8.1.1
This section presents the assessment of potential
ecological impacts resulting from both the upgrading of the Cheung Chau STW and
Pak She SPS and the sewers works of the Project. Literature review and ecological field
surveys were undertaken to establish the ecological baseline for the evaluation
of the ecological importance of habitats and flora/fauna species potentially
affected by the proposed works. The
magnitude of potential ecological impacts arising from the proposed works was
assessed and necessary mitigation is recommended.
8.1.2
This assessment has based on the criteria and guidelines
stated in Annexes 8 and 16 of the EIAO-TM for evaluation and assessment of
terrestrial and marine ecological impacts and has covered the scope outlined in
Section 3.4.6 and Appendix F of the
EIA Study Brief ESB212/2009.
8.2.1
The local relevant regulations, legislation and guidelines for
the protection of species and habitats of ecological importance include the
following:
Ÿ
Technical Memorandum
for the Environmental Impact Assessment Ordinance (Cap 499) (EIAO-TM);
Ÿ
EIAO Guidance Note No.
6/2010;
Ÿ
EIAO Guidance Note No.
7/2010;
Ÿ
EIAO Guidance Note No.
10/2010;
Ÿ
EIAO Guidance Note No.
11/2010;
Ÿ
Hong Kong Planning
Standards and Guidelines Chapter 10 (HKPSG);
Ÿ
Forests and
Countryside Ordinance (Cap 96) and its subsidiary legislation the Forestry
Regulations;
Ÿ
Wild Animals
Protection Ordinance (Cap 170);
Ÿ
Protection of
Endangered Species of Animals and Plants Ordinance (Cap 586);
Ÿ
Country Parks
Ordinance (Cap 208);
Ÿ
Marine Parks Ordinance
(Cap 476);
Ÿ
Town Planning
Ordinance (Cap 131);
Ÿ
PRC Regulations and
Guidelines;
Ÿ
IUCN Red List
Categories and Criteria;
Ÿ
China Red Data Book of
Endangered Species; and
Ÿ
The Convention on
International Trade in Endangered Species of Wild Fauna and Flora (CITES).
8.2.2
Annex 16 of the EIAO-TM sets out the general approach and
methodology for assessments 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 ecological impacts.
8.2.3
EIAO Guidance Note No. 6/2010 clarifies the requirements of
ecological assessments under the EIAO. EIAO Guidance Note No. 7/2010 provides
general guidelines for conducting ecological baseline surveys in order to
fulfil requirements stipulated in the EIAO-TM.
EIAO
Guidance Note No. 10/2010 and EIAO Guidance Note No. 11/2010 outline the methodologies for ecological field surveys on various
terrestrial and marine faunal groups.
8.2.4
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 addresses the issue of
enforcement. The appendices list the legislation and administrative controls
for conservation, other conservation related measures in Hong Kong and
Government departments involved in conservation.
8.2.5
The Forests and Countryside Ordinance (Cap 96) prohibits
felling, cutting, burning or destroying of trees and live plants in forests and
plantations on Government land. Related subsidiary Regulations prohibit the
picking, felling or possession of listed rare 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.
8.2.6
Under the Wild Animals Protection Ordinance (Cap 170),
designated wild animals are protected from being hunted, whilst their nests and
eggs are protected from destruction and removal. All birds and most mammals are
protected under this Ordinance. The Second Schedule of the Ordinance that lists
all the animals protected was last revised in June 1992.
8.2.7
The Protection of Endangered Species of Animals and Plants
Ordinance (Cap 586) was enacted to align Hong Kong to control regime with the
Convention on International Trade in Endangered Species of Wild Fauna and Flora
(CITES). With effect from 1 December 2006, it replaces the Animals and Plants
(Protection of Endangered Species) Ordinance (Cap 187). The purpose of the
Protection of Endangered Species of Animals and Plants Ordinance is to restrict
the import and export of species listed in CITES Appendices so as to protect
wildlife from overexploitation or extinction. The Ordinance is primarily
related to controlling trade in threatened and endangered species and
restricting the local possession of them.
8.2.8
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 reserved generally for the purpose of nature
conservation.
8.2.9
The amended Town Planning Ordinance (Cap 131) provides for
the designation of coastal Protection Areas, Sites of Special Scientific
Interest (SSSI), Green Belt or other specified uses that promote conservation
or protection of the environment, e.g., Conservation Areas. The authority
responsible for administering the Town Planning Ordinance is the Town Planning
Board.
8.2.10 The enactment of
Marine Parks Ordinance (Cap 476) laid the milestone of marine conservation in
Hong Kong. This Ordinance provides for designation, control and management of
marine parks and marine reserve.
8.2.11 The Peoples
Republic of China (PRC) is a Contracting Party to the United Nations Convention
on Biological Diversity of 1992. The Convention requires signatories to make
active efforts to protect and manage their biodiversity resources. The
Government of the Hong Kong SAR has stated that it will be committed to
meeting the environmental objectives of the Convention (PELB 1996). In 1988
the PRC ratified the Wild Animal Protection Law, which lays down basic
principles for protecting wild animals. The Law prohibits killing of protected
animals, controls hunting, and protects the habitats of wild animals, both
protected and non-protected. The Law also provides for the creation of lists of
animals protected at the state level, under Class I and Class II. There are 96
animal species in Class I and 156 in
Class II. Class I provides a higher level of protection for animals considered
to be more threatened.
8.2.12 The International
Union for Conservation of Nature and Natural Resources (IUCN) Red List of
Threatened Species provides taxonomic, conservation status and distribution
information on taxa that have been evaluated using the IUCN Red List Categories
and Criteria. This system is designed to determine the relative risk of
extinction, and the main purpose of the IUCN Red List is to catalogue and
highlight those taxa that are facing a higher risk of global extinction. The
IUCN Red List also includes information on taxa that are either close to
meeting the threatened thresholds or that would be threatened were it not for
an ongoing taxon-specific conservation programme.
8.2.13 China Red Data
Book of Endangered Species is a joint publication of China National
Environmental Protection Agency (NEPA) and the Endangered Species Scientific
Commission, PRC (ESSC). The first four volumes of this series cover China's
vertebrates (i.e. aves, pisces, amphibia, reptilian and mammalia). The criteria
of categories of species included in these volumes are extinct, extirpated,
endangered, vulnerable, indeterminate and rare. These categories are
basically based on the criteria set out by the IUCN Species Survival Commission
(IUCN-SSC) for its global Red List. However, there are some important
differences. The category "Extirpated" includes those species which
experts believe have been lost from China, although they may be secure in the
other countries. The use of the category "Rare" has been discontinued
by the IUCN-SSC, however, it is used here for those species that have always
been rare in China but are not necessary to be vulnerable or endangered.
