14.1.1
This report presents the environmental assessment of the environmental
impacts relating to the proposed improvement to Tung Chung Road alignment
option. Full details of the
justification and background to the project are provided in Section 1. The preferred alignment has been selected
after a comprehensive option assessment process in which the environmental
implications of each alternative was a key consideration and the alignment
options selected deemed to be the most preferable on environmental grounds (see
Appendix B). The
avoidance and minimisation of environmental impacts as far as practicable has
been a major objective during the assessment and selection of the preferred
route and through the progressive design of the selected alignment. Thus, the proposed alignment represents the
optimum route after balancing all relevant factors, within the engineering and
topographical constraints.
14.1.2
The main characteristics of the alignment which have been designed to
minimise the environmental effects of
the road are as follows:
¨ alignment widened on-line as far as possible to minimise habitat loss;
¨ haul road specified along the same alignment as the main route as far as practicable to reduce the extent of temporary habitat loss;
¨ alignment designed on viaduct where appropriate and with the use of retaining walls in order to significantly reduce the extent of cut slopes required, having ecological benefits;
¨ alignment designed to cross all key ecologically sensitive streams on structure during both the construction and operational stages to avoid direct impacts on the aquatic environment;
¨ construction runoff in the northern section to be collected into a special pipeline and transported to the nullah in Tung Chung and treated via sedimentation tanks prior to discharge. This will avoid discharge into the northern streams which are tributaries of the highly sensitive Tung Chung stream. In the south, all run-off collected and treated using sedimentation tanks and oil interceptors prior to discharge to protect the streams and the water gathering grounds. Discharge into Cheung Sha Stream avoided;
¨ special pipe also designed to carry road runoff to either end of the alignment to avoid discharge into any stream course during the operational phase;
¨ permanent drainage system designed to avoid direct impacts on Fong Yuen Marsh and the channelised section of Tung Chung stream which is proposed to be upgraded; and
¨ layout and size of the bus bay facilities designed to minimise land take.
14.2.1
The assessment of construction related impacts have included: air
quality, noise, water quality, construction waste, ecology, landscape and
visual and hazard to life. The assessment of impacts during the operation of
the project have included: air quality, noise, water quality, ecology,
landscape and visual, hazard to life and heritage impacts.
14.2.2 The Remaining Development in Tung Chung and Tai Ho Comprehensive Feasibility Study has proposed sensitive development north of the Tung Chung Valley which could be affected by the operation of the improved Tung Chung Road. Thus, for the purposes of this report, the effects on this development together with the cumulative effects of the two projects have been assessed. In addition, the potential for operational air and noise impacts at proposed future sensitive receivers on the sale sites in Cheung Sha has also been assessed. The key findings of the EIA are given in Sections 14.3 and 14.4 below.
14.3 Summary of Key Findings and Recommendations
14.3.1.1
Potential dust nuisance will be the key concern from the
construction works. The major sources of dust on site have been assumed to be
from construction work, vehicular movement over unpaved haul roads and erosion
of exposed surfaces. Both 1-hour and 24-hour TSP concentrations at
representative ASRs along the route have been determined and based upon an unmitigated scenario it
is predicted that only some representative sensitive receivers would be subject
to dust impacts in excess of either the 1 hour or 24 hour standards. However, with the implementation of the dust
control measures, the impacts can be reduced to acceptable levels. Mitigation
measures recommended include:
¨ not burning debris or other materials on the works areas;
¨ watering all unpaved roads;
¨ watering exposed site areas;
¨ watering during rock breaking;
¨ minimising dropping heights for excavated materials;
¨ dampening and covering of materials during transportation;
¨ minimised areas of exposed soil and restored as soon as is practicable; and
¨ covering and watering all stockpiles.
14.3.1.2
In addition
to these measures, under the auspices of the Air Pollution Control
(Construction Dust) Regulation, the Contractor will be required to ensure that
dust control measures stipulated in the Regulation should be implemented to
control dust emissions.
14.3.1.3
Although
construction impacts are predicted to be reduced to acceptable levels through
the implementation of the recommended mitigation measures, construction phase
environmental monitoring and audit has been recommended to ensure that the
mitigation measures are effective.
Detailed specifications for the EM&A are provided in the EM&A
Manual.
14.3.1.4
Impacts on air quality
during the operation of the improved Tung Chung Road will be due to vehicular
emissions from traffic using the road.
Based morning peak hour traffic flows and vehicle mixes for the Year
2021, the worst case year for the operational air quality assessment 15 years
after the proposed opening of the road, and EURO 3 vehicular emission factors,
operational concentrations of nitrogen dioxide and respirable suspended particulates have been
predicted at all representative ASRs.
