This Section
identifies the potential wastes arising from the construction of the Project
and potential environmental impacts associated with the handling and disposal
of waste. The assessment is
conducted in accordance with the criteria in Annexes 7 and 15 of the EIAO-TM and the requirements of the EIA Study Brief for the Project, which
are summarised as follows:
·
Analysis
of Activities and Waste Generation – identify the quantity, quality and timing
of the waste arising as a result of the construction and operation activities
of the Project;
·
Proposal
for Waste Management – evaluate the opportunities for reducing waste
generation, on-site / off-site reuse and recycling; estimate the types and
quantities of waste required to be disposed and the disposal options; the
impact caused by handling, collection and disposal of waste;
·
Land
Contamination Potential – identify all land lots/sites within the study area
boundary which are potential contaminated and provides list of potential
contaminants and possible remediation options.
7.2
Relevant
Legislation and Guidelines
The following legislation covers, or has
some bearing upon, the handling, treatment and disposal of wastes in
·
Waste Disposal Ordinance (Cap 354);
·
Waste Disposal (Chemical Waste) (General)
Regulation (Cap 354C);
·
Land (Miscellaneous Provisions) Ordinance
(Cap 28); and
·
Public Health and Municipal Services
Ordinance (Cap 132) - Public Cleansing and Prevention of Nuisances Regulation.
7.2.1
Waste Disposal Ordinance (Cap 354)
The Waste
Disposal Ordinance (WDO) prohibits the unauthorised disposal of wastes,
with waste defined as any substance or article, which is abandoned. Under the WDO, wastes can only be disposed of at a licensed site. A breach of these regulations can lead
to the imposition of a fine and/or a prison sentence. The WDO
also provides for the issuing of licences for the collection and transport
of wastes. Licences are not,
however, currently issued for the collection and transport of construction
waste or trade waste.
The Waste Disposal (Charges for Disposal of
Construction Waste) Regulation defined construction waste as any substance,
matters or things that is generated from construction work and abandoned,
whether or not it has been processed or stockpiled before being abandoned, but
does not include any sludge, screening or matter removed in or generated from
any desludging, desilting or dredging works.
The Construction
Waste Disposal Charging Scheme came into operation on 1 December 2005. Processing of account applications by
the EPD started on the same day. A
contractor who undertakes construction work with value of HK$1 million or above
is required to open a billing account solely for the contract. Charging for the disposal of construction
waste started on 20 January 2006.
Depending on the percentage of inert materials, construction & demolition
materials (C&D materials) can be disposed of at public fill, sorting
facilities, landfills and outlying islands transfer facilities, where differing
disposal costs would be applied.
The scheme encourages waste reduction so that the contractor or Project
Proponent can minimise their costs.
Table 7.2a summarises the
Government’s C&D materials disposal facilities, the types of waste accepted
and disposal the associated costs.
Table 7.2a Government
Waste Disposal Facilities for C&D Materials
|
Government Waste Disposal Facilities |
Type of Construction Waste Accepted |
Charge Per Tonne |
|
Public
fill reception facilities |
Consisting
entirely of inert construction waste |
$27 |
|
Sorting
facilities |
Containing
more than 50% by weight of inert construction waste |
$100 |
|
Landfills
|
Containing
not more than 50% by weight of inert construction waste |
$125 |
|
Outlying |
Containing
any percentage of inert construction waste |
$125 |
7.2.2
Waste Disposal (Chemical Waste) (General)
Regulation
Chemical waste as defined under the Waste Disposal (Chemical Waste) (General)
Regulation includes any substance being scrap material, or unwanted
substances specified under Schedule 1
of the Regulation, if such a
substance or chemical occurs in such a form, quantity or concentration so as to
cause pollution or constitute a danger to health or risk of pollution to the
environment.
Chemical waste
producers shall register with the Environmental Protection Department
(EPD). Any person who contravenes
this requirement commits an offence and is liable to a fine and imprisonment. Producers of chemical wastes must treat
their wastes, utilising on-site plant licensed by the EPD or have a licensed
collector take the wastes to a licensed facility. For each consignment of wastes, the
waste producer, collector and disposer of the wastes must sign all relevant
parts of a computerised trip ticket.
