6.1.1
The following section presents the results of an
ecological assessment of potential impacts resulting from the Project. As
stated in the EIAO-TM, the aim of ecological impact assessment is to protect,
maintain or rehabilitate the natural environment. A literature review and field
surveys were undertaken to identify ecological sensitive receivers, and the
ecological importance of habitats/species potentially affected by the proposed
works was evaluated. The scale of possible ecological impacts resulting from
the proposed works was assessed, and necessary mitigation measures were
identified. No cumulative impacts were anticipated since no other projects were
expected to occur concurrently with the Project. Residual ecological impacts
were assessed, and ecological monitoring and audit requirements identified.
6.1.2
The Project consists of
uprating and upgrading works to water supplies infrastructure at Pui O on the
south side of Lantau Island and at Siu Ho Wan located on the northern side of
Lantau Island. The locations of these works are detailed in Figures 2.1 and
2.3.
6.1.3
At Siu Ho Wan, works would be
limited to the construction and operation of a Raw Water Booster Pumping
Station and Water Treatment Works Extension (Figure 6.1 refers). Field surveys
conducted in July and September 2003 confirmed that direct impacts resulting
from these works would be limited to the loss of small areas of existing
developed/abandoned land of very low ecological value. Indirect impacts to
habitats and communities adjacent to the proposed works areas are also
anticipated to be minimal for the following reasons:
·
No
habitats or species of conservation interest were recorded during ecological
surveys of areas adjacent to the proposed work site.
·
Areas
adjacent to the proposed works areas are already subject to moderate-high
levels of disturbance from existing water treatment works and heavy road/rail
traffic along the North Lantau Highway and Airport Express Link.
6.1.4 Because of the negligible ecological impacts anticipated at the Siu Ho Wan site, potential ecological impacts addressed in this section are limited to proposed works at the Pui O site.
6.2.1
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.
·
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.
·
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.
·
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.
·
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.
·
Chapter 10 of the 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
government departments involved in conservation.
·
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.
·
EIAO Guidance Note No. 6/2002 clarifies the requirements of
ecological assessments under the EIAO.
· EIAO Guidance Note No. 7/2002 provides general guidelines for conducting ecological baseline surveys in order to fulfil requirements stipulated in the EIAO-TM.
6.3.1
Existing literature
documenting the ecology of Hong Kong and the Pui O area in particular was
reviewed. Relevant sources included:
6.3.2
To confirm the validity of
and update existing data, ecological surveys covering the wet season were
conducted from July 2003 to October 2003. In addition, ad hoc observations of
fauna (primarily avifauna) were made during site visits conducted to the
Assessment Area in the 2003/2004 dry season. The surveys covered all areas
within 500m of the proposed works areas. The surveys comprised:
6.3.3
Habitats inside the
Assessment Areas were identified and mapped to determine the types, size and
their location. A desktop review of aerial photographs and other relevant
maps/plans were reviewed followed by surveys to verify the review. Surveys were
undertaken in the wet season (July – October 2003). Vegetation surveys were
focussed along the proposed alignment of the raw water main, with more general
surveys of other areas in the Assessment Area undertaken. Plant species,
relative abundance and growth forms were recorded. Identification of species
and status in Hong Kong were made with reference to AFD (1993), AFCD (2002) and
Corlett et al. (2000).
Avifauna Surveys
6.3.4 Avifaunal surveys of each Assessment Area were conducted on a monthly basis over 3 months, during the wet season (from July, August and September 2003) and included night survey. Species present and relative abundance of species were recorded.
6.3.5 Survey of herpetofauna and mammals was conducted to record species present by direct observation, searching potential habitats (e.g., potential bat roosts), listening for calling animals, and searching for signs of mammal activity such as burrows, scats etc. The herpetofauna/mammal surveys covered the wet (July, August and September 2003) season and were conducted during the day and night.
6.3.6 Surveys of adult butterflies and odonates were conducted in each Assessment Area, covering the wet season (July and August 2003). Species present and relative species abundance were recorded by direct observation.
6.3.7 Aquatic macroinvertebrates and fish populations of selected habitats were surveyed. Invertebrates were sampled using a 500mm mesh D-framed hand-net, and fish with hand-nets, by direct observation and non-lethal trapping. Aquatic surveys were conducted in the wet season (July and September 2003). Freshwater community surveys were focussed on the relatively unpolluted streams 1 & 3, and Pui O Marsh & Taro Bed.
6.3.8 Surveys of intertidal habitats including mangrove and sandy shore habitats in the Assessment Areas were undertaken. Vegetation surveys were conducted on mangrove stands. Species present and the abundance of species were recorded by direct observation at low tide. Surveys were conducted in the wet season (July and September 2003).
6.3.9 Potential ecological impacts arising from the Project were assessed following EIAO-TM Annex 16 guidelines and the impacts evaluated based on criteria in EIAO-TM Annex 8.
6.4.1 The location of recognised areas of conservation interest within the Assessment Area is shown in Figure 6.2 a to Figure 6.2c.
6.4.2
Under the South Lantau Coast Outline
Zoning Plan (OZP No. S/SLC/123), much of the Pui O Assessment Area is
zoned as Coastal Protection Area. The CPA covers a long strip of land between
the coastline and South Lantau Road from Pui O to Shui Hau thereby encompassing
the low-lying Pui O marsh areas. The proposed raw water mains alignment between
South Lantau Road and the existing water tunnel at the western end of the Pui O
Assessment Area would be located on land zoned CPA.
6.4.3 According to the South Lantau Coast OZP, the intention of the Coastal Protection Zone is to protect the natural character of the shore-line, to safeguard the beaches and their immediate hinterland, and to prevent ribbon development in a haphazard manner along the South Lantau coast.
6.4.4 The boundary of the Lantau South Country Park follows hillsides adjacent to Pui O below Sunset Peak and the Chi Ma Wan peninsular and is in close proximity to South Lantau Road at the eastern part of the Pui O assessment area (see Figure 6.2a to 6.2c). None of the proposed works area would be located inside Country Park. Designated in 1978, the Lantau South Country Park is the largest in Hong Kong and comprises a total area of 5640 ha including a variety of land habitats ranging from grassland to woodland areas. Within the Pui O assessment area the Lantau South Country Park mainly comprised tall shrubland, woodland and areas of grassland habitats.
