7 MARINE ECOLOGY
7.1.1.1 This section of the EIA Report presents details of the assessment of the construction and operation of the Trunk Road T2 project on marine ecological resources within the study area and describes the sensitive receivers present, potential impacts from the project and recommends suitable mitigation measures. The ecological impact assessment of the proposed project should follow the criteria and guidelines for evaluating and assessing ecological impacts as stated in Annexes 8 and 16 of the Technical Memorandum on Environmental Impact Assessment Process (TM-EIA).
7.1.1.2 In order to achieve the aforementioned measures, the major objectives of the assessment are broadly as follows:
·
to review the
findings of relevant studies and collate all the best available information
regarding the ecological characters of the study area;
·
to evaluate the
information collected and identify any information gap relating to the
assessment of potential ecological impacts to the aquatic environment;
·
to establish the
general ecological profile and describe the characteristics of each habitat
found based on literature review;
·
to assess the
ecological impacts of the project according to Table 1 of the TM-EIAO, based
upon an impact significance grading on scale of insignificant, minor, moderate
and high;
·
to develop
feasible and effective mitigation measures for significant impacts to minimise pollution, environmental disturbance and nuisance
during construction and operation of the projects;
·
to investigate the
feasibility, effectiveness and implications of the proposed measures to
mitigate these impacts and definition of the scope, type, location,
implementation arrangement, resources requirement, subsequent management and
maintenance of such measures;
·
to identify,
predict and evaluate the residual environmental impacts and the cumulative
effects expected to arise during the construction and operation phase of the
project;
·
to identify,
assess and specify methods, measures and standards to mitigate these residual
environmental impacts and cumulative effects and reduce them to acceptable
levels; and
·
to review the need for and recommendation on any
ecological monitoring programme required.
7.1.1.3 For the ecological impact assessment, the ecological baseline in the study area has been determined by reviewing literatures. Being in the region of recent and proposed developments, including the Central Kowloon Route (CKR), Tseung Kwan O - Lam Tin Tunnel (TKO-LTT), Kai Tak Development (KTD), Kai Tak Cruise Terminal (CTD), Tolo Harbour Effluent Export Scheme (THEES), etc., the marine ecological resources of the study area are well studied and characterised. The literature review provides relatively recent site specific surveys and the baseline information is extensive and of particular relevance to the Trunk Road T2 ecological Study Area.
7.1.1.4
In terms of the terrestrial
environment, the terrestrial physical environment of the KTD assessment area
includes mostly the former
7.1.1.5 The Cho Kwo Ling end of the alignment will be in tunnel as it interfaces with the Tseung Kwan O Lam Tin Tunnel project (TKO-LTT) but has a portal and ventilation building at the LTT interchange. This area is the site of a former quarry and will be developed by the TKO-LTT project.
7.1.1.6 As the Trunk Road T2 project will be built on largely developed or disturbed land, terrestrial ecological impacts are not expected and have not been considered further.
7.1.1.7 Since all construction works would take place on existing developed land and no marine works that would disturb the seabed are involved, the ecological impacts associated with this Trunk Road T2 EIA Study are expected to be minimal. Given that the existing baseline data is comprehensive and highly relevant, further surveys of Trunk Road T2 Project area are not considered as being required.
7.2 Environmental Legislation, Standards and Guidelines
7.2.1.1 A number of international and local regulations, legislation and guidelines provide the framework for the protection of species and habitats of ecological importance and these include:
·
Technical
Memorandum for the Environmental Impact Assessment Ordinance (TM - EIAO). Annexes 8 and 16 of the Technical
Memorandum EIAO (Cap. 499) 1997 which sets out general criteria for evaluating
the ecological importance of and hence the significance of potential ecological
impacts and guidance for ecological assessment, respectively;
·
Marine Parks Ordinance (Cap. 476) which applies to the marine park at Sha Chau and Lung Kwu Chau and limits certain
activities in this area;
·
Wild Animals
Protection Ordinance (Cap. 170)
which protects all birds and most mammals;
·
Protection of
Endangered Species of Animals and Plants Ordinance (Cap. 586) which controls the trade in threatened and
endangered species and local possession of them. Cap. 586 replaced the “Animals
and Plants (Protection of Endangered Species) Ordinance (Cap. 187)” on 1
December 2006. The Ordinance is the local legislation that implement CITES;
·
Town Planning
Ordinance (Cap. 131) which
provides for the designation of coastal protection areas, Sites of Special
Scientific Interest (SSSIs), Conservation Area, Country Park, Green Belt or
other specified uses that promote conservation or protection of the
environment;
·
·
The World
Conservation Union IUCN (version
2009.1) maintains, through its Species Survival
Commission, a “Redlist” of globally threatened
species of wild plants and animals (see http//www.iucnredlist.org). The Redlist is
considered the authoritative publication to classify species as critically
endangered, endangered, vulnerable, or lower-risk;
·
United
Nations Convention on Biodiversity
(1992) which requires signatories to make active efforts to protect and manage
their biodiversity resources. Hong Kong
Government has stated that it will be 'committed to meeting the environmental
objectives' of the Convention (PELB 1996); and
·
Convention on
the International Trade in Endangered Species of Flora and Fauna (CITES). The import, export and possession of the
listed species are regulated by Cap 586.
7.3 Key Ecological Sensitive Receivers
7.3.1.1
In accordance with the EIA
Study Brief, the marine ecology assessment area would cover the entire Eastern Buffer Water Control Zone (WCZ), the Victoria Harbour WCZ and the Western Buffer WCZ and other area
likely to be impacted by the Project (Figure 6.1).