The system is designed to allow the transfer of wastes to be traced from
cradle-to-grave.
The Regulation
prescribes the storage facilities to be provided on site including labelling
and warning signs. To minimise the
risks of pollution and danger to human health or life, the waste producer is
required to prepare and make available written procedures to be observed in the
case of emergencies due to spillage, leakage or accidents arising from the
storage of chemical wastes. He/she
must also provide employees with training in such procedures.
7.2.3
Land (Miscellaneous Provisions) Ordinance
(Cap 28)
The inert portion of C&D materials
(also called public fill) may be taken to public filling areas. Public filling areas usually form part
of land reclamation schemes and are operated by the Civil Engineering and
Development Department (CEDD). The Land (Miscellaneous Provisions) Ordinance requires
that individuals or companies who deliver public fill to the public filling
areas obtain Dumping Licences. The
licences are issued by the CEDD under delegated authority from the Director of
Lands.
Individual licences and windscreen
stickers are issued for each vehicle involved. Under the licence conditions, public
filling areas will accept only inert building debris, soil, rock and broken
concrete. There is no size limit on
rock and broken concrete, and a small amount of timber mixed with inert
material is permissible. The
material should, however, be free from marine mud, household refuse, plastic,
metal, industrial and chemical wastes, animal and vegetable matter and any
other materials considered unsuitable by the public filling supervisor.
7.2.4
Public Cleansing and Prevention of
Nuisances Regulation
This Regulation provides further control on
the illegal dumping of wastes on unauthorised (unlicensed) sites. The illegal dumping of wastes can lead
to a fine and/or imprisonment.
7.2.5
Other Relevant Guidelines
Other ’guideline’
documents, which detail how the project proponent or contractor should comply
with the local regulations, are as follows:
·
Waste Disposal Plan for Hong Kong (December 1989), Planning, Environment
and Lands Branch Government Secretariat,
·
Environmental Guidelines for Planning In
Hong Kong (1990), Hong
Kong Planning Standards and Guidelines, Hong Kong Government;
·
New Disposal Arrangements for Construction
Waste (1992), EPD &
CED,
·
Code of Practice on the Packaging,
Labelling and Storage of Chemical Wastes (1992), EPD,
·
Works Branch Technical Circular (WBTC) No.
32/92, The Use of Tropical Hard Wood on Construction Site; Works Branch,
·
WBTC No. 2/93, Public Dumps, Works Branch,
·
WBTC No. 2/93B, Public Filling Facilities, Works Branch,
·
Waste Reduction Framework Plan, 1998 to
2007, Planning,
Environment and Lands Bureau, Government Secretariat, 5 November 1998;
·
WBTC Nos. 25/99, 25/99A and
25/99C, Incorporation of Information on Construction and Demolition Material
Management in Public Works Sub-committee Papers; Works Bureau,
·
WBTC No. 12/2000, Fill Management; Works Bureau,
·
WBTC Nos. 6/2002 and 6/2002A, Enhanced
Specification for Site Cleanliness and Tidiness. Works Bureau,
·
WBTC No. 12/2002, Specification
Facilitating the Use of Recycled Aggregates. Works Bureau,
·
ETWBTC No. 33/2002, Management of
Construction and Demolition Material Including Rock; Environment,
Transport and Works Bureau,
·
ETWBTC No. 31/2004, Trip Ticket System for
Disposal of Construction & Demolition Materials, Environment, Transport and Works Bureau, Hong Kong
SAR Government; and
·
ETWBTC No. 19/2005, Environmental
Management on Construction Sites,
7.3
Expected Waste
Arisings During the
Construction Phase
During the construction phase, the main
activities, which will potentially result in the generation of waste, include
clearance of vegetation, construction of sub-structures and abutments of the
new flyover, removal of existing road embankment and parapets, construction of
subway, and reprofiling of existing barriers. The typical waste types associated with
these activities include:
·
construction
waste;
·
chemical
waste;
·
sewage;
and
·
general
refuse.
