¡ Provision for the additional capacity projected in the Airport Master Plan 2030 (MP2030) – in the absence of this criterion, the third runway would not meet the need identified in Chapter 2 of this report;

¡ Provision for the safe approach, landing and take-off procedures required by the Civil Aviation Department (CAD) – this is a mandatory requirement that overrides most other considerations, as passenger and crew safety must never be compromised;

¡ Be optimally located and configured – this affects the effectiveness of the third runway and impacts on the ability of the third runway to meet forecasted demand;

¡ Provision of sufficient space for all other related facilities (e.g. passenger terminal expansion and new concourses, Baggage Handling System (BHS), Automated People Mover (APM), aircraft aprons, taxiways, navigation aids, air traffic control tower, etc.) needed to support the operation of a third runway; and

¡ Be compatible with the operation of the existing HKIA.

3.2.2 Review of Existing Configuration and Constraints

Current Airport Runway Configuration

3.2.2.1 At present, there are two runways at HKIA. These parallel runways are aligned along 07/25 orientation (i.e. runways aligned along an axis of 70° and 250° from the north). The runways are slightly staggered with a 1,540 m separation [1].

Major Constraints to the Existing Runway Operations

3.2.2.2 The majority of constraints that affect runway operations relate to safety requirements. While airports around the world are subject to international rules and regulations that control (or constrain) their operation, there are some constraints which are specific to the local environment. The main locally-specific constraints affecting operation of the two existing runways at HKIA include:

¡ Topography;

¡ Territorial boundaries;

¡ Anthropogenic (man-made) structures;

¡ Populated areas; and

¡ Current runway configuration.

Topography, Territorial Boundaries and Anthropogenic Structures

3.2.2.3 Topography affects runway operations by physically restricting flight movements. There is high terrain to the south of HKIA on Lantau Island and to the north-east of the airport in North West New Territories [3]. The permanent presence of high terrain means that only certain approach and departure routes are viable from a safety perspective [1].

3.2.2.4 Territorial boundaries affect runway operations by restricting the permitted flight routes for arrivals and departures from outside of Hong Kong Special Administrative Region (HKSAR). This constraint is however partially negotiable.

3.2.2.5 Man-made structures, particularly major infrastructure and superstructures, can also restrict flight movements as well as the vertical climb and descent requirements for aircraft. In some instances, certain built facilities are associated with ‘no fly’ zones that effectively bar all routes over that area.

Populated Areas

3.2.2.6 Populated areas can affect the operation of a runway by imposing operational, temporal, and aircraft restrictions on runway operations, such as restrictions on aircraft types (i.e. those that do not comply with certain noise standards), take-off / landing procedures and routes and operating times. These measures are usually adopted for aviation noise abatement reasons rather than because of safety issues. The noise control initiatives specified by CAD for the existing operation of the runways at HKIA include the following [2]:

¡ Aircraft arriving during midnight to 07:00 am are arranged to land from the southwest, subject to acceptable wind direction and safety consideration;

¡ Aircraft departing to the northeast of the airport during 11:00 pm and 07:00 am are required to use a southbound route via the West Lamma Channel, subject to acceptable operational and safety consideration;

¡ Aircraft departing to the northeast of the airport are required to adopt the International Civil Aviation Organization (ICAO) Noise Abatement Departure Procedures;

¡ Aircraft which can make use of the satellite navigation technology are recommended, when departing to the northeast of the airport between 11:00 pm and 07:00 am, to adopt the “Radius-to-Fix” turn procedures when making south turn to the West Lamma Channel so as to reduce the noise impact to residents in the areas;

¡ All noisy aircraft* are barred from landing and taking off in Hong Kong (* noisy aircraft refer to those which do not comply with the noise standard in Chapter 3 of Annex 16 Volume I, Part II to the Convention on International Civil Aviation.); and

¡ All aircraft on approach to HKIA from the northeast during 11:00 pm and 07:00 am are encouraged to adopt the continuous descent approach (CDA), which involves aircraft flying higher and normally on a low power / low drag configuration.

Configuration of Existing Two Runways

3.2.2.7 The physical location of the existing two runways has created some operational constraints, in terms of interdependence of aircraft management (take-off and landing as well as taxiing and queuing procedures) and in this case, safety requirements are the main drivers. For airports with more than one runway, the taxiway system may maintain taxiing routes that create additional restrictions on the maximum capacity of the runways (i.e. runway crossings or incursions).

3.2.2.8 In theory, the most effective mode of operation for two runways is the mixed mode of operations¹. In Hong Kong this mode theoretically allows a maximum capacity of 44 air traffic movements (ATMs) per hour on each runway [3]. However, this theoretical maximum capacity cannot be achieved with the existing two-runway system (2RS) at HKIA, because in Hong Kong the airport is required to operate under a “dependent” mixed mode for the following reasons [3]:

¡ The terrain on Lantau Island constrains the South Runway’s mixed mode capacity to 34 ATMs per hour.

¡ The terrain to the east of HKIA, such as Tai Mo Shan, and airport traffic interaction with Macao airport to the west, prevents the current two-runway configuration from accepting independent parallel approaches.

¡ The South Runway’s constrained circumstance requires a larger spacing between landing aircraft, with similar requirements on the North Runway, thereby preventing the runways from achieving a theoretical maximum capacity under a mixed mode operation.

1 Mixed mode refers to an operation mode of the runway whereby both ‘departures’ and ‘arrivals’ is permitted on the same runway. ‘Dependent’ mixed mode refers to a mixed mode of operations that is constrained by factors other than the maximum capacity of the runway.

3.3 Consideration of Alternatives for the Third Runway Alignment

3.3.1 General

3.3.1.1 The alignment of a runway is governed by the geographical location as well as the predominant wind direction for landings and take-offs. Considerations for runway alignment form the first major foundation for any airport project, as runway alignment effectively governs available options for future layout and operation of airport facilities and can result in permanent operational constraints on an airport.

3.3.1.2 This section describes the methodology adopted for consideration and evaluation of different runway alignment options as well as summarising the assessments leading to identification of a shortlist of alignment options.

3.3.2 Methodology for Evaluation of Runway Alignment Options

3.3.2.1 To evaluate the runway alignment options, both a set of evaluation criteria and a long list of runway options were first defined. A process was then developed for reviewing each option against the relevant criteria to identify differences in performance between options.

3.3.2.2 Considering the constraints described in Section 3.2.2 as well as the potential additional constraints associated with construction and operation of a new runway and airport facilities, the main criteria for analysis of the various third runway alignment options are described in Table 3.1 below.

Table 3.1: Alignment Options Evaluation Criteria [1]

Major Criteria	Key Considerations	Criteria Importance¹
Airport integration (aprons and terminals)	This includes consideration of passenger and cargo transfers between new and existing facilities and the need for additional airfield facilities to serve the new runway.	Non-mandatory criteria for comparative analysis
Airside integration (operational)	This includes the ability of the new runway to integrate with existing airport facilities and operations and considerations of traffic flows, physical constraints, and availability of contingency.	Mandatory compliance required
Airspace and airport capacity	All options are faced with Pearl River Delta (PRD) airspace implications due to the addition of a third runway. These affect the operational feasibility and capacity gain potential of each option.	Non-mandatory criteria for comparative analysis
Construction issues	This includes the contaminated mud pits (CMPs), potential impacts on local shipping routes and other constraints to construction phase.	Non-mandatory criteria for comparative analysis
Environmental issues	This includes broad impacts due to aircraft noise, impacts to marine habitats, water quality and changes in hydrodynamics.	Non-mandatory criteria for comparative analysis
Surface access	This includes the ability to extend existing surface access facilities to serve the extended airport.	Non-mandatory criteria for comparative analysis
Topographical factors	This includes physical features (high ground) as well as local meteorological conditions.	Mandatory compliance required

Note 1: Criteria importance relates to the evaluation process in Stage 1 of the ‘Evaluation of the Third Runway Alignment Options’ section of this document.

3.3.2.3 These evaluation criteria were the main consideration in assessing and comparing individual alignment options during different stages of the evaluation process.

Evaluation of the Third Runway Alignment Options

3.3.2.4 The evaluation process comprised the following steps:

1. Stage 1 – 16 alignment options were subject to assessment against a set of mandatory compliance criteria (see mandatory criteria list specified in Table 3.1). The purpose was to review only the most important criteria (i.e. those that are fundamentally required to ensure safe and viable operation of the runway) to identify which alignments are compliant, and hence can be considered in Stage 2 of the evaluation. A relative comparison of non-mandatory criteria was also reviewed.

2. Stage 2 – comprised a more specific analysis of the operational characteristics of the preliminary shortlisted options to further verify the feasibility of each option. This stage produced a shortlist of options for further analysis in conjunction with different options for airport facility layouts.

3.3.3 Options for the Third Runway Alignment Stage 1 – Alignment Options

3.3.3.1 Stage 1 of the runway alignment options development focused on generic layouts to demonstrate the broadest range of possible runway alignments for initial assessment. This stage was based on information taken from the Airspace and Runway Capacity Study Phase 2 – Final Runway Options Report, a report undertaken in 2008 by the UK-based consultancy firm National Air Traffic Services (NATS) (1]. A total of 15 alignment options were developed, based on four runway concepts as summarised below:

Concept 1 – Third runway aligned at an angle to the existing runways (Options A and B);

Concept 2 - Third runway aligned parallel with the existing runways (Options C, D, E, F, G, and H);

Concept 3 - Third runway aligned parallel and significantly staggered from the existing runways (Options K, N, P, R and S); and

Concept 4 - Third runway located remotely from HKIA (Options J and M).

Option A

Option B

Option C

Option D

Option E

Option F

Option G

Option H

Option J

Option K

Option M

Option N

Option P

Option R

Option S

3.3.3.2 Stage 1 compared each of the 15 Options along with a sixteenth option (S extended option) and its variants against the mandatory criteria, taking into account the paramount ability to provide safe and viable arrival, departure and missed approach paths for safe and efficient operation of the runway. Table 3.2 summarises the results of the mandatory criteria assessment.

Table 3.2: Summary of Mandatory Criteria Compliance

Mandatory Requirements	Failed Options	Reason
Airside Integration (Operational)	A, B, C, J, M	These options provide either limited or no integration with the existing airport, thereby creating severe operational constraints
Topographical Factors (Operational Viability)	C, D, E, F, G, H, K, N, S	The runway associated with these options are either located too close to the mountains at Castle Peak or Lantau, or are too close to the existing runways, thereby compromising the viability of safe arrival / departure / missed approach procedures

3.3.3.3 The findings of the mandatory criteria analysis identified that only Option P, R and S extended are able to pass all the mandatory criteria for the safe and viable operation of the third runway. Additional variants of the S extended option were also found to provide compliant and viable solutions and were further developed as follows:

Option S Extended (Variant A and B)	Option S Extended (Variant C)

Option S Extended (Variant D)	Option S Extended (Variant E)

3.3.4 Options for the Third Runway Alignment Stage 2 – Shortlisted Options

3.3.4.1 For the three shortlisted options (Options P, R and S extended variants), a more detailed and in-depth analysis of operational compliance was undertaken in order to further verify option feasibility. This assessment was undertaken as part of the Airspace and Runway Capacity Study Phase 1b – Final Report by NATS in 2008 [4]. The main operational requirements considered included viable aircraft arrival and departure modes; emergency procedures; ground manoeuvring; and expansion potential of each option. Other operational requirements and considerations including airborne crossover issues; scheduling to maximise capacity; safeguarding for future flight routes; ability to implement (control) the three-runway airport; and interactions with adjacent airfields were also considered but were in general found to be affecting all options equally.

3.3.4.2 The following summarises findings from the operational compliance review:

¡ Option S extended (Variants A to E) were found not viable due to unresolvable flight movement issues associated with breakout manoeuvring². Option S extended was eliminated from further analysis, however, taking into account issues identified with previous variants, a viable revised Option S was introduced;

¡ Revised Option S however was assessed as having limited capacity potential due to constraints associated with dependent parallel approaches as well as being subject to some ground congestion concerns;

¡ Options P and R were generally found to have fewer operability issues and concerns compared to Option S.

2 Breakout manoeuvring refers to the emergency manoeuvring procedures that an aircraft needs to deploy when the parallel aircraft alongside it ‘blunders’, i.e. veers off its original flight path on decent.

3.3.4.3 As the operational review identified that runway alignment Options P, R and the revised Option S were all operationally feasible, these three runway alignments were adopted as the basis for evaluating a range of potential airport layout options.

3.4 Consideration of Alternatives for Airport Layout under a Three-Runway System

3.4.1 Summary of the Evaluation Process

3.4.1.1 The evaluation process for airport layout alternatives is shown in Chart 3-1 and comprised the following key steps:

Initial Stage: A broad evaluation of constructability and operational requirements to create a shortlist of airport layout options for detailed evaluation.

Final Stage: A detailed evaluation covering both non-environmental considerations and environmental considerations, leading to identification of a preferred option.

