11               IMPLEMENTATION SCHEDULE OF THE PROPOSED MITIGATION MEASURES

Table 11.1       Implementation Schedule for Construction Dust Control

EIA Ref #

Environmental Protection Measures / Mitigation Measures

Location / Timing

Implementation Agent

Implementation Stages*

Relevant Legislation and Guidelines

Des

C

O

Dec

 

S3.7.1

Implementation of the Air Pollution Control (Construction Dust) Regulation and good site practices:

·        Use of regular watering to reduce dust emissions from exposed site surfaces and unpaved road, with complete coverage, particularly during dry weather;

·        Use of frequent watering for particularly dusty static construction areas and areas close to ASRs;

·        Tarpaulin covering of all dusty vehicle loads transported to, from and between site location;

·        Establishment and use of vehicle wheel and body washing facilities at the exit points of the site;

·        Routing of vehicles and positioning of construction plant should be at the maximum possible distance from ASRs;

·          Stockpiled excavated materials should be covered with tarpaulin, and should be removed off-site within 24 hours to avoid any odour nuisance arising.

Work site / During the construction period

Contractor

 

Ö

 

 

Air Pollution Control (Construction Dust) Regulation

# All recommendations and requirements resulted during the course of EIA/EA Process, including ACE and / or accepted public comment to the proposed project.

* Des - Design, C - Construction, O – Operation, and Dec - Decommissioning

Table 11.2       Implementation Schedule for Construction Noise Control

EIA Ref #

Environmental Protection Measures / Mitigation Measures

Location / Timing

Implementation Agent

Implementation Stages*

Relevant Legislation and Guidelines

Des

C

O

Dec

 

S4.8.1

Good Site Practice

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

·        Silencers or mufflers on construction equipment should be utilized and should be properly maintained during the construction program;

·        Mobile plant, if any, should be sited as far from NSRs as possible;

·        Machines and plant (such as trucks) 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, wherever possible, be orientated so that the noise is directed away from the nearby NSRs; and

·        Material stockpiles and other structures should be effectively utilized, wherever practicable, in screening noise from on-site construction activities.

Work site / During the construction period

Contractor

 

Ö

 

 

ProPECC PN2/93 and Noise Control Ordinance

S4.8.2- S4.8.4

Use of quiet PME

Work site / During the construction period

Contractor

 

Ö

 

 

ProPECC PN2/93 and Noise Control Ordinance

S4.8.5- S4.8.6

Use of movable noise barriers and temporary noise barrier

Work site / During the construction period

Contractor

 

Ö

 

 

ProPECC PN2/93 and Noise Control Ordinance

S4.1011.1

Environmental Monitoring and Audit (EM&A) programme is recommended to be implemented during the construction stage.

Work site / During the construction period

Contractor

 

Ö

 

 

-

# All recommendations and requirements resulted during the course of EIA/EA Process, including ACE and / or accepted public comment to the proposed project.

* Des - Design, C - Construction, O – Operation, and Dec - Decommissioning

Table 11.3       Implementation Schedule for Water Quality Control

EIA Ref #

Environmental Protection Measures / Mitigation Measures

Location / Timing

Implementation Agent

Implementation Stages*

Relevant Legislation and Guidelines

Des

C

O

Dec

S5.307.2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Construction Site Runoff and Drainage

·          Before commencing any site formation work, all sewer and drainage connections shall be sealed to prevent debris, soil, sand etc. from entering public sewers/drains.

·          Temporary ditches shall be provided to facilitate run-off discharge into appropriate watercourses, via a silt retention pond.  No site run-off shall enter the freshwater marshes at Luk Tei Tong.

·          Sand/silt removal facilities such as sand traps, silt traps and sediment basins shall be provided to remove sand/silt particles from runoff to meet the requirements of the Technical Memorandum standard under the Water Pollution Control Ordinance.  The design of silt removal facilities shall be based on the guidelines provided in ProPECC PN 1/94.  All drainage facilities and erosion and sediment control structures shall be inspected monthly and maintained to ensure proper and efficient operation at all times and particularly during rainstorms. 

·          Water pumped out from foundation excavations shall be discharged into silt removal facilities.

·          During rainstorms, exposed slope surfaces shall be covered by a tarpaulin or other means. Other measures that need to be implemented before, during, and after rainstorms are summarized in ProPECC PN 1/94.

·          Exposed soil areas shall be minimized to reduce potential for increased siltation and contamination of runoff. 

·          Exposed soil surfaces shall be protected by paving or fill material as soon as possible to reduce the potential of soil erosion.

·          Open stockpiles of construction materials or construction wastes on-site of more than 50 m3 shall be covered with tarpaulin or similar fabric during rainstorms.

Work site / During the construction period

Contractor

 

Ö

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ProPECC PN 1/94; WPCO

S5.317.3 – S5.327.4

 

 

 

 

 

 

 

 

General Construction Activities

·        Debris and refuse generated on-site shall be collected, handled and disposed of properly to avoid entering the river channels, the Luk Tei Tong freshwater marshes and local storm water drains.  Stockpiles of cement and other construction materials shall be kept covered when not being used. 

 

·        Oils and fuels shall only be used and stored in designated areas which have pollution prevention facilities.  All fuel tanks and storage areas shall be provided with locks and be sited on sealed areas, within bunds of a capacity equal to 110% of the storage capacity of the largest tank.  The bund shall be drained of rainwater after a rain event.

