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Environmental Impact
Assessment
for
Proposed Headquarters and Bus Maintenance Depot
in Chai Wan
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Project Consultancy Team:
Ling Chan + Partners Limited
in association with
CH2M HILL (China) Limited
Wong Pak Lam & Associates Limited
Thomas Anderson & Partners Limited
LLA Consultancy Limited
MDA Hong Kong Limited
Edaw Earthasia Limited
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TABLE OF CONTENTS
1. Introduction
1.1 Project Need
1.2 Project
Design & Technical Assessments
1.3 Objectives
of the Assessment
1.4 Public Inputs
1.5 Structures
of the EIA Report
2. Site
selection HistoRy
2.1 Identification
of Alternative Development Sites
2.2 Selection
of Preferred Site
2.3 Required
Technical Assessments of Selected Site
3. Project
Description and key environmental issues identification
3.1 The Subject
Site and its Environs
3.2 Bus Depot
Design
3.3 Implementation
Programme
3.4 Identification
of Key Environmental Issues
4. Air
Quality Impact Assessment
4.1 Introduction
4.2 Assessment
Criteria
4.3 Air
Sensitive Receivers (ASRs)
4.4 Baseline
Condition
4.5 Construction
Dust Emission Impact Assessment
4.6 Vehicular
Emission Impact Assessment
4.7 Environmental
Monitoring & Audit (EM&A) Requirements
4.8 Assessment
Conclusions
5. Noise
Impact Assessment
5.1 Introduction
5.2 Study Area and Noise Sensitive Receivers (NSRs)
5.3 Construction Noise Impact Assessment
5.4 Operational Fixed Noise Impact Assessment
5.5 Operational Off-site Traffic Noise Impact
Assessment
5.6 Conclusion
6. Waste
Management
6.1 Introduction
6.2 Legislation and Guidelines
6.3 Construction Waste Impacts
6.4 Construction Waste EM&A Requirements
6.5 Operational Phase Waste Impact
6.6 Conclusion
7. Land Contamination Prevention
7.1 Introduction
7.2 Baseline Condition
7.3 Potential Land Contamination Sources
7.4 Land Contamination Preventive Measures
7.5 Conclusion
8. Hazard Impact
8.1 Introduction
8.2 Quantitative
Risk Assessment
8.3 Population
Data
8.4 Meteorology
8.5 Local
Topography
8.6 Ignition
Source
8.7 Hazard Events
8.8 Safety
System and Fire Protection/Fighting System Failure
8.9 Summary
of Frequency of Failure Cases Adopted
8.10 Hazard
Occurrence
8.11 Consequence
of Hazard Occurrence
8.12 Consequence
Analysis
8.13 Risk Summation
8.14 Assessment
Finding and Discussion
8.15 Conclusion
9. Landscape
and Visual Impact Assessment
9.1 Introduction
9.2 Landscape Impact Assessment
9.3 Visual Impact
10. Wastewater
Treatment and Disposal Facilities
10.1 Relevant
Standards and Guidelines
10.2 Wastewater
Treatment and Disposal
11. sUMMARY
OF eNVIRONMENTAL OUTCOMEs
11.1 Introduction
11.2 Environmental Benefits
12. Overall
Conclusion
12.1 Introduction
12.2 Key Environmental Issues
12.3 Air Quality Impact Assessment
12.4 Noise Impact Assessment
12.5 Waste
Management
12.6 Land
Contamination Prevention
12.7 Hazard Impact
12.8 Landscape
and visual impacts
12.9 Wastewater
Treatment and Disposal Facilities
12.10 Overall
Conclusion
LIST OF FIGURES
Figure 1‑1 Location
of proposed Headquarters and Bus Maintenance Depot in Chai Wan. 1-5
Figure 2‑1 Locations
the small patches of undeveloped sites (I, II and III) in A Kung Ngam
Industrial Area. Error! Bookmark not
defined.
Figure 2‑2 Locations
of Sites A, B and C in Chai Wan East Industrial Area. Error!
Bookmark not defined.
Figure 3‑1 Outline Zoning Plan No. S/H20/11 (Extract). Error! Bookmark not
defined.
Figure 3‑2 Proposed Locations of Vehicular
Access and Routing Plan. Error!
Bookmark not defined.
Figure 3‑3 Preliminary Floor Layout Plan –
Ground Floor and Upper Ground Floor Plan. Error!
Bookmark not defined.
Figure 3‑4 Preliminary Floor Layout Plan – First Floor
Plan. Error! Bookmark not
defined.
Figure 3‑5 Preliminary Floor Layout Plan – Second Floor
Plan. Error! Bookmark not
defined.
Figure 3‑6 Preliminary Floor Layout Plan – Third Floor
Plan. Error! Bookmark not
defined.
Figure 3‑7 Preliminary Floor Layout Plan – Fourth &
Fifth Floor Plan. Error!
Bookmark not defined.
Figure 3‑8 Cross Section of the Proposed Headquarters and
Bus Maintenance Depot Development Error!
Bookmark not defined.
Figure 3‑9 Preliminary Construction Programme. Error! Bookmark not
defined.
Figure 3‑10 Air
Quality/ Noise Impact Assessments - Boundary of Study Area. Error! Bookmark not
defined.
Figure 4‑1 Location of the Representative Assessment
Points, Air Quality Impact Assessment Error!
Bookmark not defined.
Figure 4‑2 Mitigated 1-hour TSP Concentrations predicted
at 1.5m above Ground, Construction Dust Impact Assessment Error! Bookmark not
defined.
Figure 4‑3 Mitigated 24-hour TSP Concentrations predicted
at 1.5m above Ground, Construction Dust Impact Assessment Error! Bookmark not
defined.
Figure 4‑4 Cumulative 1-hour NO2 Concentrations
predicted at worst-affected height (10m above ground) resulted from open road
& depots emission. Error!
Bookmark not defined.
Figure 4‑5 Predicted 1-hour CO Concentrations predicted at
worst-affected height (10m above ground) resulted from open road & depots
emission. Error! Bookmark not
defined.
Figure 4‑6 Predicted 24-hour RSP Concentrations predicted
at worst-affected height (10m above ground) resulted from open road &
depots emission. Error! Bookmark not
defined.
Figure 4‑7 Predicted 24-hour NO2
Concentrations predicted at worst-affected height (10m above ground) resulted
from open road & depots emission. Error!
Bookmark not defined.
Figure 5‑1 Locations of Representative
Assessment Points selected for Noise Impact Assessment Error! Bookmark not
defined.
Figure 5‑2 Location
of the 6m high noise barrier recommended during the construction phase at the
western boundary of the site along Shing Tai Road. Error!
Bookmark not defined.
Figure 5‑3 Preliminary
Design of the Temporary Noise Barrier erected at the western site boundary
along Shing Tai Road. Error! Bookmark not
defined.
Figure 5‑4 Location
of the recommended 3m High Solid Vertical Wall on the Roof Level of the Bus
Depot Error! Bookmark not
defined.
Figure 8‑1 The
150m Study Area surrounding the Petrol/LPG Filling Station. Error! Bookmark not
defined.
Figure 8‑2 Layout
of a typical Petrol Cum LPG Filling Station. Error!
Bookmark not defined.
Figure 8‑3 Predicted
Societal Risk in the vicinity of the LPG/Petrol Filling Station. Error! Bookmark not
defined.
Figure 8‑4 Predicted
Individual Risk in the vicinity of the LPG/Petrol Filling Station. Error! Bookmark not
defined.
LIST OF TABLES
Table 2‑1 Nearest Distance of Site B
and C from the nearby Sensitive Receivers
Table 4‑1 Hong Kong Air Quality Objectives
Table 4‑2 Representative Assessment
Points
Table 4‑3 Background Air Pollutant
Levels Adopted in the Assessment
Table 4‑4 Maximum 1-hour TSP
Concentrations predicted at the ASRs
Table 4‑5 24-hour Average TSP
Concentrations predicted at the ASRs
Table 4‑6 Maximum 1-hour TSP
Concentrations predicted at the ASRs
Table 4‑7 24-hour Average TSP
Concentrations predicted at the ASRs
Table 4‑8 Year 2018 Traffic Forecast
during the early Morning Peak Leaving
Table 4‑9 Year 2018 Traffic Forecast
during the Nighttime Peak Return
Table 4‑10 2003 Vehicular Emission Factors
Table 4‑11 Predicted Pollutant
Concentrations from Open Road Vehicular Emission
Table 4‑12 Worst-case Bus Flow entering/ leaving the Depot Building
Table 4‑13 Emission Factor for Buses
inside Depot
Table 4‑14 Bus Depot Air Pollutant
Emission Rates
Table 4‑15 Predicted pollutant
concentrations due to emissions from Citybus Depot and NWFB Depot
Table 4‑16 Cumulative Pollutant
Concentrations from Open Road Traffic Emission & Depots Emission
Table 5‑1 Representative Assessment Points selected for
Noise Impact Assessment
Table 5‑2 Noise Limits for Daytime
Construction Activities
Table 5‑3 PME Inventory for Foundation Construction Works
Table 5‑4 Inventory of PMEs during Sheet Piling and Pile Cap Construction
Table 5‑5 Inventory of PMEs during Superstructure Construction
Table 5‑6
Unmitigated Noise Levels
predicted at the RAPs, Leq(30min.)dB(A)
Table 5‑7 Mitigated Noise Level Predicted at the Representative NSRs (with
silenced PMEs)
Table 5‑8 Predicted Noise Level at the Representative NSRs (with silenced
PME, phasing of activities and reduction in number of PME operating
simultaneously)
Table 5‑9 Mitigated Noise Levels at the RAPs (with silenced PME, phasing of
activities and reduction in number of PME, fixed noise barrier and machinery
enclosures)
Table 5‑10 Area Sensitivity Ratings of NSRs
Table 5‑11 Identified Noise Sources associated with the
Depot Operation
Table 5‑12 Predicted Noise Levels at the NSRs due to Depot
Operation
Table 5‑13 Year 2003 Traffic Forecast
Table 5‑14 Year2018 Traffic Forecast
Table 5‑15 Predicted Noise Levels for the “with bus depot” and “without bus
depot”scenarios during early morning peak hour (0530 to 0630), L10(1-hr)
Table 5‑16 Predicted Noise Levels for the “with bus depot” and “without bus
depot”scenarios during mid-night peak hour (2300 to 0000), L10(1-hr)
Table 5‑17 Predicted Noise Levels for the “with bus depot” and “without bus
depot”scenarios during early morning peak hour (0530 to 0630), L10(1-hr)
Table 5‑18 Predicted Noise Levels for the “with bus depot” and “without bus
depot”scenarios during mid-night peak hour (2300 to 0000), L10(1-hr)
Table 6‑1 Likely Types and Estimated
Quantity of Chemical Wastes to be produced from Depot Operation
Table 8‑1 Safety Valves associated with Pipelines
On-site
Table 8‑2 Design Capacity of the Local Road Carriageways
adopted in the QRA study
Table 8‑3 Most Frequent Wind Speed-Stability Class
Combination
Table 8‑4 Identified Failure case of the LPG
Installation
Table 8‑5 Summary of Spontaneous Failure Cases
and their Frequency of Occurrences
Table 8‑6 Underground Vessel Loading Failure
Cases and their Frequency of Occurrences
Table 8‑7 Underground Vessel Loading Failure
Cases and their Frequency of Occurrences
Table 8‑8 External Event and their Frequency of
Occurrences
Table 8‑9 Failure Rates of Various Safety
Systems
Table 8‑10 Fire Fighting System Failure Cases
and their Frequency of Occurrences
Table 8‑11 Summary of Frequency of
Failure Cases
Table 8‑12 Estimated Failure Rates for
Identified Representative Release Outcomes
Table 8‑13 Release Rate Model Input and Output
Table 8‑14 Hazard Event Outcome for
Representative Release Event
Table 8‑15 Hazard Consequence Outcome Frequency
Table 8‑16 Fatal Radiation Exposure Levels (From Probit)
Table 8‑17 Fireball/BLEVE Model Input and Output
Table 8‑18 Release Rate for Liquid Discharge
Table 8‑19 Jet Flame Model Input and Output
Table 8‑20 Dispersion Model Input and
Output
Table 8‑21 Events contributed to PLL
Table 9‑1 Summary of the Implementation for the
Transplanting Works
Table 11‑1 Environmentally Sensitive Areas and Population
Protected
LIST OF APPENDICES
Appendix 1-1 EIA Study Brief
Appendix 4-1 Worksheet showing Calculation of Dust Emission
Rates, Construction Dust Impact Assessment
Appendix 4-2 A typical FDM result file, Construction Dust
Impact Assessment
Appendix 4-3 Locations of the Existing and Committed Road
Carriageways near to the Proposed Bus Depot
Appendix 4-4 Typical CALINE4 result files, Vehicular Emission
Impact Assessment
Appendix 4-5 Spreadsheet showing the Calculation of Depot
Pollutant Emission Rates
Appendix 4-6 Typical ISCST3
Result Files, Depot Pollutant Emission (NO2,
CO, RSP)
Appendix 5-1 Typical
Calculation Worksheet – Unmitigated Scenario, Construction Noise Impact
Assessment (1, 2, 3,
4, 5,
6, 7,
8, 9,
10, 11, 12)
Appendix 5-2 Typical
Calculation Worksheet – Mitigated Scenario 1, Construction Noise Impact
Assessment (1, 2, 3,
4, 5,
6, 7,
8, 9,
10, 11, 12)
Appendix 5-3 Typical
Calculation Worksheet – Mitigated Scenario 2, Construction Noise Impact
Assessment (1, 2, 3,
4, 5,
6, 7,
8)
Appendix 5-4 Typical
Calculation Worksheet – Mitigated Scenario 3, Construction Noise Impact
Assessment (1, 2, 3,
4, 5,
6)
Appendix 5-5 Typical
Calculation Worksheet, Depot Noise Impact Assessment (1, 2,
3, 4,
5, 6,
7)
Appendix 5-6 Traffic Forecast
Endorsement (1, 2, 3)
Appendix 5-7 Detailed Traffic
Noise Modelling Results (1, 2, 3,
4, 5,
6,7,
8, 9,
10, 11, 12,
13, 14, 15,
16)
Appendix 8-1 Fault Tree Analysis
Appendix 8-2 Event Tree Analysis
Appendix 9-2 Drawings showing
the landscape proposal and design concept to avoid potential visual impact (1, 2, 3, 4, 5, 6, 7)
1.
