2.1.1
The works for this Project in
Cheung Chau mainly comprises the following items and as shown in Layout Plan of
Figure
2.1:
(a) Upgrading of the existing Cheung Chau STW;
(b) Upgrading of the existing Pak She SPS by increasing the pumping
capacity; and
(c) Sewers works in Cheung Chau including upgrading/rehabilitation of
the existing sewers at Cheung Chau and provision of new sewers to unsewered
areas/villages including Tai Kwai Wan San Tsuen, Pak She San Tsuen, Nam She
Tong, Fa Peng, Chi Ma Hang, Round Table Villages, Tai Shek Hau and Sin Yan
Tseng, Tai Tsoi Yuen Kui, Ko Shan Tsuen and Lung Tsai Tsuen.
Sewage Treatment Works
2.1.2
Existing Cheung Chau STW is
located at the western side of the Cheung Kwai Estate. It is currently a primary treatment works
with design capacity of 4,000 m3/d. Upon completion of the Project,
it will be increased to a capacity of 9,800 m3/d with secondary
treatment level. A Membrane-bioreactor
(MBR) type sewage treatment plant will be adopted.
2.1.3
Conventional secondary sewage
treatment generally involves the biological degradation of organic content in
the influent followed by secondary sedimentation to settle out the sludge from
the aqueous activated sludge solution.
Rather than employing sedimentation, an MBR system passes the aqueous
activated sludge solution through membrane filtration to separate water from
the sludge. The MBR systems can operate
at a considerably higher mixed liquor suspended solids concentration and
provide an effective and reliable barrier, therefore MBR system has smaller
footprint, superior effluent quality and less sludge production over the
conventional process. All the MBR
modules will be placed in MBR tanks, which are covered and installed indoor.
2.1.4
The STW upgrading works will
include construction of new treatment facilities and also effluent reuse
facilities to reuse portion of the treated effluent for non-potable uses within
STW. All the upgrading works will be
constructed within the existing site boundary of Cheung Chau STW. Proposed general layout of the Cheung Chau
STW and the Schematic Flow Diagram are shown in Figure 2.2 and Figure 2.4, respectively.
Sewage Pumping Station
2.1.5
Existing Pak She SPS was
commissioned in 1984 and is located at the junction of Pak She Praya Road and
Ping Chong Road, opposite to the Cheung Chau Fire Station. It is currently equipped with three screw
pumps (two duty and one standby) with existing pumping capacity of 29,376 m3/d
(340 L/s). Upon completion of the
Project, it will be increased to a capacity of 42,336 m3/d (490
L/s).
2.1.6
The upgrading works of Pak She
SPS mainly include replacement of pumps with higher pumping capacity and other
Electrical and Mechanical (E&M) equipments, minor modification of existing
pump troughs. Dual power supply or standby power sources, and deodourizing
units will be provided to the upgraded Pak She SPS.
2.1.7
There is an existing 750mm dia. emergency bypass at the Pak She SPS currently connected to the Cheung Chau typhoon
shelter. Under this Project, the emergency bypass from Pak She SPS will be
diverted away from the typhoon shelter by constructing a 750mm dia. bypass pipe
connecting from the existing overflow pipe of the SPS to downstream sewerage
system as presented in Figure 2.5. No sewage emergency discharge from Pak She
SPS into the Cheung Chau typhoon shelter would be anticipated after the
upgrading works.
Sewers works
2.1.8
The proposed sewers works in
Cheung Chau include:
(a) Upgrading of approximately 120 m long existing sewer of size 150 mm
to 400 mm diameter;
(b) Rehabilitation of approximately 160 m long existing sewer of size
525 mm diameter;
(c) Construction of approximately 7,500 m long of new sewers with size
150 mm to 400 mm diameter in village areas by open cut method; and
(d) Construction of approximately 300 m long of new deep sewers with
size Twin 400 mm to Twin 500 mm diameter along Cheung Chau Sports Road and Tung
Wan Road by trenchless method.