7.3.1.2 There are, also, records of the marine mammals Chinese White Dolphin (Sousa chinensis) in the Western Buffer WCZ and the Finless Porpoise (Neophocaena phocaenoides) in the Eastern Buffer WCZ, although even the wider assessment area is at the extremes of the distribution of these two species. In the latest 2011-12 marine mammal monitoring (AFCD, 2012), none of the Finless Porpoise were recorded in the Eastern Buffer WCZ, while Chinese White Dolphin was recorded near Ma Wan in the Western Buffer WCZ (Hung, 2012), which is over 8km from the project site.
7.3.1.3 As discussed in the Water Quality Impact Assessment in Section 6, potential adverse impacts are expected to be localised as a result of the adoption of the Tunnel Boring Machine (TBM) method of the subsea tunnel construction which will avoid all direct impacts to the marine environmental and seabed. Impacts are, therefore, not expected to occur at any far-field sensitive receiver such as the Chinese White Dolphin in the Western Eastern Buffer WCZ. Therefore, the study area for the Trunk Road T2 marine ecology impact assessment has been focused on the eastern part of Victoria Harbour in the vicinity of the project boundary (Figure 6.2). The species of conservation interest identified in the marine study area comprise only corals (Figure 7.1a-d).
7.4.1.1 The purpose of the literature review is to identify existing information on the habitats and species present within the study area. Various reports and studies have been consulted to extract relevant data on the flora, fauna and habitats present in the study area. Relevant books and scientific papers have, also, been consulted and these have been cited where appropriate, although the most recent reports have been generally relied upon to provide contemporary information of the ecological characteristics of the study area.
7.4.1.2 Relevant scientific publications and EIA reports have been reviewed. The EIA and Environmental Monitoring and Audit (EM&A) studies reviewed include:
·
Comprehensive Feasibility Study
for the Revised Scheme of South
· Agreement No. CE 42/2001, Environmental and Engineering Feasibility Assessment Studies in Relation to the Way Forward of the Harbour Area Treatment Scheme – Water Quality, Ecological and Fisheries Impact Assessment (HATS EEFS Report);
· Agreement No. CE 35/2006 (CE). Kai Tak Development Engineering Study cum Design and Construction of Advance Works – Investigation, Design and Construction. Kai Tak Development Environmental Impact Assessment Report (KTD EIA) (EIAO Register No. AEIAR-130/2009);
· Agreement No. CE 35/2006 (CE). Kai Tak Development Engineering Study cum Design and Construction of Advance Works – Investigation, Design and Construction. Dredging Works for Proposed Cruise Terminal at Kai Tak EIA Report (CTD EIA) (EIAO Register No. AEIAR-115/2007);
· Sha Tin to Central Link EIA Study for Tai Wan to Hung Hom Station (SCL EIA) EIAO Register No. AEIAR- 167/2012);
· EIA study for the installation of Submarine Gas Pipelines and Associated Facilities from To Kwa Wan to North Point for Former Kai Tak Airport Development EIAO Register No. AEIAR- 153/201);
· Agreement No. CE 42/2008 (CE). EIA study of Tseung Kwan O–Lam Tin Tunnel (TKO–LLT) (It should be noted that, in this EIA report, all details in relation to the proposed TKO–LLT project are tentative only as it is subject to obtaining government and statutory approvals. The assessments related to the TKO–LLT project are based upon the best available information at the time of the submission of this EIA report. TKO–LLT is under a separate EIA study and subject to the study requirements of a separate EIA study brief under the statutory processes of the EIAO); and
·
Agreement No. CE 43/2010 (HY)
7.4.1.3 Existing literature, also, provides a good baseline for species assessments. Other relevant literature reviewed includes:
· Porcupine! (Newsletter of the Department of Ecology and Biodiversity, Hong Kong University); and
· Hong Kong Biodiversity (AFCD Newsletter).
7.4.2.1 The EIA Study Brief broadly defines the marine ecology assessment area for this Project to include the Victoria Harbour Water Control Zone (WCZ), the Eastern Buffer WCZ and the Western Buffer WCZ which is the same as the water quality impact assessment, or the area likely to be impacted by the Project. However, as described in Section 3, the adoption of the TBM tunnel method means that there will be no direct impacts to the marine environment from the Trunk Road T2 construction or operation. However, due to construction dust deposition, site run-off and accidental spillage, potential indirect off-site impacts to the waters around the work site, that is, KTAC, KTTS and the Kwun Tong-Cha Kwo Ling waterfront, all within the Victoria Harbour, could occur and potentially affect marine ecological resources.
7.4.2.2 It is anticipated that these impacts could be controlled with good site practices in place during the construction phase. As such, the marine ecological assessment for this Trunk Road T2 project has focussed on the areas within the Kai Tak Approach Channel (KTAC), the Kwun Tong Typhoon Shelter (KTTS) and the Kwun Tong - Cha Kwo Ling waterfront, in the eastern Victoria Harbour WCZ. These areas are collectively defined as the study area for the marine ecology assessment which is same as that for water quality assessment (Figure 6.2).
7.4.2.3 There are no important ecological sensitive receivers, such as Marine Parks, Marine Reserves or other areas of conservation importance in the study area for marine ecology. However, several broad marine habitats can be found in the study area including:
·
Benthic habitats on soft bottom substratum at
·
Intertidal habitats on artificial seawalls along the former airport
runway and along the coastlines of TKWTS, KTTS and KTAC; and
·
Subtidal habitats at
7.4.2.4
There
have been some recent studies on the habitats found in
the study area and marine ecology surveys conducted for KTD EIA and THEES are
of particular relevance. The literature
review reveals that there is comprehensive existing baseline information and
recent site specific surveys of the study area.
