7.1.1
The following section presents the results of an assessment of potential
ecological impacts resulting from the Project. Literature review and field surveys were
undertaken to identify ecological sensitive receivers, and the ecological
importance of habitats/species potentially affected by proposed works was
evaluated. The scale of possible
ecological impacts resulting from the proposed works was assessed, and necessary mitigation measures were
identified. Cumulative impacts resulting
from this and other Projects in the area were assessed. Residual ecological impacts were assessed, and
ecological monitoring and audit requirements were identified.
7.2.1
Guidelines, standards, documents and HKSAR Government ordinances and
regulations listed in the following sections were referred to during the course
of the ecological impact assessment.
7.2.2
The Forests and Countryside
Ordinance (Cap. 96) prohibits felling, cutting, burning or destroying of
trees and growing plants in forests and plantations on Government land. Related
subsidiary Regulations prohibit the selling or possession of listed restricted
and protected plant species. The list of
protected species in Hong Kong which comes
under the Forestry Regulations was last amended on 11 June 1993 under the
Forestry (Amendment) Regulation 1993 made under Section 3 of the Forests
and Countryside Ordinance.
7.2.3
The Wild Animals Protection
Ordinance (Cap. 170) provides protection for protected wild animals against
hunting, trapping and wilful disturbance, whilst their nests and eggs are
protected from injury, destruction and removal. The Second Schedule of the Ordinance which
lists all the animals protected was last revised in June 1992.
7.2.4
Chapter 10 of the Hong Kong
Planning Standards and Guidelines (HKPSG) covers planning considerations
relevant to conservation. This chapter
details the principles of conservation, the conservation of natural landscape
and habitats, historic buildings, archaeological sites and other antiquities. It also describes enforcement issues. The appendices list the legislation and
administrative controls for conservation, other conservation related measures
in Hong Kong and Governmental departments
involved in conservation.
7.2.5
Environmental Impact Assessment
Ordinance (Cap. 499) Technical Memorandum – Annex 16 set out the general approach and
methodology for assessment of ecological impacts arising from a project or
proposal, to allow a complete and objective identification, prediction and
evaluation of the potential ecological impacts. Annex 8
recommends the criteria that can be used for evaluating habitat and ecological
impact.
7.2.6
Town Planning Ordinance (Cap. 131) provides for the
designation of coastal protection areas, Sites of Special Scientific Interest
(SSSIs), Conservation Area (CA), Country Park (CP), Green Belt (GB) or other specific
uses that promote conservation or protection of the environment. The authority responsible for administering
the Town Planning Ordinance is the Town Planning Board.
7.2.7
The IUCN Red List of Threatened
Species provides taxonomic, conservation status and distribution
information on taxa that have been globally evaluated using the IUCN Red List
Categories and Criteria. This
system is designed to determine the relative risk of extinction, and the main
purpose is to catalogue and highlight those taxa that are facing a higher risk
of global extinction (i.e. those listed as Critically Endangered, Endangered
and Vulnerable). The IUCN Red List also
includes information on taxa that are categorized as Extinct or Extinct in the
Wild; on taxa that cannot be evaluated because of insufficient information
(i.e. are Data Deficient); and on taxa that are either close to meeting the
threatened thresholds or that would be threatened were it not for an ongoing
taxon-specific conservation programme (i.e. are Near Threatened).
Scope of Ecological Assessment
7.3.1
The study area for the terrestrial ecological environment includes all
areas within 500m from the
site boundary of the land based works or the area likely to be impacted by the
Project. For aquatic ecological
environment, the study area is within 300m from the site boundary or the area likely to be
impacted by the Project. While the
Project is land based only, and the nearest marine environment is the Castle Peak Bay, which is located about 400m away from the site boundary, the Project
is unlikely to cause potential impact to the marine environment.
7.3.2
Existing literature documenting the ecology of the proposed Study Area
was reviewed. A terrestrial scoping
survey was conducted in August 2007.
7.3.3
Habitat survey was undertaken to determine the types, sizes and
locations of habitats in the Study Area. The habitat survey was conducted via desktop
review of aerial photographs, base-maps, other relevant maps and plans followed
by site visits. Representative
photographs of habitat types were taken.
7.3.4
Vegetation survey was conducted via direct observation and recording of
the presence and dominance of species in the representative habitats within the
Study Area.
7.3.5
Fauna including avifauna, herpetofauna, mammal and terrestrial insect
(butterfly and odonate) were surveyed in the Study
Area. The survey was conducted by direct
observation, listening for calling animals, searching potential micro-habitats
and searching for signs of animal activity (e.g. tracks, burrows). Species present and relative abundance of
species in different habitat types were recorded. The location of species of conservation
interest was also recorded.
7.4.1
The Works Area is located along Tuen Mun Road from San Hui Sitting-out
Area to Kam Fei Garden
(Figure 7.1A, 7.1B
& 7.1C).