Introduction
1.1
Project Need
1.1.1
Citybus Limited (Citybus) is one of the major bus services
operators in Hong Kong. To date, it
still does not have its own permanent bus depot. The reliance of the company’s
engineering and maintenance services on temporary depots build on short term
tenancy sites that need to be demolished after temporary use has proven over
the past years not to be a preferable practice. The need to decommission the temporary depot at Aldrich Bay in
near future will create an immediate problem for the company. It would be difficult for Citybus to
maintain its quality bus services to the Hong Kong public in the lack of stable
engineering and maintenance facilities.
1.1.2
Citybus currently operates about 90 routes with a fleet of
about 790 buses on the Hong Kong Island.
While over 400 buses are serving routes in Southern District, some 300
buses are for routes running in the Eastern and Central Districts. Besides, around 50 buses are running on
cross-harbour routes. The daily
servicing of these buses requires depot facilities for refueling, maintenance,
repairing, washing, coin collection and transfer of octopus databank data, etc.
1.1.3
Buses running in the Southern District are currently served by
the bus depot at Ap Lei Chau. A
permanent depot facility is needed in the Eastern District to serve the other
bus routes running on the Hong Kong Island.
With consideration of alternative sites as described in details in
Section 2, a suitable development site of sufficient size was selected with the
relevant Government departments for construction of the proposed bus
depot.
1.1.4
A Traffic Impact Assessment (TIA) was conducted for the
proposed bus depot and approved by the Authority. The TIA study assessed the potential traffic impact of the
proposed bus depot on the adjacent road networks in terms of junction capacity
and bus queue length. Traffic
generation from other future developments, including the New World First Bus
(NWFB) Permanent Depot, was taken into account in the TIA study. The Final TIA Report was accepted by
Transport Department in May 2001.
1.2
Project Design & Technical Assessments
1.2.1
A consultancy team led by Ling Chan + Partners Limited (LCP)
was commissioned by Citybus in December 2000 to study the architectural design
and engineering requirements of the proposed development. CH2M HILL (China)
Limited (formerly known as EHS Consultants Limited) has been commissioned by
Citybus as a sub-consultant of LCP to carry out an EIA Study for the proposed
bus depot development. Issues on
Landscape and Visual Impacts were addressed by EDAW Earthasia Ltd. (EDAW) and
LCP.
1.2.2
Architectural, engineering and traffic design of the
development were developed by LCP, Wong Pak Lam & Associates Ltd. (WPL),
Thomas Anderson & Partners Ltd. (TAP), LLA Consultancy Ltd. (LLA), EDAW and
MDA Hong Kong Ltd. through a series of design co-ordination meetings with
Citybus. The team also provided input
to the EIA study in the relevant areas of their expertise. Inputs on the traffic forecast aspect and
engineering in the EIA study were provide by LLA, WPL and TAP.
1.2.3
According to Part 1 Schedule 2 Section A.6(Roads, railways and
depot) of the EIA Ordinance (EIAO), a transport depot located in less than 200m
from the nearest boundary of an existing or planned residential area and educational
institution is classified as a Designated Project. As the closest distance between the proposed bus depot and the
Hong Kong Institute of Vocational Education (Chai Wan) and Tsui Wan Estate is
about 80m and 165m respectively, the project is classified as a Designated
Project. An Environmental Permit issued
by the Director of Environmental Protection (DEP) is required prior to the
construction and operation of the proposed bus depot.
1.2.4
An application (No: ESB-065/2001) for an Environmental Impact
Assessment (EIA) Study Brief under Section 5(1) of the EIAO was submitted to
DEP on 19th January 2001 with a Project Profile. A Study Brief {No.
ESB-065/2001} was issued by the Authority to the applicant (Citybus) under
Section 5(7)(a) of the EIAO on 5th March 2001 for the preparation of
the EIA report. Appendix 1-1 presents
the EIA Study Brief.
1.2.5
This EIA report is prepared in accordance with the
requirements stated in the Study Brief. An Environmental Permit will only be
issued by DEP for the construction and operational of the project after the
approval of the EIA Report.
1.3
Objectives of the Assessment
1.3.1
The main objective of this EIA study is to provide information
on the nature and extent of the potential environmental impacts arising from
the construction and operation of the proposed bus depot and related activities
taking place concurrently. The study will provide information for DEP’s
decisions on:
(i)
the
overall acceptability of any adverse environmental consequences that are likely
to arise as a result of the proposed project;
(ii)
the
conditions and requirements for the detailed design, construction and operation
of the proposed project to mitigate adverse environmental consequences wherever
practicable; and
(iii)
the
acceptability of residual impacts after the proposed mitigation measures are
implemented.
1.3.2
The objectives of this EIA study, as stated in Section 2.1 of
the Study Brief, are as follows:
(i)
to
describe the proposed project and associated works together with the
requirements for carrying out the proposed project;
(ii)
to
consider alternative site(s) and to compare the environmental benefits and
dis-benefits of each of the site in selecting a preferred site;
(iii)
to
identify and describe the elements of the community and environment likely to
be affected by the proposed project, including both the natural and man-made
environment;
(iv)
to
identify and quantify emission sources and determine the significance of
impacts on sensitive receivers and potential affected uses;
(v)
to
propose the provision of mitigation measures so as to minimize pollution,
environmental disturbance and nuisance during construction and operation of the
project;
(vi)
to
identify, predict and evaluate the residual (i.e. after practicable mitigation)
environmental impacts and the cumulative effects expected to arise during the
construction and operational phases of the project in relation to the sensitive
receivers and potential affected uses;
(vii)
to
identify, assess and specify methods, measures and standards, to be included in
the detailed design, construction and operation of the project which are
necessary to mitigate environmental impacts and to reduce them to acceptable
levels;
(viii)
to
investigate the extent of the secondary environmental impacts that may arise
from the proposed mitigation measures and to identify the constraints
associated with the mitigation measures recommended in the EIA study as well as
the provision of any necessary modification; and
(ix)
to
design and specify the environmental monitoring and audit requirements, if
required, to ensure the implementation and the effectiveness of the
environmental protection and pollution control measures adopted.
1.4
Public Inputs
1.4.1 During
the public inspection period of the Project Profile, public inputs and comments
were received on the project under the EIA Process. The key concerns of some members of the Eastern District Board
received were discussed during the Board meeting on 12 February 2001. The key environmental issues of interest in
relation to the EIA study are summarized below:
·
Potential
air quality impact on nearby sensitive receivers, including Tsui Wan Estate
during the operational phase;
·
Potential
traffic noise impact on Heng Fa Chuen, Tsui Wan Estate and Yue Wan Estate from
bus movement on the road carriageways in the vicinity of the bus depot,
especially traffic noise from Wing Tai Road;
·
Potential
water quality impact on the cargo handling basin;
·
Wastewater
and waste management (including chemical waste) during the operational phase;
·
Potential
cumulative environmental impact from the operation of two bus depots and other
future developments in the area; and
·
Members
agree with the project proponent that a permanent bus depot is needed but
consider that the possibility to locate the bus depot at other district should
be considered.
1.4.2 Potential
concern on these environmental factors has been taken into account in the
study.
1.5
Structures of the EIA Report
1.5.1
This section describes the background, project needs, and
objectives of the EIA study. The site
selection history is described in Section 2.
Design of the proposed development and the identified key environmental
issues are described in Section 3.
Sections 4 to 10 focus on each of the key environmental aspects, and
present the assessment criteria, approach/ methodologies, findings, and
recommended mitigation measures, if necessary. Section 11 presents a summary of
environmental outcomes and the overall conclusion of the EIA study.
