The Chairman welcomed Members to the first meeting under the new term of service.
Agenda Item 1 : Confirmation of Minutes of 65th Meeting held on 26 November 2001
2. The minutes were confirmed without amendments.
Agenda Item 2 : Matters Arising
Para. 25: Para. 27 of EIAO GN006/2001
3. The Chairman informed Members that taking into account their views on the Guidance Note on "Some observations on ecological assessment from the EIA Ordinance perspective", the Note was finalized and issued together with seven other Notes. Copies had been circulated to Members.
Para. 28: Discussion with the Hong Kong Construction Association
4. The Chairman reported that the Secretariat would liaise with the Association to fix a date for meeting the Subcommittee.
Para. 32: Requests for more information about the KCRC on Spur Line
5. Members noted that the information requested had been provided by KCRC and sent to them on 12 December 2001.
Schedule of Meetings of the Subcommittee in 2002
6. The Chairman informed Members that the schedule had been revised to tie in with the meeting schedule of the full Council endorsed on 21 January 2002. Members endorsed the Subcommittee meeting schedule for 2002.
7. The Chairman informed Members that as he was one of the witnesses of the appeal arising from the previous EIA on the Spur Line, he preferred not to chair the discussion on agenda item 3. He then handed over the chair to Mr. Otto Poon, the Deputy Chairman, at that juncture.
Agenda Item 3 : KCRC East Rail Extensions - Sheung Shui to Lok Ma Chau Spur Line
(ACE-EIA Paper 1/2002)
8. The Acting Chairman welcomed the presentation team to the meeting. Mr. James Blake said that the EIA study which included the work of the previous EIA was a new one for the project. One of the major concerns of the current EIA was the hydrological impact on Long Valley arising from the tunnel option. He then asked Mr. Vic McNally to present the key issues and findings of the EIA study.
Hydrological impact assessment
9. A Member queried the soundness of the SEEP/W model that was adopted to study the impact of the tunnel on the groundwater system of Long Valley and the adequacy of groundwater monitoring by installing five peizometers at each of the four sections within Long Valley. She pointed out that the allowable fluctuations of the monitoring parameters had not been specified in the report. She doubted the effectiveness of the action plan to deal with possible changes in the groundwater regime. She also pointed out the absence of trials to validate the predictions of the hydrological models in groundwater movements and surface settlement.
10. In response, Mr. Richard Deacon said that the SEEP/W model was a commonly used 2-Dimensional model to analyze groundwater movement and pore-water pressure distribution within porous materials. The groundwater movement in Long Valley was modeled and compared. It was found that the underground water movement was dominated by the main aquifer. As the tunnel would be located in the much less permeable "Completely Decomposed Tuff' layer underneath the aquifer, the construction of the tunnel and the future operation of the railway would unlikely affect the groundwater movement. The results of the analysis showed that the groundwater table remained unchanged with or without the tunnel except for a 10mm variation at a section north of the tunnel alignment, but the variation was considered negligible.
11. On groundwater monitoring by piezometers, Mr. Deacon assured Members that data obtained by the four suites of peizometers at sections within Long Valley would be sufficient to characterize the groundwater table along the tunnel alignment. As regards the action plan, Mr. Deacon said that surface settlements arising from the passage of the tunnel-boring machine would unlikely affect the surface hydrology and in any case, the contractor together with local farmers could readily recover the situation. Ground water augmentation actions would be taken to restore the normal water level when the piezometer readings reached 300mm above the lowest level for Neap tide dry season. If those actions could not achieve the minimum groundwater level, a backup action would be to raise the downstream fabridam operated by the Water Services Department to impound the River Beas River Sutlej thereby flooding the alluvial aquifer across the Long Valley floor.
12. On the question of trials, Mr. McNally said that the best trial was the Tsing Tsuen Tunnel which was constructed by the same construction method and in soil conditions much more difficult than those in Long Valley and which had proved to be highly successful. 16mm of surface settlement was recorded and the water table had not changed. In response to a follow-up question by a Member, Mr. Jayananda Jesudason said that the predicted settlement in the Tsing Tsuen Tunnel was below 25mm.
13. In reply to a Member's question about settlement markers, Mr. Deacon assured Members that the number of markers would be adequate to monitor any surface settlement.