7.4.2
The proposed Works Area is located within developed area, a habitat of
low ecological value, which is comprised of residential area, sports centre,
town hall, car park, market, shopping mall and schools.
7.4.3
Within the Study Area, there are agricultural areas at Wong Ka Wai, Leung
Tin Village and Tseng Tau Tsuen; shrubland/woodland at Tai Lam Country Park;
Egretry next to river channel and San Hui Playground; Tuen Mun Town Park with
man-made pond and waterfall; plantation woodland at Sam Shing Hui; Tuen Mun
River Channel; Tuen Mun container terminal and Castle Peak Beach.
Areas of Conservation Interest
Egretry
7.4.4
An active egretry of 0.13 ha
is located between San Hui Playground and the eastern bank of Tuen Mun River
Channel, which is approximately 270m
away from the northern end of the main works boundary. As the egretry is located near urban areas,
it mainly comprises of a few plantation species, including Albizia sp., Chinese Banyan (Ficus
microcarpa) and Chinese Hackberry (Celtis
sinensis). Little Egret is locally
very common, and the large, secure population in Hong Kong
is considered to be of regional significance by Fellowes et al. (2002).
Tai Lam Country Park
7.4.5
The eastern side of the Study Area is bounded by approximately 67 ha of Tai Lam Country Park.
The Park occupies 5,370 ha of forested land and was designated
in 1979.
7.4.6
The flora species at Tai
Lam Country
Park are diverse. The
most common species include Taiwan Acacia (Acacia
confusa), Brisbane Box (Lophostemon
confertus), Chinese Red Pine (Pinus
massoniana), Slash Pine (Pinus
elliottii), Swamp Mahogany (Eucalyptus
robusta) and Paper-Bark Tree (Melaleuca leucadendron). Oak, Machilus
species, Ivy Tree (Schefflera octophylla),
and Castanopsis (Castanopsis fissa)
are also abundant.
Habitat Type and Vegetation
Table
7.1 Habitat Type within the Study Area
|
Habitat Type within
the Study Area
|
Size
|
|
Woodland
|
5 ha
|
|
Shrubland
|
67 ha
|
|
Inactive / Active agricultural
area
|
2 ha
|
|
Plantation woodland
|
5 ha
|
|
Town park
|
12 ha
|
|
Developed area /
Village
|
583 ha
|
|
Watercourse
|
Streams: 4.6 km / River channel:
12 ha
|
Woodland
7.4.7
A dense woodland of 5 ha
was found on a slope surrounding the Tuen Mun East Fresh Water Service
Reservoir. There was also an undergrowth
of shrub. Flora species recorded include
Elephant's Ear (Macaranga tanarius), Lebbek
Tree (Albizia lebbek), Desmos (Desmos chinensis), Aporusa (Aporusa chinensis) and Microcos (Microcos paniculata). Species recorded
were all common and widespread in Hong Kong.
Shrubland
7.4.8
A shrubland habitat of 67 ha
was located at the east of the Study Area at Tai Lam Country Park.
Vegetation species in this habitat
include Taiwan Acacia (Acacia confusa),
Brisbane Box (Lophostemon confertus),
Chinese Red Pine (Pinus massoniana),
Slash Pine (Pinus elliottii), Swamp
Mahogany (Eucalyptus robusta) and
Paper-bark Tree (Melaleuca leucadendron).
The species present were all common and
widespread in Hong Kong.
Inactive / Active Agricultural Area
7.4.9
Agricultural areas (2 ha)
were found in patches around villages including Wong Ka Wai, Leung Tin Village and Tseng Tau Tsuen. Species found in this habitat include Papaya (Carica papaya), Banana (Musa paradisiaca), Jackfruit (Artocarpus heterophyllus), Longan (Dimocarpus longan), Wampi (Clausena lansium) and species in the Araceae family. They are all common species in the
agricultural areas in Hong Kong.
Plantation Woodland
7.4.10
With a size of 5 ha,
the plantation woodland was located on a small hill at Sam Shing Hui. It was made up of species such as Bambusa species, Bauhinia species, Chinese Fan Palm (Livistona chinensis), Flamboyant (Delonix regia) and Morning Glory (Ipomoea cairica). The
species recorded were all common and widespread. No species of conservation importance were
identified.
Town Park
7.4.11
Tuen Mun Town
Park covered 12 ha of land and has more than 2,000
trees and 100,000 shrubs of about 200 various species. It also has a man-made lake and other
recreational facilities. It was a developed, artificially
created and managed plantation habitat with constant human disturbances.
Developed Area / Village
7.4.12
Developed area and villages occupy 583 ha of land, which made up the majority of the Study
Area. Vegetation was scarce at the Works
Area and was usually in the form of roadside and amenity plantation. The fifty-nine plant species identified around
and among the Works Area are common and widespread in Hong
Kong. No protected species were found.