 

Work site / During the construction period

Contractor

 

Ö

 

 

ProPECC PN 1/94; WPCO

S5.7.533

Sewage from Construction Workforce

Temporary sanitary facilities, such as portable chemical toilets, shall be employed on-site.  A licensed contractor shall be responsible for appropriate disposal and maintenance of these facilities. 

Work site / During the construction period

Contractor

 

Ö

 

 

WPCO

S5.7.634

River Channel Excavation Works

Excavation and widening works for the drainage improvements to the Pak Ngan Heung River, Tai Tei Tong River and Luk Ti Tong River shall be carried out in sections (approximately 300 – 400 m in length) and in dry condition.   Containment measures such as bunds and barriers shall be used within the river channel and the excavation works restricted to within an enclosed dry section of the channel.  The excavation and widening works shall be carried out in the dry season as far as practicable.

 

Work site / During the construction period

Contractor

 

Ö

 

 

 

S5.7.7

Maintenance Desilting of River Channels

For maintenance desilting of the re-profiled river channels of Pak Ngan Heung River, Tai Tei Tong River and Luk Ti Tong River, temporary barrier walls shall be used to provide a dry work zone for desilting work.  Maintenance desilting shall be carried out during periods of low flow in the dry season.

Work site / During the operation period

Contractor

 

 

Ö

 

 

S.5.9.1

During construction phases, monitoring of downstream water quality within the rivers should be undertaken, together with regular site audits.

With the rivers /

During the construction period

Contractor

 

Ö

 

 

 

# All recommendations and requirements resulted during the course of EIA/EA Process, including ACE and / or accepted public comment to the proposed project.

* Des - Design, C - Construction, O – Operation, and Dec - Decommissioning

Table 11.4       Implementation Schedule for Waste Management Implications

EIA Ref #

Environmental Protection Measures/Mitigation Measures

Location/ Timing

Implementation Agent

Implementation Stages*

Relevant Legislation and Guidelines

Des

C

O

Dec

S6.5.2 – S6.5.3

Good Site Practices

 

Good site practices during the construction activities include:

·         Nomination of approved personnel, such as a site manager, to be responsible for good site practices and making arrangements for collection of all wastes generated at the site and effective disposal to an appropriate facility.

·         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 (including the disposal sites) shall be proposed.

·         A Waste Management Plan shall be prepared and submitted to the Engineer for approval. One may make reference to ETWB TCW No. 15/2003 for details.

·         In order to monitor the disposal of C&D materials at landfills and public filling areas, and to control fly tipping, a trip-ticket system shall be included as one of the contractual requirements. One may make reference to WBTC No. 21/2002 for details.

 

Work site / During the construction period

Contractor

 

Ö

 

 

Waste Disposal Ordinance (Cap.54)

WBTC No.21/2002, ETWB TCW No. 15/2003

S6.5.4

Waste Reduction Measures

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 materials and their proper disposal.

·        Separate labelled bins shall be provided to segregate aluminium cans from other general refuse generated by the workforce, and to encourage collection of by individual collectors.

·         Any unused chemicals or those with remaining functional capacity shall be recycled.

·         Maximising the use of reusable steel formwork to reduce the amount of C&D material.

·         Prior to disposal of C&D waste, it is recommended that wood, steel and other metals shall be separated for re-use and / or recycling to minimise the quantity of waste to be disposed of to landfill.

·         Proper storage and site practices to minimise the potential for damage or contamination of construction materials.

·         Plan and stock construction materials carefully to minimise amount of waste generated and avoid unnecessary generation of waste.

·         Minimize over ordering of concrete, mortars and cement grout by doing careful check before ordering.

 

Work site / During planning & design stage, and construction stage

Contractor

Ö

Ö

 

 

WBTC No.4/98, ETWB TCW No. 15/2003

S6.5.6 – S6.5.8

Construction & Demolition (C&D) Material

C&D material generated from the river improvement works with suitable characteristics shall be reused on-site as fill material as far as practicable, such as for backfilling of box culverts and drainage pipes, and small cobbles and rocks shall be used in the construction of the recreated channel bed. 

When disposing C&D material at a public filling area, it shall be noted that the material shall only consist of soil, rock, concrete, brick, cement plaster/mortar, inert building debris, aggregates and asphalt.  The material shall be free from marine mud, household refuse, plastic, metals, industrial and chemical waste, animal and vegetable matter, and other material considered to be unsuitable by the Filling Supervisor.

C&D material generated from demolition of existing structures and river crossings shall be sorted on-site into public fill and C&D waste.  Suitable areas shall be designated within the works site boundaries for temporary stockpiling of C&D material.  Within stockpile areas, the following measures shall be taken to control potential environmental impacts or nuisance:

·         covering material during heavy rainfall;

·         locating stockpiles to minimse potential visual impacts; and

·         minimizing land intake of stockpile areas as far as possible.

Work site / During the construction period

Contractor

 

Ö

 

 

WBTC No. 4/98, 21/2002, 25/99, 12/2000

ETWB TCW No. 15/2003, 33/2002

S6.5.9

Excavated Riverbed Material

Use of water-tight trucks for the transportation of excavated riverbed material to the designated barging point for disposal at the designated public filling area, or transported directly to the public filling area. 

