13.5 Waste Management and Land
Contamination
13.9 Landscape and Visual Impact
13.10 Environmental Monitoring
and Audit (EM&A)
13.1.1
The YLBS is proposed to enhance the flood protection level of the
existing Yuen Long Nullah (YLN) and Kam Tin River (KTR) and minimise the
flooding risk in accordance with DSD¡¦s Stormwater Drainage Manual (SDM),
accounting for future development and climate change. The construction works
under YLBS is anticipated to commence in Q4 of 2022 for completion by Q3 of
2029.
13.1.2
The proposed revitalisation works under the Project would enhance the
social connectivity of YLN and its surroundings into an aesthetically-pleasing
environment. The aim is to promote water-friendliness, ecological enhancements,
biodiversity and beautification of YLN, taking into consideration of their
effects on hydraulic performance.
13.1.3
This Environmental Impact Assessment (EIA) Report has been prepared for
the proposed Yuen Long Barrage Scheme (the Project) in accordance with the
requirements set out in the EIA Study Brief (ESB-307/2018) and the Technical
Memorandum on EIA Process (EIAO-TM). Aspects that have been considered in this
EIA Report include:
¡P
Air Quality;
¡P
Noise;
¡P
Water Quality;
¡P
Waste Management and Land Contamination;
¡P
Ecology;
¡P
Fisheries;
¡P
Cultural Heritage; and
¡P
Landscape and Visual.
13.1.4
A summary of environmental impacts identified in this EIA is provided in
Appendix 13.1. The conclusion of the
technical chapters of this EIA is described in the following sections.
13.1.5
The key assessment assumptions, limitation of assessment methodologies
and related prior agreements with EPD / other authorities on assessment of
different environmental aspects are given in Appendix
13.2.
13.2.1
The potential sources of air quality impacts associated with
the construction and operation of the Project have been identified and the
potential impacts were evaluated.
13.2.2
Potential impacts of dust, gaseous and
odour emissions from construction activities have been considered. With implementation of standard
construction practices and mitigation measures, no unacceptable impact on air
sensitive receivers (ASR) is anticipated. Potential odour nuisance from screened
debris/materials will be removed on demand basis to maintain the function of
the pumping station as well as to preclude any potential odour impact during
operation. As
such no unacceptable residual air quality impacts are envisaged from the
construction and operation of the Project.
13.2.3
Cumulative air quality impacts associated with concurrent
projects within the Study Area have been considered, no unacceptable impacts
are anticipated.
13.3.1
A construction noise assessment has been undertaken to
predict the noise levels at the representative noise sensitive
receivers (NSRs)
due to the construction of the Project.
Practicable mitigation measures, including good construction site
practices, use of quiet construction plant, movable noise barriers, noise
insulation sheet and scheduling of construction activities, have been
recommended. With the
implementation of the recommended mitigation measures, the predicted
construction noise levels at all NSRs comply with the noise criteria during the
daytime period. Therefore, no
unacceptable noise impact is expected to arise from the construction
activities. Also, no unacceptable
cumulative impact or residual impact is anticipated.
13.3.2
Potential noise impact from the operation of the proposed
pumping stations has been assessed.
The predicted fixed plant noise levels at the representative NSRs due to
the operation of the proposed Barrage Scheme comply with the day-time and
night-time noise criteria. No
unacceptable residual impact is anticipated. Attenuation measures, if required, will
be provided to the fixed plant items for achieving the compliance of EIAO-TM
noise criteria during the detailed design stage.
13.4.1
The potential sources of water quality impacts associated
with the construction and operation of the Project have been identified and the
potential impacts were evaluated.
13.4.2
Potential impacts arising from the proposed construction
works are predicted to be largely confined to the specific works areas. With proper implementation of the
recommended mitigation measures, in particular the establishment of dry
condition for excavation works within the existing nullah and adoption of good
construction site practices as recommended in relevant regulatory guidelines,
unacceptable water quality impacts are not expected at the identified water
sensitive receivers (WSRs) including the Deep Bay Wetland Conservation Area and
Mai Po Inner Deep Bay Ramsar Site.
