9.1.1
This section presents the
assessment on the fisheries impacts associated with the upgrading of the Cheung
Chau STW and Pak She SPS and the sewers works of the Project. This assessment comprises three major parts:
establishment of baseline conditions, evaluation and assessment of fisheries
impact Appropriate mitigation measures were identified, where necessary, to
mitigate the potential impacts.
9.1.2
This assessment has based on
the criteria and guidelines for evaluation and assessment of fisheries impacts
as stated in Annexes 9 and 17 of the EIAO-TM and has covered the scope outlined
in Section 3.4.7 of the EIA Study Brief.
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
associated subsidiary legislation; and
Ÿ
Water Pollution Control Ordinance (Cap. 358) and
its supporting regulations and statements.
9.3.1
In accordance with the EIA
study brief, the assessment area generally covers the Southern Water Control
Zone (WCZ) and includes any 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 and the Cheung Sha Wan Fish Culture Zone.
9.4.1
Existing information available
from relevant studies/surveys regarding the Assessment Area was reviewed. A review of Government and private
sector reports, independent 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
Agriculture, Fisheries and Conservation
Department (AFCD) latest annual report 2009/2010 and website; and
Ÿ
Other relevant reports from
private sectors or Government.
9.4.2
Port Survey is the most
comprehensive fisheries study 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 of 720 ha cell size 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. The fisheries resources
within the assessment area were evaluated based upon the information from Port
Survey. The results of Port Survey 2006 are available on AFCD website.
9.4.3
AFCD’s annual report and
website provide the most updated information on the development and trend in
Hong Kong fisheries. The latest
annual fisheries production is also provided.
9.4.4
Based on the review results,
the assessment identified data gap and determine if there is any need for field
surveys. If field surveys are
considered necessary, the assessment would recommend appropriate methodology,
duration and timing for the field surveys.
9.4.5
Impacts are assessed in the
absence of mitigation. The
construction and operational phase impacts on fisheries resources have been
assessed individually, then cumulatively, in combination with other existing, committed
and proposed developments.
9.5.1
A detailed description of the
physical marine conditions is presented in the Water Quality Assessment and
the key aspects are summarized below.
The assessment area of present Project is located in the Southern Water
Control Zone, which stretches from Hong Kong Island south to Lantau Island and
faces the South China Sea (EPD 2010).
9.5.2
In 2010, the Southern WCZ
attained an overall 67% compliance with the WQOs. Although full compliance with
the WQOs for NH3 and E. coli was achieved in 2010, there was a
decrease in total inorganic nitrogen (TIN) compliance rate due to the higher
TIN levels recorded mainly in the summer months from June to September. This
could be related to the heavy rainfalls recorded in the Pearl River Delta area
in the same period (EPD 2010).
9.5.3
In Hong Kong, the commercial
marine fishing industry is divided into capture and culture fisheries. Further
details of these resources are discussed below.
Capture Fisheries
9.5.4
In 2012, the fishing
industry produced an estimated 155,230 tonnes of fisheries produce valued at
about $2 317 million. The industry
consists of some 4 000 fishing vessels and 8 800 local fishermen (AFCD 2013a).
9.5.5
The top 10 families/groups captured
in Hong Kong were Carangidae (e.g. Scad), mixed shrimp, Siganidae (e.g.
rabbitfish), mixed squid, Sciaenidae (e.g. Croaker), mixed crab, Mugilidae
(e.g. Mullet), Clupeidae (e.g. Sardine), Sparidae (e.g. Seabream) and Engraulidae (e.g., Anchovy) (AFCD 2013a).
9.5.6
AFCD Port Survey provides the
most comprehensive information on capture fisheries in Hong Kong waters,
including fishing operation and fisheries production (adult fish and fish fry).
9.5.7
The Port Survey consisted of an
interview programme. About 36% of
the local fishing fleet which accounted for all homeports (places at which
local fishing vessels are based) and vessel types was interviewed. Particulars
such as 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 during the interviews. Cheung Chau is one of the main homeports
in Hong Kong (AFCD 2013a).
9.5.8
According to the Port Survey
2006, the water bodies near Po Toi, Ninepin Group and Tap Mun have the highest
fisheries production (adult fish) (600-1000 kg/ha) (Figure 9.1). The overall adult
fish production surrounding Cheung Chau was comparatively lower and at medium
level, with two northern grids of Cheung Chau at 200-400 kg/ha and the two
southern grids at 400-600 kg/ha.
Fisheries production from vessels exceeding 15m in length was 100-200
kg/ha and 200-400kg/ha in the northern and southern waters of Cheung Chau,
respectively; while the production from vessels below 15m were lower (from
50-100 kg/ha to 100-200kg/ha) than the production from vessels larger than
15m. It should be noted that the
vessels exceeding 15m usually include many trawlers. As a ban on trawling
activities in Hong Kong waters has been in effective from 31 December 2012,
those trawlers would not able to operate in the waters surrounding Cheung Chau
anymore. The fisheries production from vessels over 15m, which contributed more
for the total fisheries production in the waters around Cheung Chau, would
decrease, and so would the total fisheries production. It is thus expected that
the current fisheries production in the waters surrounding Cheung Chau would be
much lower than those reported in the Port Survey 2006.
9.5.9
In Hong Kong, fish fry
production has become very limited throughout Hong Kong waters. This fisheries
activity was only operated in a few locations in the eastern Hong Kong waters (Figure 9.2) (AFCD 2013a). There was no significant fish fry collection in the entire
Fisheries Assessment Area. .
9.5.10
The value of fisheries
production in the waters to the west of Cheung Chau was regarded as moderate
value (HK$2,000-HK$5,000 /ha/yr).
Waters to the east and to the south of Cheung Chau were generally
higher, having moderate - high
value (HK$5,000-HK$10,000 /ha/yr) (Figure 9.3)
(AFCD 2013a).
Marine Fish Culture
9.5.11
In Hong
Kong, aquaculture includes marine fish culture, pond fish culture and oyster
culture. In 2012 production from the aquaculture sector was 3,697 tonnes value
at $181 million which was 2% in weight and 7% in value of the total fisheries
production (AFCD 2013b).
9.5.12
Marine Fish culture involves
rearing of marine fish from fry or fingerlings to marketable size in cages
suspended by floating rafts usually in sheltered coastal areas. The species cultured changed gradually
over the recent years depending on the availability of imported fry mainly from
the Mainland, Thailand, Philippines or Indonesia. 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).
9.5.13
There are four Fish Culture
Zones (FCZ) within the Southern WCZ study area. The two FCZ located in Sok Kwu Wan and
Lo Tik Wan in eastern Lamma Island and the FCZ located in Po Toi are too remote
(over 10 km) from the Project Area and are not expected to be impacted by the
Project. The closest FCZ is located
at Cheung Sha Wan near Chi Ma Wan, which is about 2.7 km from the Project Site
(Figure
9.4) (AFCD 2013b).
9.5.14
The latest information (31 Jan
2009) from AFCD indicates that the Cheung Sha Wan FCZ consists of 134 licensed
rafts with a total licensed area of 20,302 m2 (9.4% of total
gazetted area in HK). No figure is available on fish production at this FCZ,
although the estimated total local production of marine culture fish in 2008
was about 1,370 tonnes valued at HK$82 million (B & V 2009).
Spawning and Nursery Areas
9.5.15
The Southern Hong Kong waters
(including South Lantau and Cheung Chau) were previously identified in 1998 as
important fisheries spawning ground for high value commercial species (Figure 9.5). These waters were
also identified as important nursery ground for a number of commercial juvenile
fish and crustacean species (ERM 1998, 2006) (Figure 9.6).
9.5.16
In summary, there are some
fisheries resources in the waters surrounding Cheung Chau, including fishing
grounds, fisheries species spawning and nursery grounds, and Fish Culture
Zone. The Cheung Sha Wan FCZ
(represented by WER F1) and the fisheries species spawning and nursery grounds
as well as the fishing grounds (represented by WSR S1, S2, and S3) are
considered as fisheries sensitive receivers when assessing the potential
impacts from the Project, particularly potential water quality impact. Assessment below will address the
potential impacts on these fisheries resources.
Construction Phase - Direct Impacts
9.6.1
The proposed Project includes
sewers works and upgrading of the existing Cheung Chau STW and Pak She
SPS. All works would be land-
based, and would involve 1) the laying of sewers along and underneath existing
roads and footpaths, and 2) the construction / upgrading of the existing Cheung
Chau STW and Pak She SPS (subject to the final design) within developed area. The alignments and footprints of all
elements under this Project would be land-based, and no marine components such
as submarine outfall are included.
As such no works would be carried out in the marine or intertidal
environment.
9.6.2
No direct impacts have been
identified during the construction phase.
No loss of fishing ground as well as spawning and nursery area of fishes
is expected. The impacts of
construction and operation phases were evaluated in Table 9.1.
Construction Phase - Indirect Impacts
9.6.3
All the construction works are
land-based and no works will be carried out in the marine or intertidal
environment. If there were no
control on the construction sites, increased sedimentation due to construction
site runoff might lead to a short-term increase in suspended solid, which may
be gradually settled in the vicinity of the coastal area. It should be noted that the
concentration of suspended sediment fluxes naturally in the marine environment,
and fish has developed some adaptative behaviours (e.g. clearing of gills,
swimming to clear area) to tolerate changes in suspended solid and polluted
drainage water. The nearest Fish
Culture Zone to Cheung Chau is Cheung Sha Wan FCZ which is about 2.5 km to the
north of the northern end of Cheung Chau and approximately 4km from the Project
Area. It is also sheltered from
Cheung Chau by a headland on Chi Ma Wan Peninsula. Even if there were sediments from site
runoff, it is very unlikely that they would disperse to this FCZ.
