cast elements for the deck as much as practicable. By adopting this approach, most of the elements for the deck would be pre-cast off-site and then transported to the site for final assembly.
13.3.4 Minimisation of Construction Vessels During Construction Phase
13.3.4.1 As open sea marine dredging would be avoided and pre-cast elements would be adopted as much as practicable, the number of construction vessels during the construction phase would also be minimised. Since the Project is located within the Yan Chau Tong Marine Park, it is inevitable that the construction vessels will travel within the marine park. Hence, by minimising the number of construction vessels required, any indirect impacts caused by those vessels on the marine park would also be minimised as well. Nevertheless, appropriate good practices would be adopted by the Contractor to operate the construction vessels.
13.4 Summary of Key Environmental Problems Avoided and Sensitive Areas Protected
13.4.1.1
Section 13.2 and Section 13.3 have summarised the key approaches adopted in the
current proposed layout to avoid, minimise and mitigate environmental impacts.
Some of these approaches have contributed to avoid a number
of environmental issues and to protect a number of environmentally
sensitive areas. Table 13.1 presents
the key environmental problems that have been avoided and any sensitive areas
protected by these approaches.
Table 13.1 Key
Environmental Problems Avoided and Sensitive Areas Protected
|
Design
Approach |
Key Environmental Problems Avoided,
Sensitive Areas Protected & Environmental Outcomes Achieved |
|
Avoidance
of open sea dredging works |
·
Adverse impacts on water quality and ecology
would be avoided. |
|
Avoidance
of wastewater / effluent discharge during both construction and operational
phases |
·
Adverse impacts on water quality would be
avoided. |
|
Avoidance
of solid pier design |
·
Adverse impacts on water quality would be
avoided. |
|
Minimisation of
works in Country Park |
·
Adverse impacts on ecology would be minimised. |
|
Minimisation of
waste generation during construction phase |
·
Generation of waste during construction
phase would be minimised. |
|
Minimisation of
construction vessels during construction phase |
·
Adverse impacts on air quality and noise
would be minimised. |
13.5 Estimated Population Protected from Various Environmental Impacts
13.5.1.1
The
Project has been carefully designed to protect the populations from various
environmental impacts. The protected populations include the following:
·
Existing
sensitive receivers of Lai Chi Wo Village would be protected from air quality
impact by implementation of mitigation measures during construction phase of
the Project.
13.6 Environmental Benefits of Environmental Protection Measures Recommended
13.6.1.1 In addition, mitigation measures/good site practices/ enhancement measures have been recommended to further reduce the environmental impacts due to construction and operation of the Project. Key recommended mitigation measures/good site practices/ enhancement measures and their associated benefits are summarised in Table 13.2 below.
|
Key recommended mitigation
measures/good site practices/enhancement measures |
Associated Benefits |
|
|
Air Quality |
·
Routing
of barges used for delivery of goods should be as far away from the
identified ASRs as practicable. ·
The number
of boat trips should be minimised as far as practicable by appropriate
planning. |
·
Protect air
sensitive receivers by reducing fugitive dust emission |
|
Noise |
·
Use of Quality Powered Mechanical Equipment
(QPME). ·
Use of temporary noise barriers to screen noise
from relatively static Powered Mechanical Equipment (PME). ·
Alternative use of plant items within one
worksite, wherever practicable. |
·
Protect noise
sensitive receivers by reducing construction noise impact |
|
Water Quality |
·
Water quality monitoring. ·
Adoption of good site practices for
foundation works, such as use of silt curtains and pile casings, to avoid and
minimise water quality impacts. ·
Excavation should
only be conducted inside pile casing. Only one grab should be used at the
same time. ·
Only 1-2 piles to be
constructed at the same time. ·
Prefabrication
construction method should be adopted as far as practicable. ·
Contractor to prepare Emergency Spillage
Plan for accidental spillage of chemicals. |
·
Protect the
neighbouring water sensitive receivers such as coral, seagrass and mangrove |
|
Waste Management |
·
Good waste management and control
practices to avoid generation of excessive amount of waste materials. ·
Employ waste collectors for
disposal of general refuse to prevent potential nuisance caused by
mistreating general refuse, such as windblown, vermin, water pollution and
visual impact. ·
Good management practices for handling and
disposal of marine sediments at dedicated marine disposal sites. |
·
Minimise
waste generation ·
Ensure
proper handling of chemical waste |
|
Land Contamination |
·
No
mitigation measures would be required. |
·
No land
contamination anticipated |
|
Ecology |
·
Seagrass monitoring ·
Pre-construction dive survey to verify the
conditions of small coral colonies on the existing LCW pier before
construction works ·
Avoidance of encroaching the trees
in particular within the country park. ·
Priority using eco-tiles or eco-concrete for
the surface of the foundation to promote seamless integration of biodiversity
into the pier design. |
·
Minimise
the impact to coral, seagrass bed and mangrove stand in proximity to the
Project ·
Protect
trees in country park ·
Enhance
biodiversity of the site |
|
Landscape
and Visual |
·
Sensitive design and disposition of the pier
structures to minimise visual intrusion to VSRs as far as practicable. |
·
Enhance the visual
appearance for the operational phase |
|
Fisheries |
·
Avoidance of mariculture
site and waters of high fisheries production ·
Adoption of good
site practices for water quality in marine works to ensure no adverse
fisheries impact would be anticipated. |
·
Protect
fisheries resources |
|
Cultural
Heritage |
·
No mitigation
measures would be required. |
·
No impact
of cultural heritage anticipated |