As mentioned above, no marine work are proposed for the Trunk Road T2
project and, therefore, only indirect impacts from land-based construction
works would be likely induced. Thus, it is considered that the evaluation of
the marine ecological impacts can be based on the existing information from
literature review and no further marine ecological surveys are considered
necessary for the purpose of this EIA study.
Corals
and Hard Substrata Benthos
7.4.2.5
Certain types of corals such as
blue coral (Heliopora coerulea),
organ pipe corals (family Tubiporidae), Black corals
(order Antipatharia), Stony coral (order Scleractinia), fire corals (family Milleporidae)
and lace corals (family Stylasteridae) are protected
in
7.4.2.6
The
richest coral communities are found in the eastern part of Hong Kong where the
waters are free from the influence of estuarine water from the
7.4.2.7
The Rapid Ecological Assessment
(REA) dive surveys in the TKWTS, carried out under the SCL EIA study for Tai
Wai to Hung Hom Station (ARUP, 2011), revealed that a
total of 17 colonies of only one species of hard coral, Oulastrea crispata (Family Faviidae) was
present along the artificial shores. The size of the colonies ranged from 4 to
24cm2. Along the transects, the recorded colonies were generally of
normal status and showed low levels of sedimentation (2 to 20%), bleaching (0%)
and mortality (0%). All colonies were
associated with large boulders of diameters of about 50cm to 150cm.
7.4.2.8 Under the EIA study for the installation of Submarine Gas Pipelines and Associated Facilities from To Kwa Wan to North Point for Former Kai Tak Airport Development (Mott MacDonald, 2010), sub-tidal dive surveys were conducted at the breakwater at To Kwa Wan. The hard coral Oulastrea crispata was commonly found attached to the artificial boulder breakwater but in low densities and coverage. The corals were recorded to be generally in good condition with colony sizes ranging from about 1cm2 to over 150cm2.
7.4.2.9
The results of the dive survey
for KTD EIA (Maunsell, 2008) indicated only limited
marine life to be present during the dive surveys (both spot-dive and
REA). No coral communities were
recorded at Kai Tak Approach Channel (KTAC) and Kwun Tong Typhoon Shelter (KTTS) while only scarce coverage
(1-5%) of single hard coral species (Oulastrea crispata) was recorded along the former
7.4.2.10 The dive surveys in the central Victoria Harbour carried out under Wanchai Development Phase II (WDII) and Central-Wanchai Bypass (CWB) EIA (Maunsell, 2007b), also, reported sparse coverage of less than 1% of the same hard coral species (Oulastrea crispata) and one octocoral species (gorgonian Echinomuricea sp.) in the central Harbour area, approximately 4.7 km and 3.5 km from the Trunk Road T2 project boundary, respectively. All the colonies found were in fair health but small in size with hard corals of 3 - 8cm in diameter. Neither soft coral nor black coral was identified during the surveys for the WDII and CWB EIAs.
7.4.2.11 Dive surveys for HATS EEFS study (CDM, 2004) indicated that the shallow waters of Joss House Bay and north-west Tung Lung Chau, about 8 km from the Trunk Road T2 study area, supported a moderate diversity of hard coral communities but with low coverage. However, the same study showed that no hard corals or soft corals were observed in the North Point areas.
7.4.2.12
Based on the literature review,
no coral was found in the KTTS or KTAC, although the
presence of a protected hard coral (Oulastrea crispata) was found in the vicinity of study area along the former
7.4.2.13
Artificial seawall virtually
covers the entire shoreline of
7.4.2.14
The literature has indicated that
fauna present on the seawalls and rockfills in the
other harbour areas were largely restricted to encrusting sessile organisms,
such as bivalves, molluscs and barnacles (Morton and Morton, 1983; Lee, 1985;
Lee and Morton, 1985). Fauna reported to
be commonly encountered included molluscs, such as the common neogastropod Thais clavigera and the pollution-tolerant bivalve Perna viridis, as
well as encrusting crustaceans such as barnacles (Balanus spp., Tetraclita squamosa and Capitulum mitella) and the ubiquitous mobile
isopod (Ligia exotica) (Morton and Morton, 1983; Lee,
1985; Lee and Morton, 1985). Floral
species were mostly restricted to algae that are either organic or nutrient
enrichment indicators such as Ulva spp. and Cladophora (Morton and Morton,
1983; Ho, 1987; Moore, 1990).
7.4.2.15
A review of an investigation
study on Laying of Western Cross Harbour Main and Associated Land Mains from
West Kowloon to Sai Ying Pun (Mott Connell Ltd., 2007) revealed that intertidal species
along
7.4.2.16 Intertidal fauna surveys were also conducted on artificial seawalls and rockfills in the central harbour area in Wanchai as part of the WDII and CWB EIA (Maunsell, 2007b). The study indicated that artificial seawalls along the coastline were found to be generally densely inhabited by a few species of sessile encrusting fauna, including chiton (Acanthopleura japonica), barnacle (Tetraclita squamosa) and bivalve (Saccostrea cucullata). Mobile species found on the artificial seawalls were the common Sea Slater (Ligia exotica) and the Topshell (Monodonta labio). Encrusting algae (Pseudulvella applanata and Hildenbrandia sp.) were recorded on the surface of artificial vertical seawalls. However, there were no erect algaes or higher flowering plants found during the survey. All of the fauna and flora were common local intertidal species of low conservation importance. Compared with the homogenous nature of the concrete seawalls, a more diverse and abundant intertidal community can be found on artificial rockfills.
7.4.2.17
Although fouling organisms are regarded as common on
artificial seawalls (Morton & Morton, 1983), there was no intertidal fauna
found on vertical seawalls during the previous SEKDCFS EIA Study (Arup, 2001).
