Advisory Council on the Environment

Report on the 74th Environmental Impact Assessment Subcommittee Meeting

(ACE Paper 29/2002)
For advice


At its meeting held on 30 September 2002, the Environmental Impact Assessment (EIA) Subcommittee considered EIA report on the following projects -

  1. Ngong Ping Sewage Treatment Works and Sewerage;
  2. Shenzhen Western Corridor (SWC); and
  3. Construction of Lung Kwu Chau jetty.


2. Members are requested to advise whether the three EIA reports should be endorsed.


EIA report on Ngong Ping Sewage Treatment Works and Sewerage
(ACE-EIA Paper 16/2002)

Need for the project

3. At present, sewage generated in Ngong Ping area is treated by grease traps and septic tanks and then discharged locally as soakaways. Having regard to the increased number of visitors to Ngong Ping in recent years and the forecasted growth in visitors after the operation of the Tung Chung Cable Car system, the existing sewage treatment and disposal facilities will be inadequate. The proposed project will provide a centralized sewage treatment system and a local sewerage system for Ngong Ping.

Description of the project

4. The proposed project will include a sewage treatment plant providing biological and tertiary treatment with disinfection to the sewage collected, a trunk sewer and connection sewers, an effluent export pipeline to Tai O for discharge of the treated effluent and a new sewage collection network serving the unsewered village premises in Ngong Ping area. The proposed project is a designated project under the EIA Ordinance. Construction of the project will start in 2003 and will be completed in 2005.

Views and recommendations of EIA Subcommittee

5. Some Members had raised questions on whether the Tai O option for discharge of the treated effluent was better than the Tung Wan option which was shorter in length and hence required less excavation. Members' concerns on the project are mainly the comparison of the Tai O and Tung Wan options in terms of the amount of construction and demolition (C&D) materials generated; risk assessment of the Tung Wan option; impact of the Tung Wan option on gazetted beaches in Cheung Sha and Tong Fuk; submarine outfall for the Tai O option; impact on water sensitive receivers at Tai O and re-use of the treated effluent.

Construction and demolition waste to be generated

6. The project proponent advised that according to their latest estimation, the Tai O and Tung Wan options would generate about the 48,500 m3 and 47,000 m3 of C&D materials respectively. The project proponent was liaising closely with the Civil Engineering Department (CED) for identification of suitable disposal sites for the C&D materials. They would submit a plan on the minimization and management of C&D materials to CED for approval.

Risk assessment of the Tung Wan option

7. The project proponent explained that the Tung Wan option was considered a less preferable option because the effluent export pipeline would be too close to the Shek Pik reservoir and therefore there were concerns on the effect of any leakage or bursting of the pipeline on the waters of the reservoir. If, however, that there were effective measures to guarantee the safety of the pipeline and the risks concerned were acceptable, the project proponent would not preclude the possibility of adopting the Tung Wan option for the project.

8. The project proponent was discussing with the Water Supplies Department on mitigation measures for the Tung Wan option such as the laying of twin pipes and putting in place a full monitoring system. A risk assessment was being conducted on the basis of those mitigation measures to see if the risks of pipeline leakage or bursting could be controlled to within acceptable level. The risk assessment would be completed towards the end of November 2002. Impact of the Tung Wan option on gazetted beaches in Cheung Sha and Tong Fuk 9. The project proponent pointed out that the discharge point of the Tung Wan option was not near to the gazetted beaches in Cheung Sha and Tong Fuk and would not cause unacceptable impact on the water quality of the beaches. An additional water quality assessment being conducted for the Tung Wan option would look into that point to ensure that the problem would not exist.

Submarine outfall for the Tai O option

10. A Member suggested building a submarine outfall for the Tai O option. A longer submarine outfall would alleviate the concerns of the Tai O residents and remove the potential problem of siltation at the Tai O Creek in the longer term. The project proponent pointed out that there was about 30 m thick mud layer containing contaminated mud at the mouth of the Tai O Creek. The building of a submarine outfall would involve dredging of contaminated mud which would cause adverse impacts on the environment.