8.2.14 CITES is an
international agreement between governments. It aims to ensure that
international trade in specimens of wild animals and plants does not threaten
their survival. Roughly 5,000 species of animals and 28,000 species of plants
are protected by CITES against over-exploitation through international trade.
They are listed in the three CITES Appendices, in which the species are grouped
according to how threatened they are by international trade. Appendix I lists
species that are the most endangered and are threatened with extinction.
Appendix II lists species that are not necessarily now threatened with
extinction but that may become so unless trade is closely controlled. And Appendix
III is a list of species included at the request of a Party that already
regulates trade in the species and that needs the cooperation of other
countries to prevent unsustainable or illegal exploitation.
8.3.1
Existing information about the ecological condition within
the Study Area were reviewed. This
included but not limited to EIA-065/2001 132KV Supply Circuit from Pui O via
Chi Ma Wan Peninsula via Sea Crossing towards Cheung Chau; Extension of
Existing Landfills and Identification of Potential New Waste Disposal Sites
Final SEA Report (Part B: South Cheung Chau Island Landfill; and Improvement
of Fresh Water Supply to Cheung Chau.
Reviewed literature is listed in Section 1.5.1 of Appendix 8.1.
8.3.2
According to the EIA Study Brief No. ESB212/2009,
ecological field surveys were carried out to fill the information gap
identified from reviewed literatures.
Field surveys for terrestrial and freshwater
ecology, with a 4-month duration, were conducted
between May and August 2011 to cover the wet season. The full ecological baseline survey report is
attached in Appendix 8.1, and results of
key findings are summarized in this chapter.
8.3.3
The marine elements of the Project, including the
construction of a new SPS at Kwun Yam Wan, which had once been described in the
Project Profile, were omitted in the design process during the
present EIA study to avoid and minimise impacts. All proposed works elements are now
land-based and no marine works will be involved under the Project. Given that there will be no direct impact on intertidal or subtidal
habitat and the beneficial effects on marine water quality would be brought by
the Project as illustrated in the water quality assessment, assessment on
marine ecology would focus on indirect impacts and the assessment results are
likely positive. After reviewing all
available literatures on baseline information for marine ecology, in particular to
marine mammals, benthic communities, intertidal habitats, and corals as
stipulated in the Study Brief, it was found that the
information, of which the literatures include some recently approved EIA
studies in the area, is up-to-date and sufficient for the assessment purposes. Therefore,
field surveys for marine ecology were not conducted.
8.3.4
Table 8.1 summarizes the methodology of habitat mapping, flora and
fauna surveys carried out in terrestrial and freshwater habitats in the Study
Area of Cheung Chau. Details of survey
methodology are described in Section 1.6 of Appendix
8.1.
Table 8.1 : Summary of the
Methodology for Ecological Baseline Surveys
|
Survey Type
|
Brief Methodology
|
Survey Period
|
|
Habitat and Vegetation
|
Habitat mapping and vegetation
identification through ground truthing in major habitats.
|
Monthly from May to August 2011
|
|
Bird
|
Quantitative (point count and
transect count method) and qualitative (recorded within the Study Area)
survey including day and night surveys covering the wet season.
|
Monthly from May to August 2011
|
|
Mammal
|
Quantitative (active searching
along the survey transect) and qualitative (recorded within Study Area);
including day and night surveys covering the wet season.
|
Monthly from May to August 2011
|
|
Herpetofauna
|
Quantitative (active searching
along the survey transect) and qualitative (recorded within Study Area);
including day and night surveys covering the wet season.
|
Monthly from May to August 2011
|
|
Butterfly
|
Quantitative (point count and transect
count method) and qualitative (recorded within Study Area) survey; including
only day-time surveys covering the wet season.
|
Monthly from May to August 2011
|
|
Odonates
(i.e. Dragonfly & Damselfly)
|
Quantitative (point count and
transect count method) and qualitative (recorded within Study Area) survey;
including only day-time surveys covering the wet season.
|
Monthly from May to August 2011
|
|
Freshwater Aquatic Assemblage
|
Active searching in freshwater
streams,; using hand net and kick sampling; including only day-time surveys
in the wet season.
|
Two times in July and August
2011
|
Terrestrial and Aquatic Ecology
8.4.1
Habitats recorded within the Study Area included young
woodland, plantation, shrubland, grassland, stream, agricultural land/orchard,
developed area/village and coastal area (Figures 1.3a-d and 1.4a-b of Appendix
8.1). Details of existing
ecological baseline conditions for terrestrial and aquatic ecology from
reviewed literature are described in Sections 1.3 - 1.5 of Appendix
8.1. Details of findings from
ecological field surveys are described in Section 1.7 of Appendix
8.1. Based on the ecological
field surveys, it is concluded that the habitats
recorded included young woodland, plantation, shrubland, grassland, stream,
agricultural land/orchard, developed area/village and coastal area. The
ecological value of young woodland was considered to be moderate to high. The
ecological value of shrubland, stream and developed area/village was considered
to be low to moderate. And that of plantation, grassland, agricultural
land/orchard and coastal area was considered to be low. The sites of Cheung Chau STW and Pak She SPS
where the upgrading works would be performed are classified as
Village/Developed Area.
Marine Ecology
8.4.2
As stipulated in the EIA Study Brief (clause 3.4.6.2),
the assessment area for marine ecological impact assessment shall be the same
as the assessment area for water quality impact assessment. The water quality assessment has identified
water quality sensitive receivers (WSRs) within the Southern Water
Control Zone and adjacent areas, and the simulated water quality results in these WSRs due
to the effluent discharge from upgraded Cheung Chau STW under different
scenarios were presented to assess the potential water quality impact. The locations and distributions of these WSRs
were presented in Figure 5.1 and 5.2. Within the coverage of
these WSRs, several recognized sites of conservation importance were found,
including Sham Wan SSSI. There are also
some important intertidal habitats within the coverage of these WSRs, such as
corals previously recorded in Cheung Chau and the nearby islands (Ping Chau,
Lantau and Lamma), Finless Porpoise habitat to the south of Cheung Chau,
mangroves and seagrass beds in Lantau, and horseshoe crab
sites. The marine ecological assessment
would thus follow the coverage of the WSRs and focus on the recognized sites of
conservation importance as well as species and habitats within, including
benthic communities, intertidal habitats, coral communities (Figure 8.1
referred) and marine mammals (Figure 8.2
referred). Sites and habitats outside
the coverage are far away from the Project Site due to the vast size of the
Southern Water Control Zone, and impacts to these sites and habitats would be
unlikely given that there will be no marine works involved in the present
Project.
Marine Mammals
8.4.3
Only two marine mammal species, the
Chinese White Dolphin (Sousa chinensis, also known as Indo-Pacific humpback dolphin,) and Finless
porpoise (Neophocaena phocaenoides)
are resident to Hong Kong. Finless Porpoise is protected locally by the
Wild Animals Protection Ordinance (Cap 170).
It is also categorized as Vulnerable by the IUCN Red
List of Threatened Species, and Appendix I in the CITES. According to Hung (2013), from 2012-2013 Finless Porpoise were mainly sighted in the southern waters of Hong Kong (Figure 8.2). The important porpoise habitats
during 2004-2012 were located to the south of Tai A Chau near Shek Kwu Chau,
the waters between these two islands, the sourth-western and eastern side of
Lamma Island during the dry season and around Po Toi Islands during the wet
season . When comparing the porpoise
distribution in 2012-13 with those from the past five years (i.e. 2007-2008
annual survey to 2011-2012 annual survey), the area between Shek Kwu Chau and
the Soko Islands have been consistently utilized by finless porpoises since
2007-2008. But temporal changes in distribution were also found. Finless porpoises were regularly sighted
between Cheung Chau and Shek Kwu Chau during this period, the sightings of
porpoises were increased in 2012-13 among the past six-year records. However, the sighting maps
during from 2007-2008 annual survey to 2012-2013 annual survey also reveal that
finless porpoise sightings near southern half of Cheung Chau were less frequent
than its adjacent areas including waters between Shek Kwu Chau and Soko Islands
and waters around south Lamma Island. The coastal waters
at northern half of Cheung Chau, where the existing STW and existing outfall
are located, is not considered important for marine mammals.
8.4.4
Chinese White Dolphin also protected locally by the Wild
Animals Protection Ordinance (Cap. 170) and under the Protection of Endangered
Species of Animals and Plants Ordinance (Cap 586). It is listed as Near
Threatened in the IUCN Red List of Threatened Species, and listed in the CITES
Appendix I. In mainland, it is listed as a Grade 1 National Key Protected
Species. In Hong Kong, Chinese White
Dolphins concentrate in the more
estuarine-influenced waters, i.e. all the waters of western Hong Kong. They are present commonly year-round in the
waters north and west of Lantau, and also occur seasonally or in small numbers
to the south and east of Lantau Island, as well as in southern Deep Bay and to
the west of Lamma Island. They are not
present in the waters to the east of Lamma Island, except for occasional
wanderings. From 2012-2013, Chinese White Dolphins were
sighted throughout waters around Lautau and Deep Bay (Hung 2013). Habitat use patterns of dolphins from 2008-12
revealed that their highest densities areas included the west coast of Lantau,
around Lung Kwu Chau, near the northeast corner of airport, Kau Ling Chung and
Yam O. Waters around Cheung Chau
however are not dolphins important habitats. In the 2012-2013 annual marine
mammal monitoring survey, there was no sighting recorded around Cheung Chau,
and the nearest sighting was Soko Islands (ibid). When reviewing the dolphin results from 2006
to 2013, basically there was no dolphin sighting around Cheung Chau during this
duration, except one single sighting on the southeast side of the island in
2006-2007 survey (Hung 2013).
Benthic Communities
8.4.5
Except in eastern and southern shores where the shallow
subtidal habitat is rocky and coral-encrusted, the majority of subtidal seabed
of Hong Kong is soft and comprises an admixture of sand and mud. The detailed composition of the soft sediment
varies from place to place and is one of the main factors that determines the
type of bottom dwelling (benthic) organisms which inhabits the sediment. Soft sediments support a wide range of
bottom-dwelling (benthic) communities and standing crops, and have been long
recognized as valuable feeding areas as they are major food source for demersal
fishery (AFCD website).
8.4.6
A study of benthic assemblages throughout Hong Kong was
undertaken by Shin and Thompson (1982). The study concluded that the western
waters of Hong Kong supports assemblages that are polychaete dominated (over
80%). Results from 2001 territorial-wide
marine benthic survey (CCPC 2002), the eastern and southern waters are more
homogeneous (evenness) in benthic composition and diversity, which reflect
relatively higher ecological importance as compared with the other
regions. However, no species of
conservation importance is recorded.
8.4.7
According to the EIA Study for the CLP cable circuit
project (Mott 2001), it was suggested that the benthic assemblages between Chi
Ma Wan and Cheung Chau (i.e. Admasta Channel) supported relatively low
ecological value assemblages.
8.4.8
Soft-bottom seabed habitat offshore to east Cheung Chau was
investigated by grab sampling during the EIA study for Improvement
of Fresh Water Supply to Cheung Chau (BV 2010), and the results revealed that
no species of conservation importance was found in the area. 59 taxon were
recorded among the 268 benthic organisms collected, including 8 Phyla.
Shannon-Wiener Diversity Index ranged from 1.75 to 3.30, while Pielous
Evenness index ranged from 0.76 to 0.96.
Infauna diversity was relatively low, and all the species recorded
occurred frequently in Hong Kong.
Intertidal Habitats
8.4.9
As described in the study for EIA-065/2001 132 KV Supply
Circuit from Pui O via Chi Ma Wan Peninsula via Sea Crossing towards Cheung
Chau (CLP 2001), the majority of the coastal areas on Cheung Chau have been
reclaimed and lined with vertical artificial seawalls. This is
particularly obvious on the western shores at the populated central portion of
the island. Within the Study Area, the coastlines near Sai Wan, Cheung Chau
Wan and Cheung Chau Typhoon Shelter are all dominated by
artificial seawalls.
8.4.10 Rocky shores and sandy shores are present along the
coastline of the Study Area. Typical exposed rocky shore
communities consist of periwinkles, barnacles and limpets. Encrusting algae are common in low intertidal
zone (William 2003). Typical sandflat
communities consist of numerous epifauna and infauna organisms such as
burrowing crabs, gastropods, bivalves and worms (Chan and Caley 2003).
8.4.11 During the EIA study for Improvement of Fresh
Water Supply to Cheung Chau (BV 2010), intertidal surveys were
performed on Cheung Chau at 8 locations at Tai Kwai Wan
covering artificial seawalls, rocky shores and sandy shores. One of the survey locations was on the
artificial seawalls of the existing STW under the Project. It was found that no species of conservation
importance was recorded during the survey in intertidal habitats (neither hard
nor soft shore habitats). On rocky shores, dominant species included Rock oyster Saccostrea cucullata, Acorn barnacle Tetraclita squamosa, Stalked barnacle Capitulum mitella, and Black mussel Septifer virgatus. All these species are common and abundant
species on typical rocky shore habitats.
On sandy shores, however, only Ghost crab Ocypode
sp. and Clam Donax sp. were recorded,
which are
also common and typical fauna of sandy beaches. While on artificial
seawalls, species composition was similar with those on rocky shores,
but the diversity and abundance of intertidal fauna were
relatively
much lower. (ibid)
Coral Communities
8.4.12 Corals were
previously reported in Cheung Chau at some locations away from urbanized areas,
for examples the headlands at the northeast and southeast of Cheung Chau. Hard
coral communities have been identified in the waters of Tung Wan Tsai (Coral
Beach) (Chan et al. 2005; AFCD 2004),
which is approximately 750 m
from the closest works area. Families
including Siderastreidae, Mussidae, Faviidae and Poritidae have been previously
recorded at Tung Wan Tsai (Chan et al.
2005). Octocorals Dendronephthea, Guaiagorgia,
Stereonephthea and a presently
undescribed species of nephtheid soft coral have also been recorded (AFCD
2004). Moreover, siderastreid Psammocora superficialis, ahermatypic
dendrophylliids Balanophyllia, Tubastraea and Dendrophyllia spp., soft corals (gorgonians) Euplexaura and Echinomuricea,
and corallimorpharian Discosoma have
been reported by AFCD (2004) at Tung Wan Tsai and to the east of Kwun Yam Wan
Beach. In other locations closer to the urbanized areas, no significant coral
record was reported. During the EIA study for Improvement of Fresh Water
Supply to Cheung Chau, dive survey was conducted at a small reclamation
headland at Kwu Yam Wan, but no coral was recorded. In Hong Kong, coral communities are
protected under Protection of Endangered Species of Animals and Plants
Ordinance (Cap 586).
8.5
Evaluation of
Habitats and Species of Ecological Importance
8.5.1
The ecological importance of the habitats and wildlife
identified within the Assessment Area during the surveys are evaluated in
accordance with the EIAO-TM Annex 8 criteria, and presented in Tables
8.2 - 8.9. The ecological
value of young woodland was considered to be moderate to high. The ecological value of shrubland, stream and
developed area/village was considered to be low to moderate. And that of plantation, grassland,
agricultural land/orchard and coastal area was considered to be low.
Table 8.2 : Ecological
Evaluation of Young Woodland within Study Area of Cheung Chau
|
Criteria
|
Young Woodland
|
|
Naturalness
|
Semi-natural dominated by
native plants.
|
|
Size
|
Large patches of young
woodland were found in the hilly northern (behind Tai Kwai Wan San Tsuen),
south-western (in the vicinity of Cheung Chau Public Cemetery) and
south-eastern (i.e. Fa Peng) parts of the Study Area, with an overall area of
approximately 78.4 ha
(37.6% of the total Study Area).
|
|
Diversity
|
Moderate to high floral
diversity (100 plant species recorded) with moderate structural complexity.
Moderate faunal diversity.
|
|
Rarity
|
Bird species of conservation
importance included Black Kite Milvus
migrans, Crested Goshawk Accipiter
trivirgatus, Chinese Goshawk Accipiter
soloensis, Emerald Dove Chalcophaps
indica, Greater Coucal Centropus
sinensis and Chinese Hwamei
Garrulax canorus.
|
|
Re-creatability
|
Habitat characteristics and species
composition are relatively natural although not mature enough. In the absence of disturbance, it would
take 15 - 20 years for the young woodland to be re-created.
|
|
Fragmentation
|
The north patch is largely
continuous, while the close canopy of the southern patches is often opened or
chopped by built-ups.
|
|
Ecological Linkage
|
Not functionally links to
any highly valued habitat in close proximity; but may provide roosting sites
for different fauna. Largely fell
within the Green Belt zone.
|
|
Potential Value
|
With a moderate to high
potential value to become mature woodland if given sufficient time and
protection from disturbances.
|
|
Nursery / Breeding Ground
|
Nil.
|
|
Age
|
15 20 years.
|
|
Abundance / Richness of
Wildlife
|
Moderate to high for birds
and butterflies; low for the other fauna groups.
|
|
Overall Ecological Value
|
Moderate to high.
|
Table
8.3 : Ecological
Evaluation of Plantation within Study Area of Cheung Chau
|
Criteria
|
Plantation
|
|
Naturalness
|
Manmade habitat, dominated
by exotic trees and shrubs.
|
|
Size
|
The total area of this
habitat is approximately 9.5 ha
(4.6% of the total Study Area).
|
|
Diversity
|
Low floral diversity (18 plant
species recorded) with low structural complexity.
Low faunal diversity.
|
|
Rarity
|
One bird species of
conservation importance, Black Kite Milvus
migrans.
|
|
Re-creatability
|
For the plantation woodland
along northern hillsides, it would take about 10 years for the trees to be
re-created.
For the plantation in close
proximity of urban environments, habitat characteristics and species
composition are relatively easy to be re-created.
|
|
Fragmentation
|
Largely fragmented and
isolated except for the northern plantation woodland along hill slopes.
|
|
Ecological Linkage
|
Not functionally linked to
any highly valued habitat in close proximity.
|
|
Potential Value
|
Generally low, but low to
moderate for the plantation woodland in north to become young woodland with
native species as dominant plants if given sufficient time and protection
from disturbances.
|
|
Nursery/ Breeding Ground
|
Nil.
|
|
Age
|
10 years.
|
|
Abundance/ Richness of
Wildlife
|
Low for all fauna groups.
|
|
Overall Ecological Value
|
Low.
|
Table 8.4 : Ecological
Evaluation of Shrubland within Study Area of Cheung Chau
|
Criteria
|
Shrubland
|
|
Naturalness
|
Semi-natural habitats mainly
covered by native species.
|
|
Size
|
Patches were recorded within
the Study Area with an overall area of approximately 16.0 ha (7.7% of the total Study
Area).
|
|
Diversity
|
Moderate diversity of plants
(67 species) with moderate structural complexity.
Moderate faunal diversity.
|
|
Rarity
|
Bird species of conservation
importance included Black Kite Milvus
migrans, Greater Coucal Centropus
sinensis and Chinese Hwamei Garrulax
canorus.
|
|
Re-creatability
|
In the absence of
disturbance, it would take 5 - 10 years for the shrubland to be re-created.
|
|
Fragmentation
|
Relatively fragmented, in
particular to those patches surrounded by the developed areas.
|
|
Ecological Linkage
|
Not functionally linked to
any highly valued habitat, bordering young woodland in close proximity. Largely fell within the Green Belt zone.
|
|
Potential Value
|
Low to moderate to become
mature shrubland and then young woodland if given sufficient time and
protection from disturbance.
|
|
Nursery/ Breeding Ground
|
Nil.
|
|
Age
|
5 10 years.
|
|
Abundance/ Richness of
Wildlife
|
Moderate for butterflies and
birds, low for the other fauna groups.
|
|
Overall Ecological Value
|
Low to moderate
|
Table 8.5 : Ecological
Evaluation of Grassland within Study Area of Cheung Chau
|
Criteria
|
Grassland
|
|
Naturalness
|
Natural succession would be
frequently impeded by disturbances such as hill fires.
|
|
Size
|
The total area of this
habitat is approximately 6.9 ha
(6.9% of the total Study Area).
|
|
Diversity
|
Relatively low diversity of
plants (37 species) with low structural complexity.
Low faunal diversity.
|
|
Rarity
|
No flora or fauna species of
conservation importance were found in this habitat.
|
|
Re-creatability
|
Readily re-creatable.
|
|
Fragmentation
|
Concentrated in the northern
hilly areas, generally not fragmented.
|
|
Ecological Linkage
|
Not functionally linked to
any highly valued habitat, bordering young woodland and shrubland located at
lower levels. Largely fell within the
Green Belt zone.
|
|
Potential Value
|
Subject to practice of
management and level of disturbance (e.g. hill fires).
|
|
Nursery/ Breeding Ground
|
Nil.
|
|
Age
|
Very young.
|
|
Abundance/ Richness of
Wildlife
|
Low for all fauna groups.
|
|
Overall Ecological Value
|
Low.
|
Table
8.6 : Ecological
Evaluation of Stream within Study Area of Cheung Chau
|
Criteria
|
Stream
|
|
Naturalness
|
Stream at Shui Hang: generally natural.
Stream at Fa Peng: may receive excessive fertilizer from
nearby farmlands in upstream section.
|
|
Size
|
Total area of this habitat is 0.3 ha, accounting for 0.1% of the total Study Area
(in terms of length, 159.9m for the stream at Shui Hang and 476.3 m for the stream at Fa
Peng).
|
|
Diversity
|
Moderate diversity of plants (32 species) given its small
area.
Low to moderate diversity of amphibian species, low
diversity of other fauna.
|
|
Rarity
|
No flora or fauna species of conservation importance were
found in this habitat.
|
|
Re-creatability
|
Low re-creatability, the characteristic of natural stream
banks and stream bed could be recreated through the incorporation of
ecologically friendly stream design, but the ecological value / functions
will be less when compared with natural stream.
|
|
Fragmentation
|
Not applicable.
|
|
Ecological Linkage
|
Not functionally linked to any highly valued
habitat. Nevertheless, banks of the
Shui Hang river integrated into the young woodland in close proximity.
|
|
Potential Value
|
Moderate in general if
provided with sufficient time, deduction in fertilizer input and protection
from disturbance, etc.
|
|
Nursery / Breeding Ground
|
Nil.
|
|
Age
|
Not applicable.
|
|
Abundance / Richness of
Wildlife
|
Low to moderate for
freshwater assemblage, low for the other fauna groups.
|
|
Overall Ecological Value
|
Low to moderate.
|
Table 8.7 : Ecological
Evaluation of Agricultural Land/Orchard within Study Area of Cheung Chau
|
Criteria
|
Agricultural Land / Orchard
|
|
Naturalness
|
Man-made habitat actively cultivated
in most area except some small plots in the agricultural land near Self Help
Care Village.
|
|
Size
|
Two patches of agricultural
lands often associated with small sized orchards were found located within
the valley east of the Self Help Care Village as well as in the lowland area
below Ming Fai Road in Fa Peng, with an overall area of approximately 1.6 ha (0.8% of the total
Study Area).
|
|
Diversity
|
Moderate diversity of crop
plant species, in particular in the Fa Peng Agricultural land.
Low fauna diversity.
|
|
Rarity
|
One bird species of
conservation importance, Black Kite Milvus
migrans.
|
|
Re-creatability
|
Readily re-creatable.
|
|
Fragmentation
|
Relatively fragmented given
the small size of the two patches.
|
|
Ecological Linkage
|
Surrounded by young
woodland, but not functionally linked to any highly valued habitat.
|
|
Potential Value
|
Highly depending on the
management practice of land owners, i.e. wet agricultural land often has higher
ecological value due to the comparatively high diversity of fauna it
supports.
|
|
Nursery/ Breeding Ground
|
Nil.
|
|
Age
|
Not applicable.
|
|
Abundance/ Richness of
Wildlife
|
Low to all fauna groups.
|
|
Overall Ecological Value
|
Low
|
Table 8.8 : Ecological
Evaluation of Developed Area/Village within Study Area of Cheung Chau
|
Criteria
|
Developed Area / Village
|
|
Naturalness
|
Man-made habitat dominated
by ornamental trees and fruit trees.
|
|
Size
|
The largest habitat within
the Study Area with an overall area of approximately 85.6 ha (41.1% of the total
Study Area).
|
|
Diversity
|
Moderate to high floral
diversity (136 plant species recorded).
Moderate faunal diversity.
|
|
Rarity
|
No flora species of
conservation importance, but one OVT (Chinese Banyan Ficus microcarpa, Registration No.: LCSD Is/4) found outside the
Pak Tai Temple.
Bird species of conservation
importance included Black Kite Milvus
migrans and Emerald Dove Chalcophaps
indica.
One reptile species of
conservation importance, Chinese Cobra Naja
atra, found in front of a village house along Fa Peng Road.
|
|
Re-creatability
|
Readily re-creatable.
|
|
Fragmentation
|
Largely continuous and concentrated
in the central part of the Study Area, some village houses or other rural
settlements scattered in the northern and southern hilly areas.
|
|
Ecological Linkage
|
Not functionally linked to
any highly valued habitat, but bordering nearly all of the other habitats
within the Study Area.
|
|
Potential Value
|
Low.
|
|
Nursery / Breeding Ground
|
Nil.
|
|
Age
|
Not applicable.
|
|
Abundance / Richness of
Wildlife
|
Moderate to high for birds,
moderate for butterflies and herpetofauna, low for the other fauna groups.
|
|
Overall Ecological Value
|
Low to moderate.
|
Table 8.9 : Ecological
Evaluation of Coastal (Intertidal) Area and
Marine Area within Study Area of Cheung Chau
|
Criteria
|
Coastal
(Intertidal) Area
|
Marine
Area
|
|
Naturalness
|
Rocky
shore: largely natural, with a minor proportion of artificial seawalls.
Sandy
shore: disturbed by beach activities and littering.
Seawalls
are artificial.
|
Natural
in general but disturbed by human activities.
|
|
Size
|
Total
area of this habitat is 10.0 ha
(4.8% of the total Study Area).
|
NA
|
|
Diversity
|
Low
in plant species diversity (20 plant species recorded) and structural
complexity.
Low
in fauna diversity.
|
Diversity
and evenness of the benthic composition were relatively high in the southern
and eastern Hong Kong waters, but a low diversity on benthic communities was
recorded in east Cheung Chau.
|
|
Rarity
|
One bird species of conservation
importance, Black Kite Milvus migrans.
|
No species of conservation
importance was found in benthic habitat; while Finless porpoises are recorded
in the southern waters of Hong Kong, ranging from southwest Lantau to the
west to Po Toi and Ninepins areas to the east. The Assessment Area also
covers some habitats of Chinese White Dolphins, but only sporadic sighting
records around Cheung Chau.
|
|
Re-creatability
|
Difficult to be re-created
except artificial seawalls.
|
Difficult to be re-created.
|
|
Fragmentation
|
Located continuous along the
periphery of the Study Area.
|
The habitat is not
fragmented.
|
|
Ecological Linkage
|
Not functionally linked to
any highly valued habitat in close proximity.
Rocky shore mainly bordering young woodland and shrubland, while sandy
shore mainly bordering developed area/village.
|
The habitat is generally
linked with the open sea and is not functionally linked to any high value
habitat in a significant way
|
|
Potential Value
|
Low.
|
Low.
|
|
Nursery/Breeding Ground
|
Nil.
|
Nil.
|
|
Age
|
NA
|
NA
|
|
Abundance /Richness of
Wildlife
|
Low for all fauna
groups.
|
Low for benthic fauna
groups, relatively high for Finless Porpoise during winter and spring months.
|
|
Overall Ecological
Importance
|
Low
|
Moderate due to vicinity of
the Finless Porpoises habitat range.
|
8.5.2
A list and evaluation of the species of conservation
importance recorded during ecological baseline surveys within the Study Area,
according to the EIAO-TM, are given in Table 8.10. Seven fauna species were considered of
conservation importance, including Black Kite Milvus migrans, Crested Goshawk Accipiter
trivirgatus, Chinese Goshawk Accipiter
soloensis, Emerald Dove Chalcophaps
indica, Greater Coucal Centropus
sinensis, Hwamei Garrulax canorus
and Chinese Cobra Naja atra. The locations of these species of
conservation importance, whenever available, are presented in Figures
1.3a - 1.3d of Appendix 8.1.
8.5.3
Marine fauna of conservation importance including Finless
porpoises and hard corals were addressed from literature reviews, and are
evaluated in Table 8.10.
8.5.4
Black Kite, Greater Coucal and Chinese Cobra occur in a
variety of habitats. Chinese Goshawk is
mainly found in lightly wooded areas and marshes. Crested Goshawk and Emerald Dove are mainly
found in woodland. Hwamei is mainly
found in woodland and hillsides with thick scrub cover.
Table 8.10 : Evaluation of
Species of Conservation Importance recorded within
Study Area of Cheung Chau during Ecological Baseline Surveys
|
Species
|
Location and Activities (if
any)
|
Protection Status
|
Distribution
|
Commonness in HK
|
|
Birds*
|
|
Black Kite Milvus migrans
|
Flew over or perched at
young woodland, plantation, shrubland, agricultural land/orchard, developed
area/village and coastal area of the Study Area.
|
Appendix II of CITES; Class
II Protected Animal of PRC; Protected under Protection of Endangered Species
of Animals and Plants Ordinance (Cap. 586).
|
Found in a wide variety of
coastal and inland habitats, including small islands, sea-coasts, intertidal
mudflat, fish ponds, reservoirs, landfills and grassy hillsides at all
altitudes; East Eurasia.
|
Common and widespread.
Resident and Winter Visitor
|
|
Crested Goshawk Accipiter trivirgatus
|
Flew over the young woodland
in the north of the Study Area.
|
Appendix II of CITES; Class
II Protected Animal of PRC; Listed as
Rare in China Red Data Book; Protected under Protection of Endangered
Species of Animals and Plants Ordinance (Cap. 586).
|
Widespread in the forest and
mature woodlands of the New Territories in Hong Kong, widespread in PRC.
|
Locally uncommon resident
|
|
Chinese Goshawk Accipiter soloensis
|
Flew over the young woodland
in the north of the Study Area.
|
Appendix II of CITES; Class
II Protected Animal of PRC; Protected under Protection of Endangered Species
of Animals and Plants Ordinance (Cap. 586).
|
Breeds in Ussuriland, Korea,
and much of China, and winters from southeast China through Indochina, the
Philippines and Indonesia to New Guinea. In Hong Kong, previously recorded in
Tsim Bei Tsui, Kadoorie Farm and
Botanic Garden, and Tai Po Kau
|
Uncommon passage migrant in
Hong Kong.
|
|
Emerald Dove Chalcophaps indica
|
Flew through the developed
area and finally perching at the young woodland near Ping Chong Road during
the survey.
|
Listed at Vulnerable in
China Red Data Book
|
South Asia and Australia.
Favours thick woodland and good secondary growth.
|
Scarce resident in Hong Kong
|
|
Greater Coucal Centropus sinensis
|
Calling heard at several
spots in young woodland and shrubland
|
Class II Protected Animal of
PRC; Listed as Vulnerable in China Red Data Book.
|
Resident throughout the
Oriental region, apart from Taiwan, the Philippines and Sulawesi; Found in
many types of habitats in Hong Kong.
|
Common and widespread
resident in Hong Kong.
|
|
Hwamei Garrulax canorus
|
Calling heard in young
woodland and shrubland.
|
Appendix II of CITES.
|
North Indo-China to China
and South China; Found in woodland and hillsides with thick scrub cover.
|
Common breeding resident in
Hong Kong
|
|
Reptile
|
|
Chinese Cobra Naja atra
|
Found in front of a village
house along Fa Peng Road.
|
Appendix II of CITES; Listed
as Vulnerable in China Red Data Book; Protected under Protection of
Endangered Species of Animals and Plants Ordinance (Cap. 586).
|
Usually occurs in different
kinds of habitat such as woodlands, shrublands, grasslands and mangroves.
|
Unclear
|
|
Marine Fauna
|
|
Finless porpoise Neophocaena phocaenoides
|
Recorded in southeast and southwest Cheung Chau, but not within their important habitats
|
WAPO
|
Can be found in the southern
and eastern waters of Hong Kong
|
NA
|
|
Chinese White Dolphin
|
Only sporadic sightings near Cheung
Chau
|
WAPO
|
Mainly in West Lantau and North
Lantau,
|
NA
|
|
Hard corals
|
Eastern Cheung Chau
|
Cap 586
|
Mainly grow along the northeastern
and eastern shores, form communities in shallow coaster water.
|
Common
|
Note:
* All
birds in Hong Kong are protected under the Wild Animals Protection Ordinance
(Cap 170).
8.6.1
The Project will comprise the expansions, improvement and
upgrading of the existing sewerage system at Cheung Chau. The extent of the Project Site is shown in Section
2 and Figures 1.1 - 1.2 of Appendix 8.1. Major project elements include:
Ÿ
new gravity village
sewers for 9 villages and Cheung Chau Town Centre; and
Ÿ
upgrading of Cheung
Chau STW and Pak She SPS.
8.6.2
All the sewers will be constructed along existing road and
paths within developed area using open-cut method. A section of the deep sewer alignment will
run along Ming Fai Road. Currently there
is a footbridge on Ming Fai Road near Kwun Yam Wan Beach, which spans across a
stream (i.e. Fa Peng Stream) and leaves the streambed
unmodified. The sewer alignment will
cross Fa Peng Stream through this existing
footbridge and thus it will be elevated above the stream and therefore the
stream will not be directly encroached.
8.6.3
Upgrading works of the SPS and sewage treatment work will
take place within the existing structure located within developed
area/village. Construction of SPS will
take place within developed area/village.
8.6.4
The potential ecological impacts caused by the project are
identified and evaluated in the following sections.
Construction Phase
Direct Impact Habitat
Loss
8.7.1
The proposed project will only cause temporary loss of
about 3 ha of
developed area/village for both options.
There will be no loss of intertidal habitat or coral communities as no
marine works are proposed. No important
habitat or species of conservation importance will be lost to the proposed
project. A summary of habitat loss is
provided in Table 8.11.
8.7.2
Removal of existing vegetation and trees will be required during
site formation for the STW upgrading works.
Plant species associated with developed area/village habitat are all
common species; no species of conservation importance will be affected.
8.7.3
No important habitat or species of conservation importance
listed in Table 8.10 will be lost to or affected by the proposed project. Losses of habitats and their associated flora
and fauna are considered minor impacts due to the limited ecological importance
and temporary nature.
Table
8.11 : Estimated
Habitat Loss Caused by the Project
|
Items
|
Estimated habitat loss (ha) (Developed
area/village only)
|
|
Proposed Sewers*
|
1.18
|
|
Proposed upgrading of Cheung Chau STW
|
1.59
|
|
Proposed upgrading of Pak She SPS
|
0.03
|
|
Deep Sewer
|
0.15
|
|
Temporary Works Area
|
0.14
|
|
Total
|
3.09
|
Note:
* gravity sewer + rising main,
assuming a 2m works boundary during construction
Indirect Impact
Disturbance
8.7.4
Indirect construction impacts include disturbance of flora and
fauna due to noise and dust during construction. Noise and dust will mainly affect areas
adjacent to the works areas, which are mostly developed area/village. Fauna inhabiting this type of habitat are
likely to be disturbance tolerant.
Disturbance during construction phase will be short-term and
localised. Due to the temporary and
localized nature of the impacts, potential impacts to flora and fauna are
ranked as minor. Dispersion of dust and
noise generated during construction can be minimized by good site
practice. Should the Deep Sewer Option
be selected, trenchless construction method is recommended to reduce the extent
of road opening works.
Indirect Impact - Site
Runoff
8.7.5
In the present proposed Project, all construction works are
minor in scale and would take place within proposed working area. With the implementation of adequate
mitigation measures at construction sites and provision of sediment removal
facilities, it is anticipated that site runoff would not occur. The adjacent marine waters (mainly near the
Cheung Chau STW, the Cheung Chau Typhoon Shelter, and the Tung Wan and Kwun Yam
Wan areas) are not identified as of special ecological or conservation
value. Good site practice and precautionary
measures will be implemented to avoid the potential impact due to runoff.
8.7.6
Finless Porpoises, Chinese White Dolphins, and coral
communities were recorded at the marine environment. Considering that the Project is localised in
nature, all works are terrestrial based.
The potential impacts are further reduced significantly since the
original proposed SPS in Kwun Yam Wan is removed. Therefore, potential impacts on this marine
fauna are considered to be minor.
With the implementation of site runoff control and good site practice,
potential impact on water quality hence coral communities should not
arise.
8.7.7
The concentration of suspended sediment fluxes naturally in
the marine environment, and fish has developed some adaptative behaviours (e.g.
clearing of gills, swimming to clear area) to tolerate changes in suspended
solid and polluted drainage water. With
the implementation of adequate construction site drainage and provision of
sediment removal facilities, potential impact of unacceptable water quality
should not arise. The potential impacts to the aquatic invertebrate and fish
are considered to be insignificant.
Indirect impact Accidental
Spillage of Chemicals
8.7.8
For marine ecology, as the adjacent
marine waters are not identified as of special ecological or conservation value, and there is no marine works under the Project, there would not be any
associated marine traffic, and no increase in the risk of chemical spillage
from vessels. For terrestrial ecology
however, there is still an increased risk of
small-scale oil or chemical (construction works solvent) spills from the construction sites during the construction phase. As all construction works are minor in scale and would take
place within proposed working area, with the implementation of adequate
construction site practices and management, it is
anticipated that the chemical spillage of significant
scale would
not occur. Because of the small volumes
of such materials involved, this risk is considered insignificant.
Operation Phase
Direct Impact - Permanent
Habitat Loss
8.7.9
The sewers will be underground and the SPS is built on
existing developed area/village. There
will be no permanent loss of important habitat.
Indirect Impact - Water
Quality Changes (normal operation)
8.7.10 The water quality
parameters (including annual 90% depth-average DO, 90% bottom DO, TIN, SS, UIA,
E.coli and BOD5) in the
identified WSRs during the baseline conditions (i.e. the operation of the
existing STW) and the normal operation of the upgrade STW were presented in
Section 5.6 and compared. It was found
that incompliance of the TIN will occur in both the dry and wet seasons under
the baseline condition as well as the normal operation. But the incremental difference between the
two scenarios indicated improvements (increase of DO, and reductions in TIN,
UIA, SS, and BOD5 and E.coli)
in both dry and wet seasons. Upon
completion of the upgrading works, a relative improvement of water quality is
expected to occur to marine waters near the Cheung Chau area, especially near
the Cheung Chau Wan area. Reductions in
concentrations of a number of water quality parameters including DO, TIN, UIA,
SS, BOD5 and E.coli were
predicted. No adverse water quality
impact is anticipated under the normal operating conditions of the upgraded
Cheung Chau STW. An improvement on water
quality and thus positive impacts to aquatic ecology will be anticipated. Under this project, no effluent with disinfection will be discharged to
the sea. As stated in Section 2.7, there is a proposed effluent reuse
scheme for a portion of treated effluent under the Project. Only the portion of
treated effluent which will be reused under this scheme, i.e. 200m3/day,
will be processed by chlorination in a separated disinfection tank before being
conveyed for reuse within the STW. All effluent discharged via outfall, i.e.
the remaining portion of treated effluent not for reuse purposes, would not go
through chlorination process. As the reused effluent and the discharged
effluent will be separated and the chlorination is limited to the reused
portion, there will be no chlorine going into the sea with the discharges. Therefore, there will be no water quality
impact associated with disinfection activities.