The results show that all parameters comply with the relevant AQOs. This conclusion also applies to the future
sensitive receivers in Cheung Sha.
Thus, no mitigation is required.
14.3.2.1
The
construction activities for the Project can be divided into five broad areas,
namely roadworks and bridgeworks for the main alignment and activities required
for the construction of noise barriers, stabilisation of unstable boulders and
slope remediation works. No blasting
works will be allowed along the road.
14.3.2.2
During slope
stabilisation works, the use of a helicopter for equipment drop off and pick up
will be required in certain areas. It
has been determined that due to the distance of the sensitive receivers from
the works areas, the noise levels is not expected to exceed the 75 dB(A)
standard or the 85 dB(A) maximum criteria.
The results of the construction works associated with the bridge works
and the slope stabilisation and remediation works showed that noise exceedances
were not predicted at the sensitive receivers.
14.3.2.3
However, the
results for the road and noise barrier construction indicate that, in certain
locations including Tung Chung Valley, maximum noise levels at some of the NSRs
will exceed the day time noise criteria of 75dB(A). Mitigation measures are, therefore, required to reduce the noise
levels to meet the standards. The
mitigation recommendations are as follows:
¨ silencers should be installed at the exhaust pipes for the engines of the bulldozers, lorries, concrete lorry mixers, chipper, poker, cranes, excavators and dump trucks;
¨ the poker should have an acoustic cover on the engine; and
¨
temporary noise barriers should be
used to screen construction activities at SRs 4, 13 and 15 during road
construction and SR 2 and 4 during permanent noise barrier construction.
14.3.2.4
In addition,
only one breaker should be used within 200m of SR4 in Tung Chung and SRs 13 and 15 in Cheung Sha and the operation time of the breaker, dump truck,
bulldozer and grader needs to be restricted by 50% at SR13 during excavation of
earth / rock and removal, forming of earthworks and retaining wall foundation
works. Use of the recommended
mitigation is sufficient to reduce noise levels to within acceptable limits for
all sensitive receivers, with in the region of 44 dwellings being protected by
these measures.
14.3.2.5
Operational
noise predictions have been carried out based upon peak hour traffic flows and
vehicle mixes for the worst case year of 2021.
The noise modelling has concluded that the majority of sensitive
receivers would not be subject to operational noise levels in excess of the 70
dB(A) limit as a result of their distance from the alignment. However, the village properties in Tung
Chung Valley are adjacent to the road and will be subject to elevated levels in
excess of the standard. Thus, direct mitigation measures are required for the
NSRs affected by the project. A full
range of mitigation options have been considered for the protection of the NSRs
to ensure that the optimum scheme is recommended.
14.3.2.6
Reflective
barriers, ranging in heights from 1.5m to 4.5m and totalling over 127m in Tung
Chung Valley have been proposed to protect the sensitive receivers from
operational noise impacts resulting from the project. Approximately 10
dwellings will be protected by these barriers in the Tung Chung area. Many of the properties in Ha Ling Pei and
Wong Ka Wai are subject to elevated noise levels from the existing Tung Chung
Road which is outside this project limit. The practicality of retrofitting of
barriers was investigated but due to constraints associated with the need to
maintain access points to the villages, only one section of 70m of barrier was
identified as being practical for future consideration. These properties are also not eligible for
indirect technical remedies.
14.3.2.7
Impacts at
some of the closer proposed future sensitive receivers at the sale sites are
also predicted and it is recommended that mitigation measures be provided to
protect the future receivers. The EIA
has shown that the inclusion of a 2m landscaped earth bund, together with a 4m
non building area, would be sufficient to protect the properties.
14.3.2.8
In order to
ensure the recommended mitigation measures are effective, noise monitoring
during both the construction and operational phases has been recommended. Detailed specifications for the EM&A are
provided in the EM&A Manual.
14.3.3.1
Potential
impacts during the construction phase will be relevant primarily to the inland
water courses, although downstream impacts in the marine waters at either end
of the alignment are possible.
14.3.3.2
The northern
section of the new road runs up along the east side of Tung Chung Valley above
Tung Chung Stream. The distance between the road and the stream varies along
the route. At Lung Tseng Tau, the stream is about 210 m away from the road.
However, as the road climbs the valley towards the crest at Pak Kung Au, the
road passes as close as about 30 m to the stream in several locations, whilst
crossing over a number of tributaries to the stream. In the southern section of the road, the alignment also passes
over two tributaries of the Cheung Sha Stream.