Work site / During the construction period

Contractor

 

 

 

Ö

 

 

 

 

 

S6.5.10

Chemical Waste

If chemical wastes are produced at the construction site, the Contractor shall register with the EPD as a Chemical Waste Producer and follow the guidelines stated in the Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes. Good quality containers compatible with the chemical wastes shall be used, and incompatible chemicals shall be stored separately.  Appropriate labels shall be securely attached on each chemical waste container indicating the corresponding chemical characteristics of the chemical waste, such as explosives, flammable, oxidizing, irritant, toxic, harmful, corrosive, etc.  The Contractor shall use a licensed collector to transport and dispose of the chemical wastes generated at the Chemical Waste Treatment Centre at Tsing Yi, or other licenced facility, in accordance with the Waste Disposal (Chemical Waste) (General) Regulation.

Work site / During the construction period

Contractor

 

Ö

 

 

Waste Disposal (Chemical Waste) (General) Regulation

S6.5.11

General Refuse

General refuse shall be stored in enclosed bins or compaction units separate from C&D material.  A reputable waste collector shall be employed by the contractor to remove general refuse from the site, separately from C&D material.  An enclosed and covered area is preferred to reduce the occurrence of 'wind blown' light material.

Work site / During the construction period

Contractor

 

Ö

 

 

Public Health and Municipal Services Ordinance (Cap. 132)

# All recommendations and requirements resulted during the course of EIA Process, including ACE and / or accepted public comment to the proposed project.

·          Des - Design, C - Construction, O - Operation and Dec – Decommissioning

Table 11.5       Implementation Schedule for Ecological Requirements

EIA Ref #

Environmental Protection Measures / Mitigation Measures

Location / Timing

Implementation Agent

Implementation Stages*

Relevant Legislation and Guidelines

Des

C

O

Dec

 

S7.7.1- S7.7.27.

 

S7.8.3.

 

S7.8.10.

S7.8.2, S7.8.4

S7.8.125-

S7.8.187.

Design of River Channels

 

The scale of impacts to river habitats would be determined largely by the design of drainage channels built to replace existing rivers. Ecological requirements have been considered during the design of drainage improvement works, and are described as follows.

 

Pak Ngan Heung River

Drainage improvements would be implemented by constructing an underground channel that would bypass a sharp bend in the river close to Butterfly Hill. Under normal conditions, flow would be maintained within the existing river channel. During high flow events, excess floodwaters would be conveyed through the by-pass channel.,

Under this design, modification to the existing PNH River would be limited to two short sections upstream and downstream of the proposed Bypass Channel. At the downstream section, the river channel would be slightly widened, with new vertical concrete retaining walls constructed along the banks of the channel. The channel widening would result in some new sections of riverbed being created, which would be lined with natural materials such as small cobbles and boulders. The existing riverbed and substrates would be retained.

The upstream section of PNH River would be widened and slightly re-aligned. The new channel banks would be trapezoidal in cross-section, and lined with rock-filled gabion. Pits would be provided in the gabion bank to allow for planting and establishment of riparian vegetation. The depth of the new channel bed would be varied to re-create the pool-riffle sequence found in the existing River, and a small weir at the upstream end of the existing river currently maintained for crop irrigation would be re-instated. Similar to the downstream section, the newly constructed riverbed would be lined with natural materials such as cobbles and boulders.

 

The newly created PNH River drainage channel is expected to provide a suitable habitat for the fish species of conservation interest (Flagtail, Kuhlia marginata) previously recorded from the river. To further increase the value of the PNH River for this and other fish species, it is recommended that a small fish ladder is constructed at the upstream end of the new channel. The existing agricultural weir at this location currently impedes the movement of fish between upstream and downstream sections of the river. The fish ladder would facilitate movement past this obstacle, extending the range of fish communities in both upstream and downstream areas. The detailed design of the ladder would be finalised at a later stage of this Project.

TTai Tei Tong River

Proposed drainage improvements at TTT River would be limited to the widening of three small bottlenecks along the existing river, with the total length of the river affected by the works reduced by almost half to 160m. . The bottleneck at the downstream end of TTT River (close to the confluence of the three rivers) would be widened along one bank only, with a new concrete retaining wall constructed along this bank. At the two upstream bottlenecks, the newly widened banks would be stabilised with rock-filled gabion.

 
LLuk Tei Tong River

Lower section of the LTT River would be slightly widened and deepened (total length 225m). Ecological enhancement features to be included along the improved river section would include:

 

·                 The channel bed would be constructed using natural materials such as small cobbles and boulders.

 

·                 The depth of the channel would be varied to re-create the pool-riffle sequence found in the existing river.

 

·                 The new channel banks would be trapezoidal in cross-section, and lined with rock-filled gabion. Pits would be provided in the gabion bank to allow for planting and establishment of riparian vegetation.

 

Luk Tei Tong (2) River

The proposed works would largely avoid direct impacts to the river by creating a flood Bypass Channel, with just small sections of the existing river connecting to the upstream and downstream ends of the Bypass Channel affected. Similar to the PNH River, existing flow within the flow LTT (2) River would be maintained under normal conditions, with excess flow diverted to the Bypass Channel during high flow events. Unlike the PNH River Bypass Channel, the LTT (2) River Bypass Channel would be open, not routed underground.

 

General

As the new drainage channels would be approximately the same width as the existing watercourses, it is anticipate that most of the substrates used to line the new channel beds can be taken from the existing rivers. Rocks unearthed during excavation works for this Project or material purchased from local quarries would be used as material to fill gabion bank linings and as additional substrate to line the riverbeds if required.

In time, it is expected that vegetation will naturally re-colonise newly constructed channel sections. To expedite this process, planting of suitable aquatic, emergent and riparian plant species within the beds and gabion-lined sections of channels will be undertaken following the completion of works (Table 2.7 lists some suggested species for use in this planting). Additionally, the gabion lining will be hydroseeded. Planting design will be finalised in the detailed design stage.