7.4.13
There were villages at Wong Ka Wai, Leung Tin Village and Tseng Tau Tsuen. This habitat was composed of village housing
interspersed with patches of vegetation. Vegetation was mainly comprised of fruit tree species
as discussed in Section 7.4.9 (Agricultural Area), and some ornamental plants
such as Hoop Pine (Araucaria cunninghamii),
Lawson's Cypress (Chamaecyparis
lawsoniana), and White Jade Orchid Tree (Michelia alba) were identified.
Watercourse
7.4.14
The major watercourse recorded within the Study Area was the Tuen Mun
River Channel. It flowed from north to south
and led the collected sewerage and water into the Tuen Mun Typhoon Shelter. The channel had moderate flow and the water
appeared to be of poor to moderate quality.
7.4.15
Tuen Mun River Channel (12ha)
was channelised with concrete banks and did not support riparian vegetation. The embankment was vegetated with planted mature
trees and weed. Typical plant species
recorded include tree species such as Chinese Banyan (Ficus microcarpa), Elephant’s Ear (Macaranga tanarius) and White Popinac (Leucaena leucocephala); shrub species such as Lantana (Lantana camara); herb species such as
Chinese Silvergrass (Miscanthus sinensis),
Redtop (Rhynchelytrum repens), Triste
Gahnia (Gahnia tristis) and Bidens alba. Creeping Fig (Ficus pumila) and Gairo Morning Glory (Ipomoea cairica) were also occasionally found.
7.4.16
Some streams / rivers (approximately 4.6 km in total) were also found
flowing from Tai Lam Country
Park to the Study Area,
where most of them are natural and of good water quality.
Fauna
Avifauna
7.4.17
In a recent survey, birds recorded around the Study Area were mainly
common urban birds: Chinese Bulbul (Pycnonotus
sinensis), Eurasian Tree Sparrow (Passer
montanus), Japanese White-eye (Zosterops
japonicus), Magpie Robin (Copsychus
saularis), Red-whiskered Bulbul (Pycnonotus
jocosus) and Spotted Dove (Streptopelia
chinensis). Barn Swallow (Hirundo rustica) was found at flight
over a nearby woodland habitat. All
birds are protected under the Wild
Animals Protection Ordinance (Cap.170).
7.4.18 During
our field survey, ten individuals of Little Egret (Egretta garzetta), a species of conservation importance, were found
foraging along the embankment of Tuen Mun River Channel, where one was spotted on a Lebbek Tree (Albizia lebbekk). No nesting or breeding activities within
the egretry were
observed during the survey. Little Egret is
locally very common, and the large, secure population in Hong
Kong is
considered to be of regional significance by Fellowes et al. (2002). As the egretry locates near to the urban areas,
it mainly comprises of few plantation species,
including Albizia sp., Chinese Banyan
(Ficus microcarpa) and Chinese Hackberry (Celtis sinensis).
7.4.19
According to the Hong Kong Biodiversity (2007) and HWBWS (2005). 27 and
16 nests of Little Egret (Egretta
garzetta) were recorded nesting at the Tuen Mun Egretry in 2005 and 2006
respectively.
Herpetofauna and Mammals
7.4.20 During the
recent survey, no herpetofauna or mammal was recorded in the Study Area.
7.4.21 Starting
from 2002, territory-wide surveys have been conducted by the Herpetofauna
Working Groups of AFCD (Chan et al.
2005). Referring to these previous
surveys, two species of amphibians were recorded in the Study Area, including
Brown Tree Frog (Polypedates megacephalus)
and Gunther’s Frog (Rana guentheri). Both amphibian species recorded are very
common and widely distributed in Hong Kong. No rare or protected herpetofaunal species
were recorded in the Study Area.
7.4.22
Amphibians including Green Cascade Frog (Rana livida), Asiatic Painted Frog (Kaloula pulchra pulchra) and Hong Kong Cascade Frog (Amolops hongkongensis); reptiles such as
White-spotted Slug Snake (Pareas
margaritophorus), Bicoloured Stream Snake (Opisthotropis lateralis) and Changeable Lizard (Calotes versicolor), have been previously
recorded in Tai Lam Country Park.
7.4.23
According to Chan and Shek (2006), a roost of Short-nosed Fruit Bat (Cynopterus sphinx) was recorded near the
Study Area. It is a species of
conservation importance and is protected under the Wild Animals Protection Ordinance (Cap. 170).
7.4.24
It has been reported that Chinese Pangolin (Manis pentadactyla) and Chinese Leopard Cat (Felis bengalensis) were recorded within the Tai
Lam Country
Park, who are both listed in Wild
Animals Protection Ordinance (Cap. 170); Red Muntjac (Muntiacus muntjac) is another species that has been recorded in the
Country Park.
Terrestrial Invertebrate
(Butterfly and Dragonfly)
7.4.25
During the recent field survey, no terrestrial
invertebrate was recorded in the Assessment Area.
