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ATTACHMENT
1 |
Liquefied
Natural Gas (LNG) Receiving Terminal and Associated Facilities
- Further
Information Requested by EPD -
(i)
Clarification of the Environmental Impact
of Alternative marine transit
route
In the EIA report the transit of the LNG
Carrier via the west of Lantau was not considered as a viable alternative due
to water depth constraints. The
following text appears in Part 3, Section
13, Sub-section 3 Page 6.
“An
alternative approach to Black Point via the western side of
CAPCO understand that the Tonggu Channel
Project was proposed 14 May 2003 ([1]) and an EIA for the section of the route
in
Figure 1 – Previous Alignment of Tonggu
Channel passing through HKSAR Waters
The details of the project as it stood in
the Project Profile for the EIA were as shown in Table 1 below.
Table 1 Characteristics of the Tonggu Channel
Development
Roughly 20% of the dredging was proposed
for
“…the
Project will likely affect substantially the marine environment including the Chinese
White Dolphin and other marine life, thus putting them under high ecological
risk when the project is being constructed and in operation.”
CAPCO understands that a new alignment has
been proposed by the Tonggu Channel Project Proponent which is now entirely in
Mainland waters, as shown on Figure 2
below ([3]) .
Figure 2 – Present Alignment of Tonggu
Channel (hatched area is the
CAPCO
understands that this new alignment is a unidirectional channel with a width of
210m and a depth of -15.8m PD. The
majority of the 20 km route falls within the core area of the Pearl River
Estuary Chinese White Dolphin Nature Reserve. Under the regulations for this Nature
Reserve any “destructive activities” are prohibited in this area’. The Reserve is governed by a Protected
Area Management Board. The initial
dredging volume is around 50 Mm3 with a recurrent annual maintenance
dredging volume of 2.6 Mm3 per year.
As stated above the channel is at present
unidirectional with a width of 210m.
Although the depth of the channel is sufficient, additional dredging
would be required to increase the width of the channel so that it meets with
the PIANC[4] guideline of a minimum width of
250m. Also the PIANC guidelines indicate
that for safety reasons a 400m bidirectional channel is preferred.
The additional dredging associated with
widening the channel to 250m would be approximately 10 Mm3. There would also be the need to conduct
incremental annual maintenance dredging of 0.5 Mm3 per year for the
lifetime of the LNG terminal. Given
the presence of the Pearl River Estuary Chinese White Dolphin Nature Reserve,
CAPCO would have concerns regarding the incremental impacts that this dredging
work would pose.
If the Black Point option incorporated the
Tonggu Waterway then the total initial dredging volume of this option would
increase to 13.15 Mm3 which is extremely high when compared to the
In conclusion, while a carefully managed
and short term marine construction program can be compatible within a potential
marine reservation area, such as the waters of Southwestern Lantau, the
incremental dredging associated with incorporating the Tonggu Waterway into the
Black Point option makes it less favourable for environmental reasons when
compared to the South Soko option due to the environmental impacts associated
with significantly greater and more frequent dredging requirements.
(ii)
Clarification of the Landscape Visual
Impacts Arising from the Proposed LNG Terminal at Soko Island
The Landscape Impacts on
Part
2, Section 11.10 (page 28)
summarises the un-mitigated landscape impacts that the LNG Terminal would have
on the Landscape Resources (LRs) of
Mitigation measures are proposed in Section
11.11 (pages 29-31) and are illustrated in Figure 11.20. The resulting residual impacts on
the 12 Landscape Resources after year 10 of mitigation measures are not
expected to result in any Significant or Moderate/Significant
impacts on any of the LRs. There
will be moderate impacts on the
The
un-mitigated impacts on the Landscape Character Areas (LCAs) are analysed in Section
11.18, (pages 91-92). There
will be a Significant impact on the Islands Landscape, Moderate/Significant
impacts on the Inshore Waters landscape, a Moderate impact on the
Offshore Waters Landscape, and a Slight/Moderate impact on the Abandoned
Institutional Landscape.