2.1.9
Under Part I, Schedule 2 of the
EIAO, the Project consists of the following designated projects:
(a) Upgrading of the existing Cheung Chau STW – under Item F.2 which is Sewage Treatment Works with an installed
capacity of more than 5,000 m3/d and a boundary less than 200 m from
the boundary of a residential area;
(b) Upgrading of the existing Pak She SPS - under Item F.3 which is Sewage Pumping Station with an installed
capacity of more than 2,000 m3/d and a boundary less than 150 m from
the boundary of a residential area; and
(c) Upgrading of the existing Cheung Chau STW – under Item F.4 which
includes an activity for the reuse of
treated sewage effluent from a treatment plant.
Existing Conditions
2.2.1
There is no public sewerage
system for some of the village houses currently in Cheung Chau. Sewage and greywater generated from most of
these village houses are disposed of at septic tanks adjacent, where regular
maintenance is needed. Sewage and
greywater generated from some of the village houses is even directly discharged
into surface drainage system.
2.2.2
Besides, the existing sewage
treatment plant at Cheung Chau is a primary treatment facility and inadequate
to cope with the population growth and future development within the
catchments.
Purpose and Objectives of the Project
2.2.3
The Project is to improve the coastal
water quality to the northwest of Cheung Chau by upgrading of existing sewers
and provision of new sewers where practicable within the catchment, upgrading
of the existing primary treatment plant to a secondary STW and expand the STW
to cope with the population growth and future developments to improve the
hygiene conditions at Cheung Chau.
Without
Project
2.3.1
Most of the village houses will
remain unsewered. Sewage will be
disposed of at septic tanks and required to be cleared manually from time to
time. Hygiene problems will continue to
arise such as odour impacts. Improper
maintenance of septic tanks will also cause problems such as overflow from
septic tanks or soakaway pit, which would cause pollution to nearby areas
and/or streams. Moreover, the sewage treatment plant will remain as primary
treatment level and suffer from insufficient capacity to cope with increased
sewage flows and loads in the future, and consequently deteriorate the coastal
water quality.
With
Project
2.3.2
Public sewers will be provided
to unsewered village houses as far as practicable. Hygiene problems arising from the use of
septic tanks will be largely relieved. Moreover, the sewage treatment level
will be upgraded from primary to secondary and the capacity of the STW will be
expanded to cope with the population growth and future developments. Discharge of low quality effluent to the
receiving water body will be reduced and hence will improve the coastal water
quality of Cheung Chau.
2.4.1
Under the Investigation Stage,
the proposed works for SPS in Cheung Chau include construction of a new Kwun
Yam Wan SPS and upgrading of the existing Pak She SPS.
2.4.2
Kwun Yam Wan SPS was proposed
under the conforming design for conveying sewage from Fa Peng and Chi Ma Hang,
through the low spot area near Kwun Yam Wan, to the existing sewerage system at
Cheung Chau Sports Road.
2.4.3
Due to the close proximity of
the Kwun Yam Wan SPS and Kwun Yam Wan Beach, which is a Gazetted Beach, the
proposed SPS will likely create adverse environmental impacts to beach visitors
and swimmers during both construction and operation if impacts are not properly
controlled. Moreover, the catchment of
the SPS consists of village houses, squatter huts and a camp site, which
contribute to a major population of the catchment, the design flow is
relatively small and will fluctuate with peak flows only occurring at weekends
from the camp sites. These flow conditions
will create potential septicity problems, maintenance and operational
difficulties to the Kwun Yam Wan SPS and its associated rising mains. In addition, the proposed SPS site will
require land resumption, which adds to the uncertainties associated with this
pumping scheme.