7.4.26
According to the “EIA-142/2007 – Widening of Tuen Mun Road at Tsing Tin Interchange” Project, which is
340m from this Project, five butterfly species were recorded in the Assessment
Area. Three butterfly species, including
Common Mormon (Papilio polytes),
Great Mormon (Papilio memnon) and
Indian Cabbage White (Pieris canidia)
were recorded in the village habitat; Common Grass Yellow (Eurema hecabe) was recorded in developed areas, whilst Red-base
Jezebel (Delias pasithoe) was found
in both village and developed areas in the Study Area. All recorded species are common and widespread
in Hong Kong.
No rare or protected species was recorded.
7.5.1
In accordance with the EIAO TM
Annex 8 criteria, the ecological importance of recorded habitats has been
evaluated in Table 7.2 below.
Table
7.2 Ecological Value of Woodland and Shrubland in the Study Area
|
Criteria
|
Woodland
|
Shrubland
|
|
Naturalness
|
Mostly natural
|
Mostly
natural
|
|
Size
|
5 ha – Woodland
habitat is small in size
|
67
ha – Shrubland habitat is moderate in size
|
|
Diversity
|
Moderate diversity and complexity
|
Moderate
diversity and complexity
|
|
Rarity
|
No rare species were recorded during
survey
|
No
rare species were recorded during survey
|
|
Recreatability
|
Moderate. It would take more than 30
years mature.
|
Moderate.
It would take several years to mature.
|
|
Fragmentation
|
Fragmented as surrounded by urban
development
|
Not
fragmented as it was part of the Tai
Lam Country
Park
|
|
Ecological
linkage
|
A small section of woodland was
connected to Tai
Lam Country
Park
|
This
habitat was part of the Tai
Lam Country
Park
|
|
Potential
Value
|
Moderate
|
Moderate
|
|
Nursery
Ground
|
No record of significant nursery or
breeding ground was found in the surveys
|
No record of significant nursery or
breeding ground was found in the surveys
|
|
Age
|
Over 30 years
|
Over 10 years
|
|
Abundance/
Richness of Wildlife
|
Low to moderate
|
Moderate
|
|
Ecological Value
|
Moderate
|
Moderate
|
Table 7.3 Ecological Value
of Plantation Woodland and Inactive/Active Agricultural
Area in the Study Area
|
Criteria
|
Plantation Woodland
|
Active/Inactive Agricultural Area
|
|
Naturalness
|
Artificially created
|
Artificially
created
|
|
Size
|
5 ha – plantation woodland habitat is
small in size
|
2 ha
– agricultural area is small in size
|
|
Diversity
|
Low to moderate
|
Low
|
|
Rarity
|
No rare species were recorded during
survey
|
No
rare species were recorded during survey
|
|
Recreatability
|
High. It would take several years to mature.
|
High
|
|
Fragmentation
|
Fragmented as it only covered the small
hill and was surrounded by urban area.
|
Highly
fragmented as they were areas in small patches
|
|
Ecological
linkage
|
No significant linkage was identified
|
Low
to moderate. Some are partially linked to Tai Lam Country Park.
|
|
Potential
Value
|
Low to moderate
|
Low
|
|
Nursery
Ground
|
No record of significant nursery or
breeding ground was found in the survey
|
No record of significant nursery or
breeding ground was found in the survey
|
|
Age
|
Over 20
|
N/A
|
|
Abundance/
Richness of Wildlife
|
Low
|
Low
|
|
Ecological Value
|
Low
|
Low
|
Table
7.4 Ecological Value of Town Park
and Developed Area in the Study Area
|
Criteria
|
Town Park
|
Developed Area
|
|
Naturalness
|
Artificially created
|
Artificially
created
|
|
Size
|
12 ha – town park is small in size
|
583
ha – developed area is large in size
|
|
Diversity
|
Low to moderate
|
Low
|
|
Rarity
|
No rare species were recorded during
survey
|
No
rare species were recorded during survey
|
|
Recreatability
|
High
|
High
|
|
Fragmentation
|
N/A
|
N/A
|
|
Ecological
linkage
|
Habitat is not structurally or
functionally linked to any high ecological value resources
|
Habitat
is structurally linked to Tai
Lam Country
Park
|
|
Potential
Value
|
Low
|
Low
|
|
Nursery
Ground
|
No record of significant nursery or
breeding ground was found in the survey
|
No record of significant nursery or
breeding ground was found in the survey
|
|
Age
|
Over 20 years
|
N/A
|
|
Abundance/
Richness of Wildlife
|
Low to moderate
|
Low
|
|
Ecological Value
|
Low
to moderate
|
Low
|
Table
7.5 Ecological Value
of Watercourse in the Study Area
|
Criteria
|
Watercourse
|
|
Naturalness
|
Tuen Mun River Channel was man-made and
channelised.