Chart 3-1: Evaluation process for three-runway system layout options

Starting Point

Initial Stage

Final Stage

3.4.1.2 Details of the airport layout evaluations are presented in the following subsections.

3.4.2 Initial Stage Airport Layout Options Evaluation

3.4.2.1 Based on the three shortlisted runway alignment options identified, a total of 18 airport layout options were developed, covering all possible permutations of apron, passenger terminal and concourse expansion locations. The 18 airport layout options considered four possible locations for the new passenger processing terminal (denoted as A, B, C, and D) and three possible locations for the aircraft aprons and passenger concourse areas (denoted as X, Y, and Z) as shown in Figure 3.1 (from MP2030).

Figure 3.1: Eighteen layout options

LEGEND

A, B, C & D show possible location of passenger processing terminal (where passengers are processed for check-in, Customs/Immigration/Quarantine and security screening)

X, Y & Z show the possible location of aircraft apron and passenger concourse area (where aircraft gates are located)

P, R & S denote spacing between the third and existing North Runways (i.e. far-spaced, normal-spaced and close-spaced) respectively

3.4.2.2 A qualitative review of the evaluation criteria (shown in Table 3.3) was then conducted by the MP2030 Study Consultant, to select better performing airport layout representative(s) from each of the three shortlisted runway alignment options (i.e. Option P, Option R and Option S) for carry forward to the detailed evaluation stage.

Table 3.3: Criteria for Initial Stage Airport Layout Options Evaluation

1.	AIRFIELD
	- Taxiing Time / Distance	Relative compared to each option
	- Runway Crossings	Relative compared to each option
	- Additional Control Tower	If needed for operations or for blocked lines of sight
	- Balance East / West	-
	- Cargo Connectivity	Proximity of stands / access to cargo
2.	TERMINAL
	- Passenger Connectivity	Minimum transfer time, APM complexity and capacity
	- Baggage Connectivity	Connection time / connectivity
	- Duplication of Facilities	Terminal processor, retail, surface access interchange, APM, etc.
	- Synergy with Airport Related Development (ARD)	Proximity
3.	SURFACE ACCESS
	- Road Access & Capacity	Extension of existing roads and capacity of new road
	- Airport Express Line (AEL)	Ability to extend existing line, or the need to create a secondary bifurcation
	- Cross Boundary Transport Facilities	Ability to serve cross boundary air / surface transit passengers via Coach, SkyPier and potentially the Hong Kong-Shenzhen Western Express Line (WEL)
4.	LONG-TERM CAPACITY / FLEXIBILITY
	- Strategic Consideration	Ability to meet demand growth beyond 2030
5.	CONSTRUCTIBILITY / COST
	- Runway / Taxiways	Runway / taxiway length or area
	- Construct over Mud Pits	Cost (and possible lead time)
	- Terminal Processor	Expansion / Extension of Terminal 1 (T1) / Terminal 2 (T2), or land formation for a new terminal
	- Surface Access – Road / Rail	Short extension of existing versus major line extensions / bifurcation
	- Total Land Formation Area	Land take-up
	- Operational Impact	-

Source: Airport Authority Hong Kong, Hong Kong International Airport, HKIA Master Plan 2030 Technical Report, July 2011, http://vps.hongkongairport.com/mp2030/TR_24May_Eng_Full.pdf

3.4.2.3 Four airport layout options were shortlisted as a result of the qualitative review as shown in Drawing Nos. MCL/P132/EIA/3-001 to MCL/P132/EIA/3-004. The main characteristics of the shortlisted options are summarised in Table 3.4.

Table 3.4: Summary of Shortlisted Options

Shortlisted Option	Summary
Option P (A + Y)	This option adopts the original P runway alignment from NATS with a remote satellite concourse to the northwest of the existing airport platform that is connected to T2. The principal objective of this option is to avoid construction over the CMPs and position passenger stands between a new widely spaced parallel runway and the existing North Runway.
Option R (A + X)	This option revises the original R runway alignment from NATS by shifting it as west as practicable up to the Mainland territorial waters boundary, with a remote linear satellite concourse north of the existing airport platform that is connected to T2. The principal objective of this option is to minimise construction over the CMPs and position passenger stands between a new widely spaced parallel runway and the existing North Runway.
Option R (A + Y)	This option revises the original R runway alignment from NATS by shifting it slightly to the east and north in order to fit in a remote satellite concourse to the north of the existing airport platform, assuming construction over the CMPs is feasible. The principal objective of this option is to position passenger stands between a new widely spaced parallel runway and the existing North Runway that is connected nearer to T2 as compared to Option R (A+X)
Option S (D + Z)	This option adopts the original S runway alignment from NATS with a new passenger terminal and concourse at the western end of the airport platform as the close spacing between the third runway and the existing North Runway would not allow for new facilities to be built in between. The principal objective of this option is to avoid construction over the CMPs and position a new passenger terminal and passenger stands to the west of existing airport platform. The length of the new runway is almost twice that of the P and R runway layout options to meet flight procedure and safety requirements in operating the new runway and the existing North Runway independently under a close-spaced arrangement.

3.4.2.4 The final stage of evaluation of the shortlisted airport layout options comprised an in-depth evaluation across key operational and functional parameters collectively called “Non-Environmental Evaluation” as well as an engineering feasibility and qualitative environmental assessment to identify an overall preferred option.

3.4.3 Final Stage of Non-Environmental Evaluation

3.4.3.1 Based on new land requirements for siting infrastructure required for the 3RS, the four shortlisted airport layout options could be generally categorised into two categories of options, namely “Northward Expansion” and “Westward Expansion”. An in-depth assessment of relative performance across key operational and functional parameters was undertaken for Northward and Westward expansion options.

Westward Expansion - Option S (D+Z)

¡ The third runway adopts a close-spaced separation from the existing North Runway, with new operational infrastructure required to support the 3RS to be located on land formation to the west of the existing airport island.

Northward Expansion - Option P (A + Y), Option R (A + X) and Option R (A + Y)

¡ The third runway adopts a wide-spaced separation from the existing North Runway, with additional operational infrastructure required to support the 3RS to be sited on land formation to the north of the existing airport island.

The outcome of the non-environmental relative performance evaluation of the two families of airport expansion options, as set out in MP2030, is recapped in Table 3.5.

Table 3.5: Comparative Performance Between Two Airport Expansion Options

Criteria	Westward Expansion	Northward Expansion
Airfield Efficiency	O	P
Passenger Convenience	O	P
Surface Access	O	P
Cargo Operations Efficiency	O	P

Note: where the criteria are met, this is denoted by ‘P ‘. Where the criteria is not met, this is denoted by ‘O ‘.

Source: Airport Authority Hong Kong, Hong Kong International Airport, HKIA Master Plan 2030 Technical Report, July 2011, http://vps.hongkongairport.com/mp2030/TR_24May_Eng_Full.pdf

3.4.3.2 A summary of the comparison between the Westward expansion option relative to the Northward expansion option is as follows:

Airfield Efficiency

a) For close-spaced parallel runways to be able to maintain independent segregated operations under ICAO guidelines, it is necessary to extend the third runway length from 3,800 m to 6,750 m, and the second runway (i.e. existing North Runway) length by 950 m to the west so that a 1,950 m stagger towards the arriving aircraft is available for both runway directions 07 and 25 (see Figure 3.2).

Figure 3.2: Illustration of runway extension required under a close-spaced parallel runway arrangement

This entails a substantial additional land formation area for the third runway as compared to the Northward expansion option, which has sufficient runway separation to adopt a normal length of 3,800 m for the third runway.

b) The separation of the close-spaced third runway from the first runway (i.e. existing South Runway) is also not sufficient to support independent parallel approaches. Only dependent staggered approaches can be accepted which will reduce the overall capacity of the 3RS to 97 movements per hour as compared to 102 under the Northward expansion option supporting independent parallel approaches (see Table 3.6).

Table 3.6: Runway Capacity of the Westward Expansion Option

Runway	Use	Capacity	Arrivals	Departures
07L/25R	Arrivals	31	31	─
07C/25C	Departures	35	─	35
07R/25L	Mixed	31	15.5	15.5
Total	─	97	46.5	50.5

Note: Values refer to the number of aircraft movements per hour.

Source: Airport Authority Hong Kong, Hong Kong International Airport, HKIA Master Plan 2030 Technical Report, July 2011, http://vps.hongkongairport.com/mp2030/TR_24May_Eng_Full.pdf

c) The close-spaced third runway does not allow room for locating the additional passenger aircraft stands requirement adjacent to the third runway as compared to the Northward expansion option. Aircraft arriving on the third runway need to taxi across the existing airfield to the apron on the western land formation or Midfield area, creating longer taxiing time, increased ground congestion and delays, and more runway crossings than the Northward expansion option which will likely further reduce runway capacity to less than 97 movements per hour (see Figure 3.3).

Figure 3.3: Aircraft ground movements congestion under the Westward expansion options

Passenger Convenience

3.4.3.3 The Westward expansion option for developing a new passenger processing terminal (Terminal 3 or T3) and a new passenger concourse at the western side of the airport island would require passengers to make an early decision when approaching T1, T2 or T3 (i.e. boarding public transport routes bound for T1 / T2 versus a separate route bound for T3). Due to the large distance separation between T3 and T1/ T2, an accommodation for route recovery would be require in the event when passengers proceed to the wrong terminal. There would also be added inconvenience and longer travelling distances for inter-terminal transfers and inter-modal connections with Hong Kong - Zhuhai - Macao Bridge (HZMB) (see Figure 3.4) and SkyPier located on the eastern side of the airport island.

Figure 3.4: Passenger inconvenience of the Westward expansion options

3.4.3.4 The Northward expansion option for the development of the new passenger concourses would lessen passenger inconvenience associated with the Westward expansion option. The Northward expansion option would have passengers from the new concourses processed through the existing passenger terminal zone via expansion of the existing T2 into a full-fledged departures and arrivals terminal with dedicated underground APM and BHS linked to the new passenger concourses.

Surface Access Quality

3.4.3.5 The Westward expansion option cannot share the existing fully integrated ground transportation facilities already established at the eastern side of the airport island, particularly the direct connections to the AEL station to downtown and the APM station to the SkyPier ferry terminal and future Hong Kong Boundary Crossing Facilities (HKBCF) (see Figure 3.5). The split passenger terminal zones associated with the Westward expansion option would inevitably lead to inferior surface access quality compared to that of a centralised passenger processing terminal zone that is provided for under the Northward expansion option.

Figure 3.5: AEL and SkyPier ferry terminal

App3_Fig5a

App3_Fig5b

Cargo Operations Efficiency

3.4.3.6 Given that cargo transport is time-critical, it is preferred to locate the new freighter stands at the Midfield to allow shorter towing distances between the new freighter stands and the cargo terminals in the southern cargo precinct (see Figure 3.6). This could only be achieved under the Northward expansion option but not the Westward expansion option which needs to assign the entire Midfield area for new passenger concourses development to minimise taxiing distance to/from passenger aircraft stands.

Figure 3.6: Preferred location of future cargo apron and freighter stands

3.4.3.7 The non-environmental evaluation has identified that “Northward Expansion” is preferred to “Westward Expansion” in enlarging the footprint of HKIA into a 3RS. The outcome of the non-environmental evaluation was supported by the “Engineering Feasibility and Environmental Assessment Study for Airport Master Plan 2030, Comparative Environmental Assessment” with Option R (A + Y) within the Northward expansion family options also being identified as the best environmental performing option, which was consequently adopted by MP2030 for development into the recommended layout for the 3RS scenario.

3.4.4 Environmental Evaluation under MP2030

3.4.4.1 The environmental evaluation was undertaken in parallel with the non-environmental evaluation and forms part of the assessments in the Engineering Feasibility and Environmental Assessment Study for Airport Master Plan 2030, Comparative Environmental Assessment Report completed in 2009 by Mott MacDonald [5].

Early Consideration of Environmental Implications associated with Engineering Design

3.4.4.2 The main potential environmental implications of a third runway result primarily from both the physical location / footprint of the airport expansion and construction methods that are developed for land formation. Thus, engineering design considerations and requirements do have significant impacts on the environmental performance of different airport layout options. Table 3.7 shows the major land formation characteristics associated with each shortlisted option.

Table 3.7: Summary of the Major Characteristics of Each Shortlisted Option [5]

Major Characteristics	P (A + Y)	R (A + X)	R (A + Y)	S (D + Z)
Total land formation area	743 ha	790 ha	827 ha	819 ha
Encroachment to CMPs	3 ha	32 ha	200 ha	Nil
Seawall length	18 km	18 km	11 km	15 km
Minimum clearance to Chinese Territorial Waters boundary	150 m	100 m	1 km	1 km
Minimum clearance to Sha Chau and Lung Kwu Chau Marine Park	350 m	1 km	1 km	2 km

Identification of the Key Environmental Differentiators for Comparison of Options

3.4.4.3 A set of environmental performance indicators was developed to facilitate a simple ‘option to option’ comparison of the key anticipated environmental impacts, at construction and operation stages. The comparison exercise was not intended to be a thorough “quantitative” assessment of environmental impacts and their acceptability, rather, a simple differentiation of the shortlisted options based on “larger” or “smaller” impact in the indicator area for each of the options – allowing for a simple ranking of options³. The key environmental differentiators adopted for shortlisted airport layout options evaluation are presented in Table 3.8.