Impact on water sensitive receivers at Tai O

11. Members noted that the impacts on water sensitive receivers at Tai O including the seashore restaurants had been assessed and other developments at Tai O had been taken into account in the assessment. Members also noted that the Director of Drainage Services had given assurance to Tai O residents and restaurant operators that the discharge of the treated effluent would stop at times of high tides or flooding. The effluent would be temporarily stored in an emergency storage tank and discharge would resume after the tides/flooding had receded.

Re-use of the treated effluent

12. On the re-use of the treated effluent, the project proponent indicated that the subject which was outside the scope of the project was being dealt with separately by the Administration. An inter-departmental working group had been set up with partnership of the Mass Transport Railways Corporation (MTRC). The MTRC was interested in using the treated effluent in the Cable Car project but details had yet to be developed. The most promising usage would be for flushing purpose which would use up to 200 to 400 m3 of treated effluent per day. Irrigation was another possible usage but would require further investigation.

13. It was also suggested that the treated effluent, if not re-used as proposed by Members, could be discharged to the saltpans to be created in Tai O for the replanting of mangrove. The unsalted nature of the treated effluent would be beneficial for the growth of mangrove. It was, however, noted that the proposal would trespass private land and might affect the ecology of the Leung Uk Marsh.

14. Members reminded the project proponent not to over-design the pipeline if the treated effluent was to be re-used. The project proponent explained that the proposed pipeline was the minimum in terms of size. Even with the re-use of the treated effluent, the scope for reducing the size of the pipes would not be much.


15. Members considered both the Tai O and Tung Wan options were acceptable options with preference over the latter option subject to no adverse impacts on the water quality of beaches on Lantau South and the satisfactory result of the risk assessment of that option and the submission of the risk assessment report to the EIA Subcommittee at a later stage.

16. The Subcommittee emphasized that it was a golden opportunity for the Administration to demonstrate its commitment to sustainable development by making use of the treated effluent of the project for various purposes suggested.

17. The project proponent agreed that if the Tai O option was to be adopted, it had no objection to discharging part of the treated effluent to the Tai O saltpans on the understanding that it would not delay the project and subject to no adverse impact to the ecology of Leung Uk Marsh and the sorting out of the land issue.

EIA report on Shenzhen Western Corridor
(ACE-EIA Paper 17/2002)

Need for the project

18. The existing three vehicular boundary crossings between Hong Kong and Shenzhen are nearly saturated. To relief congestion at the existing crossings and to cope with the expected growth in cross-boundary traffic, the Hong Kong and Shenzhen governments jointly proposed to provide a fourth vehicular boundary crossing between the western districts of the two cities.

Description of the project

19. The proposed SWC is a dual 3-lane highway spanning across Deep Bay linking Donjiaotou in Shekou and Ngau Hom Shek in the New Territories of Hong Kong. The highway will be in the form of an elevated bridge of about 5.1 km long. 3.2 km of the bridge within Hong Kong waters will be provided under this project and connected to the local highway network via the future Deep Bay Link. The proposed project is a designated project under the EIA Ordinance. Construction of the project is scheduled to commence in 2003 for road opening by the end of 2005.

Views and recommendations of EIA Subcommittee

20. Members' concerns on the project were related mainly to the separate submission of the EIA report on Deep Bay Link and SWC; the interface with the Shenzhen side over the project; sighting of the EIA report prepared by the Shenzhen side; joint EM&A and arbitration mechanism; future management of the bridge; impact on birds during the construction phase; clearance of the oyster bed; traffic planning and management; lighting of the bridge and sedimentation monitoring. As a related subject, some Members specifically expressed concern about the impacts of major transport infrastructure on the environment and the effectiveness of the existing EIA mechanism in identifying such impacts.