1.5.2
The content in Sections 2 through 11 are listed below:
· Section 2 Site Selection History
– describes the site selection process that has gone through with the relevant
Government departments in identifying the subject site for the bus depot
development;
· Section 3 Project Description and
Key Environmental Issues Identification – the subject site and its
environs, preliminary design of the bus depot, the planned implementation
programme, and the key environmental issues identified are described under this
section;
· Section 4 Air Quality Impact
Assessment – presents the construction phase air quality impact assessment,
and operational phase vehicular emission impact assessment;
· Section 5 Noise Impact Assessment
– presents the construction noise impact assessment, traffic noise impact
assessment and industrial noise impact assessment for the operational phase;
· Section 6 Waste Management
Implications – presents an analysis of waste generation and proposes
management measures for the key waste types during the construction and
operational phases of the project;
· Section 7 Land Contamination
Prevention – describes possible sources of contamination arising from the
future operation of the bus depot, appropriate operational practices, waste
management strategies and precautionary measures;
· Section 8 LPG/ Petrol Filling
Station Hazard Impact – assesses the potential hazard from the
operation of the future LPG/ petrol filling station located to the north of the
site on the proposed bus depot;
· Section 9 Landscape and Visual
Impacts – describes the landscape mitigation proposal and present the
preliminary design of the bus depot building to achieve visual compatibility
with its environmental context and avoid visual impact;
· Section 10 Sewage Treatment and
Disposal Facilities – describes the design measures to ensure proper sewage
treatment and disposal;
· Section 11 Summary of
Environmental Outcomes;
· Section 12 Overall Conclusion
2.
Site selection HistoRy
2.1
Identification of Alternative Development Sites
2.1.1
For maintaining of a quality service on the Hong Kong Island,
provision of a permanent bus depot in the Eastern District for the refueling,
maintenance and washing of Citybus’ buses running in the Eastern and Central
Districts is needed. The need to
decommission the temporary depot at Aldrich Bay, which is not zoned for
industrial use, aggregated the problem.
Citybus started the dialogue with the relevant Government departments in
early 2000 to express the urgent need for a permanent depot.
2.1.2
Citybus currently operates about 90 routes with a fleet of
about 790 buses on Hong Kong Island.
While over 400 buses are serving routes in Southern District, some 300
buses are for routes running in the Eastern and Central Districts. Besides, around 50 buses are running on
cross-harbour routes. The daily
servicing of these buses requires depot facilities for refueling, maintenance,
repairing, washing, coin collection and transfer of octopus databank data, etc.
2.1.3
Operationally, Citybus needs two permanent bus depots. Location-wise, it would be more efficient
and environmental friendly to have one depot in the Eastern District and
another in the Southern District. As a
significant portion of buses are heading towards the Central District from
Eastern District when the bus service commences early in the morning, and
returning from Central District to Eastern District for parking, establishment
of a bus depot in the Eastern District will minimize the travelled routes,
distance and time between the bus depot and the various bus terminuses. The establishment of a new bus depot in
other districts may affect Citybus’ existing operation in serving the
public. The operational needs of the buses
running in the Southern District are currently met by the depot facility at Ap
Lei Chau. A permanent depot facility in
the Eastern District is in demand after the decommissioning of the temporary
bus depot in Aldrich Bay.
2.1.4
Taking into consideration the operational requirements of the
multi-storey bus depot in terms of the driveway and ramp system with 15-m
turning radius, and areas required for bus parking, maintenance bays, sunken
pits, workshops, storage areas, staff changing rooms, etc., the minimum size of
the site needed for the construction of a multi-storey bus depot was identified
to be about 1ha.
2.1.5
Bus depots are preferably to be located within industrial
areas to ensure that the landuses in its proximity are compatible. Industrial area in the Eastern District is,
however, extremely rare. During the
site selection process, Planning Department (PlanD) advised that in the Eastern
District, undeveloped industrial areas were only available in Chai Wan East
Industrial Area and A Kung Ngam Industrial Area in Shau Kei
Wan.
2.1.6
Most industrial sites in A Kung Ngam have already been
developed, leaving only three small separate and unformed sites with a site
area of about 920m2, 1800m2 and 1900m2. Figure 2-1 presents the locations of these
separate and undeveloped industrial sites (I, II and III) as shown in the Draft
Shau Kei Wan Outline Zoning Plan (No. S/H9/10).
2.1.7
These unformed industrial sites in A Kung Ngam are too small
for the construction of the proposed multi-storey bus depot. Even the total
area of these undeveloped sites is only about 4,600m2 which cannot
meet the minimum site area required for the design and construction of the bus
depot. Besides, development of the bus
depot on these sites will require resumption of private properties which may not
be feasible.
2.1.8
The existing China Motor Bus (CMB) depot located at Chai Wan
Road will be rented by Citybus for temporary use after decommissioning of its
existing temporary bus depot at Aldrich Bay until the planned completion of the
new depot in mid 2003. The CMB depot
site has been rezoned as a Comprehensive Development Area (CDA) for
redevelopment. Further use of the site
as a bus depot is therefore not preferable.
Besides, there are numerous existing residential buildings located in
close proximity to the existing bus depot at Chai Wan Road. Longer-term use of the site as a permanent
bus depot is not a preferred option from an environmental viewpoint given the
close proximity of the existing bus depot to the nearby sensitive receivers.
2.1.9
The site selection process confirmed that there are no
available industrial sites in the Eastern District other than the industrial
sites in Chai Wan East Industrial Area.
2.1.10
A 0.78 hectare site located to the immediate south of New
World First Bus Depot was initially identified for consideration. The site was
rejected as the site area involved cannot satisfy the minimum site area
requirement for a multi-storey bus depot.
Figure 2-2 shows the location of the site (Site A).
2.2
Selection of Preferred Site
2.2.1
Two candidate sites, Site B and Site C, located within the
Chai Wan East Industrial Area were identified and considered with the
Government departments during the site selection process. Both sites have a similar site area of approximately
1 ha. It was identified that these were
the only available sites within the industrial area that could meet the site
area requirement of the bus depot.
Figure 2-2 shows the locations of these alternative sites – B and C in
the Draft Chai Wan Outline Zoning Plan (OZP) No. S/H20/11 (Extract). The environmental benefits and dis-benefits
of these alternative sites have been considered and compared in the selection
of the preferred site in order to avoid potential environmental impact.
2.2.2
The key environmental factors that would have bearing on the
location of the bus depot include air quality and noise associated with the
operation of the bus depot. Site C, the
selected site, is preferred from an environmental viewpoint as it is located
further away from the nearby sensitive receivers of interest. Table
2‑1 presents a comparison of the nearest distance from
the nearby sensitive receivers for the two alternative sites.
Table
2‑1 Nearest
Distance of Site B and C from the nearby Sensitive Receivers
Location
|
Approximate Nearest Separation (m)
|
|
Site B
|
Site C
|
Heng Fa Chuen
|
115
|
390
|
Staff Quarters of
Hong Kong Institute of Vocational Education (IVE) (Chai Wan)
|
110
|
135
|
IVE (Chai Wan)
|
130
|
80
|
Tsui Wan Estate
|
490
|
165
|
2.2.3
It can be noted that the distance separation between the
nearest residential blocks from the bus depot is greater for Site C than for
Site B. Comparing the relative distance
of Site B and Site C from the residential blocks, Site C was identified to be
the preferred site in terms of avoiding potential environmental effects on air
quality and noise associated with the operation of the bus depot.
2.2.4
Although the Hong Kong Institute of Vocational Education (IVE)
(Chai Wan) is located closer to Site C, it is not expected to be in operation
during the hours in the early morning and near mid-night when the bus depot
would be most active.
2.2.5
In addition, it can be noted that Site C is more directly
linked to Island Eastern Corridor, Shun Tai Road, Sheung On Street when
compared with Site B. Traveling distance on Shing Tai Road and the new roads
within the Industrial Area and the associated vehicular emission can be reduced
for buses heading towards Shau Kei Wan or Siu Sai Wan directions for site C
than for Site B.
2.3
Required Technical Assessments of Selected Site
2.3.1
The selection of Site C was a Government departmental
agreement taking into account, as illustrated above, the requirements on site
area of the bus depot, availability of industrial sites in the Eastern District,
the urgent programme of the project, and landuse compatibility including the
environmental factors.
2.3.2
At the Hong Kong District Planning Conference in mid-June
2000, the site C, bounded by the future local road 20/4 to the East and Shing
Tai Road to the West, was selected and agreed in-principle by the Government
departments to be a suitable site for Citybus to further study the design of
its permanent bus depot proposal.
Citybus was required to conduct a Traffic Impact Assessment (TIA) and an
Environmental Impact Assessment (EIA) to assess and confirm the technical
feasibility of the project at the subject site.
2.3.3
The Final TIA conducted by Citybus’ Traffic Consultant
approved by TD in May 2001 confirms the acceptability of the site for the
development of the bus depot from a traffic point-of-view. Traffic generation from other future
developments in the area, including the New World First Bus (NWFB) bus depot
has been taken into account in the TIA study. The findings of this EIA Study
will confirm the environmental acceptability of the project. Potential cumulative environmental impact
has been assessed as appropriate in accordance with the requirements and
methodologies presented in the Technical Memorandum on EIA Process (EIAO-TM).
Mitigation and/or control measures have been identified and recommended where
necessary.
3.
Project Description and key
environmental issues identification
3.1
The Subject Site and its
Environs
3.1.1
The
proposed bus depot is planned to be constructed on an approximately 1 hectare site
located in the Chai Wan East Industrial Area.
The site selection process is described in Section 2. Figure 1-1 shows the location of the site.
3.1.2
A
major portion of the site is currently unoccupied. Highways Department (HyD) is temporarily occupying a southern
portion of the site for a work area until June 2001. A small area at the northern part of the site falls within the
boundary of the NWFB temporary bus depot.
Located at a minimum distance of about 80m to the North-west of the
future bus depot is Hong Kong Institute of Vocational Education (IVE) (Chai
Wan). Lying between the college and the
bus depot site are the MTR railway tracks leading to the Chai Wan Station to
the south and Shing Tai Road. To the immediate North of IVE is its associated
Staff Quarters. Tsui Wan Estate is
situated at more than 165m to the South-west of the site. The nearest residential blocks at Heng Fa
Chuen is located at approximately 390m to the north of the site.
3.1.3
The
site was reclaimed and is zoned for industrial use (“I”) similar to some other
landuses in its vicinity as shown in the latest Draft Outline Zoning Plan (OZP)
No. S/H20/11 gazetted on 20 April 2001.
According to the Notes of the OZP, “Bus Depot” is a column 1 use that no
planning permission from the Town Planning Board is required. Figure 3-1 presents an Extract of the OZP.
Planning Department (PlanD) has advised that in addition to the proposed
bus depot, the Chai Wan East Industrial Area is also planned to accommodate an
Open Space, a Joint Government Departmental Depot, Lorry Park & Motor
Vehicle Repair Workshop, New World First Bus Depot, LPG/ Petrol Filling Station
and Hong Kong Post Super Centre.
3.1.4
The
northern side of the site is planned by the Government for the provision of a
LPG/ petrol filling station, while the Southern side of the site would be the
HK Post Supercentre. At this stage,
only the NWFB depot situated near Chong Fu Road and located at about 135m from
the proposed bus depot is under active construction. The NWFB depot is expected to be completed by year 2002. All other proposed developments in the area
are still at a planning stage without a concrete development programme.
3.1.5
The
proposed Citybus depot will be bound by a future local road – Road 20/4 to the
East and Shing Tai Road to the west.
