11.1.1
This Section summarises the
environmental outcomes associated with the construction and operation of the Improvement of Yuen Long
Town Nullah Town Centre Section.
11.2.1
Under this Project, the polluted DWF to the nullah will be intercepted
and treated in the YLEPP. Upon completion of the DWFI system under the Project,
the residents living along the Town Centre Section of YLTN will be immediately
benefited from the elimination of odour problem due to polluted DWF. In
addition, by intercepting the polluted DWF for proper treatment, the downstream
ecologically sensitive Shan Pui River and Inner Deep Bay will be benefited by
the improved water quality.
11.2.2
Further descriptions of the environmental outcomes of the Project are
presented in the following sections.
11.3.1
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.
11.3.2
Construction works of the Project will inevitably generate some fugitive
dust, especially during the excavation of the YLTN. With the sectioning construction approach,
the areas of excavation works should be limited in scale. Regular water spraying will also help to
control dust nuisance.
11.3.3
Through proper implementation of dust control measures required under
the Air Pollution Control (Construction Dust) Regulation, construction fugitive
dust should be controlled at source to satisfactory levels.
11.3.4
Maintenance works for the Project will be small-scale in nature. During the operation phase, the Project will
unlikely cause any unacceptable air quality impacts in terms of dust and odour. In addition, it is expected that odour
nuisance of the YLTN will be alleviated due to operation of the Project since
the polluted DWF originally discharged into the Project Site will be diverted
to the YLEPP. This is being considered
as a beneficial impact of the Project.
11.3.5
Cumulative air quality impacts associated with concurrent projects
within the Study Area have been considered, no unacceptable cumulative impacts
are anticipated with adoption of mitigation measures.
11.3.6
With the implementation of the recommended mitigation measures, it is
expected that the residual impacts from the construction and operation of the
Project will not exceed any relevant air quality criteria. As such no unacceptable residual air quality
impacts are envisaged from the construction and operation of the Project.
11.3.7
In order to ensure and demonstrate that mitigation measures are properly
implemented during the construction stage for reducing the air quality impacts
from the Project, weekly site inspections and audits as well as odour
monitoring will be conducted as part of the EM&A Programme of the Project.
11.4.1
A construction noise assessment has been undertaken to
predict the noise levels at the representative NSRs due to the construction of
the Project. Practicable mitigation
measures, including use of quiet construction plant, 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. Regular
noise monitoring at NSRs as part of the EM&A programme during the
construction stage is recommended.
11.4.2
Potential noise impact from the operation of the proposed DWF
pumping station has been assessed. The
predicted fixed plant noise levels at the representative NSRs due to the
operation of the proposed DWF pumping station and the cumulative noise levels
with the operation of the existing pumping stations 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.
11.5.1
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.
11.5.2
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 WSRs including the Deep Bay Wetland Conservation Area and Mai Po
Inner Deep Bay Ramsar Site.
11.5.3
During the operation phase, the interception of polluted DWF
by the Project is expected to lead to improvement of water quality within the
YLTN and at Shan Pui River and is thus considered to be beneficial. With regular maintenance works to remove
excessive sediments, it is anticipated that the Project will not lead to any
unacceptable water quality impacts by altering the sediment deposition and erosion
pattern of the Project Site and its downstream area. Unacceptable water quality impacts are also
not expected to occur at any identified WSRs including the Deep Bay Wetland
Conservation Area and Mai Po Inner Deep Bay Ramsar Site due to the small-scale
and infrequent maintenance works.
11.5.4
During emergency discharge of the collected DWF to the YLTN
(e.g. due to breakdown of the DWF pumping station), water quality of the nullah
is predicted to be similar to the existing condition
before operation of the Project. In
addition, given the low likelihood of the emergency discharge and proper
Emergency Response Plan will be in place and implemented, no unacceptable water
quality impact is expected to be associated with such discharge.
11.5.5
With proper implementation of the recommended mitigation
measures, it is expected that the residual impacts from the construction and
operation of the Project will not exceed any relevant water quality
criteria. As such, 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.
11.5.6
Cumulative water quality impacts associated with concurrent
projects within the Study Area have been considered with no unacceptable impact
anticipated.
11.6.1
Wastes generated by the construction activities are likely to
include C&D materials 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.
.
11.6.2
The recommended measures can be enforced by incorporating
them into the waste management requirements in the WMP as part of the EMP. Environmental site audit would be necessary
to ensure the implementation of proper waste management practices during
construction.
11.6.3
For the operation phase, only silt material and
debris are expected to be produced by maintenance works of the DWFI system. Such waste will be removed by manual means
and disposed of immediately after the clearance works. Small amount of screenings and chemical waste
will be generated during operation and routine maintenance of the DWF pumping
station. No unacceptable environmental impacts are anticipated with proper
waste management practices.
11.6.4
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.
11.7.1
A literature review and ecological field surveys have been
conducted. The ecological resources
recorded within the Study Area included ten habitats (agricultural land,
channelized watercourse, developed area, shrubland, mangrove, plantation, pond,
reedbed, semi-natural watercourse and tidal marsh) of which two occurred in the
Project Site (i.e. channelized watercourse and developed area). Total of 1 floral
species and 44 faunal species of conservation importance have been identified
within the 500m Study Area. Among them, four bird species were recorded within
the Project Area.
11.7.2
Given that construction works is
temporary in nature and of relatively small scale, and all the construction works will be confined within the channelized
watercourse and developed area with low ecological values, with the
implementation of the proposed avoidance/mitigation measures such as scheduling the construction of rising main within WBA outside
dry season, implementation of mitigation measures for water quality control as
detailed in Section 6.7 and good site practices, unacceptable adverse ecological impact is thus not
anticipated during construction.
11.7.3
Unacceptable ecological impacts are also not anticipated
during operation of the Project given the small-scale and temporary nature of
the maintenance works as well as the small percentage of reduction in
freshwater input to Shan Pui River due to the DWF interception. The ecological
sensitives areas and wildlife at downstream could be potentially benefited from
the improvement of water quality of Shan Pui River and Inner Deep Bay.
11.8.1
A Landscape Impact Assessment was undertaken for the
construction and operation of the proposed Project in Yuen Long Town
Centre. Landscape mitigation measures
were proposed as appropriate and residual landscape impacts have been identified. With proper implementation of mitigation
measures, all affected LRs and LCAs will have slight to insignificant
adverse landscape impacts during construction phase and insignificant or even no impact at both Day 1 and Year 10 the
operation.
11.8.2
A Visual Impact Assessment was also undertaken and VSRs were
identified and assessed based on their sensitivity and magnitude of
change. Visual mitigation measures were
proposed as appropriate and residual visual impacts identified. All VSRs will experience from moderate to insignificant visual impacts during construction phase after adoption
of mitigation measures. At Year 10 of operation, T2 and T3 will receive moderate visual impacts arising from
the proposed DWF pumping station while the remaining VSRs will receive nil or insignificant visual impacts.
11.8.3
Landscape and Visual Impacts are considered acceptable with
mitigation.
11.9.1 Monitoring of air quality (odour), noise and water quality has been recommended at designated sensitive receivers during the construction phase of the Project. Environmental site audit should be conducted weekly throughout the construction phase to ensure that the proposed mitigation measures are implemented.
11.10.1The environmental impact assessment has concluded that no unacceptable environmental impacts are envisaged as a result of the construction and operation of the Project, provided that the recommended mitigation measures are implemented. In addition, through interception of the polluted DWF for treatment at the YLEPP, it is expected that the odour nuisance at the Town Centre Section of YLTN will be alleviated with an overall improvement in water quality during operation of the Project.
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