3 Environmental differentiators are those environmental parameters assessed as exhibiting potential variability between options. Certain environmental parameters, such as construction phase air quality impact, were not included as they were assessed as exhibiting no significant variability between options.

Table 3.8: Summary of Key Environmental Differentiators During Construction and Operation Phase [5]

Key Environmental Differentiators	Construction Phase	Operation Phase
Air Quality	N/A	§ Airport operational efficiency¹
Chinese White Dolphins (CWD)	§ Disturbance to CWD feeding grounds § Disturbance to dolphin calves	§ Permanent loss of feeding grounds § Proximity of northern site boundary to Sha Chau and Lung Kwu Chau Marine Park (and associated risk of CWD injury due to collision with vessels)
Fisheries	§ Disturbance to fisheries production § Disturbance to fishing operation § Loss in fisheries value due to construction	§ Permanent loss in fisheries production § Habitat loss § Fishing operation § Fisheries value § Impact of Hong Kong International Airport Approach Area (HKIAAA) on fisheries operation
Marine Ecology	§ Disturbance to horseshoe crab nursery grounds § Impact of increased suspended solids (SS) concentrations on marine ecological sensitive receivers § Disturbance to existing coral and artificial reefs	§ Loss of intertidal habitats § Loss of soft-bottom habitats § Loss of coral communities
Noise	§ Cumulative impact due to concurrent projects on noise sensitive receivers (NSRs)	§ No. of dwellings situated within a preliminary noise exposure forecast (NEF) 25 contour projection
Visual	§ Disturbance to visually sensitive receivers (VSRs) at Sha Lo Wan and Tung Chung	§ Disturbance to VSRs at Sha Lo Wan and Tung Chung
Waste	§ Quantity of dredged sediment (outside of CMPs)	N/A
Water Quality and Hydrodynamics	§ Increase in SS concentrations at water sensitive receivers § Release of sediment fines and contaminants during ground improvement at CMPs	§ Change in tidal flow § Erosion of seabed § Change in flushing capacity at the existing airport channel § Potential water quality impact from a poorly flushed embayment

Note 1: This provides a measure of the potential operation phase air quality as it relates to aircraft emissions.

3.4.4.4 Other environmental parameters, such as construction phase air quality impact, hazard to life, terrestrial ecology, landscape and cultural heritage, were identified as not being significant differentiators that could be used in the options evaluation and hence were excluded from the options selection process.

Environmental Evaluation of the Shortlisted Options – Benefits and Dis-Benefits

3.4.4.5 For the differentiators identified under each key environmental aspect, relative environmental performance was summarised into an equivalent relative ranking for each shortlisted option. The ranking evaluation was made based on best professional judgement of the information available at the time of evaluation, giving more focus on key long-term and irreversible environmental impacts. A summary of findings from the comparative environmental assessment is presented in Table 3.9.

Key Environmental Differentiators	Option 1 – P (A + Y)	Option 2 – R (A + X)	Option 3 – R (A + Y)	Option 4 – S (D + Z)	Preferred Option
Air Quality	· No defining benefit compared to other options	· No defining benefit compared to other options	· No defining benefit compared to other options	· No defining benefit compared to other options	· No defining benefit compared to other options	· No defining benefit compared to other options	· No defining benefit compared to other options	· Generally associated with less operational efficiency compared to other options.	No definitive option is preferred.
CWD	· Affect a smaller area associated with CWD calves sighting, therefore has lower potential to adversely impact CWD breeding grounds. · Smallest area of permanent habitat loss and a smaller number of CWDs potentially affected.	· Affect a larger area associated with CWDs engaged in socialising activities, therefore has higher potential to adversely affect CWD social activities (along with Option 2). · Located closest to the Sha Chau and Lung Kwu Chau (SCLKC) Marine Park, therefore has higher potential disturbance to CWD protected area. · Evaluated to have higher potential severity of impacts to CWDs during operation phase	· Affect a smaller area associated with CWDs engaged in feeding activities, therefore has lower potential for disturbance to feeding grounds (along with Option 3).	· Affect a larger area associated with CWDs engaged in socialising activities, therefore has higher potential to adversely affect CWD social activities (along with Option 1).	· Affect a smaller area associated with CWDs engaged in feeding activities, therefore has lower potential for disturbance to feeding grounds (along with Option 2).	· Largest area of habitat loss (but the lost habitat was less used by CWDs)	· Affect a smaller area associated with CWDs engaged in socialising activities, therefore has lower potential to adversely affect CWD social activities. · Located furthest from the SCLKC Marine Park, therefore has lower potential disturbance to CWD protected area.	· Affect a larger area associated with CWD calves sighting, therefore has higher potential to adversely impact CWD breeding grounds. · Affect a larger area associated with CWDs engaged in feeding activities, therefore has higher potential for disturbance to feeding grounds. · Larger area of permanent habitat loss and number of CWDs potentially affected. · Evaluated to have higher potential severity of impacts to CWDs during both construction and operation phase.	Option 3 – generally associated with less CWD impacts compared to the other options.
Fisheries	· Smallest area of potential fisheries habitat loss	· Future HKIAAA may extend outside Hong Kong marine waters boundary and would lie closest to the SCLKC Marine Park, which may discourage fishing activities in this area.	· No defining benefit compared to other options	· Future HKIAAA may extend outside Hong Kong marine waters boundary and make access to the high fisheries production areas at northwest Lantau difficult for fishermen.	· Relatively less potential impact to fisheries activities due to wider separation between the new HKIAAA, SCLKC Marine Park and Hong Kong marine waters boundary.	· Largest area of potential fisheries habitat loss	· No defining benefit compared to other options	· Future HKIAAA may discourage fishermen from fishing at northwest Lantau.	Option 3 – generally considered to have marginally less impact on fisheries activities compared to other options.
Marine Ecology	· No defining benefit compared to other options	· Located closest to the SCLKC Marine Park, therefore is associated with higher potential impact on the Marine Park due to SS release during construction phase.	· No defining benefit compared to other options	· No defining dis-benefit compared to other options	· Located furthest from the Sha Lo Wan horseshoe crab habitat, therefore is associated with less potential impact on the habitat due to SS release during construction phase.	· No defining dis-benefit compared to other options	· Located furthest from the SCLKC Marine Park, therefore is associated with less potential impact on the Marine Park due to SS release during construction phase.	· Located closest to the Sha Lo Wan horseshoe crab habitat, therefore is associated with higher potential impact due to SS release during construction phase.	Option 3 – associated with less dis-benefits compared to Options 1 and 4, and more benefits compared to Option 2.
Noise	· Potentially associated with less aircraft noise impacts to NSRs (due to larger runway separation distance).	· No defining dis-benefit compared to other options	· No defining benefit compared to other options	· No defining dis-benefit compared to other options	· Further separation distances from NSRs along North Lantau. · Potentially associated with less aircraft noise impacts to NSRs (due to larger runway separation distance).	· No defining dis-benefit compared to other options	· No defining benefit compared to other options	· Shorter separation distances from NSRs along North Lantau. · Potentially associated with more aircraft noise impacts to NSRs	Option 3 – generally associated with more benefits compared to other options.
Landscape & Visual	· Relatively further from VSRs at Tung Chung	· Relatively closer to VSRs at Sha Lo Wan	· Relatively further from VSRs at Tung Chung	· Relatively closer to VSRs at Sha Lo Wan	· Generally further from VSRs at both Sha Lo Wan and Tung Chung	· No defining dis-benefit compared to other options	· No defining benefit compared to other options	· Closest to VSRs at Sha Lo Wan	Option 3 – generally associated with less dis-benefits compared to other options.
Water Quality and Hydrodynamics	· No defining benefit compared to other options	· Relatively higher SS concentration at some water sensitive receivers (WSRs) compared to other options. · Re-deposition of sediment on corals is highest compared to other options · Area of stagnant water produced due to eastern embayment · Highest erosion potential around the new runway	· Lower SS concentration at some WSRs compared to other options.	· Area of stagnant water produced due to eastern embayment	· Generally lower SS concentration at WSRs compared to other options. · Not associated with significant flow stagnation.	· No defining dis-benefit compared to other options	· Relatively lower SS concentration at some WSRs compared to other options. · Not associated with significant flow stagnation.	· Relatively higher SS concentration at some WSRs compared to other options. · Reduce flushing capacity at Airport Channel · Higher siltation potential at Airport Channel than other options	Option 3 – generally associated with less water quality impacts compared to the other options.
Cultural Heritage	Not a key environmental differentiator as all options would have similar potential marine archaeological impact, and no direct impacts to terrestrial cultural heritage.
Hazard to Human Life	Not a key environmental differentiator as all options would have similar potential hazard to human life impacts associated with diversion of submarine fuel pipeline, extension of fuel hydrant system, and dangerous goods storage (diesel, gasoline and liquid petroleum gas).
Terrestrial Ecology	Not a key environmental differentiator as all options would have similar impacts (mainly indirect impacts) to terrestrial ecology.
Waste*	· Lowest quantity of dredged sediment (outside CMP area)	· No defining dis-benefit compared to other options	· No defining benefit compared to other options	· No defining dis-benefit compared to other options	· Lowest quantity of dredged sediment requiring disposal (outside CMP area)	· No defining dis-benefit compared to other options	· No defining benefit compared to other options	· Highest quantity of dredged sediment requiring disposal (outside CMP area)	No longer applicable

Option	Possible Refinement	Environmental Benefits / Dis-benefits of Refinement
Option 1 – P (A + Y)	Maximise the distance from the SCLKC Marine Park	This seeks to increase the distance from the SCLKC Marine Park from 350 m to 700 m by reducing the northern extent of land formation. However, this option would still be closer to the Marine Park than the other options, hence no significant change to the environmental impact levels and relative ranking is anticipated.
Reducing the extent of land formation at the western side of the existing North Runway	The possibility of reducing the extent of land formation at the western side would lead to improvements in terms of: § reduced disturbance to CWD feeding grounds and calves; § reduced loss of soft-bottom habitats and coral communities; and § reduced quantity of dredged sediment However, the creation of a poorly flushed embayment would increase the potential water quality and hydrodynamic impact for this option.
Option 2 – R (A + X)	Reducing the extent of land formation and use of decking for the taxiway	This seeks to significantly reduce the extent of land formation and eliminate the poorly flushed embayment by using decking instead of land formation for the taxiway. Improvements include: § improved flushing capacity; § reduced disturbance to fisheries production; § reduced loss of intertidal habitats and soft-bottom habitats; § reduced impact of increased SS on marine ecological sensitive receivers; and § reduced quantity of dredged sediment. However, as piling would be required for construction of the decking, the impact on CWDs would increase.
Eliminating the embayed area	This seeks to possibly eliminate the embayed area by shifting the proposed runway to the south. This would lead to improvements in terms of: § reduced impact to CWDs due to greater separation distance from the Marine Park and less habitat loss; and § reduced embayment areas.
Option 3 – R (A + Y)	Reducing the extent of land formation at the western side	The possibility of reducing the extent of land formation at the western side would lead to improvements in terms of: § reduced permanent loss of CWD feeding grounds; § reduced impact on fisheries production and operation; § reduced loss of intertidal, soft-bottom and coral communities / habitats; § less disturbance to horseshoe crab nursery grounds; and § reduced quantity of dredged sediment.
Shifting the proposed runway to the east	This seeks to give a more streamlined footprint from a hydrodynamic point of view, however, the findings of the hydrodynamic assessment found that no significant change in tidal flow was predicted, and no significant improvement in terms of erosion of the seabed was predicted. Consequently, no additional environmental benefit was identified with this refinement.
Option 4 – S (D + Z)	Eliminating the embayed area	This seeks to create a more streamlined footprint by trimming the eastern end of the proposed runway to eliminate the embayed area. This would lead to improvements in terms of: § removal of the poorly flushed embayment; § reduced impact to CWDs by reducing habitat loss and disturbance to feeding grounds and dolphin calves; § reduced habitat loss and impact on fisheries production; § reduced loss of soft-bottom habitats and reduced disturbance to artificial reef and impact from SS; and § reduced quantity of dredged sediment.
Reducing the extent of land formation by use of decking for taxiway near the airport sea channel	This refinement seeks to minimise hydrodynamic impact by eliminating about 24 ha of land formation by using decking for the taxiway. This would lead to improvements in terms of: § reduced impact on the flushing capacity at the channel; § reduced loss of soft-bottom habitats and less disturbance to horseshoe crab nursery grounds; and § reduced quantity of dredged sediment. However, as piling would be required for construction of the decking, the impact on CWDs would increase.
Trimming of headland around Sha Lo Wan	This seeks to improve the flushing capacity at the airport sea channel, but would result in permanent loss of habitats for horseshoe crabs.

