Location and Scale of
the Project
2.1
The proposed site
is located on the eastern coast of Lung Kwu Chau as shown in Figure 2.1. The location of the existing jetty is also
shown on Figure 2.1.
Construction and
Operational Activities
2.2
The major
activities involved during the construction stage of the Project are dredging
for foundation of the jetty and catwalk, laying of rock bedding, construction
of concrete catwalk, extension of an existing footpath, dredging for approach
channel and demolition of the existing jetty.
A maximum production rate for the dredging works is 500 m3
per day, with one dredger working on-site at any time.
2.3
During the
operation stage, the only activities at the proposed jetty will be the berthing
and mooring of vessels for the purpose of servicing and maintaining the
DVOR/DME station and for emergency repair work, and infrequent maintenance
dredging of the approach channel.
2.4
The planning,
design and supervision of construction of the proposed jetty will be conducted
by CED. The construction works is scheduled
to commence in March 2003 for completion by December 2003.
2.5
It is expected
that this Project has no major interaction with other projects.
Preferred Jetty Location
and Design Option
2.6
Under the
preliminary design given in the EIA Study Brief, the Project comprises
construction of a precast concrete blockwork jetty and a concrete catwalk and
dredging of an approach channel.
Alternative jetty location and design options have been investigated and
the preliminary design has been refined from an environmental perspective. Alternative transportation modes for
servicing and maintaining the DVOR/DME station have also been assessed with
regard to their environmental benefits and disbenefits. Construction of the proposed jetty is
considered necessary as there are no other modes of transportation available
other than by sea to transport the required equipment and personnel to the
island and to provide access to facilitate emergency repair work of the
DVOR/DME Station.
2.7
In the vicinity of
the existing small jetty, two alternative locations (Options 2 and 3) have been
identified in addition to the initially proposed jetty location (Option 1 as
shown in Figure 2.1). An evaluation of
the environmental aspects of these alternative locations was undertaken with
respect to the issues of water quality/dredged sediment, ecology, archaeology
and visual/landscape.
2.8
Option 3 was
preferred after the evaluation of the environmental benefits and disbenefits of
the three options. Comparing with
Option 1, the length of the catwalk in Option 3 was substantially reduced and
the dredging area was smaller. This
would minimise the area of seabed affected by the construction activities and
the associated water quality, ecology, archaeology and visual/landscape
impacts. Option 2 is a less preferred
location for the jetty compared to Option 3.
This location has a natural shoreline, with the highest density of
intertidal organisms. Extension of a
path to this location would cause major disturbance to the coastal terrestrial
habitats owing to the need for major construction works. In addition, Option 2 is sited near the
shipwreck area to the north of the bay where soft corals are attached to the
wreck. Option 3 was preferred to Option
2 as the majority of the shore and backshore areas of Option 3 are already
exposed to significant human disturbance.
2.9
The preferred
option selected for the location of the jetty (refer to Figure 2.2)
incorporates the recommendations raised at the Marine Parks Committee meeting
held on 9 November 2001. The main
environmental benefits of the proposed jetty location are that it would require
a smaller dredging area and cause less intrusion into the bay of the adjacent
beach, and therefore would have less impact on the dolphins. Support from the Lung Kwu Tan villagers for
the preferred option has been obtained.
2.10
Based on the
preferred jetty location, the scope of the Project comprises the following:
·
construction
of a precast concrete blockwork jetty (10 m by 20 m) with a single berth;
·
construction
of a concrete catwalk (approximately 22 m long);
·
dredging
of an approach channel to a level of –2.5 mCD in front of the berth;
·
installation
of miscellaneous facilities on the jetty, including lighting, navigation light,
fendering, handrails, bollards, tide gauge, etc;
·
demolition
of the existing jetty upon completion of the proposed jetty; and
·
extension
of an existing footpath.
2.11
The environmental
benefits and disbenefits of alternative design options for the jetty have been
considered. The following design option
is preferred:
·
Adopt a blockwork structure
to eliminate the need for any piling works which would be the most significant
potential source of impact on the dolphins.
·
Use pre-cast structures to
minimise the time of construction and reduce water quality impacts.
·
Provide openings along the
bottom of the catwalk to allow seawater circulation. It is recommended that the number/size of openings beneath the
catwalk be maximized as far as practicable to allow seawater circulation.
·
Minimise overall jetty
structure to minimise dredging works and associated impacts.