14.       SCHEDULE OF RECOMMENDED MITIGATION MEASURES

 

Table 14-1       Schedule of Recommended Mitigation Measures

 

14.  SCHEDULE OF RECOMMENDED MITIGATION MEASURES

 

Table 14-1  Schedule of Recommended Mitigation Measures

 

EM&A

Ref.

EIA

Ref.

Control/Mitigation Measures

Location

Timing for Implementation

Implementation Agent

Requirements

Air Quality

S.2.2

S.3.3.6

The construction works at the Pui O tunnel portal if no mitigation measures are in place, are likely to cause dust impact on the nearby ASR. However, the construction dust impact can be reduced to an acceptable level with the implementation of dust control measures. Both general and specific mitigation measures are recommended to ensure no adverse air quality impact during construction phase.

 

Work site

During construction

CLP’s Contractor

Air Pollution Control (Construction Dust) Regulation

 

 

Specific

 

Dust suppression efficiency of 50% can be achieved by applying watering twice a day.

 

 

 

 

 

 

 

 

 

 

 

 

 

General

 

The following control measures are stipulated in the Air Pollution Control (Construction Dust) Regulation and should be implemented to minimise the dust nuisance.

 

 

 

 

 

 

 

 

 

 

 

 

 

·         the stockpile should be properly treated and sealed with latex, vinyl, bitumen or other suitable surface stabiliser if a stockpile of dusty materials is more than 1.2m but less than 2m high and lies within 50m from any site boundary that adjoins a road, street, or other area accessible to the public;

 

 

 

 

 

 

 

 

 

 

 

 

 

·        effective dust screens, sheeting or netting should be provided to enclose the scaffolding from the ground floor level of the building or if a canopy is provided at the first floor level, from the first floor level, up to the highest level of the scaffolding where a scaffolding is erected around the perimeter of a building under construction;

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

·         dump truck for material transport should be totally enclosed by impervious sheeting;

 

 

 

 

 

 

 

 

 

 

 

 

 

·         any excavated dusty materials or stockpile of dusty materials should be covered entirely by impervious sheeting or sprayed with water so as to maintain the entire surface wet, and recovered or backfilled or reinstated within 24 hours of the excavation or unloading;

 

 

 

 

 

 

 

 

 

 

 

 

 

·         stockpile of dusty materials should not extend beyond the pedestrian barriers, fencing or traffic cones;

 

 

 

 

 

 

 

 

 

 

 

 

 

·         dusty materials remaining after a stockpile is removed should be wetted with water and cleared from the surface of roads;

 

 

 

 

 

 

 

 

 

 

 

 

 

·         vehicle washing facilities should be provided at every vehicle exit point;

 

 

 

 

 

 

 

 

 

 

 

 

 

·         the area where vehicle washing takes place and the section of the road between the washing facilities and the exit point should be paved with concrete, bituminous materials or hardcores;

 

 

 

 

 

 

 

 

 

 

 

 

 

·         where a site boundary adjoins a road, streets or other area accessible to the public, hoarding of not less than 2.4m high from ground level should be provided along the entire length except for a site entrance or exit;

 

 

 

 

 

 

 

 

 

 

 

 

 

·         every main haul road should be scaled with concrete and kept clear of dusty materials or sprayed with water so as to maintain the entire road surface wet;

 

 

 

 

 

 

 

 

 

 

 

 

 

·         the portion of road leading only to a construction site that is within 30m of a designated vehicle entrance or exit should be kept clear of dusty materials;

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

·         every stock of more than 20 bags of cement should be covered entirely by impervious sheeting or placed in an area sheltered on the top and the 3 sides;

 

 

 

 

 

 

 

 

 

 

 

 

 

·         loading, unloading, transfer, handing or storage of bulk cement or any cement during or after the de-bagging process should be carried out in a totally enclosed system or facility, and any vent or exhaust should be fitted with an effective fabric or equivalent air pollution control system or equipment;

 

 

 

 

 

 

 

 

 

 

 

 

 

·         cement, or any other dusty materials collected by fabric filters or other air pollution control system or equipment should be disposed of in totally enclosed containers;

 

 

 

 

 

 

 

 

 

 

 

 

 

·         stockpile of dusty materials should be either covered entirely by impervious sheeting, placed in an area sheltered on the top and the 3 sides; or sprayed with water so as to maintain the entire surface wet;

 

 

 

 

 

 

 

 

 

 

 

 

 

·         all dusty materials should be sprayed with water prior to any loading, unloading or transfer operation so as to maintain the dusty material wet;

 

 

 

 

 

 

 

 

 

 