14. The Acting Chairman asked whether the vent holes of the ventilation system of the twin tunnels would affect the groundwater table. In response, Mr. Blake said that there were no ventilation holes along the tunnels. Instead the ventilation structures would be at the two ends of the tunnels.
15. A Member noted in para. 3.4.10 on P.3-10 of the EIA report that the baseline for groundwater level of a wet season Spring tide event had been obtained but an additional definitive dry-season record had yet to be run. He asked how the modeling results would be affected by incomplete baseline data. In response, Mr. Deacon said that the Neap and Spring tide data was presented in the EIA report. Further, both the wet season and dry season piezometric data showed a significant tidal influence in the Long Valley groundwater regime. The monitoring would continue during the project implementation stage.
16. A Member asked whether the tidal water would affect the water quality of the groundwater in the valley. Mr. Deacon replied that the salinity of the groundwater In Long Valley was similar to tap water which would not have any adverse impact on the habitats in that area.
17. A Member asked whether there was any possibility that the groundwater would be contaminated by the construction materials. In response, Mr. Jesudason confirmed that the tunnel boring machine would only use a biodegradable and non-toxic foam to facilitate the breaking down of materials during the tunneling operation. The foam had been tested and used in the Tsing Tsuen Tunnel and would not contaminate the groundwater.
18. A Member enquired about the worst-case scenario on the groundwater table during the construction period. In response, Mr. McNally said that the EIA was conducted based on the worst-case scenario. In fact, the impacts on the groundwater table arising from the operation of the railway were of greater concern than during construction.
19. A Member enquired about the rectification actions that would be taken if the actual change in groundwater level was more than 10mm. Mr. McNally said that the tidal effect was in fact much greater than the impacts arising from the construction works or the operation of the railway. The contractor would ensure that the changes in the groundwater level would stay within the normal groundwater regime.
20. The Acting Chairman asked whether there would be sufficient water in the rivers in all weather conditions to maintain the ecological value and agricultural value of Long Valley. In reply, Mr. Deacon said that the irrigation system which was operated by AFCD would bring water to the rivers all year round.
21. The Acting Chairman asked about the contingency plan to repair the tunnel and restore the hydrology of the area in case there was a crack in the "tuff" layer. In response, Mr. McNally said that they would repair it immediately as the tunnel must be kept dry in order to operate safely.
Baseline surveys of species of ecological importance
22. A Member referred to Table 4.2 on P. 4-13 and 4-14 of the report and queried why the butterflies identified in the ERM report were not found in the baseline surveys for the project. In reply,
Dr. Michael Leven explained that though the ERM Report was published in 1999, the list of rare butterflies was derived from a review of published and unpublished records. Those records were collected over 20 years ago and the woodland habitat concerned had degraded since that time. Hence those butterfly species were considered to be no longer present. The current EIA had adopted the results of the recent baseline survey as the basis.
Compensation by area or function 23. A Member said that while he realized that the ecological impacts arising from the construction of the station in Lok Ma Chau could not be avoided, ideally compensation should be made in terms of area as well as function. He asked whether it was possible to get more land to compensate for the loss of 9.1 hectares of fishponds. In response, Mr. McNally said that they had explored the Lok Ma Chau area to provide on-site mitigation. As the entire Lok Ma Chau area comprised fish ponds, there was no more land available for conversion to new fish ponds, and therefore the EIA report recommended compensating the loss of fishponds by enhancing the ecological functions of 27.1 hectares of existing fishponds in the same area. In response to that Member's enquiry, Mr. McNally said that the existing fishponds were granted by the Government.
24. Noting in the EIA report that there was problem in establishing a reliable and realistic baseline for habitat monitoring programme (ref. P.4-92 of the report), a Member expressed concern about the effectiveness of the proposed mitigation measures. Another Member asked whether off-site compensation had been considered. In response, Mr. McNally said that according to the Technical Memorandum (TM) on the EIA process, "either the same kinds of species or habitats of the same size shall be compensated, or the project proponent shall demonstrate that the same kind of ecological function and capacity can be achieved through the measures to compensate for the ecological impacts off-site"; and ecological mitigation measures shall be provided only if all practical on-site ecological mitigation measures had been exhausted. They had demonstrated in the EIA report that compensation could be achieved by enhancing the ecological function and capacity of the fishponds. Mr. Blake said that they had already complied with the requirements set out in the EIA Ordinance and the TM and it was beyond their remit to obtain more land for compensation. The second Member noted that since the TM stipulated that "...the project proponent shall demonstrate", the onus would be on KCRC to provide sufficient evidence that "demonstrated" the effectiveness of the proposed measures. Further since this was the first EIA report to be submitted under the EIAO that proposed mitigation by functional enhancement, she urged the Subcommittee to carefully scrutinize the mitigation proposals as the standard used would be precedent-setting.