The newly created PNH River drainage channel is expected to provide a suitable habitat for the fish species of conservation interest (Flagtail, Kuhlia marginata) previously recorded from the river. To further increase the value of the PNH River for this and other fish species, it is recommended that a small fish ladder is constructed at the upstream end of the new channel. The existing agricultural weir at this location currently impedes the movement of fish between upstream and downstream sections of the river. The fish ladder would facilitate movement past this obstacle, extending the range of fish communities in both upstream and downstream areas. A conceptual layout of the proposed fish ladder is given in Figure 7.3, showing a basic design of rock-ramp fishway commonly adopted in Australia and other countries to facilitate the passage of various fish species over low obstructions. The detailed design of the ladder would be finalised at a later stage of this Project.

 

As the new drainage channels would be approximately the same width as the existing watercourses, it is anticipate that most of the substrates used to line the new channel beds can be taken from the existing rivers. Rocks unearthed during excavation works for this Project or material purchased from local quarries would be used as material to fill gabion bank linings and as additional substrates to line the riverbeds if required.

The primary potential ecological impact resulting from the Project would be the loss of small sections of lowland river habitat. The scale of this impact would be determined largely by the design of drainage channels built to replace existing rivers. Ecological requirements have been considered during the design of the channels, with the following key features included in channel design for PNH, TTT and LTT Rivers:

·Channel beds would be constructed using natural materials such as small cobbles and boulders. Where possible, construction would utilise suitably sized cobbles/boulders found in the existing rivers. This recreated habitat would provide a suitable environment for many organisms dependent on the existing watercourses.

·Channel banks would be largely trapezoidal, and lined with grasscrete.

·The depth of the channels would be varied to re-create the pool-riffle sequence found in natural streams.

·Larger pools in the stream and river currently maintained for crop irrigation would be re-instated.

 

The proposed design of the channel that would replace the small LTT (2) River has been considered to minimise and compensate for anticipated impacts to the existing stream and also the surrounding Luk Tei Tong Marsh. The following key features would be included in the LTT (2) River Channel design:

·A low-flow channel of similar width to the existing LTT (2) River would be included in the new channel. The bed of the low-flow channel would be lined with natural materials. The banks of the low-flow channel would be reinforced with rock-filled gabion.

·The remainder of the LTT (2) channel bed would be reinforced with geo-textile matting. The matting would be overlain with turf taken from adjacent areas of Luk Tei Tong Marsh that would be directly affected by the proposed works. This area would be maintained as compensatory marshland habitat.

· The banks of the whole proposed Channel would be lined with rock-filled gabion.

 

To minimise impacts to LTT Marsh, no the footpath/access road should be constructed along the LTT (2) River Channel.

 

River channels during design/construction phase.

Project Proponent/ Contractor.

Ö

Ö

 

 

-

S7.8.23.

 

 

Avoidance of Disturbance to White-shouldered StarlingBreeding Fauna

 

The works programme has been considered to avoid impacts to breeding wildlife where possible. Works within Luk Tei Tong Marsh and the confluence of the three rivers would be restricted to the dry season, thereby avoiding impacts to White-shouldered Starlings (Sternus sinensis) that have been recorded breeding in the Disused Watchtowers close to the river confluence, and also to other avifauna and herpetofauna species that may breed within Luk Tei Tong Marsh.Works close to the disused Watchtowers (at the river outlets) should be conducted in the dry season only (November-March). This would avoid the main breeding season of the Starling, which is in the wet season (generally starting in May).

River outlets during construction phase.

Contractor.

 

Ö

 

 

-

S7.8.5

Minimise Sedimentation

 

 

All excavation works carried out within or close to water bodies should be carried out in the dry season where possible, with construction carried out by land-based plant. Excavation works within river/stream channels should be restricted to an enclosed dry section of the river, with containment measures such as bunds and barriers used within the river to minimize the impacts upon the downstream water body. Site runoff should be directed towards regularly cleaned and maintained silt traps and oil/grease separators to minimise the risk of sedimentation and pollution of river water. The silt and oil/grease separators should be appropriately designed for the local drainage and ground conditions. To minimize leakage and loss of sediments during excavation in narrow channels, tightly sealed closed grab excavators should be deployed where material to be handled is wet.

Works areas during construction phase.

Contractor.

 

Ö

 

 

-

S7.8.6

Minimise Noise Impacts

 

Noise mitigation measures including the use of quiet construction plant and temporary noise barriers should be implemented to minimise disturbance to habitats adjacent to the works areas.

Works areas during construction phase.

Contractor.

 

Ö

 

 

-

S7.8.7

General Site Practice

 

Standard good site practice measures should be implemented throughout the construction phase. The measures should include:

·         Placement of equipment or stockpile in designated works areas and access routes selected on existing disturbed land to minimise disturbance to natural habitats and vegetation, particularly mature trees.

·         Construction activities should be restricted to work areas that should be clearly demarcated. The work areas should be reinstated after completion of the works.

·         Waste skips should be provided to collect general refuse and construction wastes. The wastes should be disposed of timely and properly off-site.

·         General drainage arrangements should include sediment and oil traps to collect and control construction site run-off.

·         Open burning on works sites is illegal, and should be strictly prohibited.

Works areas during construction phase.

Contractor.