	Option 1 BASELINE	Option 2 TRIPLE CONCOURSES	Option 3 Y-Y	Option 4 TWIN - STAR	Option 5 TWIN - TRIANGLE	Option 6 HORSESHOE	Preferred Option
General Description
	Based on the existing T1, the Baseline scheme adopts the same T1 concourse width with the baggage hall located underground.	Based on the MP2030 layout. This scheme adopts three separate concourses with the baggage hall located underground.	Single concourse layout derived from the Baseline scheme, with wider concourse to accommodate baggage hall at apron level.	Based on the Baseline scheme but with an expanded area within the concourse to create additional reserve areas and accommodate baggage hall at apron level.	Similar to the Twin Star scheme with larger reserved area at each concourse for future expansion and accommodate baggage hall at apron level.	This scheme represents the ultimate shape that provides the largest area to perimeter ratio. The aim of this configuration is to maximise the area available for reserve land for future expansion and accommodate baggage hall at apron level.	N/A
Capacity	62 contact stands 47 remote stands	60 contact stands 40 remote stands	60 contact stands 45 remote stands	62 contact stands 36 remote stands	62 contact stands 42 remote stands	54 contact stands 25 remote stands	Option 1 or 3
Operational Efficiency	This option has high taxiway efficiency and user friendliness with easy route recovery and transfers between the concourse, but has limited space for passenger / commercial facilities.	This option presents a risk of taxiing congestion and increased airside road journey times between the two farthest nodes, though it has the benefit of providing taxi-lane alternatives and shorter taxiing distance for certain stands. In terms of terminal operations, more concourses complicate passenger wayfinding and the additional facilities required (e.g. three APM stations and separate baggage systems) would increase both journey / transit times and operational costs. This option is the least efficient overall.	This option provides greater operational efficiency and user friendliness with easy route recovery and transfers between the concourse and better space allocation to accommodate different passenger / commercial facilities. Baggage operational efficiency is generally higher than other configurations.	Similar efficiency to the Baseline scheme and provides shorter taxiing distance for certain stands, but concourse operational efficiency is affected by the split concourses, which necessitates some duplication of facilities.	Similar efficiency to the Baseline scheme, but concourse operational efficiency is affected by the split concourses, which necessitates some duplication of facilities.	This option has poor taxiway efficiency due to uni-directional taxi-lane layout. Concourse operational efficiency is also affected by the split and uneven concourses.	Option 3
Phasing / Flexibility	Single concourse enables consolidation of terminal facilities and provides more flexibility for phased commissioning. Limited opportunity for creating outdoor spaces. No reserve area for future expansion.	Based on capacity requirements, at least two of the three buildings will need to be commissioned in Phase 1. Limited opportunity for creating outdoor spaces. No reserve area for future expansion.	Single concourse enables consolidation of terminal facilities and provides more flexibility for phased commissioning. Opportunities available for creating outdoor spaces which can be safeguarded for future expansion.	Large central concourse area allows for future expansion flexibility, but less capacity for phased commissioning of facilities.	Large central concourse area allows for future expansion flexibility, but less capacity for phased commissioning of facilities.	Large central concourse area allows for future expansion flexibility, but less capacity for phased commissioning of facilities.	Option 3
Programme and Costs	No significant difference in construction programme compared to other options.	No significant difference in construction programme compared to other options. Higher construction cost due to multiple terminal buildings and associated APM / BHS facilities.	No significant difference in construction programme compared to other options. Cost for the wider concourse is offset by the bag hall at apron level.	No significant difference in construction programme compared to other options. Generally higher construction cost due to larger building area.	No significant difference in construction programme compared to other options. Generally higher construction cost due to larger building area.	No significant difference in construction programme compared to other options. Generally higher construction cost due to larger building area.	Option 1 or 3
Environmental	Requires excavation into CMPs	Requires excavation into CMPs	Avoids the need for excavation into CMPs	Avoids the need for excavation into CMPs	Avoids the need for excavation into CMPs	Avoids the need for excavation into CMPs	Option 3 to 6

Environmental Benefits / Dis-Benefits

3.5.2.2 In general, the only environmentally significant consideration between different TRC configuration options is whether excavation into the CMPs is required or not, which would affect the quantities of excavated marine sediment. Apart from this aspect, the various TRC options do not have a significant bearing on the environmental acceptability of the project, as there are no other significant environmental differences among the TRC options. Based on this environmental consideration, Options 3 to 6 would be equally more preferable from an environmental perspective when compared to Options 1 and 2.

3.5.2.3 Given that there are limited environmental differences between options, the decision for selection of the preferred scenario for TRC configuration is thus dominated by capacity and operational considerations. However, in selecting the TRC option that provides the best overall operational and efficiency gains, there are inherent environmental benefits resulting from these efficiency gains, such as reduced raw materials requirement during construction phase, and reduced building energy consumption during operation phase. Similar ‘environmental dis-benefits’ would apply to options that are less operationally efficient.

Selection of Preferred Scenario – Third Runway Concourse

3.5.2.4 Based on the comparison of TRC options as shown in Table 3.11, the single concourse Y-Y configuration (Option 3) has been identified and selected as the preferred scenario for the 3RS. In a similar manner to the existing T1, the single concourse configuration is considered to offer important operational benefits including:

¡ Ground vehicle movements not impeded by having to cross cut through taxi lane;

¡ Single baggage hall at apron level to allow efficient baggage ramp handling and reducing tug and dolly travel distances;

¡ Flexibility to allocate aircraft to stands and increased efficiency in terms of staffing / resource allocation;

¡ Requires fewer ground service equipment (GSE) to service aircraft as vehicles do not need to be allocated to separate terminals;

¡ Can be built incrementally, which provides flexibility in planning and phasing; and

¡ Flexibility in terms of catering to future demands, i.e. airline allocation.

3.5.2.5 Accordingly, the preferred scenario would provide environmental benefits in terms of:

¡ Avoidance of excavation into CMPs and less waste generated due to excavation;

¡ Reduced GSE emissions (due to few GSE and more efficient vehicle movements); and

¡ Less building energy demand (due to improved operational efficiency).

3.5.3 Terminal 2 Expansion and the associated Road Network Options

3.5.3.1 As an outcome of the airport layout options assessment, the existing T2 will be partly demolished, modified extensively and expanded to become a full-fledged passenger processing terminal to serve the new third runway. Two options for T2 expansion and associated road network were considered and evaluated. Table 3.12 presents a summary of these options and the road network options are shown in Drawing No. MCL/P132/EIA/3-008.

Table 3.12: Summary of Descriptions and Construction Methods for Terminal 2 Expansion and the Associated Road Networks Options

Parameters	Terminal Concept A	Terminal Concept F
General Design	Terminal: This option assumes that T2 has to be partially shut down and modified in order to expand to the new terminal layout, while keeping operation in T2 throughout the entire construction period. Facilities of the expanded T2 include the main building composed of Departures Hall, Check-in Hall, Departures Kerb, Baggage Claim Hall, Meeters and Greeters Hall, Custom, Immigration and Quarantine (CIQ) Area, Baggage Handling Area, APM Interchange Station and BHS North Basement, and the North and South Annex Buildings accommodating coach staging, car parking, loading and unloading, and limousine lounge provisions. As the Departures Kerb is positioned on the eastern side of the main building, bi-directional passenger flows from new Departures Kerb and existing AEL Station to Check-in Hall at Departures Level are anticipated. Associated Road Networks Option A1: The departures kerb of this option is located at the eastern side of the terminal. This road option provides a longer length of departures kerb comparing to Option A2 below. A slip road linking the northern elevated road to existing Airport Road is proposed for recirculation to T1 departures kerb. Slip roads connecting to North Lantau Highway (NLH)/Airport Road and HKBCF are also allocated at the south of the CLP substation. Based on this configuration, the proposed northern elevated road and realigned SkyCity Road will encroach onto the North Commercial District (NCD) development area and the AsiaWorld Expo (AWE) Phase 2 Expansion site. Associated Road Networks Option A2: The departures kerb of this option is located at the eastern side of the terminal. To minimise the encroachment into AWE Phase 2 Expansion Area, a “ring road” option is developed with the elevated road for egress traffic from the T2 departures kerb to circulate around the NCD development site along its northern and eastern perimeter and connect back to Airport Road southbound south of the airport south interchange. Separate slip roads for re-circulation / route recovery to T2 departures kerb and connection to HKBCF are branched off from the elevated road at the eastern perimeter. The length of the departures kerb in this option is shorter than Option A1 by about 60 m. This road option does not have major impact to existing building structures but will confine the NCD development within the boundary of the elevated ‘ring’ roads.	Terminal: This option assumes that the operation in T2 will be suspended during the entire construction period as T2 has to be shut down and substantially modified in order to add a new floor, raise the roof, build the new Departures Road on the western side of the main building, and increase pile loading capacity etc. Facilities of the expanded T2 include the main building composed of Departures Hall, Check-in Hall, Departures Kerb, Baggage Claim Hall, Meeters and Greeters Hall, CIQ Area, Baggage Handling Area, APM Interchange Station and BHS North Basement, and the North and South Annex Buildings accommodating coach staging, car parking, loading and unloading, and limousine lounge provisions. As the Departures Kerb is positioned on the western side of the main building, unidirectional passenger flows from new Departures Kerb and existing AEL Station to Check-in Hall at Departures Level can be achieved. Associated Road Networks Option F: This option assumes the location of the departures kerb to be positioned on the western side of the building immediately east of the existing HKIA Tower and Airport World Trade Centre (AWTC), which will require demolition of Level 5 slab of the existing T2 building. Under this option, two elevated roads connected to northern and southern ends of the proposed departures kerb were proposed for vehicle re-circulation to T2 departures kerb. The southern recirculation ramp and the approach ramp linking to HKBCF will route along the western and southern sides of existing CLP Primary Substation. The length of departures kerb in this option is similar to Option A1. With departures kerb on the western side of the terminal building, unidirectional check-in experience for departures passengers, similar to T1, can be achieved. This road network option can avoid major encroachment on adjacent commercial development sites. In comparison with Options A1 and A2, Option F is considered to be a better option in terms of terminal planning and has less impact on future adjacent commercial developments.
Construction Method	Terminal: Phased construction starting with the southern section and the new build areas before commencing construction of the northern section after re-opening the new southern section. Basement walls will be formed using diaphragm walls and pre-bored H-piles / bored piles will be adopted for foundation system of the main building and annex buildings. A combination of in-situ and precast concrete construction will be adopted for the main levels, while the roof structure for the new build area will be constructed by erection of trusses followed by prefabrication of roof panels using pre-assembled jigs.	Terminal: Generally similar to that of Concept A, except the operation in T2 will be suspended during the entire construction period.
Environmental Considerations	Under Concept A, as part of the terminal is retained to keep continuous operation during construction of T2 expansion, some noise, dust and air quality impacts on passengers and operation staff are inevitable and impact to terminal operation is anticipated as daily operation will be carried out in the same building as the construction site for more than 5 years. This option requires less construction materials for the permanent works. However, as part of the terminal is retained during construction while keeping T2 in operation, more temporary works are required during construction to ensure safe and pleasant environment for passengers during construction. Hereby, the amount of overall Construction and Demolition (C&D) waste would be slightly less than Concept F. Construction period is similar and hence the duration of potential air and noise impacts is similar to Concept F. Limited capability in reducing potential environmental footprint, such as waste reduction and energy saving, due to constraints imposed by existing building structures on technology leverage and infrastructure to improve long-term sustainability.	Fewer disturbances to T2 passengers and operation staff in respect of noise and air with check-in and daily operation related activities to be redirected away from the construction site in T2. For permanent works, this option requires more construction materials and will generate more C&D waste compared to Concept A, as a larger part of the terminal needs to be demolished and re-constructed. However, the amount of temporary works would be significantly less than Concept A. Hereby, the amount of overall C&D waste would be slightly more than Concept A. Construction period is similar and hence the duration of potential air and noise impacts is similar to Concept A. Excellent capability in reducing potential environmental footprint as facilitated by better flexibility and capacity to introduce environmental-friendly infrastructure and technology to improve long-term sustainability, such as energy saving associated with building envelop in lowering the overall thermal transfer value.
Impact to Existing Operations	Concept A involves phased delivery of the building extension in such a way as to permit the existing T2 building to continue to function and meet the operational demand throughout the construction period, with minimal impact on the existing T1.	With additional T1 terminal facilities under planning, operational demand throughout the construction period will be maintained.
Programming	Total duration approx. 87 months	Total duration approx. 87 months

Environmental Benefits / Dis-Benefits – Terminal 2 Expansions

3.5.3.2 Based on the environmental considerations described in Table 3.12, Concept A would be slightly less preferable than Concept F in terms of construction dust and noise impacts to nearby sensitive receivers, passengers and operations. While Concept F would generate slightly more C&D waste than Concept A, some of this can be reused on-site as part of the land formation activities. Overall, the environmental performance of Concept F is considered to be slightly better than Concept A.

3.5.3.3 It should be noted that in general, neither of the T2 expansion options have a significant bearing over the other on the environmental acceptability of the project, as both options would create a certain amount of construction-related environmental disturbance. The deciding factor for selection of the preferred scenario for T2 configuration would thus be focused more on operational considerations. As with selection of the TRC option, the selection of the T2 option that provides the best overall operational and efficiency gains would also provide some inherent environmental benefits in the long term (e.g. a more energy efficient terminal building would reduce energy and water demand during operation phase). Similar ‘environmental dis-benefits’ would apply to the option that is less operationally efficient. Thus it can be deduced that the preferred option for T2 expansion on the ground of better operational efficiency would also be a favourable option from an environmental perspective.