The streams from Tai Lam Country Park
were mostly natural.
|
|
Size
|
Total length of the streams is 4.6 km
The section of river channel covers 12
ha of the Study Area
|
|
Diversity
|
Low
|
|
Rarity
|
An active egretry of 0.13ha was
identified immediately next to the Tuen
Mun River
channel. One faunal species of conservation interest, Little Egret (Egretta garzetta), was recorded during
survey
|
|
Recreatability
|
Man-made channel: High
Natural stream: Moderate
|
|
Fragmentation
|
Not fragmented
|
|
Ecological
linkage
|
Man-made channel: not structurally or
functionally linked to any high ecological value resources
Natural stream: upper reaches flowed
though Tai Lam Country
Park
|
|
Potential
Value
|
Low
|
|
Nursery
Ground
|
Watercourse supports a small population
of Little Egret
|
|
Age
|
N/A
|
|
Abundance/
Richness of Wildlife
|
Low
|
|
Ecological Value
|
Man-made
channel – Low
Natural
stream - Low to moderate
|
7.5.2
In accordance with the EIAO TM Annex 8 criteria,
species of conservation interest are evaluated in Table 7.6 below.
Table
7.6 Evaluation of Fauna Species of
Conservation Interest within the Study Area
|
Common
Name
|
Scientific
Name
|
Conservation
Status[1]
|
Protection
Status
|
Distribution
|
|
Avifauna
|
|
Little
Egret
|
Egretta garzetta
|
PRC
(RC)
|
Listed
in Cap 170[2]
|
Common
|
Note:
[1] PRC – Potential Regional Concern. RC – Regional Concern (Habitat
loss/damage in Hong Kong would pose significant
threat to regional survival). Letters in
parentheses indicate that assessment of status is based on restrictedness of
breeding and/or roosting sites rather than general occurrence. Refer
to Fellowes et al. (2002) for further
explanation of status.
[2] Protected under
the Wild Animals Protection Ordinance
(Cap.170)
7.6.1
Potential ecological impacts
resulted from construction and operation phase activities of the proposed works
have been identified, and outlined following the EIAO TM Annex 16 guidelines; the impacts were evaluated based on criteria in EIAO TM Annex 8.
Construction Phase
Direct Impacts
7.6.2
No direct impact on ecologically
important habitats would be resulted from the proposed works. All of the proposed works would be conducted within
the developed area along Tuen Mun
Road and would take up approximately 12 ha of land. The main work site would be located at the
section between San Hui Sitting-out Area and Kam Fei Garden. The two isolated sites located at the north of
the work site have been proposed for small scale road marking work, and the
ones located to the east and west are for junction improvement works.
7.6.3
The existing roadside plantation
would be directly affected by the road widening and the construction of
flyover. Tree removal/relocation would
be required to give way to the construction works. Most species recorded were locally common
roadside plantation, including Acacia
confusa, Bauhinia blakeana, Melaleuca leucadendron and Delonix regia. No rare or protected species were recorded at
the proposed Works Area.
Indirect Impacts
7.6.4
Noise generated during road
widening and flyover construction would cause disturbance to the nearby
wildlife. Habitats that are most likely
to be affected by the construction noise include the woodland near Tuen Mun
East Fresh Water Service Reservoir, the plantation woodland at Sam Shing Hui, a
small section of Tai Lam Country Park at the southern end of the Works Area,
and the egretry which is 270m
away from the northern end of the Works Area.
7.6.5
Construction dust generated during
piling, excavating, filling, backfilling and materials handling would affect
the surrounding vegetation. Mini pile
foundation works for noise barriers, wind erosion from the site and general
construction works would also affect the surrounding environment. Construction dust could cover leaves and lead
to reduction in photosynthesis rate, abrasion and stomata blockage, thus
reducing the quality of habitat.
7.6.6
An increase in human activities
could cause indirect impacts to habitats and their associated fauna. The presence of human and their disturbance (e.g.
noise, waste) may cause the avoidance of habitats by fauna and reduction in
wildlife density within the habitat.
7.6.7
Site runoff and drainage from
the proposed Works Area would enter Tuen Mun River Channel causing degradation
of water quality if uncontrolled, hence affecting the habitat users including
aquatic fauna and Little Egret, a species of conservation importance, found at
the egretry.
7.6.8
Waste generated during
construction would temporarily occupy the nearby work sites. The accumulation of waste would cause visual
disturbance to wildlife, thus degrading the quality of their habitat.
Operation Phase
Direct Impacts
7.6.9
No potential direct impacts on ecologically important habitats have been
identified during operation.
7.6.10
Transparent noise barrier is a potential hazard to birds, as birds are
not always sensitive to their presence due to the transparency, which is
preferred by the public as concrete ones would block view and light. Direct collision sometimes occurs as birds are
unable to recognise them as physical barrier and could result in bird
mortality. Vertical barriers, cantilever
barriers and enclosure (full or semi) are proposed on most section of Tuen Mun Road. The distance between the nearest proposed barrier
and egretry is 310m.