 

Ö

 

 

-

S7.8.8

Minimise Operation Phase Disturbance Impacts

The following measures are recommended to minimise potential impacts resulting from operational phase activities:

·         To minimise sedimentation, de-silting should be limited to the dry season (November-March).

·         For maintenance desilting of the re-profiled river channels, temporary barrier walls shall be used to provide a dry zone for desilting work.

·         The implementation of de-silting and other activities that could disturb aquatic fauna should be phased to ensure some areas of relatively undisturbed habitat remain available for resident aquatic fauna at all times.

·         Waste material produced during de-silting should be disposed of in a timely and appropriate manner.

River Channels during operation phase.

Maintenance Agent.

 

 

Ö

 

-

S7.8.9- S7.8.11

 

S7.8.189-

S7.8.1923

Luk Tei Tong (2) River Bypass Channel

 

To minimise impacts to Luk Tei Tong Marsh, No footpath would be constructed along the bypass channel.

 

Construction of the Bypass Channel would be limited to one dry season only, thereby minimising disturbance impacts to wetland fauna potentially breeding in the Marsh Area.

 

Operation phase impacts resulting from desilting works within the LTT (2) Bypass Channel are expected to be very minor in scale, given that water flow (and therefore sediment deposition) within the channel would be minimal for much of the year, except during spate events. Vegetation control would be required 1-2 times per year at most to prevent the excessive growth of (especially woody) vegetation that would impede the drainage capacity of the channel. These measures do not necessarily conflict with the maintenance of the channel as marshland, as the removal and control of vegetation would be required anyway to maintain the sub-climatic vegetation community found in marsh habitats. It is recognised, however, that regular cutting of vegetation could prevent the re-establishment of wetland communities, with potential disturbance to breeding fauna of particular concern. It is therefore recommended that vegetation control is undertaken outside of the main breeding season for wildlife (April-August) to avoid potential impacts.

The following key features would be included in the Channel design:

 

·         The Bypass Channel bed would be approximately 800mm below the existing ground level, and would be lined with turf taken from areas of Luk Tei Tong Marsh that fall within the footprint of the proposed Channel. This area would be maintained as compensatory marshland habitat. So as to maintain the flood protection function of the channel, vegetation within the Channel would be maintained at a height of about 300mm.

 

·         A low weir would be constructed at the downstream end of the Bypass Channel, serving to retain rainwater and some diverted floodwaters in the Channel. As the channel would be slightly lower than the existing ground level, and water within the channel would be retained, it is anticipated that habitats within the channel provide a more valuable wetland habitat than adjacent areas of Luk Tei Tong Marsh, where wetland vegetation is not particularly well established.

 

·         The banks of the proposed Channel would be lined with rock-filled gabion, and topped with small (200mm high) earth bund. The gabion lining is required to stabilize the banks of the Channel, and the earth-bund would prevent surface water from surrounding areas of the marsh from draining into the Channel.

The intention of re-using turf from the channel alignment is to provide suitable soil conditions for wetland habitats within the Bypass Channel. Additionally, roots and seeds of some plant species within the turf would speed up the establishment of wetland vegetation within the Channel. It should be noted though that parts of the Channel alignment are currently dominated by the weed Mikania micrantha, which would require removal prior to the construction phase. Reference should be made to Nature Conservation Practice Note No. 01/2003.

The construction of the LTT(2)  bBy-pass cChannel is expected to take approximately 5 months. There is some concern that during this period, vegetation in sods of turf removed from the channel alignment would suffer some die-back before being replaced within the channel. To minimize potential die-back, it is recommended that turf removal (and channel construction) is limited to sections no more than 100m in length. The construction sequence would involve excavating the first 100m of the channel (at the downstream end of the alignment). Turf from this section would be moved to a temporary storage area. To minimize potential damage to this vegetation, the turf would not be stacked in layers during storage, and would be adequately watered for the duration of the storage period (i.e., 1-2 times daily). Following removal of the first 100m of turf, the second 100m of the channel would be excavated, and turf from this section immediately installed in the first excavated section of the channel. This process would be repeated until the last section of the channel is excavated. Turf removed from the first 100m section and stored during the construction would be used to re-vegetate this area. Even if some die-back occurs, it is expected that the roots and seed-bank within the turf will provide adequate material for the re-generation of vegetation following re-introduction into the LTT (2) Bypass Channel. Furthermore, vegetation from adjacent areas of the marsh would also be expected to re-colonise substrates within the Channel, which would provide a suitable growing medium for vegetation recorded from the marsh area. A programme would be established to monitor the ecology (including vegetation communities) of the LTT (2) By-pass Channel during the operation phase. If there appears to be any problem with vegetative re-establishment, remedial measures (including the planting of riparian/emergent /aquatic vegetation) would be implemented.

The new wetland area within the Bypass Channel would cover an area of approximately 0.6ha. Although this would be slightly smaller than the 0.8ha of existing habitat affected by the improvement works, wetlands provided within the channel alignment would be of higher ecological value than the habitats they would replace, providing adequate compensation for habitat loss.

  

Temporary works areas adjacent to the Bypass Channel alignment would be re-instated with the planting of appropriate wetland plant species following the completion of construction works. No long-term impact to these areas are expected.

The Bypass Channel bed would be approximately 800mm below the existing ground level, and would be lined with turf taken from areas of Luk Tei Tong Marsh that fall within the footprint of the proposed Channel. This area would be maintained as compensatory marshland habitat.