14.3.3.3
Thus, site
runoff has the biggest potential to cause impacts to inland waters during the
construction stage and careful design of a runoff catchment and treatment
system will be required. Pollution of
the sensitive streams in the study area represented one of the key environmental
problems to be addressed in the EIA.
The implementation of good construction site practices such as
restricting stock piling in areas near watercourses, covering stock piled
materials and minimisation of exposed areas to rain by carrying out reinstatement
as soon as possible, will be required to reduce the suspended solid
concentrations. However, given the
importance of the streams in the study area and the water gathering grounds, in
addition to the above, the widening of the road has been restricted to the east
side of the existing road as far as possible, such that during construction,
the existing road can be used as a buffer zone to help prevent any pollutants
from running into Tung Chung Stream. The only locations where roadworks will be
required on the west side of the existing road are in the vicinity of Burial
Ground No. 18L and Tai Tung Shan Service Reservoir. Also the selected alignment is the furthest from the Cheung Sha
stream.
14.3.3.4
In addition,
a drainage system has been devised to avoid / minimise water quality impacts as
far as possible. For the northern section of the new road, it is proposed that
the operational drainage system be constructed ahead of the main roadworks such
that it may be used to discharge the construction site runoff, thus avoid
discharging construction site runoff into the streams all together. The
discharge outfall for the northern section’s drainage system will be located in
the “Wong Lung Hang Channel” nullah near Ha Ling Pei and all discharge will be
treated via a sedimentation tank in order to minimise impact on Tung Chung Bay
and the San Tau SSSI. seagrasses. South
of the crest, it is proposed to use a series of peripheral surface channels to
encase sections of the works site to intercept and divert the surface runoff
from the hinterland and the construction site.
All run-off will be treated by a series of sedimentation tanks prior to
discharge into adjacent streams. Oil interceptors will also be used above the
catchwater to further protect the water gathering grounds.
14.3.3.5
The key
aspects of the proposed temporary drainage system which will be adopted to
ensure the protection of the water quality in the inland streams and Tung Chung
Bay during construction are as follows:
¨ system designed to have no discharge of site run-off into Tung Chung Stream;
¨ northern temporary drainage system will avoid discharge into any steams;
¨ system in the southern area divided into small sub-catchments to enhance control and minimise impacts;
¨ all run-off treated via a sedimentation tank prior to discharge either into streams in southern area or marine environment;
¨ oil interceptors used above catchwater to protect water gathering grounds;
¨ all parts of system will be regularly cleaned and maintained;
¨ hinterland runoff separated to protect from contamination; and
¨ system must be operational before the commencement of the permanent works.
14.3.3.6
Thus, based
upon the inclusion of these measures, the risk of adverse impacts to water
quality during the construction phase has been reduced to a negligible
level.
14.3.3.7
Impacts may
also result from the discharge of wastewater from temporary site storage areas
and maintenance and refuelling of plant and mitigation measures are
recommended. The effects of litter and
waste construction material can be limited by the use of good site management
practices and in respect of lavatory facilities for the workforce, chemical
toilets or on-site chemical treatment facilities would be required where
connection to a sewer is not practicable.
14.3.3.8
Stream
diversions, culverting, widening or bank strengthening works have been avoided
as far as possible on key ecological streams with the road passing over the
water courses on structure, with the exception of 4 streams. However, impacts on these 4 streams will be
very short term and not considered to be significant. The temporary haulage road has also been designed to pass over
the stream courses on bridges, thus, protecting against direct impacts to the
streams. Streams which do not support
any key ecological species and have low basal flow may be subject to new
culverts, widening of existing culverts and widening of existing bridge
structures. This will cause direct
impacts to the streams but in light of their low ecological importance and low
flow, impacts are not considered to be significant.
14.3.3.9
In addition,
to the drainage system described above, mitigation measures recommended to
reduce any impacts to acceptable levels include:
¨ minimising areas of exposed soil and undertake reinstatement within 3 weeks of areas being completed;
¨ covering of spoil heaps and avoid placement adjacent to any streams;
¨ no major stockpiles in the Country Park;
¨ no storage of fuel or oil in the country Park or water gathering grounds;
¨ no chemical wastes shall be stored in the water gathering grounds;
¨ no canteen facilities shall be located within the water gathering grounds;
¨ the Contractor shall comply with WSD’s General Conditions for Working within Water Gathering Grounds;
¨ the Contractor will be required to prepare a response plan to define procedures for the control, containment and clean-up of any spillage that could occur on the construction site;
¨ no maintenance activities which may generate chemical wastes shall be undertaken in the water gathering grounds;
¨ collecting run off from the roofs of site buildings and conveying to closed drains;
¨ using on-site chemical treatment and storage facilities for wastewater from the site offices and toilet facilities; and
¨ washing vehicle wheels prior to entering and leaving the construction site.