Indirect Impacts
7.6.11 The proposed noise barrier would greatly reduce the noise from the
busy traffic along the Works Area. The
reduced level of noise would decrease the level of disturbance to the wildlife at
nearby habitats.
7.7.1
Potential ecological impacts arised from the
Project have been evaluated according to Table 1 of Annex 8 of the EIAO TM. The evaluation are summarised in the tables
below.
Table 7.7 Overall Impact Evaluation of Woodland and Shrubland
|
Evaluation
Criteria
|
Woodland
|
Shrubland
|
|
Habitat quality
|
Moderate
|
Moderate
|
|
Species
|
No species of conservation interest were recorded
in this habitat during the surveys
|
No species of conservation interest were recorded
in this habitat during the surveys
|
|
Size/Abundance
|
No direct impact to this habitat
|
No direct impact to this habitat
|
|
Duration
|
Indirect impact would be short term during
construction
|
Indirect impact would be short term during
construction
|
|
Reversibility
|
Indirect impact is reversible
|
Indirect impact is reversible
|
|
Magnitude
|
Small
|
Small
|
|
Overall Impact
Conclusion
|
Low
|
Low
|
Table
7.8 Overall Impact Evaluation of Plantation Woodland
and Inactive/Active Agricultural Area
|
Evaluation
Criteria
|
Plantation Woodland
|
Inactive
/ Active Agricultural Area
|
|
Habitat quality
|
Low
|
Low
|
|
Species
|
No species of conservation interest were recorded
in this habitat during the surveys
|
No species of conservation interest were recorded
in this habitat during the surveys
|
|
Size/Abundance
|
No direct impact to this habitat
|
No direct impact to this habitat
|
|
Duration
|
Indirect impact would be short term during
construction
|
Indirect impact would be short term during
construction
|
|
Reversibility
|
Indirect impact would be reversible
|
Indirect impact would be reversible
|
|
Magnitude
|
Small
|
Small
|
|
Overall Impact
Conclusion
|
Low
|
Low
|
Table
7.9 Overall Impact Evaluation of Town Park
and Developed Area / Village
|
Evaluation
Criteria
|
Town Park
|
Developed
Area / Village
|
|
Habitat quality
|
Low to moderate
|
Low
|
|
Species
|
No species of conservation interest were recorded
in this habitat during the surveys
|
No species of conservation interest were recorded
in this habitat during the surveys
|
|
Size/Abundance
|
No direct impact to this habitat
|
Approximately 10 ha of developed area would be
occupied by the Works Area. Removal of roadside plantation would be required
|
|
Duration
|
Indirect impact would be short term during
construction
|
Direct impact would be permanent. Indirect impacts
would be temporary.
|
|
Reversibility
|
Indirect impact would be reversible
|
Direct impacts would be non-reversible.
Tree removed could be transplanted at different locations. Indirect impacts would
be reversible.
|
|
Magnitude
|
Small
|
Moderate
|
|
Overall Impact
Conclusion
|
Low
|
Low
|
Table
7.10 Overall Impact Evaluation of Watercourse
|
Evaluation
Criteria
|
Watercourse
|
|
Habitat quality
|
Man-made channel – Low
Natural stream – Low to moderate
|
|
Species
|
One species of conservation interest, Little Egret
(Egretta garzetta), was recorded in
this habitat during the survey
|
|
Size/Abundance
|
No direct impact to this habitat
|
|
Duration
|
Indirect impact would be short term during
construction
|
|
Reversibility
|
Indirect impact would be reversible
|
|
Magnitude
|
Small
|
|
Overall Impact
Conclusion
|
Low
|
Construction Phase Impacts Evaluation
Impacts on habitats
7.7.2
No direct impact on
ecologically important habitats would be resulted from the proposed works. Works would be conducted in the developed area
which is used for schools, residential area, shopping mall and sports ground. Due to the heavy traffic flow and high level
of human disturbance, the developed area within the Study Area is not expected to
function as nursery or breeding ground for wildlife. The Works Area was not structurally or
functionally linked to any habitats of high ecological value. The impacts from the loss of developed area are
therefore considered to be low.
Impacts on vegetation
7.7.3
The roadside plantation of
common species would be directly affected by the Project. Tree removal would be required for the
construction works. Such impact could be
mitigated by transplanting and compensatory planting after the construction
works. As the species recorded are
common and widespread in Hong Kong, the impact
of vegetation loss is therefore considered to be low.
7.7.4
Dust generated during
construction could block plant surface and their stomata, thus affecting the
rate of photosynthesis. The decrease in
quality of plants and habitats would indirectly affect the associated
wildlife. Such degradation in habitat
and associated wildlife could be controlled via site mitigation and dust
reduction methods, the impacts arised from construction dust is therefore
considered to be acceptable.