Other future new roads in the Chai Wan East Industrial Area include Road
20/6 and Road 20/10 as shown in Figure 1-1.
Highways Department (HyD) has advised that the three new roads – 20/4,
20/6 and 20/10 would be completed in December 2002.
3.1.6
The planned
bus routing plan agreed with TD is illustrated in Figure 3-2.The ingress point of the bus depot is planned at Road 20/4, which
is a local road lying away from nearby sensitive receivers. Buses approaching
the depot from Island Eastern Corridor (IEC) will travel via Shing Tai Road
northbound, Road 20/6 and Road 20/4.
There will only be one egress point each located at Shing Tai Road and
Road 20/4 respectively. The egress point
on Shing Tai Road will serve IEC bound buses which will go via Shing Tai Road
southbound and Shun Tai Road. Buses leaving or returning to the depot will not
pass through the section of Shing Tai Road further north of the site leading to
Heng Fa Chuen.
3.1.7
The
20/4 Road egress point is planned for Siu Sai Wan bound buses. It is understood that Wing Tai Road
currently carries high traffic flows during the peak hours. To avoid potential traffic noise impact
attributed to the operation of the proposed bus depot, as agreed with the
Authority, buses commuting between the bus depot and Siu Sai Wan area will be
required to take the route through the future Sheung On Street Extension
(connecting the existing Sheung On Street with the future Road 20/4) under
normal operating conditions (i.e. except for emergency conditions), instead of
allowed to use Wing Tai Road and Shing Tai Road at all time periods. Citybus will require its employees to
strictly follow this requirement when entering/ leaving the bus depot.
3.2
Bus Depot Design
3.2.1
The
proposed bus depot will be constructed in form of a low-rise building occupying
a site area of approximately 1 hectare.
The development will provide spaces for bus parking, maintenance and
office areas. Architectural design of
the development has been developed by the Project Architect – LCP, with input
on the engineering, traffic and environmental aspects provided by the
sub-consultants.
3.2.2
Figures
3-3 to 3-7 present the preliminary ground to fifth floor layout plans of the
bus depot. A cross section of the
building is shown in Figure 3-8.
The bus depot will consist of three stories located at ground floor
(G/F), first floor (1/F) and roof floor (3/F).
As shown on the preliminary plans, the G/F will house approximately 2
refuelling bays, 2 washing bays, 29 sunken pits, 4 brake testers and 5
maintenance bays. The 1/F will provide some 46 maintenance bays for annual
maintenance works. The 3/F (roof) floor will provide about 100 bus parking
areas. The fourth floor (4/F) and fifth
floor (5/F) that will be built at the southern portion of the site only will be
used for office areas. The upper ground
floor (U/G) and second floor (2/F) is a mezzanine floor provided at the
southern part of the site near Road 20/4.
Spare parts storage areas, chemical storage areas and scrap yards/ waste
material stores will be provided on the G/F and 1/F. Taking into account the interface with the future developments
located in its immediate proximity, including the LPG/ Petrol Filling Station
and the Hong Kong Post Super Centre, the northern and southern sides of the bus
depot building are planned to be constructed with a solid concrete facade.
3.2.3
At the
ingress point at Road 20/4, the incoming buses will enter bays 1 and 2 for
refuelling, coin collection, transfer of octopus data to databank, and vehicle
washing. The whole process of the refuelling/ servicing and washing would
normally take about 3 to 5 minutes. If
maintenance is required, the buses will drive into one of the maintenance bays
or sunken pits.
3.2.4
To
facilitate the buses entering directly to the maintenance area, a passing lane
will be provided in parallel to the refuelling/ washing bay lanes. The provision of a passing lane will also
help to avoid the generation of a long queue length of buses waiting to be
serviced and the associated potential traffic impact. The holding area within the bus depot was assessed to be
sufficient to accommodate the bus queue, as confirmed in the approved TIA.
3.2.5
After
the completion of washing procedure, buses will leave the depot for further
servicing, or returning to parking areas located on 3/F of the bus depot or
off-site. On the 1/F, normally a bus under annual maintenance check will have
to station in a maintenance bay for about 5 to 7 days. Bus movements on the 1/F will therefore be
very limited.
3.2.6
The
number of staff working in the bus depot/ maintenance area and offices is
estimated to be about 319 and 201 respectively during daytime (approx. 08:00 to
18:00). In the evening and night-time
(approx. 18:00 to 08:00), some 50 workers are expected to be working at the bus
depot.
3.3
Implementation Programme
3.3.1
Construction works are planned to start near end of 2001 to
meet the urgent demand to have the depot ready for operation in mid-2003. Figure 3-9 shows a preliminary construction
programme. The development is expected
to be completed in mid-2003.
3.4
Identification
of Key Environmental Issues
3.4.1 The
key environmental issues during the construction and operational phases of the
proposed development are identified to include the following:
During
the Construction Phase
·
Potential
construction dust impact on the nearby air sensitive receivers;
·
Potential
construction noise impact from construction activities;
·
Construction
waste management and implications
During
the Operational Phase
·
Potential
vehicular emission impact from buses moving within the depot and running at the
adjacent roads;
·
Potential
traffic noise impact from buses running on the road carriageways in the
vicinity of the depot;
·
Potential
fixed noise impact generated from activities at the bus depot;
·
Undertaking
of land contamination preventive measures;
·
Proper
chemical waste management;
·
Provision
of sewage treatment and disposal
3.4.2 The
EIA Study Brief requires in general a study area of 300m and 500m from the
boundary of the project site with respect to air quality impact assessment and
noise impact assessment, respectively.
Figure 2-10 shows the study area boundary for air quality and noise
impact assessments.
3.4.3 In
addition to the above key environmental issues, the EIA Study Brief requires an
evaluation on the potential hazard impact arising from the operation of the
future LPG/ Petrol Filling Station located on the northern side of the site
(Section 8), Landscape and Visual Impacts associated with the implementation of
the project (Section 9), and an illustration on the Sewage Treatment and
Disposal Facilities (Section 10).
4.
Air Quality Impact Assessment
4.1
Introduction
4.1.1
This section assesses the potential air quality impact
associated with the construction and operational phase of the proposed bus
depot. Air sensitive receivers (ASRs) have been identified and worst case
impact on these receivers have been assessed quantitatively.
4.1.2
Dust generation from construction activities is identified to
be of key interest during construction phase of the project. During the operational phase, vehicular emission
from buses running within the bus depot and on the adjacent roads is the key
focus of the study.
4.1.3
The assessment covers a study area of 500m from the
development site boundary in accordance with the requirements of the EIA Study
Brief.
4.2
Assessment Criteria
4.2.1
The principal legislation regulating air quality in Hong Kong
is the Air Pollution Control Ordinance (APCO) (Cap. 311). Air Quality Objectives (AQOs) are set for
the whole territory which specify statutory concentration limits for various
criteria pollutants and the maximum numbers of times allowed to exceed over a
specified period of time. The AQOs for
Carbon Monoxide (CO), Nitrogen Dioxide (NO2), Total Suspended
Particulates (TSP) and Respirable Suspended Particulates (RSP), which are
relevant to the assessments, are summarised in Table 4‑1.
Table 4‑1 Hong
Kong Air Quality Objectives
Pollutant
|
Pollutants
Concentration (mg/m3)
|
|
Averaging Time
|
|
1 hour (i)
|
8 hours (ii)
|
24 hours (ii)
|
1 year (iii)
|
CO
|
30,000
|
10,000
|
N.A.
|
N.A.
|
NO2
|
300
|
N.A.
|
150
|
80
|
TSP
|
N.A.
|
N.A.
|
260
|
80
|
RSP
|
N.A.
|
N.A.
|
180
|
55
|
(i) Not to be exceeded more than 3 times per year;
(ii) Not to be
exceeded more than once per year;
(iii) Arithmetic
means;
N.B. Concentrations
measured at 298 K and 101.325 kPa (one atmospheric pressure).
4.2.2
In addition to the AQOs, EPD requires under Annex 4 in the
Technical Memorandum on EIA Process (EIAO-TM) issued under the EIA Ordinance an
hourly TSP limit of 500mg/m3 for construction dust impact assessment.
4.2.3
The Air Pollution Control (Construction Dust) Regulation
came into effect since 16 June 1997.
Site formation, construction of the foundation and superstructure of
buildings, road construction works, etc. are classified as “notifiable work”
under the Regulation. Any work which
involves stockpiling of dusty materials, loading, unloading or transfer of
dusty materials, transfer of dusty materials using a belt conveyor system, use
of vehicles, debris handling, excavation or earth moving, site clearance, etc.
are regarded as “regulatory work”. A
Schedule specifying the dust control requirements for a variety of construction
activities is included in the Regulation.
The contractor responsible for a construction site where a notifiable
work and/ or regulatory work is being carried out have to ensure that the work
is carried out in accordance with the Schedule with regard to dust control.
4.3
Air Sensitive Receivers (ASRs)
4.3.1
As stated in Annex 12 of the EIAO-TM, domestic premises and
schools are defined as Air Sensitive Receivers (ASRs). The nearest ASRs situated in the vicinity of
the proposed bus depot within the study area were identified for the air
quality impact assessment. These ASRs
include the IVE (Chai Wan) and its auxiliary Staff Quarters located to the
north-west of the development site, Tsui Wan Estate located to the south of the
development and Heng Fat Chuen situated to the north of the site.
4.3.2
Representative assessment points (A1 to A6) have been selected
for the air quality impact assessment.
The ASRs represented are described in Table 4‑2. Locations of
the representative assessment points are shown in Figure 4-1.
Table 4‑2 Representative
Assessment Points
Ref. No.
|
Location of ASR
|
Closest distance of ASR from bus depot
boundary (m)
|
A1
|
Heng
Fa Chuen
|
390
|
A2
|
Staff
Quarters of Hong Kong Institute of Vocational Education (IVE) (Chai Wan)
|
135
|
A3
|
IVE
(Chai Wan)
|
80
|
A4
|
IVE
(Chai Wan)
|
85
|
A5
|
Tsui
Hong House, Tsui Wan Estate
|
185
|
A6
|
Tsui
Sau House, Tsui Wan Estate
|
165
|
4.4
Baseline Condition
4.4.1
The existing major air pollution sources in the study area are
expected to be open road traffic emission from major road carriageways (e.g.
Island East Corridor).
4.4.2
Annual average concentrations of nitrogen dioxide (NO2)
and respirable suspended particulate (RSP) recorded by EPD’s monitoring station
in Eastern district for the year 1999 have been used as background pollutant
concentrations in the study area. Although the number of monitoring records for
NO2 for Eastern monitoring station is below the minimum data
required within a quarter, the concentration of 66mg/m3 was found
to be comparable with the concentration at Tsuen Wan which have similar
landuses.
4.4.3
For carbon monoxide (CO) and total suspended particulate (TSP) which has no published data available
in the study area, EPD’s records from the Tsuen Wan monitoring station in 1999
has been adopted. Table 4‑3 summarises the background concentrations of CO, NO2,
and RSP adopted in the assessment for the purpose of evaluating the cumulative
air quality impact.
Table
4‑3 Background Air Pollutant Levels Adopted
in the Assessment
Air Pollutant
|
Annual Average Concentration (mg/m3)
|
CO
|
1177
|
NO2
|
66
|
TSP
|
79
|
RSP
|
47
|
Note : Background
concentrations of CO, NO2 and RSP in the study area has been assumed
based on reported data given in “Air Quality in Hong Kong, 1999” published by
EPD.