9.6.4
It should be noted that all
effluents from the construction sites, including the site runoff, are
controlled under the WPCO. The
relevant water pollution control and mitigation measures are required to be
implemented, and no polluting effluents are allowed to enter into the marine
waters. With the implementation of
good site practice and precautionary measures, potential impact due to site
effluents is avoided, and thus adverse impact on fishery resources is not
anticipated.
Operation Phase - Direct Impacts
9.6.5
No direct impact is expected to
arise during operation phase under the normal operation of the proposed
sewerage works.
Operation Phase - Indirect Impacts
Indirect Impact - Water Quality Changes (Normal
Operation)
9.6.6
Currently there is no public
sewerage system for most of the village houses in Cheung Chau. Sewage from these village houses is
mainly treated in septic tanks, sewage and greywater generated from some of the
village houses is even directly discharged into surface drainage system. Besides, there is existing combined sewerage
and drainage system in Cheung Chau. Sewage would contaminate the stormwater
and discharge into the sea without being treated. The Project aims at upgrading and
expanding the sewage collection, treatment and disposal facilities to cover
unsewered areas and to cope with future developments. Moreover, separation of the existing
combined sewerage system is to be included in the design as far as
possible. With the implementation
of the Project, public sewers will be provided to all village houses as far as
possible. Combined sewerage system
will be separated as far as possible.
Moreover, the sewage treatment level will be upgraded from primary
treatment to secondary treatment.
Contamination to the receiving water will be reduced and hence improve
the water quality of Cheung Chau as well as the Southern WCZ., hence resulting
in better habitat quality for fisheries resources, including fishing ground,
spawning ground and nursery ground for commercial species, and the Cheung Sha
Wan FCZ.
9.6.7
The water quality parameters
(including annual 90% depth-average DO, 90% bottom DO, TIN, SS, UIA, E.coli and BOD5) in the
identified WSRs during the baseline conditions (i.e. the operation of the
existing STW) and the normal operation of the upgrade STW were presented in Section 5.6 and compared. It was found that incompliance of the
TIN will occur in both the dry and wet seasons under the baseline condition as
well as the normal operation. But
the incremental difference between the two scenarios indicated improvements
(increase of DO, and reductions in TIN, UIA, SS, and BOD5 and E.coli) in both dry and wet
seasons. Upon completion of the
upgrading works, a relative improvement of water quality is expected to occur
to marine waters near the Cheung Chau area, especially near the Cheung Chau Wan
area. Reductions in concentrations
of a number of water quality parameters including DO, TIN, UIA, SS, BOD5
and E.coli were predicted. In Cheung Sha Wan Fish Culture Zone (WSR
F1), there will be a reduction of E.coli
(-3 count/100ml) during the wet season (see Table
5.16). No adverse water
quality impact is anticipated under the normal operating conditions of the
upgraded Cheung Chau STW. For the
spawning and nursery grounds, there will be a reduction in E.coli in both dry season (-28 count/100ml, see Table 5.15), and in
wet season (-9 count/100ml, see Table 5.16) in WSR S1, and a minor decrease in both WSR
S2 and S3 in
wet season (-1 count/100ml, see Table 5.16). An improvement on
water quality and thus positive impacts to fisheries will be anticipated. And the maintenance of the facilities
would not have marine water quality impact as all components are
land-based. No operation phase
indirect impact under normal operation was identified.
Indirect Impact - Water Quality Changes (Emergency
Discharge from Cheung Chau STW)
9.6.8
In case of operational failure
of the Cheung Chau STW, raw sewage might bypass the wastewater treatment unit
and be directly discharged into the marine water. Water quality assessment
assesses the scenario of the STW emergency discharge in case of the STW
operational failure. The simulated
concentrations near the STW will increase sharply right after the emergency
discharge. Potential impact
of the Cheung Chau STW emergency discharge on water quality was predicted to
occur only to limited local areas close to the STW discharge outfall. The impact of the emergency discharge
will last for a short duration, decreases rapidly from its peak, impact returns
to the normal background level in less than 12 hours after the emergency
discharge is ceased. No adverse impact
is anticipated either to long term water quality conditions of the marine
receiving water. With regular maintenance and checking of plant equipment,
chances of occurrence of the incident will be very low. The potential impacts to fisheries
resources will be temporary in nature and is anticipated to be insignificant. As there will be no significant adverse
impact on the WSRs around Cheung Chau and in the vicinity, there will be no
significant adverse impacts on other fisheries resources farther away including
fishing grounds and important spawning grounds.