14.3.3.10
EM&A in
the form of water quality monitoring of all affected stream courses, together
with site inspections has been recommended during the construction period to
ensure the effectiveness of the mitigation measures. Detailed specifications for the EM&A are provided in the EM&A
Manual.
14.3.3.11
In respect
of operational water quality impacts, contaminants in the road surface runoff
are expected to be limited and, thus, impacts on the water quality of the
streams are expected to be negligible.
Notwithstanding, a specially designed carrier pipe along the length of
the road will collect and transport all road drainage to either end of the
alignment prior to discharge into the nullah at Tung Chung and Pui O Wan. Thus, operational discharge into all streams
along the route, and thus the water gathering grounds, has been avoided.
14.3.3.12
Once
discharged though the outfall, a dilution factor of at least 10 would be
expected relatively quickly and within a few tens of metres from the discharge
point. Thus, increases in
concentrations of water quality parameters in the receiving waters would be
centred within a short distance of the discharge points, much as is the case
for the natural streams at present.
14.3.3.13
In Tung
Chung, the peak road runoff only amounts to about 1% of the total peak natural
runoff. This value is further reduced
when the dilution in the marine environment is taken into account, with the
runoff from the road being equivalent to about 1% to 2.5% of the tidal volume
depending upon the particular tide, based upon a 1:50 year storm. Similar,
levels of contribution and dilution would be expected for the southern section
of the road and the discharge into Pui O Wan. Thus, any road runoff into the
bays at either end of the alignment would not be expected to result in a
significant increase in the concentration of the water quality parameters of
interest and will not result in a significant increase in the existing
pollutant load to Tung Chung Bay or Pui O Wan.
14.3.3.14
In the event
of an accident with a tanker, there is the possibility for the spillage of a
large volume of oil or chemicals. In this
case, the proposed road parapet over much of the roads length would prevent a
vehicle from leaving the road and the integrated permanent road drainage system
would help to protect the inland streams by collecting the spillage. Thus, in the event that a major spill occurs
on Tung Chung Road, a defined response plan has been recommended in order to,
not only be able to reopen the road as soon as possible to minimise distruption
to Lantau traffic, but also to minimise effects on the local ecological resources
and water gathering grounds. Should
some oil be discharged via the pipeline into the marine environment, the
receiving waters are large bodies of water which would facilitate rapid
dilution and dispersion. However, in
order to protect the Tung Chung Bay, an oil interceptor is proposed for the
discharge at the northern end of the alignment.
14.3.3.15
In view of
the predicted negligible effects of any runoff and the adopted drainage system
which avoids discharge into any streams or water bodies along the alignment,
impacts from road runoff are predicted to be negligible and no further
mitigation measures would be required.
14.3.4.1
The key
issue for waste management will be control of excavated materials. Waste quantities have been estimated from an
assessment of the cut and fill activities determined. It is predicted that there will be an overall surplus of
material, with approximately 118,520m3 required to be exported. Assuming an average truck capacity of 7.5m3,
approximately 15,800 vehicle trips would be required for the removal of the
material over the duration of the job, which would equate to around 4 trips per
hour. This is not predicted to yield
any significant environmental impacts, however, it is recommended that surplus
material generated in the northern section be removed via that end of the
alignment and the same for the south to reduce any disturbance to any one set
of sensitive receivers.
