1 INTRODUCTION

1.1 Background

Environmental Resource Management (ERM) has been appointed by the Civil Engineering Department (CED) of the Hong Kong Special Administrative Region (HKSAR) Government as the lead consultant for the “Detailed Site Selection Study for a Proposed Contaminated Mud Disposal Facility within the Airport East/East of Sha Chau Area”, the “Study”. The primary objective of the Study is to identify the most suitable sites and disposal options at the potential sites.

Contaminated mud has for a number of years been disposed of East of Sha Chau in an environmentally acceptable manner in Mud Pits I – IV north of the airport platform. Mud Pits I, II and III were purpose dredged pits that have been filled and capped with clean sand and mud. Mud Pit IV consists of three exhausted borrow sand pits – IVa, IVb and IVc of which Pit IVa and IVb have been filled with contaminated mud and are being capped with clean mud. “Project” activity associated with filling is now in progress in pit IVc.

It is expected that the mud pits will provide sufficient disposal capacity for contaminated mud until around late 2008; thereafter additional capacity must be obtained and the sites at South Brothers, and the East of Sha Chau Area have been identified as the most suitable candidates.

Figure 1.1 Study Area

South Brothers Area

BMT Asia Pacific (BMT) has been retained to perform the Marine Traffic Impact Assessment (MTIA) associated with the Study and address the marine traffic risk associated with construction and operation of the sites.

1.2 Study Brief

The scope of work for the MTIA has been developed within the Study Brief as follows:

“The Consultants shall conduct an appropriate marine traffic impact assessment to assess the impact on marine traffic arising from the construction and operation of the proposed new contaminated mud disposal facility. The objectives of the marine traffic impact assessment are to ascertain the existing and future planned/proposed marine traffic situations and patterns of the project areas including the adjacent waterways; to compare the risk level before and during construction and operation of the contaminated mud disposal facility and evaluate whether the risk levels at all stages are acceptable and to recommend mitigation measures to minimise identified impacts at various stages. The Consultants shall collect the necessary information on marine traffic flow within the Study Area and nearby waters. Some of the information would be available from the Marine Department. The Consultants shall liase with the Marine Department and shall make due allowance for marine traffic and other constraints when proposing methods of construction and disposal, the respective maximum daily frequencies and volumes of excavation/disposal, and site management procedures for the proposed contaminated mud disposal facility.”

1.3 Objective

The objective of the MTIA, addressing the requirements of the Brief, may be summarised as follows:

· To evaluate the existing and future planned/proposed marine traffic environment;

· To assess the impact on marine traffic arising from Project activity associated with the construction and operation of the proposed new contaminated mud disposal facility;

· To ascertain the associated risk levels at all stages of the Project, and

· To recommend mitigation measures to reduce the marine risks (e.g. collision, grounding, mechanical failure, manoverboard, typhoon, fire, oil pollution, etc) to acceptable levels.

For the scope of the MTIA, the area of interest has covered the immediate vicinity of the proposed site; and the adjoining fairways.

1.4 Assessment Framework

The MTIA is developed in accordance with the Formal Safety Assessment (FSA) methodology adopted by the International Maritime Organisation (IMO) as a structured approach to the assessment of marine risks, and the effectiveness of control mechanisms. The FSA methodology may be summarised as follows:

1. Identification of Hazards (What might go wrong?);

2. Assessment of Risk (How bad is the consequence and how likely is it to occur?) and where necessary;

3. Risk Control Options (Can matters be improved?);

4. Cost Benefit Analysis (What would it cost and how much better would it be?) and

5. Recommendations for Decision-Making (What actions should be taken?)

The report has been structured in the following manner to address the Brief and the FSA methodology:

· Section 2 provides information on the potential hazards impacting operations at the sites. This encompasses the marine environment, existing and future marine traffic environment, and the transport and disposal operations of contaminated mud;

· Section 3 assesses the impact of both the construction and operation phases of the contaminated mud disposal facility on the existing risk level within the Study Area, and

· Section 4 draws together the conclusions and recommendations of the assessment.

2 HAZARD IDENTIFICATION

2.1 Introduction

This section provides information on the potential hazards impacting operations at the sites. This encompasses the marine environment, existing and future marine traffic environment, and the transport and disposal operations of contaminated mud.

2.2 Site Features

The site area is illustrated in Figure 2.1:

Figure 2.1 Site Features

South Brothers

A number of features are associated with the waterspace surrounding the site, principally:

· the exclusion zones established around Hong Kong International Airport (HKIA) aims to prevent vessels from entering the zones and restrict air-draft of vessels as stipulated;

· the presence of Urmston Road, a wide heavily trafficked seaspace featuring a number of navigation aids, principally for ocean-going vessels, and

· the narrow constrained Tung Chung access channel.