It is anticipated that no waste will be
arise during the operational phase of the Project, and therefore no operational
impacts with implications on waste management is expected.
7.4.1
Construction & Demolition Materials
Construction and demolition (C&D) material
would be generated from the following works of the Project:
·
Clearance
of existing vegetation to be affected by the works;
·
Construction
of retaining wall and flyover;
·
Demolition
of existing parapets or footing for existing noise barriers;
·
Fill slope
/ slope reprofiling involved in road realignment; and
·
Extension
of subway under
The key types of
excavated and demolition materials expected to be generated during the
construction works include excavated soil, fill and concrete. The total volume of the excavated and
demolition materials currently estimated by HyD is approximately 33,000 m3. A breakdown of the estimated quantities
of excavated and demolition materials from the different types of works of the
Project is presented in Table 7.4a.
Table 7.4a Summary
of Excavation and Demolition Quantities
|
Road Segment / Associated Works |
Description of Construction Works |
Excavation Volume (m3) |
Demolition Volume (m3) |
|
|
Slip Road A |
Construction of
retaining walls |
5,200 |
150 |
|
|
|
Diverge from
existing road (road widening) |
600 |
50 |
|
|
Flyover A |
Construction of
the new flyover (including piling, pile caps and abutments) |
3,500 |
150 |
|
|
Slip Road B |
Construction of
retaining walls |
4,700 |
50 |
|
|
Slip Road C |
Construction of
retaining walls |
10,400 |
100 |
|
|
|
Reprofile existing slope |
700 |
- |
|
|
Left-turn Lane A |
Construction of retaining walls and
planter walls |
1,400 |
- |
|
|
|
Construction of subway extension |
400 |
- |
|
|
|
Removal of 1m high stem of the existing
retaining wall |
- |
100 |
|
|
|
Reconstruction of the existing road
embankment with re-provision of planter wall at slope crest |
1,000 |
- |
|
|
|
Reprofile of existing
noise barrier |
400 |
100 |
|
|
Road
Resurfacing and Remarking A |
Offsetting the
kerb, extending the crossfall and resurfacing of carriageway |
- |
100 |
|
|
Road
Resurfacing and Remarking B |
Resurfacing of
carriageway |
- |
100 |
|
|
Construction of
1m high noise barrier |
Excavation and
backfilling activities |
2,600 |
- |
|
|
Associated
drainage, sewerage, water main and utilities works |
Excavation and
backfilling activities |
500 |
100 |
|
|
Landscaping
works |
Excavation and backfilling
activities |
600 |
- |
|
|
Total
|
|
32,000 |
1,000 |
The Project would
require about 34,000 m3 of soil/granular fill and 4,000 m3
rock fill. The requirements for fill
materials will be partly met by reusing the inert excavated materials generated
from the Project itself. HyD has
estimated that about 30% of the excavated materials are suitable for reuse
on-site.
C&D materials would be generated
mainly from the excavation of the existing road embankments or slopes and a
portion of these materials could be used for re-profiling of the existing
slopes. Opportunities for reusing
the inert C&D material on-site for the retaining structures, which
constitutes a key requirement for fill materials, have also been explored but
found to be limited. As indicated
in Section 3.3.5, earth reinforced
retaining structures have been adopted for the construction of Slip Roads A and
B taking into account the potential noise impacts on the surrounding sensitive
receivers and the flexibility for working in the limited space available for
the works. Specific considerations
on the filling materials is required for the proposed earth reinforced retaining
structure to satisfy the relevant design/performance requirements, such as the
grading requirement of the selected fill.
From the information provided by available ground investigation records,
the site geology is complex and comprises fill materials, alluvium, Super-Karst
Deposit and completely decomposed rock (Metamudstone/Metasiltone
/Granodiorite). The construction
works of the Project are expected to involve mainly excavation in the in-situ
fill materials and alluvium. The
variable properties and extent of the in-situ fill materials to be excavated
and their clayey and silty properties would render them unsuitable for reuse as
filling materials in the proposed retaining structures. The estimated 30% on-site reuse of
excavated materials is therefore considered reasonable and achievable based on
the adopted engineering design and the site-specific geological information.