Environmental Benefit / Dis-Benefit – Terminal 2 Road Network Options

3.5.3.4 Generally, there is very little difference in the environmental performance among the different road network options. From an environmental quality perspective, a shorter alignment would reduce potential road traffic emissions, require less construction materials and potentially produce less construction waste, while an alignment that is located furthest away from sensitive receivers would reduce air quality, noise and visual impacts to these sensitive receivers.

3.5.3.5 Based on these considerations, Options A1 and A2 would be the least preferable, as it has the longer road alignment and will encircle the future adjacent commercial development, thereby potentially affecting more sensitive receivers. Option F would be slightly more preferable as it does not encroach onto the adjacent commercial development site and AsiaWorld-Expo Phase 2 expansion areas, and the alignment of Option F is very similar to that of the existing road network surrounding T2, hence the potential environmental impacts of this option are more confined within the same areas of the existing road network. Thus, Option F is identified as the option with the least environmental impact on and constraints to other planned developments on airport island.

Selection of Preferred Scenario – T2 Expansion and associated Road Network

3.5.3.6 Based on the comparison of T2 expansion and associated road network options as described above, Concept F and the associated Road Network Option F has been identified and selected as the preferred scenario for the T2 expansion. Concept F is considered to offer important operational benefits including:

¡ Unidirectional passenger flow from AEL station / departures kerb to the Check-In Hall, similar to T1;

¡ Entire Check-in Hall is under a new roof design with high headroom comparable to T1;

¡ More spacious and airy ‘Meeters and Greeters’ Hall and Baggage Reclaim Hall; and

¡ No encroachment on AWE Phase 2 expansion area and minor encroachment on the NCD development site with Road Network Option F.

3.5.3.7 Accordingly, the preferred scenario would provide environmental benefits in terms of:

¡ Road Network Option F is identified as the option with the least environmental impact;

¡ Less disturbance to T2 passengers and operation staff in respect of dust and noise, with check-in and daily operation related activities to be redirected away from the construction site in T2;

¡ More potential to improve long-term sustainability since Concept F has excellent capability in reducing potential environmental footprint as facilitated by better flexibility and capacity to introduce environmental-friendly infrastructure and technology; and

¡ Less building energy demand (due to improved operational efficiency).

3.5.4 Preferred Runway and Airport Layout

3.5.4.1 Based on the preferred runway and airport layout option and the further refinements including the preferred TRC option, the preferred master airport layout plan adopted for initial scheme design and environmental impact assessment is shown in Drawing No. MCL/P132/EIA/3-006. The major components of the new land formation comprise a new third runway along the northern boundary, a new passenger concourse, two designated areas set aside for airfield support facilities (the western supporting area and eastern supporting area, located on either side of the passenger concourse development), and expansion of the areas around the existing North Runway.

3.5.4.2 On the existing airport island, the major areas and facilities which need to be modified to integrate with the new third runway facilities include expansion of T2, an underground APM depot, modification of landside road networks, construction of new airside tunnels, expansion of Midfield aprons and expansion / extension of various infrastructure and utilities.

3.6 Consideration of Alternative Construction Methods for Land Formation

3.6.1 Land Formation

3.6.1.1 To provide the land required for the third runway development, a range of possible land formation methods which may support the new third runway and associated infrastructure were reviewed. These land formation options include:

¡ Conventional dredging/non-dredging

¡ Piled Structures

¡ Semi-buoyant Construction

¡ Floating Structures

3.6.1.2 A summary of the land formation options is described in Table 3.13.

Table 3.13: Summary of Land Formation Methods

Process / Technology	Operating Principles	General Evaluation	Environmental Benefit / Dis-benefit
Conventional dredging / non-dredging	This involves construction of conventional land formation retained by seawalls, with dredging/non-dredging as the method to enable improvement of the ground that underlies the land formation and seawalls	This type of conventional land formation has a proven track record for application in Hong Kong. The non-dredge method has been recently successfully applied in Hong Kong and is also considered to be a reliable and cost-effective approach for large-scale land formation.	Ground improvement works via dredging and disposal of marine sediment will generate substantial sediment plumes with its associated adverse impacts to water quality and marine ecology, as well as large volumes of waste needing off-site disposal. Furthermore, dredging method would not be permitted within the CMP area. Due to the environmental impacts associated with this option, conventional dredging for land formation has been discouraged by the Hong Kong Government. Conversely, non-dredge methods can substantially reduce the environmental impacts compared with the conventional dredging method. Disturbance of the CMPs would be minimised by adoption of ground improvement via in-situ soil / cement mixing methods (i.e. Deep Cement Mixing).
Piled Structures	A structural platform supported by installation of conventional piles	This method has been successfully trialled as part of the land formation for similar projects overseas. However, comparing the long-term maintenance requirements of the piled structures, this option is not considered to be cost-effective compared to other options.	This method has the benefit of reducing the permanent changes to hydrodynamics that would result from the new land formation. However, application of marine piling has the potential to directly disturb the CMPs (whereby some of the material will be excavated and will require disposal) and widespread application would also generate substantial underwater noise impacts.
Semi-buoyant Construction	Semi-buoyant construction involves using light-weight fill such as expanded polystyrene (EPS) blocks	The use of light-weight fill has been considered within the context of a conventional land formation and is a variation on the type of fill which could be used, but previous applications elsewhere were generally small scale and within an onshore environment. The scope for application in a marine environmental is limited and would also not be cost-effective.	There are no significant environmental benefits or dis-benefits associated with this method as this method relates to the filling materials only and must be adopted in conjunction with conventional land formation. The environmental benefits / dis-benefits associated with this method are thus dependent on the conventional land formation method (dredging / non-dredging).
Floating Structures	Large buoyant structures secured in place by anchors and linked together to form a continuous platform	This option has been successfully applied to relatively small areas for light aircraft, however, the response of such a platform to severe climatic conditions and for landing / take-off of large commercial aircraft has yet to be proven. To ensure safety and operational requirements are met, extensive and long-term testing would be required, which makes this option unfavourable both in terms of cost and programme implications.	This method has the benefit of reducing the permanent changes to hydrodynamics that would result from the new land formation.

3.6.1.3 Based on the broad evaluation summarised in Table 3.13, options that do not involve ‘filled’ land formation are generally not considered suitable for projects of this scale. This is due to the need to balance safety, environmental considerations, reliability, cost and programme. All of these factors are particularly important to ensure the long-term operational viability of the project and to avoid undue risk to the future users of the third runway development. Therefore, the land formation method that has been identified as being most appropriate for the third runway project is the ‘non-dredging’ method.

3.6.1.4 An evaluation of options for ground improvement by non-dredge methods has enabled greater optimisation of the land formation method to enable further reductions in potential environmental impacts. Results of this options evaluation are presented below.

3.6.2 Ground Improvement

Design Assumptions, Criteria and Constraints

3.6.2.1 Ground improvement is the term used to refer to the modification of existing site in-situ soil to provide better performance, in terms of increasing bearing capacity and reducing the magnitude of residual settlement (and the time in which it occurs) under operational loading. In line with the outcomes of the land formation options evaluation and to minimise environmental impacts from the ground improvement activities, two prerequisites were imposed on the project at the very early stages of the design. These prerequisites are:

¡ Use of non-dredge methods only – whereby ground improvement must be done in-situ without the bulk removal of marine sediment, which will limit the release of sediment plumes during the construction phase. This will greatly reduce the potential for adverse construction-related water quality impacts and associated impacts to marine ecology. The bulk removal and disposal of dredged materials would also be avoided, thereby reducing the amount of waste generated during construction phase.

¡ Minimal disturbance to CMPs – whereby ground improvement options proposed for the CMP areas would also take into account the risk of contaminant release from the CMPs and avoid or minimise such releases wherever possible.

3.6.2.2 In addition to these prerequisites, ground improvement options may also be constrained by various other factors including soil properties; height restrictions on construction equipment due to airport operational safety requirements; water depth; marine traffic impact; presence of existing submarine utilities; and potential side-effects such as the need for surcharge application to improved ground.

Review of Ground Improvement Options

3.6.2.3 A review of the available ground improvement techniques was conducted to identify a list of possible options for evaluation. Based on the design requirements, the identified options are described in Table 3.14.

Table 3.14: Summary of Ground Improvement Techniques that have been considered

Process/Technology	Operating Principles
Cylindrical Steel Cell Cofferdam	Installation of cylindrical steel cells to create a contiguous structure. Primarily applicable for seawalls but could be used for providing confinement. The use of steel cells to create the core of the seawall would provide retention to land formation fill more quickly than can be achieved using conventional rubble mound seawall structures.
Deep Soil Cement Mixing (DCM)	Process by which cement is mixed into soil to produce a cemented soil compound with higher strength and stiffness than the original soil.
Deep-well Dewatering	Inducing water flow from the clay by pumping out from the sand layers above or below. Pumping from the upper layer draws down water and increases the surcharge weight.
Prefabricated Vertical Drains (PVDs)	Installation of synthetic strips of permeable construction to reduce the drainage paths within the soil to be treated and serve as a conduit to the sand drainage layer for extruded pore water. Application of a surcharge accelerates extrusion.
Electro-osmosis	Using an electric current to set up an electrolytic environment in which water is directed towards the cathode, causing consolidation as it migrates from the soil body.
Green-treated Mud	Excavation of marine sediment and contaminated spoil, treating with cement slurry to improve stiffness and strength, then replacing in the land formation foundation, all inside a watertight cofferdam surrounding the entire site.
Leachate Confinement Lagoons (for CMPs only)	Consolidating the spoil in the CMPs using PVDs and surcharge within watertight cofferdams, with collection and treatment of the extruded pore water
Sand Compaction Piles (SCPs)	These are vertical sand columns that are similar to vertical sand piles, with the sand compacted during installation.
Stone Columns	Creation of columns of compacted aggregate by the displacement method using vibroflots
Vacuum Consolidation	Similar to PVDs, except that the soil surcharge is replaced by a negative pressure provided by a pump operating within the sealed environment of the drainage blanket.
Vertical Sand Drains	Vertical sand columns installed by displacement method and designed to perform a similar function to PVDs.

Evaluation of Ground Improvement Options

3.6.2.4 To determine the acceptable options with due consideration to the various land uses and their foundation requirements, the 11 ground improvement options were initially compared and evaluated primarily on technical feasibility and environmental acceptability. A summary of the initial evaluation is shown in Table 3.15.

3.6.2.5 Applicable areas are generally separated into runway, seawall, and general land areas (which vary in their foundation requirements), and whether they are located within or outside of the CMPs.

Table 3.15: Summary of Initial Ground Improvement Evaluation

Process/Technology	Evaluation Summary	Applicable Areas
Cylindrical Steel Cell Cofferdam	Only applicable to seawall construction, with ground improvement in conjunction with DCM, SCP or stone columns. Provides significant programme advantages for seawall advancement as it can form part of the seawall core and act as a temporary seawall.	Seawalls outside CMPs
Deep Cement Mixing (DCM)	Deep cement mixing is a well-documented process which is carried out widely in Japan, Korea, the US and Europe to improve the strength and stiffness of soft marine sediments. Provides strong foundations and demonstrated to have minimal release of suspended sediment and pore water, therefore is considered suitable for application within the CMPs. This method would also be suitable for application outside the CMPs, but would be less cost-effective compared to other viable options.	All areas
Deep-well Dewatering	The use of deep wells has been considered in conjunction with PVDs as an alternative approach to the provision of a surcharge. However, since the surcharge will be applied as a “rolling surcharge”, this technique would only benefit the surcharging of the last areas of land formation to be treated, to minimise the disposal of surplus material.	Not generally applicable
Prefabricated Vertical Drains (PVDs)	PVDs are a proven technique for improvement of soft foundation clays below land formation in Hong Kong through the acceleration of primary consolidation settlements so that they occur during construction. However, this method does not provide a robust foundation for the runway, and are conduits for pore water release, hence unsuitable for application at CMPs. Also not suitable for rapid construction of seawall foundation improvement.	General land outside CMPs
Electro-osmosis	Variant of PVD whereby an electric current is applied to extract water from the soils. It is not suitable for use under the runway and seawalls for the same reasons as applies to PVDs, but is in a similar position to vacuum consolidation when considering general land formation, since the extracted water can be collected as part of the extraction process and treated before discharge.	General land inside and outside CMPs
Green-treated Mud	The process of confined excavation, treatment with cement and re-deposition requires ex-situ storage and does not strictly comply with the principles of non-dredge method. Even though this excavation might be carried out within a watertight cofferdam made of circular steel cylinders, there are significant potential environmental impacts arising for the excavation, since the material will need to be handled twice and stored temporarily during the process.	None
Leachate Confinement Lagoons	Containment of extruded pore water using PVD method, hence may be suitable for application at CMPs. The extruded water needs to be collected and either treated on site or taken to a bespoke facility for treatment before being discharged. This technique does not have the potential to provide a robust foundation for the runway and is not suitable for use in fast-tracked seawall foundation treatment. Therefore it would be limited to land formation within the CMPs.	General land inside CMPs
Sand Compaction Piles (SCPs)	Strong record of applicable in seawall foundations, but does not provide a robust foundation for the runway, and also a source of pore water extrusion, hence unsuitable for application at CMPs.	Seawalls and general land outside CMPs
Stone Columns	Stone columns are similar to vertical sand drains, but use aggregate instead of sand to form reinforcing columns through the soft clay. It is a relatively straightforward and cost-effective way of improving the strength and stiffness of soft clay and have been used successfully in Hong Kong in past projects, but the stone columns act as conduits for discharge of pore water, hence are considered to be unsuitable for application at CMPs.	All areas outside CMPs
Vacuum Consolidation	Variant of PVD performed in the context of extruding pore water through the application of a negative pressure to the PVDs and drainage blanket using pumps. This method is not suitable for use underwater, but could be applied inside watertight cofferdams after they had been pumped out. Extruded pore water can be collected for treatment before discharge, hence may be suitable for application at CMPs.	General land inside and outside CMPs
Vertical Sand Drains	Similar to PVD, but are installed via a displacement method that is also likely to cause significant seabed heave and disturbance. However, this method would be suitable for transitions between zones improved by methods with significant settlement differences, to offer improved control of differential settlements between the zones of markedly different stiffness.	General land outside CMPs

Note: highlighted options were identified as the preferred options to adopt for the project.