2.4.4
Alternatives to the
construction of the Kwun Yam Wan SPS have been investigated:
(a) Reduced Sewerage Provision Option: sewerage works not provided to
catchments upstream of the Kwun Yam Wan SPS;
(b) Exposed and Deep Sewers Option: construction of a section of 220 m
long exposed gravity sewers along hillside and a section of 60 m long deep
sewers with depth between 6 m to 15 m connecting to the existing sewerage at
Cheung Chau Sports Road; and
(c) Deep Sewers Option: Construction of a section of 700 m long gravity
sewers from the Kwun Yam Wan, of which 300 m long are at a depth of 4 m to 8 m
(ground to invert level) along Cheung Chau Sports Road and Tung Wan Road,
connecting to the existing sewerage at Praya Road. It is proposed that
the 300 m long sewers along Cheung Chau Sports Road and
Tung Wan Road to be constructed by trenchless technique.
2.4.5
Preliminary assessment on
sewerage impact and construction methodology had been studied. Among the three alternatives mentioned above,
Option (c) - Deep Sewer Option is recommended as an alternative to the Kwun Yam
Wan SPS construction based on the extent of sewerage catchment, technical
feasibility and ease of maintenance. The
proposed layout of the Deep Sewer Option is shown in Figure 2.3.
2.4.6
The Deep Sewer Option will
eliminate the Kwun Yam Wan SPS and serve the same catchment as that of the SPS
scheme. The diversion of upstream sewage
flows to the deep sewers will eliminate the need to upgrade the existing sewers
along Cheung Chau Sports Road and Tung Wan Road (proposed under the Kwun Yam
Wan SPS Option). With the introduction
of trenchless construction method under the Deep Sewer Option, the extent of
road opening works along the Cheung Chau Sports Road and Tung Wan Road could be
reduced.
2.4.7
The major drawback of the Deep
Sewer Option is the difficulty in maintenance due to the deeper sewer alignment
beneath Cheung Chau Sports Road and Tung Wan Road. The gradient of the deep sewer is constrained
by the existing invert level of the downstream connecting sewerage, and results
in a slack gradient. However, by introducing the use of HDPE
pipes and diversion of sewage flow from existing Nam She Tong SPS, a minimum
velocity of 0.75 m/s could be reached along the sewers from Kwun Yam Wan to
Cheung Chau town centre. Twin sewers would be provided to facilitate
future maintenance. Rehabilitation of the trunk
sewers along Praya Street is also proposed to enhance
the hydraulic performance of the pipes.
2.4.8
Table 2.1 provides the environmental benefits and dis-benefits of the
proposed Kwun Yam Wan SPS Option and the Deep Sewer Option.
Table
2.1 :
Environmental Benefits and Dis-Benefits of Alternative Options
|
Options
|
Environmental Benefits
|
Environmental
Dis-Benefits
|
Other Considerations
|
|
Kwun Yam Wan
SPS Option
|
Ÿ Relatively shallower sewers and rising
mains will be constructed along Tung Wan Road, which can be completed within a
shorter duration. Hence nuisance to
the sensitive receivers would be of shorter period.
|
Ÿ The
proposed SPS may have potential adverse environmental impacts such as dust
during construction; and emergency discharge, visual impacts and odour to the swimmers nearby during operation.
Ÿ Approximately
15% of the population served by the proposed SPS is contributed by two camp
sites in Fa Peng (population is categorised as institution). This would
contribute to about 32% sewage inflow to proposed sewage pumping
station. As this flow from the camp
sites would fluctuate significantly, potentially between zero flow during
weekdays, to a high flow during holidays, this will create operation and
maintenance problems to the proposed SPS and rising mains. Sewage would remain stored in the pumping
station wet well and rising main until subsequent inflows reach the SPS
before triggering the pump to operate, which may cause septicity issue.
Ÿ Open-trench
excavation is required for proposed rising main and existing sewer upgrading
works. Noise nuisance will affect all
sensitive receivers along the entire works alignment.
|
Ÿ Construction
difficulties will be encountered for the construction works at Kwun Yam Wan
Beach area with limited space.
