9.1.1
The following section presents the results of ecological assessment of
potential impacts resulting from the Project. A literature review and field
survey were undertaken to establish ecological baseline conditions and evaluate
the ecological importance of habitats/species potentially affected by proposed
works. The scale of possible ecological impacts resulting from the proposed
works was assessed and necessary mitigation measures were identified. Residual
ecological impacts were assessed, and ecological monitoring and audit
requirements were identified.
9.1.2
The assessment follows the criteria and guidelines as stated in Annexes
8 and 16 of the Technical Memorandum on Environmental Impact Assessment Process
(EIAO-TM) and the EIA Study Brief No. ESB-127/2005.
9.2.1
Guidelines, standards, documents and HKSAR Government ordinances and
regulations listed in the followings were referred to during the course of the
ecological impact assessment.
9.2.2
The Country Parks Ordinance (Cap. 208) provides for the designation and
management of country parks and special areas. Country parks are designated for
the purpose of nature conservation, countryside recreation and outdoor
education. Special Areas are created mainly for the purpose of nature
conservation.
9.2.3
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.
9.2.4
Under the Wild Animals Protection Ordinance (Cap. 170), designated wild
animals are protected from being hunted, whilst their nests and eggs are
protected from injury, destruction and removal. All birds and most mammals, including marine cetaceans, are
protected under this Ordinance. The Second Schedule of the Ordinance, which
lists all the animals protected was last revised in June 1992.
9.2.5
The Protection of Endangered Species of Animals and Plants Ordinance
(Cap. 586) restricts the import and export of scheduled species. The Ordinance
is primarily related to controlling trade in threatened and endangered species
and restricting the local possession of them.
9.2.6
The amended Town Planning Ordinance (Cap. 131) provides for the
designation of coastal protection areas, Sites of Special Scientific Interest
(SSSIs), Conservation Area, Country
Park, Green Belt or other
specified uses that promote conservation or protection of the environment. The authority responsible for administering
the Town Planning Ordinance is the Town Planning Board.
9.2.7
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. The
appendices list the legislation and administrative controls for conservation,
other conservation related measures in Hong Kong
and government departments involved in conservation.
9.2.8
Annex 16 of the EIAO TM sets 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.
9.2.9
EIAO Guidance Note No. 6/2002 clarifies the requirements of ecological
assessments under the IAO. EIAO Guidance Note No. 7/2002 provides general
guidelines for conducting ecological baseline surveys in order to fulfil
requirements stipulated in the EIAO TM.
9.2.10
List of Wild Animals Under State Protection details Category I and
Category II protected animal species under Mainland Chinese Legislation.
9.2.11
List of Wild Plants Under State Protection details Category I and
Category II protected plant species under Mainland Chinese Legislation.
9.2.12
The International Union for Conservation of Nature and Natural
Resources (IUCN) Red List of Threatened Species provides taxonomic,
conservation status and distribution
information on taxa that have been evaluated using the IUCN Red List Categories and Criteria. This system
is designed to determine the relative risk of extinction, and the main purpose
of the IUCN Red List is to catalogue and highlight those taxa that are facing a
higher risk of global extinction. The IUCN Red List also includes information
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.
Scope of Ecological Assessment
9.3.1
Existing literature documenting the ecology of the proposed works area
was reviewed. Ecology scoping survey was conducted in May 2007. The survey
covered an Assessment Area within 500
m of the works site boundary.
Literature Review
9.3.2
Previous assessment study covering the Assessment Area was reviewed.
·
Environmental
Impact Assessment Report for Planning and Development Study of Potential
Housing Site in Area 54, Tuen Mun (Environmental Resources Management, 1999)
Ecological Survey
9.3.3
A terrestrial scoping
survey was conducted in May 2007. The survey covered an Assessment Area within 500
m of the works site boundary, and comprised:
Habitat/Vegetation Survey
9.3.4
Habitat survey was
undertaken to determine the types, sizes and locations of habitats in the
Assessment Area. The habitat survey was conducted via a desktop review of
aerial photographs, base-maps and other relevant maps and plans followed by
site visits. Representative photographs of habitat types in the Assessment Area
were taken (Appendix 9.1).
9.3.5
Vegetation survey was
conducted by direct observation to record species present, relative abundance
and dominant species in different habitat types in representative parts of the
Assessment Area. The position of any plant species of conservation interest was
recorded.
Wildlife Survey
9.3.6
Fauna including
avifauna, herpetofauna, mammal and terrestrial insect (e.g. butterfly
and odonate) were surveyed in the Assessment 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.
Impact Assessment
9.3.7
Potential ecological
impacts arising from the Project were assessed following EIAO TM Annex 16
guidelines and the impacts were evaluated based on criteria in EIAO TM Annex 8.
Sites of Conservation Importance
9.3.8
There are no areas
within the Assessment Area that are of recognized conservation importance. Tai
Lam Country
Park is the nearest site
of conservation importance, 700m
to the east of the proposed works area. Tai Lam
Country Park
is the second largest country park in Hong Kong
designated in 1979. It encompasses a vast area extending from Tsuen Wan to Tuen
Mun. It provides habitats to various animals, including mammals such as Chinese
Pangolin (Manis
pentadactyla), Chinese Leopard Cat (Felis bengalensis) and Common Muntjac (Munitacus muntjac); herpetofauna like
Hong Kong Cascade Frog (Amolops
hongkongensis) and Chinese Cobra (Naja atra); and freshwater fish Rice fish (Oryzias curvinotus).
Habitat Type and Vegetation
9.3.9
A habitat map of the
Assessment Area is given in Figure 9.1.
Representative photographs of habitats are given in Appendix 9.1. Photograph of species of conservation
importance is illustrated in Appendix 9.2.
More detailed descriptions of habitats and vegetation communities in the
Assessment Area are given in the following paragraphs.
Habitat and
Vegetation
9.3.10
Habitats found within
the Assessment Area comprise of woodland, village, developed area and
watercourse. About 80% of the Assessment Area is developed area. No rare or
protected plant species was recorded within the Assessment Area. Table 9.1 lists the size of various habitat types
within the Assessment Area.
Table 9.1 Area
of Various Habitat Types within the Assessment Area
|
Habitat Type
|
Size
|
|
Woodland
|
11.6ha
|
|
Village
|
16.0ha
|
|
Developed
Area
|
123.8ha
|
|
Watercourse
|
3.4km
|
Woodland
9.3.11
A large woodland was
established behind Leung Tin
Village, Kingston Terrace and Tuen Mun
(Castle Peak) Treatment Works on the eastern
fringe of the Assessment Area. Whilst another large area of woodland habitat
was adjacent to Tuen Mun (Castle Peak) Treatment Works and Grandeur
Garden. As they distributed
near to the urban areas, they mainly comprise of plantation species, including
common exotic species such as Bauhina (Bauhina
spp.), Candlenut Tree (Aleurites moluccana),
Flame Tree (Delonix regia),
Horsetail Tree (Casuarina equisetifolia),
India-rubber Tree (Ficus elastica),
and Taiwan Acacia (Acacia confusa);
along with some common native tree species, including Big-leaved Fig (Ficus virens), Chinese Banyan (Ficus microcarpa), Elephant’s Ear (Macaranga tanarius), and Pine (Pinus spp.).
9.3.12
Fruit tree species
including Common Banana (Musa x paradisiaca),
Guava (Psidium guajava),
Jackfruit (Artocarpus macrocarpon),
Longan (Dimocarpus longan),
Mango (Mangifera indica)
and Wampi (Clausena lansium)
were recorded from woodland habitat near developed areas and villages, such as
Lei Lun Wai, Leung
Tin Village
and Tseng Tau Tsuen Chung Tsuen.
Village
9.3.13
A total of 16.0ha
of the survey area was covered by village type development at Kei Lun Wai along
Kei Tsing Street,
and several villages along San Hui of Castle
Peak Road. This habitat type was characterized by
village housing interspersed with area of vegetation. Vegetation is mainly
comprising of fruit trees, including Common Banana (Musa x paradisiaca), Jackfruit (Artocarpus macrocarpon), Longan (Dimocarpus longan), Mango (Mangifera indica) and Wampi (Clausena lansium); and some ornamental plants, such as
Hoop Pine (Araucaria cunninghamii),
Lawson's cypress (Chamaecyparis lawsoniana),
and White Jade Orchid Tree (Michelia x alba).
9.3.14
In addition, common
and widespread plant species were also recorded, including natural species
Elephant’s Ear (Macaranga tanarius)
and Pine tree; and common exotic species Candlenut Tree (Aleurites moluccana), Flame Tree (Delonix regia) and Tree Cotton (Bombax ceiba). Plant species of conservation interest
were not recorded from this habitat during the survey.
Developed Area
9.3.15
A total of 123.8ha
of developed area was recorded in the Assessment Area included roads, car
parks, residential areas, schools, hospitals (Tuen Mun Hospital and Castle Peak
Hospital), Tuen Mun (Castle Peak) Treatment Works and Lingnan University. This
habitat supports little or no vegetation aside from planted trees along the
roadside and at the fringe of buildings, including common exotic plantation
species such as Bauhina (Bauhina
spp.), Fishtail Palm (Caryota ochlandra),
Paper-bark Tree (Melaleuca quinquenervia),
Queen Crape Myrtle (Lagerstroemia speciosa),
Silk Oak (Grevillea robusta) and Sunshine Tree (Cassia surattensis).
9.3.16
Whilst, some common
ornamental plants were recorded in the developed areas especially in the
recreational parks, including Dragontree (Dracaena
marginata), Frangipani (Plumeria rubra), Hainan Elaeocarpus (Elaeocarpus hainanensis), Hoop Pine (Araucaria cunninghamii) and Rose Apple (Syzygium jambos).
9.3.17
The majority of
species present are widely distributed
in other locations in Hong Kong and not
particularly important in supporting the local terrestrial ecology. This
habitat is highly disturbed in nature with limited ecological interest. No rare
or protected plant species was recorded in the survey.
Watercourse
9.3.18
The major watercourse
recorded within the Assessment Area is the Tuen Mun River Channel. It is flowing in north-south direction and
directs the sewerage and stormwater to the sea. The channel had moderate flow
and water was appeared to be of poor to moderate quality.
9.3.19
Tuen Mun River Channel
is channelized with concrete substrate and does not support riparian
vegetation. The embankment is vegetated with mature trees and weed. Typical
plant species recorded including tree Chinese Banyan (Ficus microcarpa), Elephant’s Ear (Macaranga tanarius), and White Popinac (Leucaena leucocephala); shrub species such as Lantana (Lantana camara). Along with herb species, including
Chinese Silvergrass (Miscanthus sinensis),
Redtop (Rhynchelytrum repens),
Triste Gahnia (Gahnia tristis)
and Bidens alba
were commonly found on the embankment, whilst
Creeping Fig (Ficus pumila),
and Gairo Morning Glory (Ipomoea cairica)
was also occasionally found.
Fauna
Avifauna
9.3.20
In recent survey,
birds recorded in the Assessment Area were mainly common urban birds, including
Chinese Bulbul (Pycnonotus sinensis),
Eurasian Tree Sparrow (Passer montanus),
Japanese White-eye (Zosterops japonicus),
Oriental Magpie Robin (Copsychus saularis),
Red-whiskered Bulbul (Pycnonotus jocosus)
and Spotted Dove (Streptopelia chinensis).
Whilst individuals of Barn Swallow (Hirundo
rustica) were found at flight over the woodland
habitat. All birds are protected under the Wild Animals Protection Ordinance
(Cap.170).
9.3.21
According to Egretry Counts in 2005 and
2006 (Anon, 2005 & 2006), an active egretry can be found at about 250m
at south of the proposed works area, adjacent to San Hui Playground (Figure 9.1). In 2005, a total
of 27 nests of Little Egret (Egretta garzetta) were recorded with exotic tree
Queen Crape-myrtle (Lagerstroemia speciosa) as nesting trees.
9.3.22
To confirm the validity of literature results, recent
survey in the Tuen
Mun Egretry was conducted in August 2007 for this EIA study. Only one Little Egret was observed
resting on a tree of Albizia species in the egretry. No nesting
or breeding activities within the egretry was recorded during the recent
survey. This
finding may be due to different survey period and methodology adopted in the
recent survey. As
the egretry locates near to the urban areas, it mainly comprise of few plantation species, including Albizia sp.,
Chinese Banyan (Ficus microcarpa) and Chinese Hackberry (Celtis sinensis). During the same survey, 10 individuals of Little Egret
were found foraging at the embankment of Tuen Mun River Channel (Appendix 9.2). Little Egrets are locally very common, and the large,
secure population in Hong Kong is considered
of regional significance by Fellowes et al. (2002).
Herpetofauna and Mammals
9.3.23
During recent survey,
no herpetofauna and mammal was recorded in the Assessment Area. However,
intensive amphibian and mammal surveys in New
Territories were performed
previously (Chan & Shek, 2006; Chan et al., 2005).
9.3.24
Starting from 2002,
territory-wide surveys have also 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 Assessment 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 was recorded in the Assessment Area.
9.3.25
Referring to the
survey on the Short-nosed Fruit Bat (Cynopterus
sphinx) in urban areas in Hong Kong (Chan &
Shek, 2006), Short-nosed Fruit Bat is commonly found and widely distributed
at lower elevations in urban areas and a bat roost census was recorded this bat
in Tuen Mun. Short-nosed Fruit Bats are species of conservation importance and
protected under the Wild Animals Protection Ordinance (Cap. 170).
Terrestrial Invertebrates
9.3.26
During the recent
field survey, five butterfly species
were recorded in the Assessment Area. Three butterfly
species, including Common Mormon (Papilio polytes polytes),
Great Mormon (Papilio memnon agenor)
and Indian Cabbage White (Pieris canidia canidia)
were recorded in the village habitat; Common Grass Yellow (Eurema hecabe) was recorded in developed areas, whilst
Red-base Jezebel (Delias pasithoe
pasithoe) was found in both village and developed areas in the Assessment Area.
All recorded species are common and widespread in Hong Kong. No rare or protected species was recorded.
9.4.1
In accordance with the EIAO TM Annex 8 criteria, the ecological
importance of recorded habitats has been evaluated in Tables 9.2a-b below.
Table 9.2a Ecological Value of Woodland
and Village in the Assessment Area
|
Criteria
|
Woodland
|
Village
|
|
Naturalness
|
Mostly natural.
|
Created
habitat.
|
|
Size
|
Woodland within
Assessment Area is approximately 11.7ha.
|
Village
area within Assessment Area is approximately 16.9ha.
|
|
Diversity
|
Low to moderate floral and faunal
diversity, moderate structural complexity.
|
Low
floral and faunal diversity.
|
|
Rarity
|
No faunal and floral species of
conservation importance recorded from this habitat type during the survey.
|
No
faunal and floral species of conservation importance recorded from this
habitat type during the survey.
|
|
Recreatability
|
Moderate. Habitat characteristics and
species composition are difficult to recreate. It will take 30-50 years for
the woodland to develop.
|
N/A.
|
|
Fragmentation
|
Fragmented by urban developments and foot
paths.
|
N/A.
|
|
Ecological
linkage
|
Habitat is not structurally or functionally
linked to any high ecological value resources.
|
Habitat
is not structurally or functionally linked to any high ecological value
resources.
|
|
Potential
Value
|
Moderate.
|
Low.
|
|
Nursery
Ground
|
No record of significant nursery or
breeding ground.
|
No record of significant nursery or
breeding ground.
|
|
Age
|
30- 50 years.
|
N/A.
|
|
Abundance/
Richness of Wildlife
|
Low to Moderate.
|
Low.
|
|
Ecological Value
|
Low
to Moderate.
|
Low.
|
Table 9.2b Ecological
Value of Developed Area and Watercourse in the Assessment Area
|
Criteria
|
Developed Area
|
Watercourse
|
|
Naturalness
|
Created
habitat.
|
Created
habitat.
|
|
Size
|
Large
area of this habitat within Assessment Area is approximately 123.8ha,
the plantations were mainly along the road and in the recreational parks
within the Assessment Area.
|
The
watercourse is 3.4km
in length.
|
|
Diversity
|
Low
floral and faunal diversity, low structural complexity.
|
Low
floral and faunal diversity.
|
|
Rarity
|
No
floral and faunal species of conservation importance recorded from this
habitat during the survey.
|
One
faunal floral species of conservation importance, Little Egret (Egretta garzetta), recorded from this
habitat type during the survey.
|
|
Recreatability
|
N/A.
|
N/A.
|
|
Fragmentation
|
N/A.
|
N/A.
|
|
Ecological
linkage
|
Habitat
is not structurally or functionally linked to any high ecological value
resources.
|
Habitat
is not structurally or functionally linked to any high ecological value
resources.
|
|
Potential
Value
|
Low.
|
Low.
|
|
Nursery
Ground
|
Tuen
Mun Egretry supports a small population of Little Egrets.
|
Watercourse
supports a small population of Little Egrets.
|
|
Age
|
N/A.
|
N/A.
|
|
Abundance/
Richness of Wildlife
|
Low.
|
Low.
|
|
Ecological
Value
|
Low.
|
Low.
|
9.4.2
Woodland habitat within the Assessment Area was considered of low to
moderate ecological value because of low to moderate floral and faunal species
diversity and moderate structural complexity.
9.4.3
Village habitat was considered of low ecological value, because of low
floral and faunal diversity and most of the species identified are common,
widespread and typical of such habitat in Hong Kong.
9.4.4
Developed area was highly modified habitat supporting low diversity of
plants and animals, and most of the species identified are common, widespread
and typical of such habitat in Hong Kong. This
habitat was considered of low ecological value.
9.4.5
Watercourse in the Assessment Area was typical of Hong
Kong drainage channel. This habitat was considered of low
ecological value, as they only supported a low faunal and floral diversity.
Despite the presence of animal species of conservation interest was recorded.
9.4.6
In accordance with the EIAO TM Annex 8 criteria, the species of
conservation interest are evaluated in Tables 9.3 below.
Table 9.3 Evaluation of Faunal Species of Conservation Interest Recorded within
Assessment 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] RC – Regional Concern (Habitat loss/damage in
Hong Kong would pose significant threat to regional survival); PGC – Potential
Global Concern (Large, secure populations in Hong Kong
are of global significance). 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)
Identification and Prediction of Ecological Impacts
9.5.1
The proposed works under this Project would be widening of TMR at Tsing
Tin Interchange from a dual two-lane to dual three-lane arrangement.
9.5.2
Potential ecological impacts resulting
from construction and operation phase activities of the proposed works have
been identified, and are outlined in the following paragraphs.
Construction Phase
Direct
Impacts
9.5.3
No direct impact on ecological important habitats, such as woodland
habitat, would be resulted from the proposed works. All the proposed works
would be conducted within the developed area where mainly comprises of Tuen
Mun Road at Tsing Tin Interchange and the Castle
Peak Road (San Hui) Park. The area of directly
affected developed area is approximately 3.6ha.
9.5.4
Tree survey report prepared under this Project revealed that some trees
along the road side of the road widening section and within the Castle Peak
Road (San Hui) Park, dominated by Cuban Bast (Hibiscus tiliaceus) and Taiwan
Acacia (Acacia confusa), were recorded within the footprint of the proposed
works areas and would be directly affected by widening of Tuen Mun Road at
Tsing Tin Interchange. Tree removal (felling or transplanting) would be
required.
Indirect
Impacts
9.5.5
Noise, generated during road widening, road paving, and construction of
noise barrier, would cause disturbance to the wildlife inhabiting surrounding
areas and areas within the proposed works area.
9.5.6
Potential impacts arising from the construction stage would include the
generation of construction dust. It is anticipated that dust would be generated
mainly from piling, excavation, filling and backfilling, materials handling,
mini pile foundation works for noise barriers, wind erosion from the site and
general construction works for the widening of Tuen
Mun Road and the proposed noise barrier. Dusts
covering leaves could lead to lethal/non-lethal impacts due to a reduction in
photosynthetic rates, abrasion and blocking of stomata.
9.5.7
Indirect impacts to habitats and associated fauna adjacent to proposed
works areas could also result from increased human activities/disturbance. The
nearest natural habitat is the woodland adjacent to Tuen Mun (Castle Peak)
Treatment Works and Grandeur
Garden, 50m
on the east of the proposed works area. Potential disturbance may include the
avoidance of this woodland and reductions in wildlife density.
9.5.8
Site runoff and drainage from the proposed works area of Tuen
Mun Road widening works, if uncontrolled, would
enter Tuen Mun River Channel causing potential water quality impact and hence
impacts to the wildlife inhabiting, such as Little Egret.
9.5.9
Increased siltation could impact aquatic communities in the River
Channel adjacent the proposed works areas. Increased siltation would have a
number of adverse effects on aquatic communities. In addition to direct
physical damage (particularly to small invertebrate taxon) caused by larger
particles (e.g. sand/gravel), small particles (e.g., silt) can clog the
respiratory and feeding organs of invertebrates.
Operation Phase
9.5.10
Noise barrier is an effective mitigation measures for noise impact from
heavy traffic in the operation phase. In order to minimize the visual impact
caused by the barrier, transparent panels are preferred as concrete ones would
block views and light. However, it was reported that transparent noise barrier
would cause bird collision and hence bird mortality. As the transparent panels
would appear invisible to birds or mirrors the facing landscape, birds are
unable to recognize them as physical barriers. Hence, noise barrier with
transparent panels implemented in the operation phase would cause potential
bird mortality.
Evaluation of Ecological Impacts
9.5.11
Potential ecological impacts to habitats in the Assessment Area
resulting from the proposed works have been evaluated according to Table 1 of
Annex 8 of the EIAO TM. The evaluation are summarised in Tables 9.4a-b below.
Table 9.4a Overall Impact Evaluation of Woodland and Village
|
Evaluation Criteria
|
Woodland
|
Village
|
|
Habitat
quality
|
Low
to Moderate.
|
Low.
|
|
Species
|
No
rare floral and faunal species recorded during the survey.
|
No
rare floral and faunal species recorded during the survey.
|
|
Size/Abundance
|
No
direct impact to such habitat by the proposed works.
|
No
direct impact to such habitat by the proposed works.
|
|
Duration
|
Indirect impact to the woodland habitat is short
term.
|
Indirect impact to the village is short
term.
|
|
Reversibility
|
Indirect impact to the woodland habitat is reversible and temporary.
|
Indirect impact to the village is reversible and temporary.
|
|
Magnitude
|
Minor.
|
Minor.
|
|
Overall Impact Conclusion
|
Low.
|
Very Low.
|
Table 9.4b Overall Impact Evaluation of Developed
Area and Watercourse
|
Evaluation Criteria
|
Developed
Area
|
Watercourse
|
|
Habitat
quality
|
Low.
|
Low.
|
|
Species
|
One
bird species of conservation importance (Little Egret, Egretta garzetta) recorded from this habitat type.
|
One bird species of
conservation importance (Little Egret, Egretta
garzetta) recorded from this habitat type.
|
|
Size/Abundance
|
Direct
impact to approximately 3.5ha
of developed area by the proposed works.
Tree removal would be required.
|
No direct impact to
such habitat by the proposed works.
|
|
Duration
|
Direct impact
would be permanent.
Indirect impact to the adjacent developed area would be short
term.
|
Indirect
impact to the watercourse is short term.
|
|
Reversibility
|
Direct
impact would be irreversible.
Indirect impact to the adjacent developed area would be
reversible and temporary.
|
Indirect
impact to the watercourse is reversible and temporary.
|
|
Magnitude
|
Moderate.
|
Minor.
|
|
Overall Impact Conclusion
|
Low.
|
Low.
|
Construction Phase
Impacts
to Habitats
9.5.12
No direct impact on ecological important habitats, such as woodland
habitat, would be resulted from the proposed works. The proposed construction
works would only be conducted in the developed area where mainly comprises of Tuen
Mun Road at Tsing Tin Interchange and the partly Castle
Peak Road (San Hui) Park adjacent to and below the
Tsing Tin Interchange. Due to the heavy traffic flow, traffic noise and high
human disturbance, both of these developed areas do not function as potential
nursery or breeding grounds of the wildlife, and was not structurally or
functionally linked to any high ecological value resources, such as woodland
habitat. Meanwhile, Tuen Mun Road
at Tsing Tin Interchange and the Castle
Peak Road (San Hui) Park are man-made habitat, only
with plantation of some roadside tree species. Hence, the impact on the habitat
loss of developed area of low ecological value in the Project is considered
low.
Impacts
to Vegetation
9.5.13
Some roadside trees located within the proposed works area would be
directly impacted by widening of Tuen
Mun Road at Tsing Tin Interchange, associated earth
retaining structure and construction of access routes. Although removal of
trees would be required, all of the affected species are widespread and are not
protected or threatened in Hong Kong. The
potential loss of these individuals is considered minor. Nevertheless, such
impact would be mitigated by transplanting and compensatory planting after the
construction works.
Disturbance
Impacts
9.5.14
Indirect impacts to habitats and associated communities adjacent to the
proposed works area, especially the woodland 50m
on the east of the proposed works area, would result from increased human
activities/disturbance during the construction phase. Such impacts could arise
from noise-generating machinery during road widening, road paving, and
construction of noise barrier, and general increases in human activity. With
the implementation of effective mitigation measures, construction phase disturbance
to the adjacent woodland habitat and the wildlife inhabiting would be
relatively minor in scale. Wildlife within the proposed works area and the
adjacent woodland also adapted to high levels of human disturbance, heavy
traffic flow and traffic noise, thus the disturbance impact is considered low.
Dumping/Dust
Deposition
9.5.15
Impacts resulting from improper dumping of construction
materials/wastes and deposition of dust on vegetation adjacent to works areas
can be avoided and minimized to acceptable levels through the implementation of
standard good site practice.
Sedimentation/Water
Quality Impacts
9.5.16
Sediment and runoff if uncontrolled, would carry pollutants (adsorbed
onto the particle surfaces) into Tuen Mun River Channel in the vicinity of the
proposed works area. Mitigation measures would be implemented to control
construction site runoff and drainage from the proposed works area, and to
prevent runoff and drainage water with suspended solids from entering nearby
River Channel. With the implementation of adequate construction site drainage
and provision of sediment removal facilities, it is anticipated that
unacceptable water quality impacts on the River Channel would not arise.
Impacts
to Fauna
9.5.17
One avifauna species of conservation importance, Little Egret, was
recorded during the survey. It was recorded from the Tuen Mun egretry and the
embankment of Tuen Mun River Channel.
Potential ecological impact would be disturbance impact to nesting and
breeding activities of this species of conservation importance utilising the
egretry by noise generating construction works and increased human activities
during the construction phase. Considering that the Tuen Mun Egretry is located
in highly urbanised areas with high level of noise from the nearby existing heavy
traffic flow, Little Egret utilising the egretry for nesting and breeding
activities could tolerate certain degree of disturbance and therefore such
impact is considered as low. In addition, with the implementation of effective
mitigation measures, construction phase noise disturbance to the Little Egret
utilising the egretry for breeding and nesting activities would be minimised.
9.5.18
In addition, another probable impact to Little Egret would be the
adverse water quality of the River Channel and impacts to the fish inhabiting.
It would hence affect the feeding habitat of this wetland dependent species.
With the implementation of adequate construction site drainage and provision of
sediment removal facilities, unacceptable water quality impacts on the River
Channel would not be resulted and potential impact to Little Egret would be
minimized.
Besides, there are
alternative similar foraging habitats for Little Egret available along the Tuen
Mun River Channel. Hence this construction phase impact on the Little Egret
populations is considered as low.
Operation Phase Impacts
9.5.19
Noise barrier with transparent panels implemented in the operation
phase would cause potential bird mortality. As the transparent panels would
appear invisible to birds or mirrors the facing landscape, birds are unable to
recognize them as physical barriers. With bird-friendly design of noise
barriers, such as using non-glaring and tinted materials, putting falcon
stickers on the transparent panels, the bird collision due to the noise barrier
would be minimized.
9.6.1
As discussed in Section 2 of this Report,
only one project “Traffic Improvements to Tuen Mun Road Town Centre Section” (under Study Brief No. ESB-161/2006,
hereinafter to be referred to as “Project A”) has been confirmed at
the time of writing to coincide with the proposed Tuen
Mun Road improvement works. Project A would involve the
widening of Tuen Mun Road
from Yan Oi Square
to Wong Chu Road
Interchange and construction of a flyover from Tsing Hoi Circuit
to Tuen Mun Road Kowloon
bound. Proposed works area of Project
A locates approximately 500m
to south of the proposed works area in this Project. The anticipated
commencement date for Project
A
would be September 2008, which would be
concurrent with this Project which is scheduled from early 2008 to end 2009.
9.6.2
Project A is not anticipated to directly
impact high-valued ecological habitats (i.e. woodland habitat) and other area
of conservation interest such as the Tuen Mun Egretry in Assessment Area of this
Project. However, construction phase activities have the potential cumulative
air quality, noise and disturbance impact to the nearby habitats, including
woodland, village and developed area as well as the Tuen Mun Egretry on the
southern fringe of Assessment Area. Considering that the proposed works areas
of the two projects are far away (500m)
from each other with only a short overlapping working period, and also the affected habitats and the
egretry are already subjected to high level of human disturbance, cumulative impacts
resulting from the two projects are expected to have only temporary and minor
ecological impact.
9.7.1
Under this project, construction
activities include all small-scaled works, such as road widening, road paving
and construction of road barriers. Following EIAO-TM Annex 16 guidelines,
mitigation measures are discussed in this section to avoid, minimise and
compensate for identified ecological impacts.
Avoid
9.7.2
Construction activities would be
confined to developed areas of low ecological value, and there would be no
direct impact to other habitats within the Assessment Area.
Minimise
9.7.3
As Tuen Mun egretry is located 250
m from the proposed work area of this project, proper mitigation
measure would be implemented to
minimize disturbance impact to this egretry and also other adjacent wildlife due to the increased background
noise and human activities during the construction works. The measures include the following:
9.7.4
During the construction phase,
noise mitigation measures, including use of quiet mechanical plants and
operation of well-maintained plant, would be adopted wherever possible to
minimize such noise impact. Noise-emitting construction plant would be installed
away from the egretry as far as practical. In addition, noise-generating
construction activities with high disturbance impact would be carefully
scheduled to avoid the breeding seasons of the ardeids (i.e. mid March to
August) to the maximum practical extent.
9.7.5
Noise barrier would also be
implemented to mitigate the noise impact in operation phase. Precautionary and bird-friendly approach to noise barrier design would be adopted and
would include:
l
The
transparent materials of the noise barriers would be non-glaring and not
light-reflective;
l
Noise barrier panels would be with either tinted
materials, embedded opaque stripes or superimposed patterns of thin opaque
stripes; and
l
Noise barrier would be made visible to birds, such as
putting falcon stickers on the transparent panels.
9.7.6
Implementing such measures would
mitigate noise disturbance impact to the nearby egretry as well as other
associated wildlife adjacent to the proposed works area during both
construction and operation phases of the project. Detailed mitigation of noise
impact is shown in Noise Impact Section (Section 4).
9.7.7
Standard good site practice measures
would also be implemented in construction phase to minimize disturbance impact
to habitats and associated wildlife close to the proposed work areas, which
include:
l
Placement of equipment in designated works areas
selected on existing disturbed land;
l
Construction activities would be restricted to the
proposed works area that would be clearly demarcated;
l
The proposed works area would be reinstated immediately
after completion of the works;
l
Open burning on proposed works sites is illegal, and
will be strictly enforced;
l
Waste skips would be provided to collect general refuse
and construction wastes. The wastes would be disposed of timely and properly
off-site; and
l
Any soil contamination with fuel leaked from
construction plants should be removed off-site.
9.7.8
To minimize construction dust
impact to the vegetation within and in vicinity of the proposed works area, a
number of practical measures would be implemented, comprising the use of
regular watering, with complete coverage of any aggregate or dusty material
storage piles, and the minimum practical height for dropping of excavated
material. Detailed mitigation of construction dust impact is shown in Air
Quality Impact Section (Section 3).
9.7.9
To minimize the indirect impacts to
the nearby Tuen Mun River Channel during construction works, by controlling
construction site runoff and drainage from the proposed works area, any runoff
and drainage water with high level of suspended solids would be prevented from
entering the River Channel. Site runoff would 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 would be collected, handled and
disposed of properly.
Compensate
9.7.10
As far as possible, it is
recommended that implementation of compensatory planting of a ratio not less
than 1:1 ratio in terms of quality and quantity within the site. Detailed
compensatory plan is shown in Landscape and Visual Impact Section (Section 10).
9.8.1
With the proposed mitigation measures
in place, no adverse residual impacts resulting from the construction and
operation works of Tuen Mun Road widening works is expected.
9.9.1
The potential ecological impacts
from the Project are considered minor in this assessment and no ecological
monitoring programme would be required. Nevertheless, it is recommended that
regular environmental audit would be needed to check the implementation of
proposed mitigation measures and to ensure no adverse ecological impacts would
be resulted from the proposed development of the Project.
9.9.2
An Environmental Monitoring and
Audit (EM&A) programme is recommended to be established to check compliance
with legislative requirements. All the recommended mitigation measures should
be incorporated into the EM&A programme for proper implementation.
9.10.1
The results of ecological survey on
terrestrial ecological resources undertaken in this study identified 4 habitat
types within the Assessment Area comprising woodland, village, developed area
and watercourse. The identified woodland habitat is considered to have low to
moderate ecological value, while all other habitats, village, developed area
and watercourse are of low value.
9.10.2
One species of fauna of conservation
interest, Little Egret, have been recorded from the Tuen Mun egretry and the
embankment of the Tuen Mun River Channel in the Assessment Area. The Tuen Mun
Egretry was located in highly urbanized area with existing heavy traffic flow.
Although no nesting or breeding activities of Little Egret was recorded in
recent survey, Egretry Count in 2006 observed that this Egretry was actively
utilized by nesting Little Egret.
9.10.3
No direct impact on ecological important habitats, such as woodland
habitat, would be resulted from the proposed works. The proposed construction
works would only be conducted in the developed area where mainly comprises of Tuen
Mun Road at Tsing Tin Interchange and the partly Castle
Peak Road (San Hui) Park adjacent to and below the
Tsing Tin Interchange. These habitats are considered as low ecological value and
support no floral and faunal species of conservation importance. The impact on
habitat loss is considered as low.
9.10.4
Another key impact is the removal
of trees located within the footprint of the proposed works area. However, as
all of the trees are common and widespread plantation species, the potential
impact to the vegetation is considered low. To minimize direct loss of
individual trees, transplanting and compensatory planting, not less than 1:1
ratio in terms of quality and quantity, would be provided.
9.10.5
During the
construction phase, potential disturbance impact on nesting and breeding
activities of Little Egret utilising the egretry and water quality impact on
its feeding habitat would be resulted. With the implementation of effective
noise and water quality control mitigation measures, such disturbance impact
would be minimised. In addition, in view of the Tuen Mun Egretry is located in
highly urbanized areas with high level of noise from the nearby existing heavy
traffic flow and availability of alternative similar foraging area along the
Tuen Mun River Channel, potential impact to breeding and feeding activities of
Little Egret is considered as low.
9.10.6
Key operation phase impact is the
potential bird mortality due to the transparent noise barrier for traffic noise
impact. With
bird-friendly design of noise barriers, such as using non-glaring and tinted
materials, putting falcon stickers on the transparent panels, the bird collision
due to the noise barrier would be minimized.
9.10.7
Overall, considering the small
scale of proposed construction works, highly disturbed nature of the Assessment
Area and with the proposed mitigation measures in place, no adverse ecological
impacts resulting from the construction and operation of the project is
expected.
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