Indirect Impact - Water Quality Changes (Emergency
Discharge from Pak She SPS)
9.6.9
Sewage overflow may occur if
pumps fail or if there is an interruption to the electrical supply powering the
pumps. The overflow of raw sewage
from Pak She SPS will be diverted to the Cheung Chau STW for normal
treatment. The worst scenario of
STW failure has been assessed in Scenario 3. There will not be
significant adverse impact caused in Cheung Chau typhoon shelter. Similarly,
as there will be no significant adverse impact on the WSRs around Cheung Chau
and in the vicinity, there will be no significant adverse impacts on other
fisheries resources farther away including fishing grounds and important
spawning grounds.
9.7.1
The works involves land-based
construction works only, and water pollution control measures and good site
practices will be adopted to avoid impacts to nearby water bodies. In long term, there will be a positive effect
on the water quality after the upgrading works and hence improvement in the
marine habitat quality for fisheries resources. To this end, no unacceptable
impact on fishing resources is identified, and no mitigation measure and
monitoring programme would be required.
9.8.1
Evaluation of the fisheries
impacts is provided in Table
9.1. In
summary, no significant adverse fisheries impacts are anticipated. No residual impact is expected after
implementing standard site practices.
Table 9.1 : Evaluation of Fisheries Impact
|
Evaluation Criteria
|
Evaluation of Fisheries
Impact
|
|
Nature of impact
|
All works would be terrestrial
based and no works would be carried out in the marine environment. No direct impacts
have been identified during the construction phase. With implementation of the measures
outlined in ProPECC PN 1/94 Construction Site Drainage, indirect water
quality impact during construction phase is not anticipated. The habitat
quality for fisheries resources is expected to improve during the operation
phase of this Project.
|
|
Size of affected area
|
The affected area from the
indirect water quality impact is expected to be localised, small scale and in
the vicinity of the works area.
|
|
Loss of fisheries resources /
production
|
The waters surrounding Cheung Chau
are ranked as moderate importance in comparison to other areas in Hong Kong
in terms of fisheries production (including spawning and nursery ground) and
value. No direct loss of fishing resource / production is expected. Indirect
impact is expected to be insignificant with the implementation of
construction site water quality mitigation measures.
|
|
Destruction and disturbance of nursery and spawning grounds
|
The waters of Cheung Chau was previously identified in 1998 as
important fisheries spawning ground for high value commercial species. With
the implementation of site drainage measures, adverse water quality impact is
not expected. The potential indirect water quality impact on the spawning and
nursery grounds is anticipated to be negligible, their influence on fisheries
resources / production is therefore insignificant.
|
|
Impact on fishing activity
|
No
impact to the fishing activity is expected due to the absent of marine works
or disturbance of the seabed.
|
|
Impact on aquaculture activity
|
With the implementation of proper construction site drainage system to
contain and treat site runoff and wastewater prior to discharge, no adverse
water quality impact is expected to the Cheung Sha Wan FCZ which is located
over 2 km away from the Project Site.
|
9.9.1
The quality of effluent
discharge of the STW will be monitored by STW operators for compliances with
the proposed effluent discharge standards.
No specific fisheries EM&A programme would be required during the
construction phase of the Project.
9.10.1
A literature review has been
conducted to establish the fisheries baseline condition of the assessment area
and assessment of potential impacts conducted in accordance with the EIAO-TM
requirements. All works would be
land-based and no works would be carried out in the marine or intertidal
environment. With proper
implementation of water pollution control measures and good site practices, no
direct or indirect impacts have been identified during the construction
phase. Once upon completion of this
Project, the habitat quality for fisheries resources is expected to improve.
9.11
References
Ÿ
Agriculture Fisheries and Conservation
Department (AFCD) 2013a. Capture Fisheries. In:
http://www.afcd.gov.hk/english/fisheries/fish_cap/fish_cap.html (last revision 8 August
2013)
Ÿ
Agriculture Fisheries and Conservation
Department (AFCD) 2013b. 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 12 August 2013)
Ÿ
Black & Veatch Hong Kong Limited (B & V)
2009. Agreement No. CE 1/2008 (WS) Improvement of Fresh Water Supply to Cheung
Chau – Investigation. EIA Final Report 2831/B & V/015/ Issue 3
Ÿ
Environmental Protection Department (EPD) 2010.
Marine Water Quality in Hong Kong in 2010. The Government of the Hong Kong
Administrative Region, Hong Kong
Ÿ
ERM (1998). Fisheries Resources and Fishing
Operations in Hong Kong Waters. Final Report to AFCD
Ÿ
ERM (2006). Liquefied Natural Gas (LNG)
Receiving Terminal and Associated Facilities. EIA Report AEIAR – 106/2007