13.4.3
During the operation phase, the existing tidal condition will
be shifted downstream from the existing inflatable dam to the proposed barrage.
The water quality at the upstream of the barrage is expected to be
improved. Practicable designs
including energy dissipators or refinements of the orientations of the pump
outlets will be optimised in the detailed design stage to dissipate excess energy
of flowing water downstream such that the hydraulic performance of the
downstream will be as similar to the existing condition as possible. Therefore,
the potential sediment erosion impact or increases in suspended solids to
nearby waters, mangroves, ponds and ultimately Deep Bay, due to the operation
of the barrage are not anticipated. With regular maintenance works to remove
excessive sediments, it is anticipated that the Project will not lead to any
unacceptable water quality impacts. Unacceptable water quality impacts are also
not expected to occur at any identified WSRs due to the small-scale and
infrequent maintenance works.
13.4.4
With proper implementation of the recommended mitigation
measures, no unacceptable residual water quality impacts are envisaged from the
construction and operation of the Project. Nevertheless, a monitoring programme
is recommended during the construction phase to verify the predictions of the
EIA and ensure compliance with the assessment criteria.
13.4.5
Cumulative water quality impacts associated with concurrent
projects within the Study Area have been considered with no unacceptable impact
anticipated.
13.5.1
Wastes generated by the construction activities are likely to
include construction and demolition (C&D) materials,
excavated sediment and floating refuse from the construction works, general
refuse from the workforce and chemical waste from any maintenance of
construction plant and equipment.
Provided that these identified wastes arisen are handled, transported
and disposed of using approved methods and that the recommended good site
practices are strictly followed in terms of the avoidance-minimisation-reuse-recycling-disposal
hierarchy, unacceptable environmental impacts are not anticipated during
construction of the Project.
13.5.2
The recommended measures can be enforced by incorporating
them into the waste management requirements in the Waste Management Plan (WMP)
as part of the Environmental Management Plan (EMP). Environmental site audit would be
necessary to ensure the implementation of proper waste management practices
during construction.
13.5.3
For the operation phase, trash and sediment are expected to
be produced by maintenance works of the tidal barrier. Such waste will be
removed by manual means and disposed of to landfill immediately after the
clearance works. Small amount of
screenings and chemical waste will be generated and
collected during operation and routine maintenance of the pumping stations.
No unacceptable environmental impacts are anticipated with proper waste management
practices.
13.5.4
A review of past and present land uses of the project site
was conducted. Based on desk-top review and site walkover, the presence of
contaminated land is not expected.
13.6.1
A literature review and ecological
field surveys have been conducted. A total of 14 habitat types, including
channelised watercourse, semi-natural watercourse, pond, abandoned wet
agricultural land/freshwater marsh, tidal marsh, mangrove, reedbed, mitigation
wetland, shrubland, agricultural land, mixed woodland, plantation and wasteland
and developed area, were recorded within the 500m assessment area, with
channelised watercourse, plantation and developed area being the habitats
recorded within the Project Site. The ecological values of the wetland
associated habitats including channelised watercourse (only YLTN Section 4,
SPR, KTR), semi-natural watercourse, pond, abandoned wet agricultural
land/freshwater marsh, tidal marsh, mangrove, reedbed and mitigation wetland
are at least low to middle, middle or middle to high. The other habitats,
except shrubland, plantation in NSW, which are of low to middle ecological
value, are considered of low or very low ecological value. Species of
conservation importance recorded within the 500m assessment area included 2
flora, 3 mammals, 51 avifauna, 5 herpetofauna, 9 butterflies, 3 odonates, 1 aquatic fauna and the endemic Bent-winged
Firefly. Only 14 avifauna of very low abundance and 1 fish species of
conservation importance were recorded within the Project Site.