Adjacent marine facilities include:

· Castle Peak Power Station, Shiu Wing Steel Works and China Cement – single piers (per facility) for supply of bulk materials;

· Sha Chau Aviation Fuel Receiving Facility – interim aviation fuel piers;

· Rivertrade Terminal – 65ha facility, 3,000m quay length for the consolidation and transshipment of cargo to midstream anchorages or Kwai Chung terminals,

· Tuen Mun Passenger Pier – provides ferry services between Tung Chung and Tuen Mun. Cross-boundary ferry services (3 berths) to the Pearl River Delta (PRD) will be provided from late 2004;

· Tung Chung Passenger Pier – provides ferry services between Tung Chung and Tuen Mun;

· Tuen Mun Immigration Anchorage (TMIA) – operates 24 hours daily for rivertrade vessels plying between Hong Kong and Pearl River Delta ports, and induces local traffic to and from marine facilities;

· Marine Cargo Terminal – provides sea links to ports throughout the Pearl River Delta and is associated with light marine activities;

· East Sea Rescue Station – features a small sheltered boat harbour formed by an enclosing breakwater and provides a base for a pair of sea rescue catamarans; and

· SkyPier I commissioned on September 2003 provides cross-boundary ferry services to/from Pearl River Delta.

It is assumed that the exact location of the pits will take account of the Airport exclusion zones and not infringe upon this absolute constraint.

It is noted that the South Brothers site does not include the alignment of the present Tung Chung dredged channel. The future marine facilities and associated marine traffic will be considered in Section 3.2.

2.3 Metocean Environment

This section reviews the “Metocean” physical environment of tidal currents, wind, wind generated waves and visibility which all posses the potential to impact operations at the site.

Tidal Levels & Currents

Tides in Hong Kong are mixed and mainly semi-diurnal, i.e. on most days in a month there are two high tides and two low tides. Large tidal ranges occur twice a month during “Spring” tides when the moon is full, “Neap” tides occur in counter-phase with smaller tidal ranges and sometimes only one high and one low tide per day.

Tidal levels and timings vary across Hong Kong waters and are responsible for driving the tidal currents across the HKSAR. Local level changes, which have limited impact on operations, are summarised in Table 2.1:

Table 2.1 Tidal Levels at Lok On Pai

Level (m)	MHHW	MLHW	MHLW	MLLW
To Chart Datum	2.22	1.64	1.00	0.42
To Principal Datum	2.07	1.49	0.85	0.27

Where: MHHW = Mean High High Waters – the average level of the higher high tides.

MLHW = Mean Low High Waters – the average level of the lower high tides.

MHLW = Mean High Low Waters – the average level of the higher low tides.

MLLW = Mean Low Low Waters – the average level of the lower low tides.

Note: Chart Datum is 0.15m below Principal Datum Hong Kong on the Chart HK1503

Source: Chart HK1503 WGS84 (dated April 2000)

Currents

Current data at the sites may be reviewed with respect to data from the Marine Department’s Digital Tidal Atlas (DTA) for the area adjacent to the Study Area, this is illustrated in Figure 2.2. The dominance of the ebb tide is illustrated. It is apparent that currents at the sites are relatively low, with wet season spring velocities not exceeding 0.5m/s, 1 knot.

Figure 2.2 Current Distribution near Site

Figure 2.2 Current Distribution near Site (cont’d)

It is apparent from Figure 2.2, that the East of Sha Chau Area will be subject to very similar currents that impact present operations. However, the currents within the South Brothers Area will be significantly less than those that presently impact dumping operations.

Wind Environment

The wind environment at the site can be illustrated with reference to data directly sourced from the Hong Kong Observatory.

Table 2.2 Wind Exposure (Based on Hourly Average), Percentage Frequency (Chek Lap Kok, Jan 85 - Dec 90 & Apr 97-May 2003)

Wind Strength (m/s)	Wind Sectors												Total
	0-30	30-60	60-90	90-120	120-150	150-180	180-210	210-240	240-270	270-300	300-330	330-360
0.1 - 0.2	7.9	8.4	21.5	17.7	7.8	5.9	5.4	4.5	4.2	4.6	5.9	6.2	100
0.3 - 1.5	7.4	7.7	20.7	16.6	6.1	4.6	4.7	4.1	3.8	4.2	5.5	5.7	91.1
1.6 - 3.3	6.1	5.8	18.1	14.6	3.3	3.5	3.8	3.2	2.7	2.9	4.2	4.6	72.8
3.4 - 5.4	3.6	2.5	13.3	11.1	1.3	2.2	2.1	1.6	1.0	1.2	2.6	2.9	45.4
5.5 - 7.9	1.3	0.8	8.0	6.4	0.5	0.8	0.4	0.4	0.1	0.3	1.2	1.1	21.3
8.0 - 10.7	0.3	0.2	4.0	2.5	0.2	0.1	0.1	0.1	-	0.1	0.4	0.2	8.2
10.8 - 13.8	-	0.1	1.3	0.7	-	-	-	-	-	-	0.1	-	2.2
13.9 - 17.1	-	-	0.3	0.1	-	-	-	-	-	-	-	-	0.4
>17.2	-	-	-	-	-	-	-	-	-	-	-	-	-

Source: Hong Kong Observatory

It is apparent that the most dominant wind direction is from east to south-east, with strong winds also impacting the sites from the north. These directions are associated with the summer and winter monsoons, respectively.

Annual wind rose for the Sha Chau Station in 2002 have also been obtained from Hong Kong Observatory’s Summary of Meteorological Observations in Hong Kong 2002 and are illustrated in Figure 2.3.

Figure 2.3 Wind Rose at Sha Chau and the Brothers in 2002

Wave Height

The action of wind at the site, blowing across the sea “fetches” will be different for the two sites under consideration and develop distinct wave characteristics. The maximum operational waves (based on a limiting wind speed of approximately 25knots, 12.5 m/s) associated with the two sites has been calculated using “fetch” limited wind driven forecast methods.