 

 

 

·         vehicle speed should be limited to 10 kph except on completed access roads;

 

 

 

 

 

 

 

 

 

 

 

 

 

·         every vehicle should be washed to remove any dusty materials from its body and wheels before leaving the construction sites;

 

 

 

 

 

 

 

 

 

 

 

 

 

·         the load of dusty materials carried by vehicle leaving a construction site should be covered entirely by clean impervious sheeting to ensure that the dusty materials do not leak from the vehicle;

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

·         the working area of excavation should be sprayed with water immediately before, during and immediately after the operations so as to maintain the entire surface wet;

 

 

 

 

 

 

 

 

 

 

 

 

 

Blasting of Works

 

·         the area within 30m from the blasting area should shall be wetted with water prior to blasting; and

 

 

 

 

 

 

 

 

 

 

 

 

 

·         blasting should shall not be carried out when the strong wind signal or tropical cyclone warning signal No. 3 or higher is hoisted unless prior permission of the Commissioner of Mines is obtained.

 

 

 

 

 

 

 

 

 

 

 

 

 

·         wire mesh, gunny sacks and sandbags should be used on top of the blast area at each shot to prevent flying rock and dust;

 

 

 

 

 

 

 

 

 

 

 

 

 

·        water the surface of the blast area to increase its moisture content;

 

 

 

 

 

 

 

 

 

 

 

 

 

·        dust filters should be fitted to the tunnel construction ventilation systems;

 

 

 

 

 

 

 

 

 

 

 

 

 

·        vents of all silos and weighing scale shall be fitted with fabric filtering system; and

 

 

 

 

 

 

 

 

 

 

 

 

 

·         seating of pressure relief valves of all silos shall be checked, and the valves resealed if necessary, before each delivery.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Noise

S.3.3.1

S.3.4.6

Good Site Practice

 

·            only well-maintained plant should be operated on-site and plant should be serviced regularly during the construction works;

·            machines and plant that may be in intermittent use should be shut down between work periods or should be throttled down to a minimum;

·            plant known to emit noise strongly in one direction, should, where possible, be orientated to direct noise away from the NSRs;

·            mobile plant should be sited as far away from NSRs as possible; and

·            material stockpiles and other structures should be effectively utilised, where practicable, to screen noise from on-site construction activities.

 

Work Site

During construction

CLP’s Contractor

PN 2/93 & EIAO

S.3.3.2

S.3.4.6

Selecting Quieter Plant and Working Methods

 

·         Application of properly designed silencers, mufflers, acoustically dampened panels and acoustic sheds or shields, etc.;

Work Site

During construction

CLP’s Contractor

PN 2/93 & EIAO

 

 

·         Use of electric-powered equipment where applicable instead of diesel-powered or pneumatic-powered equipment;

 

 

 

 

 

 

·         Erecting noise enclosures around noisy plants;

 

 

 

 

 

 

·         Location of noise emitting plants at maximum possible distances from sensitive receivers;

 

 

 

 

 

 

·         Contractual clauses for construction works;

 

 

 

 

 

 

·         Schedule of noisy operations during non-restricted hours;

 

 

 

 

 

 

·         Regular maintenance of site plant/ equipment; and

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

S.3.3.2

S.3.4.6

Selecting Quieter Plant and Working Methods

 

·            Application of properly designed silencers, mufflers, acoustically dampened panels and acoustic sheds or shields, etc.;

·            Use of electric-powered equipment where applicable instead of diesel-powered or pneumatic-powered equipment;

·            Erecting noise enclosures around noisy plants;

·            Location of noise emitting plants at maximum possible distances from sensitive receivers;

·            Contractual clauses for construction works; and

·            Schedule of noisy operations during non-restricted hours;

·            Regular maintenance of site plant/ equipment.

·            A temporary cantilevered barriers of 4m high is proposed to be erected at the tunnel portal area in order to alleviate the construction noise impact by blocking the line of view from the nearby receivers. The barrier material needs to have a surface density (> 7 kg/m2) to provide sufficient screening effect (approx. 10 dB(A)).

 

Work Site

During construction

CLP’s Contractor

PN 2/93 & EIAO

S.3.3.2

S.3.4.6

Mitigation Measures during blasting of works (Specific)

 

·         Tunnel portal doors should be closed when the construction activities carried out within the tunnel.