The surplus inert
C&D materials should be delivered to public fill facilities for reuse. Based on the trends observed in the data
published by EPD in Monitoring of Solid
Waste in Hong Kong and HyD’s experience in similar previous projects, it is
also estimated that about 10% of the demolition materials are C&D waste
which would be disposed of at landfill.
Based on the above, about 9,600 m3 of excavation materials
would be reused on site and about 23,300 m3 of inert C&D
materials would be disposed of to public fill reception facilities for other
beneficial uses. Approximately
100 m3 of non-inert materials generated from the excavation and
demolition activities and about 400 m3 of cleared vegetation would
be disposed of as C&D waste to designated landfills or refuse transfer
stations. As the engineering design
of the Project is still ongoing, HyD will continue to explore opportunities for
enhancing on-site reuse of excavated materials and for reducing the quantity of
C&D waste for landfill disposal.
HyD will maintain close liaison with EPD and the Public Fill Committee
(PFC) in this regard. Table 7.4b summarises the estimated
C&D materials arising and the associated disposal routes.
Table 7.4b Summary
of Estimated Major C&D Material Arising and
|
|
Total
Quantities Generated |
Quantities to
be Reuse on-site (a) |
Quantities to
be Reuse in Public Fill Reception Facilities |
Quantities to
be Disposed of at Landfill (b) |
|
Excavated materials |
32,000 m3 |
9,600 m3 |
22,400 m3 at Tuen Mun Area 38 Fill Bank or
other approved public fill facilities |
- |
|
Demolition materials |
1,000 m3 |
- |
900 m3 at Tuen Mun Area 38 Fill Bank or other
approved public fill facilities |
100 m3 at WENT Landfill or other approved
designated landfill sites |
|
Cleared vegetation |
400 m3 |
- |
- |
400 m3 at WENT Landfill or other approved
designated landfill sites |
|
Total |
33,400 m3 |
9,600 m3 |
23,300 m3 |
500 m3 |
|
Notes: (a)
It is anticipated that about 30% of the excavated
materials are suitable to be reuse on-site. (b)
It is anticipated that about 10% of the demolition
materials are C&D waste would be disposed of to designated
landfills. |
||||
The majority of
the C&D materials will be generated from the 4th month to the 21st
month (tentatively from March 2010 to August 2011) as a result of the
construction works for piles, retaining walls, new flyover and
embankments. A sequential
construction method will be used to facilitate the separation of inert and
non-inert materials, as far as possible, to enable the beneficial use of the
inert materials and to minimise waste disposal costs. Assuming a bulking factor of 1.4, it is
estimated that about 13 truck trips will be required each day to dispose of the
C&D materials ([1])
to the Tuen Mun Area 38 Fill
Bank or other approved designated public fill facilities. The number of truck trips required to
dispose of C&D waste to the West New Territories (WENT) Landfill or
other approved designated landfill sites will be minimal owing to the
relatively small volume of such materials expected to be generated over the
entire construction phase. The
delivery of the C&D materials to public fill reception facilities and
landfills will be monitored using a trip ticket system implemented in
accordance with ETWB TCW No. 31/2004.
7.4.2
Chemical Waste
Chemical waste, as defined under the Waste Disposal (Chemical Waste) (General)
Regulation, includes any unwanted substances specified under Schedule 1 of the Regulation. Substances
likely to be generated from the construction of the Project may include:
·
Residual
paints and solvents; and
·
Used
lubricant oil from maintenance of the construction plant.
It is anticipated that the quantity of
chemical waste to be generated will be small and in the order of a few hundred
litres for whole construction phase.
These chemical waste will be stored and disposed of in an appropriate
manner, as outlined in the Waste Disposal
(Chemical Waste) (General) Regulation and the Code of Practice on the Packaging, Labelling and Storage of Chemical
Wastes.
7.4.3
Sewage
Sewage will arise
from the construction workforce. It
is estimated that a maximum of about 120 workers will be working at the site at
any one time. The amount of sewage
to be generated will be about 7.2 m3 per day ([2]) .