Ÿ The
proposed Kwun Yam Wan SPS is located on private lot where land resumption and
site clearance is required.
|
|
Deep Sewer Option
|
Ÿ Potential
adverse environmental impacts (such as water quality of emergency discharge,
visual and odour) to the swimmers in Kwun Yam Wan Beach can be eliminated.
Ÿ No
operation and additional maintenance for the SPS is required.
Ÿ Excavation
is only required at the working pit locations, hence localised construction
nuisance to the sensitive receivers near the working pits only.
Ÿ Comparatively
less excavated materials will be generated.
|
Ÿ Noise
impacts at the pit locations during construction.
|
Ÿ Relatively
more difficult in maintenance of the deep sewer.
Ÿ Diversion
of upstream flow to the deep sewers so that no upgrading of existing sewers
along Tung Wan Road and Praya Road is required.
|
2.5.1
Trenchless construction
techniques are proposed for the construction of pipes beneath Cheung Chau
Sports Road and Tung Wan Road. Both
trenchless techniques by Tunnel Boring Machine (TBM) and Hand-Shield Excavation
– Segmental Method are feasible in Cheung Chau but as discussed below, the
Segmental Method is more suitable for Cheung Chau.
2.5.2
TBM method for the construction
of a single small diameter sewer is considered technically feasible in Cheung
Chau. The major concern for TBM method
is the heavy TBM equipment which creates transport logistical difficulties
within Cheung Chau. Furthermore, the large
equipment will also occupy large working space to house the slurry tank and
electricity generator, which would be a nuisance to the public, in particular
along Cheung Chau Sports Road and Tung Wan Road, which are busy. Construction of twin pipes is also considered
impractical with TBM technique because separation distances between the pipe
construction is necessary and results with the need to have larger corridor
widths and larger construction areas, which is limited on Cheung Chau.
2.5.3
Segmental Method is a manual
excavation method which involves a shield head to be launched into the
ground. The erection of the
pre-fabricated segmental rings is done within the shield head. The rock/spoil is excavated manually from the
tunnel face and transferred to ground level to be disposed of offsite. Wastewater generated shall be properly treated
by desilting tanks before discharged (similar to all other excavation
works). Relatively smaller working space
and smaller machines would be required for Segmental Method. It also enables twin gravity pipes to be laid
within trenches. The major drawback for
Segmental Method is the slow progress with excavation in rock, but it is
expected that through multiple workfronts and proper sequencing of works, this
programme implication would be resolved to not affect the overall Project
completion.
2.5.4
Table 2.2 provides the environmental benefits and dis-benefits
of the Hand-Shield (Segmental Method) and the TBM construction Method.
Table 2.2 : Environmental Benefits and Dis-Benefits
of Alternative Construction Methods
|
Options
|
Environmental Benefits
|
Environmental Dis-Benefits
|
|
Hand Shield Excavation (Segmental Method)
|
Ÿ
Less environmental nuisance to the public
during construction as it requires much less working space when compared with
TBM method.
Ÿ
Launching pit size is about
2.5 m x 3 m.
Ÿ
No slurry tank and electricity generator is
required.
|
Ÿ
Longer period of environmental disturbance at
the workfronts due to slow construction progress: 1m per day in soil and 1m
per 6 days in rock.
Ÿ
Multiple workfronts and proper sequencing of
works are required, which may give rise to more nuisance.
|
|
TBM Method
|
Ÿ
Jacking head returns back to launching
pit. Construction works can be speeded
up and hence reducing the period of environmental disturbance.
|
Ÿ
Nuisance to the public as large working space
is required for placing the machine, the slurry tank and the electricity
generator. The space required for
launching pit is large. (Approx. 4-6m)
|
2.6
Selected of Preferred Scenario
2.6.1
The Deep Sewer Option is
recommended mainly because it eliminates the need of a new SPS which will have
the potential to cause adverse environmental impacts to the nearby Kwun Yam Wan
Beach.