 

A low weir would be constructed at the downstream end of the Bypass Channel, serving to retain rainwater and some diverted floodwaters in the Channel. As the channel would be slightly lower than the existing ground level, and water within the channel would be retained, it is anticipated that habitats within the channel provide a more valuable wetland habitat than adjacent areas of Luk Tei Tong Marsh, where wetland vegetation is not particularly well established.

 

The banks of the proposed Channel would be lined with rock-filled gabion, and topped with small (200mm high) earth bund. The gabion lining is required to stabilize the banks of the Channel, and the earth-bund would prevent surface water from surrounding areas of the marsh from draining into the Channel.

LTT (2) Bypass Channel

Project Proponent, Contractor, Maintenance Agent

Ö

Ö

Ö

 

-

S7.8.4102

Minimise Impacts to Trees by Ling Tsui Tau U-Channel

 

To minimise impacts to woodland habitats, the alignment of the proposed U-Channel should avoid nearby mature trees as far as practicable.

Ling Tsui Tau U-Channel during design/construction phase.

Project Proponent/ Contractor.

Ö

Ö

 

 

-

S7.8.5113-

S7.8.14

Capture-Surveys of Fish and Amphibian Species of Conservation Interest

Proposed works at the rivers have the potential to impact fish species of conservation interest. To minimize these potential impacts, it is recommended that capture-surveys of the proposed works areas are conducted prior to the commencement of construction works in the channel. These surveys should include fish species of conservation interest recorded during the surveys (Flagtail, Kuhlia marginata & Predaceous Chub, Parazacco spilurus), with particular attention paid to the Flagtail. Either of these species caught during the surveys should be re-located to areas of the watercourse upstream of the proposed works areas, or to aquaria set up close to the works areas. Maintenance of the fish prior to translocation would be undertaken by an ecologist appointed by the Project Proponent. The capture surveys should be conducted in the dry season by a suitably qualified ecologist(s) appointed by the Project Proponent. For the Flagtail (which will probably occur in low densities at PNH River), further surveys should be conducted to confirm the presence and numbers of fish in the streams closer to the time of construction. A detailed methodology for fish translocation (based in part upon the Flagtail survey results) should be formulated during the detailed design stage of the Project.

In addition to fish species of conservation interest, the proposed drainage improvement works could also result in direct impacts to two amphibian species of conservation interest, RTF and Chinese Bullfrog. It is therefore recommended that additional capture surveys are conducted prior to the commencement of works to locate any individuals of these two species within the works areas. The surveys should be conducted in the wet season (March/April-October), when these species are calling and are generally more conspicuous. Any individuals captured during the survey should be relocated to similar nearby habitats outside of the works areas. The capture surveys should be conducted by a suitably qualified ecologist(s) appointed by the Project Proponent. A detailed methodology for faunal translocation should be formulated during the detailed design stage of the Project.Proposed works at the rivers have the potential to impact fish species of conservation interest. To minimize these potential impacts, it is recommended that capture-surveys of the proposed works areas are conducted prior to the commencement of construction works in the channel. These surveys should include all three fish species of conservation interest recorded during the surveys (Flagtail, Kuhlia marginata; Predaceous Chub, Parazacco spilurus & Half-banded Barb, Capoeta semifasciolata), with particular attention paid to the Flagtail. It is recommended that capture surveys are conducted using a variety of techniques, including electro-fishing. Electro-fishing would maximize the probability that any fish species of conservation interest inhabiting the rivers would be successfully captured and translocated.

Any of these species caught during the surveys should be re-located to areas of the watercourse upstream of the proposed works areas, or to aquaria set up close to the works areas. Maintenance of the fish prior to translocation would be undertaken by an ecologist appointed by the Project Proponent. The capture surveys should be conducted in the dry season by a suitably qualified ecologist(s) appointed by the Project Proponent. A detailed methodology for faunal translocation should be formulated during the detailed design stage of the Project.

In the event that no fish are caught, it is suggested that re-stocking the newly constructed drainage channels is considered. Possible sources of fish for re-stocking would include captive populations and wild populations from nearby rivers.

 

In addition to fish species of conservation interest, the proposed drainage improvement works could also result in direct impacts to two amphibian species of conservation interest, RTF and Chinese Bullfrog. It is therefore recommended that additional capture surveys are conducted prior to the commencement of works to locate any individuals of these two species within the works areas. The surveys should be conducted in the wet season (March/April-October), when these species are calling and are generally more conspicuous. Any individuals captured during the survey should be relocated to similar nearby habitats outside of the works areas. The capture surveys should be conducted in the dry season by a suitably qualified ecologist(s) appointed by the Project Proponent. A detailed methodology for faunal translocation should be formulated during the detailed design stage of the Project.The proposed works have the potential to impact fish species of conservation interest. To minimize these potential impacts, it is recommended that capture-surveys of the proposed works areas are conducted prior to the commencement of construction works in the channel in the dry season. These surveys should include all three fish species of conservation interest recorded during the surveys (Flagtail, Kuhlia marginata; Predaceous Chub, Parazacco spilurus & Half-banded Barb, Capoeta semifasciolata), with particular attention paid to the Flagtail. Any of these species caught during the surveys should be re-located to areas of the watercourse upstream of the proposed works areas, or in aquaria set up close to the works areas. The capture surveys should be conducted by a suitably qualified ecologist(s) appointed by the Project Proponent. A detailed methodology for faunal translocation should be formulated during the detailed design stage of the Project.

River channelsWorks areas  prior to construction activities. Maintenance throughout construction phase.

Ecologist.

 appointed by the Project Proponent.