Mitigation measures are proposed in Section 11.19 (pages 93-94) and are
illustrated in Figure 11.20. In addition to these mitigation measures,
Section 11.19.1 details avoidance
measures that also reduce the impact on the LCAs including the reduction of the
extent of the reclamation, the clustering of the tanks closer together, the
positioning of the tanks behind the hill at the northern end of South Soko and
an overall reduction in the total area of the terminal.
As a result of these mitigations measures,
all of the impacts on the LCAs will reduce in one order of significance
threshold. There will therefore be
a Moderate/Significant impact
on the Islands Landscape, a Moderate impact on the Inshore Waters
landscape, a Slight/Moderate impact on the Offshore Waters Landscape,
and a Slight impact on the Abandoned Institutional Landscape.
The visual impacts arising from the
development are described in Section
11.13.11 (Pages 48-78). Visual
Mitigation Measures are proposed in Section
11.14 (page 79). The LNG
Terminal has been carefully designed to minimize its potential visual
impacts. In particular the LNG
tanks which are the largest and most visible element, have been located at the
base of the hill at the northern end of the island to minimize their
visibility.
Of the 15 Visually Sensitive Receivers
(VSRs) analysed in the study, only marine visitors off South Soko Island will
experience a Significant impact with visitors to North Soko Island
experiencing a Moderate/Significant impact. Both of these VSRs are
located in close proximity to the LNG Terminal and experience low visitor numbers.
Due to the large distance between the LNG
Terminal and
According to the Technical Memorandum on the Environmental Impact Assessment Process
(EIAO-TM) the Landscape and Visual
Impacts are considered acceptable with mitigation.
Attached
to this document are Figures demonstrating the above points in further
clarity. These figures are:
•
Figure 1 – Further information on
Landscape Resource Mitigation
•
Figure 2 – Further information on
Landscape Character Mitigation
•
Figure 3 - Further information on
Landscape Character Mitigation
•
Figure 4 – Photomontage from
•
Figure 5 – Photomontage from Big Buddha
•
Figure 6 - Photomontage from
•
Figure 7 - Photomontage from
•
Figure 8 - Photomontage from
(iii)
Elaboration of the Commitment, Design,
Management, and Programme of the Proposed Enhancement Plan
Please See Attachment 2.
(iv)
Clarification of Underwater Noise Impacts on
Chinese White Dolphin and Finless Porpoises
Underwater Noise
The impacts of underwater noise on marine mammals have
been discussed at length in the EIA report. Sections of relevance are 9.7.1 page 43 and pages 47-50. The conclusion was that with specific
mitigation measures (Section 9.9.2)
and additional (precautionary) measures in place (Section 9.10) adverse residual impacts from underwater sound
generation are not expected to occur.
Cooling Water System
Underwater sound at the intake head will be minimal as
water will flow through the intake by means of gravity. The only sound generated through
extraction of seawater will be from the pumphouse, which will be located on
existing land within the LNG terminal footprint. On this basis, disturbance to marine
ecology, such as cetaceans, through underwater sound generated by the seawater
intake and outfall system is not expected to occur. It is is also considered important to note that the
findings of a two year marine mammal survey, the results of which are presented
in the Annexes to Section 9, indicate that very few sightings of marine mammals have
been made in the direct vicinity of either the intake or outfall systems.
(v)
Clarification of Impacts on Fish Fry and
Eggs Arising from the Operation of the LNG Terminal, Including the Seawater
Intake and Outfall System
Intake
Regarding the potential impacts to fish
eggs and juvenile fish as a result of seawater extraction for the operation of
the LNG terminal at
In addition, the maximum volume of water
proposed to be extracted for the operation of the seawater intake is
approximately 18,000m3 hr-1, which is similar in scale to
the volume extracted by other cooling water intakes in
The LNG terminal
volume of extracted water is relatively low when compared to the average hourly
volume of 323,280 m3 hr-1 (wet season) currently
extracted as part of the operation of the existing Hong Kong Electric Power
Station on
Total Residual Chlorine and Temperature
The cooling water system has been
described in the EIA and consists of an intake supply which will draw seawater
into the Open Rack Vaporiser system (ORV).