2.6.2
The Hand Shield Excavation
(Segmental Method) is recommended due to its smaller machine and less space
required. To compensate for the slow
progress, multiple workfronts and proper sequencing of works are required.
2.7.1
The following non-potable
effluent reuse elements are proposed for MBR treated effluent:
(a) Process cleaning water for: screens, grit classifier, membrane
filter press, storm tanks, channels and tanks, floor wash down, etc.; and
(b) On-site toilet flushing.
2.7.2
200m3/d of the
treated effluent would be undergoing chlorination in the disinfection tank
before being conveyed to the treated water storage tank for further
distribution to the effluent reuse units within the STW. The quality of chlorinated effluent for
effluent reuse in this Project is summarized in Table 2.3. This is the effluent reuse standards
recommended in the proposed expansion of Shek Wu Hui STW for off-site toilet
flushing and other non-potable uses. The
recommended standards are more strengthened when compared with the treated
effluent standard recommended for Ngong Ping STW, where the effluent is reused
for off-site toilet flushing and other potential non-potable reuses (such as
irrigation, water features, cooling towers, etc.).
Table 2.3 : Effluent Reuse Standards
|
Water Quality Parameter
|
Unit
|
Ngong Ping STW Effluent Reuse Quality
|
Shek Wu Hui STW Effluent Reuse Quality
|
Recommended Effluent Reuse Quality for Cheung Chau STW
|
|
pH
|
-
|
Not specified
|
6-9
|
6-9
|
|
Residual Chlorine
|
mg/L
|
³ 0.5
|
³ 1
|
³ 1
|
|
E.Coli
|
counts/100 ml
|
< 100
|
Not detectable
|
Not detectable
|
|
Turbidity
|
NTU
|
£ 10
|
£ 5
|
£ 5
|
|
Biochemical Oxygen Demand (BOD5)
|
mg/L
|
£ 10
|
£ 10
|
£ 10
|
|
Dissolved Oxygen
|
mg/L
|
³ 2
|
³ 2
|
³ 2
|
|
Total Suspended Solid (TSS)
|
mg/L
|
£ 10
|
£ 5
|
£ 5
|
|
Ammonia Nitrogen (NH3N)
|
mg/L
|
£ 1
|
£ 1
|
£ 1
|
|
Colour
|
Hazen Unit
|
£ 20
|
£ 20
|
£ 20
|
|
Synthetic Detergents
|
mg/L
|
£ 5
|
£ 5
|
£ 5
|
|
Threshold Odour Number (TON)
|
-
|
Not specified
|
£ 100
|
£ 100
|
2.7.3
The schematic diagram of
effluent reuse is presented in Figure
2.4. A chlorine dosing system in the form of
sodium hypochlorite with contact time of about 30 minutes will be
installed. The remaining portion of
treated effluent without chlorination will be discharged via outfall. The
chlorination process will cease when its quantity is monitored to reach a
pre-set level to avoid over generation of chlorinated treated effluent. In-house monitoring would be performed by STW
Operators at the discharge point to ensure the residual chlorine level in
discharged effluent is less than 1mg/L as stated in the Technical Memorandum on
Standards for Effluent Discharged into Drainage and Sewerage Systems, Inland
and Coastal Water (TM) for Marine Waters of the
Southern Water Control Zone.
2.7.4
Small amount of sodium
hypochlorite solution (<250L) will be stored on-site. Such amount could be exempted from licensing
requirements under the Dangerous Goods Ordinance (Cap 295) and is far less than
that planned to be stored in the Stonecutters Island STW (1.8 million L of
sodium hypochlorite) for the operation of the disinfection facilities in the
Harbour Area Treatment Scheme (HATS), storage of which has been concluded to
present an “acceptable” risk in the quantitative risk assessment of the
approved EIA study for HATS.