Indirect Impact - Water
Quality Changes (Emergency Discharge from STW)
8.7.11 In case of
operational failure of the Cheung Chau STW, raw sewage might bypass the
wastewater treatment unit and be directly discharged into the marine water.
Water quality assessment assesses the scenario of the STW emergency discharge
in case of the STW operational failure.
Emergency discharge might cause deterioration in water quality and
adverse impact on aquatic and intertidal communities. The water quality results indicated that the
impact from emergency discharge of untreated effluent from the upgraded STW
would be insignificant for majority of the study area in terms of DO, TIN, UIA,
SS, BOD5 and E.coli
concentrations. (see Section 5.6.24). There will be no adverse incremental
difference at all WSRs related to corals (C1 to C15) during the dry season (see
Table 5.15,
Section 5.6.34). Decrease of E.coli was observed in these WSRs (C1 to
C15) in wet season (see Table
5.16). In general, the adverse impact on water
quality is expected not significant during the emergency discharge of untreated
sewage from the STW. No adverse impact
is anticipated either to long term water quality conditions of the marine
receiving water. With regular maintenance and checking of plant equipment,
chances of occurrence of the incident will be very low. The potential ecological impacts to aquatic
and marine ecology will be temporary in nature and is anticipated to be Insignificant.
As there will be no adverse impact on the WSRs around Cheung Chau and in the
vicinity, there will be no adverse impacts on other marine ecological resources
farther away including Sham Wan SSSI, Finless Porpoise habitat to the south of
Cheung Chau, mangroves and seagrass beds in Lantau, and horseshoe crab
sites.
Indirect Impact - Water
Quality Changes (Emergency Discharge from SPS)
8.7.12 Sewage overflow
may occur if pumps fail or if there is an interruption to the electrical supply
powering the pumps. Sewage overflow may
enter the nearby watercourse and intertidal habitat, causing deterioration in
water quality and adverse impact on aquatic and intertidal communities. Corals are recorded at Tung Wan Tsai and Kwun
Yam Wa of east side of Cheung Chau, while the two sewage pumping stations are
located on the west side of Cheung Chau.
The overflow of raw sewage from Pak
She SPS will be diverted to the Cheung Chau STW for normal
treatment. In case of operational
failure of the Cheung Chau STW, raw sewage might bypass the wastewater
treatment unit and be directly discharged into the marine water. Water quality
assessment assesses the scenario of the STW emergency discharge in case of the
STW operational failure. The simulated concentrations near the STW will increase
sharply right after the emergency discharge. Potential impact of the Cheung Chau STW emergency discharge
on water quality was predicted to occur only to limited local areas close to
the STW discharge outfall. The impact of
the emergency discharge will last for a short duration, decreases rapidly from
its peak, impact returns to the normal background level in less than 12 hours
after the emergency discharge is ceased. No adverse impact
is anticipated either to long term water quality conditions of the marine
receiving water. With regular maintenance and checking of plant equipment,
chances of occurrence of the incident will be very low. With the implementation of contingency plan
and remedial measures, the potential ecological impacts to aquatic and marine
ecology will be temporary in nature and is anticipated to be insignificant. Similarly, as there will be no adverse impact
on the WSRs around Cheung Chau and in the vicinity, there will be no adverse
impacts on other marine ecological resources farther away.
Indirect
Impact Noise
and Other Disturbance generated by Operation Activities
8.7.13
Noise might be generated
during the operation stage (e.g. operation of machines inside the SPS and STW). It is however anticipated that noise from the proposed Project would be of low level (as its operation only involves machines confined
within buildings) and only the immediately adjacent areas are concerned. The pumping stations and the STW are not
close to any terrestrial
natural habitats sensitive to noise disturbance, and thus the potential impact would be
insignificant. For impacts on marine fauna, the potential is even more remote as those
facilities are all land-based.
8.8
Impact Avoidance and Mitigation Measures
8.8.1
The marine elements of the Project, including the
construction of a new SPS at Kwun Yam Wan, which had once been described in the
Project Profile, were omitted in the design process during the
present EIA study to avoid and minimise impacts. All proposed works elements will
be
land-based and no marine works will be involved under the Project. Direct impact on intertidal or subtidal habitat will be avoided.
8.8.2
Deep Sewer Option as described in Section 2.4 is proposed
to replace the construction of Kwun Yam Wan SPS for conveying sewage from Fa
Peng and Chi Ma Hang. Potential adverse
marine ecological impacts due to the construction and operation of Kwun Yam Wan
SPS can be eliminated.
8.8.3
The 6 nos. of affected trees will be transplanted as far as
possible. Compensatory planting in
accordance with ETWB TCW 3/2006 - Tree Preservation would be implemented to
fully compensate for the tree and vegetation loss if transplanting of trees is
not feasible or not preferable. Mitigation
measures on potential landscape impacts will be addressed in Section 11.
8.8.4
The overall ecological impact is ranked as minor, and other
than environmental protection measures and good site practice proposed in air, water,
noise and waste chapters, no specific ecological mitigation is required.
8.9.1
Due to small scale, temporary nature and limited ecological
value of habitat affected, the residual impact is short term and minimal, and
considered acceptable. Similar habitats
will be created upon completion of works.
In long term, there will be an overall improvement in water quality for
marine waters near the Project site as a result of the upgrading works, hence a
positive effect on the habitat for the marine ecology.
8.10.1 Given the limited
sizes of the works areas, the ecological value of the habitats affected by the
works areas is limited, no specific ecological monitoring is required during
construction phase. Weekly site
inspection should be carried out by the environmental team to ensure the
implementation of mitigation measures and proper site practice proposed to
safeguard air and water quality as well as noise impacts.
8.11.1 The Project will only
temporarily affect small sizes of habitat of limited ecological value
habitats. No important habitat or
optimal habitats of fauna species of conservation importance will be lost to
the Project. Affected trees will be
transplanted. The overall ecological
impact is ranked as minimal and the long term effect is positive with respect
to marine ecology as a result of the improvement in marine water quality due to
the upgrading works.
8.11.2 Besides good site
practices, no other major mitigation measure for ecology is required. With the regular site inspection performed by
the Environmental Team, no specific ecological monitoring programme is needed.
8.12
References
Ÿ
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