Table 2.3 Preliminary Maximum Operational Wave Distribution, 25 knot wind (East of Sha Chau)

Parameter	Direction Sector
	N	NE	E	SE	S	SW	W	NW
	0	45	90	135	180	225	270	315
Average Fetch Length (m)	4,500	4,500	4,500	4,500	1,500	3,000	> 10,000	6,750
Water Depth (m) *	10	12	5	7.5	4	6	5	8
Max Operational Wave Height, Hs (m)	1.2	1.2	1.1	1.2	0.7	1.0	1.3	1.4

Source: BMT

* - an allowance for storm surge has been included within the assessment of waterdepths

Table 2.4 Preliminary Maximum Operational Wave Distribution, 25 knot wind (South Brothers)

Parameter	Direction Sector
	N	NE	E	SE	S	SW	W	NW
	0	45	90	135	180	225	270	315
Average Fetch Length (m)	4,500	6,750	1,500	1,050	750	1,500	2,700	9,000
Water Depth (m) *	7	10	3	2.2	2.2	2	2	4
Max Operational Wave Height, Hs (m)	1.2	1.4	0.7	0.5	0.5	0.6	0.7	1.2

Source: BMT

* - an allowance for storm surge has been included within the assessment of waterdepths

In a similar manner to the tidal current environment it can be identified that the South Brothers site is considerably less exposed than the East of Sha Chau Area.

Visibility

The transhipment of the contaminated mud to the facilities will also be impacted, like all other craft in Hong Kong, by changes in the visibility within the approach channel and along the transit routes. Table 2.5 provides the details on percentage frequency of visibility within Hong Kong Waters in 1999-2002.

Table 2.5 Annual Percentage of Restricted Visibility in 1999-2002

Month	1.0km	3.0 km	5.0 km	10.0 km
Year	0.1%	1.5%	4.9%	27.4%

Source: Summary of Meteorological Observations in Hong Kong 1999-2002, Hong Kong Observatory

It is apparent that periods of very low visibility (<1.0 km) are rare with only 0.4 days per year being impacted in such a manner. This is not anticipated to hazard Project operations.

2.4 Present Marine Traffic Environment

Existing information on traffic levels within the HKSAR western waters has been collated from a number of data sets held by BMT to assist in the risk assessment of barging operations. Principal details were extracted from the following available sources:

· Radar track data on the traffic activities in HKSAR Western Waters, June 2003;

· 12 day time-lapse visual survey data at Castle Peak power stations, December 2001,

· 12 day time-lapse visual survey data at Siu Lam, June-July 2003, and

· First Ferry service schedules between Tuen Mun and Tung Chung.

The compilation of the survey data is illustrated in Figure 2.4 which presents estimates of average hourly traffic density during daylight periods within HKSAR western waters.

Figure 2.4 Background Traffic Density

The high density of vessel movements within the Urmston Road channel is clearly apparent from Figure 2.4, with decreasing vessel activity the further south from this area – i.e. towards the potential disposal sites.

Table 2.6 summarises the total volume of traffic movements sampled for a typical day.

Table 2.6 Vessel Class and Volume in the Study Area in 2003

Class of Vessel	Number of Vessels (24 hours)
Ocean-going	25
Rivertrade	595
Fast Ferry	130
Tug and Tow	155
Fast Launch	135
Others ^(1)	460
Total	1,500

Note: rounding to 5 vessels per day

(1) - Others include: Trading, Barges, Fishing and Pleasure Vessels

2.5 Historic Hazards within the Study Area

The principal hazard posed by marine traffic is the potential for collision between barges associated with mud transport operations, or the target barge, and other traffic. The consequences of collision incidents within the HKSAR water as a whole, and what may be assumed for the present assessment, has been summarised in Table 2.7.

Table 2.7 Consequence of Vessel Collisions (within HKSAR waters)

Incident		1993	1994	1995	1996	1997	1998	1999	2000	2001	2002	Average
Collision / Contact	Incident	286	239	327	283	246	236	246	302	242	236	264
	Injury	44	18	25	20	38	15	34	48	33	27	30
	Fatality	6	2	0	2	5	6	12	0	1	14	5
Injury/Collision or Contact		0.15	0.08	0.08	0.07	0.15	0.06	0.14	0.16	0.14	0.11	0.11
Fatality/Collision or Contact		0.02	0.01	0.00	0.01	0.02	0.03	0.05	0.00	0.00	0.06	0.02
Frequency of other fatalities as a proportion of reported collision fatalities												1.27

Others = Stranding/Groundings, Foundering/Sinking, Fire/Explosion. Man Over Board, Capsized Listing & Others

Source: Marine Accident Investigation Branch http://www.mardep.gov.hk/en/publication/pdf/portstat_2_y_e1.pdf

It is identified that, on average the injury rate is 11% with a fatality rate per collision of 2%.

Figure 2.5 illustrates the average annual reported collisions within the Study Area for 2001 - 2003. 14 collisions are identified, approximately (14/200) 7% of the HKSAR occurrence of collision incidents in 2001-2003.

Figure 2.5 Average Annual Reported Collisions in the Study Area (2001-2003)

2.6 Current Contaminated Mud Marine Operation

Since December 1992, a total of about 32 Mm³ of contaminated mud has been placed in the disposal pits located East of Sha Chau.

