This section presents the
findings of an assessment of potential impacts on existing capture and culture
fisheries, including fisheries resources, fishing operations and fish/oyster culture
activities, from the construction and operation of the proposed Project.
The criteria for evaluating
fisheries impacts are stated in the EIAO-TM. Annex
17 of the EIAO-TM prescribes the
general approach and methodology for assessing fisheries impacts caused by a
project or proposal, to allow a complete and objective identification,
prediction and evaluation of the potential impacts. EIAO-TM
Annex 9 recommends the criteria that are to be used for evaluation of
fisheries impacts.
·
Fisheries Protection
Ordinance (Cap. 171),
which provides for conservation of fish and other aquatic life, regulates
fishing practices and prevents activities detrimental to the fishing industry;
·
Marine Fish Culture
Ordinance (Cap. 353),
which regulates and protects marine fish culture and other related activities
and requires all marine fish culture activity to operate under license in
designated Fish Culture Zones;
·
Water Pollution Control
Ordinance (Cap. 358),
which aims to control water pollution in Hong Kong waters. Water Control Zones (WCZs) are
designated with individual water quality objectives to promote the conservation
and best use of those waters in the public interest; and
·
Environmental Impact
Assessment Ordinance (Cap. 499), Section 5(7) – Environmental Impact Assessment Study
Brief No. ESB-286/2015 Section 3.4.10.2 and Appendix F which outline the key
fisheries impacts to be reviewed and assessed in the EIA report.
The assessment area for
fisheries included areas within 500m distance from the boundaries of the
Project Site (including its associated works) (Figure
11.1). Marine waters beyond
the 500m Assessment Area is also reviewed to provide baseline conditions of the
broader Black Point area. For a
detailed description of the physical and biological characteristics of the
marine environment of the assessment area please refer to Sections 7 and 10
respectively.
Commercial fishing
operations in Hong Kong are broadly classified into culture and capture
fisheries.
The pond fish culture
industry is centred in the northwest New Territories. Fish ponds are either
freshwater or brackish and a vast majority of pond farms are engaged in
polyculture of carps with tilapia or grey mullet.
Marine-based
culture fishery operations occur at 26 Fish Culture Zones (FCZs) which
altogether occupy about 209 ha of Hong Kong waters. They involve rearing of marine fish from
fry or fingerlings to marketable size in cages suspended by floating rafts
usually in sheltered coastal areas/ embayments. Fish farms are typically small scale,
family-run operations comprising only one or two rafts with an average size of
about 290 m2.
With effect
from June 2002, the marine fish culture licence is transferable. The existing moratorium for FCZs has been
reviewed and three new measures are proposed to promote the sustainable
development of the local fisheries industry ([1]),
including:
·
Issue
new marine fish culture licences in three FCZs (i.e. O Pui Tong, Wong Wan and
Sham Wan FCZs) with approximately 30 new marine fish culture license to be
issued at the initial stage;
·
Expand
the existing FCZ at Yim Tin Tsai; and
·
Identify
any potential area for designation of new FCZs.
In 2014, the marine fish
culture industry produced about 1,255 tonnes of fish valued at HK$115 million
which accounts for about 6% of local demand for live marine fish. Some recent figures on the local marine
culture fisheries are presented in Table 11.1.
Table 11.1 Marine Culture Fisheries Summary Statistics
2002 - 2014 (source: AFCD)
|
AFCD Estimate |
2002 |
2003 |
2004 |
2005 |
2006 |
2007 |
2008 |
2009 |
2010 |
2011 |
2012 |
2013 |
2014 |
|
Licensed
Mariculturists |
1,237 |
1,157 |
1,125 |
1,104 |
1,081 |
1,072 |
1,060 |
1,050 |
1,035 |
1,010 |
1,008 |
987 |
968 |
|
Production (tonnes) |
1,210 |
1,490 |
1,540 |
1,540 |
1,490 |
1,530 |
1,370 |
1,437 |
1,512 |
1,185 |
1,299 |
1,005 |
1,255 |
|
Value (HK$ million) |
57 |
76 |
79 |
76 |
89 |
99 |
82 |
92 |
118 |
94 |
117 |
94 |
115 |
Capture
fisheries is primarily concentrated in the waters of Hong Kong, the Pearl River
Estuary and the adjacent continental shelf of the South and East China Seas ([2]). The Agriculture, Fisheries and
Conservation Department (AFCD) reported that in 2014 an estimated 160,789 tonnes
of fish was produced, which was equivalent to an economic value of about
HK$2,530 million ([3]). In addition, 9,400 local fishermen with
approximately 4,500 vessels were servicing in the fishing industry ([4]). The major fishing methods include trawling,
long-lining, gill-netting and purse-seining with the majority of the total
catch obtained through trawling.
Based
on the latest data from AFCD Port Survey 2006, the highest fisheries production
(600 to 1,000 kg ha-1) in Hong Kong was recorded in the vicinity of
the Ninepin Island Group, Po Toi and Tap Mun ([5]). These areas also recorded the highest
number of fishing vessels. Scad (Carangidae), shrimp,
rabbitfish (Siganidae), squid, croaker (Sciaenidae), crab, mullet (Mugilidae),
sardine (Clupeidae), seabream (Sparidae)
and anchovy (Engraulidae) were the top 10 families
captured in Hong Kong waters.
To
promote the sustainable development of fishing industry and to conserve
fisheries resources in Hong Kong waters, AFCD has implemented a number of
fisheries management and conservation measures. On 31 December 2012, an outright
trawling ban was put into effect in an attempt to restore the seabed and the
depleted fisheries resources ([6]). To complement the trawl ban and bring
local fisheries industry back to a sustainable path, the government seeks to
implement other fisheries management measures through legislative amendments to
the Fisheries Protection Ordinance
(Cap. 171). These measures include:
(1) setting up a registration system for local fishing vessels; (2) limiting
new entrants to control the fishing number of fishing vessel and fishing
effort; (3) restricting fishing activities of non-fishing vessels and
prohibiting fishing activities of non-local fishing vessels; (4) designating
fisheries protection areas; (5) habitat enhancement and restoration (i.e.
artificial reefs); and (6) fish restocking trials.
Since
1999, Mainland Authorities have implemented a fishing moratorium for South
China Sea fishing grounds for about 2.5 months during mid-summer (between mid-May to August).
The moratorium prohibits fishing activity by the Hong Kong fleet outside
of Hong Kong waters except by gill-netting, long-lining, hand-lining and cage
trapping.
There is no FCZ or fish
pond located close to the proposed Project (Figure
11.1). The closest AFCD
designated FCZ is located at Ma Wan which is over 20 km from the Project. Existing pond fish culture activities in
Hong Kong are centred in the northwest New Territories extended from the Inner
Deep Bay Ramsar Site, which is over 10 km from the
Project Site.
Despite the long
established oyster farming practice on the Deep Bay mudflats, there are no
gazetted oyster farming locations in Hong Kong. The oyster production area located along
the shore from Tsim Bei Tsui to Pak Nai (Figure
11.1) is about 3.5 km from the proposed Project.
A desktop review of
existing information on commercial fisheries resources and fishing operations
in waters of the Assessment Area has been undertaken, and the most up-to-date
information was obtained primarily from the AFCD Port Survey 2006 and other
approved EIA and fisheries studies.
The area and number of
vessels operating in the assessment area during 2005 are presented in Figure 11.2
([7]). It should be noted that trawling was
still allowed at time when the Port Survey was conducted in 2005. Very low numbers of fishing vessels (10
– 50 vessels), mostly shrimp trawlers, hang trawlers,
gill netters and sampans, operated within the Assessment Area and in outer Deep
Bay. Elsewhere in Black Point and Tuen Mun, low numbers of vessels
(50 -100 vessels) were recorded in Lung Kwu Tan and
off Castle Peak, whereas moderate numbers of vessels (100 – 400 vessels) were
recorded near the Sha Chau and Lung Kwu Chau Marine
Park (SCLKCMP) (Figure 11.2).
In Deep Bay waters where
the Assessment Area is, the production of adult fish and value of catch ranked
12th among the 12 fishing sectors in Hong Kong waters, and in 1998
an estimated annual catch of 73 tonnes of adult fish and zero fry was recorded
in these waters ([8]).
More recent data from the
AFCD Port Survey 2006 indicated that fisheries production in the Assessment
Area and outer Deep Bay was very low, with £ 50 kg ha-1 for
adult fish with no documented fish fry production and accounting for £ HK$ 500 ha-1 in
value (Figures
11.3 to 11.5)
([9]). Elsewhere in Black Point and Tuen Mun, moderate level of adult
fisheries production (200 – 400 kg ha-1) were recorded near the
SCLKCMP, accounting for HK$ 2,000 – 10,000 ha-1 in value (Figures
11.3 and 11.4). Low to moderate level of adult fisheries
production (50 – 200 kg ha-1) with HK$ 500 – 2,000 ha-1
in value was recorded in Lung Kwu Tan and off Castle
Peak.
Results of the Port Survey
2006 thus suggested that waters in outer Deep Bay and the Assessment Area are
not key fishing areas with very low fisheries production due to the shallow
water depths which constrain vessel navigation and the abundance of cargo vessels
that ply the waters between the Shenzhen River and the Pearl River. It is concluded that the level of
fishing operations, fisheries production and catch value in these waters are
very low comparing to elsewhere in Hong Kong waters.
Results of the trawling
surveys conducted by ERM in 1996-1997 (Figure
11.6) ([10])
showed that a majority of species captured in outer Deep Bay near the
Assessment Area were prawn (e.g. Trachysalambria curvirostris), croaker (e.g. Collichthys lucida) and mantis shrimp (e.g. Oratosquilla oratoria, Dictyosquilla foveolata). In gill-netting surveys of the same
study, the most abundant fisheries resources captured (by weight) were sardine
(e.g. Clupanodon punctatus), flathead (e.g. Platycephalus indicus),
croaker (e.g. Collichthys lucida),
anchovy (e.g. Thryssa hamiltonii)
and puffer fish (e.g. Takifugu alboplumbeus). Similar findings were reported in the
AFCD Port Survey 2006, with catch in the outer Deep Bay including the
Assessment Area containing a very low number of adult fish production (£ 50 kg ha-1) of scad, shrimp, rabbitfish, squid, croaker, crab, sardine,
seabream and anchovy ([11]).
More recent fisheries
surveys were carried out in 2013 in North Lantau waters and SCLKCMP by the EIA
study for the Expansion of Hong Kong International Airport into a Three-Runway
System (3RS EIA) ([12]). The 3RS EIA concluded that the North
Lantau waters were of moderate fisheries production with species of no or low
commercial values, namely anchovy (Thryssa kammalensis) and sardine (Sardinella albella). In the SCLKCMP, moderate to high
fisheries production with species of no to high commercial
values were recorded, in which the dominant species were shad (Nematalosa nasus) and sardine (Sardinella albella).
The routine marine biota
monitoring for the Environmental Monitoring & Audit (EM&A) of the
Dredging, Management and Capping of Contaminated Sediment Disposal Facility to
the South of the Brothers ([13])
and EM&A for Contaminated Mud Pit V at Sha Chau ([14])
suggested that the fisheries resources of North Lantau and SCLKCMP consisted of
species with low or no commercial values, namely the snail Turritella terebra
and the crab Charybdis spp..
Findings from the above
previous surveys suggested that the fisheries resources in the Assessment Area
and its vicinity are predominantly species with no or low commercial value,
with the exception of SCLKCMP where some high-valued species were recorded.
The northern Lantau waters
were previously identified in 1998 as fisheries spawning grounds for high value
commercial species (Figure
11.1) ([15]). This area is approximately 10 km long
(from Tai Mo To of the Brothers to Lung Kwu Chau) and
5 km wide (from Castle Peak to the northernmost tip of the airport). Leiognathus brevirostris (ponyfish), Lateolabrax japonicus
(seabass/ perch) and Clupanodon punctatus (gizzard shad) were examples
of the main commercial fish species recorded in the North Lantau spawning
area. In Hong Kong, spawning period
differs among fisheries species with the majority of commercial species
aggregate and spawn in the open waters during the period from June to September
([16]). The recognised northern Lantau spawning
area is located south of the proposed Project at a distance of about 4 km (Figure
11.1),
The recent ichthyoplankton and post-larvae surveys
in the identified fisheries spawning grounds at the North Lantau waters in 2013
by the 3RS EIA reported
that the ichthyoplankton and post-larvae
densities (1.13
– 1.16 larvae m-3) and family richness (6.50 - 6.79) were low, and
mostly consisted of families of low commercial values ([17]).
The AFCD has been
undertaking a programme to enhance existing marine habitats and fisheries
resources through the siting, construction and deployment of artificial reefs
(ARs). Generally ARs provide hard
bottom, high profile habitat in areas without natural cover and may potentially
act as fish enhancement devices. In
March 2000, the Sha Chau AR was deployed with the key objective of enhancing
the marine habitat quality and fisheries resources (Figure
11.1) ([18]). A total of 42 units of concrete-coated
container and 24 units of ferro-cement river barges
with a total volume of 5,580 m3 have been deployed on the
seabed. They are located at least
7.8 km away from the proposed Project.
Based on the baseline
information provided above, the importance of the fisheries within the
Assessment Area is evaluated. The
fishing grounds within the Assessment Area are considered as of very low
commercial value. The small size
and subsequent low value of the catches characterise the waters of the
Assessment Area as of low importance to the Hong Kong fishing industry.
According to Annex 9 of the EIAO-TM, spawning grounds can be regarded as an important habitat
type as they are critical to the regeneration and long-term survival of many
organisms and their populations. No
spawning area has been identified within the footprint of the proposed
Project. The closest recognised
spawning area is located approximately 4 km south of the Project.
Based on the preceding
review of the available information on the capture and culture fisheries of the
waters in the vicinity of the proposed Project, the potential sensitive
receivers that may be affected by the Project activities are identified as
follows:
·
Recognised
spawning ground of commercial fisheries resources in North Lantau (south of the
proposed Project at a distance of about 4 km);
·
Artificial
reefs in the Sha Chau and Lung Kwu Chau Marine Park
(located at least 7.8 km from the proposed Project); and
·
Oyster
production area at Deep Bay (about 3.5 km from the proposed Project).
The locations of the
sensitive receivers are shown in Figure
11.1. FCZs and pond fish
culture activities in the northwest New Territories are not expected to be
affected by the Project due to their distances from the Project site and they
are thus not considered to be sensitive receivers.
A desktop literature review
of baseline fisheries conditions was conducted for the purpose of establishing
the fisheries importance of the waters in the Assessment Area and its
vicinity. Information from the
water quality impact assessment (Section
7) was examined to assess potentially affected area by perturbations to
water quality parameters.
The relevant desktop
information from previous studies between 1998 and 2014 were reviewed (Figure
11.6) and it is considered sufficient to evaluate the importance of
potentially impacted fisheries resources and fishing operations within the
Assessment Area. In addition, the
fisheries interview surveys conducted in 2013 for the 3RS EIA ([19])
suggested that the information presented in Port Survey 2006 is still valid and
sufficiently comprehensive to provide an up-to-date baseline for fisheries
impact assessment. Therefore, no
information gap was identified and fisheries survey is considered not required
for the current EIA study of this Project.
The potential impacts due
to the construction and operation of the Project were then assessed (with
reference to the EIAO-TM Annex 17
guidelines) and the impacts evaluated (with reference to the criteria in EIAO-TM Annex 9).
As discussed in Section 3, no marine works will be
required for the construction of the CCGT Unit No.1. No loss or direct disturbance to fishing
grounds and fisheries habitats is expected, and hence no unacceptable impact to
fisheries resources and fishing operations is anticipated.
For the land-based phased
construction of CCGT Unit. No.1 and No.2 (if installed), indirect impacts to
fisheries resources, habitats and fishing operations may include changes in
water quality from land-based discharges and site runoff from construction
workforce, as described in the water quality impact assessment in Section 7. Land-based discharges and runoff from
the work site, particularly during civil works, excavation and backfilling
works, may contain suspended solids which could be a source of water
pollution. Uncontrolled disposal of
debris and rubbish such as packaging, construction materials and refuse and spillages
of chemicals stored on-site, such as oil, diesel and solvents would also result
in contamination of construction site runoff. It is anticipated that no unacceptable
water quality impacts would arise from the land-based works if standard site
management practices and mitigation measures, described in Section 7.9.1, are in place and properly implemented. Also, effluent from chemical washing of
the new CCGT units before commissioning would be discharged into the existing
Effluent Treatment Facilities of the BPPS which handles similar effluent from
chemical cleaning event from existing CCGT units, and would be neutralised and
treated to acceptable standards specified in the existing / future WPCO
discharge licence before discharge.
Consequently, indirect impacts on fisheries would be managed to within
acceptable levels.
Should CCGT Unit No.2 be
installed, the construction of the proposed submarine cooling water intake and
outfall will involve minor dredging works adjacent to the seawall of the
BPPS. Potential impacts to
fisheries resources and fishing operations arising from these works may be
divided into those related to:
·
Direct
disturbances of fisheries habitat and fishing ground;
·
Underwater
sound generated from marine construction activities; and
·
Perturbations
to key water quality parameters.
With respect to fish
culture activities, construction activities of the Project will not have any
direct impacts, such as drawdown of water table, disturbance or restriction, on
these activities. Considering the
large separation distance, indirect impacts from construction activities,
including perturbation to water quality and underwater sound, will be
negligible. Consequently, no
unacceptable impacts to culture fisheries are expected.
Direct impacts to fisheries
resources, habitats and fishing operations include disturbance caused by the
proposed dredging works. There will
be no permanent loss of fisheries habitat and fishing ground due to the
Project, as the proposed submarine cooling water intake and outfall would not
occupy the water column and the backfilling of the seabed as hard substrate
following the dredging and installation works can continue to function as
fisheries habitats. The proposed
dredging works is expected to cause temporary disturbance to a seabed area of
approximately 2 ha within the marine works areas. Considering the temporary nature of the
disturbance (about seven months for the marine construction works), small
extent of the area which is next to the BPPS seawall and the low fisheries
importance of this area, unacceptable impacts on the fishery resources and
activities are not expected.
Fisheries resources are expected to return to the area following the
cessation of marine construction activities. Issuance of Marine Department Notice or
other notifications is expected to reduce the risk of collision of increased
marine traffic and fishing vessels to within acceptable levels.
Intermittent sounds, which
occur during activities such as dredging and marine vessel movement, may have
an impact on fisheries resources during the construction phase. Potential effects of increased
underwater sound include physiological stress, avoidance and injury (at high
pressure levels). The level of
impact is however dependent upon background sound, number of fish present, type
of species affected, attenuation properties of seabed sediments and hearing
capabilities of the species affected, etc.
Most marine invertebrates
do not possess air-filled space and thus it is generally considered that sound
would have limited physiological or behavioural effects on marine
invertebrates, except if they are located within a few metres of the sound
source. Therefore underwater sound
generated from marine works is expected to have negligible impact on fisheries
resources such as crustaceans which are not reported to be abundant in the
Assessment Area.
Fish, however, can detect
underwater sound vibrations through two ways, the lateral line system and the
inner ear for species containing air-filled swim bladders. Anthropogenic underwater sounds
associated with vessels for this Project, such as barges, guard vessels and
dredgers, exhibit major energy below 1,000 Hz and sound levels of between 170
and 190 dB re 1 μPa at 1 m and may be audible to most
fish species ([20]). Waters within the Assessment Area and
its vicinity is subject to relatively high levels of marine traffic by similar
types of vessels; therefore it is reasonable to assume that fish in these
waters are habituated to a relatively high background level of underwater
sound, and a small increase in vessel activity associated with the construction
of this Project is not anticipated to result in unacceptable impacts on
fisheries resources.
Indirect impacts to
fisheries resources, habitats and fishing operations during the construction
phase of the Project include sediment release associated with the marine
works. Potential impacts to water
quality from sediment release due to marine dredging at submarine cooling water
intake and outfall are described in the water quality impact assessment in Section 7. These potential impacts are as follows:
·
Increased
concentrations of suspended solids (SS);
·
Decreased
dissolved oxygen (DO) concentrations;
·
An
increase in nutrient concentrations in the water column.
Dredging works for CCGT
Unit No.2 are expected to generate SS within the water column and result in
increased sediment deposition in close proximity of the works areas. The modelling works have analysed SS
dispersion from construction works (Section
7.7.1).
Fluxes of SS naturally
occur in the marine environment and as a result, fish have evolved behavioural
adaptations to tolerate changes in SS load (e.g. clearing their gills by
flushing water over them).
Concentrations of SS generated by these marine construction activities
are expected to be greater, particularly in the immediate vicinity of the
proposed works areas. Beyond the
active marine works areas, dispersion can be expected to lead to a rapid
decline in the SS concentrations.
Compared to adult fish,
larvae and post-juvenile fish are relatively more susceptible to variations in
SS concentrations as their sensory system is less developed. Adult fish are more likely to move away
from area of disturbance when they detect sufficiently elevated SS
concentrations and therefore are unlikely to be significantly impacted.
The SS level at which fish
move into clearer water is defined as the tolerance threshold which varies
among species and different stages of the life cycle. If SS levels exceed tolerance thresholds
and the fish are not able to move away from the affected area, the fish are
likely to become stressed, injured and may eventually die. The rate, timing and duration of SS
elevations influence the type and extent of impacts upon fish and potentially
crustaceans ([21])
([22]).
Findings from literature
reviews indicated that lethal responses had not been reported in adult fish at
SS values below 125 mg L-1 ([23])
and that sub-lethal effects were only observed when levels exceeded 90 mg L-1
([24]). However, as part of a study for AFCD, Consultancy Study on Fisheries and Marine
Ecological Criteria for Impact Assessment guideline values have been
identified for fisheries and selected marine ecological sensitive
receivers. The values are based on
international marine water quality guidelines for the protection of ecosystems
([25]). The AFCD study recommends a maximum SS
concentration of 50 mg L-1 (based on half of the no observable
effect concentrations). However,
the study cautioned that site-specific data should be considered in
environmental assessments on a case-by-case basis. In order to provide a more conservative
assessment (i.e. with a lower tolerance criterion), the Water Quality Objectives
(WQOs) for SS elevation are adopted instead in this study as the assessment
criteria for fisheries sensitive receivers.
As discussed in Section 7.7.1, the water quality
modelling results have indicated that at all fisheries sensitive receivers, SS
elevations as a result of the proposed dredging works at the cooling water
intake and outfall for CCGT Unit No.2 are predicted to be compliant with the
relevant WQOs for both wet and dry seasons (Table
7.11 to 7.14). Elevated levels of SS as a result of
these works are expected to be temporary in nature and localised to the
proximity of marine works areas that are considered as of low fisheries
importance. With the implementation
of mitigation measures proposed in the water quality impact assessment in Section 7, such as the use of silt
curtains and reduced working rate, potential impacts to fisheries would be
further reduced. As such,
unacceptable impacts from such works on fisheries are not expected to occur. The water quality assessment has also
shown that unacceptable water quality impacts due to the release of heavy
metals and organic micro-pollutants associated with suspended solids are not
expected to occur (see Section 7.7.4).
Finally, it should be noted
that the Assessment Area is at the mouth of Deep Bay on the eastern bank of the
Pearl River Estuary. As a result of
discharges from the Pearl River and the Shenzhen River in Deep Bay, the
background variation in SS levels is acknowledged as being high. Water quality data gathered by EPD has
revealed that in the vicinity of Assessment Area SS values can reach over 88.5 mgL-1 (Table
7.2). Therefore, impacts
to fisheries resources as a result of potential elevations of SS from the
construction works are not expected to occur.
The relationships between
SS and DO are complex, with elevated SS in the water column together with a
number of other factors to reduce DO concentrations. Elevated SS (and turbidity) reduces
light penetration, lowers the rate of photosynthesis by phytoplankton (ie primary productivity) and thus lowers the rate of oxygen
production in the water column.
Furthermore, the potential release of sediment contaminants into the
water column may consume the DO in the receiving water. The resulting overall DO depletion has
the potential to cause an adverse effect on the eggs and larvae of fish and
crustaceans, as at these stages of development high levels of oxygen in the
water are required for growth to support high metabolic growth rates.
The results of the water
quality assessment (see Section 7.7.2)
have indicated that DO depletion as a result of dispersion of sediment plumes
associated with marine works of the Project are predicted to be quite low (<
0.1 mg/L) and remain compliant with the annual WQO DO criteria (0.19 – 1.09
mg/L) at all fisheries sensitive receivers. Therefore, no unacceptable impacts to
fisheries from the reduction of DO concentration is expected to occur.
High levels of nutrients
(total inorganic nitrogen - TIN and ammonia) released from dredged sediments to
seawater may potentially cause rapid increases in phytoplankton population, on
occasions to the point that an algal bloom occurs. An intense algal bloom can cause sharp
decreases in the levels of DO. This
decrease would initially occur in the surface water, and then spread to deeper
water as dead algae fall through the water column and decompose on the seabed.
The water quality modelling
results have indicated that elevated nutrients concentrations are expected to
remain compliant with WQOs at all fisheries sensitive receivers (see Section 7.7.3). Unacceptable impacts to fisheries are
thus not expected to occur.
The potential for release
of contaminants from dredged sediments has been assessed in Section 7.7.4, whereas, a comprehensive
set of data on the marine sediment quality is provided in Section 8 – Waste Management.
As discussed in Section 7.7.4, unacceptable water
quality impacts due to the potential leaching of heavy metals and micro-organic
pollutants from the disturbed sediments into the water column are not expected
to occur. Impacts on fisheries
resources due to bioaccumulation of released contaminants from dredged
sediments are thus not expected to occur.
In summary, predicted
levels of SS, DO, nutrient and contaminant concentrations as a result of
dredging works of this Project are anticipated to be in compliance with the
relevant assessment criteria.
Unacceptable indirect water quality impacts from sediment release on
fisheries sensitive receivers are thus not expected to occur.
The potential impacts of
the operational phase of the Project on the fisheries of the Assessment Area
include:
·
Impingement
and entrainment of fisheries resources at the cooling water intake;
·
Secondary
impacts arising from the alteration of marine water quality due to thermal
discharges and other pollution load from outfall; and
·
Change
in water quality during maintenance dredging at the proposed cooling water intake
and outfall for CCGT Unit No.2.
For fish culture
activities, operational activities of the Project will not have any direct
impacts, such as disturbance or restriction, on these activities. Considering the large separation
distance, indirect impacts from operational activities such as perturbation to
water quality will be negligible.
Consequently, no unacceptable impacts to culture fisheries are expected.
From a fisheries
perspective, the inflowing seawater at the cooling water intake may have
negative effects on fish, fish eggs and crustacean due to the physical damage
caused by collisions with the screening system (impingement) and due to their
uptake to the process system (entrainment). The swimming speeds of juvenile and
larval fishes vary greatly but are generally slower than the water velocity of
the intake system. Owing to their
larger size, juvenile fish are generally more susceptible to impingement,
whilst fish and crustacean larvae and eggs are more exposed to entrainment, as
their small size enables them to pass through the screening system ([26])
([27]). Adult fish are in general much less
susceptible to risks of impingement and entrainment since they can swim at higher
velocities and hence can counteract the intake velocity and actively move away.
The rate of water intake
would be 950,400 m3 per day for each of the additional CCGT units,
in comparison to the current maximum cooling water intake rate of 4,600,000 m3
per day at the BPPS with eight existing CCGT units. Whilst it is acknowledged that the
intake of seawater may minimally increase the natural mortality rate of fish
larvae, crustaceans and fish eggs due to impingement and entrainment, it has
been noted that the significance of such impacts is strongly dependent on the
ecological sensitivity and the productivity of the impacted area as well as the
rate of water intake. No spawning
and nursery grounds has been identified within and in the immediate vicinity of
the cooling water intake (Section 11.3), and it is useful to note that the existing box culvert
supplementary seawater intake of the BPPS for use by CCGT Unit No.1 and the new cooling
water intake for CCGT Unit No.2 are located next to artificial seawall where
the supply of ichthyoplankton and fish larvae would
appear limited. The recognised spawning ground at North
Lantau, where low densities and richness of ichthyoplankton and fish larvae were reported, is over
4 km away are considered unlikely to be affected by the
operation of this Project.
Considering the low sensitivity and productivity in ichthyoplankton
and fish larvae in the Assessment Area, unacceptable impacts due to impingement
and entrainment of fisheries resources in not anticipated. The screen mesh size and design of the
new cooling water intake will be determined during detailed engineering design,
and the use of suitable screen mesh size and intake velocity would greatly
reduce the impingement and entrainment mortality of fish larvae, crustaceans
and fish eggs, if present ([28]).
As discussed in Section 7.8.1, the predicted
elevation in mean and maximum water temperature is equal to or below 0.4 °C at all
fisheries sensitive receivers for the operation of CCGT Unit No.1, while the predicted
elevation in mean and maximum water temperature is equal to or below 0.6 °C at
all fisheries sensitive receivers for the operation of two additional CCGT
units. In both cases, the most
impacted fisheries sensitive receiver is the recognised
fisheries spawning ground in North Lantau.
As shown in the modelling results, the predicted level of ambient water
temperature is well below the proposed assessment criteria based on WQO, and is
considered to be within or similar to range of daily fluctuation. No
unacceptable water quality impact from the increase in thermal discharge from
the phased operation of CCGT Unit No.1 and No.2 is expected.
For the discharge of total
residual chlorine, other pollution load and effluent from chemical washing from
the operation of the Project, the modelling results in Section 7.8.2 showed that all concerned discharge would be
compliant with the corresponding WQOs and/or discharge standard for the phased operation of CCGT Unit No.1 and No.2.
Thus, no unacceptable secondary impact on fisheries
from the increase in total residual chlorine and other pollution load discharge
from the proposed Project is expected.
Maintenance dredging near
the proposed cooling water intake and outfall of CCGT Unit No.2 would be
required at regular intervals. The
extent of dredging would be similar to that of the proposed dredging under construction
phase, yet the thickness and total volume of sediment to be removed would be
much smaller. Thus, the potential
water quality impacts on fisheries sensitive receivers from operation phase
maintenance dredging are considered similar or less significant than those for
the construction phase. With the
implementation of mitigation measures proposed in the water quality impact
assessment in Section 7, such as the
use of silt curtains and reduced working rate, potential impacts to fisheries
would be reduced to within acceptable levels. Consequently, no unacceptable secondary impact on fisheries sensitive receivers from the
maintenance dredging is expected.
From the information
presented above, the fisheries impact associated with the Project is not
considered to be significant. An
evaluation of the impacts according to Annex
9 of the EIAO-TM is presented
below:
·
Nature of Impact: Temporary disturbance to fisheries
habitats and fishing grounds in the marine works areas of CCGT Unit No.2 is
expected as a result of the dredging works. Potential impacts of elevated levels of
underwater sound as a result of construction activities are not expected to be
unacceptable. Temporary impacts to
pelagic and demersal fisheries resources as a result of minor perturbations to
water quality are predicted to occur in the immediate vicinity of marine
construction works. No significant
adverse impacts to fisheries resources are expected from the impingement and
entrainment of fish and crustacean larvae or eggs in the intake systems. Unacceptable secondary impacts on
fisheries resources, due to changes in water quality and dispersion of cooling
water discharges from the phased operation of CCGT Unit No.1 and
No.2, are not
expected.
·
Size of Affected Area: No permanent loss of fisheries habitats
and fishing ground is anticipated during the construction and operation of the
Project. Temporary disturbance to
about 2 ha of fisheries habitats and fishing ground during marine dredging, which
is considered to be insignificant for local fisheries resources and fishing
operations given the very small size of habitat affected and low fisheries
importance of these waters.
·
Loss of Fisheries
Resources/ Production: Based on the findings from Port Survey
2006, the value of the fisheries resources/production of the marine waters of
the Assessment Area is low (< 50 kg ha-1) in comparison to other
waters in Hong Kong. In the context
of the total captured fisheries production in Hong Kong, the Project would only
result in a very minor loss in fisheries resources/production in Hong
Kong. Thus impact of loss of
fisheries resources/ production is considered to be of negligible significance.
·
Destruction and Disturbance
of Nursery and Spawning Grounds: No nursery
or spawning grounds have been identified within the direct footprint of the
Project. In North Lantau, a
recognised spawning area for fisheries resources lies about 4 km from the
proposed Project. As the water
quality modelling results have indicated that impacts to water quality are predicted
to be minimal, impacts to important spawning grounds are not expected to occur.
·
Impact on Fishing Activity: Due to the small size of the affected
area and the low intensity of the fishing operations, impacts on fishing
activity are expected to be minimal.
Potential
obstruction to fishing activities due to the construction of the proposed
cooling water intake and outfall is not anticipated as it will be installed
along the BPPS seawall. The seabed
temporarily affected by the proposed dredging works is expected to be minimal.
·
Impact on Aquaculture
Activity: Fish ponds and FCZs are too remote (over
10 km and 20 km respectively) to be affected by the Project. Oyster production areas are located at
some distance (about 3.5 km) from the Project Site. Also no impact has been identified on
culture activities as predicted SS elevations are compliant with the relevant assessment
criteria/ standards.
In accordance with the
guidelines in the EIAO-TM on
fisheries impact assessment, the policy adopted in this EIA for mitigating
impacts to fisheries, are:
·
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 confining works in
specific area or season; and
·
Compensation: When all possible mitigation measures
have been exhausted and there are still significant residual impacts or when
the impacts are permanent and irreversible, consideration shall be given to
off-site compensation. It may
include enhancement of fisheries resources and habitats elsewhere.
Construction impacts to
fisheries resources, habitats and fishing operations have largely been avoided
(i.e. important spawning area of commercial fisheries resources) and reduced
through proper planning and design of the works, in particular those associated
with the dredging works (e.g. minimisation of dredging works area). The marine works have been designed to
confirm compliance with the assessment criteria at sensitive receivers and
control water quality impacts to within acceptable levels and water quality
mitigation measures will be implemented to further avoid/reduce potential
impacts (see Section 7). These measures are expected to control
and reduce potential impacts to fisheries resources as well, and no
fisheries-specific mitigation measures or compensation are thus required during
construction.
No unacceptable adverse
impacts to fisheries resources, habitats and fishing operations are expected to
occur during the operation phase of the Project. Compliance with the relevant discharge
standards to control water quality impacts to within acceptable levels is also
expected to control impacts to fisheries resources. Furthermore, impingement and entrainment
of fisheries resources will be reduced through appropriate design of the intake
screens on the cooling water intake.
Water quality mitigation measures will be implemented to manage
potential impacts from maintenance dredging to within acceptable levels (see Section 7). No fisheries-specific mitigation
measures or compensation are required during operation.
The fisheries impact
assessment has considered the cumulative effects of different activities of
this Project on fisheries resources, habitats and fishing operations. As discussed in Section 7, the cumulative impacts of the various project-specific
construction activities are not predicted to cause unacceptable impacts to
water quality. Consequently,
unacceptable cumulative impacts to fisheries resources are not expected to
occur.
Information from publicly
available sources suggested that the major projects listed in Section 3.6 would coincide with the
construction/ implementation programmes of this Project. These projects either do not have a
marine element or are at more than 1 km from this Project. The only project that may have
cumulative impacts on fisheries with this Project is the Potential Reclamation
at Lung Kwu Tan which may result in loss of fisheries
resources, habitats and fishing grounds.
Detailed information on this concurrent project is not available at the
time of reporting, but its impacts are expected to be minor for fisheries
resources in this part of Hong Kong ([29])
([30]). Considering the small magnitude and
temporary nature of impacts on fisheries from this Project, no unacceptable
cumulative impacts is anticipated.
A discussion of potential
cumulative water quality impacts arising from concurrent projects is provided
in Section 7.11. Since it is unlikely for water quality
mixing zone of this Project to overlap with those of other concurrent projects
in this part of Hong Kong, it is thus concluded that cumulative impacts on
water quality impacts and consequently on fisheries are not predicted to occur.
As no unacceptable impacts
have been predicted to occur during the construction and operation of this
Project, monitoring of fisheries resources during these project phases is not
considered necessary.
A literature review of
baseline information on commercial fisheries resources, habitats and fishing
operations surrounding the waters of the proposed Project has been
undertaken. Results from the review
indicate that fisheries importance of the Assessment Area is low when compared
to other waters of Hong Kong.
Sensitive receivers including spawning grounds, artificial reefs and
oyster production area have been identified; however, the assessment of water
quality impacts demonstrated that these areas will not be unacceptably
affected.
For the land-based
construction of CCGT Unit No.1 and No.2 (if installed), no loss or direct
disturbance to fishing grounds and fisheries habitats is expected. Indirect impacts to fisheries resources
related to perturbations to key water quality parameters from land-based
discharges and runoff are also expected to be insignificant and no
fisheries-specific mitigation measures are required.
During marine construction
of CCGT Unit No.2, direct impacts arising from the proposed marine works
include temporary disturbance to approximately 2 ha of fisheries habitats and
fishing grounds due to minor seabed dredging. Given the small size of the affected
areas and temporary nature of the disturbance, no significant direct impacts
are expected to occur. Potential
impacts of elevated levels of underwater sound as a result of construction
activities are not expected to be unacceptable. Indirect impacts to fisheries resources
related to perturbations to key water quality parameters are also expected to
be insignificant as the predicted changes in water quality are short term,
localised to immediate vicinity of the works area and in compliance with the
corresponding WQOs and assessment criteria. Marine construction works have been
designed to reduce potential impacts on water quality which will, in turn,
reduce impacts on fisheries resources.
No fisheries-specific mitigation measures are required during
construction.
No unacceptable impacts to
fisheries resources, habitats and fishing operations are expected to occur
during the phased operation of CCGT Unit No.1 and No.2. No permanent loss of fisheries habitats
or fishing ground is expected. With
large separation between the proposed cooling water intake and the identified
spawning ground at North Lantau and the absence of significant ichthyoplankton and fish larvae resources in the Assessment
Area, impingement and entrainment of fisheries resources is not
anticipated. Secondary impacts to
fisheries as a result of cooling water discharge and maintenance dredging for
CCGT Unit No.2 are not expected to occur.
Potential obstruction to fishing activities due to dredging works is not
anticipated as it will be conducted adjacent to the artificial seawall of the
BPPS. The seabed temporarily
affected by the dredging works is, therefore, expected to be minimal. No fisheries-specific mitigation
measures are required during operation.
All of the potential
construction and operational fisheries impacts identified are deemed
acceptable.
([1])
Legislative
Council Panel on Food Safety and Environmental Hygiene – Marine Fish Culture in
Hong Kong on 11 June 2013.
Available from:
http://www.legco.gov.hk/yr12-13/english/panels/fseh/papers/fe0611cb2-1284-5-e.pdf
([2]) Sumaila, U. R, Cheung, W. and I. Teh
(2007) Rebuilding Hong Kong’s Marine Fisheries: An Evaluation of Management
Options. Fisheries Centre Research Reports 15
(3). pp.112.
([8])
ERM (1998) Fisheries Resources
and Fishing Operations in Hong Kong Waters, Final Report, for Agriculture and
Fisheries Department.
([12])
Mott MacDonald (2014) Expansion of Hong Kong
International Airport into a Three-Runway System. Approved by EPD under
EIAO on 7 November 2014.
([13])
CEDD (2014 - 2015) Dredging, Management
and Capping of Contaminated Sediment Disposal Facility to the South of The
Brothers. Available at: http://www.sbcmp-monitoring.com.hk/8%20EM&A%20Data/Demersal%20Trawling%20for%20SB%20CMP/Demersal%20Trawling%20Data.html
([14])
CEDD (2012 - 2013) Environmental
Monitoring & Audit for Contaminated Mud Pit V at Sha Chau. Available at: http://www.cmp-monitoring.com.hk/EM&A%20Data/Marine%20Biota%20Monitoring/Marine%20Biota%20Monitoring.html
([16]) Caranx kalla (shrimp scad) spawns in the
early summer (around June) whilst Leiognathus brevirostris (ponyfish) and
croakers were found to be reproductive for a longer period throughout most of
the year from May to December. Some
fish species reported in the spawning grounds, including Platycephalus
indicus (flathead) and Clupanodon
punctatus (gizzard shad), spawn in the late winter/early spring (i.e. February
to April) and a few are known to spawn in January. The spawning period of most of the
crustacean species, including Metapenaeus joyneri was found to be from April to November.
([18]) AFCD (2003) Hong Kong Artificial
Reef Deployment Study. http://www.artificial-reef.net/English/main.htm
([20])
Richardson WJ, Greene CRG, Malme CI, Thomson DH (1995) Marine Mammals and Noise. Academic Press, San Diego, 576 pp
([21]) Species Profiles: Life Histories
and Environmental Requirement (Gulf of Mexico) - Brown Shrimp, US Fish and
Wildlife Service, 1983.
([22]) The Shrimp Fishery of the Gulf of
Mexico – A regional Management Plan, Gulf Coast Research Laboratory, 1977
([23])
References cited in BCL (1994) Marine
Ecology of the Ninepin Islands including Peddicord R
and McFarland V (1996) Effects of suspended dredged material on the commercial
crab, Cancer magister. in PA Krenkel,
J Harrison and JC Burdick (Eds) Dredging and its Environmental
Effects. Proc. Speciality Conference. American Society of Engineers.
([24])
Alabaster JS & Lloyd R (1984) Water
Quality Criteria for Freshwater Fisheries. Butterworths, London.
([25])
City University of Hong Kong (2001). Agreement No. CE
62/98, Consultancy Study on Fisheries and Marine Ecological Criteria for Impact
Assessment, AFCD, Final Report July 2001.
([26])
Fernando Martinez-Andrade and Donald M. Baltz (2003). Coastal
Marine Institute: Marine and Coastal Fishes subject to Impingement by Cooling-Water
Intake Systems in the Northern Gulf of Mexico - An Annotated Bibliography. U.S. Department of the Interior.
([27]) Turnpenny,
A. W. H (1988) Fish impingement at estuarine power stations and its
significance to commercial fishing. Journal
of Fish Biology, Vol. 33, pp. 103-110.
([28])
Water Reuse Association (2011)
Desalination Plant Intakes – Impingement and Entrainment Impacts and Solutions. Available at:
https://www.watereuse.org/wp-content/uploads/2015/10/IE_White_Paper.pdf