3.6.2.6 After defining the applicable areas for each ground improvement option, the relative advantages and disadvantages of each alternative were compared specifically to other applicable options. The best performing solutions were put forward for inclusion in the recommended ground improvement options. Through this evaluation process, the following ground improvement options for land formation were eliminated and not considered further:

¡ Deep-well Dewatering – only applicable as an alternative to the provision of surcharge for PVD-treated areas and does not offer much benefit compared to conventional surcharge, hence not considered further.

¡ Electro-Osmosis – generally offers no significant advantages compared to other options for general land either within or outside of the CMPs, and necessitates the removal and treatment of contaminated pore water, hence not considered further.

¡ Green-Treated Mud – not strictly a non-dredge method, involving additional engineering works to create a stable cofferdam and involves ex-situ storage and treatment, hence may be associated with additional environmental impacts.

¡ Leachate-Confinement Lagoons – necessitates the removal and treatment of large volumes of contaminated water and generally offers no significant advantages compared to other options either within or outside of the CMPs, hence not considered further.

¡ Vacuum Consolidation – not considered to be practicable as it requires construction of a ‘seal’ (e.g. cofferdam, sheet piles or diaphragm wall) to achieve an effective vacuum in the marine sediment, and consequently brings no benefit over conventional surcharge.

Environmental Benefit / Dis-Benefit – Ground Improvement Options

3.6.2.7 For the shortlisted ground improvement options, the environmental benefits and dis-benefits were evaluated and are summarised in Table 3.16.

Table 3.16: Summary of Environmental Evaluation

Process / Technology	Environmental Benefit	Environment Dis-benefit
Cylindrical Steel Cell Cofferdam	Generally not associated with significant sediment release or underwater noise impact.	No significant environmental dis-benefits associated with this method, but must be adopted in conjunction with other ground improvement methods.
Deep Cement Mixing (DCM)	This method has been demonstrated to have minimal release of suspended sediment and pore water (based on overseas applications), therefore is considered suitable for application both within and outside the CMPs.	Full scale application and its effects on water quality has yet to be proven.
Prefabricated Vertical Drains (PVDs)	Generally not associated with significant sediment release or underwater noise impact.	Creates conduits for pore water release.
Sand Compaction Piles (SCPs)	Generally not associated with significant sediment release or underwater noise impact.	Creates conduits for pore water release.
Stone Columns	Generally not associated with significant sediment release or underwater noise impact.	Creates conduits for pore water release.
Vertical Sand Drains	Generally not associated with significant sediment release or underwater noise impact.	Creates conduits for pore water release.

Note: highlighted options were identified as the preferred options to adopt for the project.

3.6.2.8 For the shortlisted ground improvement options, it was identified that there are no significant differences in environmental performance among the PVD, SCP, stone column, and vertical sand drain methods: all are associated with minimal sediment release and are equally applicable to non-CMP areas, but are considered to be non-applicable to CMP areas due to pore water extrusion. The environmental performance of the steel cell cofferdam is mainly dependent on the ground improvement method that is adopted in conjunction with this method.

3.6.2.9 The DCM method differs from the other methods in that it provides in-situ treatment and stabilisation of the marine sediment, which reduces the potential for release of contaminated pore water. While cement is injected into the sediment, the risk of cement slurry release into the water column is low provided the injection process is well controlled. Therefore, the DCM method is the only ground improvement method that is considered to be applicable to both CMP and non-CMP areas.

Selection of Preferred Scenario – Ground Improvement Options

3.6.2.10 Based on the evaluation, all of the shortlisted ground improvement options are considered to be applicable, and the preferred ground improvement options identified for application in different areas of the land formation is described below.

¡ All CMP areas – only the DCM method is considered to be acceptable for ground improvement within the CMPs as it can meet the required foundation requirements for any land use type and it does not involve removal of the contaminated mud or lead to active extrusion of a large amount of pore water from the CMPs. A small amount of pore water may be extruded from the muds between DCM columns during surcharge (equivalent to the amount of settlement in-between DCM columns), but this is substantially less than for any other ground improvement method (settlement between DCM columns is anticipated to be only 0.3 m, which is approx. 95% less compared to other ground improvement options such as PVD). A previous DCM trial conducted in Hong Kong also did not indicate any release of contaminated pore water from the CMPs, hence the adoption of this method is the most environmentally-preferable solution for ground improvement of the CMPs.

¡ Runway (non-CMP areas) – both the DCM and stone columns / vertical sand drains / SCP method can meet the more stringent foundation requirements for the runway and does not involve the dredging of soft marine deposit, hence these are both viable options for ground improvement beneath the runway strip.

¡ Seawalls (non-CMP areas) – DCM, stone columns / vertical sand drains / SCP and steel cells are considered to be the primary options for seawall construction that can meet the foundation requirements (and does not involve the dredging of soft marine deposit), whereby different areas of seawalls may be subject to different ground improvement methods depending on location and programme requirements.

¡ General Land Formation Areas – All ground improvement methods in the General Land Areas are based on the no-dredging approaches. Among the various methods, PVD has been identified as the recommended option for this area (outside of CMPs) as it has clear performance (e.g. quicker installation rate) and cost advantages compared to the other options and it has been widely adopted for other land formation projects in Hong Kong. The stone columns / vertical sand drains / SCP options were retained as potential secondary methods, while DCM remains the only viable ground improvement method for areas within CMPs, but may also be applied in areas outside the CMPs.

3.6.2.11 Based on the recommended ground improvement options, the methods proposed to be applied to the project work areas are listed in Table 3.17 and shown in Drawing No. MCL/P132/EIA/3-007. Actual combinations of ground improvement methods will be subject to future detailed design.

Table 3.17: Recommended Ground Improvement Methods

Facility	Location	Proposed Ground Improvement Method
Runway	Inside CMPs	DCM
Runway	Outside CMPs	Stone columns / SCP / Vertical sand drains / DCM
Seawalls	Inside CMPs	DCM
	Outside CMPs	Steel Cells / Stone Columns / SCP / Vertical sand drains
	Outside CMPs	DCM
General Land Formation	Inside CMPs	DCM
	Outside CMPs	PVD
		Stone Columns / SCP / Vertical sand drains¹
		DCM

¹ These have been retained as secondary methods that may be adopted alongside PVD.

3.6.3 Seawall

Design Assumptions, Criteria and Constraints

3.6.3.1 The project involves construction of approx. 13 km of new seawalls around the new land formation, which must be designed with sufficient structural capacity to withstand the action of currents and waves under normal and extreme operating conditions (e.g. during tropical storms and typhoons). The existing seawall along the northern boundary of HKIA (approx. 6 km) must also be modified to connect the new land formation with the existing airport island.

Review and Evaluation of Seawall Design Options

3.6.3.2 A number of seawall design options were reviewed as part of the scheme design for the project; generally, these comprise variations of either sloping seawall or vertical seawall. The sloping seawall options vary mainly by the options for armour (rockfill or precast-concrete blocks) and the core (mound core, circular steel cell cofferdam or jacket-type structure). The vertical seawall options vary mainly by the type of construction material (concrete or steel) and the core (with or without wave dissipation chambers).

3.6.3.3 A summary of the seawall options reviewed, as well as their relative advantages and disadvantages are presented in Table 3.18.

Table 3.18: Summary of Seawall Design Options

Seawall Type	Summary of Issues / Performance
Seawall Type	Engineering	Environmental Benefits / Dis-benefits	Other Considerations (e.g. constraints, programme, costs)
Sloping Seawalls
Rockfill sloping seawall built on mound core	Straightforward to construct and maintain	Allows reuse of rock armour from existing northern seawall to minimise waste generation Potential habitat for marine ecology	Sourcing of rock required
Precast concrete shapes sloping seawall built on mound core	Straightforward to construct and maintain	Potential habitat for marine ecology	Off-site fabrication required
Circular steel cell cofferdam with sloping rockfill seawall outside	Ground improvement required to the front and rear of each cell Corrosion protection required	Allows reuse of rock armour from existing northern seawall to minimise waste generation Potential habitat for marine ecology	Increases programme efficiency Sourcing of steel supply
Rockfill sloping seawall built on mound core with pile foundations	Requires underwater connection of base slab and pile	Allows reuse of rock armour from existing northern seawall to minimise waste generation Potential habitat for marine ecology Underwater noise from pile installation	Slow construction rate Sourcing of rock required
Rockfill sloping seawall built on jacket-type structure with pile foundations	Requires underwater assembly of jacket and precast elements Corrosion protection required	Allows reuse of rock armour from existing northern seawall to minimise waste generation Potential habitat for marine ecology Underwater noise from pile installation	Fast construction rate High risk from sourcing and underwater assembly
Vertical Seawalls
Vertical seawall with wave energy dissipation chambers	Requires good quality control and regular inspection Internal repairs difficult	No / insignificant marine ecological value	Off-site fabrication required
Vertical blockwork-type seawall	Straightforward to construct and maintain High wave reflectivity	No / insignificant marine ecological value	Slow construction rate
Vertical seawall using large steel pipe pile walls	Relatively straightforward to construct Corrosion protection required	No / insignificant marine ecological value Underwater noise from pile installation	Fast construction rate Sourcing of steel supply High capital cost and maintenance cost
Vertical seawall using circular steel cofferdam	On-site joining of steel cells required Corrosion protection required	No / insignificant marine ecological value Underwater noise from pile installation	Fast construction rate Sourcing of steel supply High capital cost and maintenance cost

Note: highlighted options were identified as the preferred options to adopt for the project.

Selection of Preferred Scenario – Seawall Design Options

3.6.3.4 Based on a review of the various seawall design options shown in Table 3.18, the adoption of rockfill sloping seawalls was identified as presenting an environmental advantage from a waste minimisation and marine ecological habitat perspective. Taking into account other factors such as constructability and programming issues, two preferred options for seawall construction were identified: ‘rockfill sloping seawall built on mound core’, and ‘circular steel cell cofferdam with sloping rockfill seawall outside’. These would be the dominant design options for the new seawall. The specific locations for implementation of these two types of preferred seawalls will depend on project requirements.

3.6.3.5 While sloping seawalls were identified as the overall preferred option, some areas of the future new seawall necessitate the adoption of a vertical seawall design, e.g. for sea rescue berths. In such cases, the ‘vertical blockwork-type seawall’ or ‘vertical seawall with wave energy dissipation chambers‘ have been identified as the preferred options to be implemented at localised areas as per project requirements. Nevertheless, these options also have potentially less environmental impact during construction compared to other vertical seawall options (e.g. compared to those which involve piling and would generate underwater noise impacts).

3.6.4 Filling Works

3.6.4.1 The construction for the land formation itself comprises primarily conventional filling activities. Due to the lack of available land access during land formation works, fill materials need to be delivered by marine vessels. The types of fill that may be adopted for use by this project is highly dependent on the land use requirements of the future land formation. In general, the types of fill material that will be adopted for this project includes graded or ungraded rockfill, public fill, sand fill, and rock armour.

3.6.4.2 Due to the stringent geotechnical and foundation requirements for the seawalls, rockfill is required at these locations. For the future superstructures and underground structures to be located on the airport expansion area, sand fill provides the best flexibility for meeting structural requirements. Public fill may also be used but is subject to control of fines content and availability from public fill sources, and will require sorting to remove unsuitable materials. Rock armour and graded rockfill filter layers are required to form the seawall’s protective layer.

3.6.4.3 Details of the filling requirements and fill sources are subject to further detailed design, however, opportunities were explored for improving the environmental performance of the filling activities by maximising the reuse of public fill where practicable and minimising the distance travelled by marine vessels for fill material import. The programming of the land formation works has also taken into account the need to minimise environmental impacts associated with filling activities by advancing the seawall construction to limit sediment plume release and staggering surcharge activities to enable reuse of surcharge materials from one works area as fill material for another. The construction programme is detailed in Chapter 4.