 

Work Site

During construction

CLP’s Contractor

PN 2/93 & EIAO

Ground Water

S.3.54.10.2

S.3.5.1

Mitigation Measures

 

In case any substantial and abnormal changes in the ground water table are observed from the monitoring point as a result of groundwater inflow into the proposed cable tunnel, mitigation measures as outlined below are recommended to prevent further groundwater loss.  The mitigation measures include:-

 

·         traditional pre-injection systems using cement grout will be applied in the identified fault intersection zone to reduce the water inflow, if necessary; and

 

·         apply 2mm thick typical high performance PVC waterproof membrane and geotextile fleece mats as suggested in the tunnel preliminary design report to ensure watertighteness of the tunnel.

 

Work Site

During construction

CLP’s Contractor

-

Water Quality

S.4.8

S.4.6

General Mitigation Measures

 

·         All waste water generated on the site shall be collected, removed from site via a suitable and properly designed temporary drainage system and disposed of at a location and in a manner that will cause neither pollution nor nuisance;

Work site

During construction

CLP’s Contractor

Practice Note for Professional Persons with regard to site drainage (ProPECC PN 1/94)

 

 

·         The Contractor should construct, maintain, remove and reinstate, as necessary, temporary drainage works and take all other precautions necessary for the avoidance of damage by flooding and silt washed down from the works. The Contractor should also provide adequate precautions to ensure that no spoil or debris of any kind is allowed to be pushed, washed down, fall or be deposited on land or on the seabed adjacent to the site;

 

 

 

 

 

 

·         The Contractor should not permit any sewage, waste water or other effluent containing sand, cement, silt or any other suspended or dissolved material to flow from the site onto any adjoining land or allow any solid waste to be deposited anywhere within the site or onto any adjoining land and shall have all such materials removed from the site;

 

 

 

 

 

 

·         The Contractor should be responsible for temporary drainage, diverting or conducting of open streams or drains intercepted by any works and for reinstating these do their original courses on completion of the works;

 

 

 

 

S.4.8

S.4.6

General Mitigation Measures

 

·        All waste water generated on the site shall be collected, removed from site via a suitable and properly designed temporary drainage system and disposed of at a location and in a manner that will cause neither pollution nor nuisance;

·        The Contractor should construct, maintain, remove and reinstate, as necessary, temporary drainage works and take all other precautions necessary for the avoidance of damage by flooding and silt washed down from the works. The Contractor should also provide adequate precautions to ensure that no spoil or debris of any kind is allowed to be pushed, washed down, fall or be deposited on land or on the seabed adjacent to the site;

·        The Contractor should not permit any sewage, waste water or other effluent containing sand, cement, silt or any other suspended or dissolved material to flow from the site onto any adjoining land or allow any solid waste to be deposited anywhere within the site or onto any adjoining land and shall have all such materials removed from the site;

·        The Contractor should be responsible for temporary drainage, diverting or conducting of open streams or drains intercepted by any works and for reinstating these do their original courses on completion of the works;

·        Any proposed temporary diversions to stream courses or nullahs shall be submitted to the Engineer for agreement one month prior to such diversion works being commenced. Diversions shall be constructed to allow the water flow to discharge without overflow, erosion or washout. The area through which the temporary diversion runs is to be reinstated to its original condition when the temporary diversions is no longer required;

 

Work site

During construction

CLP’s Contractor

Practice Note for Professional Persons with regard to site drainage (ProPECC PN 1/94)

S.4.8

S.4.6

·         The Contractor shall not discharge directly or indirectly (by runoff) or cause or permit to be discharged into any public sewer, storm-water drain, channel, stream-course or sea, any effluent or foul or contaminated water or cooling water without the prior consent of the relevant Authority who may require the Contractor to provide, operate and maintain at the Contractor’s own expense, within the premises or otherwise, suitable works for the treatment and disposal of such effluent or foul or contaminated or cooling or hot water;

 

Work site

During construction

CLP’s Contractor

Practice Note for Professional Persons with regard to site drainage (ProPECC PN 1/94)

 

 

·         The Contractor shall at all times ensure that all existing stream courses and drains within, and adjacent to the site are kept safe and free from any debris and any excavated materials arising from the works. The Contractor shall ensure that chemicals and concrete agitator washings are not deposited in watercourses; and

 

 

 

 

S.4.8

S.4.6

·         All Contractor’s equipment shall be designed and maintained to minimise the risk of silt and other contaminants being released into the water column or deposited in other than designated locations.