6.4.5 The Pui O marsh has long been recognised by academics and local conservation groups (e.g. Green Lantau Association) as being an area of conservation interest. The marsh’s special conservation value was recently confirmed during the territory-wide Biodiversity Survey conducted by researchers from HKU’s Department of Ecology & Biodiversity, who found that the site was a ‘hotspot’ of biological diversity.
Habitat Type and
Vegetation
6.4.6 Recent field surveys identified thirteen habitat types within the Assessment Area: secondary woodland, tall shrubland, grassland/shrubland mosaic, plantation, village/developed area, wasteland/abandoned area, active agricultural land, abandoned agricultural land, stream/pond, backshore vegetation, mangrove/mudflat, sandy shore and rocky shore.
6.4.7 Representative photographs of habitats are given in Appendix 6.1. Photographs of species of conservation interest are given in Appendix 6.2. Plant species recorded in the Assessment Area are listed in Appendix 6.3. A more detailed description of habitats recorded in the Assessment Area is given in the following sections.
6.4.8 Woodland habitat was extensive across the Assessment Area, forming a continuous expanse covering the lower hillslopes surrounding the Pui O area. The majority of woodland habitat was secondary in nature, with tree growth in some areas exceeding 10m. Plant diversity was moderate/high, with several native tree species (e.g., Aporusa dioca, Sterculia lanceolata, Mallotus paniculatus, Tetradium glabrifolum) commonly recorded. In addition ‘fung shui’ woodland was identified at the bottom of the hillslopes close to the Ham Tin and Pui O Lo Wai Tsuen and Pui O San Wai Tsuen. Owing to the continuous woodland cover, the habitat provided by ‘fung shui’ areas of woodland were not differentiated as a separate habitat from the secondary woodland.
6.4.9 Two species of conservation interest were recorded from woodland habitat in the Assessment Area, the protected shrub Pavetta hongkongensis, and the IUCN listed tree Aquilaria sinensis. Both these species were relatively common in woodland habitats throughout the Assessment Area, and were present inside and adjacent to the proposed works area at both ends of the proposed raw water mains alignment.
6.4.10 Pavetta hongkongensis is common in woodland habitats throughout Hong Kong, but is protected under local legislation. Although common in Hong Kong, A.sinensis is endemic to China, where it is threatened by habitat loss. It is a Category III protected species under Chinese Legislation, and is listed as Vulnerable in the IUCN Red List of Threatened Species (IUCN, 2003).
6.4.11 Much of the low-lying area between the Pui O coast and South Lantau Road consists of abandoned agricultural land derived from past cultivation of rice and taro. This habitat forms a patchwork of permanent and seasonal marshland close to the coast. Areas of taro bed (Colocasia esculenta) to the northwest of Ham Tin village are permanently flooded.
6.4.12 Vegetation in this habitat was dominated by wetland species including aquatic herbs Eichhornia crassipes, Colocasia esculenta, Ammannia baccifera and Cypcreus polystachyos. These wetland plants were subject to grazing by the resident population of Water Buffalo (Bubulis bubulis), which kept much of the plant growth to an open turf-like cover over most areas. Other common plants in this habitat included isolated patches of trees (e.g., Sapium sebiferum), shrubs (e.g., Lantana camara) and herbs (e.g., Mimosa pudica), recorded along path sides, raised bunds, and other drier areas.
6.4.13 The upper slopes of hillsides in the Assessment Area were dominated by tall shrubland habitat, which was continuous with woodland habitats at lower altitudes. Plant species typically recorded from tall shrubland habitat included common and widespread trees (e.g., Cratoxylum lligustrinum, Phyllanthus emblica), shrubs (e.g., Litsea rotundifolia, Rhodomytrus tomentosa) and herbs (e.g., Dicranopteris linearis, Hedyotis acutangula), along with occasional stands of planted exotic species (e.g., Acacia auriculifrormis). No plant species of conservation interest were recorded from this habitat during surveys.
6.4.14 Vegetation on hill summits and other exposed areas within the Assessment Area tended to be sparse, and dominated by low-growing shrubs, herbs and grasses. Species recorded from this habitat were similar to those growing in adjacent areas of tall shrubland. No species of conservation interest were recorded from this habitat type.
6.4.15 Three permanent streams were recorded in the Assessment Area that would fall partially within the proposed works area (labelled as Streams 1-3 on Figures 6.2a to 6.2c).
6.4.16 The largest stream (Stream 1) was located in the north and east of the Assessment Area, and drained the southern slopes of Yi Tung Shan. The stream course was largely natural to the north of South Lantau Road, with good water quality and a substrate consisting of cobbles and large boulders. Riparian vegetation was dense and consisted of common stream-side species such as Cleistocalyx operculata and Pandanus tectorius. Below the South Lantau Road, the stream widened and flowed through disturbed habitat types including active agricultural, developed areas and plantation. In these lower reaches the stream channel was modified with rock-filled gabion and concrete. The lower reaches of the stream were tidally inundated to form an estuary (see Section 6.4.24)
6.4.17 Stream 2 flowed through the centre of Pui O village, and formed a tributary of the larger Stream 1. Though relatively natural in its upper reaches to the north of South Lantau Road, this stream was affected by domestic inputs from village housing within Pui O village. South of the road, the stream was obviously polluted with organic wastes, being malodorous and supporting growths of sewage fungus.
6.4.18 Stream 3 was a relatively small watercourse located at the western end of the proposed works area. The stream appeared to have good water quality, and flowed through a variety of habitat types, including woodland and plantation, before entering and dissipating in abandoned agricultural land to the south of South Lantau Road.
6.4.19 Plantation habitat consisting of exotic and native tree species (e.g., Acasia confusa, Casuarina equisetifolia, Pinus massoniana, Tristania conferta) was recorded in several locations throughout the Assessment Area. The most substantial plantation consisted of large scale planting to the North of the Assessment Area, close to the AFCD Management Centre at Nam Shan. No plant species of conservation interest were recorded from this habitat type.
6.4.20 Several patches of actively managed farmland were recorded in the Assessment Area, including an extensive area beneath the hillsides to the east of Pui O village. Typical crop species recorded from this habitat type included Musa paradisiaca, Carica papaya, Citrus grandis, Saccharum officinarum and Annona squamosa. No plant species of conservation interest were recorded from this habitat type.