3.7 Consideration of Alternative Construction Methods for Marine Infrastructure Facilities

3.7.1 General

3.7.1.1 The third runway project involves construction of a large number of facilities which are required to enable effective operation of the airport expansion. These facilities and components are listed and described in Chapter 4. Many of the building and land-based infrastructure components including (but not limited to) the APM / BHS / road tunnels, road networks, drainage, sewerage, utilities, fuel hydrant system, Midfield freighter aprons and various ancillary buildings will comprise standard construction methodologies that are not anticipated to result in significant variations to the environmental performance of the project. Thus, no options assessment was conducted for construction of land-based infrastructure.

3.7.1.2 For marine-based infrastructure, considerations for alternative layouts / alignments and construction methods for the new runway approach lights and the diverted submarine aviation fuel pipelines and submarine 11 kV cables are described in this section.

3.7.2 Runway Approach Lights

3.7.2.1 New runway approach lights will be required for the new third runway and re-provisioned approach lights will be needed for the modified new ‘centre’ runway. The alignment of the runway approach light structures is fixed according to aviation requirements and will consist of rows of sequence flashing lights (approximately 11 nos.) supported by piers extending approximately 300 m offshore along the centreline from the runway threshold. Both the existing western and eastern approach lights of the existing North Runway are founded on bored piles. The piers are joined by linking bridges in steel or concrete and utilities are protected by a series of ducts underneath.

Evaluation of Marine Piling Options

3.7.2.2 The outwards section of the new approach lights would be installed in the marine waters at either end of the eastern and western ends of the third runway. Given the sensitivity of the surrounding marine environment, percussive piling methods (which involve the use of impact devices such as drop hammers for driving piles into the ground which can generate high noise levels) would not be considered. The piling options considered included:

¡ For approach lights on the western end (outside CMP area): inclined pre-bored H piles, driven H piles, and large diameter bored piles

¡ For approach lights on the eastern end (within CMP area): inclined pre-bored H piles, driven H piles, and large diameter bored piles on DCM-improved seabed and sub-soil profile.

3.7.2.3 The option of Driven H piles was initially ruled out of consideration as this method has limited capacity to withstand the impact loads of marine vessels, hence this has not been considered further. A comparison of the environment benefits / dis-benefits of the remaining two piling options are presented in Table 3.19.

Table 3.19: Summary of Environmental Benefits / Dis-benefits Associated with the Marine Piling Options

Piling Option	Environmental Benefit	Environmental Dis-benefit
Inclined pre-bored H piles	Spoil removal would be comparatively less per pile than large diameter bored piles. Noise and vibration performance is similar to large diameter bored piles.	Not preferable for use in CMP area. This method would result in more disturbance to the existing CMP sediment as piles will need to be inclined to resist the lateral load: thus the affected area would be greater than vertical piles.
Large diameter bored piles	For DCM-treated sediment in CMP areas, the affected area would be smaller compared to inclined pre-bored H piles. Noise and vibration performance is similar to inclined pre-bored H piles.	Spoil removal would be comparatively more per pile in comparison to inclined pre-bored H piles.

Piling Option

Environmental Benefit

Environmental Dis-benefit

Inclined pre-bored H piles

Spoil removal would be comparatively less per pile than large diameter bored piles.

Noise and vibration performance is similar to large diameter bored piles.

Not preferable for use in CMP area. This method would result in more disturbance to the existing CMP sediment as piles will need to be inclined to resist the lateral load: thus the affected area would be greater than vertical piles.

Large diameter bored piles

For DCM-treated sediment in CMP areas, the affected area would be smaller compared to inclined pre-bored H piles.

Noise and vibration performance is similar to inclined pre-bored H piles.

Spoil removal would be comparatively more per pile in comparison to inclined pre-bored H piles.

Selection of Preferred Scenario – Marine Piling Options

3.7.2.4 Bored piling is the preferred foundation system to support the approach light structures due to its comparatively high loading capacity and reduced potential for disturbance to the surrounding environment. Based on the evaluation, both inclined pre-bored H piles and large diameter bored piles have their advantages for different areas of application, and their environmental performance is similar. Thus, both options are considered suitable for use and the actual method to be adopted will be subject to future detailed design.

3.7.2.5 At the western end section of approach lights (located in non-CMP areas), it is proposed that either the pre-bored piles or the large diameter bored piling method can be adopted. For the eastern approach lights (located in CMP areas), the large diameter bored piles are considered to be more suitable as the area of CMPs disturbed would be less than that of inclined pre-bored H piles. While a relatively larger volume of spoil will be generated using large diameter bored piles, the CMPs would be treated with DCM (to stabilise the marine sediments) prior to piling activities. This will prevent the release of marine sediment during drilling of the casing into the seabed and reduce the potential water quality impacts associated with marine piling within CMP areas.

3.7.3 Diversion of Submarine Aviation Fuel Pipelines

Review of Existing Aviation Fuel Pipelines Arrangement

3.7.3.1 The existing airport island is currently supplied with aviation fuel via twin 500 mm diameter submarine aviation fuel pipelines that originate from Tuen Mun permanent aviation fuel facility (PAFF) to the aviation fuel receiving facility (AFRF) at Sha Chau and then to the aviation fuel tank farm (AFTF) on the airport island. The existing pipeline landing point at the airport island is located at the seawall adjacent to the north Perimeter Road near the northwest tip of the existing North Runway. The total length of the existing pipelines between Sha Chau and the airport island is approximately 6 km, of which 3 km is located below seabed within the Sha Chau Marine Park. The pipelines are generally buried 10 m below the seabed to provide adequate protection from possible vessels and anchor damage.

3.7.3.2 AFRF at Sha Chau currently operates as a backup facility in case of emergency incidents at PAFF, as any prolonged disruption in the supply of aviation fuel will have serious adverse impact on HKIA operations. To ensure the continuous supply of aviation fuel to HKIA, AFRF is required to provide the built-in redundancy in the aviation fuel system design, minimising risks associated with any prolonged disruption to the airport’s fuel supply. Consequently, the diverted pipelines must maintain the connection between AFRF and AFTF on the airport island.

Options for Diversion of the Aviation Fuel Pipeline

3.7.3.3 The land formation for the project will require ground improvement works to be carried out beneath the seabed where the existing aviation fuel pipelines are located. With the existing pipelines in place, the marine deposit and alluvium beneath the pipelines cannot be treated, hence if the pipelines are not diverted, significant differential settlement will occur between the treated and untreated areas, leading to damage to the pipelines, which would adversely affect the airport’s operation and efficiency. Thus it is deemed necessary to divert the pipelines prior to any land formation works.

3.7.3.4 To ensure the full and proper operation of the aviation fuel supply system, three diversion options for the pipelines have been considered. These options are shown in Drawing No. MCL/P132/EIA/3-009 and described in Table 3.20.

Table 3.20: Options for Submarine Aviation Fuel Pipeline Diversion

Option	Description of Alignment	Description of Construction Method
Option 1 - Open Trench C-curve to West of Sha Chau	The general alignment of the replacement pipelines can be laid from the verge area on the northern side of the Airport South Perimeter Road near the existing Hong Kong Aircraft Engineering Company Limited (HAECO) hangar. To avoid encroaching onto the existing runway, the twin submarine fuel pipelines are aligned to run around the western side of the proposed runway, beyond the future runway approach lights, then up to the Sha Chau jetty. The pipeline connection will be similar to the existing pipeline system at the Sha Chau AFRF.	Conventional open trench installation where 10m deep trench below the seabed will be excavated by barge excavator followed by pipe lay-barge. Short pipe strings can be prefabricated on-shore and further welded onboard the lay-barge depending upon the progress of the trench excavation. The trench will then be backfilled with rock armour for protection. The total length of this diversion is approximately 9 km with 4 km to be laid within the Sha Chau Marine Park.
Option 2 - Open Trench S-curve to East of Sha Chau	The replacement pipelines start from the verge on the north of the Airport South Perimeter Road near the existing HAECO hangar, in order to avoid encroaching onto the existing runway operation. The proposed fuel pipelines then run around the western side of the third runway, beyond the future runway approach lights, then re-route to the east around the proposed third runway to minimise interruption within the Sha Chau Marine Park. The pipeline connection will be at the Sha Chau AFRF.	The construction method for Option 2 will be similar to that for Option 1. The total length of this diversion is approximately 10 km, of which 0.5 km will be laid within the Sha Chau Marine Park.
Option 3 - Horizontal Directional Drilling (HDD) from Airport to Sha Chau	This option involves the installation of the two new fuel pipelines by the HDD method through the bedrock. The new fuel pipelines will surface near the Sha Chau AFRF. The pipework can then be connected along the existing footbridge and further routed to AFRF.	The construction method will utilise the HDD technique, which involves the installation of pipes, conduits, and cables in a shallow arc using a surface-launched drilling rig and a steerable down hole system commonly used in drilling oil and gas wells. The total length of this diversion route is approximately 5 km.

Evaluation of Aviation Fuel Pipeline Options

3.7.3.5 The three aviation fuel pipeline options were reviewed technically and environmentally. The main technical considerations included design, construction, maintenance, and operation, while the environmental considerations focused on impacts to water quality, marine ecology (including disturbance to Sha Chau and Lung Kwu Chau Marine Park), and waste management. A summary of the evaluation is presented in Table 3.21.

Table 3.21: Review of Technical and Environmental Considerations for Pipeline Diversion

Option	Technical Considerations	Environmental Benefits / Dis-benefits
Option 1 - Open Trench C-curve to West of Sha Chau	Design: straightforward, no specific risks. Construction: main construction risks include, pipe buckling, pipe being struck by anchors during construction. Risks for the permanent installation include scour of the seabed, potential rock armour exposure and subsequent pipe undermined. Inspection and Maintenance: regular inspection of the pipeline required. Maintenance may be problematic and may require re-exposure of pipes.	Water Quality: high potential for water quality impact due to sediment release from trench dredging activities. Marine Ecology: high potential for marine ecological impact with 4 km of alignment within the Marine Park area. Waste: approx. 3,120,000 m³ of dredged materials will be generated by the approx. 9 km long trench dredging activities. Potential need for disposal of contaminated sediment.
Option 2 - Open Trench S-curve to East of Sha Chau	Similar to Option 1. Additional risk of crossing the existing pipelines and the existing high voltage cables.	Similar to Option 1. Encroachment into Marine Park is limited to 0.5 km, but longer alignment has potential to generate larger water quality impact. About 3,570,000 m³ of dredged materials will be generated by the approx. 10 km long trench dredging activities.
Option 3 - Horizontal Directional Drilling (HDD) from Airport to Sha Chau	Design: specialist field and specialist contractors required. Construction: main construction risks include, leaking of bentonite at the loose material, rock suitability at Sha Chau, drilling problems, damaged pipe coating, and capture of bentonite on break through. Inspection and Maintenance: unlikely to require any maintenance once successfully installed.	Water Quality: limited to localised areas at the launching and landing points for the drilling activities. Marine Ecology: no direct disturbance to seabed, but some direct disturbance on-land at the landing point. Some terrestrial ecology at Sheung Sha Chau may be affected. Waste: approximately 5,700 m³ of excavated materials will be generated, but would be suitable for reuse in the land formation.

Preferred Aviation Fuel Pipeline Option

3.7.3.6 As identified in the evaluation, Option 3 is associated with the least potential environmental impacts, making it the preferred option from an environmental perspective.

3.7.3.7 Technically, the HDD technology has been applied successfully since the 1970’s. It is currently an efficient, safe, cost-effective method for crossing highways and rivers and is the current industry standard for trenchless technology for utility bores between 100 and 600 mm diameters and from 200 m up to 3 to 4 km in length. In recent years in Hong Kong, HDD method of construction had been adopted in submarine cable installations. Successful projects include from Ma Wan to Sham Tseng, Ma Wan to Lantau Island as well as Pui O and Chi Ma Wan.

3.7.3.8 Given the findings of the options evaluation, Option 3 was identified as the preferred option for diversion of the submarine aviation fuel pipelines and is taken forward for full environmental assessment.

3.7.4 Diversion of Submarine 11 kV Cables

Review of Existing Submarine 11 kV Cables Arrangement

3.7.4.1 There is currently one set of 11 kV submarine power cables providing power supply from the northwest of the airport island to Sha Chau and Lung Kwu Chau islands. These cables are buried approximately 3 m below the seabed. The power supply to Sha Chau is critical to the operation of HKIA since there is a CAD radar station, a Hong Kong Observatory (HKO) station, and AFRF located at Sha Chau. The radar station and HKO station are important facilities that collect data for the safe operation of flights to and from the airport, while the aviation fuel supply from PAFF to HKIA is supported by AFRF as an emergency backup facility. Any disruption to the operation of these facilities at Sha Chau would thus have negative consequences on aviation control and emergency fuel supply operations at HKIA.

3.7.4.2 The land formation for the project will require ground improvement works to be carried out beneath the seabed where the existing submarine 11 kV cables are located. With the existing cables in place, the marine deposit and alluvium beneath the cables cannot be treated. Therefore, if the cables are not diverted, significant differential settlement will occur between the treated and untreated areas, leading to damage to the cables, which would adversely affect the power supply to facilities at Sha Chau. In order to maintain a continuous power supply, diversion of these existing power cables is required to avoid any impact from the construction of the third runway.

