This section presents the baseline
condition of ecological resources within the Study Area ([1]), and findings of the marine ecological
impact assessment associated with the construction and operation of the
Project. Measures required to mitigate
any identified adverse impacts are recommended, where appropriate.
The criteria for evaluating marine
ecological impacts are laid out in the EIAO-TM
as well as the EIA Study Brief (No. ESB-126/2005). Annex
16 of the EIAO-TM sets out the
general approach and methodology for the assessment of marine ecological impacts
arising from a project or proposal. This
assessment allows a complete and objective identification, prediction and
evaluation of the potential marine ecological impacts. Annex 8
of the EIAO-TM recommends the
criteria that can be used for evaluating marine ecological impacts.
Legislative requirements and evaluation
criteria relevant to the study for the protection of species and habitats of
marine ecological importance are:
·
Marine Parks Ordinance (Cap 476);
·
Wild Animals Protection Ordinance (Cap 170);
·
Protection of Endangered Species of
Animals and Plants Ordinance (Cap 586);
·
Town Planning Ordinance (Cap 131);
·
·
The Technical Memorandum on Environmental
Impact Assessment Process under the Environmental Impact Assessment Ordinance
(EIAO-TM);
·
United Nations Convention on Biodiversity
(1992);
·
Convention on Wetlands of International
Importance Especially as Waterfowl Habitat (the Ramsar
Convention); and
·
PRC Regulations and Guidelines.
Details on each of the above are presented
below.
The Marine
Parks Ordinance provides for the designation, control and management of
marine parks and marine reserves. It
also stipulates the Director of Agriculture, Fisheries and Conservation as the
Country and Marine Parks Authority which is advised by the Country and Marine
Parks Board. The Marine Parks and Marine Reserves Regulation was enacted in July
1996 to provide for the prohibition and control certain activities in marine
parks or marine reserves.
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 including all cetaceans are protected under
this Ordinance, as well as certain reptiles (including all sea turtles),
amphibians and invertebrates. The Second
Schedule of the Ordinance that lists all the animals protected was last revised
in June 1997.
The Protection
of Endangered Species of Animals and Plants Ordinance (Cap 586) was enacted
to align
The recently amended Town Planning Ordinance (Cap 131) provides for the designation of
areas such as “Coastal Protection Areas”, “Sites of Special Scientific Interest
(SSSIs)”, “Green Belt” and "Conservation Area”
to promote conservation or protection or protect significant habitat.
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
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 ecological impacts.
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 Special Administrative Region (HKSAR) has stated
that it will be “committed to meeting the environmental objectives” of the
Convention (PELB 1996).
The Convention
on Wetlands of International Importance Especially as Waterfowl Habitat
(the Ramsar Convention) applies in the HKSAR. The Convention requires parties to conserve
and make wise use of wetland areas, particularly those supporting waterfowl
populations. Article 1 of the Convention
defines wetlands as "areas of marsh, fen, peatland
or water, whether natural or artificial, permanent or temporary, with water
that is static or flowing, fresh, brackish or salt, including areas of marine
water the depth of which at low tide does not exceed six meters." The Mai Po/Inner Deep Bay wetland was
declared a Wetland of International Importance (“Ramsar
site”) under the Convention in 1995.
The PRC in 1988 ratified the Wild Animal Protection Law of the PRC,
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.
With reference to
the footprint of the proposed biodiesel plant and the results of water quality
assessment (see Section 6), any
potential direct or indirect impacts to marine ecological sensitive receivers
that may be caused by construction and operation of the Project are likely to
occur within 500 m from the Project Site boundary. Therefore, the Study Area of the Marine Ecological Impact Assessment is
defined as the area within a 500 m radius of the Project site boundary to
ensure adequate coverage for the purpose of assessment (Figures 7.6a and 7.6b). The Study Area consisted of both artificial
shoreline of the TKOIE and natural shoreline of Fat Tong Chau. Information on marine ecological resources
within the Study Area is extracted from relevant literature and past marine
ecological surveys within Tseung Kwan O, which are
subsequently used for the Marine
Ecological Impact Assessment.