Nonetheless, intertidal fauna of low ecological value such as isopods and grapsid crabs were recorded on the rubble-mound seawalls.
7.4.2.18
Inter-tidal surveys were also
conducted on the vertical seawall and sloping boulder-mounted seawall of the
Kai Tak runway along the coast of
7.4.2.19
Results from KTD EIA study showed that no intertidal fauna was
recorded along the KTAC but only the algae Hincksia
mitchelliae was recorded (Maunsell,
2008). The habitat quality was considered as very poor due to the poor water
quality and has very limited ecological value.
Compared to other relevant findings within the
7.4.2.20
More
recent results based
upon a walkover survey for the SCL EIA
study for Tai Wai to Hung Hom Station (ARUP, 2011) indicated that intertidal fauna species recorded in the Kai Tak area,
near the northern tip of former Airport runway, are common and widespread and
typical of those found in the
7.4.2.21
In general, the artificial
intertidal habitats within the Kai Tak area were very typical of
Soft
Bottom Benthic Macro-Infauna
7.4.2.22
Numerous
studies on benthic fauna assemblages have been conducted within the
7.4.2.23
Thompson and Shin (1983)
reported that benthic assemblages in the
7.4.2.24
Another
benthic survey was conducted of the seabed in the
7.4.2.25
The results of a field survey for the SSDS EIA
Study (Binhai, 2000) indicated a very low species diversity
and evenness
for benthic assemblages in the
7.4.2.26
A
recent territory wide benthic study in Hong Kong (CityU,
2002) revealed that a coarser sediment benthic group was found in the eastern
Victoria Harbour, as compared to eastern and southern waters, with lower
species diversity and evenness resulting.
This study showed that the benthic communities in the Victoria Harbour
comprised of mainly polychaete (Cirratulus sp., Schistomeringo rudolphi, Dodecaceria sp., Naineris sp., Sigambra hanaoka and Prionospio sp.), oligochaete (Thalassodrilides gurwitchi), bivalve (Ruditapes philippinarum) and crustacean (amphipod Cheiriphotis megacheles) (CityU, 2002). It
indicated a distinct benthic composition which is characterised by species
strongly adaptable to eutrophic environment.
7.4.2.27
Other recent surveys for the HATS EEFS Study (CDM, 2004) on benthic
assemblages in the
7.4.2.28
The SEKDCFS EIA Study (Arup, 2001) has
undertaken benthos samplings in the TKWTS, KTTS and KTAC. Only two species of benthic fauna were found
in the TKWTS, including the dominant (>99% of all collected specimens) polychaete Capitella capitata and a juvenile ocypodid
crab Macrophthalmus
sp. Low species diversity and evenness
were recorded and no living organism was collected from the sampling locations at
the KTAC and KTTS, revealing the very poor habitat quality in these areas (Arup, 2001).
7.4.2.29
Another field survey of
soft bottom benthic organisms from the seabed in the Victoria Harbour and KTTS,
undertaken for the THEES
Study (Meinhardt, 2008), indicated that the benthic assemblage was dominated by
annelids during both the wet and dry seasons.
The spionid polychaete
Prionospio cirrifera and
cirratulid Tharyx sp. were the most commonly found dominant species and
dominated in the sediment grab samples collected from over half of the sampling
stations. The general dominance of these
species in the majority of the stations suggested that the benthic assemblages
of the wider study area were polluted or disturbed to a certain degree. It was, also, noted that a few individuals
of the locally rare amphioxus Branchiostoma belcheri were recorded during both the wet and dry
seasons. Branchiostoma belcheri is a
Grade II Stated protected species in
7.4.2.30
A benthos survey for the
KTD EIA study was conducted at the
7.4.2.31
The
soft-bottom substrate is the dominant sub-tidal marine habitat in the Trunk
Road T2 study area. The benthic macro-infauna is
usually sessile or has limited mobility, except at the platonic larvae
stage. Given that the available data is
extensive and site specific and the soft-bottom substrate would not be directly
affected by the Trunk Road T2 construction works for the subsea tunnel, the evaluation of impacts to benthic macro-infauna could be based on the available information from literature review
and no further marine ecological surveys are considered necessary
for the purpose of this EIA study.
7.5 Evaluation of Ecological Importance
7.5.1
Species of Conservation Interest
7.5.1.1
Annex 8 of the TM-EIAO specifies three criteria by which a species’
conservation significance may be measured: protection status (local, Chinese or
international), with legally protected species afforded higher conservation
value; geographical distribution, with higher conservation value afforded to
species with more restricted geographical ranges; and rarity, with higher
conservation value afforded to species which are internationally rare than to
species which are only regionally or locally rare.
7.5.1.2
Thus, a species of ‘Local Concern’ may not be particularly threatened
globally or regionally, but is rare or restricted in
7.5.1.3 The species of conservation interest in the study area are limited to corals, with no other flora or faunal species of conservation interest having been identified.
Table 7.1 Species of Conservation Interest
Recorded in the Study Area
|
Species |
Level of Conservation
Interest(1) |
Location Recorded |
Rarity / HK Status |
|
Coral Community |
|||
|
Hard Coral Oulastrea crispata |
Wild
Animals Protection Ordinance |
Along the breakwater of TKWTS and the
former |
Locally common coral O.
crispata mainly inhabit subtidal turbid
water, attached to wave washed rock; and the abundance is generally not high
within its distribution range (Veron 2000). |
Remarks: (1) PRC= Potential Regional Concern;
RC=Regional Concern; LC = Local Concern, as of Fellowes et al. (2002). Those in
parenthesis indicate that the assessment is on the basis of restrictedness in
breeding and/or roosting rather than general occurrence.