An adequate number of portable toilets will be provided at the site to
ensure that sewage from site staff is properly collected. The portable toilets will be desludged
and maintained regularly by a licensed contractor. No adverse environmental impacts are
envisaged.
7.4.4
General Refuse
General refuse will be generated by the
workforce. It is expected that the
quantity of general refuse (mainly consisting of food waste, aluminium cans and
waste paper) to be generated from the site staff will therefore be small (in
the order of 78 kg per day ([3])
). Recyclable materials (ie paper, plastic
bottles and aluminium cans) will be separated for recycling, in order to reduce
the amount of general refuse to be disposed of at landfill.
The non-recyclable refuse will be placed
in bags and stored in enclosed bins, and disposed of on a daily basis. This will avoid the occurrence of wind
blown litter, odour, water quality impacts and vermin nuisance. The general refuse will be transported
to the WENT Landfill or other approved designated landfill sites for disposal. No adverse environmental impact is envisaged.
Given that the quantity of general refuse
to be disposed of at landfill is small, no adverse impact on the operation of
the station is anticipated.
7.5
Mitigation Measures
The assessment indicates that with the implementation
of the proposed waste management practices at the work sites, no adverse
environmental impacts are envisaged for the handling, collection and disposal
of waste arising from the construction of the Project. No mitigation measures will be required.
This section further describes the good
construction site practices to avoid or further reduce the potential
environmental impacts associated with the handling, collection and disposal of
construction and chemical wastes arising from the construction of the
Project.
The Contractor must ensure that all the
necessary waste disposal permits or licences are obtained prior to the
commencement of the construction works.
The Contractor should incorporate these recommendations into a Waste
Management Plan (WMP) for the construction works. The Contractor should submit the plan to
Project Proponent’s Engineer Representative for endorsement prior to the
commencement of the construction works.
The plan should incorporate site-specific factors, such as the designation
of areas for the segregation and temporary storage of reusable and recyclable
materials.
It will be the Contractor’s responsibility
to ensure that only reputable licensed waste collectors are used and that
appropriate measures to reduce adverse impacts, including windblown litter and
dust from the transportation of these wastes, are employed. In addition, the Contractor must ensure
that all the necessary permits or licences required under the Waste Disposal Ordinance are obtained
for the construction phase.
Waste
Management Hierarchy
The various waste management options are
categorised in terms of preference from an environmental viewpoint. The options considered to be most
preferable have the least environmental impacts and are more sustainable in the
long term. The hierarchy is as
follows:
·
Avoidance
and reduction;
·
Reuse
of materials;
·
Recovery
and recycling; and
·
Treatment
and disposal.
The above hierarchy has been used to
evaluate and select waste management options. The aim has been to reduce waste
generation and reduce waste handling and disposal costs.
The Contractor should consult the EPD for
the final disposal of wastes and implement the following good site practices
and mitigation measures:
Waste
Reduction Measures
Good management and control can prevent
generation of significant amount of waste.
Waste reduction is best achieved at the planning and design stage, as
well as by ensuring the implementation of good site practices. Recommendations to achieve waste
reduction include:
·
Segregation
and storage of different types of waste in different containers, skips or
stockpiles to enhance reuse or recycling of material and their proper disposal;
·
Encourage
collection of aluminium cans and waste paper by individual collectors during
construction with separate labelled bins being provided to allow the
segregation of these wastes from other general refuse generated by the
workforce;
·
Any
unused chemicals and those with remaining functional capacity be recycled as
far as possible;
·
Use
of reusable non-timber formwork to reduce the amount of C&D materials;
·
Prior
to disposal of construction waste, wood, steel and other metals should be
separated, to the extent practical for re-use and/or recycling to reduce the
quantity of waste to be disposed at landfills;
·
Proper
storage and site practices to reduce the potential for damage or contamination
of construction materials; and
·
Plan
and stock construction materials carefully to reduce amount of waste generated and
avoid unnecessary generation of waste.