6.4.21 Vegetation in developed areas (e.g., roads, water treatment facilities and other buildings) and villages was generally limited to planted ornamental and fruiting species including Acacia confusa, Bombaxmalabaricum, Euphoria longan, Clausena lansium, Macaranga tanarius, Ficus spp. and Bambusa spp. No plant species of conservation interest were recorded from this habitat type.
6.4.22 Wasteland/ abandoned areas were primarily located to the south of Pui O village and in areas adjacent to Ham Tin. This habitat appears to have been formed mainly through filling/dumping on areas of abandoned agricultural land. Vegetation recorded from wasteland/abandoned areas included species typical of disturbed habitats, including Mikania micrantha, Xanthium sibiricum, Solanum torvum, Urena lobata and Triumfetta bartramia. No plant species of conservation interest were recorded from this habitat type.
6.4.23 A narrow strip of backshore vegetation was recorded between Pui O Beach and abandoned agricultural habitats to the north. Species recorded included common and widespread tree (e.g., Pandanus tectorius) and shrub (e.g., Vitex rotundifolia) species. No plant species of conservation interest were recorded from this habitat type.
6.4.24 Occasional mangrove plants were found at the edges of the estuary area inside the southeast boundary of the Assessment Area. Species included the true mangroves, Kandelia candel and Acanthus ilicifolius and associates, Hibiscus tilaceus, Thespesia populnea, Clerodendrum inerme as well as Caesalpinia crista. Raised areas on the mudflat within the estuary supported beds of salt meadow grass formed by Zoysia sinica.
6.4.25 Sandy shore habitat skirts Pui O Bay and is extensively utlised as a gazetted recreational swimming beach. This habitat is moderately exposed to wave action and is formed by mobile sandy substratum with no vegetation cover on the mid shore to low shore. At the high shore vegetation is contiguous with backshore vegetation.
6.4.26 Rocky shore habitat was identified in the southwest corner of the assessment area fringing Pui O Bay. The rocky shore comprised moderate to large rocky boulders with medium wave exposure.
Fauna
6.4.27 Fauna recorded in the Assessment Area during recent surveys is listed in Appendix 6.4.
6.4.28 A total of 31 macroinvertebrate taxa were recorded during recent surveys. The upper courses of Streams 1 & 3 supported similar communities typical of relatively unimpacted lotic habitats, including mayfly nymphs (e.g., Libebiulla sp., Caenis sp.), freshwater shrimps (e.g., Caridina sp.) and trichopteran larvae (e.g., Cheumatopsyche sp., Hydropsyche sp.). Commonly recorded invertebrates at Pui O Marsh & Taro Bed included aquatic hemiptera (e.g., Diplyonchus rusticum, Corixidae, Notonectidae), beetle larvae and adults (e.g., Helochares sp.) and several species of odonate nymphs.
6.4.29 A total of 10 fish species were recorded from streams and other freshwater habitats in the Assessment Area. All but one of these species (Chinese Moon Snakehead, Channa asiatica) are common and widespread in Hong Kong. The Chinese Moon Snakehead was observed in a small pool close to abandoned agricultural land to the north of Ham Tin village. This species is considered of conservation interest by Fellowes et al. (2002) due to a restricted local distribution and declining local, regional and global populations.
6.4.30 Two mammal species were recorded from the Assessment Area during recent surveys. A suspected squirrel sighting was made from woodland habitat towards the west of the proposed works area. Additionally, several Japanese Pipistrelle (Pipistrellus abramus) were observed hawking insects at dusk close to Pui O Village. Although both of these species are listed under the Wild Animals Protection Ordinance (Cap 170, Sch. 2), neither are considered of particular conservation interest. Japanese Pipistrelle are common and widespread in Hong Kong, and can utilise a wide range of habitats, including highly disturbed areas.
6.4.31 A total of four amphibian and three reptile species were observed in the Assessment Area during recent surveys. One of the recorded species, the Common Rat Snake (Ptyas mucosus), is considered of conservation interest. Regional populations of the Common Rat Snake are thought to be in drastic decline, and the large, secure population in Hong Kong is therefore considered of potential regional conservation concern (Fellowes et al. 2002). A single juvenile Common Rat Snake was recorded from plantation habitat in the north of the Assessment Area, adjacent to the South Lantau Road.
6.4.32 Twenty-two butterfly and 15 odonate species were recorded from the Assessment Area during recent surveys. All recorded species are common and widespread in Hong Kong.
6.4.33 Fifty-nine species of avifauna were recorded from the Assessment Area during recent surveys and ad-hoc observations made during the 2003/2004 dry season. The composition of avifaunal communities reflected the mix of habitat types in the Assessment Area, and included species typical of disturbed habitats (e.g., Black-necked Starling, Sturnus nigricollis; Tree Sparrow, Passer montanus), in addition to species with more specialised habitat requirements (e.g., largely woodland-dependent species such as Forest Wagtail, Dendronanthus indicus and Crested Goshawk, Accipiter trivirgatus). Of particular interest were avifauna communities recorded from abandoned agricultural land and intertidal habitats. Six species of conservation interest (Chinese Pond Heron, Areola bacchus; Little Egret, Egretta garzetta; Great Egret, Egretta alba; Grey Heron, Ardea cinerea; Slaty-breasted Rail, Rallus striatus; and Red-billed Starling, Sturnus sericeus) were recorded from these habitat types, and are described in the following sections.
6.4.34
Four ardeid species of conservation
interest (Chinese Pond Heron, Ardeola
bacchus; Great Egret, Casmerodius
alba; Grey Heron, Ardea cinerea;
Little Egret, Egretta garzetta) were
recorded from abandoned agricultural land and intertidal habitats in the
Assessment Area. The large, fairly secure populations of Great Egret, Little
Egret and Grey Heron that occur in Hong Kong are considered important in a
regional context (Fellowes et al.,
2002). Chinese Pond Heron are considered of conservation importance due to
locally declining populations. Despite the reduced numbers of this species in
Hong Kong, the local population is still large enough to be of regional
significance (Carey et al., 2001).
6.4.35
A single
Slaty-breasted Rail (Rallus striatus) was recorded from
abandoned agricultural land within the Assessment Area. The species is a
locally distributed resident in Hong Kong, with most records coming from
mangroves and brackish waters in the Deep Bay Area (Carey et al., 2001). Fellowes et al.
(2002) consider the Rail of regional conservation concern due to a potentially
limited and declining regional population.