Options for Diversion of the Submarine 11 kV Cables

3.7.4.3 To ensure the full and proper operation of the submarine 11 kV cables, the options that have been considered for the diversion of these existing cables are shown in Drawing No. MCL/P132/EIA/3-010 and described in Table 3.22.

Table 3.22: Options for Submarine 11 kV Cable Diversion

Option	Description of Alignment	Description of Construction Method
Option 1 - Direct bury from the airport to south of the Marine Park Boundary	Option 1 is to lay cables from the west side of HKIA near South Perimeter Road to at least 500 m south of the Marine Park boundary by direct burying. The installation distance is approximately 6 km.	The proposed diversion cable will be laid by either open trench method or water jetting method to about 5 m below the seabed. For open trench method, a trench will be excavated and backfilled with aggregates. For installation by water jetting method, no trench excavation is required and the trench would be backfilled with the original seabed materials. A field joint will be made outside the Marine Park boundary for the connection between the existing and the proposed diversion cable. Prior to the connection works, excavation will be carried out to expose the existing cable which will then lifted up to a barge for forming the field joint. The excavated trench will then be reinstated and backfilled with aggregate on the top.
Option 2 - Horizontal directional drilling (HDD) from the airport to Sha Chau	Option 2 is to install new cables through a drillhole which is formed by HDD. The drilling would start from the west of the airport directly to Sha Chau through the bedrock layer to about -60 mPD. The total drilling distance is approximately 4 km.	The electric power cable and pilot cable will be pulled from the start point at the airport to the end point at Sha Chau. Cable ducts may be required inside the drillhole for drawing cables.
Option 3A - Direct bury from the airport to the northwest of Sha Chau	Option 3A is to lay cables from the airport island to northwest side of the Sha Chau by direct burying. This proposed cable alignment starts from the west side of the airport near South Perimeter Road to Sha Chau with a length of approximate 7 km. The proposed installation works will cross the Sha Chau Marine Park from the south.	The proposed diversion cable will be laid to 5 m below the seabed by either open trench method or water jetting method (similar to Option 1).
Option 3B - Direct bury from the airport to the east of Sha Chau	Option 3B is similar to Option 3A, but the cables will be laid across the Sha Chau Marine Park and finally land at the east of Sha Chau. The cables will run from the west side of the airport near South Perimeter Road to east side of Sha Chau for a length of approximate 9 km.	Similar to Option 1 and 3A
Option 4 - Direct bury from Tuen Mun to the east of Sha Chau	Option 4 is to lay the proposed cable from southwest of Tuen Mun to east of Sha Chau with a length at approximately 5 km long. The proposed landing point at Tuen Mun is at Eco Park where land of 6 m by 8 m in size would be available for the construction of a sub-station.	Similar to Option 1, 3A and 3B

Evaluation of Submarine 11 kV Cable Options

3.7.4.4 The five submarine 11 kV cable options were reviewed technically and environmentally. The main technical considerations included feasibility and maintenance, while the environmental considerations focused on impacts to water quality, marine ecology, and waste management. A summary of the evaluation is presented in Table 3.23.

Table 3.23: Review of Technical and Environmental Considerations for Cable Diversion

Option	Technical Considerations	Environmental Benefits / Dis-benefits
Option 1 - Direct bury from the airport to south of the Marine Park Boundary	Field joint works would require temporary suspension of power to Sha Chau and Lung Kwu Chau islands. Arrangements for temporary power supply would be required.	Water Quality: medium potential for water quality impact due to sediment release. Marine Ecology: medium potential for marine ecological impact, however, all construction activities will take place outside the Marine Park area. Waste: some excavated materials (approximately 10,200 m³) will be generated at the field joint and will require disposal.
Option 2 - Horizontal directional drilling (HDD) from the airport to Sha Chau	This option is not considered to be technically feasible due to the high tension capacity requirements for pulling the power cables across approx. 5 km. High risk of damage to power cables during installation.	As this option is not technically feasible, no further consideration is made.
Option 3A - Direct bury from the airport to the northwest of Sha Chau	No major technical issue.	Similar to Option 1, but involves a longer alignment with direct impacts within the Marine Park. Both water quality and marine ecological impacts would be high.
Option 3B - Direct bury from the airport to the east of Sha Chau	Significantly longer alignment. Potential issues associated with repairs in high marine traffic areas and the need to cross the existing submarine cables.	Similar to Option 3A, but with less direct impact to the Marine Park, however, the overall longer alignment would affect a larger area of marine habitat.
Option 4 - Direct bury from Tuen Mun to the east of Sha Chau	New substation required for this option. Landing location needs to be acquired.	Similar to Option 3B, but the shorter alignment would create relatively less impact to marine habitat. Disposal of excavated materials / C&D waste may also be required at the landing point in Tuen Mun.

Note: All Direct Bury options were compared on the assumption of construction via water jetting method as opposed to open trench method.

3.7.4.5 Option 2 was the only option determined not to be technically feasible for the length of alignment required. Of the remaining options, all could be constructed by either water jetting or open trench methods. Water jetting method is generally more preferable as trench excavation (and associated disposal of excavated materials) is not required. The water jetting method involves the use of a jetting machine to open up a gap at 5 m below the seabed. Having laid the cables inside the gap, the trench is then backfilled with original seabed materials.

3.7.4.6 Based on the evaluation of the feasible options and with the assumption that all methods would adopt construction via water jetting instead of open trench, the most environmentally preferable option would be either Option 1 or Option 4. Option 1 has the benefit of not encroaching into the Marine Park, which is more favourable for the preservation of important marine habitat. It should be noted that Option 1 has a slightly longer alignment than Option 4. Therefore, there may be slightly more temporary disturbance to the seabed and release of sediment. From a technical perspective, Option 4 is generally less preferable due to the additional permanent infrastructure provisions required, and the associated implications on future operations and maintenance, particularly along the busy Urmston Road navigation channel.

Preferred Submarine 11 kV Cable Option

3.7.4.7 In view of the fact that environmental and technical issues associated with Option 1 is largely temporary while Option 4 would create some permanent impacts, Option 1 via water jetting method is considered to be the overall preferred option for diversion of the submarine 11 kV cables.

3.8 References

1. Airport Authority Hong Kong, Hong Kong International Airport, Airspace and Runway Capacity Study Phase 2, Deliverable P6, Final Runway Options Report, August 2008, NATS, http://vps.hongkongairport.com/mp2030/consultancy_report/NATS_phase2.pdf

2. Civil Aviation Department, Government of Hong Kong Special Administrative Region. Aircraft Noise Management, http://www.cad.gov.hk/english/ac_noise.html

3. Airport Authority Hong Kong, Hong Kong International Airport, HKIA Master Plan 2030 Technical Report, July 2011, http://vps.hongkongairport.com/mp2030/TR_24May_Eng_Full.pdf

4. Airport Authority Hong Kong, Hong Kong International Airport, Airspace and Runway Capacity Study Phase 1b, Deliverable P2, Final Report, December 2008, NATS, http://vps.hongkongairport.com/mp2030/consultancy_report/NATS_phase1b.pdf

5. Airport Authority Hong Kong, Hong Kong International Airport, Contract P132 – Engineering Feasibility and Environmental Assessment Study for Airport Master Plan 2030, Comparative Environmental Assessment Report, (Deliverable D1.8), May 2009, Mott MacDonald Hong Kong Limited, http://vps.hongkongairport.com/mp2030/consultancy_report/Mott_1.pdf

3.1.1.2 This section identifies options and opportunities available for provision of a third runway in Hong Kong, in terms of its alignment, the associated airport layout and construction methods.

3.1.2.1 This section is structured as follows:

Section 3.2 – General Considerations presents the objectives of the airport expansion and the main constraints to operation of the existing runways.

Section 3.3 – Consideration of Alternatives for the Third Runway Alignment presents the runway alignment options assessment leading to identification of the shortlisted alignments.

Section 3.4 – Consideration of Alternatives for Airport Layout under a Three-Runway System presents the engineering and environmental evaluation of the shortlisted airport layout options leading to identification of the preferred option.

Section 3.5 – Further Development of the Preferred Runway and Airport Layout presents the further considerations and fine-tuning of the preferred option leading to the preferred runway and airport layout.

Section 3.6 – Consideration of Alternative Construction Methods for Land Formation presents the options for ground improvement and seawall construction leading to the recommended construction method for land formation.

Section 3.8 – References lists all the reference documents which have been referred to in this section.

3.2.1 Objectives of Airport Expansion

3.2.1.1 The need for airport expansion has been elaborated in Chapter 2. If a three-runway system (3RS) is developed, it must meet the needs of the aviation sector in Hong Kong and the aspirations of the public through the following attributes:

3.2.2 Review of Existing Configuration and Constraints

3.2.2.1 At present, there are two runways at HKIA. These parallel runways are aligned along 07/25 orientation (i.e. runways aligned along an axis of 70° and 250° from the north). The runways are slightly staggered with a 1,540 m separation [1].

3.2.2.4 Territorial boundaries affect runway operations by restricting the permitted flight routes for arrivals and departures from outside of Hong Kong Special Administrative Region (HKSAR). This constraint is however partially negotiable.

3.3 Consideration of Alternatives for the Third Runway Alignment

3.3.1.2 This section describes the methodology adopted for consideration and evaluation of different runway alignment options as well as summarising the assessments leading to identification of a shortlist of alignment options.

3.3.2.1 To evaluate the runway alignment options, both a set of evaluation criteria and a long list of runway options were first defined. A process was then developed for reviewing each option against the relevant criteria to identify differences in performance between options.

3.3.2.3 These evaluation criteria were the main consideration in assessing and comparing individual alignment options during different stages of the evaluation process.

3.3.2.4 The evaluation process comprised the following steps:

Option A

Option B

Option C

Option D

Option E

Option F

Option G

Option H

Option J

Option K

Option M

Option N

Option P

Option R

Option S

Option S Extended (Variant A and B)

Option S Extended (Variant C)

Option S Extended (Variant D)

Option S Extended (Variant E)

3.3.4 Options for the Third Runway Alignment Stage 2 – Shortlisted Options

3.3.4.2 The following summarises findings from the operational compliance review:

3.3.4.3 As the operational review identified that runway alignment Options P, R and the revised Option S were all operationally feasible, these three runway alignments were adopted as the basis for evaluating a range of potential airport layout options.

3.4.1.1 The evaluation process for airport layout alternatives is shown in Chart 3-1 and comprised the following key steps:

Initial Stage: A broad evaluation of constructability and operational requirements to create a shortlist of airport layout options for detailed evaluation.

Final Stage: A detailed evaluation covering both non-environmental considerations and environmental considerations, leading to identification of a preferred option.

Starting Point

Initial Stage

Final Stage

3.4.1.2 Details of the airport layout evaluations are presented in the following subsections.

LEGEND

A, B, C & D show possible location of passenger processing terminal (where passengers are processed for check-in, Customs/Immigration/Quarantine and security screening)

X, Y & Z show the possible location of aircraft apron and passenger concourse area (where aircraft gates are located)

P, R & S denote spacing between the third and existing North Runways (i.e. far-spaced, normal-spaced and close-spaced) respectively

3.4.2.3 Four airport layout options were shortlisted as a result of the qualitative review as shown in Drawing Nos. MCL/P132/EIA/3-001 to MCL/P132/EIA/3-004. The main characteristics of the shortlisted options are summarised in Table 3.4.

3.4.3 Final Stage of Non-Environmental Evaluation

Westward Expansion - Option S (D+Z)

Northward Expansion - Option P (A + Y), Option R (A + X) and Option R (A + Y)

The outcome of the non-environmental relative performance evaluation of the two families of airport expansion options, as set out in MP2030, is recapped in Table 3.5.

3.4.3.2 A summary of the comparison between the Westward expansion option relative to the Northward expansion option is as follows:

Airfield Efficiency

Passenger Convenience

Surface Access Quality

Cargo Operations Efficiency

3.4.4 Environmental Evaluation under MP2030

3.4.4.6 The findings of the comparative environmental evaluation identified Option 3 as performing relatively better than the other options with respect to the majority of environmental differentiators.

3.4.5.1 The results of both non-environmental and environmental evaluations concluded that Option 3 – R (A + Y) is the best performing option of those shortlisted. Option 3 – R (A + Y) was also recommended as the preferred three-runway MP2030 layout.

3.4.6.3 Taking into account the environmental benefits identified in Table 3.10, the preferred Option 3 was revised accordingly and the improved preferred option is shown in Drawing No. MCL/P132/EIA/3-005.

3.5.1.2 These changes were primarily due to operational requirements, and given that the modified layout remains conceptually similar to the preferred option, the environmental performance of this modified layout is expected to be consistent with the preferred option.

3.5.2.1 As part of the initial scheme design for the project, a number of concourse layout options were considered and evaluated. Table 3.11 presents a summary of the TRC options that were considered for the 3RS.

3.5.2.5 Accordingly, the preferred scenario would provide environmental benefits in terms of: