Table 12.1 Summary of Key Environmental
Outcomes/Benefits and Mitigation Measures
order to cope with the anticipated increase in water demand generated from
the existing and proposed developments in North Lantau New Town, Discovery
Bay, Northshore Lantau, Ngong Ping and the International Theme Park at
Penny’s Bay, it is necessary to complete the extension work to Siu Ho Wan WTW
by the end of 2011.
options for the Siu Ho Wan Raw Water Booster Pumping Station were
considered. The proposed site located
adjacent to the Siu Ho Wan WTW was recommended and has the
following benefits: less site formation work and slope stabilization
works; no restrictions on future extension of the Siu Ho
Wan Raw Water Booster Pumping Station; more convenient in operation and
maintenance; and lower ecological impact and
options of raw water mains alignments at Pui
O were considered. The proposed alignment
along South Lantau Road was
recommended and has the following benefits: lower
ecological, landscape and visual and cultural heritage impacts; and
no private land resumption nor public land
rezoning would be required.
noise impacts from the laying of raw water mains, demolition and
reprovisioning of Pui O Raw Water Pumping Station if unmitigated, would
exceed daytime noise criterion at the
representative NSRs. Use of silenced PME and movable noise barriers was therefore
recommended. Scheduling of construction activities was proposed for mitigating noise impacts on Bui O Public School during examination
No operational noise exceedance
at the representative NSRs was predicted from operation of the Pui O raw
water pumping stations. if the recommended
noise mitigation measures are implemented.
identified in the area of Siu Ho Wan.
dust impacts would mainly be related to
construction dust from excavation, demolition, materials handling and
wind erosion. Dust
suppression methods and good site practices were proposed
protect ASRs in the vicinity of the works
areas in Siu Ho Wan and Pui O areas.
operational air quality impact would be expected.
potential water quality impact would
be related to earthworks
proposed extension of Siu Ho Wan WTW, the proposed Siu Ho Wan Raw Water
Booster Pumping Station, trench excavation for the mainlaying works at Pui O
and demolition works for Pui O Raw Water Pumping Station. The nearest identified water bodies to the
works areas at Siu Ho Wan and Pui O are the existing streams at Pui O and the
drainage channel to the north of the Siu Ho Wan WTW. Potential impacts from
construction activities would be minimized
by implementing the recommended mitigation
measures, such as control measures on runoff and
drainage from work areas to minimize construction run-off and proper site
management and good housekeeping practices.
of the proposed raw water mains at Pui O would mainly be confined to the
existing South Lantau Road.
However, both ends of the proposed
alignment would directly impact woodland habitat. Vegetation clearance for
excavation of a 2.5m wide trench would impact approximately 0.1ha of woodland
habitat. The extent of the surrounding works area within woodland habitat
would be approximately 0.4ha. Individuals of two locally common plant species of
conservation interest (the protected shrub/tree Pavetta hongkongensis
and IUCN listed tree Aquilaria
sinensis) were found scattered
throughout the woodland habitat and may be directly impacted or disturbed by the
proposed mainslaying works. Transplantation
of individual plants to a safe location within
the same habitat was proposed.
impacts, such as impacts on stream water quality due to
site runoff and disturbance to wildlife, were
predicted to be very minor with the implementation of good
ecological impact is anticipated from
the proposed works at Siu Ho Wan.
include construction & demolition (C&D) material from the earthworks
for the extension of the Siu Ho Wan WTW, Siu Ho Wan Raw Water Booster Pumping
Station and the mainlaying works along South Lantau Road at Pui O and
demolition works for Pui O Raw Water Pumping Station, general refuse from the
workforce and chemical wastes from plant and equipment maintenance. Provided
that these construction waste
arisings are handled, transported and disposed of using the recommended
methods and that good site practices are strictly followed, adverse
environmental impacts would not be anticipated during the construction works.
of archaeological findings
were identified in the Siu Ho Wan and Pui O site areas.
majority of the identified built heritage
resources are located a sufficient distance from the proposed works areas and would
not be adversely impacted. Demolition
and reprovisioning works for the Pui O Raw Water Pumping Station may restrict
access or affect the structure of a shrine at Pui O Lo Wai Tsuen. Mitigation measures in the form of a
temporary fenced-off buffer zone were recommended.
built heritage resources were identified in the
vicinity of the proposed works at Siu Ho Wan.
landscape and visual impacts would be mainly related to the removal of
existing vegetation and the proximity of the proposed structures to road
users, staff working
in nearby areas and local residents. The impacts in Siu Ho Wan and Pui O
sites would be alleviated to acceptable levels with the implementation
of recommended mitigation measures, such as
sympathetic design of structures and design of
external appearance, reinstatement of planting on disturbed land, and compensatory
study was conducted to identify additional chlorine hazards initiated by
constructions activities. Mitigation
measures were proposed, such as
monitoring and inspection of chlorine dosing facilities, management of
materials and personnel, investigation and training, for inclusion in the
Contract document and the
Safety Plan and Emergency Plan.
proposed water treatment process after the extension of Siu Ho Wan WTW would not induce any
increase of chlorine hazard in terms of storage or number of deliveries.