7.5.1
Construction Waste
Wherever practicable, the excavated soil
will be segregated from other wastes to avoid contamination, and reused on-site
for filling to reduce the amount of construction waste to be disposed off-site.
Good site practices during the
construction activities would avoid adverse waste management related. Recommendations for good site practices
during the construction activities include:
·
Nomination
of an approved person, such as a site manager, to be responsible for good site
practices, arrangements for collection and effective disposal to an appropriate
facility, of all wastes generated at the site.
·
Training
of site personnel in proper waste management and chemical waste handling
procedures.
·
Provision
of sufficient waste disposal points and regular collection for disposal.
·
Appropriate
measures to minimise windblown litter and dust during transportation of waste
by either covering trucks or by transporting wastes in enclosed containers.
·
Regular
cleaning and maintenance programme for drainage systems, sumps and oil
interceptors.
·
A
recording system for the amount of wastes generated, recycled and disposed of
(including the disposal sites).
7.5.2
Management of Waste Disposal
The construction contractor will open a
billing account with the EPD in accordance with the Waste Disposal (Charges for Disposal of Construction Waste) Regulation. Every construction waste or public fill
load to be transferred to the Tuen Mun Area 38 Fill Bank or other approved designated
public fill facilities will require a valid “chit”.
A trip-ticket system will also be
established in accordance with Works
Bureau Technical Circular No.31/2004 to monitor the disposal of
construction waste at the Tuen Mun Area 38 Fill Bank or other approved
designated public fill facilities, and to control fly-tipping. The trip-ticket system will be included
as one of the contractual requirements and implemented by the contractor.
7.5.3
Chemical Waste
The construction contractor will be registered
as a chemical waste producer with the EPD.
Chemical waste will be handled in accordance with the Code of Practice on the Packaging, Handling
and Storage of Chemical Wastes.
Containers used for the
storage of chemical wastes should:
·
Be
suitable for the substance they are holding, resistant to corrosion, maintained
in a good condition, and securely closed;
·
Have
a capacity of less than 450 L unless the specifications have been approved by
the EPD; and
·
Display
a label in English and Chinese in accordance with instructions prescribed in
Schedule 2 of the Regulations.
The storage area for chemical wastes will:
·
Be
clearly labelled and used solely for the storage of chemical waste;
·
Be
enclosed on at least 3 sides;
·
Have
an impermeable floor and bunding, of capacity to accommodate 110% of the volume
of the largest container or 20% by volume of the chemical waste stored in that
area, whichever is the greatest;
·
Have
adequate ventilation;
·
Be
covered to prevent rainfall entering (water collected within the bund must be
tested and disposed of as chemical waste, if necessary); and
·
Be
arranged so that incompatible materials are appropriately separated.
Chemical waste should be collected by a licensed
chemical waste collector to a facility licensed to receive chemical waste, such
as the Chemical Waste Treatment Facility.
At the commencement of the construction
works, training will be provided to workers on the concepts of site cleanliness
and on appropriate waste management procedures, including waste reduction,
reuse and recycling.
7.5.5
Summary of Waste Handling Procedures and
Disposal Routes
The summary of the various waste types likely
to be generated during the construction works for the Project, together with
the recommended handling and disposal methods are summarized in Table 7.5a.
Table 7.5a Summary
of Waste Handling Procedures and Disposal Routes
|
Waste material type |
Total quantities
generated |
Quantities to be reuse
on-site |
Quantities to be disposed
off-site |
Proper handling
procedures |
Disposal |
|
C&D
Materials |
32,900
m3 of inert C&D materials and 500 m3 of C&D
waste |
9,600
m3 of inert C&D materials reuse on-site for filling |
23,300
m3 of inert C&D materials and 500 m3 of C&D
waste |
Handle
in accordance with good site practices and sorting of inert C&D material
(public fill) and C&D
waste onsite. |
Inert
C&D materials send to public filling are for other beneficial uses;
C&D waste for disposal of at landfill. |
|
Chemical
Waste |
Few
hundred litre for whole construction phase |
- |
Few
hundred litre |
Handle
in accordance with the Code of Practice
on the Packaging, Handling and Storage of Chemical Wastes and collect by
licensed chemical waste collectors. |
Chemical Waste Treatment Centre |
|
Sewage
|
7.2
m3 per day |
- |
7.2
m3 per day |
Portable
toilets will be desludged and maintained regularly by licensed contractor |
To
be collected by licensed sewage collector for treatment |
|
General
Refuse |
78
kg per day |
- |
78
kg per day |
Provide
on-site refuse collection points waste segregation. |
To
be collected by licensed waste collector for disposal of at landfill. |
7.6
Residual
Environmental Impacts
No residual waste management impact is
envisaged after the completion of the Project construction works.
