Under the Environmental Impact Assessment Ordinance, the Environmental Impact Assessment (EIA) Report (Register No.: AEIAR-254/2023) prepared for the Airport Tung Chung Link Project (the Project) has been approved by the Environmental Protection Department (EPD). An Environmental Permit No. EP-630/2023 for the construction and operation of the Project was first granted by Director of Environmental Protection (“DEP”) to Airport Authority Hong Kong (“AAHK”) on 26 October 2023. Subsequently an application for variation of the EP was submitted on 3 November 2025 and the current valid EP (No. EP-630/2023/A, hereinafter known as “the EP”) was issued by EPD on 1 December 2025. Pursuant to Condition 2.13, AAHK shall prepare a Silt Curtain Deployment Plan (“SCDP”) for covering marine works that involve the deployment of silt curtain under this Project.

This Project consists of constructing a 3.8km vehicular road, named as the Airport Tung Chung Link (“ATCL”). This road will extend the passenger transport services using autonomous vehicles (“AV”) from the Airport City Link (“ACL”) to Tung Chung, aiming to enhance connectivity between the Hong Kong-Zhuhai-Macao Bridge (“HZMB”) Hong Kong Port (“HKP”), SKYCITY and Tung Chung. The marine facilities in the waters between Airport Island and HKP Island, and the spur line running from the HKP Island to connect the Academy Station are included in the Project EIAR (Register No. AEIAR-254/2023) and the Project EP (EP No. EP-630/2023/A), however, the construction of marine facilities and spur line is not included in the current stage of ATCL construction. The SCDP for remaining marine works will be provided separately.

Penta-Ocean Construction Company Limited (“POC”) is the Main Contractor of the Project and responsible for the marine viaduct construction which situated in a marine area between Lantau Island and Airport Island. This Silt Curtain Deployment Plan will include the marine viaduct construction area which situated in a marine area between Lantau Island and Airport Island. The proposed marine facilities in the waters between Airport Island and Hong Kong Boundary Crossing Facilities are not included in this submission.

1.2 Project Description

The Project (under EP Permit No.: EP-630/2023/A) will comprise:

• A 2.8km at-grade section along the eastern coast of Airport Island with intermediate stops;

• An overall 1km length of viaducts consisting of three sections (a land viaduct over Tung Chung town centre, a marine viaduct between Lantau Island and Airport Island and a land viaduct connecting with ACL at HZMB HKP);

• An elevated Tung Chung Central Station (TCCS) near Tat Tung Road;

• A depot for autonomous vehicle;

• A promenade; and

• Leisure supporting facilities, and the associated ancillary buildings and facilities.

As mention in Section 1.1, the construction of marine facilities and spur line of ATCL (including Academy Station) as stated in the Project EIAR and the Project EP are not included in the current stage of ATCL construction, and was thus not included in this SCDP”.

1.3 Purpose and Scope

As specified in Condition 2.13 of the EP:

“The Permit Holder shall, no later than 2 months before the commencement of marine works involving deployment of silt curtains of the Project, deposit 3 hard copies and 1 electronic copy of a silt curtain deployment plan (SCDP) with the Director. The Plan shall include the construction programme of marine works and details on the design, location, operation and maintenance of silt curtain(s) to be deployed during the marine works. The Plan shall be fully and properly implemented.”

This SCDP has been prepared in accordance with the EP requirements and details the requirements for implementation of silt curtains during the Project construction phase. This Silt Curtain Deployment Plan will include the marine viaduct construction area which situated in a marine area between Lantau Island and Airport Island.

1.4 Report Structure

Following the introductory section, the SCDP is structured as follows:

Section 2 Construction Works involving Deployment of Silt Curtain

Section 3 Silt Curtain Design and Location

Section 4 Operation and Maintenance

Section 5 Regular Checking and Monitoring

2 CONSTRUCTION WORKS INVOLVING DEPLOYMENT OF SILT CURTAIN

2.1 General

Deployment of silt curtain has been recommended for marine construction in the approved ATCL EIA report. The marine works activities during construction phase as stipulated in Section 2.2 will involve deployment of silt curtain.