4.5
Construction Dust Emission
Impact Assessment
Introduction
4.5.1
The major air quality impact of concern during the
construction phase will be potential dust emission impact on nearby ASRs.
Unacceptable impacts from the criteria pollutants - nitrogen oxides (NOx),
sulphur dioxide (SO2), and carbon monoxide (CO) are unlikely as
significant emissions are not anticipated. Emission from diesel trucks for the
haulage of materials and construction plants will contain high percentage of
smoke particulate and unburned hydrocarbons in comparison with petrol driven
vehicles. However, as the anticipated number of construction plants associated
with the construction works will be limited, significant impact on the existing
air quality is not envisaged.
Dust Emission Sources
4.5.2
Based on the nature of the construction, major dust emission
sources associated with the construction activities are expected to arise from
excavation, material handling and vehicle movement on unpaved haul roads during
the foundation construction stage. The
corresponding dust emission rates associated with these activities have been
worked out by making reference to the typical emission factors reported in the
Compilation of Air Pollutant Emission Factors (AP-42) 5th Edition
published by U.S. Environmental Protection Agency (USEPA).
à
Excavation activities - dust emission from excavation has
been estimated by making reference to the emission factor given in Section 13.2.4
of USEPA AP-42. Dust emissions have
been estimated on a per excavator basis with consideration of typical
excavation rate, number of excavator involved, etc. to simulate a
representative scenario;
à
Material handling - potential dust emission from loading/
unloading activities of excavated material have also been predicted by making
reference to Section 13.2.4 of USEPA AP-42.
Dust emissions from loading/ unloading have been estimated on a per
truck basis with consideration of the capacity of each truck, and the estimated
number of trucks to simulate a representative scenario.
à
Vehicle movement on unpaved haul
roads - dust
emission from traffic movement on unpaved haul roads have been estimated by
making reference to Section 13.2.2 of USEPA AP-42, with consideration of no. of
trucks, typical vehicle speed, weight, number of wheels, etc.
4.5.3
A worksheet showing the calculation of dust emission rates
from each activity is presented in Appendix 4-1 for reference.
4.5.4
Foundation works for the New World First Bus (NWFB) depot was
completed. Concurrent superstructure construction activities at the NWFB depot
is not expected to give rise to a significant cumulative dust impact. There are no known major planned
construction activities in the vicinity of the site that may pose a potential
significant cumulative impact. Besides,
it is expected that even if there would be other construction activities
planned in future, these works will also be required to implement sufficient
dust control measures in accordance with the requirements of the Air
Pollution Control (Construction Dust) Regulation.
Dust Emission Modelling
4.5.5
Construction dust impact arising from the key dust emission
sources presented above during the foundation construction stage on the nearby
existing ASRs has been predicted using the air quality model “Fugitive Dust Model” (FDM). The model was particularly developed to
model fugitive dust emissions and is well accepted by HKEPD and USEPA for this
purpose. The model was developed based
on the widely used Gaussian plume formulae for estimation of pollutant
concentrations but has been adapted to incorporate a gradient-transfer
deposition algorithm which accounts for the settling out of dust particles, and
to include the wind dependent factor on dust emission rates. The model is designed to predict fugitive
dust dispersion from point, line, area and volume sources.
4.5.6
Based on information on general size distribution as reported
in Guide to Rock and Soil Descriptions
issued by the Geotechnical Control Office, Civil Engineering Services
Department, Hong Kong (1988), it has been assumed in the dust dispersion model
that 80% of particulates have size equal to 30µm, with the remaining 20%
assumed to be respirable with a size of 10µm.
An average dust density of 2,500 kg/m3 has been assumed in
the study.
à
Hourly
wind direction and speed, air temperature together with atmospheric Pasquill
stability class obtained at King’s Park;
à
Daily
morning and maximum mixing heights based on the radiosonde ascent at King’s
Park; and
à
Hourly
total sky cover, cloud amount and cloud based height of the 1st - 4th
layers observed at the Hong Kong Observatory Headquarters in Tsim Sha Tsui.
4.5.8
Given the stringent noise limits that need to be satisfied
before construction activities within the restricted hours will be allowed, it
is expected that there will only be construction activities during daytime from
0700 to 1900 hours. Nevertheless, to be
conservative in the study, dusty construction activities have been assumed to
be in operation continuously over a 24-hour period to give a worst-case
situation.
4.5.9
Maximum 1-hour and 24-hour TSP concentrations were predicted
at each representative assessment points A1 through A6 identified above. Given the limited height of the dust
emission sources, TSP concentrations were predicted at 1.5m, 5m and 10m above
ground at the representative assessment points to simulate the worst-case
situations. ASRs situated at higher
levels are expected to be subject to lower dust impact. With account of the background TSP levels,
the maximum 1-hour and 24-hour average TSP concentrations predicted were
compared with the 1-hour and 24-hour TSP limits of 500mg/m3 and 260mg/m3,
respectively. A typical FDM result file for construction dust impact assessment
is enclosed in Appendix 4-2 for reference.
Assessment Results (Unmitigated
Scenario)
4.5.10
The unmitigated maximum 1-hour and 24-hour average TSP
concentrations predicted at the representative assessment points, with
background concentration included, are presented in Table 4‑4 and Table
4‑5 below.
Table 4‑4 Maximum
1-hour TSP Concentrations predicted at the ASRs
(without
Mitigation Measures)
Ref. No.
|
Location
|
Predicted TSP concentrations
(mg/m3)
|
|
|
1.5m above ground
|
5m above ground
|
10m above ground
|
A1
|
Heng Fa Chuen
|
115
|
110
|
100
|
A2
|
Staff Quarters of the IVE
(Chai Wan)
|
190
|
157
|
136
|
A3
|
IVE (Chai Wan)
|
279
|
216
|
157
|
A4
|
IVE (Chai Wan)
|
504
|
378
|
212
|
A5
|
Tsui Hong House, Tsui Wan
Estate
|
180
|
173
|
151
|
A6
|
Tsui Sau House, Tsui Wan Estate
|
227
|
217
|
184
|
Note: Background TSP concentration of 79mg/m3 has been included.
Table
4‑5 24-hour
Average TSP Concentrations predicted at the ASRs
(without
Mitigation Measures)
Ref. No.
|
Location
|
Predicted TSP concentration
(mg/m3)
|
|
|
1.5m above ground
|
5m above Ground
|
10m above Ground
|
A1
|
Heng Fa Chuen
|
89
|
89
|
88
|
A2
|
Staff Quarters of the IVE
(Chai Wan)
|
112
|
108
|
100
|
A3
|
IVE (Chai Wan)
|
143
|
132
|
110
|
A4
|
IVE (Chai Wan)
|
352
|
247
|
147
|
A5
|
Tsui Hong House, Tsui Wan
Estate
|
110
|
106
|
97
|
A6
|
Tsui Sau House, Tsui Wan
Estate
|
150
|
144
|
126
|
Note: Background concentration of 79mg/m3 has been included.
4.5.11
The modelling results for the unmitigated scenario revealed
that the nearby Air Sensitive Receivers will be subject to dust level at
acceptable levels, except at A4. In
accordance with the requirements set out in the Air Pollution Control (Construction
Dust) Regulation, sufficient dust control/ mitigation measures shall be
implemented to ensure full protection of the nearby ASRs.
Control
Measures for mitigating Fugitive Dust Emissions
4.5.12
The following measures are specifically recommended for
implementation together with those presented in the Air Pollution Control
(Construction Dust) Regulation:
General Site Management
4.5.13
Appropriate working methods should be devised and arranged to
minimise dust emissions and to ensure any installed air pollution control
system and measures are operated and/or implemented in accordance with their
design merits. In the event of
malfunctioning of any control system or equipment, the relevant dusty
activities shall stop until the relevant control system or equipment are
restored to proper functioning.
4.5.14
Frequent mist spraying should be applied on dusty areas. The frequency of spraying required will
depend upon local meteorological conditions such as rainfall, temperature, wind
speed and humidity. The amount of mist
spraying should be just enough to dampen the material without over-watering,
which could result in unnecessary surface water runoff.
4.5.15
No free falling of construction debris shall be allowed at the
site.
Vehicles and Site Haul Road
4.5.16
Dust emission from unpaved roads comes predominantly from
travelling of vehicles. Areas within the site where there are regular vehicle
movements should have an approved hard surface. Speed controls at an upper limit of 10 to 15 kph should be
imposed and their movements should be confined to designed roadways within the
site. All dusty vehicle loads should
have side and tail boards and should be covered by tarpaulin extending at least
300 mm over the edges of the side and tail boards. Wheel-wash troughs and hoses should be provided at exit points of
the site.
Material Stockpiling and Handling
4.5.17
The amount of stockpiling should be minimised as far as
practicable. The surface of the stockpile should be kept wet by spraying with
water. Dust emission during loading of
fill material to dump trucks should be mitigated by spraying to sufficiently
damp the material prior to any loading or unloading operation. Dusty
construction debris should be covered or stored inside enclosed areas where
practicable to avoid dust generation.
4.5.18
Watering is an effective dust control measure commonly
employed in storage piles and handling operations and should be implemented
where appropriate. Other control measures such as enclosed or semi-enclosed
windboard should be used, where applicable, to minimise dust emission.
4.5.19
With the implementation of the
above-mentioned dust mitigation measures together with those
required in the Air Pollution Control (Construction Dust) Regulation, it is
expected that a minimum dust control efficiency of at least 50% is
achievable. Table 4-6 and 4-7 present
the mitigated dust levels predicted at the ASRs based on 50% dust control
efficiency. Implementation of dust
control measures in accordance with the requirements under the Air Pollution
Control (Construction Dust) Regulation will therefore ensure that unacceptable
dust impact will not be generated.
Table 4‑6 Maximum
1-hour TSP Concentrations predicted at the ASRs
(with
Mitigation Measures)
Ref. No.
|
Location
|
Predicted maximum 1-hr TSP concentrations (mg/m3)
|
|
|
1.5m above ground
|
5m above ground
|
10m above ground
|
A1
|
Heng Fa Chuen
|
97
|
94
|
89
|
A2
|
Staff Quarters of the IVE
(Chai Wan)
|
134
|
118
|
107
|
A3
|
IVE (Chai Wan)
|
179
|
147
|
118
|
A4
|
IVE (Chai Wan)
|
292
|
228
|
146
|
A5
|
Tsui Hong House, Tsui Wan
Estate
|
130
|
126
|
115
|
A6
|
Tsui Sau House, Tsui Wan
Estate
|
153
|
148
|
132
|
Note: Background TSP concentration of 79mg/m3 has been included.
Table 4‑7 24-hour
Average TSP Concentrations predicted at the ASRs
(with
Mitigation Measures)
Ref. No.
|
Location
|
Predicted 24-hour average TSP concentration (mg/m3)
|
|
|
1.5m above ground
|
5m above Ground
|
10m above Ground
|
A1
|
Heng Fa Chuen
|
84
|
84
|
83
|
A2
|
Staff Quarters of the IVE
(Chai Wan)
|
95
|
94
|
90
|
A3
|
IVE (Chai Wan)
|
111
|
105
|
95
|
A4
|
IVE (Chai Wan)
|
216
|
163
|
113
|
A5
|
Tsui Hong House, Tsui Wan
Estate
|
94
|
93
|
88
|
A6
|
Tsui Sau House, Tsui Wan
Estate
|
115
|
111
|
103
|
Note: Background concentration of 79mg/m3 has been included.