13.6.2
Potential
direct impacts on natural habitats and recognised sites of conservation
importance within the assessment area except Wetland Buffer Area (WBA) inside
Project Site have been avoided through confinement of construction works within
the proposed works area. Only 0.29 ha of plantation of low ecological value
will be lost permanently, while net wetland loss will not occur due to the
decommissioning of the existing inflatable dam to release some space and the deepening of the bed of the watercourse
together with the operation
of tidal barrier can allow waters from Deep Bay flush in 50m beyond the location of the existing inflatable dam to offset the wetland loss
(i.e. 0.26ha watercourse) due to the permanent structures at the channelised
watercourse.
13.6.3
Major indirect impacts due to construction noise disturbances
from demolition works using excavator mounted breakers and piling works on key
wetland habitats within the assessment area and in close proximity to the
Project Site as well as migratory/overwintering waterbirds have been avoided
through scheduling of such noisy construction works outside dry season (i.e.
November to March, which is the peak overwintering period of waterbirds).
13.6.4
As the YLN S4 will be enhanced ecologically, with the design
of the tidal barrier to allow brackish waters flushing in the YLN, no negative
ecological impacts due to habitat loss are predicted. On the other hand, the
flight-line of waterbirds to-and-fro the YLN S4 and SPR were limited, with the manoeuvrability of waterbirds and
the unlikely feeding and roosting grounds in the upstream of YLN, potential
impacts to flight-line of waterbirds due to the barrage is considered minor.
13.6.5
Hydrodynamics at the Old Kam Tin River as well as SPR will
not be changed significantly due to the large waterbody of Deep Bay. While the
scouring effects to the exposed mudflat during low tide can be minimised by good discharging design. As there will be no
strong artificial lighting, with the proposed mitigation
measure in place, potential impacts from light to nocturnal life including
Mai Po Bent-winged Firefly are considered minor.
13.6.6
Mitigation measures have been proposed during construction
stage. According to the ecological survey data from present study, Shan Pui
River recorded a relatively higher abundance of waterbirds in dry season. In
order to minimise the construction noise disturbance on the nearby wetland
habitats and the associated disturbance-sensitive overwintering/migratory
waterbirds, which are most abundant during the dry season months, the
comparatively disturbing construction works i.e. percussive piling works and
demolition using breakers mounted on excavators, would therefore be scheduled
outside the dry season (i.e. November to March, which is the peak overwintering
period of waterbirds). In addition, a pre-construction survey is recommended
for areas within 100m from the Project boundary to confirm the location and
status of the night roost. Ardeid night roost was recorded at a site along Kam
Tin River. No
construction works should be undertaken within 100m from any night roost
confirmed by the pre-construction survey after 17:00 from February to September
and 16:30 from October to January to avoid disturbance to ardeid night roost. Within
YLTN Section 4 of the Project Site, fish species of conservation importance
i.e. Gobiopterus macrolepis
was recorded. Direct impact to this species is likely in the works area of the
tidal barrier during construction phase, and translocation of this species is
recommended. Capture-and-translocation of this fish species will be implemented
in the works area of the tidal barrier and pumping station prior to
construction works to minimise the impacts on this species of conservation
importance.
13.6.7
With the implementation of the recommended mitigation
measures (e.g. avoidance of noisy construction works and use of alternative
quieter construction method during peak overwintering period within dry season;
provision of noise barriers around Project Sit, provision of movable noise
barrier/acoustic mat for piling plants and breaker; use of enclosure for
construction plant, use of QPME; restriction of construction hours of
construction activities within specified months,
etc.), no unacceptable adverse residual impacts would be expected during
construction and operational phases.
13.7.1
A study
based on existing information on pond culture fisheries resources and
activities within the assessment area has been undertaken, following the
criteria and guidelines for evaluating and assessing fisheries impact as stated
in Annexes 9 and 17 of the EIAO-TM.