The deployment of silt curtain will be commenced on 1 March 2026, and the marine piling works will be commenced on 1 April 2026. Construction programme involving deployment of silt curtain can be referred to the Appendix A.

The construction of marine viaduct section would involve the installation of 4 set of bridge piers (2 piles for each set, totaled 8 piles) across the Tung Chung Navigation Channel. A temporary working platform would be installed after installation of silt curtain(s) to surround the active marine works area for the marine viaduct and all subsequent piling work would be conducted by piling plants on top of the temporary working platform. Bored piling for the marine viaduct crossing the Tung Chung Navigation Channel would be conducted with the silt curtain remains in place.

Hanging type silt curtain will be deployed at the surrounding of each set of bridge piers (Bridge Pier 8 to Bridge Pier 11) for a marine viaduct between Lantau Island and Airport Island. Total of 4 individual silt curtains will be provided for the marine viaduct construction works.

Appendix C shows the site location and layout plan of the proposed marine works.

2.2 Construction Activities Involving Deployment of Silt Curtain

2.2.1 Marine Piling Works

As per the approved ATCL EIA Section 5.7.1.1 recommendation, silt curtains would be installed to surround the piling area prior to establishing piling equipment on barge, installing the steel pile casing and setting out the temporary working platform. The silt curtain will be kept in place throughout the bored piling works, including grabbing, drilling by Reverse Circulation Drilling (RCD), airlifting, reinforced cage installation and concreting for piles and pile caps.

The construction of marine viaduct section would involve the installation of 4 set of bridge piers, Bridge Pier 8 to Bridge Pier 11 (2 piles for each set, totaled 8 piles) across the Tung Chung Navigation Channel. At most two marine piles will be installed/constructed concurrently at the viaduct works area across Tung Chung Navigation Channel during the construction phase. After installation of silt curtain(s) to surround the active marine works area for the marine viaduct, a temporary working platform that sits on support casings (with or without reinforcing by mini-piles) would be installed. The support casings will be positioned to the seabed by vibratory hammer from a barge. Such operation is expected to result in limited level of localized disturbance to bottom sediment, particularly when controlled by the surrounding silt curtain. In case mini-piles support is needed, the temporary support casings will be lowered until reaching the rock head until rock socket is formed. After securing the support casings, a temporary working platform would be installed on top of the casings and all subsequent piling works would be conducted by piling plants on top of the temporary working platform. Bored piling for the marine viaduct crossing the Tung Chung Navigation Channel would be conducted with the silt curtain remains in place.

3 SILT CURTAIN DESIGN AND CONSTRUCTION SEQUENCE

3.1 Types of Silt Curtains to be Deployed

Hanging Type silt curtain is proposed to be installed around Bridge Pier 8 to Bridge Pier 11. The following sub-sections outline the technical requirements of the silt curtain.

3.2 Requirements for Hanging Type Silt Curtains

Hanging Type silt curtains mainly comprise the geotextile fabric with ballast chain / weight and floatation. The geotextile fabric shall be connected all four sides using polypropylene rope with sufficient overlap to prevent leakage of suspended solids. The floatation is contained within a sleeve or collar with adequate buoyancy to support the full weight of the silt curtain. The bottom end of the silt curtain is weighted by a ballast chain incorporated into the hem of the silt curtain as to keep the silt curtain vertical during deployment.

The length of silt curtain deployed at the marine piling area will account for a buffer depth to ensure no gaps between the skirt of the silt curtain and seabed and cater for site irregularities and tidal variations.

To ensure the quality of silt curtain, the supplier must be quality certified (i.e. ISO 9001 or equivalent) and relevant project references / records of field tests demonstrating the silt curtains applicability for deployment in open sea marine environments and conditions comparable to those in Hong Kong waters shall be provided. Details are provided in Appendix B.

3.3 Arrangement for the Silt Curtain Deployment Location

Before installation of temporary working platform commences, deployment of silt curtain is necessary. Silt curtain will be installed around the works area for demarcation and prevention of water quality impacts. The marine viaduct works area is shown in Appendix C.