4.5.20
Contour maps presenting the predicted mitigated maximum 1-hour
and 24-hour average TSP concentrations at 1.5m above ground are given in Figure
4-2 and Figure 4-3. Background TSP level has been included in the results. The results show that the fugitive dust
impact arising from the construction works when dust mitigation measures
required under the Air Pollution Control (Construction Dust) Regulation are
implemented will be within the relevant dust assessment criteria. Implementation of the recommended
Environmental Monitoring and Audit Program (EM&A) will further ensure full
protection of the nearby ASRs. Details
of the EM&A Programme are presented in the Environmental Management Plan
(EMP).
4.6
Vehicular Emission Impact Assessment
4.6.1
During the operational phase of the bus depot, vehicular
emission from buses running within the depot and commuting to and from the
depot is the focus of the assessment.
Emissions of the key criteria pollutants associated with vehicular
traffic, including nitrogen dioxide (NO2), carbon monoxide (CO), and
respirable suspended particulate (RSP) have been studied.
4.6.2
Potential cumulative air quality impact from the concurrent
operation of the NWFB depot in the area, as well as traffic emissions from the
nearby road carriageways have been taken account of quantitatively in the
study. Traffics generated from the
future landuses within the Chai Wan East Industrial Area have been considered
in the traffic forecast provided by the Project Traffic Consultant – LLA
Consultancy Limited.
4.6.3
Air pollutants may also be generated from other depot
operations including engine testing, brake testing and painting. However, the emission quantity and
associated air pollution is expected to be insignificant.
Open
Road Vehicular Emission
Traffic Forecast
4.6.4
Similar to other future developments, operation of the
proposed bus depot will inevitably results in generation of some traffic flows
on the nearby road carriageways. This
section assesses the potential air quality impact associated with traffic
movement in the study area, taking into account the additional traffic flows
generated from the proposed bus depot.
Effects of other possible future developments in the study area have
also been taken into account through incorporation of traffic generation into
the traffic forecast.
4.6.5
Traffic forecast for the year 2018 during the early morning
(0530 to 0630) and mid-night (2300 to 0000) peak hour, when the highest traffic
flow contribution is expected to be generated from the proposed bus depot, has
been adopted in the study. Traffic
generation from other possible future developments in the area, including the
NWFB depot has been taken into consideration in the preparation of the traffic
forecast. The traffic forecast data
prepared by the Project Traffic Consultant has been endorsed by Transport
Department for use in the EIA study (see Appendix 5-6). In the preparation of the traffic forecast,
the Traffic Consultant has taken into account the data presented in the
approved EIA reported carried out for NWFB Permanent Depot in Chai Wan to
ensure that a consistent and conservative approach is being followed. Table 4-8
and Table
4‑9 present the 2018 Traffic Forecast during the early
morning and nighttime peak hours when the highest bus flows will be generated
from the bus depot. Alignment of the
road carriageways studied is presented in Appendix 4-3.
Table
4‑8 Year
2018 Traffic Forecast during the early Morning Peak Leaving
Label
|
Traffic Volume (veh/hr)
|
% of Passenger Car
|
% of HGV
|
% of Bus
|
A
|
332
|
21.5
|
56.6
|
22.0
|
B
|
171
|
47.1
|
50.0
|
2.9
|
C
|
160
|
25.8
|
74.2
|
0.0
|
D
|
306
|
39.3
|
38.5
|
22.2
|
E
|
565
|
54.5
|
45.5
|
0.0
|
F
|
835
|
57.0
|
43.0
|
0.0
|
G
|
249
|
14.0
|
58.7
|
27.3
|
H
|
3086
|
71.1
|
26.6
|
2.4
|
I
|
114
|
15.0
|
85.0
|
0.0
|
J
|
162
|
24.2
|
72.7
|
3.1
|
K
|
47
|
25.0
|
28.2
|
46.8
|
L
|
212
|
24.3
|
75.7
|
0.0
|
M
|
232
|
24.3
|
75.7
|
0.0
|
N
|
3086
|
71.1
|
26.6
|
2.4
|
O
|
284
|
37.7
|
62.3
|
0.0
|
P
|
2694
|
70.1
|
29.9
|
0.0
|
Q
|
20
|
90.0
|
10.0
|
0.0
|
R
|
20
|
90.0
|
10.0
|
0.0
|
Table
4‑9 Year
2018 Traffic Forecast during the Nighttime Peak Return
Label
|
Traffic Volume (veh/hr)
|
% of Passenger Car
|
% of HGV
|
% of Bus
|
A
|
734
|
40.9
|
42.7
|
16.3
|
B
|
346
|
40.7
|
42.0
|
17.3
|
C
|
50
|
93.8
|
6.2
|
0.0
|
D
|
368
|
57.8
|
25.9
|
16.3
|
E
|
889
|
86.3
|
13.7
|
0.0
|
F
|
1325
|
77.6
|
22.4
|
0.0
|
G
|
368
|
44.9
|
38.8
|
16.3
|
H
|
2564
|
58.8
|
36.5
|
4.7
|
I
|
68
|
18.0
|
82.0
|
0.0
|
J
|
647
|
25.4
|
65.3
|
9.3
|
K
|
85
|
38.6
|
14.3
|
47.1
|
L
|
477
|
44.6
|
55.4
|
0.0
|
M
|
481
|
44.6
|
55.4
|
0.0
|
N
|
2564
|
58.8
|
36.5
|
4.7
|
O
|
433
|
55.8
|
44.2
|
0.0
|
P
|
1654
|
59.8
|
40.2
|
0.0
|
Q
|
20
|
90.0
|
10.0
|
0.0
|
R
|
20
|
90.0
|
10.0
|
0.0
|
Air Quality Modelling
4.6.6
Potential vehicular emission from open road traffic has been
assessed with the air quality model CALINE4.
The model is a line source model developed by the California Department
of Transport. It was developed based on
the Gaussian diffusion formulae and a mixing zone concept in predicting
dispersion of pollutants emitted from road carriageways.
4.6.7
As the bus depot will commence operation in 2003, to be
conservative in the assessment, emission factors for vehicular pollutants
recommended by DEP in air quality study have been used with 2018 traffic
forecast data in the modeling study. As
pollutant emission factors are expected to be reduced as technology advance in
reducing vehicular emissions, this approach to the study is considered very
conservative. Table 4-10 presents the
2003 vehicular emission factors of CO, NOx and RSP for passenger
cars, buses and heavy diesel vehicles.
Table 4‑10 2003
Vehicular Emission Factors
Vehicle Type
|
Emission Factor (mg/km)
|
|
CO
|
NOx
|
RSP
|
Passenger Car
(Petrol)
|
2.34
|
0.90
|
0.03
|
Franchised
Bus Double Deck (FBDD)
|
9.22
|
10.53
|
1.17
|
Heavy Diesel Vehicle
|
8.53
|
6.21
|
1.05
|
The following assumptions
were adopted throughout the study :
i.
NOx
is a mixture of NO and NO2;
ii.
20%
of NOx is assumed to be NO2;
iii.
NO
was modelled as “Inert Gas”; with a molecular weight of 46g;
iv.
The
proportion of RSP in the vehicular emission is assumed to be 100% of the
particulate matter which is, in general, less than 10 mm
in the aerodynamic diameter.
4.6.8
Pasquill Stability Class F with a wind speed of 1m/s has been
adopted in the CALINE4 modelling to simulate the worst-case meteorological
conditions. The ambient temperature was
assumed to be 25 degree Celsius. The
average mixing height was taken as 500m according to monitoring data obtained
from Kai Tak Weather Station. Wind
direction standard deviation of 6 degree.
The aerodynamic roughness coefficient was set at 100cm.
4.6.9
Concentrations of maximum 1-hour CO, NO2 and RSP at
the representative assessment points A1 through A6 presented in Figure 4-1 were
predicted from the model. As there is
currently no hourly AQO for RSP, the modeled peak hour RSP concentrations were
converted to daily average concentration for checking compliance with the daily
criteria of 180mg/m3. 24-hour NO2 concentrations at the
assessment points were also predicted using the same approach. Assuming that the predicted maximum peak
hour traffic flow would last for 10 hours and the wind would be blowing at the
worst direction for 24 hours, a conversion factor of 0.4 has been applied to
convert maximum 1-hour RSP and NO2 concentrations to maximum 24-hour
average for comparison with the relevant Air Quality Objectives.
Assessment Results
4.6.10
Table 4-11 presents the modeled maximum 1-hour NO2,
1-hour CO and 24-hour average RSP and NO2 concentrations at the
representative assessment points for open road vehicular emission. Background pollutant concentrations have
been added to the results. Typical CALINE4 result files are presented in Appendix
4-4.
4.6.11
It can be noted that all modeling results are falling well
within the relevant AQOs.
Table
4‑11 Predicted
Pollutant Concentrations from Open Road Vehicular Emission
Ref.
No.
|
Location
|
Predicted pollutant concentrations (mg/m3) at discrete receptor
|
|
|
|
Height
above ground (m)
|
1-hr NO2
|
24-hr NO2
|
1-hr CO
|
24-hr RSP
|
|
|
|
1.5
|
5
|
10
|
15
|
20
|
1.5
|
5
|
10
|
15
|
20
|
1.5
|
5
|
10
|
15
|
20
|
1.5
|
5
|
10
|
15
|
20
|
|
A1
|
Heng Fa
Chuen
|
104
|
104
|
104
|
104
|
104
|
81
|
81
|
81
|
81
|
81
|
1635
|
1520
|
1520
|
1406
|
1406
|
63
|
62
|
59
|
56
|
55
|
|
A2
|
Staff
Quarters of the IVE (Chai Wan)
|
179
|
141
|
141
|
141
|
141
|
111
|
96
|
96
|
96
|
96
|
1864
|
1864
|
1864
|
1749
|
1749
|
74
|
73
|
71
|
69
|
66
|
|
A3
|
IVE
(Chai Wan)
|
179
|
179
|
179
|
141
|
141
|
111
|
111
|
111
|
96
|
96
|
1978
|
1978
|
1864
|
1864
|
1749
|
77
|
76
|
74
|
71
|
68
|
|
A4
|
IVE
(Chai Wan)
|
141
|
141
|
141
|
141
|
141
|
96
|
96
|
96
|
96
|
96
|
1864
|
1864
|
1749
|
1749
|
1635
|
71
|
70
|
68
|
66
|
64
|
|
A5
|
Tsui
Hong House, Tsui Wan Estate
|
141
|
141
|
141
|
104
|
104
|
96
|
96
|
96
|
81
|
81
|
1749
|
1749
|
1635
|
1520
|
1520
|
69
|
67
|
64
|
62
|
60
|
|
A6
|
Tsui
Sau House, Tsui Wan Estate
|
141
|
141
|
141
|
104
|
104
|
96
|
96
|
96
|
81
|
81
|
1864
|
1749
|
1635
|
1635
|
1520
|
70
|
68
|
64
|
62
|
60
|
|
|
Air Quality Objectives (AQO)
|
300
|
|
30,000
|
180
|
|
Note:
Background pollutant concentrations are included in the results.
