6.                  ECOLOGICAL IMPACT

6.1              Introduction

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              Environmental Legislation and Standards

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              Assessment Methodology & Criteria

6.3.1        Existing literature documenting the ecology of Hong Kong and the Pui O area in particular was reviewed. Relevant sources included:

 

Dudgeon, D. and Chan, W. C. E. (1996). Ecological Study of Freshwater Wetland Habitats in Hong Kong. Unpublished report for the Agriculture and Fisheries Department

 

Carey, G.J., Chalmers, M.L., Diskin, D.A., Kennerley, P.R., Leader, P.J., Leven, M.R., Lewthwaite, R.W., Melville, D.S., Turnbull, M., and Young, L. (2001): The Avifauna of Hong Kong. Hong Kong Bird Watching Society, Hong Kong.

 

Lau, M.W.N. & Dudgeon, D. (1999) Composition and distribution of Hong Kong amphibian fauna. Memoirs of Hong Kong Natural History Society 22:1-79.

 

Wilson, K.D.P. (1997) An annotated checklist of the Hong Kong dragonflies with recommendations for their conservation. Memoirs of the Hong Kong Natural History Society 21: 1-68.

 

Tam, N.F.Y & Wong, Y.S. (1997). Ecological Study on Mangrove Stands in Hong Kong. Submitted to AFD.

 

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:

 

Vegetation/habitat Surveys

 

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.

 

Herpetofauna /mammal Surveys

 

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.

 

 

 

 

 

Terrestrial Invertebrates

 

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.

 

Aquatic Communities

 

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.

 

Marine Habitat Surveys

 

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).

 

Impact Assessment

 

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              Baseline Condition

Areas of Conservation Interest

 

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.

 

Coastal Protection Areas (CPA)

 

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.

 

Country Parks (CP)

 

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.

 

Biodiversity Hotspot

 

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.

 

Woodland

 

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).

 

Abandoned agricultural land

 

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.

 

Tall shrubland

 

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.

 

Grassland/shrubland mixture

 

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.

 

Streams

 

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.

 

Plantation

 

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.

 

Active agricultural land

 

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.

 

Village/Developed Area

 

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.

 

Wasteland/Abandoned Area

 

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.

 

Backshore vegetation

 

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.

 

Mangrove/Mudflat

 

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.

 

Sandy shore

 

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.

 

Rocky shore

 

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.

 

Freshwater Communities

 

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.

 

            Mammals

 

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.

 

Herpetofauna

 

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.

 

Terrestrial Invertebrates

 

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.

 

Avifauna

 

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.

 

 

 

            Ardeids

 

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).

 

            Slaty-breasted Rail

 

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.

 
Red-billed Starling
 

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.

 

Intertidal fauna

 

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              Ecological Value

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              Identification of Environmental Impacts

 

6.6.1        Several potential ecological impacts resulting from construction phase activities have been identified, and are outlined in the following sections.

 

Construction Phase

 

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.

 

 

 

Operation Phase

 

6.6.8        No substantial ecological impacts are anticipated to arise during the operation phase of the Project.

 

6.7              Evaluation of Impacts

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

 

 

Construction Phase Impacts

 

Habitat loss

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.

Indirect Impacts on Watercourses

 

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.

 

Indirect disturbance to wildlife

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.

 

Operation Phase Impacts

 

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              Cumulative Impacts

 

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              Mitigation of Adverse Environmental Impacts

 

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.

 

Avoidance

 

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.

 

Minimisation

 

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.

 

Compensation

 

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          Residual Environmental Impacts

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          Environmental Monitoring and Auditing Requirements

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.

 

6.12          References

Agriculture and Fisheries Department (1993) Checklist of Hong Kong Plants: 159p.

Agriculture, Fisheries and Conservation Department (2002) Checklist of Hong Kong Plants 7th Edition 407p.

Bascombe, M.J., Johnston, G. & Bascombe, F.S. (1999) The Butterflies of Hong Kong. Academic Press, London: 422p.

Carey, G.J., Chalmers, M.L., Diskin, D.A., Kennerley, P.R., Leader, P.J., Leven, M.R., Lewthwaite, R.W., Melville, D.S., Turnbull, M., and Young, L. (2001): The Avifauna of Hong Kong. Hong Kong Bird Watching Society, Hong Kong.

Corlett, R., Xing, F., Sai-Chit, N., Chau, L, Wong, L. (2000).  Hong Kong Vascular Plants: Distribution And Status.  Memoirs Of The Hong Kong Natural History Society. Hong Kong.

CLP Power Hong Kong Ltd (2002) 132kV Supply Curcuit from Pui O via Chi Ma Wan Peninsula via Sea Crossing to Cheung Chau EIA Study Final Report.

Dudgeon, D. and Chan, W. C. E. 1996. Ecological Study of Freshwater Wetland Habitats in Hong Kong. Unpublished report for the Agriculture and Fisheries Department

Fellowes, J.R., Lau, M.W.N., Dudgeon, D., Reels, G.T., Ades, G.W.J., Carey, G.J., Chan, B.P.L., Kendrick, R.C., Lee, K.S., Leven, M.R., Wilson, K.D.P. & Yu, Y.T. (2002) Wild animals to watch: Terrestrial and freshwater fauna of conservation concern in Hong Kong. Memoirs of the Hong Kong Natural History Society 25: 123-159.

Morton B. & Morton J. (1983). The Seashore Ecology of Hong Kong. Hong Kong University Press.

IUCN 2003. 2003 IUCN Red List of Threatened Species. <www.redlist.org>

Karsen, S., Lau, M. and Bogadek, A. (1998). Hong Kong Amphibians and Reptiles. 2nd edition. The Provisional Urban Council, Hong Kong.

Lau, M.W.N. & Dudgeon, D. (1999) Composition and distribution of Hong Kong amphibian fauna. Memoirs of Hong Kong Natural History Society 22:1-79.

Pei, K.J.-C.  (2001) The present status of non-flying terrestrial mammals in Hong Kong SAR. In: Wildlife Conservation Foundation (ed.), Workshop on the Status and Conservation of Hong Kong’s Wild Animals and Plants, December 8, 2001 – Proceedings, Wildlife Conservation Foundation, Hong Kong: 130-144.

Reels, G. (1996). Distribution of large mammals in Hong Kong. Porcupine! 15: 36-38

Sun, W. 1997. Aquilaria sinensis. In: IUCN 2003. 2003 IUCN Red List of Threatened Species.

Tam, N.F.Y & Wong, Y.S. (1997). Ecological Study on Mangrove Stands in Hong Kong. Submitted to AFD.

Viney, C, Philipps, K. & Lam, C-Y. (1994). The Birds of Hong Kong and South China. Government Printer, Hong Kong: 244pp.

Yue, P and Chen, Y. comps. 1998. China Red Data Book of Endangered Animals –Pisces. ed. S. Wang. Beijing: Science Press.

Wilson, K.D.P. (1995).  Hong Kong Dragonflies. Hong Kong Urban Council: 211p.

Wilson, K.D.P. (1997) An annotated checklist of the Hong Kong dragonflies with recommendations for their conservation. Memoirs of the Hong Kong Natural History Society 21: 1-68.

                        Wilson, K.D.P., T.W. Tam, B.S.P. Kwan, K.K.Y. Wu, B.S.F. Wong & J.K. Wong (2003).  Field Guide to the Dragonflies of Hong Kong. AFCD. Friends of Country Parks and Cosmos Books Ltd. Hong Kong p381.