9.1.1 The
Fisheries Impact Assessment comprises three major parts: establishment of baseline
conditions, evaluation and assessment of fisheries impact following the
criteria and guidelines of Annexes 9 and 17 of the EIAO-TM, and recommendations
of mitigation measures where necessary.
9.1.2 Key issues
of the Fisheries Impact Assessment, as stipulated in Section 3.4.7.2 of the EIA
Study Brief No. ESB-211/2009, include but not be limited to the following:
Ÿ
Fishing activities;
Ÿ
Fish spawning and nursery
grounds within the assessment area; and
Ÿ
any nearby fish culture zones.
9.1.3 The
assessment covers any potential short and long-term impacts on both capture and
culture fisheries, during the construction and operation phases of the Project.
9.1.4 The
Fisheries Impact Assessment includes the following according to the Study
Brief:
Ÿ
description of the physical
environmental background;
Ÿ
description and quantification
of existing capture and culture fisheries activities;
Ÿ
description and quantification
of existing fisheries resources (e.g. major fisheries products and stocks);
Ÿ
identification of parameters
(e.g. water quality parameters) and areas that will be affected;
Ÿ
identification and evaluation
of any direct and indirect, onsite and offsite impacts on capture fisheries
such as loss or disturbance of fishing grounds, spawning and nursery grounds
and disruption of fishing activities;
Ÿ
identification and evaluation
of any direct and indirect, onsite and offsite impacts on cultures fisheries
such as water quality deterioration in fish culture zone;
Ÿ
recommendations on any
environmental mitigation measures with justification, description of scope and
programme, feasibility as well as staff and financial implications including
those related to subsequent management and maintenance requirements of such
recommendations; and
Ÿ
review of the need for
monitoring and, if necessary, recommendation of monitoring and auditing
programme.
9.2.1 HKSAR
Ordinances and Regulations which are relevant to this study include the
following:
Ÿ
The Environmental Impact
Assessment Ordinance (Cap. 499) and the associated TM;
Ÿ
Fisheries Protection Ordinance
(Cap. 171) and its subsidiary legislation, the Fisheries Protection
Regulations;
Ÿ
Marine Fish Culture Ordinance
(Cap. 353) and its subsidiary legislation; and
Ÿ
Water Pollution Control
Ordinance (Cap. 358) and its subsidiary regulations and statements.
9.3.1 In
accordance with the EIA Study Brief, the Assessment Area generally covers the
North Western Water Control Zone (WCZ) and other areas likely to be impacted by
the Project. Special attention has
been given to the fishing activities and fishing spawning and nursery grounds
within the assessment area.
9.3.2 Existing
information available from relevant studies/surveys regarding the Assessment Area
was reviewed. A review of
Government and private sector reports, independent of Government published
literature and academic studies was undertaken to determine the existing
conditions of fisheries in the assessment area, and to identify practices, areas
and species of potential fisheries importance which may be affected by the
Project. This review included but
was not limited to the following:
Ÿ
Port Survey 2006;
Ÿ
Latest AFCD Departmental Annual
Report (for 2013 – 2014) and departmental website; and
Ÿ
Other relevant reports from
private sectors or Government.
9.3.3 Port
Survey is the most comprehensive territorial-wise fisheries study survey
routinely conducted by AFCD every few years. Different from the approach adopted in
previous Port Surveys in which Hong Kong waters were divided into “Fishing
Areas” of various sizes, a uniform grid was overlaid on Hong Kong’s waters for
Port Survey 2006 and the fisheries related information (e.g. production, vessel
number, catch value) was presented in several categories. In this FIA, the fisheries resources
within the assessment area were evaluated based upon the information from Port
Survey.
9.3.4 AFCD’s
latest Departmental Annual Report (for 2013 - 2014)
and departmental website provide the most updated information on the development
and trend in Hong Kong fisheries.
The latest annual fisheries production is also provided.
9.3.5 Other
studies that are relevant include:
Ÿ
Consultancy Study on Fisheries
and Marine Ecological Criteria for Impact Assessment (CCPC 2001);
Ÿ
Fisheries Resources and Fishing
Operations in Hong Kong Waters (ERM 1998).
9.3.6 The
validity of the information compiled during the literature review has been
assessed before it is adopted into the present FIA study.
9.3.7 Impacts
are assessed in the absence of mitigation. The construction and operational
phases impact of present project on fisheries resources have been assessed
individually in the absent of other concurrent projects, and then accessed
cumulatively, in combination with other existing, committed and proposed
developments.
9.4.1 The
Assessment Area for the fisheries impact assessment generally covers the North
Western Water Control Zone (WCZ) (Figure 9.1)
and other areas likely to be impacted by the Project. Special attention has been given to the
fishing activities and fishing spawning and nursery grounds within the
assessment area (Figure 9.1).