Potential land contamination issues for all land
lots/sites within the Study Area are considered below. Past and present activities or land uses
that may cause land contamination problems are assessed.
The assessment is undertaken in accordance with Clause
3.4.4.2 (iii) of the EIA Study Brief,
Annex 19 of the EIAO-TM and Guidance Note for Contaminated Land
Assessment and Remediation issued by EPD
in 2007.
7.7.1
Assessment
Methodology
The objective of this assessment is to evaluate and
identify the potential land contamination associated with the past and present
activities or land uses within the Study Area and develop an assessment plan to
determine the extent of any contamination present, if required. To achieve the objective, a desktop
study to review the past and present activities or land uses within the Study
Area and an assessment on any potential environmental impacts arising as a
result of historical land contamination or during future use of the proposed
new roads were undertaken.
7.7.2
Desktop Study
A
desktop study was conducted to review past and present land uses, activities
and installations within the Study Area and its vicinity that may have the
potential to cause land contamination.
The following sources of information were collected and reviewed:
·
Hong
Kong Topographic Survey maps (1:1000, 1:5000 and 1:10,000) from 1967 to
present, Survey and Mapping Office, Lands Department;
·
·
Selected
aerial photographs of the Site and its surrounding areas from 1964 onwards; and
·
Selected
historical photographs of the Study Area and its surrounding areas in the
archives of Hong Kong Public Library (HKPL).
7.7.3
Site History
A
review of the site history was conducted based on the examination and analysis
of selected aerial photographs and survey maps of the Study Area. Selected aerial photographs taken in
1964, 1973, 1983, 1993, 1995, 1996, 1998, 2005 and 2007 and survey maps published
since 1967 of the Study Area were reviewed. A list of relevant aerial photographs
reviewed is presented in Table 7.7a.
Table
7.7a Aerial
Photographs Reviewed
|
Date of Photograph |
Lands Department Reference No. |
Height (Feet) |
Observations |
|
16 December 1964 |
3268 |
1800 |
View of Yuen Long. The Study Area was used for
agriculture. Agricultural fields
and ponds were found. |
|
20 February 1973 |
3419 |
3000 |
View of Yuen Long. The Study Area was used for
agriculture. Agricultural fields,
ponds and squatter huts were found.
|
|
26 September 1983 |
49474 |
3000 |
View of Yuen Long. The Study Area was used for
agriculture. Agricultural fields,
ponds, squatter huts and high-rise buildings were found. Foot bridge crossing |
|
28 May 1993 |
CN3435 |
3000 |
View of Pok Oi Interchange. The roundabout and slip roads to the
south of roundabout were under construction. A school was located in the
proposed Left-Turn Lane A area. |
|
19 July 1995 |
CN10237 |
3200 |
View of Pok Oi Interchange. The roundabout and slip roads to the
south of roundabout were in place. |
|
31 October 1996 |
CN15287 |
3000 |
View of Pok Oi Interchange. The slip roads to the north of the
roundabout were under construction. |
|
10 July 1998 |
CN19928 |
3000 |
View of Pok Oi Interchange. The slip roads to the north of the
roundabout were in place. Yuen Long Highway was under construction. The
school located in the proposed Left-Turn Lane A area had been demolished and
the area was used as for accommodating a construction site office. |
|
07 May 2005 |
CW65272 |
2500 |
View of Pok Oi Interchange. West Rail was in
operation. YOHO Town Phase I was occupied while Phase II was under
construction. |
|
25 July 2007 |
CW77365 |
3000 |
View of Pok Oi Interchange. |
|
Source of Aerial Photographs: Survey and Mapping Office, Lands
Department |
|||
Historically, the Study Area
was mostly agricultural fields and ponds.
