EIA Ref

EM&A Ref

No.

Recommended Mitigation Measures

Objectives of the Recommended Measures & Main Concerns to Address

Who to implement the measure

Location of the measure

When to implement the measure?

Implementation Status

 

 

A

Water Quality

 

 

 

 

 

3.8

2.9

 

Use of Silt Screens

Minimize the effect of potential increase in SS levels at the seawater intakes

Contractor

WSD8, WSD9

and EMSD1

Construction

Phase

 

A1

Silt Screens shall be installed at the flushing water intakes WSRs

WSD1, WSD8, WSD9 and EMSD1 to minimise the effect of

potential increase in SS levels at the seawater intakes.

Implemented

3.8

2.9

 

Use of Silt Curtains

Minimize the release of suspended soil from the dredging area

Contractor

Construction

Work Sites

Construction

Phase

 

A2

To minimize the potential SS impact from dredging, deployment of silt curtains around the grab dredgers is recommended; and

 

Before commencement of dredging works, the holder of the Environmental Permit shall submit detailed proposal of the design and arrangement of the frame type silt curtain to EPD for approval.

Implemented

3.10

2.9

A3

Water Quality Monitoring Program

Perform water quality monitoring at sensitive receivers during construction phase

ET

Monitoring Locations as stated in Table 2.1 of the EM&A Manual

Construction Phase

 

 

Water quality monitoring shall be carried out in accordance with Section 2 of the Environmental Monitoring and Audit (EM&A) Manual.

 

Event and Action Plan (EAP) for water quality shall be followed in case of any exceedance in action and limit level.

Implemented

3.8

(EP Ref 3)

-

 

Dredging Operation

Minimize potential adverse effect as a result of dredging activities

Contractor

Construction Work Sites

Construction Phase

 

A4

Only two types of dredgers are allowed for this Project: (a) grab dredger with closed grab, and (b) cutter suction dredger spud pole grab dredger.

Implemented

A5

The speed of any construction vessels shall not exceed 10 knots when passing through the area of the Project.

Implemented

A6

No more than three two grab dredgers with closed grab (or one cutter suction dredger with two closed grab dredgers) shall be operated within the Project Area at any one time for the Project.

Implemented

A7

Only one closed grab dredger or one cutter suction dredger shall be operated in Zone 2B and during which no other closed grab dredger shall be allowed in other zones within the Project Area.

NA-no work in such location

 

A8

No more than one grab dredger with closed grab (or one cutter suction dredger) shall be operated within each of the five main zones at any one time for the Project in which the cutter suction dredger shall only be operated in Zones 2 and 4 with maximum dredging rate of 700 m³ in 30 minutes in any given hour (max. 8,400 m³/day, based on a 12-hour operation per day).

Implemented

A9

The maximum dredging rate for closed grab dredger at Rambler Channel – Zones 1 to 2 (subzones Z1A, Z1B, Z2A, Z2B and Z2C) shall follow the Dredging Plan for the Hotspot, as shown in EP-426/2011/A. 

Implemented

A10

The maximum dredging rate for closed grab dredger at Rambler Channel – Zones 3 to 4 (subzones Z3A to Z4B) shall not exceed 1,600 m³ per day during dry season or 3,440 m³ per day during wet season as shown in EP-426/2011/A.

Implemented

A11

The maximum dredging rate for closed grab dredger at Rambler Channel – Zones 5 to 6 (subzones Z5A,  Z5B and Z6A) shall not exceed 4,000 m³ per day during both dry and wet seasons as shown in EP-426/2011/A.

Implemented

 

A12

The maximum dredging rate for closed grab dredger at Rambler Channel – Zones 5 to 8 (subzones Z5C, Z6B, Z6C, Z6D, Z7 and Z8) shall not exceed 4,000 m³ per day during both dry and wet seasons as shown in EP-426/2011/A.

 

Implemented

 

A13

The maximum dredging rate for closed grab dredger at Northern Fairway – Zones 9 to 12  shall not exceed 4,000 m³ per day during both dry and wet seasons as shown in EP-426/2011/A.

Implemented

 

A14

The maximum dredging rate for closed grab dredger at Western Fairway – Zone 13A shall  not exceed 4,000 m³ per day during both dry and wet seasons as shown in EP-426/2011/A.

NA-Dredging works completed

A15

The maximum dredging rate for closed grab dredger at Western Fairway – Zone 13B shall not exceed 4,000 m³ per day during both dry and wet seasons as shown in EP-426/2011/A.

NA-Dredging works completed

A16

The dredging pump of cutter suction dredger shall be operated during cutting to reduce the sediment loss to water body.