Depot Emissions
4.6.12
In addition to the off-site bus traffic, operation of the bus
depot would also result in generation of some air pollutants directly from the
depot.
Pollutant
Emission Rates
4.6.13
Exhaust emission from buses moving and idling inside the
proposed bus depot building was studied.
As discussed before, maximum bus flows leaving or returning to the bus
depot are expected to occur during early morning (0530 to 0630) and at
mid-night (2300 to 0000). Bus flow
information, in terms of worst-case number of buses entering and leaving each
floor of the proposed depot building during the peak hours, was estimated by
the project traffic consultant and are summarised in Table 4‑12.
Table
4‑12 Worst-case
Bus Flow entering/ leaving the Depot Building
|
Number of Buses/Hour1
|
|
During mid-night
|
During Early Morning
|
Floor Level
|
Entering
|
Leaving
|
Entering
|
Leaving
|
G/F
|
80
|
80
|
5
|
90
|
1/F2
|
80
|
80
|
0
|
85
|
Roof floor3
|
70
|
70
|
0
|
85
|
Notes:
1.
Bus flow data for each floor includes the accumulated flow passing each
floor level;
2.
1/F maintenance bay is for annual maintenance activities which occur
outside the above peak hours. Nevertheless, to be conservative, the maximum
hourly bus flows which are expected to occur during daytime have been assumed
for the mid-night scenario;
3.
Maximum numbers of buses are expected to return to the depot for parking
at approximately 19:30 to 20:30. Again,
as a conservative approach, the peak hourly flows have also been assumed to
occur during the mid-night scenario for the vehicular emission impact study.
4.6.14
Vehicular emission within the bus depot would be generated
from bus movement within the depot, as well as from bus idling. Emission factors for these two activities
were referenced to the Fleet Average Emission Factors calculated by the “FAEF”
Model, and EPD recommended idling factors.
These are summarised in Table
4‑13.
Table
4‑13 Emission
Factor for Buses inside Depot
|
Emission Factors
|
Bus activity
|
NOx
|
CO
|
RSP
|
Traveling (g/km)
|
11.71
|
8.89
|
1.38
|
Idling (g/min/vehicle)
|
2.0
|
2.0
|
0.042
|
4.6.15
Worst-case average emission rates of NO2, CO and
RSP from bus movement and idling within the bus depot were calculated from the
estimated maximum hourly bus flows and bus traveling distance and are
summarised in Table
4‑14. A
spreadsheet showing the calculation of these emission rates are set out in
Appendix 4-5. These highest pollutant
emission rates will only occur during the peak hour. Applying these emission rates in the model for testing of
pollutant dispersion under different worst-case meteorological conditions at
different hours of the days will therefore generate conservative results. Taking into account the worst-case maximum
number of buses, multiple point sources were assumed to be present concurrently
as a conservative approach in the air quality modelling.
Table
4‑14 Bus
Depot Air Pollutant Emission Rates
|
|
Pollutant
Emission Rate (g/s) Per Source
|
Floor
|
No. of
Sources
|
NO2
|
CO
|
RSP
|
G/F
|
80
|
0.00130
|
0.00032
|
0.000164
|
1/F
|
80
|
0.00062
|
0.00015
|
0.000059
|
Roof floor
|
70
|
0.00069
|
0.00016
|
0.000069
|
4.6.16
In addition to the proposed Bus Depot, New World First Bus
(NWFB) Services Limited will also operate a similar bus depot facility located
at about 135m to the north of the development site. Similar pollutant emission rates estimated from bus movement and
idling within the NWFB depot were identified from the NWFB EIA report (EIAO
registration no.: EIA-034/1999) and inputted to the ISCST3 for studying the
potential cumulative air quality impact due to emissions from the two depots.
Air Quality Modelling
4.6.17
The dispersion of air pollutants released from the proposed
bus depot and NWFB depot was studied quantitatively using the air quality model
“Industrial Source Complex Short Term Version 3 (ISCST3)” released by Trinity
Consultants Incorporated. This model was developed based on the principle of
Gaussian dispersion and is widely acceptable by authorities worldwide including
the United States Environmental Protection Agency (USEPA) and the Hong Kong
Environmental Protection Department (EPD).
Pollutant emissions from each floor of the bus depot were modeled. The
emission heights were taken at 0.5m above the floor slabs, which is the
approximate height of the bus exhaust pipes.
4.6.18
The same set of meteorological data as presented in Section 4.5.7 has been adopted in the air quality modeling. Background pollutant concentrations as
presented in Table
4‑3 were adopted.
Modelling Results
4.6.19
Table 4-15 presents the predicted maximum 1-hour NO2,
CO and 24-hour average RSP and NO2 concentrations at the
representative assessment points A1 through A6 due to emission from the two
depots. Typical ISCST3 result files can
be found in Appendix 4-6. All modeling
results are found to be well within the AQOs.
Cumulative
Impact from Open Road Traffic and Depot Emissions
4.6.20
Cumulative pollutant concentrations at the representative
assessment points due to operations of the two bus depots, off-site road
vehicular emissions and background pollutant concentrations were conservatively
estimated from summation of the ISCST3 and CALINE4 results and are presented in
Table 4-16.
Table 4‑15 Predicted
pollutant concentrations due to emissions from Citybus Depot and NWFB Depot
Ref. No.
|
Location
|
Predicted pollutant concentrations (mg/m3)
at discrete receptor
|
|
|
|
Height
above ground (m)
|
1-hr NO2
|
24-hr NO2
|
1-hr CO
|
24-hr RSP
|
|
|
|
1.5
|
5
|
10
|
15
|
20
|
1.5
|
5
|
10
|
15
|
20
|
1.5
|
5
|
10
|
15
|
20
|
1.5
|
5
|
10
|
15
|
20
|
|
A1
|
Heng Fa
Chuen
|
74
|
74
|
74
|
73
|
74
|
68
|
68
|
68
|
68
|
68
|
1211
|
1210
|
1209
|
1208
|
1210
|
48
|
48
|
48
|
49
|
48
|
|
A2
|
Staff
Quarters of the IVE (Chai Wan)
|
82
|
82
|
81
|
80
|
79
|
70
|
70
|
70
|
70
|
70
|
1242
|
1242
|
1240
|
1236
|
1230
|
49
|
49
|
49
|
51
|
49
|
|
A3
|
IVE (Chai
Wan)
|
82
|
82
|
83
|
82
|
80
|
71
|
71
|
71
|
71
|
71
|
1242
|
1243
|
1245
|
1243
|
1236
|
49
|
49
|
49
|
52
|
49
|
|
A4
|
IVE (Chai
Wan)
|
81
|
81
|
83
|
83
|
81
|
75
|
75
|
75
|
75
|
75
|
1237
|
1240
|
1245
|
1245
|
1240
|
51
|
51
|
51
|
56
|
51
|
|
A5
|
Tsui Hong
House, Tsui Wan Estate
|
85
|
85
|
85
|
84
|
83
|
72
|
72
|
72
|
72
|
72
|
1258
|
1258
|
1256
|
1252
|
1247
|
50
|
50
|
50
|
53
|
50
|
|
A6
|
Tsui Sau
House, Tsui Wan Estate
|
83
|
83
|
82
|
82
|
80
|
71
|
71
|
71
|
71
|
71
|
1247
|
1247
|
1245
|
1242
|
1236
|
49
|
49
|
49
|
52
|
49
|
|
|
Air Quality
Objectives (AQO)
|
300
|
|
30,000
|
180
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Note: Background
pollutant concentrations are included.
Table 4‑16 Cumulative
Pollutant Concentrations from Open Road Traffic Emission & Depots Emission
Ref. No.
|
Location
|
Predicted pollutant
concentrations (mg/m3) at discrete receptor
|
|
|
|
Height above ground (m)
|
1-hr NO2
|
24-Hr NO2
|
1-hr CO
|
24-hr RSP
|
|
|
|
1.5
|
5
|
10
|
15
|
20
|
1.5
|
5
|
10
|
15
|
20
|
1.5
|
5
|
10
|
15
|
20
|
1.5
|
5
|
10
|
15
|
20
|
|
A1
|
Heng Fa Chuen
|
112
|
112
|
111
|
111
|
111
|
83
|
83
|
84
|
84
|
84
|
1668
|
1554
|
1553
|
1437
|
1439
|
64
|
63
|
60
|
59
|
56
|
|
A2
|
Staff Quarters of the IVE (Chai Wan)
|
195
|
157
|
157
|
156
|
154
|
115
|
100
|
100
|
100
|
100
|
1929
|
1929
|
1927
|
1809
|
1803
|
76
|
75
|
73
|
73
|
68
|
|
A3
|
IVE (Chai Wan)
|
195
|
195
|
195
|
157
|
156
|
116
|
116
|
116
|
101
|
101
|
2043
|
2044
|
1931
|
1930
|
1809
|
79
|
78
|
76
|
76
|
71
|
|
A4
|
IVE (Chai Wan)
|
156
|
157
|
158
|
158
|
157
|
105
|
105
|
105
|
105
|
105
|
1924
|
1927
|
1818
|
1817
|
1698
|
75
|
75
|
73
|
75
|
68
|
|
A5
|
Tsui Hong House, Tsui Wan Estate
|
161
|
161
|
160
|
122
|
120
|
102
|
102
|
102
|
87
|
87
|
1830
|
1830
|
1713
|
1595
|
1590
|
72
|
70
|
67
|
68
|
62
|
|
A6
|
Tsui Sau House, Tsui Wan Estate
|
158
|
158
|
158
|
119
|
118
|
101
|
101
|
101
|
86
|
86
|
1934
|
1819
|
1703
|
1699
|
1580
|
72
|
70
|
67
|
68
|
63
|
|
|
Air Quality Objectives (AQO)
|
300
|
|
30,000
|
180
|
|
Note: Background pollutant concentrations are
included.
4.6.21
The maximum 1-hour NO2 concentration was predicted
at A3 at 10m above ground from the modelling. In addition to the discrete
representative assessment points, assessment points were selected based on a
50m x 50m grid covering the key air sensitive areas of interest, viz. Heng Fa
Chuen, IVE (Chai Wan) and its associated Staff Quarters, and Tsui Wan Estate. Pollutant isopleths of maximum 1-hour NO2,
1-hour CO and 24-hour RSP and NO2 were generated from the ISCST3 and
CALINE4 modelling results obtained at the worst affected level at 10m above
ground. Background pollutant
concentrations set out in Table
4‑3 were added to the modelling results for comparison
with the relevant AQOs. The contour
maps are presented in Figure 4-4 to Figure 4-7.
4.6.22
All predicted air pollutant concentrations at various levels
of the ASRs are well within the AQOs.
The assessment results reveal that vehicular emissions from open road
traffic and emission from the two bus depots will unlikely pose an unacceptable
air quality impact on the surrounding ASRs.