Within the ORV the seawater will warm up the LNG and in so doing become
cooled. When the seawater is
discharged from the ORVs it then gravity flows through an open culvert to the
discharge point underneath the LNG jetty.
As seawater flows through the culvert its temperature can be expected to
increase, although no account for this has been taken in the assessment.
Chlorine is added to the water as it
enters the seawater intake system in order to keep the ORV free of biofouling
organisms. Once added to the
seawater system, chlorine is diluted and a residual concentration of chlorine
remains within the discharged water.
This is termed Total Residual Chlorine, or TRC. In countries such as
For the LNG terminal, CAPCO has agreed to
discharge a maximum TRC concentration of 0.3ppm. Although a conservative approach has
been adopted (i.e. a continuous discharge at the maximum concentration),
potential impacts to marine life through such a discharge have been modelled to
assess environmental acceptability.
The results of this modelling and the
impact assessment of effluent containing TRC and reduced temperature have been
addressed in both the Marine Ecology (Section
9) and Fisheries (Section 10)
Impact Assessments in Part 2 of the EIA Report. The Water Quality Impact Assessment, in
which the results of the modelling
used to predict the pattern of dilution and dispersion of temperature and TRC
in marine waters at South Soko is discussed in Part 2 Section 6 of the EIA
Report.
The results of the modelling exercise were
compared and evaluated against applicable standards (i.e. the Water Quality
Objectives (WQOs) as well as relevant internationally applicable criterion for
marine ecological and fisheries assessments). The criteria adopted have been taken
from Environmental Impact Assessments (EIA) previously approved under the Environmental Impact Assessment Ordinance
(EIAO) in the Hong Kong SAR and international guidelines.
No exceedance of any of these criteria
have been predicted to occur at identified sensitive receivers as a result of
either the construction or operation of the LNG terminal and associated
facilities at either the South Soko or Black Point sites.
In terms of the potential impacts through
discharge of cooled water, it is also considered important to note that the
ambient temperature of the waters surrounding
Furthermore, the maximum temperature
difference at the closest sensitive receiver (False Pillow Coral on
The relevant sections of the EIA that
explain the impact to fish eggs and juvenile fish as a result of the intake and outfall system have been
extracted and are presented in Attachments
1A & 1B.
(vi)
Clarification of Ecological Impacts on the
Marine Mammals Arising from the Chlorinated Cooled Water Discharges
Issues concerning impacts from underwater
sound are presented above in Item (iv). Given that unacceptable impacts to marine
ecological and fisheries resources (ie the prey items of marine mammals) are
not predicted to occur (as discussed above in Item (v), unacceptable impacts to
marine mammals from the cooling water discharge are not predicted.
sUPPLEMENTARY iNFORMATION ON cOOLING wATER sYSTEM AND
iMPACTS ON mARINE lIFE
(i)
Cooling Water System and Impacts on Marine
Life
Cooling Water System Design
Extracted from Part 2 -
"In order to provide water
for regasification of LNG, seawater will be extracted from Tung Wan via
submarine intake. The intake will
extend approximately 300 m from the pumphouse to the offshore intake heads (Figures 3.9 and 3.10). It is proposed that a typical box
culvert design be employed and the intake structure comprises of a precast
concrete tower ballasted with mass concrete. The tower would be connected to the
seawater pumphouse by submarine pipelines.