NA-no CSD employed

A17

Project dredging works within Zone 1 to 6 (including sub-zones) of the Container Basin shall not be carried out at the same time with Terminal Operator’s maintenance dredging activities.

NA-No Terminal Operator’s maintenance dredging carried out

A18

Cutter suction dredger is only to be deployed for the removal of harder material during daytime only (07:00 to 19:00) in Zone 2 (including subzones) of the Container Basin.

NA-no CSD employed

A19

In case of rainstorm warning in effect during dredging works, the dredged material on barge shall be covered properly before transportation to disposal site.

NA-no rainstorm warning

A20

In case of exceedance of SS and NH3-N at the Tsing Yi WSD flushing intake due to dredging operation is evidenced, the Contractor shall propose mitigation measures not limited to reducing dredging rate. If exceedance persists, the Contractor shall propose not to undertake dredging operation in close proximity to the Tsing Yi flushing water intake during flood tide. The Contractor shall liaise with the ETL, IEC, ER, EPD and WSD for the proposed mitigation measures.

NA-no exceedance due to dredging operation

A21

If further mitigation measures are required due to continuous exceedance of SS and NH3-N, consideration shall then be given to dredge only on the state of the tide which would avoid migration of SS towards the WSD and EMSD intakes.

NA-no exceedance due to dredging operation

A22

Dredging sub-zone Z2B where high NH3-N in sediment is found shall be isolated with dredging works to be carried out towards the end of construction programme.

NA-no work in such location

A23

Administrative control in terms of dredging rate adjustment in controlling the release of contaminants shall be employed as mitigation measures.

Implemented

A24

Field trials shall be carried out to propose the most effective dredging process and rate to control the release of ammoniacal nitrogen and UIA into the water column and achieve compliance at the WSD1 seawater intake (NH3-N) and at the beaches for UIA.
Capital dredging works in dredging sub-zone Z2B (Figure 1.2h refers) should not therefore be carried out until the proposed method and rate are confirmed.  

Implemented

A25

Detailed dredging plan shall be prepared providing details of individual dredging subzones and dredging rate taking into account of the field trial results.

Implemented

3.8

-

 

Other Good Site Practices for Dredging

Minimize potential adverse effect as a result of dredging activities

Contractor

Construction Work Sites

Construction Phase

 

A26

All vessels should be sized so that adequate clearance is maintained between vessels and the seabed in all tide conditions, to ensure that undue turbidity is not generated by turbulence from vessel movement or propeller wash.

Implemented

A27

The speed of all Contractor’s vessels should be controlled within the works area to prevent propeller wash from stirring up the seabed sediments.

Implemented

A28

All barges / dredgers used should be fitted with tight fitting seals to their bottom openings to prevent leakage of material.

Implemented

A29

Construction activities should not cause foam, oil, grease, scum, litter or other objectionable matter to be present on the water within the site or dumping grounds.

Implemented

A30

No overflow of dredged mud should be allowed. Barges or hopper should not be filled to a level that will cause the overflow of materials or polluted water during loading or transportation.

Implemented

 

 

B

Waste Management

 

 

 

 

 

 

 

 

Good Site Practices

Minimize potential adverse effect arising from the handling of dredged material

Contractor

Construction

Work Sites

(General)

Construction

Phase

 

4.5

3.3

B1

Obtain the profile of different sediment categories and careful planning of sediment removal.

Implemented

B2

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

Implemented

B3

Training of site personnel in proper waste management and chemical handling procedures.

Implemented

B4

Provision of sufficient waste disposal points and regular collection of waste.

Implemented

B5

Well planned delivery programme for offsite disposal such that adverse environmental impact from transporting sediment material is not anticipated.

Implemented

B6

Use well maintained PME on site.

Implemented

 

 

 

General Refuse

Minimize the adverse effect arising from the handling of

site general refuse

Contractor

Construction

Work Sites

(General)

Construction

Phase

 

4.5

3.3

B7

General refuse should be stored in enclosed bins. A reputable waste collector should be employed by the contractor to remove general refuse from the site.

Implemented

 

 

 

Chemical Waste

Minimize the adverse effect

arising from the handling of site chemical waste

Contractor

Construction

Work Site

Construction

Phase

 

4.5

3.3

B8

If chemical wastes are produced at the construction site, the Contractor shall be required to register with the EPD as a chemical waste producer and to 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 should 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 explosive, flammable, oxidizing, irritant, toxic, harmful, corrosive, etc. The Contractor shall use a licensed collector to transport and dispose of the chemical wastes, to either the approved Chemical Waste Treatment Centre, or another licensed facility, in accordance with the Waste Disposal (Chemical Waste) (General) Regulation.

Implemented

4.5

3.3

 

Marine Dredged Sediment 

Control of transportation and

disposal of dredged material in a manner to minimize potential impacts on water

quality

Contractor

Construction

Work Site

Construction

Phase

 

B9

Control of transportation and disposal of dredged material in a manner to minimize potential impacts on water quality.

Implemented

B10

Bottom opening of barges will be fitted with tight fitting seals to prevent leakage of material. Excess material shall be cleaned from the decks and exposed fittings of barges and dredgers before the vessel is moved.

Implemented

B11

Monitoring of the barge loading shall be conducted to ensure that loss of material does not take place during transportation. 
Transport barges or vessels shall be equipped with automatic self-monitoring devices as specified by the EPD.

Implemented

B12

Barges or hopper barges shall not be filled to a level that would cause the overflow of materials or sediment laden water during loading or transportation.

Implemented

B13

Sediment Quality Report shall be prepared and submit to EPD under DASO.

Implemented

B14

If disposal of Type 3 sediment is identified, agreement with EPD shall be reached regarding the treatment of sediment before disposal.

NA – no type 3 material disposed

B15

Project works shall not be carried out before obtaining confirmation from MFC on disposal option.

Implemented

B16

Follow strictly all conditions stipulated in the dumping permit.

Implemented

 

 

C

Marine Ecology

Review and assess the potential adverse effect on marine ecology

Contractor 

Construction Work Sites

Construction Phase

 

5.7

4.1

C1

Water quality monitoring results shall be reviewed from time to time to assess if there were any impact to marine ecology due to dredging operation.

Implemented

 

 

D

Fisheries

Review and assess the potential adverse effect on fisheries

Contractor

Construction Work Sites

Construction Phase

 

6.7

5.1

D1

Water quality monitoring results shall be reviewed from time to time to assess if there were any impact to fisheries due to dredging operation.

Implemented

 

 

E

Hazard to Life

 

Contractor 

Construction Work Sites (General)

Construction Phase

 

7.8.2

6.2

E1

Sound communication channel shall be established with the oil companies, Marine Department, and Fire Services Department for effective notification and emergency evacuation in case of accidents.

Implemented

E2

Proper safety and emergency training shall be given to the relevant operation staff at the dredging site. Emergency plans and procedures should be prepared and drills should be performed periodically.

Implemented

 

 

F

Landscape Visual and Glare

Minimize landscape and visual impacts during construction phase

Contractor 

Construction activities’ area

Throughout design, construction phase

 

8.9 Table 8-3 & 8-6

7.2

F1

Visa shields to the lights of dredgers shall be provided.

Implemented

F2

The light source shall not point directly to any VSRs.

Implemented

F3

Lights shall be switched off if they are not in use.

Implemented

 

 

G

Cultural Heritage

Minimize potential marine archaeological impact during dredging activities

Contractor 

Locations of the 20

unidentified

sonar

contacts and

masked areas

During

Construction

works

 

9.5

8

 

Monitoring Brief

 

G1

A monitoring brief shall be conducted during the dredging. It shall only be required during dredging at the locations of the 20 unidentified sonar contacts and masked areas and does not need to cover all of the dredging activities. Dredging staff should be briefed about the possibility of locating archaeological objects and a marine archaeologist shall be available to monitor the dredged spoil and provide advice. If material indicative of archaeological remains is retrieved, the AMO should be contacted as soon as possible.   

NA-no work in such location

 

 

H

Noise

 

 

 

 

 

10.8

9

 

Good Site Practices

Control and minimize the generation of undue noise

nuisance

Contractor

Construction

Work Sites

(Along the

alignment of

dredging

Construction Phase

 

H1

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

Implemented

H2

Machines and plant that may be in intermittent use should be shut down between works periods or should be throttled down to a minimum.

Implemented

H3

Plant known to emit noise strongly in one direction should, wherever possible, be orientated so that the noise is directed away from nearby NSRs.

Implemented

H4

If dredging is to be carried out during restricted hours, work locations close to NSRs shall be avoided.

Implemented

 

 

I

Construction Dust

 

 

 

 

 

11.7

10

 

Dust Control

Good site practice to control dust and odour impact to the nearby sensitive receivers

Contractor

Construction Work Sites (General)

Construction Phase

 

I1

Requirements of the Air Pollution Control (Construction Dust) Regulation, where relevant, shall be adhered to during the construction period.

Implemented

 

Odour

 

Contractor 

Construction Work Sites (General)

Construction Phase

 

I2

To minimize potential odour emissions, if dredged sediment is anticipated to be placed on barge for more than a day the load shall be properly covered as far as practicable to minimise the exposed area and potential odour.

NA-no work in such condition

I3

If dredged sediment is found to be malodorous it shall be removed from site as soon as possible within one hour after the barge being filled up.

NA-no work in such condition