7.5.2.1 Based on the literature review on the characteristic and species recorded in the marine habitats found within the study area and the criteria set in Annex 8 of TM-EIAO, ecological values of these habitats are listed in Table 7.2 below.
Table 7.2 Ecological Evaluation of
Marine Habitats Present Within the Study Area
|
Criteria |
Soft
Benthic |
Hard Sub-tidal |
Intertidal |
|
Naturalness |
Subject
to extensive anthropogenic disturbance |
Highly disturbed by marine traffic, subject
to extensive water pollution |
Artificial seawall |
|
Size |
Large |
The study site is connected to adjacent
benthic habitat, resulting in a relatively large habitat size. |
Large |
|
Diversity |
Low,
mainly dominated by pollution-tolerant fauna |
Low,
species confined to those resistant to polluted water. The species composition
was consistent with previous studies in |
Low, mainly composed of few intertidal fauna |
|
Rarity |
Species recorded
in Kai Tak area are generally common and widespread in |
No
species of conservation interest was recorded except common
hard coral species Oulastrea crispata is present on the seawall along the Kai Tak Runway at To Kwa
Wan side and has been recorded elsewhere in |
No rare species found |
|
Re-creatability |
High |
High |
Very high |
|
Fragmentation |
Fragmented
by the former airport runway |
Highly connected to adjacent marine benthic
habitat although fragmentation due to disturbance possible |
Not fragmented |
|
Ecological linkage |
Not functionally
linked to any highly valued habitat in close proximity |
Functionally
linked to overlying water column and adjacent benthic habitats |
Not
functionally linked to any highly valued habitat in close proximity |
|
Potential Value |
Very
low |
Very low |
Very low |
|
Nursery/ breeding ground |
No significant record |
No significant record |
No significant record |
|
Age |
Not known. |
Not known |
Not known |
|
Abundance/ richness of wildlife |
Low for
abundance and species richness |
Low for
abundance and species richness |
Low for abundance and species richness |
|
Ecological
Value |
Very Low |
Low |
Very
Low |
7.5.2.2
The habitats present within the study area have been
ranked according to their overall ecological value and range between very low to
low-moderate as summarised in Table 7.3 below.
Table 7.3 Summary of Marine Habitats and their Ecological
Value Within the Study Area
|
Marine
Habitat |
Ecological
Value |
|
Soft Benthic |
Very Low |
|
Hard Subtidal |
Low |
|
Intertidal (Artificial) |
Very Low |
7.6 Ecological Impact Assessment Methodology
7.6.1.1
The
objective of the ecological assessment is to predict the direct and indirect,
primary and secondary,
on-site and off-site impacts of the project on the marine environmental and ecological
resources and
habitats. The significance of any
predicted ecological impacts have been evaluated based on
the criteria stipulated in Table 1, Annex 8 of the TM-EIAO using the following
criteria:
· habitat quality;
· species affected;
· size/abundance of habitats affected;
· duration of impacts;
· reversibility of impacts; and
· magnitude of environmental changes.
7.6.1.2
Impacts
are ranked as
“minor”, “moderate” or “severe”, although in a few cases, “insignificant” (less
than “minor”) or “extremely severe” may also be given. The ranking of a given impact will vary based
on the criteria listed above. For
example, an impact might be ranked as “minor” if it affected only common
species and habitats, or if it affected only small numbers of individuals or
small areas, whereas it might be ranked as “severe” if it affected rare species
or habitats, large numbers of individuals or large
areas. The major factors giving rise to
a ranking of “moderate” or “severe” are spelled out in the text as far as
possible. As noted in Annex 16 of the
TM-EIAO, a degree of professional judgment is involved in the evaluation of
impacts.
7.6.1.3
If
ecological impacts are found to be significant, that is, moderate to severe,
mitigation needs to be carried out in accordance with the TM-EIAO. Mitigation measures are not required for
insignificant impacts although precautionary and /or enhancement measures may
be recommended if desirable. The policy
for mitigating significant impacts on habitats and wildlife is to seek to
achieve impact avoidance, impact minimisation and impact compensation in that
order of priority. Impact avoidance
typically consists of modifications to the project design, but may in extreme
cases require abandonment of the project (the “no-go” alternative). Impact minimisation
includes any means of reducing the scope or severity of a given impact, e.g.,
through timing of construction works, modification in design, or ecological
restoration of disturbed areas following the completion of works. Impact compensation assumes that an irreversible
impact will occur upon a given habitat or species and attempts to compensate
for it elsewhere, for example, by enhancement or creation of suitable
habitat. Compensation may take place
on-site or off-site.
7.7 Construction Phase Impact Assessment
7.7.1.2 Potential indirect impacts are mostly associated with the construction site run-off. Details of the construction works for the TM-CLKL are provided in Section 3 and, also, in the Water Quality chapter, Section 6.
7.7.1.3
The key potential indirect impacts of these works could include:
· Temporary loss of inter-tidal habitat resulting from operation of the
barging point;
· Increased disturbance to marine life due to deterioration of water
quality from construction site run-off; and
· Increased disturbance from construction phase marine vessels to marine
life.
Direct Impact:
Permanent Habitat Loss
7.7.1.4 The construction works will involve site clearance, site preparation, earthworks, tunnelling using the Tunnel Boring Machine (TBM) method, excavation of launching/receiving shaft and other general construction activities. All are land-based works and no dredging, reclamation, filling or other marine works that would disturb the seabed will be involved. Therefore, no direct permanent loss of marine habitat during the construction phase is expected.
Direct
Impact: Temporary Habitat Loss
7.7.1.5 The barging point is proposed to be located at the former Government Logistics Department Kowloon Bay Cargo Handling Area. No dredging for the installation of barging point is required and as such, loss of sub-tidal and benthic habitat would not be anticipated.
7.7.1.6 The proposed temporary barging point has a vertical seawall face and has been used for berthing and loading/unloading of marine vessels by various Government Departments. No additional temporary facilities would be needed to be constructed in the water as the unloading ramp would cantilever out from supports located on the existing seawall.
7.7.1.7
However, the barging point operations at the South Apron would result in
a temporary loss of inter-tidal habitat of approximately 100m. Approximately 100m of the inter-tidal habitat
along the South Apron would be directly affected during construction phase due
to the operation of the proposed barging point.
The artificial intertidal habitats within the Kai Tak area are very
typical of
7.7.1.8 The ecological value of the intertidal habitats to be temporarily lost is generally considered to be very low, does not containing any species of conservation interest and the duration of any impact is temporary and reversible in nature. Therefore, it is considered that any impacts would be of insignificant significance.
Indirect Impact:
Disturbance to Habitats Associated with Deterioration of Water Quality
7.7.1.9
In the
works area in close proximity to the marine waters, incorrect storage of
construction material and poor management of construction site run-off may cause
deterioration of marine water quality through run-off and an increase in local
suspended solids.
7.7.1.10
Site run-off may lead to
temporary water quality issues and an increase in local suspended solids for a
short period of time. It is anticipated that these impacts could be controlled
under ProPECC PN 1/94 Construction Site Drainage and,
thus, they would be temporary and negligible with good site practices in place
during the construction phase. As the ecological value of the surrounding marine habitats, that is, inter-tidal, hard sub-tidal and benthic
habitats, are
generally considered to be low to very low, the impact would be considered to be of minor significance.
Indirect Impacts: Increased Marine Traffic
7.7.1.11 It is planned that there will be a maximum of 34 barge movements per day at the barging point and disturbance impacts on marine life such as underwater noise due to increased marine traffic may be potentially induced during the construction phase.
7.7.1.12
The results of the dive survey
for KTD EIA (Maunsell, 2008) indicated that very
limited marine life was observed in the study area (both spot-dive and
REA). No coral was recorded in the KTAC
and KTTS and the benthic species recorded within the Kai Tak area were mostly adapted to the
organic-enriched sediment and considered to be of low ecological significant.
Generally all the species identified in the study area are common and
widespread in
7.7.1.13
Results from KTD EIA study showed that no intertidal fauna was
recorded along the KTAC but only the algae Hincksia
mitchelliae was recorded (Maunsell,
2008). The habitat quality was considered as very poor due to the poor water
quality and has very limited ecological value. In general, the artificial intertidal habitats within
the Kai Tak area were very typical of
7.7.1.14
The benthic,
sub-tidal and intertidal habitats are of very low to
low ecological value and have
already been subjected to high levels of human disturbance and the increased in
marine traffic due to construction activities is not expected to substantially
exceed that of the baseline condition.
7.7.1.15
Given that
the temporary nature of the barge movements, the low
frequency of traffic and the low ecological value of the habitats at this area,
it is considered that the effects of increased marine traffic would be insignificant.
7.7.2
Summary of
Impact Evaluation
7.7.2.1
Summaries of the overall impact evaluation in the South Apron and Cha
Kwo Ling areas and for direct and indirect impacts are presented in Tables 7.4 below.
Table 7.4 Overall Impact Evaluation of Marine Habitats to be Indirectly
Affected
|
Criteria |
Hard Substrata Sub-tidal |
Benthic |
Intertidal |
|
|
Habitat Quality |
Low - Very
Low |
Very Low |
Very Low |
|
|
Species |
No coral were
recorded at Kai Tak Approach Channel (KTAC) and Kwun
Tong Typhoon Shelter (KTTS). |
Low species diversity and species abundance, but the
locally rare amphioxus Branchiostoma belcheri was
recorded. |
All of the
recorded faunal and flora were common local intertidal species with low
conservation importance. |
|
|
Size/ Abundance |
No direct impact to this habitat type |
No direct impact to this habitat type |
~100m of the intertidal habitat along the coastline |
|
|
Duration |
Indirect Impact Short-term disturbance impacts e.g. human, construction dust and
runoff during construction phase. No impact is anticipated during operation phase. |
Direct Impact Loss of habitat for the operation of barging point would be temporary
during construction phase. Indirect Impact Short-term disturbance impacts from humans, construction dust and
runoff during construction phase. No impact is anticipated during operation phase. |
||
|
Reversibility |
Indirect Impact Construction phase disturbance would be temporary and reversible. |
Direct Impact Habitat loss would be temporary and reversible. Indirect Impact Construction phase disturbance would be temporary and reversible. |
||
|
Magnitude |
Low |
Low |
Low |
|
|
Overall Impact
|
Insignificant |
Insignificant |
Minor |
|
7.7.3
Summary of Construction
Phase Impacts and Mitigation Measures
7.7.3.1
The
potential ecological impacts to marine habitats and key sensitive receivers in
the study area resulting from the project have been evaluated according to Table 1 of Annex 8 of the TM-EIAO and
are summarized in Table
7.5 below. The need for mitigation and enhancement measures are discussed in Section 7.9 below.
Table 7.5 Summary of Construction
Phase Impacts and Mitigation Measures
|
General Impact |
Specific Impact |
Severity of Impact |
Mitigation Required |
Enhancement Recommended |
|
Habitat Loss |
Temporary loss of inter-tidal habitat of approximately 100m. |
Insignificant |
No |
No |
|
Disturbance |
Deterioration
of Water Quality. |
Minor |
No(2) |
No |
|
|
Increased
Marine Traffic. |
Insignificant |
No |
No |
Note: (1): Dust and noise mitigation measures
recommended in Sections 4 and 5 of this EIA report would assist in minimising disturbance impacts.
(2): Water Quality
mitigation measures recommended in Section 6 of this EIA report would assist in
minimising disturbance impacts.
7.8
Operational Phase Impact Assessment
7.8.1.1
No marine
activities during the operation phase would be conducted and there are no
permanent structures to be constructed in the marine environment. Hence, no direct impacts are anticipated
during the operation phase. Potential
operational phase impacts on the marine environment could result from indirect
impacts associated with the deterioration of water quality.
7.8.1.2
There is a
risk to marine ecological resources due to potential chemical or oil spillages
arising from vehicle accidents during the operation of the project.
Although Dangerous Goods (DG) vehicles of Categories 1, 2 and 5 are
prohibited from using the tunnel, other tankers/vehicles carrying oil and
chemicals will be allowed to use the tunnel.
The majority of
7.8.1.3
As detailed in Section 6.5, while the road drainage system is
proposed to include oil and silt interceptors which will help to collect some
of a spill depending upon the amount, in the event that a major spill occurs, a
defined response plan will be required in order to, not only be enable the road
to reopen as soon as possible to minimise disruption to traffic, but also to
minimise effects on the marine ecological resources and water quality. All methods of spill clearance should be
environmentally acceptable and should not lead to pollution of the marine
environment. Details of the spill
response plan are provided in Section
6.5 and would be considered sufficient to protect marine ecological
resources and operations.
7.8.1.4
Potential water quality impact during operational phase could, also, be
due to road surface run-off from the at-grade road sections. Run-off
from road surfaces and leaks from vehicles may be contaminated,
however, the Trunk Road T2 will be installed with oil and silt interceptors to
screen the run-off before discharge. In
addition, as also detailed in Section
6.5, the road run-off would be notably diluted once it entered the marine
waters and should not result in a significant increase in concentrations of contaminants.
The total contaminant load in the road run-off will represent a small
increase in the natural contaminant load and should not result in a significant
detrimental impact on marine water quality especially when the small rainfall
volumes with respect to the tidal volume are taken into account. Based upon these factors, significant effects
on the water quality and, therefore, marine ecological resources, are not
predicted during
the operation phase with the implementation of the mitigation
measures detailed in Section 6.
7.8.1.5
The potential ecological impacts
during operation phase in the study area resulting from the project have been
evaluated according to Table 1 of Annex 8 of the TM-EIAO and area summarised in
Table 7.6 below. Mitigation and
enhancement measures are discussed in Section
7.9 below.
Table 7.6 Summary of Operation Phase Impacts and Mitigation Measures
|
General Impact |
Specific Impact |
Severity of Impact |
Mitigation Required |
Enhancement Recommended |
|
Disturbance |
Potential chemical or oil spillages |
Minor |
No(1) |
No |
|
|
Road surface run-off |
Minor |
No(1) |
No |
Note: (1):
Water Quality mitigation measures recommended in Section 6 of this EIA report
would assist in minimising disturbance impacts.
7.9
Mitigation Measures
7.9.1
Hierarchy of Impact Mitigation
7.9.1.1
Annex 16
of the EIAO-TM states that the general
policy for mitigation of significant ecological impacts, in order of priority,
is:
l
Avoidance:
Potential impacts should be avoided to the maximum extent practicable by
adopting suitable alternatives;
l
Minimisation: Unavoidable impacts should be minimised by taking appropriate
and practicable measures such as constraints on intensity of works operations
or timing of works operations; and
l
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.
7.9.1.2
As no moderate to severe significant ecological impacts have been
predicted for either the construction or operational
stages (Tables 7.5 and
7.6), no
ecologically specific mitigation measures in the form of avoidance,
minimisation and compensation measures are required. However, the design of the project has been
developed such as to avoid and minimise impacts to the surrounding environment
as far as possible, as discussed below.
7.9.2
Design Development for the Avoidance and Minimisation of Impacts
7.9.2.1
As described in Section 2, a detailed option assessment of various
alignments has been undertaken and the
preferred alignment selected on the basis that it was preferred on
environmental grounds, as well as meeting all the necessary engineering and
operational constraints and requirements. The Works Areas have, also, been
selected carefully and comprise sites already used as works areas or are on
disturbed and developed land.
7.9.2.2
In order to avoid the marine ecological impact, TBM is used instead of
IMT for tunnelling. The following
construction works that cold results in significant impacts on the marine
environment would be required by the IMT but would now be avoided by the
adoption of the TBM method:
l
temporary reclamation within the
l
temporary diversion of a submarine outfall;
l
demolition and reconstruction of the breakwaters for the Kwun Tong Typhoon
Shelter (KTTS);
l
use of the Shek O casting basin for the casting of IMT units;
l
temporary mooring point for IMT units within
l
disruption to the Kwun Tong
Typhoon Shelter.
7.9.2.3
Further minimisation of construction impacts can, also, be achieved
through good construction practice measures which have been recommended to be
implemented as follows:
l
avoid damage and disturbance to the remaining and surrounding natural
habitat;
l
placement of equipment in designated areas within the existing disturbed
land;
l
spoil heaps should be covered at all times;
l
construction activities should be restricted to the designated works
areas; and
l
disturbed areas to be reinstated immediately after
completion of the works.
7.9.2.4
Further mitigation measures for the specific construction and
operational phase impacts identified are discussed in the sections below.
7.9.3
Construction Phase Impact Mitigation
Habitat Loss
7.9.3.1
Impacts to marine ecological resources
have largely been avoided during the construction of the Trunk Road T2 through
the adoption of TBM tunnelling method avoiding the need for any dredging,
reclamation, filling activities and permanent above seabed structures in the
marine environment. As such, given there will be no habitat loss, the potential
impacts are considered as “insignificant” and, no ecological mitigation measures are
required.
Deterioration of Water Quality
7.9.3.2 The mitigation measures to be recommended in the water quality impact assessment (Section 6) to control water quality would serve, also, to protect ecological resources from indirect impacts due to deterioration of marine water quality and ensure no adverse impact on ecological resources would result from the Trunk Road T2 project. The predicted impacts from the potential deterioration of water quality affected ecological resources are “minor” but no ecological specific mitigation measures are required.
Increased Marine Traffic
7.9.3.3
Impacts associated with
potential disturbance to fauna from increase marine traffic during the
construction phase of the project are expected to the “insignificant” and, as
such, no ecological mitigation measures are required.
7.9.4
Operational Phase Impact Mitigation
Potential
Chemical or Oil spillages and Road Surface Run-off
7.9.4.1 “Minor” impacts to ecological resources due to potential accident spillages of chemical/oil and road surface run-off have been predicted as a result of the operation of the Trunk Road T2 project and no ecological specific mitigation measures are required. The implementation of the water quality mitigation measures recommended in the water quality impact assessment (Section 6), including provision of adequate drainage system with silt traps and oil interceptors, will help to minimise any impacts further.
7.10.1.1
The residual impacts refer to
the net impacts after mitigation, taking into account the background environmental conditions and the
impacts from existing, committed and planned projects. Residual impacts associated with the
construction and operation phases have been assessed but no quantification of
residual impacts is required.
7.10.1.2
With implementation of the above mitigation measures, significant
adverse residual impact on marine ecology due to deterioration in water quality
as a result of the construction works would not be predicted. In considering the limited ecological value
of marine habitats within or vicinity of the affected area and the temporary
nature of the impact, the residual impact would be considered to be acceptable.
7.10.1.3 In summary, it is predicted that the Trunk Road T2 project would have no long-term, unacceptable residual ecological impacts to marine ecological habitats and associated wildlife.
7.11.1.1 As detailed in the construction programme in Section 3, it is anticipated that construction works of the Trunk Road T2 will commence in December 2015 and the works last for about 5 years until the end of 2020. Other planned projects which will be undertaken concurrently and that have potential for cumulative direct and/or indirect marine ecological impacts in the study area are shown in Table 7.7 below and a full list of concurrent projects is provided in Appendix 3C.
Table 7.7 Potential Concurrent Projects Related to Water Quality
|
Project |
Project Proponent |
Construction Programme |
Major Works |
|
Project Involving
Marine-based Works |
|||
|
Central |
Highways
Department (HyD) |
2015-2020 |
Temporary reclamation and dredging |
|
Kai Tak Runway
Opening |
Civil
Engineering and Development Department (CEDD) |
2018 |
Opening and dredging |
|
Cross Bay Link
(CBL) |
Civil
Engineering and Development Department (CEDD) |
May 2017 to August 2018 |
Dredging and filling |
|
Tseung Kwan O – Lam Tin Tunnel (TKO-LTT) |
Civil
Engineering and Development Department (CEDD) |
January 2016 to December 2020 |
Reclamation works for the TKO section, piling works,
construction and decommission of two temporary barging points |
7.11.1.2
Although marine-based construction activities, dredging, reclamations
and caisson construction, would be required in the above concurrent projects,
no marine works that would affect the seabed would be undertaken by the Trunk
Road T2 project. As such, given that
proper implementation of good site practice to control site run-off, no
cumulative impacts on the marine ecological habitats and associated wildlife
resulting from Trunk Road T2 project would be expected.
7.11.1.3
Loss of approximately 100m of intertidal habitat due to the operation of
barging point at the Kai Tak South Apron cause only minor contributions to the
cumulative impacts. The Trunk Road T2 habitat loss area is relatively
small overall and the contribution of this project alone and to the cumulative
impacts is expected to be small. As such, the majority of the cumulative
impacts would come from other projects (e.g. Kai Tak runway opening) because of
their large size and permanent and irreversible habitat loss impacts.
7.12
Ecological
Monitoring and Audit Requirements
7.12.1.1 The implementation of the ecological mitigation measures described in Section 7.10 will be checked as part of the EM&A procedures during the construction period. Environmental audit is needed to ensure the ecological impacts from the construction and operation of the Project is kept within acceptable levels, and the application and mitigation measures are practical and effective. Further details of the EM&A requirements are detailed in Section 12 of this report and in the EM&A Manual.
7.13.1.1
Within the 500m study envelope of the Trunk Road T2 alignment project
boundary, no important ecological sensitive receivers, such as marine parks, or
other areas of conservation importance, are found. The species of conservation
interest identified in the study area comprise corals only.
7.13.1.2
The ecological habitats identified include artificial coastline, hard
sub-tidal, benthic and intertidal habitat which have less ecological value.
7.13.1.3
In order to avoid the marine ecological impacts during construction
phase, the TBM method of tunnelling has been adopted instead of the IMT
method. As such, there will be no
permanent habitat loss predicted and not direct disturbance to the marine
environment. The potential for construction stage site run-off may lead to
temporary water quality issues and an increase in local suspended solids for a
short period of time during construction phase.
However, these impacts are predicted to be minor and can be further
controlled by the implementation of the recommendations in the Water Quality Section 6 and ProPECC
PN 1/94 Construction Site Drainage and, thus, they would be temporary and
negligible with good site practices in place during the construction
phase. Given that the ecological value
of the surrounding marine habitats are generally considered to be low to very
low, the impact would be considered to be of minor significance and
acceptable. In addition, the extent of
ecology nuisance would be unlikely to induce any adverse impacts to the biota
or risk to marine life.
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