2.7.5
Sodium hypochlorite is
classified as a Category 4 poisonous substance under the Dangerous Goods
Ordinance (Cap 295). They are not acutely toxic, flammable, or explosive
substances, but hazardous gas would be generated if they were accidentally
mixed with incompatible chemicals. Also,
the use of these chemicals in the treated effluent reuse system would not constitute a
potentially hazardous installation in accordance with EPD’s ProPECC PN 2/94
Potentially Hazardous Installation.
2.8.1
The
effluent reuse is expected to reduce the amount of potable water demand
required for the on-site STW operation, thereby providing an environmental
benefit. Since there is no off-site
effluent reuse, no potential health impacts to general public on effluent reuse
is anticipated.
2.8.2
The treated
effluent is to undergo a chlorination treatment process before being conveyed
to the point of storage and usage.
Chlorination is to minimize bacterial growth and contamination during
the water transmission. The recommended
residual chlorine level in Shek Wu Hui STW is 1 mg/L for reducing odour and bacterial growth.
2.8.3
The process for the generation
of chlorinated treated effluent will cease when its quantity is monitored to
reach a pre-set level. In-house
monitoring would be performed by STW Operators at the discharge point to ensure
the residual chlorine level in discharged effluent is in compliance with the
discharge requirements. No adverse water
quality impacts are therefore anticipated from the normal operation of the
effluent reuse system.
2.8.4
To avoid the
potential health and hygiene problems associated with
possible incorrect pipe connections, pipes for the treated effluent would be
specially arranged to differentiate them from potable water pipes. For example, pipes for the treated effluent
are colour-coded, clearly labelled with warning signs and notices, and/or sized
differently, so that physical connection of the treated effluent pipes with
potable water fittings would be unlikely.
The effluent reuse system will also be provided with safe guard system
to avoid arbitrarily contact from human.
Appropriate provisions would also be incorporated into the operation and
maintenance manual to prevent possible incorrect pipe connections. With proper preventative measures in place,
health and hygiene impacts are not anticipated to occur during the normal
operation of the effluent reuse system.
2.9.1
The tentative implementation
schedule for different works packages is presented in Table 2.4 below.
Table 2.4 : Tentative Implementation Schedule for
Different Works Packages
|
|
Package 1
Cheung Chau STW and Pak She SPS upgrading
|
Package 2
Cheung Chau Sewers Works
|
|
EIA Endorsed
|
Nov 2013
|
|
Scheme Gazette under WPC(S)R
|
-
|
May 2014
|
|
Scheme Authorization
|
-
|
Aug 2014
|
|
Tender Gazette
|
May 2014
|
Apr 2015
|
|
Contract Commencement
|
Sep 2014
|
Aug 2015
|
|
Contract Completion
|
Mar 2019
|
Mar 2019
|
2.10
Public Consultations
2.10.1
Project Profile had been
prepared in December 2009 for application of Environmental Impact Assessment
Study Brief under EIAO. No adverse
comments had been received from the public.
2.10.2
Consultations had been
conducted with Cheung Chau Rural Committee and Islands District Councilor
regarding the proposed works under this Project. Three consultation meetings
had been arranged in June 2011 and general supports on the Cheung Chau Sewerage
Works were gained from the forum.
2.11
Project Interface / Concurrent
Projects
(a)
“Improvement of Fresh Water
Supply to Cheung Chau - Design and Construction” undertaken by WSD Design
Division;
(b)
“Replacement and Rehabilitation
of Water Mains Stage 3, Mains On Hong Kong and Islands – Investigation, Design
and Construction” untaken by WSD CM Division;
(c)
“Replacement and Rehabilitation
of Water Mains Stage 4, Mains On Hong Kong and Islands – Investigation, Design
and Construction” untaken by WSD CM Division; and
(d)
“Improvement to Existing Roads
and Drains in Cheung Chau Old Town, Remaining Engineering Works, Stage 3,
Cheung Chau” undertaken by CEDD/HK&I.