Figure 2.6 Current CMP sites (East of Sha Chau)

The future operation of the mud dumping operations will be almost identical to current activity, in that a target barge will be stationed on site and a workboat escort incoming split-hopper barges, one at a time to the site. This operation ensures that marine activity at the site is not significant, however a suitable site for the temporary mooring of waiting barges, if any, will be required.

Table 2.8 and 2.9 summarise the disposal activities from January to November 2003. An overall average of 16 movements per day have been associated with the disposal and capping activities. This equates to 1% of the traffic within the local waterways.

Table 2.8 Disposal Activity in January – November 2003 (within HKSAR waters)

	Contaminated Mud Disposal Movements (Daily)
Month	Max	Min	Mean	Standard Deviation
Jan-03	15	0	6.32	4.87
Feb-03	8	0	1.64	2.26
Mar-03	4	0	2.06	1.63
Apr-03	1	0	0.30	0.47
May-03	7	0	1.23	1.61
Jun-03	6	0	1.20	1.58
Jul-03	9	0	3.35	2.87
Aug-03	11	0	5.52	2.92
Sep-03	9	0	4.13	2.40
Oct-03	19	1	9.94	5.23
Nov-03	19	0	7.97	4.68
Overall	19	0	3.97	1.55

Table 2.9 Capping Activities in January – November 2003 (within HKSAR waters)

	Capping using Uncontaminated Mud Movements (Daily)
Month	Max	Min	Mean	Standard Deviation
Jan-03	7	0	0.58	1.43
Feb-03	4	0	1.86	1.53
Mar-03	0	0	-	-
Apr-03	8	0	2.63	2.86
May-03	8	0	4.61	2.16
Jun-03	9	0	5.37	2.08
Jul-03	8	0	6.06	2.38
Aug-03	9	0	4.97	2.56
Sep-03	13	0	7.03	2.80
Oct-03	12	4	7.19	2.14
Nov-03	14	4	10.17	2.82
Overall	19	0	3.97	1.55

The operations to date have been conducted with an acceptable level of safety.

2.7 Summary

A review of the existing constraints and hazards has been conducted and the following summary developed:

· Current operations, and future proposed sites are set south of busy marine channels of the Urmston Road, adjacent to restricted waterspaces associated with HKIA, and local navigation channels to Tung Chung which will need to be addressed as absolute constraints on siting during the detailed pit layout exercise;

· The site East of Sha Chau Area will be subject to very similar currents that impact present operations. However, currents within the South Brothers Area will be significantly less. In a similar manner it can be identified that the South Brothers site is considerably less exposed to wave impacts that that East of Sha Chau Area;

· It is apparent that periods of very low visibility (<1.0 km) are rare with only 0.4 days per year being impacted in such a manner,

· There are approximately 1,500 vessel movements per day through the waterspaces adjacent to the sites;

· The historic activity level of disposal and capping operations (at an average of 16 movements per day) equates to approximately 1% of marine traffic within the Study Area; and

· Operations to date have been conducted in a safe manner.

Having reviewed the operational historic performance and surrounding area, there is no significant marine constraints to the mud disposal operators.

3 risk assessment

3.1 Introduction

This section assesses the impact of both the construction and operation phases of the contaminated mud disposal facility on the existing risk level within the Study Area. Marine risk has been reviewed for two principal scenarios:

· The collision risk during navigation within the whole Study Area, and

· The collision risk during operations at or near the target barges at the sites.

The following 3 time horizons have been examined within the risk assessment:

· Present (2003) activity;

· 2008 Future case (before the HK-Macau-Zhuhai Bridge); and

· 2010 Future case (after the HK-Macau-Zhuhai Bridge).

3.2 Future Marine Facilities

A number of future facilities are planned within the Study Area which may impact the risks levels within the local waterspace.

Tuen Mun Area (TMA) 38

A number of facilities are intended to be sited on TMA 38. These include a Recovery Park (RP), a proposed Construction Waste Barging Facility (CWBF), proposed Construction and Demolition Materials Recycling Facility (C&DMRF), chemical tanker berth and a proposed Logistics Park. The dominant vessel activity associated with these facilities will be barges and Rivertrade vessels.

PAFF at TMA 38

A Permanent Aviation Fuel Facility (PAFF) at Tuen Mun Area (TMA) 38 has been proposed to meet the future demands of the airport and to supersede the present Aviation Fuel Facility at Sha Chau in around 2005/2006. The PAFF tanker jetty will be configured as a twin berth “island structure” set about 200m from the existing shoreline. The twin jetties will be designed to allow the berthing, unberthing and mooring of tankers ranging between 10,000 and 80,000 DWT.

SkyPier

SkyPier at Chek Lap Kok was commissioned in late September 2003 linking HKIA with passengers within the PRD. The ferry service currently operates to four ports - Shekou, Shenzhen, Humen and Macau and is likely to extend at a later date to Guangdong's Zhuhai, Guangzhou and Zhongshan.

North Lantau coastline

North Lantau Development Tung Chung Phase 3 is expected to generate material requiring dredging at a maximum annual rate of 920,000 m³ during 2009. The dredging works, which will be conducted using grab dredgers, translate to an average assumed production of 2,600 m³ per day. These works are considered to be of small scale and are not expected to interact in any significant way with works at CMP V.