It also includes all areas within 500m from the boundary of the works area,
i.e. Po Chue Tam, Kat Hing Back Street, Shek Tsai Po, Tai O Tai Ping Street,
Lung Tin Estate, Wang Hang Village, Leung Uk Tsuen, San Tsuen, Nam Chung Tsuen
and Fan Kwai Tong.
Criteria to Evaluate Impacts
9.4.2
The significance of fisheries impacts was
evaluated based primarily on the criteria set forth in Annex 9 of the EIAO-TM:
Ÿ
Nature of impact;
Ÿ
Size of affected area;
Ÿ
Loss of fisheries
resources/production;
Ÿ
Destruction and disturbance of
nursery and spawning grounds;
Ÿ
Impact on fishing activity; and
Ÿ
Impact on aquaculture activity.
9.4.3 Impacts
are generally ranked as "minor", "moderate" or
"severe", although in a few cases a ranking of
"insignificant" (less than "minor") may be given. The ranking of a given impact would
vary, based on the criteria listed above.
Wherever possible, significance of impacts is quantified to allow ready
appreciation of relative significance.
Quantification is straight forward for certain types of impact,
particularly loss of fishing ground (usually measured in hectares). Quantification of other types of impact
such as those on fishing and aquaculture activities requires the application of
professional and value judgment.
Such judgment may not be amenable to quantification.
9.4.4 In the
present FIA, impacts on capture fisheries was assessed by the extent of fishing
ground loss during construction and operational phases, and potential decline
in productions due to loss of fishing ground, interferences on fishing
operations, and loss of fisheries resources.
9.4.5 Efforts
would also be made to identify feasible and practicable mitigation measures
required, which might be developed to reduce the severity of any negative
impacts identified. These measures
would be described in terms of scope, programme, feasibility and financial
implications during the construction and operation of the project.
9.4.6 Finally,
the FIA would conclude whether the mitigation measures could bring the negative
impacts caused by the Project and its components within acceptable bounds.
Development of Mitigation Measures
9.4.7 Finally,
the assessment concludes whether the mitigation measures envisaged could limit
the negative impacts of the project and its components to within acceptable
bounds. The acceptability of the
overall residual impacts is determined.
Marine Environments
9.5.1 The
assessment area for fisheries impact assessment is the same as the assessment
area for marine water quality. The
Project Site is located in North Lantau waters, within the western estuarine
zone of Hong Kong waters, to the west of the transitional central and oceanic
eastern waters (Morton & Morton 1983).
The seabed off North Lantau is shallow, usually less than -20m CD. Lying on the east side of the Pearl
River Estuary, north Lantau waters are also heavily influenced by the Pearl
River and have a predominantly sandy substrate.
Sites of Fisheries Importance
9.5.2
Fishing grounds cover most of the open waters in
north Lantau waters, except for shipping fairways and marine exclusion areas. The Project includes both land-based
element and marine-based element (which involves dredging and reclamation) (see
Figure 9.2), and would cause loss of fishing
grounds in North Lantau waters.
9.5.3 Besides
the fishing grounds, the following fisheries resources are located in North
Lantau waters:
Ÿ
Artificial reefs deployed
within Sha Chau and Lung Kwu Chau Marine Park; and those to be deployed within the
proposed Marine Park at the Brothers; and
Ÿ
Important spawning grounds for
commercial fisheries resources in North Lantau waters.
Capture Fisheries
9.5.4 The local
fishing industry makes an important contribution to Hong Kong marine fish
supply. In 2014, it produced an estimated 160,789 tonnes of fisheries
production valued at about $2,530 million. The industry now
consists of some 4500
fishing vessels and 9400
local fishermen working aboard and provides employment in ancillary sectors
servicing the fishing industry, such as fish wholesale and retail marketing,
fuel and fishing gear supply and ice manufacturing (AFCD 2015a).
9.5.5 Detailed
data on recent HKSAR capture fisheries in the fisheries assessment area were
taken from the results of Port Survey 2006. Port Survey is the most comprehensive
territorial-wise fisheries study survey routinely conducted by AFCDevery few
years. The Port Survey consisted of
an interview programme. About 36%
of the local fishing fleet which accounted for all homeports (i.e. places at
which local fishing vessels are based, 38 ports) and vessel types (10 types,
including stern trawler, pair trawler, shrimp trawler, hang trawler, gill
netter, long liner, hand liner, purse seiner, sampan and miscellaneous craft)
was interviewed. During the
interviews, particulars (e.g. vessel length, type and its homeport) of the
fishing vessels were recorded and information about their fishing operations
and fisheries production in Hong Kong waters was collected.