13.7.2
The proposed construction works will
be conducted within the proposed project boundary. No loss of active or
inactive fishponds are anticipated within the assessment area. There would
be no loss of oyster culture area or fishing ground near Deep
Bay. With the implementation of mitigation measures recommended for
controlling water quality impact, the Project would not cause any unacceptable water
quality impact to adjacent fishponds or oyster culture area and fishing ground
near Deep Bay during construction and operational phases.
13.8.1
It is
recommended that the moderate archaeological potential of this area as
mentioned in Agreement No. CB20120293 Planning and Engineering Study for the
Public Housing Site and Yuen Long Industrial Estate Extension at Wang Chau
Final Technical Report No. 3G (TR-3G) Preferred Option and Technical Assessment
¡V Environmental Impact Assessment Report (Arup 2014) should be reviewed if this
area is affected by any proposed works under this Project in future.
13.8.2
The
desk-based review and Built Heritage Survey recorded five Graded historic
buildings, a Nil-Grade and thirty-two not-graded buildings, three villages with
Fung Shui Woodlands alongside five major festivals. The assessment concluded the Graded
Historic buildings will not be affected by the Project."
13.8.3
Assessment
also concluded four not-graded built heritage items may be affected during the
construction phase: HB-17 and
HB-18, village houses in Ma Tin Tsuen, and HB-30, a Village God Shrine and
HB-31, a Buddhist Stone Tablet.
Mitigation measures such as condition survey (prior to construction
phase) with vibration monitoring during construction is recommended for the
village houses (HB-17-18) and shrine (HB-30). In addition, buffer zones to
safeguard the physical safety of the heritage structures and measures to ensure
safe public access during construction phase is recommended for the four
heritage structures (HB-17, HB-18, HB-30 and HB-31).
Yuen Long Barrage Scheme
13.9.1
Temporary adverse visual impacts will be observed during the
construction phase, however beneficial landscape and visual impacts will be
observed during the operation phase due to the enhancement of the nullah
channel and the integration of the nullah barrage with the landscape.
13.9.2
In accordance with Annex 10 of the EIAO-TM, it is considered
that, with the landscape and visual enhancement brought by this project such as
revitalisation works proposed in this project and the
mitigation measures proposed,, the proposed development will result in overall
beneficial landscape and visual impacts as it will complement the landscapes
and visual character of its setting, follow the planning objectives and will
improve the overall landscape and visual quality.
Kam Tin River Parapet
Modification
13.9.3
In accordance with Annex 10 of the EIAO-TM, it is considered
that the parapet modification works will in overall terms be acceptable, that is
there will be no significant effects on the landscape and no significant visual
effects or interference with key views.
13.9.4
In
accordance with Annex 10 of the EIAO-TM, it is considered that the parapet
modification works will in overall terms be acceptable, that is there will be
no significant effects on the landscape and no significant visual effects or
interference with key views.
13.10.1
Monitoring of noise, water quality, ecology, cultural
heritage, and landscape and visual impact has been recommended during the
construction phase and where appropriate operational phase of the Project. Environmental site audit should be
conducted weekly throughout the construction phase to ensure that the proposed
mitigation measures are implemented.
13.10.2 The detailed EM&A
programme is presented in a standalone EM&A Manual.
13.11.2
The proposed revitalisation works under the Project would enhance the social
connectivity of YLN and its surroundings into an aesthetically-pleasing
environment. The aim is to promote water-friendliness, ecological enhancements,
biodiversity and beautification of YLN, taking into consideration of their
effects on hydraulic performance.
13.11.3 The EIA has identified and assessed the potential environmental impacts during the construction and operation of the Project in accordance with the requirements set out in the EIA Study Brief (ESB-307/2018) and EIAO-TM. The EIA has concluded that with the implementation of the recommended mitigation measures, no unacceptable environmental impacts are envisaged as a result of the construction and operation of the Project and the Project would be in compliance with the applicable environmental legislation and standards.
END OF TEXT