North Lantau Developments are associated with various reclamations in the planning process for the North Lantau coastline between Tung Chung and Tai Ho. These include a Lantau Logistics Park (formerly Value Added Logistics Park), Potential Theme Park and New Town Developments. Timelines for all the above reclamations are not available nor details on their intended construction techniques. It is unknown at present whether the works will involve dredging or drained reclamations. It is expected that the latter method will be used and only minor dredging works will be undertaken for the seawall trenches.

The “Lantau Logistics Park” (LLP) has been proposed for a site at Siu Ho Wan (SHW). It is envisaged that the proposed LLP will:

· provide a secure operating environment connected to other locations on the Hong Kong International Airport (HKIA) and other logistics platforms;

· establish an air cargo express hub incorporating time critical and time definite activities and

· create a multi-modal capability including integrated sea, river and land linkages.

The seaward access route will utilize the deeper water available from the northeast of the site but have to keep clear of the MD’s planned tanker moorings off Sham Shui Kok and FM/CEDD’s planned multipit contaminated mud disposal facility. This obligation will fall on the LLP project proponent.

Northshore Lantau Feasibility Study – Reclamations at Yam O was assessment as part of the above feasibility study (a Schedule 3 EIA) in which it was highlighted that the land would be formed through drained reclamations. Only minimal dredging would be required for the seawall trenches. Given the distance to the South Brothers/East of Sha Chau it is reasonable to assume that the plumes generated from the seawall trench dredging would not overlap with activities at CMP V.

Road Infrastructure

It is anticipated that Shenzhen Western Corridor and Hong Kong- Zhuhai-Macau Bridge will reduce Rivertrade marine traffic and cross-boundary ferry services through the Study Area.

The Tuen Mun to Chek Lap Kok link which passes to the east of the East of Sha Chau site and to the west of the South Brothers site. The planning for the link is in a very preliminary stage, however, it is expected that the highway will be both in tunnel form and that the main dredging works will take place at the landing/launching sites and will be minor. As the link is in the conceptual phase, neither construction information or programme details are available. Consequently, the project will not be examined in the cumulative assessment.

3.3 Basis for Forecast

Future traffic activity that may impact the Project has been forecast on the basis of a methodology developed and endorsed within the recently completed MARA Study (Study on Marine Traffic Risk Assessment for Hong Kong Waters). The methodology takes account of international and local factors and makes reference to a number of data sources, as identified in Table 3.1.

Table 3.1 Vessel Classes with Data Sources for Forecasting

Class of Vessel	Source of Forecast
Ocean-going	(1), (2)
Rivertrade	(1), (2)
Fast Ferry	(3), (4), (5)
Tugs and Tow	(1), (2)
Fast Launch	(3), (4), (5)
Others	(3), (4), (5)

(1) – Port, Maritime and Logistics Development Unit (2001) “Port Cargo Forecast 00/01”

(2) – Port, Maritime and Logistics Development Unit (2003) “Summary Statistics on Port Traffic of Hong Kong”

(3) – Marine Department (2002) “Assessment of Typhoon Shelter Space Requirements 2002 – 2021”

(4) – Marine Department (1996-2002) “Port of Hong Kong Statistical Tables”

(5) – Transport Department (2001) “A Review on the Future Development of Domestic Passenger Ferry Services in Hong Kong”

The Port Cargo Forecast 2000/2001 (PCF 00/01) drives the growth of international and Mainland cargo vessels, while MD’s assessment of typhoon shelter requirements addresses vessel activity associated with the domestic economy. The forecast data from PCF 00/01 is summarised in Table 3.2.

Table 3.2 Annual Cargo Increases projected by Port Cargo Forecasts 00/01

Cargo Throughput	2002 ^(1)	2003 ^(2)	Port Cargo Forecasts
			2005	2010	2015	2020	2030
‘000 TEU ^(3)	19,144	21,071	24,927	29,724	36,051	40,528	46,950

Source: (1) Marine Department (2002) “Port of Hong Kong Statistical Tables”

(2) by linear interpolation

(3) TEU = Twenty-foot Equivalent Units.

Table 3.3 provides a summary of traffic activity forecast in the Study Area for 2008 & 2010, based on the “MARA methodology” and PCF 00/01.

Table 3.3 Daily Vessel Class and Volume in the Study Area

Type of Vessel	Population per Vessel	Number of Vessels
		2008 (without HK-Macau-Zhuhai Bridge)	2010 (with HK-Macau-Zhuhai Bridge)
Ocean-going	20	25	25
Rivertrade	5	565	495
Fast Ferry	50	145	145
SkyPier Ferry	150	45	35
Tug and Tow	10	150	130
Fast Launch	5	130	135
Others	10	480	480
Total		1,540	1,445

Note: rounding to 5 vessels per day

3.4 Marine Activity Associated with Forecast Barge Operations

It is anticipated that there will be 3 main types of marine activities conducted at the proposed sites:

· Construction – Grab Dredging & Trailer Dredging (East of Sha Chau only);

· Operation – Barge Disposal & Trailer Disposal; and

· Capping – Barge Capping.

The disposal activity is summarised in Table 3.4.