6.4.36 Red-billed Starling (Sturnus sericeus) is a common winter visitor to a variety of lowland habitats in Hong Kong. The species is considered of global conservation concern by Fellowes et al. (2002), and is listed as Near Threatened in the IUCN Red Data Lists (IUCN, 2002). A flock of approximately 20 birds was observed from abandoned agricultural land within the Assessment Area during the 2003/2004 dry season.
6.4.37 Commonly recorded species in the mangrove/mudflat habitat at the head of the Pui O estuary area were crabs (Perisesarma bidens, Metagrapsus frontalis, Sesarmops sinensis, Uca arcuata, Scylla cf. paramamosain), mud snails (Cerithidea spp.) and the neritid snails (Clithon spp.).
6.4.38 Sandy shore habitat supported ghost crabs (Ocypodes ceratophthalmus, Ocypodes gaimardi) with frequent burrows at the high shore. Sand-bubbler crabs (Scopimera globosa) were also occasionally recorded. Hermit crabs (Clibanarium sp.) were infrequently recorded usually inhabiting Turitella shells. Surf clams (Donax sp.) were occasionally recorded on the low shore.
6.4.39 At the backshore, the common sesarmine crab Perisesarma bidens were commonly recorded particularly in a small pool area behind the western end of Pui O beach. In addition, this semi-terrestrial species were occasionally recorded inhabiting a wet seep on the adjacent lower slopes of tall shrubland area.
6.4.40 Rocky shore habitat supported typical and widespread species of moderately exposed rocky comprising rock oysters (Saccostrea cullculata), barnacles (Tetraclita sp., Capitella mitella) sea slaters (Ligia exotica), small shore crabs (Hemigrapsus sanguineus), limpets (Notoacmaema schrenkii) and snails (Monodonta labio, Nerita albicilla and Morula musiva).
6.5.1 In accordance with the EIAO-TM Annex 8 criteria, the ecological importance of recorded habitats has been evaluated in Tables 6.1a - 6.1e below.
Table 6.1a Ecological Value of Woodland and Abandoned Agricultural Land Habitat
|
Criteria |
Woodland |
Abandoned
Agricultural Land |
|
Naturalness |
Habitats
relatively undisturbed. |
The
habitat is formed from abandoned rice and taro fields, and is maintained by
Water Buffalo (Bubulis bubulis)
grazing. |
|
Size |
Woodland
habitat was extensive in the Assessment Area. |
The
habitat is moderate in size. |
|
Diversity |
Moderate-high. |
Moderate. |
|
Rarity |
Two
plant species of conservation interest, the shrub Pavetta hongkongensis and the tree Aquilaria sinensis recorded from this habitat type. |
Five
bird species of conservation interest (Chinese Pond Heron, Areola bacchus; Little Egret, Egretta garzetta; Great Egret, Egretta alba; Slaty-breasted Rail, Rallus striatus; and Red-billed
Starling, Sturnus sericeus)
recorded from this habitat type. One
fish species of conservation interest (Chinese Moon Snakehead, Channa asiatica) recorded from the
habitat. Freshwater
wetlands
are relatively rare habitats in Hong Kong. |
|
Recreatability |
Moderate. |
The
habitat could be re-created on suitable areas of low-lying land. |
|
Fragmentation |
The
habitat is not fragmented. |
The
habitat is not fragmented. |
|
Ecological linkage |
The
habitat falls partially within Lantau South Country Park and areas zoned as
CPA. |
The
habitat falls within an area zoned as CPA. |
|
Potential value |
Low-moderate. |
Moderate. |
|
Nursery ground |
No
significant records. |
Various
invertebrate larvae and tadpoles were recorded from the habitat. |
|
Age |
Woodland
is estimated to be over 40 years old. |
Unknown. |
|
Abundance/
Richness of Wildlife |
Moderate. |
Moderate-high. |
|
Ecological
value |
Moderate-High. |
High. |
Table 6.1b Ecological Value of Tall Shrubland Grassland/Shrubland Mixture Habitat
|
Criteria |
Tall
Shrubland |
Grassland/Shrubland
Mixture |
|
Naturalness |
The
habitat is largely natural, although is probably maintained by hill fires. |
The
habitat is largely natural, although is probably maintained by hill fires. |
|
Size |
Moderate. |
Small. |
|
Diversity |
Low-moderate. |
Low. |
|
Rarity |
No
species of conservation interest recorded from this habitat type. |
No
species of conservation interest recorded from this habitat type. |
|
Recreatability |
Moderate-high. |
Moderate-high. |
|
Fragmentation |
The
habitat is not fragmented. |
The
habitat is largely confined to hill tops and other exposed locations. |
|
Ecological linkage |
The
habitat falls within Lantau South Country Park. |
The
habitat falls within Lantau South Country Park. |
|
Potential value |
Moderate. |
Moderate. |
|
Nursery ground |
No
significant records. |
No
significant records. |
|
Age |
Approximately
15-20 years. |
Approximately
10-15 years. |
|
Abundance/
Richness of Wildlife |
Low-moderate. |
Low. |
|
Ecological
value |
Low-moderate |
Low |
Table 6.1c Ecological Value of Streams and Plantation Habitat
|
Criteria |
Streams |
Plantation |
|
Naturalness |
The
upper courses of all streams remain largely natural, the lower courses have
been variously modified through pollution and channel regulation. Stream 2
especially was impacted by moderate-high levels of organic pollution. |
The
habitat is dominated by mostly exotic planted trees. |
|
Size |
Stream
1: Large Stream
2: Moderate Stream
3: Small |
Small-moderate. |
|
Diversity |
Low-moderate. |
Low. |
|
Rarity |
No
species of conservation interest recorded from this habitat type. |
One
reptile of conservation interest (Common Rat Snake, Ptyas mucosus), recorded from this
habitat type. |
|
Recreatability |
Recreatability
is low-moderate. |
Recreatability
is high. |
|
Fragmentation |
The
streams are not fragmented. |
Small
areas of plantation habitat found throughout the Assessment Area. |
|
Ecological linkage |
The
streams fall partially within Lantau South Country Park and areas zoned as
CPA. |
The
habitat falls partially within Lantau South Country Park and areas zoned as
CPA. |
|
Potential value |
Low-moderate. |
Moderate. |
|
Nursery ground |
No
notable records. |
Juvenile
Common Rat Snake (Ptyas mucosus)
recorded from this habitat type. |
|
Age |
N/a. |
Approximately
30-40 years. |
|
Abundance/
Richness of Wildlife |
Stream
1: Moderate. Stream
2: Low Stream
3: Low-moderate. |
Low-moderate. |
|
Ecological
value |
Stream 1: Moderate Stream 2: Low Stream 3:
Low-moderate |
Low-moderate. |
Table 6.1d Ecological Value of Active Agricultural Land, Village/Developed Area, Wasteland/Abandoned Area and Backshore Vegetation Habitat
|
Criteria |
Active Agricultural
Land, Village/Developed Area, Wasteland/Abandoned Area |
Backshore
Vegetation |
|
Naturalness |
Habitats
are man-made. |
Habitats
are largely natural. |
|
Size |
Moderate. |