A literature review was conducted to
determine the existing marine ecological conditions within the Study Area to
identify habitat resources and species of potential importance. The local literature reviewed included:
·
EIA
Report for SENT Landfill Extension Feasibility Study ([2]) ;
·
Porcupine! (Newsletter of Department of Ecology &
Biodiversity,
·
Ecological
Study for SENT Landfill Extension - Final Report ([4]);
·
Further Development of Tseung
Kwan O Feasibility Study ([5]);
·
SENT Landfill Study - Final Report ([6]);
and
·
Field Guide to Hard Corals of
Based on the literature review, existing
information on subtidal marine ecological resources
within the Study Area is limited. Data
on subtidal marine ecological resources are only
available for Fat Tong Chau. The
underwater dive surveys conducted in 1999 and 2003, with findings presented in
the Area 131 Further Ecological Study Report and the HATS Dive Survey Report
respectively ([8]), indicated that Fat Tong Chau harboured
very few hard corals (i.e. Porites sp. and Cyphastrea sp.).
Nevertheless, soft corals and gorgonians including Echinomuricea sp., Euplexaura sp., Anthogorgia sp., Dendronephthya
sp., Menella
sp. and Echinogorgia
sp., were encountered frequently and occurred in moderate abundance.
A more recent dive survey was carried out
by ERM at Fat Tong Chau in 2005([9])
with the collection of
semi-quantitative data on subtidal hard bottom
assemblages using Rapid Ecological Assessment (REA). Results of the REA survey indicated the
presence of isolated hard coral colonies at subtidal
habitats of Fat Tong Chau. Both the
abundance and diversity of the hard coral community were reported as low, with
only nine hard coral species from four hermatypic
coral families (ie Faviidae, Merulinidae, Poritidae
and Siderastreidae)
and one ahermatypic genus – Tubastrea sp. recorded. All hard
coral species recorded are commonly found in
Information on the
subtidal soft bottom assemblages in the vicinity of
the Project area is available from the Consultancy
Study on Marine Benthic Communities in Hong Kong ([10]). One sampling station (Station 85) is close to
the proposed works area and data extracted from the station can be considered
to be representative of the assemblages within the proposed Project area.
According to the
findings of the Consultancy Study,
the substratum of the sampling station is covered by very fine sand and/or
silt. Their benthic assemblages are
typical of Hong Kong waters and similar to benthic assemblages in majority of
other subtidal habitats in
From the
literature review, it is found that no existing information was available on
the intertidal habitats within the Study Area.
As revealed by the
literature review, information on the marine ecological resources within the
Study Area is limited to data from several studies ([11])
([12]) on the coral communities at Fat Tong Chau. No existing information is available on the subtidal and intertidal habitats along the artificial
shoreline within the Study Area. To fill
these information gaps for the baseline marine ecological conditions, marine
ecological baseline surveys were carried out within the Study Area in April
2008.
Marine ecological baseline surveys were
carried out to characterise the existing marine ecological conditions of the
Study Area. The surveys were designed to
provide an update of the physical and ecological attributes of the Study Area
and address the data gaps identified in literature review. The intertidal and dive surveys focused on
the remaining natural shoreline habitat and those areas which will be directly
impacted by the proposed Project.
The following marine ecological baseline
surveys were undertaken:
·
Subtidal (dive) survey; and
·
Intertidal
survey
A series of Rapid
Ecological Assessment (REA) surveys were conducted to investigate the subtidal sessile benthos of the natural shoreline and
artificial seawall within the Study Area (see Figure 7.6a). An initial qualitative reconnaissance survey
was conducted along the natural shoreline and artificial seawall within the
Study Area. During the survey, the
position and number of transects (T1 – T8) were decided upon, on site.
The standardised semi-quantitative Rapid
Ecological Assessment (REA) – survey technique was used to assess the benthic
communities of the study location. This
technique is now one of the standard practices for EIA marine baseline surveys
in Hong Kong and has been modified from the standardised REA survey technique
established for the assessment of coral communities on the Great Barrier Reef ([13])
for marine environment of
Hong Kong ([14]).
The REA methodology
encompasses an assessment of the benthic cover (Tier I) and taxon
abundance (Tier II) undertaken in a swathe ~ 4 m wide, 2 m either side of each
transect. The belt transect width is
dependent on underwater visibility experienced and for Hong Kong generally
consists of a swathe ~2 m wide, 1 m either side of the each transect. An explanation of the two assessment
categories (Tiers) used in the survey is presented below.
Upon the completion of each
survey transect, five ecological and seven substratum attributes were assigned
to one of seven standard ranked (ordinal) categories (see Tables 7.6a and 7.6b).
Table 7.6a Categories to be used in the Surveys - Benthic Attributes
|
Ecological |
Substratum |
|
Hard coral |
Hard substrate |
|
Dead standing coral |
Continuous pavement |
|
Soft coral |
Bedrock |
|
Black coral |
Rubble |
|
Macroalgae |
Sand |
|
Turf algae |
Silt |
|
|
Large boulders (>50 cm) Small boulders (<50 cm) |
Table 7.6b Categories to be used in the Surveys -
Ordinal Ranks of Percentage Cover
|
Rank |
Percentage Cover (%) |
|
0 |
None recorded |
|
1 |
1-5 |
|
2 |
6-10 |
|
3 |
11-30 |
|
4 |
31-50 |
|
5 |
51-75 |
|
6 |
76-100 |
An inventory of benthic taxa was also compiled for each transect. Taxa were
identified in situ to the following
levels:
·
Scleractinian (hard) corals to species
wherever possible.
·
Soft corals, anemones and conspicuous macroalgae
recorded according to morphological features and to genus level where possible.
·
Other benthos (including sponges, zoanthids,
ascidians and bryozoans) recorded to genus level wherever possible or phylum
plus growth form.
Following the completion of
the survey at each transect, each taxon in the
inventory was ranked in terms of abundance in the community (see Table 7.6c). These broad categories rank taxa in terms of relative abundance of individuals, rather
than the contribution to benthic cover along each transect. The ranks are subjective assessments of
abundance, rather than quantitative counts of each taxon.
Table 7.6c Ordinal Ranks of Taxon Abundance
|
Rank |
Abundance |
|
0 |
Absent |
|
1 |
Rare (a) |
|
2 |
Uncommon |
|
3 |
Common |
|
4 |
Abundant |
|
5 |
Dominant |
|
Note: (a)
The
classification of “rare” abundance refers to low abundance (small quantity)
on the transect, rather than in terms of
distribution in |
|
A set of environmental site
descriptors were also recorded for each REA transect as follows:
(A)
The coral
communities were classified into one of three categories based on the amount of
three dimensional coral accretion:
(B)
The degree of exposure to prevailing wave energy was ranked from 1
- 4, where:
(C)
Sediment deposition on the reef substratum (particle sizes ranging
from very fine to moderately coarse) rated on a four point scale, from 0 – 3,
where:
During the REA survey, the field data were
recorded by an observer experienced in the underwater identification of sessile
benthic taxa (coral specialist), swimming along
identified sections of coastline on SCUBA from haphazardly-chosen starting
points. Due to the REA observers’
experience and familiarisation with the sublittoral
benthic communities of
All field data were checked upon
completion of each REA transect and a dive survey proforma
sheet completed at the end of the fieldwork day. Upon completion of the fieldwork photographs
were compiled for each transect.
Photographs for each REA transect were then reviewed and REA data
verified.
Once the transect photographs were
reviewed and REA data checked all data were input and stored in Excel spreadsheets. Two spreadsheets were used and data were
separated into:
·
site
(transect) information (Tier I and II data), depth and environmental
descriptors; and
·
species abundance data for each transect.
Species lists, species richness and mean
values for ecological and substratum types were compiled for the two depth
ranges surveyed within each of the two locations (natural and artificial
shorelines). The rank abundance values
were converted to a mid-value percentage cover.
Quantitative transect surveys were
conducted on the artificial seawalls next to the Project Site and the natural
rocky shore at Fat Tong Chau on 8 April 2008. The survey locations are presented in Figure 7.6b.
A
quantitative belt transect method was used for the intertidal survey. Three horizontal (belt) transects along the
shoreline were surveyed at each of the three shore heights: 2 m, 1.5 m and 1 m
above Chart Datum. On each transect, 10 quadrats (50 cm x 50 cm) were placed randomly to assess the
abundance and distribution of flora and fauna.
All organisms found in each quadrat were
identified and recorded to species level so that density per quadrat could be determined. Sessile animals such as algae, barnacles and
oysters in each quadrat were not counted but
estimated as percentage cover on the rock surface. All species of algae (encrusting, foliose and
filamentous) were also identified and recorded by estimating the percentage of
cover of the rock surface.
All REA surveys were conducted on 8 April
2008. Weather conditions were fine with
the dive locations sheltered from a moderate north-easterly wind, the sky was
overcast with sunny spells and the sea conditions calm with little
current. The underwater dive conditions
were typical for the nearshore waters of this region
of Hong Kong with waters highly turbid and of low light creating extremely low
underwater visibility conditions for all survey transects (lowest visibility
recorded was ~25 cm). The seabed of the
artificial seawall was composed of artificial boulders with very low coral
coverage (<1%) and only a few small colonies of Oulastrea crispata and Psammocora superficialis recorded. The seabed of the natural shoreline of Fat
Tong Chau was composed of mainly small to large sized boulders and soft
sediment (silt), and only a few small hard coral colonies
were observed (eg Montipora venosa, Psammocora superficialis, Turbinaria peltata, Cyphastrea serailia, and
Goniopora stutchburyi). The natural shoreline also had an extremely low coral cover (<1%).
A total of eight REA transects were
completed during the survey (T1 to T8).
Four transects were located at depths between -2 and -4 mCD while the remaining four were laid at depths of -4 to
-6 mCD. The
transects covered the natural shoreline to the south of the proposed biodiesel
plant (ie Fat Tong Chau) and the artificial seawall
at or adjacent to the proposed plant site (see Figure 7.6a)
The physical/abiotic
composition of the seabed substrata recorded for each transect
is represented in Tables C1 and C2 of Annex C. The natural
shoreline of Fat Tong Chau between -2 and -4 mCD was
composed of small to large sized boulders overlying bedrock in the intertidal
zone. A narrow boulder slope existed at
around 4 m depth and extended deeper.
Horizontal boulder surfaces at the lower depth range were heavily
silted. The artificial seawall was
composed of large introduced boulders/rocks and vertical and horizontal
surfaces were covered in a layer of silt.
At depths between -4 to -6 mCD, the seabed along the natural shoreline of Fat Tong
Chau was mainly composed of silt and mud with scattered small patches of shell
fragments. At the same depth range along
the artificial seawall of TKOIE, large boulders/rocks predominated and similar
to the shallow depths were covered in silt.
A total of six species of hard corals and
two species of gorgonians were recorded along the REA transects (see Tables C3 and C4 of Annex C) conducted
in the two depth ranges. Live coral
cover was less than 1% with isolated and scattered small, coral colonies
recorded for the shallow depths along the natural shoreline and at both depth
ranges of the artificial seawall. A
total of two hard coral species were recorded for both depths (ie -2 to -4 m and -4 to -6 mCD)
along the artificial seawall of TKOIE. Oulastrea crispata was
recorded for both depths while Psammocora superficialis was only recorded on deeper
transects. All these hard coral species
recorded on the artificial seawall are common and have a widespread
distribution throughout
A total of 14 hard coral colonies were
recorded along the transects. All corals encountered were not movable as
they were attached to either the natural nearshore or
artificial seawall rock. Most of these
immovable corals are small in size (<10cm in diameter) and were found to be
the common species that have been recorded throughout the coastal areas in the
eastern waters of Hong Kong with the exception of one species – Montipora venosa which
is categorised as uncommon (see Table
C6). Only one coral colony Psammocora superficialis
(<10cm in diameter) was recorded within the proposed jetty area.
In addition to the corals recorded the
benthic communities of the natural shoreline and artificial seawall comprised a
common suite of fouling organisms including (see Tables C3 and C4 in Annex C):
·
rock
oysters Saccostrea cucullata;
·
barnacles;
·
fan
worms,
·
common
sea cucumber Holothuria leucospilota;
·
bryozoans
Schizoporella errata;
·
bubble
anemone Entacmaea quadricolor (natural
shoreline only);
·
variety
of gastropods; and
·
sea urchins with the long-spined sea urchin Diadema setosum abundant
for both habitat types.
All fouling invertebrate species recorded
are common and widespread in
Representative photos of the subtidal marine fauna observed within the Study Area are
shown in Figures
7.7a to 7.7b and Figure C1 in Annex C.
General observations of fishes associated
with the natural and artificial seawall of the Study Area were noted during the
REA surveys and a list of species observed is presented in Table C7 of Annex C. A total of six fish species was recorded and
the abundance of fish was low. A suite
of common and widespread fish species were noted (for
Overall, the ecological value of the subtidal habitat within the Study Area is considered low.
The artificial seawall exhibited a low
diversity of species. Animals recorded
were mainly the rock oyster Saccostrea cucullata, periwinkles Echinolittorina radiata and E. trochoides,
and limpets Nipponacmea concinna and Patelloida pygmaea (see Table C8 of Annex C). The topshell Monodonta labio and chiton Acanthopleura japonica were also recorded in low
abundance. A few mobile juvenile
crustaceans were also observed at the mid intertidal zone during the survey on
the artificial seawall, though its identification remains unknown. Representative photos of the intertidal
habitats within the Study Area are shown in Figure 7.7c.
Dominant species of the natural intertidal
shoreline included the rock oyster Saccostrea cucullata, periwinkles Echinolittorina radiata and E. trochoides,
limpets Nipponacmea concinna and topshell Monodonta labio. Species found only in the natural shore
during the survey include snails Planaxis sulcatus, Chorostoma argyrostoma,
Lunella coronata, sea
anemone and numerous algal species.
These species are all common species on natural rocky shores of
Overall, results of the survey show that
all species were common and widespread, and no species of note were
recorded. Assemblage pattern appears to
be slightly different between the artificial seawalls and the natural
shore. Diversity of intertidal biota at
the Study Area was similar to those recorded from other shores in
In this section,
the ecological importance of marine habitats identified within the Study Area
is evaluated in accordance
with the criteria stipulated in Annex 8
of the EIAO-TM. The evaluation is
based upon the information presented in Section 7.7. The ecological importance of the subtidal and intertidal habitat types within the Study Area
are presented in Tables 7.8a and
7.8b.
Table 7.8a Ecological
Importance of the Subtidal Habitats within the Study
area
|
Criteria |
Natural
Shoreline |
Artificial
Shoreline |
|
Naturalness
|
Natural bedrock and boulder
substrate |
Introduced rock/boulder
seawall |
|
Size |
Short section of Fat Tong
Chau (~0.1 km) |
Long stretch of artificial
seawall (>1 km) |
|
Diversity |
Low for hard and soft
corals. A total of five hard coral species recorded |
Extremely low for hard and
soft corals. Two hard coral species recorded |
|
Rarity |
Low – majority of hard and
soft coral species commonly recorded throughout |
Low- all hard and soft
coral species commonly recorded throughout |
|
Re-creatability |
Hard bottom substrata may
be re-colonised by subtidal
organisms including corals |
Hard bottom substrata may
be re-colonised by subtidal
organisms including corals |
|
Fragmentation |
Low – typical fouling
community existing in turbid shallow waters of nearshore
|
Low – introduced substrate
and not representative of natural benthic assemblages. |
|
Ecological
Linkage |
Small section of natural
shoreline not functionally linked to any high value habitat in a significant
way. |
Artificial shoreline not
functionally linked to any high value habitat in a significant way |
|
Potential
Value |
Low. Marginal
representation of hard and soft corals with the habitat supporting sparse
coral cover. Highly turbid and high sedimentation rates indicate that the
area does not and will merit conservation measures. |
Low. Marginal representation of hard and soft corals with the habitat
supporting sparse coral cover though it is noted that hard corals have
settled on the introduced substrate. Highly turbid and high sedimentation
rates indicate that the area does not and will merit conservation measures. |
|
Nursery/Breeding Ground |
No significant records
identified during the literature review or field surveys. |
No significant records identified
during the literature review or field surveys |
|
Age |
Individual coral colonies
were typically <10 cm indicative of settlement within the last five years
or less. Individual colonies are scattered and no large hard coral colonies
or substantial biogenic accretion. |
Individual coral colonies
were typically <10 cm indicative of settlement within the last five years
or less. Individual colonies are scattered and no large hard coral colonies
or substantial biogenic accretion. |
|
Abundance/Richness
of Wildlife |
Extremely low with only a
few coral colonies collected. |
Extremely low with only a
few coral colonies collected. |
|
Overall Ecological Value |
Low |
Low |
Table 7.8b Ecological
Importance of the Intertidal Habitats within the Study Area
|
Criteria |
|
Artificial Seawall |
|
Naturalness |
Natural habitat (sheltered to semi-exposed rocky shores). |
Man-made habitat (slope
artificial seawall). |
|
Size |
Approximately 0.1 km of natural
rocky shores was recorded within the Study Area. No natural rocky shores were
found within the Project Site. |
Approximately 1.1 km of
artificial shoreline was recorded within the Study Area. |
|
Diversity |
Medium for intertidal marine flora and fauna. |
Low for intertidal marine flora and fauna. |
|
Rarity |
Nil. |
Nil. |
|
Re-creatability |
The habitat cannot be recreated. |
The habitat can be recreated. |
|
Fragmentation |
No. |
Not applicable. |
|
Ecological Linkage |
Not functionally linked to any
highly valued habitat in close proximity. |
Not functionally linked to any
highly valued habitat in close proximity. |
|
Potential Value |
Medium |
Low |
|
Nursery/Breeding
Ground |
Unknown. |
Unknown. |
|
Age |
Unknown |
Not applicable. |
|
Abundance/Richness
of Wildlife |
Medium |
Low |
|
Overall
Ecological Value |
Medium |
Low |
Potential impacts due to the construction
and operation of the Biodiesel Plant were assessed (following the guidelines
stipulated in Annex 16 of the EIAO-TM) and the impacts evaluated
(based on the criteria in EIAO-TM Annex 8).
Potential impacts to marine ecological
resources arising from the construction works will be associated mainly with
the construction of the jetty by piling.
These impacts may be divided into those due to:
·
Direct
disturbances to the habitat, ie habitat loss; and
·
Perturbations
to key water quality parameters, ie changes in water
quality.
Each of the above impacts is discussed in
detail below.
The jetty in the
form of a piled deck will be constructed for marine vessel berthing. Bore piles will be driven through the
existing rubble mound seawall. Direct loss of a small stretch of intertidal and
subtidal hard-substrata habitats associated with the
artificial seawall is, therefore, anticipated.
A total of about 60 piles, each with approximate diameter of 1 m and a
cross-sectional area of 0.8 m2, will be installed at the artificial
seawall of the Project Site (see Figures 3.2c and 7.6a). Piling works for jetty construction at the Project Site will thus result
in the loss of approximately 48 m2 of marine habitats within a 60 m
stretch of low ecological value intertidal and subtidal
artificial seawall area. Based on the
dive surveys, only one small coral colony Psammocora superficialis (<10cm in diameter) was
recorded within the Project Site boundary.
Intertidal and subtidal assemblages (ie rock oyster Saccostrea cucullata and bryozoans Schizoporella errata), as well as the small coral colony, within this area may
be lost through physical damage to organisms existing there. These assemblages are regarded as widespread
and common in other similar artificial intertidal and nearshore
areas of
No dredging of
marine sediment will be required for the construction of the jetty. As discussed in Section 6.5.1 (Water Quality Impact Assessment), it is expected
that marine piling will only result in limited disturbance to the sediments and
is unlikely to cause unacceptable impacts to the water quality (eg elevated suspended solids level) in Junk Bay. Consequently, adverse impacts on intertidal
and subtidal assemblages are not expected.
Likewise,
land-based construction activities at the proposed facility are not expected to
generate significant amount of contaminated construction site runoff and with
the implementation of good construction site practice as recommended in ProPECC PN 1/94 it is unlikely to result in
adverse water quality impacts.
Subsequent adverse impacts on marine ecological resources are thus not expected.
Potential impacts to marine ecological
resources arising from the operation of the proposed facility may include:
·
Changes
to hydrodynamic regime;
·
Presence
of artificial habitats provided by marine piles;
·
Changes
in water quality; and
·
Spillage of Raw Materials and Biodiesel Plants.
Each of the above is discussed in detail
below.
As discussed in Section 6.6.1, the presence of the
jetty and the associated piling structure is not expected to result in any
adverse impact to the hydrodynamic system and flow regime. No significant adverse impact on marine
ecological resources is, therefore, anticipated during the operation phase.
Direct, permanent loss of
a small stretch of artificial seawall is anticipated for the construction of
the jetty by piling. Although low
ecological value intertidal and subtidal
hard-substrata habitats and the associated marine assemblages at this stretch
of shoreline will be lost (see Section
7.9.1), since the piles will be installed at a depth of 4 m to 7.5 m, the presence of piles will provide approximately
750 to 1,400 m2 of artificial habitat for intertidal and subtidal organisms to colonise. The marine organisms recorded on the
artificial seawall have colonised this artificial substrate after the
completion of the seawall construction for the Tseung
Kwan O Industrial Estate. Moreover,
assemblages of marine organisms have been recorded on artificial habitats such
as wharf piles ([18]).
It is therefore expected that similar assemblages will settle on and recolonise the piles as environmental conditions of that
area would be similar to the existing conditions that have allowed the
settlement and growth of the marine organisms recorded.
All sewage and
wastewater generated during operational activities of the proposed facility
will be collected and treated at the on-site wastewater treatment plant prior
to off-site disposal via discharge to a foul sewer leading to the Tseung Kwan O Sewage Treatment Works. The effluent quality will comply with the
relevant discharge standards. Surface
runoff and site drainage will pass through on-site silt trap and oil
interceptors before discharge into the stormwater
drainage system of the Tseng Kwan O Industrial Estate. Overall, no adverse water quality impact due to effluent discharge is anticipated, and
subsequent adverse impacts on
marine ecological resources are thus not expected.
Accidental
spillage of biodiesel, PFAD and methanol may potentially occur during
loading/unloading operations at the jetty area.
With the implementation of loading and unloading control measures, the
possibility of accidental spillage will be low and volume of the material
released is anticipated to be small.
Both biodiesel and PFAD have low volatility and have density lower than
seawater. Upon spillage, biodiesel will
form a thin slick on the water surface while PFAD will float on water in solid
form so that it is unlikely to disperse and should be relatively easy to clean
up. In addition, both biodiesel and PFAD
are non-toxic and biodegradable, therefore adverse impacts on marine ecological
resources are expected to be minimal upon spillage.
Methanol, however,
is highly volatile and is completely miscible with seawater. It has a relatively short half-life in
aqueous environments (< 7 days) and is biodegradable; therefore it is
unlikely to accumulate or persist in the marine environment upon spillage ([19]). Research has also shown that methanol is
essentially non-toxic to marine organisms ([20]). As methanol would rapidly dissipate into the
environment, and within fairly short distances from the spill it would reach
levels where biodegradation would rapidly occur, it is reasonable to expect
that the dilution and dispersion capacity of the surrounding coastal waters is
sufficient to buffer the adverse effects, if any, of the spill. No significant impacts on marine ecological
resources are thus expected.
Based upon the information presented
above, the significance of the marine ecological impacts associated with the
construction and operation of the proposed facility have been evaluated in
accordance with Table 1 of Annex 8 of the EIAO-TM, and are summarised in Table
7.9a.
Table
7.9a Overall Impact Evaluation for
Intertidal and Subtidal Artificial Hard Substrata Habitat
|
Evaluation
Criteria |
Intertidal and Subtidal
Artificial Hard Substrata Habitat |
|
Habitat
quality |
Low |
|
Species |
The potential exists for direct and indirect impacts to
the marine faunal species, particular sessile species. One coral colony Psammocora superficialis (<10cm in diameter)
was recorded within the proposed jetty area during the dive survey. |
|
Size/Abundance |
Permanent area loss is approximately 48 m2. |
|
Duration |
The impact will persist during the construction and
operation phases. |
|
Reversibility |
Impacts to assemblages inhabiting the seawall within
the direct footprint of the proposed jetty and piling work area are expected
to be permanent. Recolonisation on
piles is expected to occur. |
|
Magnitude |
The scale of the habitat loss is small in the context
of the surrounding similar habitats. |
|
Overall Impact Conclusion |
Low |
Overall, the impact assessment indicates that
no unacceptable adverse impacts to marine ecology are expected to occur. Loss of intertidal and subtidal
assemblages as a result of piling is expected to be compensated through the
provision of artificial habitats from piles that provide adequate surfaces for
colonisation.
Several existing and planned projects have been identified in the Tseung Kwan O area which are mainly roads and infrastructure
works (see Table 7.10a). Based on the tentative project development programme,
the construction of the biodiesel plant will be completed by early 2010. The concurrent projects during the
construction of the biodiesel plant are the TKO Further Development project,
the SENT Landfill Operation and TKO Area 137 Fill Bank. The latter two projects are land-based and
will be located at least 700 m away from the biodiesel plant and so no
cumulative impacts are expected. For the
TKO Further Development project, given the large separation distance (>2,000
m) from the biodiesel plant (which is small in scale), it is also expected that no
cumulative impacts on the nearshore marine ecological
resources will occur.
Table 7.10a Planned Projects in TKO
|
Planned
Projects |
Distance
from Biodiesel Plant (m) |
Planned
Construction Date |
|
Cross Bay Link |
> 600 |
2013 – 2016 |
|
TKO - Lam Tin Tunnel |
> 1,800 |
2012 – 2016 |
|
TKO Further Development –
infrastructure works at Town Centre South and Tiu Ken Leng |
> 2,000 |
Mid 2009 – 2011 |
|
SENT Landfill
Operation |
700m |
Till end of 2012 |
|
SENT Landfill Extension |
> 1,000 |
2011 - 2018 |
|
TKO Area 137
Fill Bank |
>1,000 |
Till 2013 |
·
Avoidance: Potential
impacts should be avoided to the maximum extent practicable by adopting
suitable alternatives;
·
Minimisation: Unavoidable
impacts should be minimised by taking appropriate and practicable measures such
as constraints on the intensity of works operations or timing of works
operations; and
·
Compensation: The loss of
important species and habitats may be provided for elsewhere as
compensation. Enhancement and other
conservation measures should always be considered whenever possible.
Proposed mitigation measures for
minimising impacts to marine ecological resources are summarised below.
Once available, the location of the piles
will be reviewed to determine the possibility of preventing direct loss of hard
coral colony and other marine organisms caused by the piling footprint. Therefore, no unacceptable environmental
impact is anticipated.
Mitigation measures for minimising water
quality impacts are presented in detail in Section
6.7.1. These measures will be
properly implemented and good construction practices will be adopted to
minimise potential adverse impacts to marine ecological resources.
Any spillages will
be intercepted by the collection drain and conveyed into the on-site wastewater
treatment plant, and an Emergency Response Plan will be in place and implemented should spillages occur to minimise potential impacts on the
marine environment.
Specific measures for spill containment
are presented in Section 6.7.2.
There
will be a permanent loss of approximately 48 m2 of intertidal and subtidal habitats at the artificial seawall due to marine
piling for jetty construction. Given the
fact that these habitats are of low ecological value and recolonisation
of marine organisms on the piles is expected, the residual impacts are
considered to be low.
With
effective implementation of the proposed mitigation measures for the construction and operational
phases of the biodiesel plant, no further adverse residual impact
on marine ecological resources is expected.
The Impact Assessment has evaluated that
there would be no unacceptable marine ecological impacts within the Study
Area. As a result, it is considered that
environmental monitoring is not required.
Nevertheless, regular site inspection is recommended during construction
to ensure that the recommended mitigation measures on water quality are
properly implemented such that secondary adverse impacts on marine ecological
resources can be avoided and minimised.
Findings of this
Impact Assessment suggest that the marine habitats within the Study Area are of
low to medium ecological value, and potential adverse impacts are only
anticipated at the low ecological value intertidal and subtidal
habitats and associated assemblages at the seawall in the immediate vicinity of
the Project Site.
Permanent loss of a small stretch of
marine habitats at the artificial seawall is expected due to marine piling for
jetty construction. Pile surfaces can,
however, serve as artificial habitats for settlement and recolonisation
of marine assemblages. Residual
impacts are expected to be low.
Other potential impacts to marine
ecological resources, which may be caused by changes in water quality and
hydrodynamic regime, and accidental spillage of raw materials and biodiesel
during the construction and operation phases of the proposed facility, are
likely to be negligible and minimal provided that the recommended mitigation
measures and good site practices are implemented.
No environmental monitoring is thus
considered necessary during the construction and operation phases of the
Project. Regular site inspections
are recommended during construction.