Table 3.4 Disposal Activity (within HKSAR waters)

Construction
Grab Dredging		Trailer Dredging (East of Sha Chau Only)
Dredging Rate	50,000 m^3 wk^-1	North Lantau Disposal
No of Dredgers	2	No of loads per day	25
Total Volume Dredged	100,000 m^3 wk^-1	No of loads per week	175
Barge Capacity	800 m^3	South Cheung Chau Disposal
Total Barges per Week	125	No of loads per day	5.5
-	-	No of loads per week	38.5

Table 3.4 Disposal Activity (within HKSAR waters), continued

Operation
Barge Disposal		Trailer Disposal
Disposal Rate	26,700 m^3 day^-1	Disposal Rate	26,700 m^3 day^-1
Barge Capacity	800 m^3	Barge Capacity	4,500 m^3
Total Barges per day	33.3	Total Barges per day	5.9
Total Barges per Week	233	Total Barges per week	41
Capping
Barge Capping
Capping	50,000 m^3 wk^-1	Total Barges per week	63

The projected maximum daily disposal activity from 2005 to 2015 is summarised in Table 3.5. It is found that the peak activities will occur between 2007 to 2012.

Table 3.5 Projected Maximum Daily Disposal Activity

Site	2005	2006	2007	2008	2009	2010	2011	2012	2013	2014	2015
East of Sha Chau
1	33	33	51	42	42	51	51	51	33	9	0
2	33	33	58	67	67	58	58	58	33	9	0
3	33	33	58	40	40	31	31	31	6	9	0
4	33	33	39	48	48	39	48	42	33	9	0
5	33	33	39	20	20	11	20	15	6	9	0
Max	33	33	58	67	67	58	58	58	33	9	0
South Brothers
6	0	0	33	51	24	24	24	24	15	9	9
7	0	0	33	51	51	67	51	51	42	33	9
Max	0	0	33	51	51	67	51	51	42	33	9

Note:

1 - East of Sha Chau - Grab Dredging, Barge Disposal and Barge Backfilling

2- East of Sha Chau - Trailer Dredging, Barge Disposal, Barge Backfilling and North Lantau Uncontaminated Disposal

3 - East of Sha Chau - Trailer Dredging, Trailer Disposal, Barge Backfilling and North Lantau Uncontaminated Disposal

4 - East of Sha Chau - Trailer Dredging, Barge Disposal, Barge Backfilling and South Cheung Chau Uncontaminated Disposal

5 - East of Sha Chau - Trailer Dredging, Trailer Disposal, Barge Backfilling and South Cheung Chau Uncontaminated Disposal

6 – South Brothers - Grab Dredging, Barge Backfilling and Barge Capping

7 – South Brothers - Grab Dredging, Trailer Backfilling and Barge Capping

The projected maximum activity between 2007 – 2012 is approximately double the present maximum daily activity, but consistent with past peaks in activity (i.e. during disposal of material from CT9).

Environmental dumping restrictions will limit the number of barges accessing the target barge for dumping operations to 3 per hour. These barges are typically less than 50m in width and of the split hopper variety. As such they will not pose an airdraft hazard to marine operations.

The future sites for the generation of contaminated mud are all sited within the Central or Western harbour areas. As such traffic will access the site from the east (via the Ma Wan/Kap Shui Mun channels).

3.5 Risk Assessment Guidelines

Risk acceptability within Hong Kong is frequently assessed with respect to Potential Loss of Life (PLL). The PLL, or “annual fatality rate” expresses the risk to the population as a whole, and is the sum of each anticipated event and the associated fatalities. All fatalities are assumed equally important, irrespective of the number of lives which may be lost simultaneously in a major accident.

Societal risk is also expressed in the form of an F-N curve, which represents the cumulative frequency (F) of all event outcomes leading to N or more fatalities. This representation of societal risk highlights the potential for accidents involving large numbers of fatalities. There are commonly three regions identified:

· Acceptable region where risk is broadly acceptable;

· ALARP region where risk is tolerable providing it has been reduced to a level As Low As Reasonably Practicable, and

· Unacceptable region.

Hong Kong societal risk criteria (for the assessment of fixed Hazardous Installations) is illustrated in Figure 3.1. This may be used as a framework for the assessment of marine risk acceptability – although it must be stressed it is purely a guideline in this context and does not have the statutory context of the EIA ordinance.

Figure 3.1 HKSAR Risk Criteria

3.6 Collisions and Traffic Density

In order to conduct a comparative analysis of marine traffic risk it was necessary to review the traffic density at the two sites, and conduct a projection of the number of annual collisions, on the basis of the distribution of marine traffic.

Prior to conducting such an assessment of the future marine risk environment it is necessary to identify whether the assessment based on the traffic density can represent the traffic collision environment within Study Area.

To accomplish this, the traffic density was tracked from 9 days radar data for the period between 00:00 – 24:00 hours during each day. The collision profile in the Study Area has been identified in Figure 2.5. The correlation between traffic density and collisions is illustrated in Figure 3.2.

For the correlation the best agreement with data is when R² = +/-1, no correlation is present when R² = 0.

Figure 3.2 Validation of Relationship between Traffic Density & Collisions

It can be seen that there is a good general correlation (R²=-0.7) between the distribution of vessel density and reported collision incidents with 100% of the data identified within a band of +/- 1.0 collisions. Figure 3.3 shows the regional distribution of projected collisions developed based on the traffic density. As ex pected, the model considered that the busy channels in the Western Waters and Urmston Road pose the highest risk of collisions.

Figure 3.3 2003 Baseline – Projected Collisions

The satisfactory agreement of the simple traffic density model (for this waterspace) allowed projections of future incidents associated with Project operations to be undertaken with some confidence.

3.7 Baseline Risk Assessment

Transit Collision Risks

The model results for the baseline assessment of collisions are summarised in Table 3.6.

Table 3.6 Forecast Background Data

	2003 Baseline	2008	2010
Background
Background Collisions / year	12.6	13.9	13.3
Fatalities / year	0.3	0.3	0.3
Population at Risk	6,132,000	8,860,000	8,121,000

The distribution of projected collisions associated with background traffic are illustrated in Figures 3.4 and 3.5.

Figure 3.4 2008 Scenario – Projected Collisions

Figure 3.5 2010 Scenario – Projected Collisions

It is found that the projected collisions will be distributed in a similar manner as the baseline 2003 case and the projected collisions will focus on the main navigation channels. The proposed sites are not located in these high risk areas.

Disposal Operations Collision Risk

Operations within the disposal sites, which have the potential for collisions, have been examined for the 2008 & 2010 timeframes. However, prior to this it is instructive to review the risks at the present site. Table 3.7 benchmarks the collision risks at the 2003 baseline year.

Table 3.7 Collision Risks at Present Disposal Sites (2003 baseline)

Annual Collision rate (2001-2002)	0.5
Daily Traffic Density at Site Grids	753
Daily barge operations at site	13
Collision Rate per Barge per Traffic Density	5.1x10^-5

By assuming the collision risks occurring at the same manner at the baseline year, the projected collision rate induced by the disposal activities are shown in Tables 3.9 and 3.11.

Management of Waiting Barges

The key issue associated with operation of the site is anticipated to be the management of any barges waiting at the site to be brought to the target barge. It is recommended that an open waterspace approximately 1,000m south south-east of Tsz Kan Chau is used for this purpose. This will be at the eastern extremity of the dumping site and away from the entrance to Tung Chung Channel. Should future users, such as the LLP, inject significant marine traffic into the waterspace a dedicated access channel may be necessary for the LLP – this issue must be addressed during the assessments for this facility.

3.8 East of Sha Chau Risk Assessment

Transit Collision Risks

The accumulated transit risks induced by the disposal activities at the East of Sha Chau area are shown in Table 3.8. It is assumed that the barge movement to/from the sites will increase the traffic density in 5 grid areas, hence an arrival and departure will increase the total traffic density by 10 vessels for each barge arrivals.

Table 3.8 Forecast Collision Frequency (East of Sha Chau) & Comparison

	2003 Baseline ^(*^)	2008	2010
Site	Present Site	East of Sha Chau
Daily Disposal Activity ^(1)	13	67	58
Induced Collisions / year ^(2)	0.22	1.14	0.99
Induced Fatalities ^(3)	0.004	0.023	0.023
Population at Risk in Barges ^(4)	18,000	97,000	84,000
Study Area
Potential Loss of Life ^(5)	5x10^-8	4x10^-8	4x10^-8

(*) – At 2003 baseline year, disposal site is located at East Sha Chau (see Figure 2.6)

(1) – from Table 3.5 for 2008 & 2010

(2) – (1) x 10 x 0.0017 collision / traffic density, gradient from Figure 3.2

(3) – (2) x0.02 fatality / collision

(4) – (1) x 4 persons / vessel x 365 days / year

(5) – Accumulated fatalities / accumulated population from Table 3.6 & 3.8

Disposal Operations Collision Risk

The anticipated collision risk during disposal operations at the target barge site is summarised in Table 3.9.

Table 3.9 Forecast Collision Frequency at Sites (East of Sha Chau)

	2008	2010
East of Sha Chau
Traffic Density at Site Grids ^(1)	357	332
Maximum Daily Barge Operations ^(2)	67	58
Projected Collision Rate ^(3)	1.22	0.98
Projected Fatality Rate ^(4)	0.02	0.02
Annual Population ^(5)	619,040	569,400
Potential Loss of Life ^(6)	4x10^-8	3x10^-8

(1) – from Radar Tracking x Growth Factors

(2) - from Table 3.5 for 2008 & 2010

(3) – (1) x (2) x 5.1x10^-5 from Table 3.7

(4) – (3) x 0.02 fatality per collision

(5) – [(1)+(2)] x 4 persons per vessel x 365 days per year

(6) – (4) / (5)

With reference to Tables 3.8 and 3.9, it can be identified that the hazard to life of the proposed disposal activity falls well within the acceptable level and hence no specific mitigation measures are required for the navigation of the barges to the sites.

It was identified that the accumulated Potential Loss of Life in the presence of proposed disposal activity is at the order of 10^-8, which is similar to that of the background traffic and the baseline. It is believed that the proposed project at South Brothers area will be conducted as safely as at the present site, in terms of collision risks.

3.9 South Brothers Risk Assessment

The accumulated transit risks induced by the disposal activities at the South Brothers area are shown in Table 3.10. In a similar manner to previously it is assumed that the barge movement to/from the sites will increase the traffic density in 5 grid areas, hence an arrival and departure will increase the total traffic density by 10 vessels for each barge arrivals.

Table 3.10 Forecast Collision Frequency (South Brothers) & Comparison

	2003 Baseline ^(*^)	2008	2010
Site	Present Site	South Brothers
Daily Disposal Activity ^(1)	13	51	67
Induced Collisions / year ^(2)	0.22	0.69	0.91
Induced Fatalities ^(3)	0.004	0.014	0.018
Population at Risk in Barges ^(4)	18,000	74,000	97,000
Study Area
Potential Loss of Life ^(5)	5x10^-8	4x10^-8	4x10^-8

(*) – At 2003 baseline year, disposal site is located at East Sha Chau (see Figure 2.6)

(1) – from Table 3.5 for 2008 & 2010

(2) – (1) x 10 x 0.0017 collision / traffic density, gradient from Figure 3.2

(3) – (2) x0.02 fatality per collision

(4) – (1) x 4 persons per vessel x 365 days per year

(5) – Accumulated fatalities / accumulated population from Table 3.6 & 3.10

Disposal Operations Collision Risk

The anticipated collision risk during disposal operations at the target barge site is summarised in Table 3.11.

Table 3.11 Forecast Collision Frequency at Sites (South Brothers)

	2008	2010
South Brothers
Traffic Density at Site Grids ^(1)	67	65
Maximum Daily Barge Operations ^(2)	51	67
Projected Collision Rate ^(3)	0.18	0.22
Projected Fatality Rate ^(4)	0.004	0.004
Annual Population ^(5)	173,740	192,720
Potential Loss of Life ^(6)	2x10^-8	2x10^-8

(1) – from Radar Tracking x Growth Factors

(2) - from Table 3.5 for 2008 & 2010

(3) – (1) x (2) x 5.1x10^-5 from Table 3.7

(4) – (3) x 0.02 fatality per collision

(5) – [(1)+(2)] x 4 persons per vessel x 365 days per year

(6) – (4) / (5)

With reference to Table 3.10, it can be identified that the hazard to life of the proposed disposal activity falls well within the acceptable level and hence no specific mitigation measures are required for the navigation of the barges to the sites.

It was identified that the accumulated Potential Loss of Life in the presence of proposed disposal activity is at the order of 10^-8, which is similar to that of the background traffic and the baseline. It is believed that the proposed project at South Brothers area will be conducted as safely as at the present site, in terms of collision risks.

3.10 Summary

A risk assessment of the proposed Project at East of Sha Chau / South Brothers has been conducted. The following conclusions have been developed:

· A baseline risk assessment has been carried out to correlate local traffic density and annual collision rates to provide a tool for the assessment of future risks. Such a relationship has been identified, and the good accuracy is considered to provide a satisfactory and reliable foundation for assessment of the future disposal activity.

· From the time horizon of the Study (2005-2015), the peak year 2008 and 2010 scenarios were selected for the Quantitative Risk Assessment of the risk to life in associated with the proposed disposal activity. For each of these years, it is identified that the hazard to life falls well within the acceptable level. Hence, no specific mitigation measures are required for the disposal activity at the proposal sites.

· This finding is consistent with the perception of marine safety in the region of present disposal activity.

4 conclusion and recommendation

4.1 Introduction

A Marine Traffic Impact Assessment (MTIA) has been conducted for the proposed disposal activity at East of Sha Chau / South Brothers. The MTIA has been conducted to identify if the risk associated with traffic activity at future sites falls within acceptable levels.

4.2 Hazard Identification

A review of the existing constraints and hazards has been conducted and the following summary developed:

· Current operations, and future proposed sites are set south of busy marine channels of the Urmston Road, adjacent to restricted waterspaces associated with HKIA, and local navigation channels to Tung Chung which will need to be addressed as absolute constraints on siting during the detailed pit layout exercise;

· The site East of Sha Chau Area will be subject to very similar currents that impact present operations. However, currents within the South Brothers area will be significantly less. In a similar manner it can be identified that the South Brothers site is considerably less exposed to wave impacts than that East of Sha Chau Area;

· It is apparent that periods of very low visibility (<1.0 km) are rare with only 0.4 days per year being impacted in such a manner,

· There are approximately 1,500 vessel movements per day through the waterspaces adjacent to the sites;

· The historic activity level of disposal and capping operations (at an average of 16 movements per day) equates to approximately 1% of marine traffic within the Study Area, and

· Operations to date have been conducted in a safe manner.

4.3 Risk Assessment

A risk assessment of the proposed Project at East of Sha Chau / South Brothers has been conducted. The following conclusions have been developed:

· A baseline risk assessment has been carried out to correlate local traffic density and annual collision rates to provide a tool for the assessment of future risks. Such a relationship has been identified, and the good accuracy is considered to provide a satisfactory and reliable foundation for assessment of the future disposal activity.

· From the time horizon of the Study (2005-2015), the peak year 2008 and 2010 scenarios were selected for the Quantitative Risk Assessment of the risk to life in associated with the proposed disposal activity. For each of these years, it is identified that the hazard to life falls well within the acceptable level. Hence, no specific mitigation measures are required for the disposal activity at the proposal sites.

· This finding is consistent with the perception of marine safety in the region of present disposal activity.

4.4 Summary

Both present and future risk levels fall well within acceptable limits - this finding is consistent with the perception of marine safety in the region of present disposal activity.

However, while the risk assessment projects that future risks will be acceptable this is dependent upon the continued vigilance of the operator in the safe conduct of the disposal activity.