Habitat
limited to a thin strip between Pui O beach and abandoned agricultural land. |
|
Diversity |
Low. |
Low. |
|
Rarity |
No
species of conservation interest recorded from these habitats. |
No
species of conservation interest recorded from these habitats. |
|
Recreatability |
High. |
Low. |
|
Fragmentation |
Patches
of disturbed habitats found throughout the Assessment Area. |
The
habitat is not fragmented. |
|
Ecological linkage |
The
habitats fall partially within an area zoned CPA. |
The
habitats fall within an area zoned CPA. |
|
Potential value |
Low-moderate. |
Low-moderate. |
|
Nursery ground |
No
notable records. |
No
notable records. |
|
Age |
N/a. |
Approximately
20-30 years. |
|
Abundance/
Richness of Wildlife |
Low. |
Low. |
|
Ecological
value |
Very Low |
Low |
Table 6.1e Ecological Value of Mangrove/Mudflat and Sandy/Rocky Shore Habitat
|
Criteria |
Mangrove/Mudflat |
Sandy/Rocky
Shore |
|
Naturalness |
The
habitat is largely natural, although affected by minor organic pollution and
river channel modification. |
Habitat
are largely natural, although sandy shore at Pui O is extensively utilised
for recreation. |
|
Size |
Small. |
Small. |
|
Diversity |
Moderate. |
Low. |
|
Rarity |
Four
avifaunal species of conservation interest (Chinese Pond Heron, Areola bacchus; Little Egret, Egretta garzetta; Great Egret, Egretta alba; Grey Heron, Ardea cinerea) recorded from this
habitat type. |
Two
avifaunal species of conservation interest (Little Egret, Egretta garzetta; Great Egret, Egretta alba) recorded from this
habitat type. |
|
Recreatability |
Low. |
Low. |
|
Fragmentation |
The
habitat is not fragmented. |
The
habitat is not fragmented. |
|
Ecological linkage |
The
habitat falls within an area zoned CPA. |
The
habitat falls partially within an area zoned CPA. |
|
Potential value |
Low-moderate. |
Low-moderate. |
|
Nursery ground |
No
notable records, although mangrove and estuarine habitats are thought to
provide breeding and nursery grounds for some fish species. |
No
notable records. |
|
Age |
N/a. |
N/a. |
|
Abundance/
Richness of Wildlife |
Moderate. |
Low-moderate. |
|
Ecological
value |
Moderate-high |
Low-moderate |
6.5.2 Woodland habitats within the Assessment Area were found to be relatively diverse, extensive and unfragmented, and to support moderate-high diversity of plant species (including some species of conservation interest). Woodland habitats were considered of moderate-high ecological value.
6.5.3 Abandoned agricultural land in the Assessment Area was found to form an extensive area of freshwater wetland; a relatively rare habitat type in Hong Kong. The habitat also supported several avifaunal and one fish species of conservation interest. Abandoned agricultural land was considered of high ecological value.
6.5.4 Tall Shrubland and grassland/shrubland mixture in the Assessment Area were found to support a low to low-moderate diversity of flora and fauna. No species of conservation interest were recorded from these habitat types. The ecological value of tall shrubland and grassland/shrubland mixture was considered low-moderate and low respectively.
6.5.5 The ecological value of stream habitats considered in the Assessment was found to be variable. Stream 1 was relatively large, unmodified along much of its course, and was considered of moderate ecological value. Stream 3, although largely unmodified, was very small in size, and was therefore considered of low-moderate ecological value. Stream 2 was heavily polluted with organic wastes below the South Lantau Road, and was considered of low ecological value.
6.5.6 Plantation habitats within the Assessment Area were relatively mature, but were dominated by exotic species, and were found to support only one species of conservation interest. This habitat type was considered of low-moderate ecological value.
6.5.7 Active agricultural land, village/developed areas and wasteland/abandoned areas were found to be of very low ecological value, being highly disturbed and modified habitats that supported no species of conservation interest.
6.5.8 Backshore vegetation was considered to be of low ecological value, being small in size and supporting no species of conservation interest.
6.5.9 Mudflat/mangrove habitats in the Assessment Area were relatively natural, and supported a number of avifaunal species of conservation interest. The habitat was rated as moderate-high ecological value.
6.5.10 Sandy/rocky shores within the Assessment Area were subject to disturbance from human activities, and supported few species of conservation interest. These habitats were considered of low-moderate ecological value.
6.5.11 With reference to EIAO-TM Annex 8 criteria, species of conservation interest recorded in the Assessment Areas are evaluated in Table 6.2 below.
Table 6.2 Species of Conservation Interest Recorded in the Assessment Area
|
Common Name |
Scientific Name |
Status* |
Protection Status,
Distribution, Rarity and Other Notes** |
|
Flora |
|
|
|
|
Hong
Kong Pavetta |
Pavetta
hongkongensis |
- |
Common
in Hong Kong. Protected under Hong Kong Law. |
|
Incense
Tree |
Aquilaria sinensis |
- |
Common
in Hong Kong. Listed as vulnerable in IUCN Red Data List. |
|
|
|
|
|
|
Fauna |
|
|
|
|
Fish |
|
|
|
|
Chinese
Moon Snakehead |
Channa asiatica |
LC |
Restricted
local distribution. Local, regional and global population in decline. |
|
|
|
|
|
|
Avifauna |
|
|
|
|
Chinese
Pond Heron |
Ardeola bacchus |
PRC |
Large
local population is declining. |
|
Great
Egret |
Casmerodius alba |
PRC |
Large,
secure population of regional significance. |
|
Grey
Heron |
Ardea cinerea |
PRC |
Large,
secure population of regional significance. |
|
Little
Egret |
Egretta garzetta |
PRC |
Large,
secure population of regional significance. |
|
Slaty-breasted
Rail |
Rallus
striatus |
RC |
Potentially
restricted and declining regional population |
|
Red-billed
Starling |
Sturnus sericeus |
GC |
Regionally important population in Hong Kong. |
|
|
|
|
|
|
Herpetofauna |
|
|
|
|
Common
Rat Snake |
Ptyas mucosus |
PRC |
Regionally
declining population. |
|
|
|
|
|
*LC – Local Concern (Habitat loss/damage
in Hong Kong would pose significant threat to local survival); PRC – Potential
Regional Concern (Large, secure populations in Hong Kong are of regional
significance); RC – Regional Concern (Habitat loss in Hong Kong would have
implications for the survival of the species in South China); GC – Global
Concern (Further habitat loss or damage in Hong Kong may have implications for
the global survival of the species). Refer to Fellowes et al. (2002) for further explanation of status.