3.4 Pre-Condition Survey

A Bathymetric Survey will be conducted to check the depth of the seabed and existing seabed condition using the Multibeam Sonar. The Survey coverage will be within the works area of the marine viaduct. The primary purpose of this survey is to detect any vertical anomalies (high-spots or low-spots) present on the seabed within the work area so that can pre-plan the working methodology on the marine viaduct. Aside from pre-planning of the working methodology, the length of the silt curtain can be determined. The sample Bathymetric Survey Record is shown in Figure 3.1.

Figure 3.1: Sample Report of Bathymetric Survey on the Marine Viaduct

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3.5 Procedures for Pre-Assembly of Silt Curtain

1. The pre-assembly of silt curtain will be conducted on deck of a 90T Crawler Crane Barge.

2. A 15m span of pre-assembled silt curtain will be connected to a 10m span of pre-assembled silt curtain to form a 25m long silt curtain section. Two 25m long silt curtain sections will be connected to form a 50m long silt curtain (2 nos. of 15m span silt curtain and 2 nos. of 10 m span silt curtain). Each connection will use the D-shackles and Polypropylene rope for stitching as shown in Figure 3.2.

3. Each pre-assembled silt curtain will be connected to another span of silt curtain using a D-shackle at the top, middle, and bottom connection points of the steel end plates.

4. The eyelets of the pre-assembled silt curtain will be threaded with a polypropylene rope in a zigzag pattern to connect the sections.

5. A ballast chain will be inserted into the chain pocket at the bottom of the pre-assembled silt curtain to provide weight and stability.

6. To safely secure the ballast chain pocket, a larger D-shackle will be attached to the lowest point of the connecting steel plate to support the weight of the ballast chain and avoid wear and tear on the ballast chain pocket.

Figure 3.2: Details of Stitching Two Spans of Pre-assembled Silt Curtain

PRE-ASSEMBLED SILT CURTAIN

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7. After interconnecting all 4 spans of silt curtain, fold the assembled silt curtain, starting from the ballast chain pocket and working up towards the floatation end as shown in Figure 3.3.

Figure 3.3: Folded Silt Curtain

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3.6 Installation of Silt Curtain

1. Anchoring concrete blocks will be used to keep the silt curtain vertical during deployment and would be settled at its designated positions before launching the silt curtain into the sea.

2. Four sets of pre-assembled silt curtain would be loaded to the 90T crawler crane barge and towing into the marine viaduct area by tugboat.

3. Upon reaching the marine viaduct area, the crawler Crane will drop its anchor on the seabed. The tugboat will release its towlines once all 4 anchors of the crawler crane barge has been set on the seabed as shown in Figure 3.4.

Figure 3.4: 90T Crawler Crane Anchor Drop at the Working Vicinity

4. The crawler crane barge will moor towards the silt curtain deployment locations and load down the folded silt curtain into the sea. Sub-buoys will be installed on the silt curtain first before the diver dives down and secure the silt curtain to the anchoring concrete blocks. Illustration of silt curtain set up is in Figure 3.5.

Figure 3.5: Diagram of Silt Curtain Set Up

5. The crawler crane will navigate the position of the silt curtain (see Figure 3.6) to its next position then repeat step until completing all 4 silt curtain positions as shown in Figure 3.7.

Figure 3.6: Navigating the Silt Curtain

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Figure 3.7: Completed Installation of Silt Curtain

4 OPERATION AND MAINTENANCE

4.1 Deployment of Silt Curtain

Silt curtain will be deployed at marine viaduct Bridge Pier 8 to Bridge Pier 11 prior to marine bored piling. The details of work sequence can refer to Section 3.5 to 3.6.

4.2 Operation of Silt Curtain

Silt curtain will remain in place throughout the marine piling works and will be removed after the completion of marine works (i.e. concreting for piles and pile caps) and the dismantling of temporary working platform. Regular checking and monitoring will be carried out during the operation of the silt curtain (see Section 5).

4.3 Procedures for Adverse Weather Conditions

During adverse weather conditions (e.g. typhoon signal No.3 or higher), no marine works will be conducted and the silt curtain will be retracted where possible to avoid unnecessary damage. After typhoon signal No.3 is lowered, the silt curtain will be re-deployed prior to re-initiation of marine works around the bridge piers.

The Contractor will ensure the silt curtain is undamaged or will repair or replace the affected silt curtain before relevant marine works are re-initiated. Re-deployment of silt curtains where required, shall follow the procedures specified in Section 3.5 to 3.6.

4.4 Maintenance of Silt Curtain

Before commencement of marine works, daily visual inspection on the silt curtains will be conducted, any damage or faults identified in the silt curtain will be repaired immediately. Where the damage / fault is minor, the Contractor will undertake in-situ maintenance and repair by qualified divers without the need for retracting the silt curtain. Where such in-situ maintenance and repair are conducted, the Contractor will ensure that another diver is on standby, the appropriate warning flags / signals are in place, and the captain or foreman of the maintenance / construction vessel has communication channels open and ready to promptly alert other vessels to avoid the affected silt curtain area during the maintenance and repair. In case of mud plume flowing out from the silt curtain causing by the works is observed, repairing of silt curtain will be carried out immediately prior to resume the relevant marine works.

Spare parts of silt curtain will be prepared and stored on-site for replacement / repair. Where the damage / fault is extensive or cannot be easily repaired in-situ, the Contractor will retrieve the silt curtain and replace with new ones. In such circumstances, the relevant marine works will be suspended until the replacement is done.

4.5 Removal of Silt Curtain

Prior to removal of silt curtains, ensure all marine works and associated works (as mentioned in section 4.2 above) within the silt curtain has completed and visual inspection of the water quality shall be conducted to confirm no sediment plume remaining within the works area before commencing silt curtain removal. The silt curtain will be lifted carefully to avoid stirring up the seabed and will be removing by a crawler crane.

5 REGULAR CHECKING AND MONITORING

5.1 Inspection

Regular checking of the silt curtain will be conducted throughout the deployment of the silt curtain. The two types of checks that will be conducted are:

● Visual – the Contractor to check that the silt curtains are maintained in the correct positions with no obvious defects / entanglement, the marker buoys / lights (where applicable) are present and operational, and there is no observable muddy water passing through the silt curtain system. Any floating refuse trapped by the silt curtain will also be removed as part of the visual inspection.

● Diver – for conducting more thorough underwater inspections to check that the silt curtain fabric is intact, the silt curtain depths are correct, and there is no damage / breakage in load lines.

The checking frequency is summarised in Table 5.1. All checks will follow the inspection checklists shown in Appendix D and will be appropriately signed off by the Contractor.

Table 5.1: Inspection Requirement and Frequency

Inspection Requirement	Purpose	Visual Inspection Frequency	Diver Inspection Frequency
Upon initial installation	To confirm the silt curtain has been properly installed	Daily	Once
During operation	To maintain regular check of silt curtain performance / integrity		Quarterly
When there is observed / suspected sediment release	To identify cause of sediment release and confirm any remedial actions taken		At least once for each instance
Upon re-installation (where applicable)	To confirm the silt curtain has been properly re-installed		Once for each instance of re-installation

Weekly and ad hoc site inspections carried out by the Environmental Team (ET), and also monthly site inspection conducted by the Independent Environmental Checker (IEC), will include visual checks on the silt curtain location and effectiveness. Where the silt curtains deployed are identified by the ET and / or IEC to be ineffective or inadequate for controlling sediment release, the Contractor will make appropriate adjustments or provided additional silt curtains as necessary to improve and meet the water quality requirements of the Project.

5.2 Record Keeping

All inspections carried out by the Contractor will be recorded on the silt curtain inspection checklists are shown in Appendix D. All checklists will be signed by the Contractor and kept on-board the responsible maintenance / construction vessel and made available to the ET and IEC upon request for checking and auditing purpose. Diver inspection records will also be signed by the qualified diver. A summary of the records of the daily visual and the diver inspections including photographic records, as well as any rectification action taken, will be included in the Contractor’s monthly environmental reports.

An implementation schedule of key requirement of relevant mitigation measures is provided in Appendix E.

APPENDIX A

CONSTRUCTION PROGRAMME INVOLVING DEPLOYMENT OF SILT CURTAIN