Scattered squatter huts were found.
The most prominent change to the land uses within the Study Area was the
construction of POI. POI with its
slip roads and YLH have been in place since 1993 and 1998, respectively.
From the historical aerial photographs and
Hong Kong Topographic Survey maps examined, part of the area for the proposed
7.7.4
Geology and Superficial
Deposits
From
the historical photographs examined, the Study Area was shown to be within the
works boundary of YLH in 1998. The
natural solid and superficial deposits would have been disturbed by the
construction activities of YLH. It
is therefore believed that further impact from the Project on the same deposits
will be minimal.
7.7.5
Existing Land uses
According to
As
for the area for the proposed
7.7.6
Potential Impacts
The
review of past and present land uses of the Study Area indicates that the area,
except that for the proposed
For
the area in which the proposed
Based
on the above, it is anticipated that contaminated materials would not be
encountered during the construction of the Project and implications with
respect to construction worker exposure to contaminated materials and
contaminated material disposal are not expected.
7.8
Environmental
Monitoring and Audit
To facilitate monitoring and control over
the Contractor’s environmental performance in terms of waste management, a waste
monitoring and audit programme should be implemented during the construction
phase. The aims of the monitoring
and audit programme are:
·
To
review the Contractor’s Waste Management Plan (WMP) including the quantities
and types of C&D materials generated, reused and disposed of off-site; the
amount of fill materials exported from/imported to the Site and the quantity of
timber used in temporary works construction for each process/activity;
·
To
monitor the implementation and achievement of the WMP on-site to assess its
effectiveness; and
·
To
monitor the follow-up actions for deficiencies identified.
Joint site audits by the Environmental
Team and the Contractor should be undertaken on a regular basis. Particular attention should be given to
the Contractor’s provision of sufficient spaces, adequacy of resources and
facilities for on-site sorting and temporary storage of C&D material. The C&D materials to be disposed of
from the Project should be visually inspected. The public fill for delivery to off-site
stockpiling areas should contain no observable non-inert materials (eg, general
refuse, timber, etc). Furthermore,
the waste to be disposed of at refuse transfer stations or landfills should as
far as possible contains no observable inert or reusable/recyclable C&D
materials (eg, soil, broken rock, metal, and paper/cardboard packaging,
etc). Any irregularities observed
during the regular site audits should be raised promptly to the Contractor for
rectification.
To facilitate assessment of the
effectiveness of the waste management measures, the WMP should state the
performance targets to be achieved in reducing generation of C&D materials
taking account of the Site constraints.
The performance targets should cover the following items and should be
agreed with HyD at the beginning of the Contract.
·
The
percentage of excavated materials to be sorted to recover the soil and broken
rock for reuse on site or deliver to the off-site stockpiling area;
·
The
percentage of metal to be recovered for collection by recycling contractors;
and
·
The
percentage of cardboard and paper packaging (for plant, equipment and
materials) to be recovered. The
recovered materials will be properly stockpiled in dry and covered condition to
prevent cross contamination by other wastes.
The findings of the waste audits should be
reported in regular Environmental Monitoring and Audit (EM&A) Reports.
The quantities of construction waste,
chemical wastes, sewage and general refuse to be generated during the
construction phase of the Project are expected be small. With the implementation of general good
construction site practices, the construction of the Project will not cause
adverse waste management or environmental impacts. Waste arisings, which are expected to
comprise silt or grit removed from road gullies and litter collected from road
surface, during the operational phase will be minimal and will not cause any
environmental impact.
Based on the desktop studies and site inspection
undertaken, no contaminated sites were identified in the vicinity of the
Project. A small area in which the
proposed
([1])
Trucks per day = 23,300 m3 of C&D materials to be disposed offsite x bulk
factor 1.4 / 18 months / 24 days per month / 6 m3 per truck = 12.5