2.11.2
The following discusses the
potential interface issues between this Project’s components and the projects
mentioned in Section 2.11.1.
Improvement of Fresh Water Supply to Cheung Chau - Design and
Construction
2.11.3
Based on the information
provided by WSD, the captioned Agreement is currently under detailed design
stage. Construction will commence in mid
2013 and complete in end 2015. There is
potential interface with the sewers works proposed under this Project at Cheung
Chau Tai Kwai Wan.
2.11.4
A short section of the
land-based watermains at Tai Kwai Wan will be laid and connected to the
existing trunk mains. Close liaison will
be undertaken with the project proponent of the interfacing project to avoid
concurrent works as far as possible. By
avoiding concurrent works and given the short section of the land-based
watermains and the small scale works involved, adverse cumulative environmental
impact is not expected.
Replacement and Rehabilitation of Water Mains Stage 3 and Stage 4, Mains
on Hong Kong and Islands - Investigation, Design and Construction
2.11.5
Based on the information
provided by WSD, Stage 3 works have been completed by end 2012. No direct interface will be expected from the
two projects.
2.11.6
The construction of Stage 4
works commenced in October 2012 and is anticipated for completion in end
2015. The potential interface with the
sewers works under this Project is at Cheung Chau – Tai Shek Hau, Tung Koon San
Tsuen, Round Table 2nd Village and Round Table 3rd Village.
2.11.7
Close liaison will be
undertaken with the project proponent of the interfacing project to avoid
concurrent works as far as possible. By
avoiding concurrent works and given the short section of the land-based water
main and the small scale works involved, adverse cumulative environmental
impact is not expected.
Improvement to Existing Roads and Drains in Cheung Chau Old
Town, Remaining Engineering Works Stage 3, Cheung Chau
2.11.8
Potential interface between the
proposed sewerage, road and drainage works under CEDD project with this Project
were identified mainly in Cheung Chau Town Centre, Hill Side Road, Kwun Yam Wan
Road, Tai Shek Hau, Lung Tsai Tsuen, Ko Shan Tsuen and Pak She San Tsuen.
2.11.9
Based on the information
provided by CEDD, Stage 3 is currently under detailed design stage and the
construction programme could not be ascertained at time of this EIA Study. However, it has been agreed in principle with
CEDD that any construction works under the two projects within a local area
would be undertaken by only one party as far as practicable. By avoiding concurrent works involved,
adverse cumulative environmental impact is not expected.
Summary - Potential Interfacing Projects During Construction
2.11.10
The interfacing projects that
may have potential to cause cumulative construction impacts are summarized in Table
2.5.
Table 2.5 : Interfacing Projects
|
Interfacing Project
|
Scheduled Construction Period
|
Overlapping Months
|
Potential Cumulative Impacts
|
|
Start
|
Complete
|
|
Improvement of Fresh Water Supply to Cheung Chau
|
Mid 2013
|
End 2015
|
5
|
Yes
|
|
Replacement and Rehabilitation of Water Mains Stage 3, Mains on Hong
Kong and Islands
|
--
|
End 2012
|
--
|
No
|
|
Replacement and Rehabilitation of Water Mains Stage 4, Mains on Hong
Kong and Islands
|
Oct 2012
|
End 2015
|
5
|
Yes
|
|
Improvement to Existing Roads and Drains in Cheung
Chau Old Town, Remaining Engineering Works, Stage 3, Cheung Chau
|
Construction programme not yet confirmed
|
--
|
--
|
2.11.11
Notwithstandingly, continuous
liaison will be conducted with all works department and utilities companies to
ensure adequate phasing with each concurrent project is taken into
consideration, if interfacing does eventually occurs. Cumulative environmental impact will
therefore be eliminated by proper scheduling of works to avoid concurrent
works.