4.7
Environmental Monitoring & Audit (EM&A) Requirements
4.7.1
The quantitative construction dust impact assessment confirms
that no unacceptable air quality impact affecting the nearby ASRs is
anticipated when the required dust control/ mitigation measures required under
the Air Pollution Control (Construction Dust) Regulation are implemented. Nevertheless, for checking the
implementation of the dust mitigation measures required under the Air Pollution
Control (Construction Dust) Regulation, implementation of a dust monitoring
programme is recommended as part of the environmental monitoring and audit
(EM&A) programme.
4.7.2
The detailed vehicular emission impact assessment indicates
that vehicular emission from buses will not be a concern during the operational
phase. The carrying out of air quality
EM&A works in relation to air quality during the operational phase is not
considered necessary.
4.8
Assessment Conclusions
Construction Phase
4.8.1
The dust impact assessment concluded that the dust impact
during the construction phase of the development will be in compliance with the
air quality criteria when dust control measures required under the Air
Pollution Control (Construction Dust) Regulation are in place. Construction air quality impact should be
minor and effective dust control can be achieved by implementation of the dust
control measures required under the Air Pollution Control (Construction
Dust) Regulation.
Operational Phase
4.8.2
Potential air quality impact arising from the operation of the
proposed bus depot, including emission directly from the bus depot and from
open road vehicular emission, has been assessed. Direct emission from the NWFB depot, as well as vehicular
emission from traffic generated by the planned landuses including the NWFB
depot in the area, has been considered.
The cumulative pollutant concentrations predicted are all satisfying the
relevant AQOs. The assessment results
obtained with a conservative assessment approach indicate that the operation of
the bus depot will not cause any unacceptable air quality impact on the
surrounding air sensitive receivers.
5.
Noise Impact Assessment
5.1
Introduction
5.1.1 This
section presents an assessment of noise impact associated with the construction
and operation of the project. During
the construction phase, potential noise impact arising from the operation of
powered mechanical equipment (PME) at the work sites is the key interest. Potential traffic noise impact from buses
running on the road carriageways in the vicinity of the bus depot and that
generated from fixed noise sources are the focus of the operational phase
impact study. Where necessary,
mitigation measures will be recommended to reduce the noise impact down to meet
acceptable levels.
5.2
Study Area and Noise
Sensitive Receivers (NSRs)
5.2.1 A
study area of 300m from the boundary of the project site has been adopted in
the study in accordance with the requirement stated in the EIA Study Brief.
5.2.2 As
defined in Annex 13 of the EIAO-TM, domestic premises and schools are defined
as noise sensitive receivers. In the
current study, the nearest NSRs identified in the proximity of the proposed Bus
depot are the residential developments to the north and south of the Bus Depot,
namely Heng Fa Chuen and Tsui Wan Estate respectively, and the IVE (Chai Wan)
and its associated Staff Quarters.
Representative assessment points (RAPs) have been selected for each of
these NSRs and their locations are shown in Figure 4-1. These RAPs are described in Table 5‑1. The
separation distance between the RAPs and the bus depot is also shown in Table
5-1.
Table 5‑1
Representative Assessment Points selected for Noise Impact Assessment
RAPs
|
Description
|
Floors
|
Separation (Approx.) (m)
|
HF-1
|
Block 50, Heng Fa Chuen
|
G/F to 20/F
|
390
|
HF-2
|
Block 16, Heng Fa Chuen
|
G/F to 20/F
|
658
|
SH-1
|
Staff Quarters of the IVE (Chai Wan)
|
G/F to 25/F
|
200
|
SH-2
|
Staff Quarters of the IVE (Chai Wan)
|
G/F to 25/F
|
160
|
IV-1
|
IVE (Chai Wan)
|
G/F to 5/F
|
175
|
IV-2
|
IVE (Chai Wan)
|
G/F to 5/F
|
85
|
TW-1
|
Tsui Sau House, Tsui Wan Estate
|
G/F to 30/F
|
165
|
TW-2
|
Tsui Fuk House, Tsui Wan Estate
|
G/F to 30/F
|
235
|
TW-3
|
Tsui Ling House, Tsui Wan Estate
|
G/F to 30/F
|
305
|
TW-4
|
Tsui Hong House, Tsui Wan Estate
|
G/F to 30/F
|
205
|
5.2.3 Eastern
facade of IVE (Chai Wan) Staff Quarters (SH-3 and SH-4 in Figure 4-1) is installed
with fixed windows (i.e. does not rely on opened windows for ventilation) such
that the relevant noise standards are not applicable. Therefore, RAPs were only selected on the western façade of the
Staff Quarters for the assessment. Besides, it is identified that IVE (Chai
Wan) is installed with air-conditioners such that the occupants in the teaching
classrooms and laboratories will not rely on openable windows as the primary
means for ventilation.
5.2.4 No
planned NSRs are identified in the proximity of the bus depot that could be
subject to a noise impact resulting from the project.
5.2.5 The
existing dominant noise sources identified in the vicinity of these NSRs
include traffic noise from the nearby major road carriageways (e.g. Island
Eastern Corridor) and railway noise from the MTR tracks.
5.3
Construction Noise Impact Assessment
Legislation and Assessment Criteria
5.3.1 Construction
noise is controlled under the Noise
Control Ordinance (NCO) which prohibits the use of powered mechanical
equipment (PME) during the restricted hours (7 p.m. to 7 a.m. on normal
weekdays and any time on a public holiday, including Sunday) without a valid
Construction Noise Permit (CNP) granted by the Authority. The criteria and procedures for issuing such
a permit are specified in the “Technical Memorandum on Noise From Construction
Works Other than Percussive Piling” (TM1).
5.3.2 For
construction works other than percussive piling, although TM1 do not provide
control over daytime construction activities, noise limits are set out in Table
1B of Annex 5 of the EIAO TM which have been adopted as the assessment criteria
in this study. These noise standards
are summarised in Table
5‑2 below:
Table 5‑2 Noise Limits for
Daytime Construction Activities
NSR
|
0700 to 1900
hours on any day not being a Sunday or general holiday Leq (30min.)
dB (A)
|
All domestic
premises including temporary housing accommodation
|
75
|
Educational
institutions including kindergartens, nurseries.
|
70
65 (during examination)
|
N.B. (i) The above standards apply to uses which
rely on opened windows for ventilation;
(ii) The above
standards shall be viewed as the maximum permissible noise levels assessed at
1m from the external facade.
5.3.3 Construction
works during the restricted hours are not required. However, if the Contractor finds that works during restricted
hours are required, then, he should apply for a Construction Noise Permit
(CNP). Despite any description or
assessment made in this EIA Report on construction noise aspects, there is no
guarantee that a CNP will be issued for the project construction. The Noise Control Authority will consider a
well-justified CNP application, once filed, for construction works within
restricted hours as guided by the relevant Technical Memoranda issued under the
Noise Control Ordinance. The Noise
Control Authority will take into account of contemporary conditions/ situations
of adjoining land uses and ay previous complaints against construction
activities at the site before making his decision in granting a CNP. Nothing in this EIA Report shall bind the
Noise Control Authority in making his decision. If a CNP is to be issued, the Noise Control Authority shall
include in it any condition he thinks fit.
Failure to comply with any such conditions will lead to cancellation of
the CNP and prosecution action under the NCO.
5.3.4 With
effect from 1 November 96, the use of specified powered mechanical equipment
(SPME) for carrying out construction work other than percussive piling and/ or
the carrying out of prescribed construction work (PCW) within a designated area
are also brought under control. The relevant technical details are provided in
the “Technical Memorandum on Noise from Construction Work in Designated Areas”
(TM2).
5.3.5 Percussive
piling is controlled similarly by a noise permit system and described in the
NCO and the “Technical Memorandum On Noise From Percussive Piling” (TM3) which
restrict the number of hours during which piling can be conducted. No percussive piling may be carried out in
the territory without a valid CNP issued by the Authority. Besides, a CNP will only be granted for
percussive piling which is scheduled during normal working hours between 7 a.m.
to 7 p.m. from Monday to Saturday. The
carrying out percussive piling is prohibited at any time on Sundays and public
holidays as well as during the weekday from 7 p.m. to 7 a.m. the next day.
Assessment Methodology
5.3.6 The
approach used in the assessment of noise from construction works other than percussive
piling is based on standard acoustic principles, and the guidelines given Para.
5.3 and 5.4 of Annex 13 of the EIAO TM.
The methodology adopted is the same as that presented in TM1.
5.3.7 The
methodology for assessing construction noise impact arising from the project
has been developed based on the standard acoustic principles in TM1. In brief,
this includes the following steps:
(i)
based
on the preliminary construction programme given in Figure 3-9, identify the most likely powered
mechanical equipment (PME) to be used during foundation construction and
superstructure construction;
(ii)
identify
the nearest representative assessment points of the NSRs to the work sites;
(iii)
calculate
the total Sound Power Level (SWL) of the equipment that would likely be used
simultaneously at the notional source location of the site;
(iv)
calculate
the Predicted Noise Level (PNL) based on distance attenuation from the notional
source positions to the NSRs;
(v)
with
consideration of the effect of façade reflection at the NSRs, calculate the
Corrected Noise Level (CNL) at the NSRs; and
(vi)
compare
the CNL with the relevant daytime noise limits and identify situations and
locations where the implementation of construction noise mitigation measures
would be necessary.
Noise Sources
5.3.8 Exact
details on the PME to be used during the construction phase would not be
available before the appointment of the Contractor in future. Nevertheless, based on previous experience
in similar construction projects, the Project Engineer, Wong Pak Lam &
Associates Limited, has developed a preliminary PME inventory for the purpose
of quantitative assessments in the study.
Table 5-3 through Table 5-5 present the PME inventories for the
foundation construction works; sheet piling and pile cap construction, and
superstructure construction, respectively.
The plant inventories listed in these tables have been confirmed by the
Project Architect based on his experience in similar projects to be practical
and practicable for completing the works within the planed construction programme,
and demonstrated in practices through similar projects undertaken by
contractors. Potential cumulative noise
impact from concurrent use of different groups of PMEs has been assessed in the
study for identification of the mitigation measures required under these
situations.
5.3.9 The
carrying out of a quantitative construction noise assessment based on the
preliminary PME inventories established at this planning stage will allow the
identification of potential construction noise problem and location of the
potentially affected NSRs such that practicable and sufficient noise mitigation
measures can be derived accordingly at this early stage and incorporated as
contract requirements for the future Contractor to follow. Implementation of sufficient noise
mitigation can be checked through Environmental Monitoring and Audit
requirements.
Table 5‑3 PME Inventory for Foundation Construction Works
PME
|
No.
of Equipment
|
SWL,
dB(A)
|
Piling, large diameter bored, oscillator
|
10
|
115
|
Piling, large diameter bored, reverse
circulation drill
|
7
|
100
|
Generator
|
4
|
108
|
Excavator
|
4
|
112
|
Lorry
|
2
|
112
|
Crawler crane
|
13
|
112
|
Concrete lorry mixer
|
4
|
109
|
Dump
Truck
|
3
|
117
|
Table 5‑4 Inventory of PMEs during
Sheet Piling and Pile Cap Construction
Equipment
Group
|
PME
|
No. of Equipment
|
SWL, dB(A)
|
1
|
Compressor
<10m3 /min
|
2
|
100
|
|
Concrete
pump
|
1
|
109
|
|
Gen |