Impacts from disturbance
7.7.5
Indirect impacts to habitats and associated fauna around
the proposed Works Area, especially the plantation woodland right next to the
southern end of the proposed Works Area, would be affected by an increase in
human activities/disturbance during the construction phase. Such impacts could arise from noise generated
by machines during road widening, road paving, construction of noise barrier,
and general increase in human activity. With
the implementation of effective mitigation measures, construction phase
disturbance to the nearby ecologically important habitats and the inhabitating
wildlife could be minimised. Moreover, wildlife
and plant species within the Study Area have adapted to high level of pollution
and urban disturbances. The impacts of
disturbance are therefore considered to be low.
Impacts from Waste Dumping
7.7.6
Impacts resulted from
improper dumping of construction material/waste and deposition of dust on vegetation within and near to the Works Areas can be avoided and minimised to
acceptable levels through the implementation of standard good site practice.
Impacts on Water Quality
7.7.7
Uncontrolled site runoff
would carry pollutants and sediments into Tuen Mun River Channel and eventually
into the Tuen Mun Typhoon Shelter. Mitigation
measures could be implemented to control construction site runoff and drainage
from the proposed Works Area, and to prevent runoff and polluted drainage water
from entering the river channel and the sea. With the implementation of adequate site
drainage and provision of sediment removal facilities, it is therefore
considered that impacts on water quality are acceptable.
Impacts on Fauna
7.7.8
Little Egret, a bird
species of conservation interest, was recorded at the egretry at, and along the
Tuen Mun River Channel. In Hong Kong, Little Egret is a species adapted to pollution
and disturbance. Impacts that could
affect the livelihood of egrets include construction noise, increase in the
presence of human and site runoff. Considering that the Tuen Mun Egretry is
located in highly urbanised areas with high level of noise from the nearby
existing traffic flow, and Little Egret utilising the Tuen Mun River Channel
and the egretry for nesting and breeding could tolerate a certain level of
disturbance, the impact on Little Egret is considered as low. With the
implementation of appropriate mitigation measures, such as temporary noise
barrier, careful scheduling of works, and implementing good site practice, the
noise disturbance to the Little Egret utilising the egretry for breeding and
nesting activities during the construction phase would be minimized.
7.7.9
Aquatic invertebrate and
fish at Tuen Mun River Channel could be affected by site runoff and polluted
drainage water from work sites. With the
implementation of adequate construction site drainage and provision of sediment
removal facilities, potential impact of unacceptable water quality at the River
Channel should not arise. The potential
impacts to the aquatic invertebrate and fish are considered to be low.
Operation Phase Impacts Evaluation
7.7.10 No substantial direct and indirect ecological impacts are expected to
add on to the existing impacts caused by the present operation of Tuen Mun Road.
7.7.11 The invisibility of noise barrier to all birds must be mitigated. Falcon sticker is effective in making
transparent barrier more visible to birds, thus preventing bird collision. Other practices include the use of tinted
materials, embedded opaque stripes and superimposed patterns of thin opaque
stripes, are also effective in reducing the chance of bird collision. With the combination of these measures, bird
collision could be minimised. The impact
of noise barrier on birds is therefore considered to be low.
7.7.12 The Tuen
Mun Egretry is not expected to be significantly affected during operation, as
Little Egret is adapted to human disturbance and the egretry has already been
exposed to the daily heavy traffic at Tuen
Mun Road. Noise impact on the egretry is considered to
be low as permanent noise barriers have been proposed to be constructed. Nesting activities are not expected to be
affected during operation.
7.8.1
The “EIA-142/2007 – Widening of Tuen Mun Road at Tsing Tin Interchange” Project,
hereinafter to be referred to as “Project A”. The location of the Works Area of Project A is
340m to the north of the main Works
Area of this Project. Project A would
involve the provision of an additional interchange connecting Tuen Mun Road and
Castle Peak Road near Sam Shing Estate, and widening of Tuen Mun Road at Tsing
Tin Interchange from a dual two-lane to dual three-lane arrangement. Project A commenced in June 2008 for
completion in 2010, which should concurrent with this Project which is
scheduled for commencement in end 2009.
7.8.2
Project A is not expected
to have direct impacts on high ecological value habitats. However, construction phase activities are
considered to have potential cumulative impacts from air and noise pollution on
the habitats at the northern section of the Study Area. As the proposed works areas of the two
projects are 340m away from
each other, and the proposed construction periods have a short overlapping time,
cumulative impacts resulting from the two projects are expected to have
temporary and minor ecological impact.
7.8.3
For the potential cumulative impacts on the Tuen
Mun Egretry, the overlapping time for Project A and the current Project is
short, and that impacts such as noise and site runoff could be controlled by effective
mitigation measures, cumulative impacts resulting from the two projects are expected to have temporary and minor
ecological impact.
7.9.1
Following EIAO-TM
Annex 16 guidelines, mitigation measures are discussed in this section to avoid,
minimise and compensate for identified ecological impacts.