9.5.6 In earlier
Port Surveys, Hong Kong waters were divided into fishing areas of various sizes
and shapes, and these fishing areas were further grouped into 12 sectors.
9.5.7 In the
latest Port Survey in 2006, a uniform grid of 720 ha cell size was overlaid on
Hong Kong waters and the fisheries related information (e.g. production, vessel
number, catch value) was presented in several categories.
9.5.8 Within
HKSAR waters, the highest yields for local fisheries were mainly derived from
the eastern and southern coasts (e.g. the majority of the waters from south Lantau
to Po Toi ) as indicated in the distribution of overall fisheries production on
adult fish (see Figure 9.3), while the western buffer waters
were comparatively less productive.
9.5.9 Within the
North Lantau waters, there are some areas of higher production, including the
waters around the brothers and around Sha Chau and Lung Kwu Chau, But all these
areas are far away from the Project Area and unlikely to be influenced by the
Project given the small scale of reclamation involved.
9.5.10 Although
the fisheries assessment area covers the above mentioned extent, it is
anticipated that the focal area for capture fisheries issues would be the
footprint of the Project itself (including reclamation area). The waters near
Tai O also has higher fish production which is more relevant to the Project.
9.5.11 In
Port Survey, grid cells are categorised into one of the 6 classes, i.e. >
0-50kg/ha; 50-100kg/ha; 100-200kg/ha; 200-400kg/ha; 400-600kg/ha; and
600-1000kg/ha, in accordance with their overall adult fish production. For present study, as reported in the
Port Survey 2006, the catches from the reclamation area is ranked as high in Hong Kong waters
(400-600kg/ha).
9.5.12 Fish
fry production was only concentrated
in the eastern waters (Mirs Bay, Tolo Harbour and Channel, Port Shelter and Po
Toi), with a smaller contribution from the East Lamma Channel (Figure 9.4). However, the results of Port Survey 2006 indicated that fry
collection has become very limited and localized throughout Hong Kong
waters. No fish fry
production was recorded in the entire North Lantau waters including the
Assessment Area.
9.5.13 The
fishing operation in grid cells is also categorized into 6 classes, i.e. >
0-10 vessels; 10-50 vessels; 50-100 vessels; 100-400 vessels; 400-700 vessels;
and 700-1,000 vessels. The
production is mainly contributed by larger fishing vessels (> 15m in length). There were on average 100-400 fishing
vessels operated near the Assessment Area (Figure 9.5). The fishing operation within the
Assessment Area was mainly supported by vessels less than 15m in length. Sampan was the dominant fishing vessel,
followed by Shrimp Trawler and Hang Trawler.
9.5.14 In
Tai O waters, the most common capture fish around the Tai O waters is shrimp
with a high production of 40 – 60kg/ha.
Other common catches in this area include Scad (Carangidae), Rabbit Fish
(Siganidae), Croaker (Sciaenidae) and Mullet (Mugilidae) with a medium
production of 20 – 40kg/ha. The
values of fish production is ranked as high (HK$5,000 – 10,000 per ha
annually), as compared with other fishing grounds in Hong Kong (Figure 9.6).
9.5.15 No
important seasonal spawning area has been identified within the Project
Site. Within the North Western WCZ,
there is an important spawning area for commercial fisheries resources located
approximately 8 km to the northeast of Tai O (the North Lantau waters between
the Brothers Islands and Lung Kwu Chau) (ERM 1998). The spawning area is approximately 10km
(from the Brothers Islands to Lung Kwu Chau) x 5km (from Castle Peak to the
Northeast corner of Airport Island).
Major species included Pony fish Leiognathus
brevirostris, Sea bass Lateolabrax
japonicus, and Gizzard shad Clupanodon
punctatus.
Culture Fisheries
9.5.16 In Hong Kong, aquaculture includes marine
fish culture, pond fish culture and oyster culture. In 2014 production from the
aquaculture sector was 3,377 tonnes value at $169 million which was 2% in
weight and 6% in value of the total fisheries production (AFCD 2015b).
9.5.17 Though
there were some ponds in Tai O area as indicated in the habitat maps for
ecology chapter, there were no sign of pond fish culture observed in those
ponds. Even these ponds would have been used for fish culture, they should be
abandoned for a prolonged period.
And the land-based element for the Project is of very small scale and
mainly conducted in urbanised area, it is thus considered that pond fish
culture is not an issue for the present FIA. As the oyster farming sites are far away
(in Deep Bay area), the culture fisheries would only focus on marine fish
culture. Marine fish culture
In Hong Kong involves rearing of marine fish from fry or fingerlings to
marketable size in cages suspended from floating rafts usually in sheltered
coastal areas. Common species under
culture include green grouper, brown-spotted grouper, giant grouper, Russell's
snapper, mangrove snapper, goldlined seabream, star snapper and red drum (AFCD
2013b).
9.5.18 Marine
fish culture is protected and regulated by the Marine Fish Culture Ordinance
(Cap. 353), which requires all marine fish culture activity to operate under
licence in designated fish culture zones.
Currently, there are 26 fish culture zones (Figure 9.7) occupying a
total sea area of 209 ha with some 968 licensed operators. In 2014, the production from local
marine fish culture was 1,255 tonnes (of value HK$115
million), constituting 6% of the local demand for live marine fish
(AFCD 2014b).
9.5.19 Water
quality within Marine FCZs is regulated under the WPCO and its supporting
regulations and statements. Within
Fish Culture Subzones, the dissolved oxygen level should not be less than 5
mg/L for 90% of the sampling occasions during the year; values should be
calculated as water column average (arithmetic mean of at least 3 measurements
at 1 metre below surface, mid-depth and 1 metre above seabed). In addition, the concentration of
dissolved oxygen should not be less than 2 mg/L per litre within 2 metres of
the seabed for 90% of the sampling occasions during the year, and the annual
geometric mean of E. coli should not exceed 610/100 ml.
9.5.20 There
are no Fish Culture Zones (FCZs) within the footprint for the Project or in the
vicinity. Of the 26 gazetted FCZs
zones in Hong Kong, none occur within the fisheries assessment area (North
Western WCZ). The nearest FCZ is
the Cheung Sha Wan Fish Culture Zone, which is approximately 16 km to the
southeast of the Project Site and sheltered from the Project Site by the
landmass of Lantau Island. Ma Wan Fish Culture Zone is relatively closer to the
North Western WCZ and is located about 22 km to the east of the Project Site.
Artificial Reefs
9.5.21 Artificial
reefs (AR), a fisheries resource enhancement measure, have been deployed near the
northeast corner of Airport Island within Marine Exclusion Zone 3 and at Sha
Chau and Lung Kwu Chau Marine Park.
Though primarily postulated as feeding stations for Chinese White
Dolphin, these artificial reefs also help to enhance habitat quality and marine
resources, including fisheries resources.
Both ARs were deployed in 2000.
The ARs at Airport Island is about 9 km
from the Project Site, while the ARs in the Marine Park are about 11 km from
the Project Site. The ARs in Marine Exclusion Zone 3 are indeed close to the on-going
HKBCF construction site and are anticipated to be impacted by the HKBCF
construction work, as such replacement ARs are proposed to be deployed as
mitigation in the HKBCF EIA (ARUP 2009). Therefore, the ARs in Marine
Exclusion Zone 3 are not considered as sites of fisheries importance in the present
FIA.
9.5.22 Besides
the above existing ARs, new ARs are also proposed in the Proposed Marine Park
at the Brothers which is a mitigation measure for marine habitat loss due to the HKBCF reclamation. The
authority made a firm commitment to seek the designation of a marine park at
the Brothers, to mitigate the habitat loss of Chinese White Dolphins. As it was predicted in the HZMB EIA
that impacts on the ARs were
expected, replacement ARs
will be deployed as a mitigation
measure, probably at the proposed The Brothers Marine Park, and will still be more than 10 km away from the Project
Site. The detailed study for the proposed Marine Park and the new ARs
are still ongoing, but the preliminary boundary of the proposed Marine Park has
been proposed. In accordance with the HKBCF EIA, the new ARs would be at least
three times the volume of the existing ARs inside the Marine Exclusion Zone,
and thus should be over 3,600m3.
Fisheries Sensitive Receivers
9.5.23 Identified
fisheries sensitive receivers include the following:
Ÿ
Fishing ground around Tai O
waters;
Ÿ
Nursery ground for commercial fisheries resources in South Lantau;
Ÿ
Artificial reefs deployed
within Sha Chau and Lung Kwu Chau Marine Park; and those to be deployed within
the proposed Marine Park at the Brothers; and
Ÿ
Important spawning grounds for
commercial fisheries resources in North Lantau waters.
Identification of Data Gap
9.5.24 This
fisheries impact assessment aims at providing sufficient and accurate data to
allow complete and objective prediction and evaluation of the potential
fisheries impacts. Desk-top study
has produced a complete picture of the fisheries resources of the assessment
area. The Port Survey and the
consultancy study on fisheries resources and fishing operations have
provided information sufficient for fisheries impact assessments and were
considered adequate for assessment of impacts of the present Project. No data gap in fisheries baseline was
identified in terms of fisheries assessment.
General Environmental Impacts
9.6.1 The
assessment and sensitive receivers largely focused in the North Lantau waters
where the Project is located. For
the fisheries resources, the water quality assessment results would be able to
demonstrate whether they are subject to indirect impacts from the Project.
9.6.2 The key
impact sources associated with the Project with respect to fisheries included
the loss of sea areas and water quality impacts from the reclamations and the
submarine outfall.
9.6.3 Fully-dredge
with the use of closed grab dredgers is a traditional way to construct
submarine outfall. The seabed is
dredged to the required depth for placing the outfall pipes and the pipes
protection materials. Under this
option, the outfall could be designed to its shortest length of 130m in order
to minimize the associated environmental impacts during both the construction
and operation stage. Proper
protections on outfall pipes with armoured rock could be provided to enhance
the durability of pipelines.
Measures such as silt curtains could be provided around the seabed
excavation for the outfall construction so as to contain marine sediment and
minimise water quality impact.
9.6.4 Potential
sources of impact during the construction phase include:
Ÿ
Temporary and permanent loss of
fishing grounds;
Ÿ
Disturbance of fishing
operation;
Ÿ
Marine water quality impact
caused by construction run-off, dredging and filling, and associated impacts on
fisheries resources.
9.6.5
Potential sources of impact during the operation
phase include:
Ÿ
Changes in water quality caused
by normal discharge of treated sewage from outfall and emergency discharge of
untreated sewage from STW and/or the two proposed SPSs;
Ÿ
Changes to local hydrodynamic
regime and consequential water quality impacts caused by the reclamations;
Ÿ
Marine water quality
degradation caused by activities on the reclamations;
Ÿ
Restrictions on fishing
operation.
Construction Phase – Direct Impacts
9.6.6 Reclamation
comprising a seawall and stone fill reclamation, adjacent to, and at the west
of the existing STW site. It would cause a net loss of 0.26 ha of seabed and water column, and thus a
permanent loss of fishing ground.
The works areas for both the reclamation and the outfall construction
would also constitute a temporary fishing ground loss of 1.1 ha as the works areas would
not be available for fishing operations during the construction phase.
9.6.7 When
compared with the 1,651km2 of Hong Kong’s total marine waters (EPD
2005) which is mostly available for fishing, the permanent (0.26 ha) loss of fishing ground and
temporary fishing ground loss (1.1 ha) caused by the Project is considered to
be of insignificant proportion.
Moreover, the proposed reclamation area is located near the seashore,
fishing activities are unlikely to occur at the loss area.
9.6.8 Although
the sea areas of the temporary and permanent losses are of high production
output, the magnitude of the impact would be very low due to the very small
sizes of reclamation and works areas.
For the present project, the reclamation area is very small, if based
upon the production of Tai O waters (production of the grid cell is 400 –
600kg/ha), the maximum loss from the 0.26 ha would be only 156kg per year. This impact is therefore considered Insignificant
and hence mitigation is not required.
Construction Phase – Indirect Impacts (Water quality impact)
9.6.9 The major
potential activities that could cause water quality impacts during the
construction phase of the Project include:
Ÿ
Marine traffic (e.g. working
barges);
Ÿ
Dredging;
Ÿ
Seawall construction;
Ÿ
Reclamation filling behind
seawall;
Ÿ
Construction site runoff; and
Ÿ
Wastewater from construction
activities.
9.6.10 Besides
these activities, sewage generated by the workforce and accidental spillage of
works site chemicals might also cause water quality impacts but would be, if
any, at an extremely small scale. This impact is therefore considered Insignificant
and hence mitigation is not required.
9.6.11 During
construction phase, dredging works are required to remove the soft marine
deposit underneath the foundation of seawall and reclamation area. The proposed
seawall shall comprise pre-casted seawall blocks and suitable back filling
material at the boundary of reclamation area. In fact, dredging and filling
works for the reclamation and submarine outfall are both potential sources of
suspended solids and the associated water quality deteriorations such as
reduction in dissolved oxygen. In
accordance with the water quality assessment results, the allowable SS increase
would be exceeded the allowable limit (i.e. less than 30% of the ambient
concentration at all times referring to the WQO standard of SS, or 4.3 mg/L in
this case) within 550m from the dredging site if no mitigation measures are taken
during the dredging activity. The
potential impact is ranked as minor and appropriate mitigation measures
to the dredging activities will be implemented to minimise the potential
impact.
9.6.12 A
dredging rate of 62.5m3/hour is recommended. Reduction in dredging
rate will decrease the dispersion of suspended solids which in turn would
prolong the dredging duration. It is estimated that the dredging duration would
be less than 2 months with the dredging rate of 62.5m3/hour.