Ö

Ö

Ö

 

-

S7.8.7

Minimise Noise Impacts

Noise mitigation measures including the use of quiet construction plant and temporary noise barriers should be implemented to minimise disturbance to habitats adjacent to the works areas.

Works areas during construction phase.

Contractor.

 

Ö

 

 

-

S7.8.13204

Compensatory Tree and Shrub Planting

Planting of trees and other vegetation along the banks of the newly created channels would provide compensation for unavoidable tree-felling and loss of small areas of open and secondary woodland habitat resulting from the proposed TTT and PNH River Channel and Ling Tsui Tau U-Channel works. Compensatory planting would make use of native plant species with flowers/fruits attractive to wildlife. Compensation in terms of woodland area and trees planted would be on at least a 1:1 ratio, covering an area of at least 0.13ha.Planting of trees and other vegetation along the banks of the newly created channels would provide compensation for unavoidable tree-felling and loss of small areas of secondary woodland habitat resulting from the proposed Pak Ngan Heung River Channel and Ling Tsui Tau U-Channel. Compensatory planting would make use of native plant species with flowers/fruits attractive to wildlife.Planting of trees and other vegetation along the banks of the newly created channels would provide compensation for unavoidable tree-felling and loss of small areas of secondary woodland habitat resulting from the proposed PNH River Channel and Ling Tsui Tau U-Channel. Compensatory planting would make use of native plant species with flowers/fruits attractive to wildlife.

Detailed landscape design during design phase, planting during construction phase.

Designer/Contractor.

Ö

Ö

 

 

-

S7.10.1- S7.10.73

Environmental Monitoring & Audit

The proper implementation of recommended ecological mitigation measures should be audited.

 

A specific monitoring programme of improved sections of PNH and LTT Rivers is recommended. The programme should provide data on the re-establishment of aquatic/riparian communities in the channels, and allow an assessment of the relative success of mitigation measures to be made. Baseline data should be collected several months before the commencement of the construction phase, with monitoring conducted on a monthly basis during the construction phase, and every two months a year for 4 years after the completion of works. Data collected should include the following parameters:A specific monitoring programme of improved sections of PNH and LTT Rivers is recommended. The programme should provide data on the re-establishment of aquatic/riparian communities in the channels, and allow an assessment of the relative success of mitigation measures to be made. Baseline data should be collected several months before the commencement of the construction phase, with monitoring conducted on a monthly basis year during the construction phase, and every two months a year for 4 years after the completion of works. Data collected should include the following parameters:

§                 Water quality (e.g., dissolved oxygen, pH, conductivity, salinity, BOD, nutrient concentrations);

§                 Sediment characteristics;

§                 Water flow;

§                 Avifauna species and densities;

§                 Aquatic macroinvertebrate communitiesy species composition and abundance;

§                 Fish communitiesy species composition and abundance;

§                 Adult odonate communitiesy species composition and abundance;

§                 Aquatic, emergent and riparian vegetation communitiesy species composition and abundance.

Reports on the findings of each monitoring trip should be submitted to Agriculture, Fisheries and Conservation Department (AFCD) for review. A final report summarising the monitoring results over the entire monitoring period should be prepared to serve as a reference for future projects of this kind. Monitoring should be conducted by a qualified ecologist(s) with over 6 years relevant experience appointed by the Project Proponent.

 

Monitoring of the LTT (2) Bypass Channel would be required to confirm that the proposed Channel design has provided suitable compensation for impacts to Luk Tei Tong Marsh. It is suggested that ecological monitoring of habitats within the Channel should be undertaken for a period of at least 4 years. Data collected should include the following key parameters:

§                 Water quality (e.g., dissolved oxygen, pH, conductivity, salinity, BOD, nutrient concentrations);

§                 Sediment characteristics;

§                 Water depth and flow;

§                 Avifauna species and densities;

§                Aquatic macroinvertebrate community species composition and abundance;

§                 Fish community species composition and abundance;

§                 Herpetofauna community species composition and abundance;

§                 Adult odonate community species composition and abundance;

§                 Aquatic, emergent and riparian vegetation community species composition and abundance.Aquatic macroinvertebrate communities;

§                 Fish communities;

§                 Herpetofauna communities;

§                 Adult odonate communities;

§                 Aquatic, emergent and riparian vegetation communities.

To provide baseline data, it is suggested that the same parameters are measured along a strip of existing marsh habitat adjacent to the Channel alignment. A comparison of species diversity and densities along the Bypass Channel alignment and at the reference site would allow the effectiveness of habitat creation to be assessed. Monitoring of both the Channel and Reference Site should be conducted 6 times a year for 4 years after the completion of works. Reports on the findings of each monitoring trip should be submitted to AFCD for review. A final report summarising the results of monitoring over 4 years should be prepared to serve as a reference for future projects of this kind. Monitoring should be conducted by a qualified ecologist(s) with over 6 years relevant experience appointed by the Project Proponent.

 

The newly constructed PNH and LTT River Channels, and LTT (2) Bypass Channel are expected to provide a similar habitat to the habitats they would replace. It is therefore anticipated that wildlife found in the existing rivers and marsh would successfully re-colonise the new channels. However, if the post-construction phase monitoring demonstrates that re-colonisation is unsuccessful the following contingency plan should be implemented:

 

·         Baseline/reference data should be compared with post-construction phase data. Any substantial differences in habitat characteristics (e.g., water quality, aquatic/emergent vegetation) should be noted.

