TABLE B1                  IMPLEMENTATION SCHEDULE

EIA Ref.

EM&A Log Ref

Environmental Protection Measures

Location/Duration of Measures/Timing of Completion of Measures

Implementation Agent

Implementation Stage

Relevant Legislation & Guidelines

Des

C

O

Dec

 

Mitigation Measures for both Grab Dredger and TSHD Options

3.11

A1

No dredging should be carried out at Working Zone BCs from February to April.

Location: Working Zone BCs

Timing/Duration: February to April

HEC & Dredging Contractor

 

a

 

 

Wild Animals Protection Ordinance, Marine Parks Ordinance and Marine Parks Regulations,  Animals and Plants Ordinance

3.11

A2

Vessel route between the dredging site and the disposal sites should avoid the Finless Porpoise habitat area and be subject to a maximum speed limit of 10 knots in southern Lamma waters as indicated in Figure B3.

Location: South Lamma

Timing/Duration: During the Project period

HEC & Dredging Contractor

 

a

 

 

Wild Animals Protection Ordinance, Marine Parks Ordinance and Marine Parks Regulations, Animals and Plants Ordinance

5.2

 

A3

The number of dredgers and operation conditions specified in the applicable CNPs should be strictly followed.  In applying for the CNPs, it should be ensured that the number of dredgers and operation conditions are compatible with the recommendations of this EIA.

Location: The Project Area

Timing/Duration: During restricted hours of the Project period

HEC & Dredging Contractor

 

a

 

 

Noise Control Ordinance

2.11.2

A4

The grab dredger option and TSHD option should not be operated concurrently.

Location: The Project Area

Timing/Duration: During the Project period

HEC & Dredging Contractor

 

a

 

 

WQOs for Southern and Western Buffer WCZs, WPCO, Noise Control Ordinance


 

EIA Ref.

EM&A Log Ref

Environmental Protection Measures

Location/Duration of Measures/Timing of Completion of Measures

Implementation Agent

Implementation Stage

Relevant Legislation & Guidelines

Des

C

O

Dec

 

Mitigation Measures for TSHD Option Only

2.11.4

B1

Dredging works should be carried out in phases in accordance with the programme, number of dredgers and maximum dredging rates specified in Table B4.

Location: The Project Area

Timing/Duration: During dredging

HEC & Dredging Contractor

 

a

 

 

WQOs for Southern and Western Buffer WCZs, WPCO

2.11

 

B2

There should not be more than one TSHD operating concurrently at any time.

Location: The Project Area

Timing/Duration: During dredging

HEC & Dredging Contractor

 

a

 

 

WQOs for Southern and Western Buffer WCZs, WPCO

Mitigation Measures for Grab Dredger Option Only

2.11.4

C1

Dredging works should be carried out in phases in accordance with the programme, number of dredgers and maximum dredging rates specified in Table B3.

Location: The Project Area

Timing/Duration: During dredging

HEC & Dredging Contractor

 

a

 

 

WQOs for Southern and Western Buffer WCZs, WPCO, Noise Control Ordinance

2.8.12

C2

Each grab dredger to be deployed should have a grab capacity of no less than 8 m3.

Location: The Project Area

Timing/Duration: During dredging

HEC & Dredging Contractor

 

a

 

 

WQOs for Southern and Western Buffer WCZs, WPCO

2.12

C3

Cage-type silt curtains as illustrated in Figure B1 should be deployed for grab dredgers.   The silt curtains should be properly maintained during the dredging period.

Location: The Project Area

Timing/Duration: During dredging

HEC & Dredging Contractor

 

a

 

 

WQOs for Southern and Western Buffer WCZs, WPCO

2.11

C4

There should be no more than 5 grab dredgers operating concurrently at any time.

Location: The Project Area

Timing/Duration: During dredging

HEC & Dredging Contractor

 

a

 

 

WQOs for Southern and Western Buffer WCZs, WPCO, Noise Control Ordinance

 


 

EIA Ref.

EM&A Log Ref

Environmental Protection Measures

Location/Duration of Measures/Timing of Completion of Measures

Implementation Agent

Implementation Stage

Relevant Legislation & Guidelines

 

Des

C

O

Dec

Good Site Practice

2.12

D1

Daily dredging volume should be spread as evenly as possible over the 24 hour period whenever practical.

Special care should be taken during lowering and lifting grabs to minimize unnecessary disturbance to the seabed.

Location: The Project Area, the disposal areas and on route between the dredging site and the disposal areas

Timing/Duration: During dredging and disposal

HEC & Dredging Contractor

 

a

 

 

WQOs for Southern and Western Buffer WCZs, WPCO

 

 

Vessels used should have adequate clearance of the seabed.

 

 

 

 

 

 

 

 

 

Barges should be fitted with tight fitting seals to their bottom openings to prevent leakage of material.

 

 

 

 

 

 

 

 

 

Grabs should be tightly closed and hoist speed is suitably low.

 

 

 

 

 

 

 

 

 

Barges should not be filled to a level which will cause overflow of materials during loading and transportation.