**Information
taken from various sources including Corlett et al. (2000), Carey et al.
(2001) and Fellowes et al. (2002).
6.6.1 Several potential ecological impacts resulting from construction phase activities have been identified, and are outlined in the following sections.
6.6.2 During the construction phase, potential impacts due to the proposed Project may include:
·
Direct
loss of woodland habitat due to vegetation clearance;
·
Indirect
general disturbance to wildlife (particularly avifauna) in woodland and
abandoned agricultural land habitats;
·
Indirect
impact to stream courses due to construction site run-off.
6.6.3 Laying of raw water mains pipes at Pui O would involve excavation of a 2.5m wide trench to accommodate the 1.2m diameter water pipes. These works would be accommodated within a works area 10m wide. The proposed alignment would pass through woodland and developed/ village area habitats. Reprovisioning and uprating works on pumping stations at Pui O would take place inside the existing site boundaries. The approximate areas of potentially directly affected habitats are summarised in Table 6.3 below. Owing to trench excavation, clearance of vegetation would be unavoidable along the raw water mains alignment. However, within the remaining 10m wide temporary works area, vegetation would only be cleared if necessary. Although some areas of the alignment corridor would be used for temporary location, access and storage of pipe materials, plant equipment and excavated materials, the 10m wide corridor is primarily for the purpose to allow minor adjustments of the raw water mains alignment subject to site conditions at the design and construction stages, if necessary.
Table 6.3 Habitats directly affected by the laying of raw water mains at Pui O
|
Habitat Type |
Trench excavation |
Temporary Works area |
|
Village/Developed
Area |
0.25 ha |
1 ha |
|
Woodland |
0.1 ha |
0.4 ha |
6.6.4 Habitats and associated fauna adjacent to the works area may be subject to indirect impacts resulting from increased human activities/disturbance such as noise-generating construction plant equipment. Potential disturbance to avifauna in woodland and abandoned agricultural land habitats may be of concern. Noisy construction phase activities and general increases in human activity could disturb wildlife utilising habitats close to the works areas. Potential disturbance effects may include the avoidance of areas adjacent to the works area, and reductions in wildlife density close to the source of disturbance.
6.6.5 Laying of raw water mains would also cross three streams (described in Section 6.4.15 to 6.4.18 of this report). Run-off and disturbance from works may give rise to indirect impacts to aquatic communities downstream of the works area due to increased sedimentation. Increased sedimentation can 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 fish and invertebrates. Increases in turbidity caused by high sediment levels can inhibit photosynthesis by aquatic plants, and impede feeding and other activities in animals that are largely dependant on sight (e.g., some fish species).
6.6.6 Aquatic communities may potentially also be indirectly impacted through spillage of oils and other pollutants from the works area during the construction phase. Potential spillage of oils/chemicals could lead to direct lethal/non-lethal effects on aquatic organisms.
6.6.7 Indirect disturbance to habitats may also arise from storage or dumping of construction material.
6.6.8 No substantial ecological impacts are anticipated to arise during the operation phase of the Project.
6.7.1 Potential ecological impacts resulting from construction/operation phase activities have been evaluated according to Table 1 of Annex 8 of the EIAO-TM, and are summarised in Tables 6.4a-e below.
Table 6.4a Overall Impact Evaluation of Woodland and Abandoned Agricultural Land Habitat
|
Evaluation Criteria |
Woodland |
Abandoned Agricultural Land |
|
Habitat
quality |
The habitat
quality is moderate-high. |
The habitat
quality is high. |
|
Species |
Potential
direct and indirect impact to two plant species of conservation interest (Pavetta hongkongensis and Aquilaria sinensis). |
No
direct impact to species of conservation interest. Potential
indirect impact to five bird species of conservation interest (Chinese Pond
Heron, Areola bacchus; Little
Egret, Egretta garzetta; Great
Egret, Egretta alba; Slaty-breasted
Rail, Rallus striatus; and
Red-billed Starling, Sturnus sericeus)
recorded from this habitat type. No
direct/indirect impact anticipated to fish species of conservation interest
(Chinese Moon Snakehead, Channa
asiatica) recorded from the habitat. |
|
Size/Abundance |
Direct
impact to 0.1ha of habitat due to trench excavation, and disturbance to a
further 0.4ha of habitat falling within temporary works areas. |
No
direct loss of habitat. |
|
Duration |
Habitat
loss would be limited to the construction phase and a period of
re-establishment following landscaping works. Indirect
impacts such as noise disturbance would be limited to the construction phase. |
Indirect
impacts such as noise disturbance would be limited to the construction phase. |
|
Reversibility |
Loss
of habitat would be reversible. Indirect
disturbance impacts would be temporary and reversible. |
Indirect
disturbance impacts would be temporary and reversible. |
|
Magnitude |
The
scale of the impact is considered low. |
The
scale of the impact is considered low. |
|
Overall impact
conclusion |
Low-Moderate |
Low |
Table 6.4b Overall Impact Evaluation of Tall Shrubland Grassland/Shrubland Mixture Habitat
|
Evaluation Criteria |
Tall Shrubland |
Grassland/Shrubland Mixture |
|
Habitat
quality |
The habitat
quality is low-moderate. |
The habitat
quality is low. |
|
Species |
No
impact to species of conservation interest, although there may be potential
minor indirect impact to wildlife. |
No
ecological impact anticipated. |
|
Size/Abundance |
No
direct loss of habitat. |
No
ecological impact anticipated. |
|
Duration |
Indirect
impacts such as noise disturbance would be limited to the construction phase. |
No
ecological impact anticipated. |
|
Reversibility |
Indirect
disturbance impacts would be temporary and reversible. |
No
ecological impact anticipated. |
|
Magnitude |
The
scale of the impact is considered very-low. |
No
ecological impact anticipated. |
|
Overall impact
conclusion |
Very Low |
No Impact |
Table 6.4c Overall Impact Evaluation of Streams and Plantation Habitat
|
Evaluation Criteria |
Streams |
Plantation |
|
Habitat
quality |
Stream
1: Moderate Stream
2: Low Stream 3:
Low-moderate |
The habitat
quality is low-moderate. |
|
Species |
No