The foundation will likely comprise a rockfill base placed directly over
the rockhead level following dredging by grab dredgers to remove a thin layer
of marine deposits beneath. The
intake from the tower would be placed at an approximate depth of approximately
–3 mPD. A cross-sectional drawing
of the conceptual intake is presented in Figure
3.10."
Cooled Water Impacts - Temperature
Impacts to Water Quality
(Part 2 –
Cooled Water Discharge
Cooled water with a temperature of
approximately 12.5°C
below ambient will be discharged at the seawater outfall, which is located
close to the seabed in the vicinity of the LNG carrier jetty. There are no water quality sensitive
receivers in the immediate vicinity of the proposed discharge point.
The maximum flow rate of the
discharge is expected to be equivalent to 18,000 m3 hr-1. Compliance with the WQO (D
±
2 °C
from ambient) must be achieved at sensitive receivers. The discharge of cooled water has been
simulated using computational modelling.
The results from the cooled water
discharge modelling are included in Annex
6G and have been presented as contour plots showing impacts of cooled water
discharges in the vicinity of the outfall.
Figures SK_G01-G02 show the
differences of the maximum temperature reduction between the maximum
operational discharges and the baseline, representing the most conservative
case.
It can be seen from the contour
plots that the extent of temperature change from ambient for both the wet and
dry seasons is predicted to be confined to the bottom layer, with no impact to
the surface layer of the water column and no impact at sensitive
receivers. This may be expected as
the discharge of cooled water is close to the bottom and the relatively higher
density of the cooled water results in weak vertical mixing.
Due
to the distance to sensitive receivers, no non-compliance with the WQO has been
predicted in either the dry or wet seasons. For the most conservative case (maximum
operational discharge, see Figures SK_G01
and SK_G02), the temperature change is predicted to be less than 2 °C
in both the dry and wet seasons.
The temperature change of 2 °C will be confined to < 200 m from the
outfall in the dry season and the wet season. The model results indicate that the
dispersion of cooled water is rapid and not expected to cause an unacceptable
impact.
Impacts to Marine Ecology
(Part 2 –
Cooled Water -
Temperature
Cooled water with a decreased temperature
of approximately -12.5°C from ambient will be discharged at the
seawater outfall, which is located at the sea bed on the south coast of South
Soko Island. The flow rate of the
discharge is equivalent to 18,000 m3 hr-1 (peak
flow). The discharge will be
compliant with the WQO (Part 2 Section 6). The potential impacts of this discharge
are principally related to the ecological effects in a zone of reduced
temperature near the point of discharge.
Impacts will be limited to a relatively small area in the bottom layer
of the water column (Part 2 Section 6). The results from the cooled water
discharge modelling obtained for both the wet and dry seasons have shown that
the temperature change is predicted to be confined to the bottom layer with
little or no impact to the surface layer.
As such impacts within the intertidal zone
will not be expected as there is little or no impact to the surface layer of
the water column (intertidal zone).
In deeper water or the subtidal zone, impacts to the benthos are
expected to be minor as the extent of the affected area is small.
Impacts to Fisheries Resources
(Part 2 –
Discharge
of Cooled Water
Induced temperature changes to natural
aquatic habitats have been proven to have detrimental effects on the physiology
of fishes. The decline in
temperature has the potential to alter the rate of development of fish embryos,
larvae and gonad maturation. A
slower growth rate means that fish larvae remain longer in the delicate early
development stages, potentially increasing mortality ([6])
. The altered development of gonad
maturation could ultimately reduce the spawning success of fish species and the
altered mechanism of muscle development ([7]) could potentially reduce the chance of
survival of juvenile fish.
Cooled water with a temperature of
approximately 12.5°C below ambient will be discharged from the LNG
terminal’s seawater outfall located near the bed layer of the water
column. The results of the water
quality modelling in Part 2 Section 6
have predicted that a temperature change exceeding the WQO of +/-2°C will remain in the bed layer within
approximately 200m of the outfall in the dry season and approximately 70m in
the wet season.