14.3.4.2
However,
waste management measures to control stockpiling, temporary storage and on-site
transportation requirements, which could lead to short-term dust and visual
impacts, particularly in Tung Chung and Cheung Sha where the majority of the
sensitive receivers are located will be required. Recommended mitigation measures
include:
¨ the Contractor shall identify a coordinator for the management of waste. The coordinator shall prepare and implement a Waste Management Plan which specifies procedures such as a ticketing system, to facilitate tracking of loads and to ensure that illegal disposal of wastes does not occur, and protocols for the maintenance of records of the quantities of wastes generated, recycled and disposed;
¨ training should be provided to workers about the concepts of site cleanliness and appropriate waste management procedure, including waste reduction, reuse and recycling;
¨ all material shall be reused on site as far as practicable, including formwork plywood, topsoil and excavated material;
¨ good site practice shall be implemented to avoid waste generation and promote waste minimisation;
¨ any surplus material generated shall be sorted on site into construction and demolition (C&D) waste and the public fill fraction. Suitable provisions shall be included in the construction contract to ensure that the Contractor sorts and recycles waste;
¨ trees and vegetation shall be stripped prior to site clearance, chopped and compacted;
¨ excavated material shall be reused as close to the point of excavation and as soon after excavation as possible and directly transferred to the area deposition;
¨ the surplus excavated material from the northern sections of the alignment shall be exported via the Tung Chung end of the works area and all other material will be exported from site to the stockpile in Mui Wo, subject to consultation with the Public Fill Committee prior to construction;
¨ stockpiled material shall avoid vegetated areas where possible and be covered with tarpaulins;
¨ major stockpiled areas shall be sited outside of the country parks area and away from stream courses;
¨ stockpiling shall be kept to a minimum;
¨ stock piled materials shall be contained in a designated area down gradient from any stream, as far as possible, or up gradient with a suitably constructed barrier to reduce loss of materials to the stream;
¨ no fuel/oil shall be stored within the Country Park or water gathering grounds;
¨ no chemical wastes shall be stored in the water gathering grounds;
¨ no canteen facilities shall be located within the water gathering grounds;
¨ the Contractor shall comply with WSD’s General Conditions for Working within Water Gathering Grounds;
¨ no maintenance activities which may generate chemical wastes shall be undertaken in the water gathering grounds and
¨ excavated material in trucks shall be covered by tarpaulins to reduce the potential for spillage.
14.3.4.3
Measures to
control general construction waste, chemical waste, general refuse and sewerage
will also be required. EM&A in the
form of the audit of the Contractor’s procedures, methods and waste management
controls are recommended during the construction phase. Detailed specifications for the EM&A are
provided in the EM&A Manual.
14.3.5.1
Key
ecological resources have been identified in the study area through literature
review and field surveys. These include
designated nature conservation areas, habitats and species which are protected,
rare, vulnerable to human disturbance or otherwise of conservation
interest. While the alignment has been
designed so far as practicable to minimise the impacts to these habitats and
species, some impacts will occur. Some
of the key habitats and species of concern which may be affected and for which
varying degrees of mitigation will be required include:
¨ secondary woodland along the alignment;
¨ streams along the route;
¨ shrub Pavetta hongkongensis, orchids Acampe rigida and Liparis viridiflora and tree Artocarpus hypargyreus; and
¨ habitats of amphibians and reptiles along the route including the Romer’s Tree Frog.
14.3.5.2
However, the
habitat loss has been minimised by restricting the footprint of the works and
widening the road on-line as far as possible.
In addition, impacts on key ecological streams have been avoided by the
road crossing over these on structure and the Fong Yuen marsh has also been
avoided by careful design of the permanent drainage system. Mitigation measures
are required however and a summary of the mitigation and enhancement measures
recommended to minimise predicted impacts are given below:
¨ control of site run-off to protect ecology of water courses, particularly important for the Tung Chung Stream and the Cheung Sha Stream;
¨ transplantation of the shrub Pavetta hongkongensis, orchids Acampe rigida and Liparis viridiflora and tree Artocarpus hypargyreus;
¨ special design of new culverts and culvert inlet and outlets for streams 19 and 21 (Figure 6.1) and culvert inlet and outlets for Stream 18;
¨
translocation of Hong Kong Newt, Lesser Spiny Frog and
Romer’s Tree Frog from streams 15, 18, 19 and 21;
¨
scheduling
of works in streams
15, 18, 19 and 21 to avoid the period April to June which is the key breeding
period for fish, amphibians and odonates;
¨
translocation
of Romer’s Tree Frog between Lung Tseng Tau and Shek Mun Kap;
¨
provision
of water filled pots as habitats for the Romer's Tree
Frog between Lung Tseng Tau and Shek Mun Kap;
¨
translocation
of isolated population of Beijiang Thick-lipped Barb in Stream 15 to tributary
of Tung Chung Stream;
¨
provision
of slope surfaces at step channels for aquatic fauna to move up and down stream
at the existing bridge at stream 15;
¨
provision of escape routes
from drainage channels for amphibians;
¨ provision of wildlife tunnels for faunal transfer;
¨ compensatory planting to mitigate for vegetation loss; and
¨ reinstatement of land temporarily required during construction within 3 weeks of the areas being completed.
14.3.5.3
The proposed
mitigation measures are considered adequate overall to fully mitigate all
identified impacts. However, minor
residual impacts on habitats are predicted based upon the fact that not all
woodland habitat loss can be mitigated in the short term. Also, some residual
impacts caused by the barrier effect of the road are expected but these will be
minor in light of the recommendation to construct wildlife tunnels at certain
locations along the road. All residual
impacts are considered to be acceptable within the benefits of the scheme.