direct impact to species of conservation interest, although there may be
potential indirect impact to the wildlife. |
No
direct impact to species of conservation interest, although there may be
potential indirect impact to the wildlife, including one reptile of
conservation interest (Common Rat Snake, Ptyas
mucosus). |
|
Size/Abundance |
No
direct loss of habitat. |
No
direct loss of habitat. |
|
Duration |
Potential
indirect impacts such as noise disturbance and increased sedimentation would
be limited to the construction phase. |
Potential
indirect impacts such as noise disturbance would be limited to the
construction phase. |
|
Reversibility |
Indirect
disturbance impacts would be temporary and reversible. |
Indirect
disturbance impacts would be temporary and reversible. |
|
Magnitude |
The
scale of the impact is considered low. |
The
scale of the impact is considered very low. |
|
Overall impact
conclusion |
Very Low |
Very Low |
Table 6.4d Overall Impact Evaluation of Active Agricultural Land, Village/Developed Area, Wasteland/Abandoned Area and Backshore Vegetation Habitat
|
Evaluation Criteria |
Active Agricultural
Land, Village/Developed Area, Wasteland/Abandoned Area |
Backshore Vegetation |
|
Habitat
quality |
The habitat
quality is very low. |
The habitat
quality is low. |
|
Species |
No
direct impact to species of conservation interest, although there may be
potential indirect impact to the wildlife. |
No
direct impact to species of conservation interest, although there may be
potential indirect impact to the wildlife. |
|
Size/Abundance |
Direct
impact to 0.25ha of habitat due to trench excavation, and disturbance to a
further 1ha of habitat falling within temporary works areas. |
No
direct loss of habitat. |
|
Duration |
Habitat
loss would be limited to the construction phase. Indirect
impacts such as noise disturbance would be limited to the construction phase. |
Indirect
impacts such as noise disturbance would be limited to the construction phase. |
|
Reversibility |
Loss
of habitat would be reversible. Indirect
disturbance impacts would be temporary and reversible. |
Indirect
disturbance impacts would be temporary and reversible. |
|
Magnitude |
The
scale of the impact is considered very low. |
The
scale of the impact is considered very-low. |
|
Overall impact
conclusion |
Very Low |
Very Low |
Table 6.4e Overall Impact Evaluation of Mangrove/Mudflat and Sandy/Rocky Shore Habitat
|
Evaluation Criteria |
Mangrove/Mudflat |
Sandy/Rocky Shore |
|
Habitat
quality |
The habitat
quality is moderate-high. |
The habitat
quality is low-moderate. |
|
Species |
No
direct impact to species of conservation interest. |
No
direct impact to species of conservation interest. |
|
Size/Abundance |
No
ecological impact anticipated. |
No
ecological impact anticipated. |
|
Duration |
No
ecological impact anticipated. |
No
ecological impact anticipated. |
|
Reversibility |
No
ecological impact anticipated. |
No
ecological impact anticipated. |
|
Magnitude |
No
ecological impact anticipated. |
No
ecological impact anticipated. |
|
Overall impact
conclusion |
No
ecological impact anticipated. |
No
ecological impact anticipated. |
|
|
No Impact |
No Impact |
6.7.2 Direct impacts to habitats arising the Project would be largely limited to areas of low ecological value (village/developed areas) since most of proposed raw water mains would be constructed along approximately 1km of existing road (i.e. mainly along South Lantau Road), with no direct impacts on species of conservation interest.
6.7.3 At either ends of the proposed raw water mains alignment, direct impacts to woodland would be an unavoidable consequence of the works. In total, the proposed alignment would pass through approximately 0.1km of woodland habitat at the eastern section of the assessment area and 0.3km of woodland habitat at the western section of the assessment area. During recent field surveys it was found that individuals of the protected shrub Pavetta hongkongensis occurred scattered throughout these woodland habitats, including across areas adjacent to the proposed alignment. In addition the woodland habitats also supported the common, though protected tree, Aquilaria sinensis.
6.7.4 Vegetation clearance along the 2.5m wide trench for the proposed Project would affect approximately 0.1 ha of woodland habitat. In addition direct impacts from work activities may also affect the vegetation within the 10m wide works area amounting to 0.4 ha of woodland habitat. However, vegetation within the 10m wide would only be cleared as necessary. This scale of impact is considered to be low and temporary limited to the construction phase and would be reversible following reinstatement of the works area through landscaping. Therefore, direct impacts to woodland habitat are considered to low-moderate. It was considered loss and/or direct disturbance of Pavetta hongkongensis and Aquilaria sinensis within the works area would be low-moderate.
6.7.5 Raw water mains would be constructed over the top of streams in the assessment area within which no species of conservation interest were identified during recent field surveys. Owing to the construction method, potential water quality impact through release of sediment during construction is expected to be minimal and highly localised. Elevations in sediment levels associated with construction phase works are not expected to have adverse impacts on downstream habitats such as abandoned agricultural land and mangrove/mudflats or other intertidal habitats. Due to the small scale and temporary nature of works and provided that good site practices are observed, it was considered indirect impacts on streams due to construction site run-off would be very low.
6.7.6 Construction phase disturbance to wildlife in habitats adjacent to the works areas would be temporary, and would generally affect very low (i.e. village/developed area, active agricultural land and abandoned/wasteland) or low-moderate value ecological habitats (i.e. plantation) where few species of conservation interest were recorded.
6.7.7 All avifaunal species of conservation interest were recorded from abandoned agricultural land and intertidal habitats that would not be directly affected by the proposed works. Indirect disturbance impacts to these species are expected to be relatively minor. The works would be temporary in nature and small in scale. Furthermore, works would be conducted along the South Lantau Road, an existing source of disturbance, for much of the alignment that disturbance-sensitive species would already avoid. Temporary works within woodland may cause localised disturbance impacts and have low level of impact on wildlife.
6.7.8 Potential impacts to species of conservation interest are described in sections 6.7.1-6.7.7 above, and summarised in Table 6.5 below.
Table 6.5 Overall Impact Evaluation to Species of Conservation Interest
|
Species of
Conservation Interest |
Potential Impact* |
||
|
Common Name |
Scientific Name |
Description |
Evaluation |
|
Flora |
|
|
|
|
Hong
Kong Pavetta |
Pavetta hongkongensis |
Potential
direct impacts to individuals located close to or within proposed works
areas. |
Low-moderate |
|
Incense
Tree |
Aquilaria sinensis |
Potential
direct impacts to individuals located close to or within proposed works
areas. |
Low-moderate |
|
Fauna |
|
|
|
|
Fish |
|
|
|
|
Chinese
Moon Snakehead |
Channa asiatica |
Snakehead recorded
from small pool on the fringe of abandoned agricultural land habitat,
approximately 180m from the proposed raw water main alignment. No impacts to
this species are anticipated. |
No impact |
|
Avifauna |
|
|
|
|
Chinese
Pond Heron |
Ardeola bacchus |
All
avifaunal species of conservation interest were recorded from abandoned
agricultural land and intertidal habitats that would not be directly affected
by the proposed works. Indirect
impacts to these species are expected to be relatively minor. The works would
be temporary in nature and small in scale. Furthermore, works would be
conducted along the South Lantau Road, an existing source of disturbance, for
much of the alignment. |
Low |
|
Great
Egret |
Casmerodius alba |
Low |
|
|
Grey
Heron |
Ardea cinerea |
Low |
|
|
Little
Egret |
Egretta garzetta |
Low |
|
|
Slaty-breasted
Rail |
Rallus striatus |
Low |
|
|
Red-billed
Starling |
Sturnus sericeus |
Low |
|
|
Herpetofauna |
|
|
|
|
Common
Rat Snake |
Ptyas mucosus |
Rat Snakes
are common and widespread in Hong Kong with no specialised habitat
requirements. Snakes potentially disturbed by construction phase activities
would therefore be likely to relocate to nearby areas further from the source
of disturbance. Potential disturbance impacts are therefore considered minor. |
Very Low |
*Refers to
potential construction phase impact only. No operation phase impacts are anticipated.
6.7.9 No significant impacts during the operation phase of the Project have been identified. Operation phase impacts are considered to be negligible.
6.8.1 No concurrent projects have been identified during the construction phase that would give rise to impacts beyond the potential impacts discussed above.
6.9.1 Following EIAO-TM Annex 16 guidelines, mitigation measures are proposed in this section to avoid, minimise and compensate for identified ecological impacts.
6.9.2 Alternative alignment options for the proposed raw water mains have been considered. Direct impacts to habitats over most of the distance between the water tunnel portals have been avoided by confining the proposed alignment to South Lantau Road. In addition, direct disturbance to streams would be avoided since the proposed raw water mains would be elevated to span over the top of streams.
6.9.3 All trees should be preserved as far as possible, especially species of high conservation or amenity value. Recommendations to be provided in the Tree Survey Report to mitigate impacts on trees should be followed. Where trees are to be preserved in-situ, but are likely to be disturbed from works activities, protective fencing/hoarding should be carefully set up around the affected trees.
6.9.4 Disturbance of individuals of the shrub/tree species Pavetta hongkongensis and tree Aquilaria sinensis of conservation interest should be avoided. A buffer to the dripline of each plant of at least 1m radius should be demarcated to prohibit disturbance. Where loss of this species would be unavoidable, it is recommended that these plants may be transplanted to safe locations within the same habitat. Exact receptor sites should be determined by the horticulturist/ecologist on site at the time of the transplantation so that generally plants are moved as short a distance as possible to clear the works area. Specifications for transplantation should be included at the design stage.
6.9.5 Mitigation measure recommended to minimise water quality impact (refer to Chapter 5) would also serve to protect aquatic ecology. Trench excavation works for the raw water mains near the stream courses should be carried out in the dry season, as far as practicable. Site runoff should be directed towards regularly cleaned and maintained silt traps and oil/grease separators to minimise the risk of sedimentation and pollution of river water. The silt and oil/grease separators should be appropriately designed for the local drainage and ground conditions.
6.9.6 Noise mitigation measures through the use of quiet construction plant should be implemented to minimise disturbance to habitats adjacent to the works areas.
6.9.7 Standard good site practice measures should be implemented throughout the construction phase. The measures should include:
·
Placement
of equipment or stockpile in designated works areas and access routes selected
on existing disturbed land to minimise disturbance to natural habitats.
·
Construction
activities should be restricted to works areas that should be clearly
demarcated. The works areas should be reinstated after completion of the works.
·
Waste
skips should be provided to collect general refuse and construction wastes. The
wastes should be disposed of timely and properly off-site.
·
General
drainage arrangements should include sediment and oil traps to collect and
control construction site run-off.
·
Open
burning on works sites is illegal, and should be strictly prohibited. Stove
fires on works sites should also not be allowed. Temporary fire fighting
equipment should be provided particularly in woodland areas.
6.9.8 Planting of trees and other vegetation to reinstate the works area would provide compensation for any unavoidable tree-felling and loss of vegetation resulting from the proposed works. Details will be provided in the tree felling permit with on-site compensatory tree planting conducted on at least a one to one basis. As far as possible compensatory planting should use native plants of the same species that occur in the adjacent woodland habitat and have flowers/fruits attractive to wildlife.
6.10.1 With implementation of the above mitigation measures and following the reestablishment of vegetation in reinstated works areas, it was considered that the Project would have no long-term residual ecological impacts.
6.11.1 The proper implementation of mitigation measures recommended in Section 6.9 should be audited during the construction phase.
6.11.2 Following any transplantation of Pavetta hongkongensis and Aquilaria sinensis individuals, regular monitoring of the trees and seedlings should be conducted to check on the health and condition of the plants. Monitoring should cover the 12-month period following transplantation, monitoring conducted at least twice a month for the first four months after transplantation, and once a month for the remaining eight months. Monitoring should be conducted by a suitably qualified botanist/horticulturalist appointed by the Project Proponent. If audit records indicate that the transplanted plants are not establishing properly, the Landscape Architect should recommend and undertake measures to rescue the plants.
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