The results presented in Part 2 Section 6 indicate that the
impacts to seawater temperature caused by the open circuit process are
predicted to be localised.
Furthermore, from a review of the results of the Ichthyoplankton and Fish Post-Larvae Survey presented in Annex 10 it emerges that the sensitivity
of the fisheries resources in the proximity of the proposed LNG terminal is
medium-low due to the comparatively low density of fish larvae and post larvae
recorded, thus further reducing any potential adverse effects of the localised
temperature change.
It is therefore expected that the cooler
water discharge will not cause unacceptable impacts to the fisheries resources.
Cooled Water - Antifoulant
Impacts to Water Quality
(Part 2 –
Residual Chlorine Dispersion
Residual chlorine in the marine environment can be
harmful to marine organisms only if concentrations exceed tolerance
levels. It has been found that
harmful effects begin to occur at concentrations above 0.02 mg L-1 in
water ([8]). The discharge limit for residual
chlorine is 1.0 mg L-1 according to EPD’s Technical Memorandum for Effluents issued under Section 21 Water Pollution
Control Ordinance, Cap 358. There is no value specified in the WQOs
for the
The
water quality impacts due to chlorine discharges have been assessed using
computational modelling (see Water
Quality Method Statement in Annex 6A). The results from the chlorine
simulations are presented as contour plots of mean and depth averaged chlorine
concentrations for the spring and neap tidal periods in the wet and dry
seasons. The contour plots are
provided in Annex 6H. Figures
SK_H01-08 present the maximum operational discharges, while Figures SK-H09-16 show the fluctuating
operational discharges. Both
discharge rates appear to result in a similar pattern of residual chlorine
dispersion.
The
dispersion results obtained for both the wet and dry seasons have shown that the
majority of the residual chlorine is contained within the bottom layer, with
little or no chlorine in the middle and the surface layers. This indicates that the release of the
chlorine near to the seabed and the relatively higher density of the cooled
water, in which the chlorine is discharged, results in weak vertical mixing.
The
model used the assumption that the terminal would discharge total residual
chlorine at a maximum concentration of 0.3 mg L-1. This concentration is similar to that
for most power stations in
Based on the predictions, the maximum extent of the
> 0.01 mg L-1 contour is <300 m from the discharge point
during the dry season and <100 m during the wet season (Figure SK_H01 and Figure
SK_H05). These areas were
defined as the “mixing zones”.
Due
to the small extent of the plumes, and the fact that no sensitive receivers
would be affected, no unacceptable water quality impacts from residual chlorine
discharge are expected to occur.
The short duration peaks of residual chlorine discharge will also not
contribute to any unacceptable adverse impacts. The assessment confirms the
environmental suitability of the proposed discharge.
Impacts to Marine Ecology
(Part 2 –
Cooled Water -
Antifoulants
There are considerable operational and
ecological issues caused by organisms within, and passing through industrial
water systems and, these problems can be costly ([10]).
Mussels, oysters and other marine organisms growing within cooled water
circuits have resulted in losses in thermal efficiency and even total
shutdowns. To counteract settling
and actively growing fouling organisms, cooled water circuits are usually dosed
with antifoulants (typically chlorine in the form of sodium hypochlorite). The discharge of the resulting
(chlorinated) effluents may in turn have effects on the habitat beyond the
outfall.
The effluent from the cooled water system
will contain traces of antifoulant at a concentration of approximately 0.3 mg L-1,
which is below the EPD’s ([11]) statutory limit of 1.0 mg L-1.
Values for observed toxic effects of
chlorine are available from the literature and can be used for reference
purposes (Table 9.6). For the majority of organisms the toxicity
of residual free chlorine depends on the concentration and exposure time. Short exposure to high concentrations
often leads to lethal effects as do long term exposures to low concentrations ([12]).