Provision of public transport services and the EIA mechanism

21. Members felt that it was clear that the SWC project, like other major transport infrastructural projects, would affect the environment of Hong Kong particularly the air quality. Yet the project had complied with all relevant requirements under the EIA Ordinance and the Technical Memorandum, including the Air Quality Objectives. Having regard to the public concern on the very high level air pollution index recorded in the past few weeks, some Members were uncomfortable about the limitation of the existing EIA mechanism in identifying the adverse impact of designated road projects on air quality. A Member was also concerned about the difference in fuel types and standards between Hong Kong and the Mainland and its effect on Hong Kong's air quality. Since those issues are outside the scope of the project, Members suggested that they should revisit the Third Comprehensive Transport Study which provided basis for the long-term development of transport infrastructures in Hong Kong and their concerns should be brought to the attention of the Secretary for the Environment, Transport and Works and for discussion at the Council.

Submission of the EIA report on Deep Bay Link and Shenzhen Western Corridor

22. Members expressed concern that the EIA reports on Deep Bay Link and Shenzhen Western Corridor were submitted separately despite the fact that they were directly linked and that there were common mitigation measures. Members wished to alert the Administration that such practice should be avoided in future. The project proponent team clarified that because the time requirement of the two projects were different due to land resumption reason, it was necessary for the EIA process of the Deep Bay Link project to proceed first.

Interface with the Shenzhen side

23. Some Members regretted that despite the precedent of a joint EIA for the Shenzhen River Regulation Programme, it was not possible to have a joint EIA for the present project. The project proponent team clarified that the nature of the two projects were different, and that the current submission had taken into account the cumulative impact of the whole SWC project including the Shenzhen portion and other planned development affecting the study area. Although the two sides worked independently on the EIA report, they proceeded in close cooperation and regular liaison with a common objective to implement an environmentally friendly project. The cooperation and the interface with the Shenzhen side during the planning stage would continue during the construction and operation phases.

Sight of the EIA report of the Shenzhen side

24. On the possibility of having sight of the EIA report prepared by the Shenzhen side for information purpose, the project proponent team pointed out that it was not the normal practice of the Shenzhen government to release EIA reports for public inspection. Nonetheless, the Shenzhen side had agreed to make available a copy of the Executive Summary of the EIA report for sighting by interested parties in Hong Kong. The project proponent team would follow up with the Subcommittee in due course.

Joint EM&A and arbitration mechanism

25. On whether there would be joint EM&A and a mechanism to deal with the variance of mitigation measures of the two sides, the project proponent team indicated that the two sides would carry out EM&A work according to their respective standards and requirements. In the event that joint actions were required, the two sides would work through the liaison channel to discuss how to implement those actions. They had not gone so far as the arbitration mechanism but they would discuss as to how they would deal with disputes in future.

Future management of the bridge

26. On the future management of the bridge, the project proponent team pointed out that the subject had to be looked at realistically since the two sides did not have authority over the other on issues outside their respective boundary. Hence, the bridge would be managed by the two sides within their own boundary with perhaps the same management company working for them. The project proponent team assured Members that there would be close communications between the two sides to ensure that the bridge would be well managed irrespective whether the future management would be by the two sides or only one side.

Impact on birds during construction phase

27. On construction impact on birds particularly the Black-faced Spoonbills, the project proponent team indicated that according to the experience of the construction of the Cologne-Taipa Bridge in Macau, the population of the Black-faced Spoonbills remained steady during construction. It was a source of concrete evidence that the species were not affected by construction activities. Furthermore, it was noted that in Macau an operating landfill was adjacent to the foraging areas of the birds in the vicinity of the bridge with lots of human and mechanized activities going on. Nonetheless, the birds did not seem to react to those disturbances.