 

 

 

 

 

 

 

 

 

Appropriate monitoring of WQ in accordance with EM&A Manual during dredging works should be undertaken to allow the implementation of appropriate Action Plans to prevent any unacceptable WQ impacts.

 

 

 

 

 

 

 

 

 

Large objects should be removed from the grab to avoid losses from partially closed grabs.

 

 

 

 

 

 

 

 

 


 

EIA Ref.

EM&A Log Ref

Environmental Protection Measures

Location/Duration of Measures/Timing of Completion of Measures

Implementation Agent

Implementation Stage

Relevant Legislation & Guidelines

 

Des

C

O

Dec

3.11

D2

The vessel operators should be fully briefed on the following:

·      Possible presence of dolphins and porpoises in the vicinity of the Study Area and along routes to the Project Area;

·      Rules for safe vessel operation around cetaceans;

·      Slowing to 10 knots in the presence of cetaceans within the area marked on Figure B3; and

·      The dumping of chemicals, rubbish, oils etc into the waters is strictly prohibited and enforced.

Timing: In the event of spotting porpoises or dolphins

Dredging Contractor

 

a

 

 

Wild Animals Protection Ordinance, Marine Parks Ordinance and Marine Parks Regulations, Animals and Plants Ordinance, Dumping at Sea Ordinance, Waste Disposal Ordinance

 

Table B2        Recommended Maximum Daily/Hourly/Cycle Dredging Volume (in-situ Volume) for Working Zones

Season

Wet Season (April to September)

Dry Season (October to March)

Working Zone

ABn

ABs

BCn

BCs

ABn

ABs

BCn

BCs

Grab Dredger with Silt Curtains

(Grab Capacity ³ 8 m3)

m3/day

33,800

31,400

26,300

21,200

43,800

33,200

33,200

34,200

m3/hr

1,549

1,439

1,205

972

2,008

1,522

1,522

1,568

TSHD

m3/day

12,500

11,300

8,300

5,300

39,500

34,300

27,000

19,700

m3/cycle

1,432

1,295

951

607

4,526

3,930

3,094

2,257

Note:

(a)           The recommended maximum dredging rate refers to the maximum dredging rates when all dredging activities taking place at one particular working zone.  For the grab dredger option, dredging may be carried out concurrently at more than one working zones during some time periods.  In this case, the combined dredging rates during those time periods should not exceed the lowest of the maximum rates recommended for the concerned working zones.

(b)                The above maximum daily dredging rates are based on 24-hour operations. If the daily working hours are restricted, the maximum daily dredging rates should be reduced proportionally.

(c)                 The division of working zones are illustrated in Figure B2.

(d)                 For the grab dredger option, recommended maximum hourly dredging rate = 1.1 * recommended maximum daily dredging rate/24.

(e)                 For the TSHD option, recommended maximum cycle dredging rate = 1.1 * recommended maximum daily dredging rate/9.6 (where 9.6 is the number of dredging cycle in a day assumed in water quality modelling).  


Table B3        Proposed Working Schedule - Grab Dredger Option

Working Zone

Construction Programme

May-03

Jun-03

Jul-03

Aug-03

Sep-03

Oct-03

Nov-03

Dec-03

ABn

GD1

GD1

GD1

GD1

GD1

GD1

 

 

GD2

GD2

GD2

GD2

GD2

GD2

GD2

GD2

ABs

GD3

GD3

GD3

GD3

GD3

GD3

GD3

GD3

GD4

GD4

GD4

GD4

GD4

 

 

 

BCn

GD5

GD5

GD5

GD5

GD5

GD5

 

 

 

 

 

 

 

 

 

 

BCs

 

 

 

 

 

GD4

GD4

GD4

 

 

 

 

 

 

GD5

GD5

 

 

 

 

 

 

GD1

GD1

Maximum dredging rate  (m3/day)

26,300

33,200

Maximum dredging rate (m3/hr)

1,205

1,522

Note:

1.                   GD1 denotes Grab Dredger No. 1.

2.                   The above maximum daily dredging rates are based on 24-hour operations. If the daily working hours are restricted, the maximum daily dredging rates should be reduced proportionally.

Table B4     Proposed Working Schedule - TSHD Option

Working Zone

Construction Programme

May-03

Jun-03

Jul-03

Aug-03

Sep-03

Oct-03

Nov-03

Dec-03

ABn

TSHD

 

 

 

ABs

 

 

 

 

 

 

TSHD

 

BCn

 

 

 

 

 

 

 

TSHD

BCs

 

 

 

 

 

TSHD

 

 

Maximum dredging rate (m3/day)

12,500

19,700

34,300

27,000

Maximum dredging rate (m3/cycle)

1,432

2,257

3,930

3,094

Note:

1.                   TSHD denotes Trailer Suction Hopper Dredger

2.                   The above maximum daily dredging rates are based on 24-hour operations. If the daily working hours are restricted, the maximum daily dredging rates should be reduced proportionally.


FIGURE B1    ILLUSTRATION OF CAGE-TYPE SILT CURTAIN


FIGURE B2    WORKING ZONES FOR LAMMA CHANNEL IMPROVEMENT


FIGURE B3    LOCATION OF KEY PORPOISE HABITAT AROUND THE PROJECT AREA