Subsequently, the sediment release rate will be decreased to around 0.313 kg/s.
Cage type silt curtains will also be provided during the dredging. Suspended
solids will be reduced by 75% with the incorporation of silt curtain.
9.6.13 With
the implementation of mitigation measures including using closed grab dredges,
reducing the dredging rate and installing silt curtains, the elevation of
suspended solids concentration will greatly decrease compared to those without
mitigation measure (see Table 5.14 in water quality chapter), and the SS only
fails the compliance of the WQO standard (i.e. 4.3mg/L) within 150m area, which
is considered acceptable.
9.6.14 Western
Hong Kong waters are in estuarine conditions and characterized by high
background levels of suspended solids due to the proximity to the Pearl River
estuary. Marine fauna including fisheries species in western waters are
inhabiting an environment subject to estuarine influences, and thus should be
able to adapt to a high SS environment, and the fish has developed some
adaptation behaviour (e.g. clearing of gills, swimming to clear areas) to
tolerate such environment.
Therefore, they are not expected to be impacted by the small-scale SS
increase caused by the Project.
9.6.15 The
dredged marine sediment may contain organics materials and lead to a decrease
in dissolved oxygen. The water quality results indicated that the DO is still
in compliance with the WQO standard (4mg/L) even without mitigation. With the
implementation of above-mentioned mitigation measures to the dredging
activities, the DO depletion will be further reduced. Thus, no significant adverse impact on
DO is anticipated.
9.6.16 Resuspension
of seabed sediment might potentially incur the release of contaminants, if any,
into the seawater. If contaminants are present in the seawater, they may
eventually be taken up into food chains that are linked to fisheries resources,
and thus affected fisheries. Water
quality assessment has been conducted for the potential release of contaminants
during sediment dredging (Section
5.6.18). Results indicate that the impacts would comply with
statutory requirements.
9.6.17 The
potential water quality impacts due to land works including site runoff, sewage
from workforce and wastewater from various construction activities, and
accidental spillage would be controlled through the implementation of suitable
mitigation measures, including temporary drainage system, chemical toilets, etc
(See Section 5.6.1 – 5.6.7).
9.6.18 There
is also an increased risk of small-scale oil or chemical (construction works
solvent) spills from vessels due to the increased number of vessels working in
the area. Because of the small volumes of such materials involved, this risk is
considered insignificant.
9.6.19 The
impact from water quality deterioration on fisheries resources and fisheries
sensitive receivers is thus ranked as Minor
and specific mitigation is not required other than the water quality
measures.
Construction Phase – Indirect Impacts (Disturbance on Fishing Operation)
9.6.20 In
the vicinity of the reclamation areas, fishing operation might be disturbed by
the increased marine traffic of working vessels for the Project. The
disturbance impact however would be temporary. As the majority of fishing vessels
operating in the vicinity are small-sized vessels, these small vessels would
have higher flexibility in their operations and less sensitive to disturbance
from marine traffic. Given the
small size reclamation area, this temporary impact would be Minor. No mitigation is required.
Operational Phase – Direct Impacts
9.6.21 No
direct impact is expected to arise during operational phase under the normal
operation of the proposed sewerage works.
Operational Phase – Indirect Impacts
9.6.22 The
operation of SPS with associated gravity sewers will connect unsewered areas to
sewer mains. The sewer mains will
lead untreated or partially treated sewage to Tai O STW, and that treated
effluent will then be discharged into the North Western WCZ. In other words, the total pollutant load
to the North Western WCZ is expected to decrease through the decrease in
untreated sewage discharge.
Potential improvements to water quality would therefore be achieved and
that fisheries resources would receive beneficial impact. The near-field
modelling water quality results in Section 5.6 indicated that during the
operation phase, the water quality parameters at a distance of 10 ~ 11m from
the outfall (i.e. the edge of the initial mixing zone) would generally meet the
WQO standard, with a marginal (i.e. 0.01 mg/L) non-compliance at TIN in wet
season. However, the background TIN value is relatively high (0.44mg/L)
compared to WQO standard (0.5mg/L), and this exceedance only occurs under one
extreme condition. The compliance of the TIN WQO was achieved in all other
scenarios. Therefore, no adverse impact from TIN increment is anticipated. For
the fisheries resources near Tai O, as compliance of WQO on the concentrations
of concerned pollutants were observed at the edge of initial mixing zone, no
adverse water quality impact is anticipated, especially outside of the initial
mixing zone. The initial mixing zone was also predicted to be localized in a
small scale. Thus, it is expected that the no significant adverse impact would occur to the fisheries
resources in the vicinity of Tai O.
9.6.23 According
to the Water Quality Chapter, a time-series comparison of the magnitude and
direction of tidal flow currents near the project area for the pre- and post-
reclamation scenarios was conducted. The comparison shows that the hydrodynamic
change due to the reclamation is not significant.
9.6.24 In
case of the failure of the duty and standby submarine outfalls, treated
effluent would be diverted to the emergency outfall for discharge. Furthermore,
raw sewage may be diverted to the submarine outfall or the emergency outfall
for discharge in the case of temporary failure of treatment units. Though these
emergency events would be rare, the worst case of discharge via emergency
outfall was evaluated in the water quality assessment and presented in Section
5.6. For most of the water quality parameters, they could meet the WQO standard
after 100m distance from the
release point. The exceptions are TIN and UIA which require longer distances
from 1000m to 1500m.
There will also be potential adverse impact on water quality associated with
sewage overflow from the SPS during pump failure, power supply failure, and
damage to pressure main or flooding.
Nevertheless, with the precautionary measures discussed in the Water
Quality section, such as provision of standby power to secure electricity
supply, and provision of standby pumps etc., the possibility of sewage overflow
would be extremely remote.
Therefore, potential adverse impacts on fisheries due to sewage overflow
are considered to be Insignificant.
9.6.25 Construction
and Operational phase impacts on fisheries are summarised in Table 9.1
above. There are no insurmountable impacts
on fisheries from the construction and operation of the Project. There would also be no unacceptable
impact during the construction and operation phases on the fisheries sensitive
receivers within the assessment area.
Overall Cumulative Impacts with other
developments
9.6.26 As
stipulated in Section 4.3.3 of EIAO-TM, the assessment of cumulative
environmental impacts is required in three circumstances:
Ÿ
the impacts arising from the
project are predicted to extend beyond the boundaries of the project or over a
long period of time;
Ÿ
there may be interactions
between the environmental impacts of the project, affecting the sum total of
its environmental impacts; or
Ÿ
there may be interactions
between the environmental impacts of the project and those of other developments,
and this could result in accumulation of impacts, which would affect the total
effect.
9.6.27 The
potential interactions between the construction and operational phase impacts
of the Project were examined in previous sections. This section examines whether there
might be interactions between the environmental impacts of the Project and
those of other developments whose construction or operational phases would
overlap with the present project, thereby resulting in cumulative impacts whose
effects would exceed in severity those of the various projects taken
individually. Nearby projects that
would have potential cumulative fisheries impacts (water quality) are shown in Table 9.2.
9.6.28 The
projects are all land-based construction, potential indirect impact may affect
water quality and subsequent fishery resources. However, no accumulation effect is
expected if proper mitigation measures such as good site practice are employed
by those projects.
Table 9.2 : Concurrent Projects with
Implications on Fisheries
|
Proposed Development
|
Nature of the projects
|
Impacts to be Considered
|
Seabed loss
|
Schedule
|
|
Construction
|
Operation
|
|
Natural Terrain Hazard Mitigation Works” undertaken
by CEDD/GEO
|
Natural terrain hazard mitigation works
|
P
|
|
No
|
Commence in June 2015, for completion in December
2017
|
|
Water Supply from Tung Chung to Tai O
|
Construction of water mains
|
P
|
|
No
|
The design and construction of this project is
suspended at the current stage
|
|
Replacement and Rehabilitation of Water Mains Stage
3, Mains On Hong Kong and Islands – Investigation, Design and Construction
|
Construction of water mains
|
P
|
|
No
|
Mid 2012
|
|
Replacement and Rehabilitation of Water
Mains Stage 4, Mains On Hong Kong and Islands – Investigation, Design and
Construction
|
Construction of water mains
|
P
|
|
No
|
Mid 2012 – Mid 2016
|
9.7.1 The
following paragraphs identify feasible and practicable mitigation measures for
the construction and operational and phases to reduce the severity of any
negative impacts identified in the previous sections.
Construction phase – Direct Impacts
9.7.2 There
would be permanent loss of fishing ground due to the reclamation, but the
impact is considered Insignificant.
Mitigation is thus not required.
On the other hand, adoption of sloping rip-rap seawalls to provide more
microhabitats for fish fry can be considered. Artificial seawalls in the form
as inclined rubble-mount are considered of some fisheries value due to the
artificial reef like function in some approved EIA studies such as HZMB-HKBCF
(ARUP 2009).
Construction phase – Indirect Impacts
9.7.3 Mitigation
measures for water quality would be required. Any significant changes in
water quality or turbidity (re-suspension of sediments) should be avoided. This could be mitigated through
construction methods. This includes
measures such as using closed-grab dredging, and using cage type silt curtains
around the work areas. To conclude,
the number of concurrent dredging/filling work fronts should be limited,
closed-grab dredging and silt curtains should be used, and the seawall should
be constructed prior to the filling works.
9.7.4 Good Site
Practices: – The integrity and effectiveness of all cage type silt curtains
should be regularly inspected.
Effluent monitoring should be incorporated to make sure that the
discharged effluent from construction sites meets the effluent discharge
guidelines.
9.7.5 Strict
enforcement on no-dumping: – Restrictions prohibiting dumping of rubbish, food,
oil, or chemicals should be strictly enforced. This should also be covered in the
contractor briefings.
9.7.6 Spill
response plan - There will also be a spill response plan if vessels operating
in the works areas will be transporting oil or other hazardous chemicals. The
oil spill response plan will have specific provisions for protecting marine
ecological resources. Given these
measures, the marine ecosystem as well as fisheries resources in the area would
be protected.
Operational phase
9.7.7 No
fisheries specific mitigation measure is required for the operation phase of
the Project.
9.7.8 Mitigation
measures for the construction and operational impacts are summarised in Table 9.3 below:
Table 9.3 : Mitigation Measures for Construction Phase
|
Impacts
|
Mitigation Measures and Effects
|
|
Water quality
|
Cage type silt curtains, closed-grab
dredging
|
|
Minimised dredging works; filling after
completion of seawall; limit the works fronts; using closed grab; employing
silt curtains.
|
|
Good site practices
|
|
No dumping policy
|
|
Spill response plan
|
9.7.9 The
implementation arrangement, resources requirement, subsequent management and
maintenance of the above proposed mitigation measures will be detailed in
separated contracts and covered by the EMIS.
9.8.1 The
Project will result in loss of fishing ground. However, the loss of fishing ground is
relatively small. The loss will
result in an estimated reduction in total adult fish production of 156 kg per
year in maximum. Moreover, the proposed reclamation area is located near the
seashore, fishing activities are unlikely to occur at the loss area. Therefore
the loss of fishing ground is not expected to have a significant negative
impact on capture fisheries.
Residual impacts of loss of fishing ground are acceptable.
9.8.2 Provided
that the mitigation measures for water quality are implemented, no significant
residual impacts are predicted during the construction and operation phases on
capture fisheries or mariculture.
9.9.1 There will
be monitoring and auditing for marine water quality during construction of the
Project. A monitoring and audit
programme aims to ensure that the released SS concentrations from the dredging
activities would not adversely affect the sensitive receivers. This monitoring
programme would be used to assess the effectiveness of mitigation measures
during construction. No specific
fisheries EM&A programme would thus be required during the construction and
operation phases of the project.
9.10.1
The reclamation would cause a net loss of 0.26
ha in sea area (seabed and water column) in North Lantau waters. When compared with the 1,651 km2
of Hong Kong’s total marine waters which is mostly available for fishing, the
fishing ground loss caused by the Project is considered to be very small. This loss would therefore be Insignificant. Besides the permanent loss, the project
aims to improve the coastal water quality to the northwest of Tai O by
provision and upgrading the sewage treatment facilities, which may have
potential benefits for fishery resources in the long term. Besides the
water quality mitigation measures, no other mitigation measures for fisheries
are required.
Ÿ
Agriculture Fisheries and
Conservation Department (AFCD) 2015a. Capture
Fisheries. In: http://www.afcd.gov.hk/english/fisheries/fish_cap/fish_cap.html
(last revision 11 March 2015)
Ÿ
Agriculture Fisheries and
Conservation Department (AFCD) 2015b. Marine fish
culture, pond fish culture and oyster culture. In: http://www.afcd.gov.hk/english/fisheries/fish_aqu/fish_aqu_mpo/fish_aqu_mpo.html
(last revision 17 March 2015)
Ÿ
ARUP 2009. Hong Kong - Zhuhai - Macao
Bridge Hong Kong Boundary Crossing Facilities: Environmental Impact Assessment
– Final Report.
Ÿ
CCPC 2001. Agreement No. CE
62/98 - Consultancy Study on Fisheries and Marine Ecological Criteria for
Impact Assessment. Prepared for Agriculture, Fisheries and Conservation
Department, HKSAR Government.
Ÿ
EPD 2005. 20 years of marine
water quality monitoring in Hong Kong.
Ÿ
ERM 1998. Fisheries Resources
and Fishing Operations in Hong Kong Waters.
Ÿ
ERM 2000. Study on Sustainable
Development for the 21st Century: Environmental Baseline Survey on Terrestrial
Habitat Mapping and Ranking Based on Conservation Value. Final Report to the
Planning Department.
Ÿ
Morton, R & B. Morton 1983.
Seashore Ecology of Hong Kong. Hong Kong University Press.