Table 9.6 Toxic Responses
of Marine Organisms to Residual Free Chlorine in Discharges ([13])
|
Organism |
Toxic Responses |
Cl (mg L-1) |
|
Phytoplankton |
Photosynthesis
of marine phytoplankton depressed by 70-80% |
0.02-0.04 |
|
Zooplankton |
Short term exposure
has led to rapid but temporary responses demonstrated through depression in
metabolic rate and reproductive activity. |
0.01 |
|
Oyster
Larvae (Ostrea edulis) |
Tolerant of
short term exposure with no demonstrated toxic response. |
0.2-0.5 |
|
Barnacle
Larvae (Elminius modestus) |
Tolerant of
short term exposure with no demonstrated toxic response. |
0.2-0.5 |
|
Lobster
Larvae (Homarus americanus) |
Respiration
rate increased after 60 minute exposure to 0.1 mg L-1 and after 30
minute exposure to 0.1 mg L-1. |
0.01 0.1 |
Concentrations of residual chlorine
typically diminish rapidly with time and distance from the discharge
point ([14]).
The modelling exercises conducted for the water quality assessment
(reported in Part 2 Section 6)
indicate that residual chlorine concentrations exceeding 0.01 mg L-1
are only likely to occur within 300m of the outfall and are mainly confined to
the bed layer of the water column.
These predicted increases do not exceed tolerance thresholds established
in the literature (0.02 mg L-1) and are in accordance with those
levels recommended in previous studies in
Impact to Fisheries Resources
(Part 2 –
There are potential operational issues
caused by the growth or encrustation of marine organisms on the open loop
vaporization system (i.e., pipes, valves etc.). Operationally, the colonization of
marine organisms such as algae, bryozoans, molluscs and cirripedes within
cooled water circuits could result in losses in thermal efficiency and reduced
reliability of the system (including total shutdown). To counteract settling and growth of
marine organisms, cooled water circuits are typically dosed with chemicals
(usually sodium hypochlorite). Such
chemicals are known as antifoulants and they inhibit the growth of organisms
within the circuit by creating unsuitable living conditions. A secondary consequence of this form of
treatment is associated with the discharge of the treated seawater into the
marine environment.
Research has been conducted internationally
on the effects of chlorine discharges on marine ecological and fisheries
resources. The international review
provides data which can be used as a benchmark to evaluate potential impacts. Work on the toxic effects of chlorine on
fish eggs and larvae has indicated that abnormal development may occur at
concentrations of 0.31 to 0.38 mg L-1 ([15]).
However, behavioural studies have indicated that adult fish will avoid
areas where concentrations of free residual chlorine in the water exceed 0.035
mg L-1 ([16]).
The proposed LNG terminal is predicted to
discharge residual free chlorine at a concentration of < 0.30 mg L-1. This concentration is below EPD’s
discharge limit of 1.0 mg L-1 ([17]).
Concentrations of
residual chlorine have been shown to diminish rapidly with time and distance
from the discharge point ([18]).
A concentration of residual chlorine of 0.01 mg L-1 (daily
maximum) at the edge of the mixing zone is the criterion used in the Water Quality Assessment (Part 2 Section 6). The modelling exercise conducted in the
assessment indicates that maximum residual chlorine concentrations exceeding
0.01 mg L-1 are only likely to occur within 300 m of the outfall and
are mainly confined to lower layers of the water column. These predicted increases do not exceed
tolerance thresholds established in the literature (0.02 mg L-1) and
are consistent with levels recommended in previous studies in Hong Kong (0.01
mg L-1).
Consequentially, significant impacts to fisheries
resources as a result of the discharge of chlorinated water are not expected to
occur.
Impacts
to Fisheries Resources (cont’d)
(Part 2 –
Assessment
of Environmental Impacts
Nature
of Impact:
Discharge of cooled water is not predicted
to pose adverse impacts to fisheries resources and discharges of residual free
chlorine will be in compliance with the EPD’s allowable discharge limit.”
