|It is our policy to
incorporate environmentally friendly features into new
or upgrading projects wherever possible. The features
provide greenery in the countryside, restore or compensate
for disturbed habitats and preserve valuable freshwater
ecosystems. As a result of our commitment and actions,
works in the past decade have cumulated into large tracts
of vegetated river banks, preserved meanders, wetland
features and mangrove habitats.
Ecological and landscape improvement measures are usually
derived from EIAs of new projects, while we also advocate
good ecological practices amongst our engineers through
circulation of guidance notes.
Our effort has
2 major river training projects namely
Yuen Long Bypass Floodway, and Construction of San Tin Eastern
Main Drainage Channel are notable examples of habitat creation.
Works were in progress in 2003. These projects will respectively
create 7.9 and 3.7 hectares of wetland habitats.
Long Bypass floodway is a new channel constructed
to divert storm water from south east of Yuen Long into
Kam Tin River to reduce flood risk in Yuen Long town
centre and other lower lying areas.
To promote biodiversity, this flood defence works will
incorporate two major ecological features ¡V a created
wetland and in-channel shallow ponds.
Several fallow fish ponds in the North of the confluence
of the Bypass Floodway and Kam Tin River will be enriched
to become 7.9 ha of wetland,
comprising 6.4 ha of marshes of varying depths and 1.5
ha of reedbed.
depths sustain a diversity of ecological niches. The
deeper marsh provides habitat for large fishes and the
associated bird community, while the shallower submerged
marsh will be ideal to become foraging grounds for wading
birds. Planting of marsh vegetation will jump start
the plant establishment process which will lead to colonisation
of the wetland by insects, aquatic invertebrates, fishes,
amphibians, reptiles and birds. The biodiversity of
the created wetland will thus be a quantum leap from
that of the original fishponds.
The reed bed will
take the flow of the channel over a mass of artificial
boulders that acts as a biofilter to break down organic
matter. The reed bed further serves as an effective
purifier that assimilates nutrients. Passage of flow
over the boulder area and reed bed gives a steady supply
of clean water to the marshes.
Two bat roosts will also be constructed in the wetland to
encourage habitation by this type of flying mammal.
animal life attracted to the YLBF wetland will include damselflies,
spotted narrow-mouth frog (Kalophrynus pleurostigma),
bats such as Japanese Pipistrelle, birds both resident and
visitors such as egrets, pond heron, Stints, and the endangered
Shallow pond feature
To promote and sustain stream life, 350 m of channel bed or
about 1.2 ha of the floodway will take the form of shallow
ponds that are purposely engineered to provide habitat for
freshwater fish, amphibians and water birds. It is the first
of its kind in Hong Kong, of a man-made waterway that serves
a flood defence purpose while specially built to become a
vibrant freshwater ecosystem.
Landscape quality of YLBF is enhanced with establishment of
grass on the channel base and the inner embankment on grassing
concrete, giving a total of 6.8ha of greenery. Furthermore,
about 3,000 trees will be planted along the channel to compensate
for the loss of 400. Grass cover and trees have tremendous
environmental benefits as they reduce heat retention, provide
foliage, shades and landscape features to the water edge,
trap dustfall and increase habitat diversity and amenity value.
of this project will go a long way in providing valuable
reference for future channel engineering work to coexist
with nature conservation.
Wetland in San Tin
The San Tin Eastern
Main Drainage Channel project that aims to alleviate
flooding problems in the low-lying areas at the east
of San Tin and Ki Lun Tsuen of Yuen Long has incorporated
environmental mitigation measures including compensatory
planting, wetland creation and landscape works. It includes
establishment of 3.7 ha of wetland habitat comprising
ponds and reedbed alongside the channel. Additionally,
to facilitate vegetation development and animal foraging
and breeding, the embankment will not be lined at the
lower reaches of the San Tin Eastern Main Channel.
Another project in the area, the flood control works
to protect San Tin, has necessitated the construction
of embankments, flood pumping station and floodwater
storage ponds. As the landscape and ecological mitigation
measure, the San Tin Created Wetland was developed from
an abandoned fishpond at the junction of San Tin Tsuen
Road and Castle Peak Road, Shek Wu Wai, San Tin, Yuen
such as water lilies, sedges and Lugwigia were successful
introduced in the submerged area and water margin. The open
water and sides now support a diversity of plants, freshwater
fishes, amphibians and dragonflies.
44 species of birds including Grey Heron, Kingfishers, sandpipers,
waterhen, and Oriental Reed Warbler have been sighted since
creation of the wetland. They included resident species, winter
visitors and passage migrants.
preservation and enrichment
Much attention is given to leaving
shelter and foraging grounds for wildlife in our works to
reintegrate the channel into the natural environment. Our
endeavours are shown below.
In one of our latest projects,
the Ngong Ping Sewage Treatment Works which has now
started construction, the landscape and social setting
was studied in detail to pave way for a meticulously
designed architecture that blends seamlessly into the
new works with the surrounding
This sewage treatment
plant serves the Po Lin Monastery, Ngong Ping Village,
and the future theme village associated with the Tung
Chung Cable Car ride. In the design, most of the major
structures of the sewage treatment works will be underground
or covered. Generous planting of native woodland trees
and shrubs is specified in the landscape plan to compensate
for loss of any existing vegetation, to screen sensitive
views and to act as an environmental benefit for local
residents, workers, and visitors.
choice of architectural design and finishing of the
superstructures will adopt traditional Chinese elements
and colours interpreted in a contemporary manner to
make the sewage works inconspicuous and fit smoothly
into the landscape character of the area.
The Ngong Ping STW will also be
Hong Kong's first tertiary treatment plant that includes due
media filter and effluent disinfection by ultraviolet light.
Effluent will be reused for toilet flushing and thus help
conserve freshwater resources. Giving due regard to the fragile
ecology of the Ngong Ping highland area, the project includes
a 5.7-km pipeline system to discharge surplus effluent to
sea at Tung Wan, Lantau.