Clearance of the oyster bed

28. Regarding the lack of assessment of the impact caused by the clearance of the oyster bed, the project proponent team explained that the clearance would be done manually and no adverse impact was envisaged. As regards the future of the area after clearance, the project proponent team pointed out that the Lands Department which was responsible for granting oyster bed tenancy on a yearly basis had notified the tenant concerned in mid 2002 that the tenancy for the bridge area would terminate at the end of the year and would not be renewed. The long-term management of the area would be a separate issue outside the scope of the project.

Traffic management and planning

29. On traffic management of the SWC which was designed as a free flow highway, the project proponent team pointed out that both the Hong Kong and Shenzhen checkpoints would be on the Shenzhen side where there were sufficient vehicle holding areas and queuing spaces. The congestion now experienced in the three boundary crossings would not exist in the foreseeable future. There would be sufficient capacity to accommodate traffic flow coming out of SWC in the near term. In the longer term, other projects such as Route 10 and Tuen Mun by-pass were under planning to meet the demand of traffic growth after 2011. The overall traffic demand would be reviewed annually to determine the pace of the development of road projects under planning.


30. On the need to avoid excessive lighting for the bridge, the project proponent team clarified that there was no intention to light up the bridge in a prominent way since the objective was to minimize bird collision only. The lighting standards would make reference to relevant overseas practices and would be consistent for the whole bridge.

Sedimentation monitoring

31. On the reason why sedimentation monitoring was not proposed in the EIA report, the project proponent team explained that since the predicted increase in sedimentation rate of 0.5 mm per year near the Mai Po Ramsar Site due to the SWC was small compared with the current rate of about 16 to 28 mm per year, monitoring was considered not necessary. Furthermore, it would be very difficult to accurately identify and measure the sedimentation rate caused by the project because of the large number of factors that would lead to sedimentation in the region.

32. Since sedimentation might affect the mudflat and the eco-system in Deep Bay, the project proponent agreed after discussion to conduct monitoring on the sedimentation rate in Deep Bay during construction phase and for one year after the project had commenced operation.


33. Members recognized the difficulties of undertaking an EIA on a project involving two jurisdictions but nonetheless suggested the Administration, for future similar projects, to rigorously explore the possibility of conducting a joint study so as to minimize uncertainty and enhance effectiveness.

34. After further discussion, Members agreed that they would recommend the EIA report to the full Council for endorsement subject to the following conditions-

  1. the project proponent should monitor the sedimentation rate in Deep Bay area during the construction stage and up to one year after the project has commenced operation;
  2. the project proponent should regularly brief the Subcommittee on the progress of the environmental management of the project such as joint EM&A with the Mainland and lighting; and
  3. before the project commences operation the project proponent should provide to the Subcommittee a detailed emergency response plan on how to deal with incidents happening on either side of the bridge.

EIA report on Lung Kwu Chau jetty
(ACE-EIA Paper 18/2002)

Need for the project

35. The existing jetty at Lung Kwu Chau is ruined and not up to standard for berthing of vessels that transport equipment and personnel for servicing and maintaining Civil Aviation Department (CAD)'s Doppler VHF Omni-directional Range and Distance Measuring Equipment Station at Lung Kwu Chau. The Station provides tracked guidance on bearing and distance information to aircrafts using Chek Lap Kok Airport. At present, CAD relies on helicopter for transportation purpose which, however, is prohibited at night and during adverse weather conditions. To ensure that repairs could be made as and when necessary, construction of the jetty is required.

Description of the project

36. The proposed project comprises the construction of a precast concrete jetty and a concrete catwalk, dredging of an approach channel, installation of related facilities and demolition of the existing jetty.

Views and recommendations of the EIA Subcommittee

37. Having studied the EIA report and ACE-EIA Paper 18/2002, Members agreed that a presentation by the project proponent was not necessary and they would recommend the EIA report to the Council for endorsement subject to the condition that the project proponent would implement all mitigation measures stated in Tables 11.1 -11.4 of the EIA report and that future maintenance dredging during the operation of the jetty would avoid the peak season for Chinese White dolphins (May- August inclusive).

EIA Subcommittee Secretariat
October 2002




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