 

·         The potential cause of differences between baseline/reference and post-construction phase habitat characteristics (e.g., changes in water depth, sediment characteristics) should be identified.

 

·         Measures to further rehabilitate the habitat characteristics of the channels should be implemented. Such measures could include:

-         Minor re-profiling of the channel bed(s) could be implemented to increase micro-habitat diversity within the channels. By excavating small areas of the bed, areas of slow flowing water would be created within river habitats, and small pools of very slow-flowing or standing water would be created within the marsh.

-         Increasing heterogeneity of substratum would again increase micro-habitat diversity: providing substrates of different sizes would provide niches for organisms preferring small sediments (e.g., burrowing dragonfly larvae) and larger cobbles/boulders (e.g., Heptageniid mayfly nymphs).

-         Planting of suitable aquatic, emergent and riparian vegetation could serve to increase vegetative cover.

-         Management of water levels within the LTT (2) River Bypass Channel could be implemented by modifying the height of the weirs at either end of the Channel; thus optimizing conditions for wetland habitat establishment within the Channel.Measures to further rehabilitate the habitat characteristics of the channels should be implemented (e.g., minor re-profiling of channel bed, planting of riparian/emergent/aquatic vegetation, increasing heterogeneity of substratum).

 

·         Further monitoring of abiotic and biotic parameters should be conducted to determine the relative success of the contingency habitat rehabilitation measures.

 

A specific monitoring programme for the White-shouldered Starlings is recommended. A qualified ecologist with over 6 years relevant experience  appointed by the Project Proponent should conduct the monitoring. Monthly baseline surveys of the Disused Watchtowers should be undertaken in the wet season prior to the commencement of construction phase activities. The aim of baseline surveys should be to establish whether or not any breeding Starlings are still present. If breeding activities are identified, the number of breeding pairs, the success of breeding and responses to any disturbance should be recorded. During the construction phase, monthly surveys of the Watchtowers are recommended. Information should be collected on behaviour, breeding activity, and any response to disturbance. The source of any disturbance impacts should be identified.

 

 

A specific monitoring programme of channels constructed to replace the existing rivers is recommended. The programme should provide data on the re-establishment of aquatic/riparian and marsh communities in the channels, and allow an assessment of the relative success of mitigation measures to be made. Baseline data should be collected several months before the commencement of the construction phase, with monitoring conducted 4 times a year during the construction phase, and 4 times a year for 3 years after the completion of works. Data collected should include abiotic (e.g., water quality, sediment characteristics) and biotic (e.g., avifauna, macroinvertebrate and fish populations, aquatic, emergent and riparian vegetation) parameters. Reports on the findings of each monitoring trip should be submitted to AFCD for review/discussion. A final report summarising the results of monitoring over 3 years should be prepared to serve as a reference for future projects of this kind. Monitoring should be conducted by a suitably qualified ecologist(s) with over 3 years local experience.

 

A specific EM&A Programme to monitor White-shouldered Starling breeding activity and minimise potential impacts is recommended. A suitably qualified ecologist with over 3 years local experience should conduct the monitoring. Monthly baseline surveys of the disused watchtowers should be undertaken in the wet season (from March to October) prior to the commencement of construction phase activities. The aim of baseline surveys should be to establish whether or not the breeding colony is still present. If breeding activities are identified, the number of breeding pairs, the success of breeding and responses to any disturbance should be recorded. If breeding activities are identified during baseline surveys, monitoring should be continued throughout the construction phase (no monitoring is required if no breeding activity is recorded). Twice monthly monitoring of the watchtowers from March to October is recommended. Information should be collected on behaviour, breeding activity, and any response to disturbance. The source of any disturbance impacts should be identified.

Prior to and during Construction Phase. Operation Phase.

EM Team and Ecologist(s) appointed by the Project Proponent.

Ö

Ö

Ö

 

-

# All recommendations and requirements resulted during the course of EIA/EA Process, including ACE and / or accepted public comment to the proposed project.

* Des - Design, C - Construction, O – Operation, and Dec - Decommissioning

Table 11.6       Implementation Schedule for Cultural Heritage

 

EIA Ref #

Environmental Protection Measures / Mitigation Measures

Location / Timing

Implementation Agent

Implementation Stages*

Relevant Legislation and Guidelines

Des

C

O

Dec

 

S86.6.1- S86.6.3

Archaeology

 

Further archaeological investigation is recommended for the two areas within the Chung Hau Archaeological Sites, including Area E and the site of the abandoned factory, as well as the works area not covered by the previous survey.

 

The construction of the proposed U-channel at Ling Tsui Tau Village should minimise any excavation works within the boundary of the Chung Hau Archaeological Site. Subject to the findings of the further investigation, a watching brief is recommended for any excavation works undertaken by a qualified archaeologist approved by AMO in order to record and collect any artefacts and/or archaeological data during excavation. If significant archaeological deposits are found, a rescue excavation may need to be undertaken. Rescue excavation should be considered as the last resort.

 

Built Heritage

 

Specific construction method should be selected to avoid vibration impact on the retaining wall and buildings of the Yuen Compound during construction of the proposed retaining wall and rubble seawall. Monitoring of vibration impacts should be conducted during the construction works to ensure no damage to the existing structures of the Compound.

Work site/During construction phase

Contractor

 

Ö

 

 

-

# All recommendations and requirements resulted during the course of EIA/EA Process, including ACE and / or accepted public comment to the proposed project.

* Des - Design, C - Construction, O – Operation, and Dec - Decommissioning