The Contractor shall not discharge directly or indirectly (by runoff) or cause or permit to be discharged into any public sewer, storm-water drain, channel, stream-course or sea, any effluent or foul or contaminated water or cooling water without the prior consent of the relevant Authority who may require the Contractor to provide, operate and maintain at the Contractor’s own expense, within the premises or otherwise, suitable works for the treatment and disposal of such effluent or foul or contaminated or cooling or hot water;

·The Contractor shall at all times ensure that all existing stream courses and drains within, and adjacent to the site are kept safe and free from any debris and any excavated materials arising from the works. The Contractor shall ensure that chemicals and concrete agitator washings are not deposited in watercourses; and

·All Contractor’s equipment shall be designed and maintained to minimise the risk of silt and other contaminants being released into the water column or deposited in other than designated locations.

 

Work site

During construction

CLP’s Contractor

Practice Note for Professional Persons with regard to site drainage (ProPECC PN 1/94)

S.4.8-

S.4.6

General Pollution Prevention Measures to be Adopted During Dredging

 

·         use of closed and sealed grabs to be used to reduce sediment release rate by at least 50%;

·         mechanical grabs shall be designed and maintained to avoid spillage and shall seal tightly while being lifted; all vessels shall be sized such that adequate clearance is maintained between vessels and the sea bed at all states of the tide to ensure that undue turbidity is not generated by turbulence from vessel movement or propeller wash;

·         dredging rate must be lower than 547m3/day during dry season;

·         dredging rate must be lower than 328m3/day during wet season (if three trenches dredged simultaneously);

·         all barges shall be fitted with tight fitting seals to their bottom openings to prevent leakage of materials;

·         excess material shall be cleaned from the decks and exposed fittings of barges before the vessel is moved;

mechanical grabs shall be designed and maintained to avoid spillage and shall seal tightly while being lifted; all vessels shall be sized such that adequate clearance is maintained between vessels and the sea bed at all states of the tide to ensure that undue turbidity is not generated by turbulence from vessel movement or propeller wash;

Work site

During construction

CLP’s Contractor

WQOsPractice Note for Professional Persons with regard to site drainage (ProPECC PN 1/94)

 

 

all barges shall be fitted with tight fitting seals to their bottom openings to prevent leakage of material;

 

 

 

 

S.4.8-

S.4.6

·         loading of barges and hoppers shall be controlled to prevent splashing of dredged material to the surrounding water and barges or hoppers shall not be filled to a level which will cause overflowing of material or polluted water during loading or transportation;

 

Work site

During construction

CLP’s Contractor

WQOsPractice Note for Professional Persons with regard to site drainage (ProPECC PN 1/94)

 

 

·         the Engineer may monitor any or all vessels transporting material to ensure that no dumping outside the approved location takes place.  The Contractor shall provide all reasonable assistance to the Engineer for this purpose;

 

 

 

 

 

 

·         all vessels used for marine works must be currently registered as such with the marine department; and

 

 

 

 

 

 

·         water quality monitoring shall be carried out by the Contractor during the dredging.  Requirements and extent of monitoring will be agreed with DEP and the Engineer.

 

 

 

 

 

 

 

 

 

 

 

S.4.8--

S.4.6S.4.6

Specifically: the following control measures for dredging may also apply in the event that dredging is proposed:

 

·         dredging works should be scheduled to take place during the dry season wherever possible; and

·         dredging rate should be lower than 328 m3/day during wet season.

In addition to the foregoing general protection measures the following control measures for dredging may also apply when exceedances of SS levels at the monitoring locations are identified:loading of barges and hoppers shall be controlled to prevent splashing of dredged material to the surrounding water and barges or hoppers shall not be filled to a level which will cause overflowing of material or polluted water during loading or transportation;

·the Engineer may monitor any or all vessels transporting material to ensure that no dumping outside the approved location takes place.  The Contractor shall provide all reasonable assistance to the Engineer for this purpose;

·all vessels used for marine works must be currently registered as such with the marine department; and

·water quality monitoring shall be carried out by the Contractor during the dredging.  Requirements and extent of monitoring will be agreed with DEP and the Engineer.

 

 

Work siteWork site

During constructionDuring construction

CLP’s ContractorCLP’s Contractor

WQOsPractice Note for Professional Persons with regard to site drainage (ProPECC PN 1/94)Practice Note for Professional Persons with regard to site drainage (ProPECC PN 1/94)

S.4.8

S.4.6

General Pollution Prevention Measures to be Applied During Direct Burying

 

·         other than exerting due care when carrying out the works, direct burying can be carried out without any special mitigation measures being required to protect sensitive receivers regardless of the tide or season.rates of burying can be carried out at up to 400m/day without any adverse impact being detected at water sensitive receivers.

Work site

During construction

CLP’s Contractor

WQOsPractice Note for Professional Persons with regard to site drainage (ProPECC PN 1/94)

 

 

between completing one direct burying activity and commencing the next a rest period of 6 hours should be observed to allow the sediment levels to reduce to pre-works levels.

 

 

 

 

S.4.8

S.4.6

General Pollution Prevention Measures to be Applied During Placing of Cables in Cheung Chau Typhoon Shelter

 

·         use of silt screens may be required, either side of the cable laying if the placing of cables causes elevation in suspended solids in excess of 30% above the ambient level as defined through the baseline water quality monitoring data. For the purposes of this assessment this is assumed to be 3.9 mg/L.

 

 

Work site

During construction

CLP’s Contractor

WQOs

 

 

 

 

 

 

 

S.4.8

S.4.6

General Water Pollution Prevention Measures to be Applied if TBM’s Used

 

·         all wastewater generated must be treated to the appropriate standard given in the TM on “Standards for Effluents Discharged into Drainage and Sewerage Systems, Inland and Coastal Waters”.

Work site

During construction

CLP’s Contractor

TM & EIAO

 

 

·         in the event that conventional sedimentation techniques are inadequate to treat wastewater generated, consideration should be given to use of alternative techniques such as mobile microfiltration plants.

 

 

 

 

 

 

 

 

 

 

 

S.4.8

S.4.6

General Pollution Prevention Measures to be Adopted if Drill and Blast Method is Adopted

 

·         all wastewater generated must be treated to the appropriate standard given in the TM on “Standards for effluents Discharged into Drainage and Sewerage Systems, Inland and Coastal Waters”.

Work site

During construction

CLP’s Contractor

TM & EIA

 

 

·         in the event that conventional sedimentation techniques are inadequate to treat wastewater generated, consideration should be given to use of alternative techniques such as mobile microfiltration plants.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

-

S.4.6

 

 

 

 

 

 

 

 

 

 

In addition to the foregoing general protection measures the following control measures for dredging may also apply when exceedances of SS levels at the monitoring locations are identified:

 

·use of closed and sealed grabs to reduce release rate by at least 50%;

·if programme permits schedule dredging works during dry season;

·control release of suspended sediments to achieve 50% reduction; and

·dredging one trench at a time.

 

Work site

During construction

CLP’s Contractor

Practice Note for Professional Persons with regard to site drainage (ProPECC PN 1/94)

Terrestrial Ecology

S.6.2.1

S.6.3.5

The following mitigation measures to minimise disturbance due to the project are recommended below.

               

·       Prevent stream sedimentation during construction, particularly tunnel construction, by erection of sediment barriers and operation of stilling ponds in streams which could be potentially affected.

·       Erect fences along the boundary of construction sites before the commencement of works to prevent tipping, vehicle movements, and encroachment of personnel into adjacent areas, particularly streams S1 to S4, forest beside the Pui O portal, Pui O Marsh and Pui O Taro Bed.

·       Regularly check the work site boundaries to ensure that they are not exceeded and that no damage occurs to surrounding areas.

·       Treat any damage that may occur to individual major trees in the adjacent area with surgery.

·       Reinstate temporary work sites/disturbed areas immediately after completion of the construction by on-site tree/shrub planting.  Tree/shrub species used should take reference from those in the surrounding area.

·       Prohibit and prevent open fires within the site boundary during construction and provide temporary fire fighting equipment in the work areas, particularly close to forest areas.

 

Work Site

During Construction

CLP’s Contractor

CLP will be responsible for the funding, management and maintenance of these proposed mitigation measures.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Marine Ecology

S.6.2.2

S.6.4.5

Construction Phase

 

The marine ecological assessment indicates that during construction works the potential impacts to marine ecological assemblages are environmentally acceptable and no marine ecology specific mitigation measures are required.  Constraints on controlling impacts to water quality to within acceptable levels during construction are expected to also control impacts to marine ecology.  In accordance with the guidelines in the EIA-TM on marine ecology impact assessment the general policy for mitigating impacts to marine ecological resources, in order of priority, are:

Work Site

During Construction

CLP’s Contractor

CLP will be responsible for the funding, management and maintenance of these proposed mitigation measures.

 

 

 

 

 

 

 

 

 

·         Avoidance:  Potential impacts should be avoided to the maximum extent practicable by adopting suitable alternatives;

 

 

 

 

 

 

 

 

 

 

 

 

 

·         Minimisation:  Unavoidable impacts should be minimised by taking appropriate and practicable measures such as constraints on intensity of works operations or timing of works operations; and

 

 

 

 

 

 

 

 

 

 

 

 

 

·         Compensation:  The loss of important species and habitats may be provided for elsewhere as compensation.  Enhancement and other conservation measures should always be considered whenever possible.

 

 

 

 

 

 

 

 

 

 

 

 

 

As discussed, it has indicated that the following habitats within the Study Area will be lost:

 

 

 

 

 

 

 

 

 

 

 

 

 

·         Low Ecological Value - 0.018 ha of intertidal shore at Pui O as a result of provision of temporary working platform, but this will be resinstated following completion of the excavation of the tunnel;

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

·         Low Ecological Value - 0.5 ha of subtidal soft bottom benthos as a result of providing the concrete indication layer over the cable.  This will be re-established by natural sedimentation over time;

 

 

 

 

 

 

 

 

 

 

 

 

 

·         Medium Ecological Value - small narrow areas of rocky shores as a result of cable landing works.

 

 

 

 

 

 

 

 

 

 

 

S.6.2.2

S.6.4.5

The habitats to be lost due to the construction activities associated with the proposed Project are small in area and of low or medium ecological value.  Given that constraints on controlling impacts to water quality to within acceptable levels during construction can control impacts on marine ecology, no mitigation measures for marine ecological resources are required.  It is expected that over time rocky shore organisms will colonise the concrete covered cable trough and similar communities will be re-established.

Work Site

During Construction

CLP’s Contractor

CLP will be responsible for the funding, management and maintenance of these proposed mitigation measures.

 

 

 

 

 

 

 

Cultural Heritage

S.7.2

S.7.6

The indirect air and noise impact on Pui O Tin Hau Temple will require consultation with villagers to identify peak visiting periods to the temple, such as festival days, to avoid construction works to be undertaken at those times.

 

In order to avoid reaching the core area of the sandbar at Pui O Public School area (Site A), it is recommended to keep the circuit alignment as east as possible at the margin of the sandbar near the junction between South Lantau Road and Chi Ma Wan Road to minimise the direct impact.  It is also recommended that the trench to be dug out to lay the cable should follow the existing road and does not penetrate into the ‘no-dig’ zone as defined by AMO to avoid reaching the original ground surface which may contain the cultural remains from the lime kilns.

Work Site

During Construction

CLP’s Contractor

CLP will be responsible for the funding, management and maintenance of these proposed mitigation measures.

 

A qualified archaeologist may be required to undertake the monitoring.

 

 

 

 

 

 

 

 

 

With regard to the direct impact on the inner raised beach at Pui O (Site B), it is recommended that the detail design of the underground cable construction should not allow any disturbance of the Tang dynasty layer (4.38 - 4.9 mPD), which is 1.5 m from existing ground level (6.2 - 6.9 mPD) within this section.

 

 

 

 

 

 

 

 

 

 

 

 

 

The future levels of the proposed Chi Ma Wan Road widening implemented by Highways department need to be carefully designed to allow for the minimum 1000 mm cover for the cables, which shall be laid above the Tang dynasty layer or the `no dig’ zone as defined by AMO.  If the cover requirement cannot be achieved, approval from Highway Department should be sought in advance for allowing the cables to be laid in a shallow depth with additional protection such as concrete surround to protect the cables.

 

 

 

 

 

 

 

 

 

 

 

Landscape & Visual Impact

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Landscape & Visual Impact

 

 

 

 

S.8.2

S.8.8.1

Landscape Mitigation Measure 1 (LMM1)

Construction Programming and Works Areas

 

The construction programme for the Project should be reduced to the shortest possible period and should be executed in phases, particularly in those locations where severe or high landscape and visual impacts are expected such as Pui O tunnel portal.  Additionally, the extent and periphery of the works areas should be managed so that they are as small as possible and do not appear cluttered, untidy and unattractive, particularly to pedestrians and people undertaking recreation activities in the Country Parks, beach and Cheung Chau Promenade.  Temporary hoarding barriers should be of a recessive visual appearance in both colour and form. Measures should be implemented during construction to store materials in areas with the least obstruction to residents, pedestrians and traffic and cover all material stockpiles with impermeable material and sandbagging diversions around exposed soil. The temporary working platform area at the Pui O portal is required for stockpiles from construction of the tunnel portal.  Topsoil will also be stockpiled and used in the reinstatement of the disturbed coastline after construction. And those stockpiles should not be more than 2m high.

Work site

During construction

CLP’s Contractor

CLP will be responsible for the funding, management and maintenance of these proposed mitigation measures.

 

 

 

 

 

 

 

S.8.2

S8.8.2

Landscape Mitigation Measure 2 (LMM2)

Advanced Transplantation and Planting Works 

 

Where possible, the transplantation of existing valuable trees affected by the proposed works and new compensatory planting works; should be carried out as early as possible in the construction period instead of at the end.  This will allow the maximum time for maintenance, resulting in a higher success rate for the survival of transplanted trees and the early establishment of new screen trees and compensatory planting.

 

The protected orchid species, Aphyllorchis montana which was found in the area of the Pui O Tunnel Portal (Section2a) should be temporarily moved to a new location on site and carefully monitored and maintained.  Following completion of the construction works they should be reinstated in a condition and suitable location as near as possible to the original habitat.

The protected orchid species, Aphyllorchis montana which was found in the proposed Pui O Tunnel Portal (Section2a) is proposed to be transplanted.

Work site

During construction

CLP’s Contractor

CLP will be responsible for the funding, management and maintenance of these proposed mitigation measures.

 

 

In compensation for the disturbance, a planting reinstatement scheme will be implemented.  It will comprise replanting 750m2 of the Pui O tunnel portal area and 700 m2 of the Tai Long Wan landfall area with similar tree species to those found in the existing environs, on a minimum 1 to 1 basis, a matrix of nursery stock seedlings and transplants are proposed at a rate of 1/m2. A 24-month maintenance (i.e. defects liability) period will also be needed to ensure transplantation in successful.

 

 

 

 

 

 

 

 

 

 

 

S.8.2

S.8.8.3

Landscape Mitigation Measure 3 (LMM3)

Colour Finishes of Ancillary Elements

 

The design of the tunnel portal, and landfall areas should incorporate materials, details and textures so as to be as visually recessive as possible and in a style that fits with the surrounding rural setting. Colour should be of low chromatic intensity to reduce the potential contrast between the structures and their background. External finishing of the tunnel portal and landfall area will be designed in conjunction with the landscape scheme.  Considering these two elements in tandem will integrate and improve the visual mitigation of the overall proposed works. Where possible the use of visually permeable security fencing is recommended. This type of fencing will help to reduce the level of visual impact of the portal building by maximising the ground width available for planting. Grass-Crete planter incorporated onto the roof of the portal.

Work site

During construction

CLP’s Contractor

CLP will be responsible for the funding, management and maintenance of these proposed mitigation measures.

 

 

 

 

 

 

 

S.8.2

S.8.8.4

Landscape Mitigation Measure 4 (LMM4)

Reinstatement of Planting and Shoreline

 

The works areas at both Pui O and Tai Long Wan Tunnel portals should be restored to their previous condition, including the re-creation of natural and rocky shoreline, footpath and re-establishment of disturbed vegetation. Topsoil dredged out during construction of the tunnel will be used in restatement of the disturbed coastline. Where mature trees are felled that are considered high in environmental amenity, a replacement semi-mature tree should be planted. Existing trees cleared by construction activity should be replaced so that there is a net gain in tree numbers after the project is completed.

Work site

During construction

CLP’s Contractor

CLP will be responsible for the funding, management and maintenance of these proposed mitigation measures.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Waste Management

 

 

 

 

S.9.2

S.9.5

General Requirements

 

Detailed Design Stage

·         maximising the opportunity for re-use of excavated materials for example, forming the temporary working platform;

·         Provide treatments for converting unsuitable excavated materials for use in other purpose e.g. upgrading of subsoil to topsoil by mixing with compost;

·         providing an area within the construction site to allow for sorting and segregation of materials.

Work site

During construction

CLP’s Contractor

Practice Note for Authorised Person and Registered Structural Engineers, Building Department

Waste Disposal Ordinance(Cap 354), Waste Disposal (Chemical Waste) (General) Regulation (Cap 354), the Land (Miscellaneous Provision) Ordinance (Cap 28);

 

 

Construction Stage

·         minimisation of waste generation for disposal (via reduction/recycling/re-use);

·         segregating waste materials according to type to facilitate re-use and recycling;

·         separation of inert construction and demolition materials for either re-use on-site or use as public fill;

·         during demolition works, segregating materials at source as far as practical;

·         co-ordinate material deliveries to site in order to minimise storage times on site and the likelihood of causing damage;

·         training site staff in waste minimisation practices;

·         transport of wastes off site as soon as possible;

·         maintain enance aof comprehensive accurate waste records;

·         use of re-useable metal hoardings / signboards;

·         no on-site burning will be permitted;

·         follow the practice set out in WBTC No.5/99 “Trip-ticket System for Disposal of construction and Demolition Material”.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

S.9.2

S.9.5

Cleared vegetation from site clearance

 

·         segregationion  of materials to facilitate disposal;

·         segregation of excavated topsoil from roots and re-use for the landscaping works to minimise the volume of waste requiring off-site disposal.

Work site

During construction

CLP’s Contractor

Works Branch Technical Circular (WBTC) No. 5/98, Onsite Sorting of Construction Waste on Demolition Sites

 

 

 

 

 

 

 

S.9.2

S.9.5

Demolition waste

 

·         segregation of materials to facilitate disposal;

·         appropriate stockpile management;

·         follow the practice set out in WBTC No.5/98 “On site Sorting of Construction Waste on Demolition Sites”.

Work site

During construction

CLP’s Contractor

Works Branch Technical Circular (WBTC) No. 5/98, Onsite Sorting of Construction Waste on Demolition Sites

 

 

 

 

 

 

 

S.9.2

S.9.5

Excavated materials

 

·         segregation of materials to facilitate disposal / reuse;

·         appropriate stockpile management;

·         re-use of excavated material on or off site (where possible);

·         special handling and disposal procedures in the event that contaminated materials are excavated;

·         follow the practice set out in WBTC No.5/99 “Trip-ticket System for Disposal of construction and Demolition Material”.

Work site

During construction

CLP’s Contractor

Works Branch Technical Circular (WBTC) No. 5/98, Onsite Sorting of Construction Waste on Demolition Sites

 

 

 

 

 

 

 

 

 

 

 

 

 

 

S.9.2

S.9.5

Construction waste

 

·         segregation of materials to facilitate recycling/reuse (within designated area and in appropriate containers/stockpiles);

·         appropriate stockpile management;

·         planning and design considerations to reduce over ordering and waste generation;

·         recycling and re-use of materials where possible (e.g. metal, wood from hoardings, formwork);

·         for material which cannot be re-used/recycled, collection should be carried out by an approved waste contractor for landfill disposal;

·         follow the practice set out in WBTC No.5/98 “On site Sorting of Construction Waste on Demolition Sites”.

Work site

During construction

CLP’s Contractor

Works Branch Technical Circular (WBTC) No. 5/98, Onsite Sorting of Construction Waste on Demolition Sites

 

 

 

 

 

 

 

S.9.2

S.9.5

Chemical Waste

 

·         storage within locked, covered and bunded area;

·         the storage area should not be located adjacent to sensitive receivers e.g. drains;

·         minimise waste production and recycle oils/solvents where possible;

·         a spill response procedure should be in place and absorption material available for minor spillages;

·         use appropriate and labelled containers;

·         educate site workers on site cleanliness/waste management procedures;

·         if chemical wastes are to be generated, the contractor must register with EPD as a chemical waste producer;

·         collection by a licensed chemical waste collector.

Work site

During construction

CLP’s Contractor

Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes, EPD

 

 

 

 

 

 

 

S.8.2

S.8.8.1

Landscape Mitigation Measure 1 (LMM1)

Construction Programming and Works Areas

 

The construction programme for the Project should be reduced to the shortest possible period and should be executed in phases, particularly in those locations where severe or high landscape and visual impacts are expected such as Pui O tunnel portal.  Additionally, the extent and periphery of the works areas should be managed so that they are as small as possible and do not appear cluttered, untidy and unattractive, particularly to pedestrians and people undertaking recreation activities in the Country Parks, beach and Cheung Chau Promenade.  Measures should be implemented during construction to prevent soil erosion, such as temporary drainage around excavations, covering of topsoil stockpiles with impermeable material and sandbagging diversions around exposed soil. Temporary hoarding barriers should be of a recessive visual appearance in both colour and form. Measures should be implemented during construction to store materials in areas with the least obstruction to residents, pedestrians and traffic and cover all material stockpiles with impermeable material and sandbagging diversions around exposed soil.

 

Work site

During construction

CLP’s Contractor

CLP will be responsible for the funding, management and maintenance of these proposed mitigation measures.

Waste Management

S.9.2

S.9.5

Municipal Waste

 

·         waste should be stored within a temporary refuse collection facility, in appropriate containers prior to collection and disposal;

·         regular, daily collections are required by an approved waste collector;

·         provide sanitary facilities.

·waste should be stored within a temporary refuse collection facility, in appropriate containers prior to collection and disposal

·regular, daily collections are required by an approved waste collector

 

Work site

During construction

CLP’s Contractor

CLP will be responsible for the funding, management and maintenance of these proposed mitigation measures.

S.9.2

S.9.5

Operational Waste

 

·         wastes should be stored within a designated storage area;

·         waste such as material wrapping should be segregated into recyclable, non recyclable and putrescible wastes, where possible to facilitate disposal.

Work area

During operation

CLP’s Contractor

CLP will be responsible for the funding, management and maintenance of these proposed mitigation measures.