Definitions of ecological function and capacity
25. A Member exchanged views with the project proponent regarding the definition of "ecological function and capacity". Dr. Leven said that in the current project the ecological function of the habitat concerned laid in its being used as commercial fishponds and the ecological capacity was assessed in terms of the wildlife that the habitat supported, i.e. the species of ecological importance as identified in the EIA.
26. A Member considered the definitions adopted by the proponent too narrow. She quoted that the Ramsar Convention defined ecological function as "activities or actions which occur naturally in wetlands as a project of the interactions between the ecosystem structure and processes" and wetland function as "processes among and within the various biological, chemical and physical components of a wetland, such as nutrient cycling, biological productivity, etc.". She said that the Canadian Government, European Union and Conservation International had their own definitions. In the local context, the Fish Pond Study stated that "the ecological value of a habitat is defined as its contribution in sustaining wildlife communities and essential ecological processes of a wider eco-system." Also the Oxford Concise Dictionary of Ecology defined "carrying capacity" as "the saturation value for species population showing the sigmoid shape population growth curve."
27. Dr. Leven said that the ecological value of the commercial fishponds laid in its being a source of food to certain species of water birds and an important foraging habitat for those birds. "Carrying capacity" was regarded as the maximum number of individuals that could be supported on a given area of habitat. To this end, the proposed compensation measures were to enhance the existing 27.1 hectares of fishponds by raising their carrying capacity for target species and hence their ecological value. The objective was to achieve an increase in bird usage by enhancing the ecological functions of the fishponds concerned during construction and after the completion of the project on a long-term basis.
28. A Member said that at present the ecological value of the commercial fishponds varied with the changes in fish farming activities which were affected by market demand. He asked whether the proponent had a detailed plan to ensure the productivity of fish in the fishponds concerned so as to achieve the target value. In response, Dr. Leven said that they had a detailed management plan for the enhanced fishponds to ensure that the birds affected would continue to use the area.
Adequacy and effectiveness of enhancement measures
29. The Acting Chairman asked why the proponent had adopted an enhancement factor of two for compensating the fishponds. A Member followed up on the Acting Chairman's question and pointed out that the usual enhancement factor in overseas countries was three. He asked for the justification for adopting a factor of two. In reply, Mr. McNally said that the factor was chosen in order to achieve a one to one compensation of the overall functional value of the fishponds. Dr. Leven supplemented that fishponds were easy to manipulate when compared to other habitats because they were artificial wetlands. In the present case, the input would include providing fish stock, maintaining shallow water, the pH value and water quality, and ensuring that the edges of the bunds would provide the right mixture of covered and open area for roosting of target bird species, etc.
30. In reply to a Member's enquiry, Dr. Leven replied that in calculating the carrying capacity of the fishponds, they had adopted the number of bird-days per pond as the unit. For example, based on observations conducted during the study, the average number of Black-faced Spoonbills supported by a typical fish pond at Pak Hok Chau Fishpond in winter was 17 bird-days.
31. Disregarding theoretical calculations, the Acting Chairman asked how the proponent could ensure the effectiveness of the proposed enhancement measures. In response, Mr. McNally informed Members that in the last two and a half months, they were carrying out experiments in the fishponds at Lok Ma Chau by controlling the water level and stocking of fish. According to the findings, the enhancement ratio was more than two (Annex I). As satisfactory results were obtained by carrying out only some of the proposed enhancement measures in the experiment, he was confident that the full enhancement programme would achieve, if not exceed, the intended results.
32. A Member said that the result of stocking fish in the Mai Po Nature Reserve Centre for the Great Cormorants was only for redistributing the bird population among different ponds rather than enhancing the number of birds in that area. In response, Dr. Leven said that under the EIA Ordinance and the TM, the proponent was only required to assess the impacts and compensate for the residual impacts of the project, not to ensure the eco-system of the whole region. Mr. Paul Tang said that the proponent was only required to demonstrate the effectiveness of the proposed mitigation measures but not obligated to manage the environment of the whole region.