14.3.5.4
Due to the
need to design translocation works in respect of the shrub Pavetta hongkongensis, orchids Acampe rigida and Liparis
viridiflora and tree Artocarpus hypargyreus, Hong Kong Newt, Lesser Spiny Frog, Romer’s Tree Frog and Beijiang
Thick-lipped Barb, EM&A in the form of a design specification audit has
been recommended during the design phase.
Design specification will also be required for the wildlife tunnels,
specialised culvert design and amphibian escape ramp. In addition, audit of the specialist works as well as the
implementation of the other mitigation measures during the construction phase
will be undertaken. Operational phase
EM&A during the first year of the operation of the project will also be
carried out to monitor the establishment and success of the transplantation
exercise. Detailed specifications for
the EM&A are provided in the EM&A Manual.
14.3.6.1
The land forms of Lantau contribute significantly to its
identity. Within the study area, lower
slopes are generally gentle and soil-covered.
These comprise loose material which is the result of landslides and ground slump. This is generally fairly unstable
material. Upper slopes are generally
steeper and more spectacular, comprising a topography of bare rock outcrop and
boulder strewn hillsides resulting in an often dramatic and rugged appearance.
In these upper valleys, the exposed location and the general instability
of the soils has inhibited the development of vegetation resulting in soils of
low fertility. Given their general
abundance their sensitivity to change is considered to be low. In the more sheltered, low-lying coastal
areas of Tung Chung Valley and in limited areas immediately above Cheung Sha
Beach deeper, more fertile soils can be found resulting from the presence of
dense woodland cover and formerly the long term farming of arable crops and
rice paddies. These areas are increasingly rare in Hong Kong and are considered
to be of medium sensitivity to change.
14.3.6.2
Large areas
of riparian, secondary woodland exist in the more sheltered valleys. These are a significant element in defining
the landscape character of Lantau Island.
Extensive areas of plantation woodland have also been established on various
hill slopes within the southern part of the study area as a result of
re-planting works following hill fires.
14.3.6.3
The
extensive use of retaining wall and use of structures along the alignment has
reduced the degree of slope works and in addition, the road will be widened
on-line as far as possible. Therefore,
the landscape and visual impacts of the road have been minimised through
careful design. Mitigation measures to minimise the extent of the remaining
impacts include:
¨ minimising working areas as far as possible;
¨ protection and retention of existing natural rocky outcrops, slope profiles, topography and ridgeline,
¨ protection and retention of existing stream courses;
¨ protection and retention of existing secondary woodland, plantation woodland and tall shrub vegetation where possible;
¨ transplanting of trees which are of high amenity value and stand a good chance of successful reestablishment;
¨ topsoil stripped and stored for re-use in the construction of the soft landscape works;
¨ grass hydroseeding of slopes and disturbed areas with 3 weeks of being completed;
¨ planting of native shrub species on newly formed and upgraded roadside slopes and areas disturbed by the works to compensate for shrub vegetation lost during construction;
¨ planting of native woodland species on newly formed and upgraded roadside slopes and areas disturbed by the works to compensate for woodland vegetation lost during construction;
¨ infill planting of native trees in areas of existing low shrub adjacent to the road, to enhance ecological diversity; and
¨ tree and shrub planting to screen the road, to provide visual interest and to provide shade and shelter.
14.3.6.4
It is
intended that the compensatory planting noted above will be able to recompense
for the woodland and shrubland lost and to help re-establish the landscape
pattern and reduce the visual impact of the road.
14.3.6.5
The
large-scale open nature of the landscape of the study corridor, make the
existing Tung Chung Road and the future improvement works to Tung Chung Road
highly visible.
Generally, the
landscape mitigation measures seek to minimise potential visual impact of
development, to screen sensitive views and to blend the new development into
the surrounding landscape. However, in
addition to those measures proposed to mitigate for landscape impacts, further
specific mitigation measures for visual impacts include:
¨ sensitively designed site hoarding, where applicable;
¨ sensitive architectural and chromatic treatment of new road structures, elevated bridge structures, abutments, retaining walls; and
¨ sensitive architectural and chromatic treatment of noise barriers.
14.3.6.6
The
alignment will be associated with negligible to moderate negative residual
impacts on landscape resources and character at the opening Year. Visual
impacts will tend to be less substantial and are likely to range from between
negligible to slight negative. These can be reduced to acceptable levels with
the implementation of the mitigation measures proposed, which should result
mostly negligible but with one or two slight or moderate residual landscape
impacts and very negligible to slight visual impacts by Year 10.
14.3.6.7
EM&A in
the form of audit of the detailed landscape specifications has been recommended
to be undertaken during the design phase to ensure that the recommendations of
the EIA have been fully incorporated.
In addition, audit of the landscaping works as well as the
implementation of the other mitigation measures during the construction phase
will be undertaken. Operational phase
EM&A during the first year of the operation of the project will also be
carried out to monitor the establishment and success of the compensatory
planting. Detailed specifications for
the EM&A are provided in the EM&A Manual.
14.3.7.1
While the
Cheung Sha Water Treatment works is not a designated PHI, the proposed road
falls within 500m of this facility. The
risk for the study area of the Cheung Sha WTW are calculated for both the
individual risk and societal risk in terms of PLL and FN curves, and the
results have been assessed for both the construction and operation phases (2006
and 2021). The individual risk levels for the route imposed by the Cheung Sha
WTW are below the HKRG limit of 10-5 per year, and are acceptable
and all the FN curves are acceptable and so no mitigation is expected to be
necessary for both the construction and operation phases.
14.3.7.2
The road link
contributes less than 5% of the total risk for the surrounding population and
thus, no significant increase in risk is observed resulting from the
development of the new Tung Chung Road.
Overall, the risk for the road is low and acceptable.
14.3.8.1
Impacts on
the potential archaeological features in the study area are associated solely
with the construction phase of the project, but the historical buildings may
also be affected by operation of the project.
The potential for impacts, and the lack of historical and archaeological
data from within the study area, dictated that site investigations be
implemented. The field assessment was
divided into archaeological site surveys and the assessment of historical buildings
and structures.
14.3.8.2
The
archaeological field evaluation, comprising walkover surveys, auger and test
pit excavation. The test pits in Cheung Sha revealed the presence of former
agricultural terraces and the three test pits conducted to the east of Tung
Chung Road all contained historical material from the Qing dynasty. Based upon
the distance from the alignment in Cheung Sha and the fact that the material
found in Tung Chung does not represent a significant archaeological deposit, no
mitigation measures are required.
14.3.8.3
The
historical buildings survey identified and recorded 23 structures in the study
area. It was determined that the
proposed alignment has been refined to ensure that it will not directly impact
on any historical building or structure.
However, the impacts to be assessed for the 23 recorded structures are
of a visual nature. The distance
from the development will provide a sufficient buffer zone during the
construction phase for these structures.
As the development consists of the improvement to an existing road,
there will be no new adverse visual impacts associated with the proposed
project during the operational phase. However, based on the findings of the HIA
the following mitigation measures are recommended:
¨ a shrine in Lung Tseng Tau lies approximately 10 metres from the alignment. The shrine should be left in situ. During the construction phase, if the shrine falls within the works area of the project a protective barrier such as a metal fence should be erected around it; and
¨ the Fong Yuen nunnery compound lies at a minimum distance of 50 metres from the road alignment and the following mitigation is recommended:
- the 50 metre wooded buffer zone between the road and the nunnery should be retained to maintain the existing screening of the compound from the road during the construction and operational phases of the project;
- planting of foliage along the cycle path in the vicinity of the monastery in order to maintain the existing environment; and
-
during construction of the cycle path,
the main building should be fenced off and kept separate from the works area.
14.3.8.4
In light of
the need for mitigation measures to protect the shrine in Lung Tseng Tau and
the Fong Yuen Nunnery, EM&A during the construction period is
recommended. This will ensure that the
mitigation measures and the surveys are implemented.
14.3.9 Environmental Monitoring and Audit
14.3.9.1
In
accordance with the EIA, EM&A procedures are required during the design,
construction and operational phases of the project implementation. The EM&A works during the design phase
shall comprise an iterative audit process of specific design elements. The specifications for certain ecological
and landscape mitigation measures recommended by the EIA will be required to be
designed during the detailed design phase of the project.
14.3.9.2
During the
construction and operational phases, the EM&A requirements are divided into
environmental monitoring and/or project auditing in the form of site inspection
and supervision. Environmental
monitoring and audit for dust, noise and water quality during the construction
phase is recommended in order to ensure all proposed mitigation measures are
implemented and effective. All three
of these parameters will also be subject to audit through site supervision.
14.3.9.3
Site
supervision and procedures audit will be required during the construction phase
to ensure the proper handling, storage, transportation and disposal of the
various waste arisings from the project.
Audit of the implementation of the design elements and mitigation measures
to avoid ecological, landscape and visual and heritage impacts have also been
recommended by the EIA, and thus, monitoring in the form of regular site
inspections shall also be required to ensure mitigation measures are being
implemented and are effective. EM&A
for both ecology and landscape and visual resources will extend through the
construction phase and into the operational phase to ensure landscape and
ecological planting/replanting has been effective.
14.3.9.4
Operational
noise monitoring shall be undertaken during the first year, in months 6 and 12,
of the operation of the project to assess the effectiveness of the direct noise
mitigation measures recommended by the EIA.
14.3.9.5
Full details
and specifications for the recommended EM&A works are provided in the
EM&A Manual.
14.3.10.1
There is
only one key interface with the proposed improved Tung Chung Road, situated at
the northern end of its alignment, namely the proposed development in Tung
Chung and Tai Ho. The development in Tung Chung is being assessed under the
Remaining Development in Tung Chung and Tai Ho Comprehensive Feasibility Study
(CFS) currently being conducted by the Territory Development Department. The development proposals of relevance to
this study involve the development of the Tung Chung Valley.
14.3.10.2
The
assessment of cumulative impacts includes air quality, noise, water quality,
waste, ecological factors and landscape and visual impacts during both the
construction and operational phases as appropriate.
14.3.10.3
The
assessment has concluded that few cumulative impacts will occur based upon the
implementation of the two projects.
Sufficient mitigation measures to reduce any impacts to within
acceptable levels have been recommended for both the CFS and the improved Tung
Chung Road and additional mitigation measures are not considered to be
required.
14.3.10.4
Cumulative
noise impacts are possible during permanent noise barrier construction in Tung
Chung for the Tung Chung Road and either road works or site development for the
Tung Chung Valley project. Cumulative
impacts can be avoided by the careful scheduling of the works which would
prevent noisy equipment working simultaneously.
14.3.10.5
Impacts at a
proposed primary school adjacent to the Tung Chung Road are predicted with the
main noise contribution being from the section of the improved Tung Chung Road
which will be improved by Territory Development Department. Notwithstanding, a 4m landscaped earth bund
between the road and the proposed school site has been proposed to protect the
school from road traffic noise. The
bund is sufficient to reduce noise levels to within the 65dB(A) limit for the
school.
14.3.11.1
The design
of the proposed road link has been optimised to minimise the extent and
magnitude of environmental impacts, particularly the loss of habitat by
minimising the footprint of the works as far as possible. Also, retaining walls
have been used extensively to minimise the extent of the cut slopes and bridges
have been used to traverse the key ecologically sensitive streams and key
habitats such as the Fong Yuen Marsh have been avoided.
14.3.11.2
Where, the
implementation of the new road will result in some impacts, a comprehensive
range of mitigation measures has been recommended to reduce these impacts to
acceptable levels. Apart from the
mitigation of direct impacts, it is worth noting that
some of these measures, will not only mitigate impacts, but will also enhance
the existing environmental conditions as follows:
¨ the incorporation of wildlife tunnels under the at-grade sections of road;
¨ sensitive design of culverts and culvert inlets and outlets to allow fish and other aquatic faunal access;
¨ provision of slope surfaces at step channels for aquatic fauna to move up and down stream at the existing bridge at stream 15;
¨ provision of escape ramps in drainage channels for amphibians;
¨ provision of water filled pots as habitats for the Romer's Tree Frog; and
¨ the relocation of key floral and faunal species.
14.3.11.3 In addition, the proposed
remedial works to the existing slopes using bio-engineering techniques (ie,
hydroseeding instead of spray applied concrete) will enhance the existing
slopes, resulting in areas of higher ecological value.
14.3.11.4 Furthermore, the proposed
special permanent drainage systems will avoid carriageway runoff from being
discharged into both the Tung Chung and Cheung Sha streams and also the water
gathering grounds. This is will be an improvement on the existing conditions,
whereby carriageway runoff is discharged directly into the small streams,
watercourses and hillsides directly below the existing road.
14.3.11.5
Overall, the
environmental impacts predicted for all environmental parameters can be reduced
to acceptable levels with the implementation of the recommended mitigation
measures. Low residual impacts on habitats are predicted based upon the fact
that not all habitat loss can be mitigated in the short term. Residual impacts caused by the barrier
effect of the road are expected but these will be minor in light of the
recommendation to construct wildlife tunnels at at-grade sections of the road.
14.3.11.6
Residual
landscape and visual residual impacts will occur but the landscaping proposals
will fully mitigate for the loss in the long term. All the residual impacts of
the project are considered acceptable within the overall scope and benefits of
the project.