Avoid
7.9.2
Construction activities should be confined to
developed areas of low ecological value. There should be no direct impact on other
habitats within the Study Area.
Minimise
7.9.3
Noise mitigation measures,
including installation of noise-emitting construction plant away from egretry,
careful scheduling of noisy works with high disturbance impact to avoid
breeding season of ardeid species (i.e. mid March to August) to prevent impacts
on nesting activities of Little Egret, operation of well-maintained machinery,
and use of noise reduction facilities could be implemented to mitigate noise
impacts arised from construction activities such as road widening and road
paving. Temporary noise barrier should
also be used to reduce the level of noise during construction. Noise impact would be minimised during
operation phase as permanent noise barrier has been proposed to be constructed.
The use of low noise road surfacing
could also reduce the level of noise during operation. Such measures could minimise disturbance to
habitats, including the egretry, within and adjacent to the proposed Works Area.
Detailed mitigation of noise impact is
shown in the Noise Impact section (Section 3) in this EIA report.
7.9.4
In order to minimise the
impact of construction dust to the vegetation and associated wildlife within
and around the proposed Works Area, practical measures such as regular
watering, complete coverage of dusty material storage piles, and the use of minimum
practical height for dropping excavated material should be implemented. Detailed mitigation for construction dust
impact is shown in Air Quality Impact section (Section 4) in this
EIA report.
7.9.5
Standard good site practice
measures should be implemented and should include:
•
Placement of equipment in
designated Works Areas within the existing disturbed land.
•
Construction activities should
be restricted to the proposed Works Area.
•
The proposed Works Area should
be reinstated immediately after completion of the works.
•
Open burning on proposed
works site is illegal, and will be strictly enforced.
•
Waste skips should be
provided to collect general refuse and construction wastes, which should be
disposed regularly and properly off-site.
•
Soil contaminated by fuel
leaked from construction plants should be removed and treated.
7.9.6
Mitigation measures should
be implemented to prevent and minimise the indirect impacts to the nearby Tuen
Mun River Channel by controlling construction site runoff and drainage from the
proposed Works Area. Site runoff could
be directed towards regularly cleaned and maintained sand traps, silt traps and
where appropriate, oil/grease separators to minimise risk of sedimentation and
pollution to the river channel. Debris
and rubbish generated on-site should be collected, handled and disposed properly.
7.9.7
In order to prevent and
minimise the chance of bird collision during operation phase, falcon sticker,
tinted materials, embedded opaque stripes and superimposed patterns of thin
opaque stripes are methods that could be used during the design of noise
barrier.
Compensate
7.9.8
Compensatory planting is recommended as the current roadside plantation must be
removed to give way to the works. Species
of choice should be composed of similar native species and the felling and
planting ratio should be no less than 1:1
in terms of quantity.
7.10.1 With the proposed mitigation measures in place, no adverse residual
impacts resulting from the construction and operation of TMRTCS widening works is expected.
7.11.1 The
overall potential ecological impacts from the Project are considered to be
minor. No specific ecological monitoring
programme is required. Environmental
audit is needed to ensure the ecological impacts from the construction and
operation of the Project is kept within acceptable levels, and the application and
mitigation measures are practical and effective.
7.12.1 The seven
habitat types identified within the Study Area in this ecological survey
include woodland, shrubland, plantation woodland, inactive/active agricultural
area, town park, developed area/village and watercourse. The identified woodland and shrubland habitats
are considered to have moderate ecological value, while the other habitats are
considered to have low to moderate value.
7.12.2 No direct
impact on ecologically important habitats would be resulted from the proposed
works, which would take up 12 ha
of developed area. The proposed
construction works would only occur within the developed area, which is of low
ecological value and is comprised of a section of Tuen Mun Road from San Hui Sitting-out
Area to Kam Fai Garden. The developed
area supports no floral and faunal species of conservation importance. The impact on habitat loss is considered to be
low.
7.12.3 Little
Egret (Egretta garzetta), a species
of conservation interest, has adopted to tolerate a certain level of pollution
and disturbance. It was recorded at the
egretry and along the embankment of Tuen Mun River Channel within the Study
Area. Construction and operation of the
Project are not expected to have significant impact on the egretry and bird population
with the implementation of the proposed mitigation measures.
7.12.4 The
impact of loss of vegetation through removal of roadside plantation of common
species within the proposed Works Area is not considered to be ecologically
significant. The loss could be compensated
by compensatory planting or transplantation.
7.12.5 Bird
collision with the proposed construction of permanent noise barrier could result
in bird mortality. With the combination
of the suggested measures for the design of noise barrier, bird collision due
to the noise barrier would be minimized.
7.12.6 Considering
the small scale of proposed construction works, highly disturbed nature of the
Study Area, and with the proposed mitigation measures in place, including noise
mitigation measures and good site practice, no adverse ecological impacts from
the construction and operation of the Project is expected.
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