0 EXECUTIVE SUMMARY

Potential impact	Location	Type	Evaluation of impact
Habitat loss from construction operations	On-site	Direct	Few affected	Low	Mostly temporary (track on viaduct)	Reversible but regrowth is very slow	Low – moderate impact
Habitat fragmentation	Off-site	Indirect	Few affected	Low	Mostly temporary (track on viaduct)	Reversible but regrowth is very slow	Low impact
Disturbance of wildlife by noise and visual movement	Off-site	Indirect	Few affected	Very low	Mostly temporary (track on viaduct)	Reversible	Low impact
Dust deposition on surrounding habitats	Off-site	Indirect	None directly affected	Potentially a moderate area could be affected	Short and temporary	Reversible	Low impact
Increased sediment load in watercourses	Off-site	Indirect	None directly affected	Potentially a moderate area could be affected	Short and temporary	Reversible	Low - moderate impact
Pollution from toxic chemicals	On-site & Off-site	Direct & indirect	Few likely to be affected	Potentially a large area could be affected	Potentially long-lasting	Dependent on chemicals involved	Low impact
Soil compaction	On-site	Direct	None directly affected	Not quantified but probably moderate	Temporary	Mostly reversible	Low impact
Hydrological disruption	On-site	Direct	None directly affected	Not quantified but probably low	Mostly temporary	Mostly reversible	Low impact

Potential impact	Location	Type	Evaluation of impact
Habitat loss from construction operations	On-site	Direct	Few wet agricultural land species affected	Low	Mostly temporary	Reversible	Low impact
Habitat fragmentation	Off-site	Indirect	Very few wet agricultural land species affected	Low	Mostly temporary	Reversible	Low impact
Disturbance of wildlife by noise and visual movement	Off-site	Indirect	Few agricultural land species affected	Low	Mostly temporary	Reversible	Low impact
Dust deposition on surrounding habitats	Off-site	Indirect	Few wet agricultural land species (amphibians and invertebrates) may be affected	Potentially a large area Moderate area could be affected	Short and temporary	Reversible	Low impact
Increased sediment load in watercourses	Off-site	Indirect	Uncertain, amphibians and invertebrates most likely to be affected	Potentially a large area could be affected	Short and temporary	Reversible	Moderate impact
Pollution from toxic chemicals	On-site & Off-site	Direct & indirect	Potentially many species could be affected	Potentially a large area could be affected	Potentially long-lasting	Dependent on chemicals involved	Low impact
Soil compaction	On-site	Direct	Few wet agricultural land species affected	Low	Temporary	Mostly reversible	Low impact
Hydrological disruption	On-site & off-site	Direct	Few wet agricultural land species affected	Not quantified but probably low	Mostly temporary	Mostly reversible	Low impact

Potential impact	Location	Type	Evaluation of impact
Habitat loss from construction operations	On-site	Direct	Many wetland waterbirds affected	High	Mostly permanent due to station building	Reversible	Considerable ecological change
Habitat fragmentation	Off-site	Indirect	Many wetland waterbirds affected	Moderate	Mostly permanent due to station building	Reversible	Considerable ecological change
Disturbance of wildlife by noise and visual movement	Off-site	Indirect	Many wetland waterbirds affected	Large area affected	Mostly permanent due to station building	Reversible	High impacts
Dust deposition on surrounding habitats	Off-site	Indirect	None likely to be affected	Potentially a large area could be affected	Short and temporary	Reversible	Low impact
Increased sediment load in watercourses	Off-site	Indirect	None likely to be affected	Potentially a large area could be affected	Short and temporary	Reversible	Moderate impact
Pollution from toxic chemicals	On-site & Off-site	Direct & indirect	Potentially many species could be affected	Potentially a large area could be affected	Potentially long-lasting	Dependent on chemicals involved	Low impact
Soil compaction	On-site	Direct	None likely to be affected	Not quantified but probably moderate	Temporary	Mostly reversible	Low impact
Hydrological disruption	On-site & off-site	Direct	None likely to be affected	Not quantified but probably low	Mostly temporary	Mostly reversible	Low impact

Potential impact	Location	Type	Evaluation of impact
Habitat loss	On-site	Direct	Few species affected	Low	Permanent	Irreversible	Limited ecological change
Mortality from collisions with trains, buildings and other structures	On-site	Direct	Few species affected	Whole alignment and associated buildings potential hazard	Permanent	Irreversible	Very low impact
Habitat fragmentation	Off-site	Indirect	Few species affected	Low	Permanent	Reversible	Low impact
Disturbance of wildlife by noise and visual movement	Off-site	Indirect	Few affected	Not quantified but very low	Permanent	Reversible	Low impact
Pollution from toxic chemicals	On-site & Off-site	Direct & indirect	Potentially many species could be affected	Potentially a large area could be affected	Potentially long-lasting	Dependent on chemicals involved	Low impact
Hydrological disruption	On-site	Direct	None directly affected	Not quantified but probably very low	Permanent	Mostly reversible	Very low impact

Potential impact	Location	Type	Evaluation of impact
Habitat loss	On-site	Direct	Few wet agricultural land species affected	Low	Permanent	Irreversible	Low impact
Mortality from collisions with trains, buildings and other structures	On-site	Direct	Few wet agricultural land species affected	Low	Permanent	Irreversible	Very low impact
Habitat fragmentation	Off-site	Indirect	Few wet agricultural land species affected	Low	Permanent	Reversible	Low impact (track on viaduct)
Disturbance of wildlife by noise and visual movement	Off-site	Indirect	Few wet agricultural land species affected	Low	Permanent	Reversible	Low impact
Pollution from toxic chemicals	On-site & Off-site	Direct & indirect	Potentially many species could be affected	Potentially a moderate area could be affected	Potentially long-lasting	Dependent on chemicals involved	Low impact
Hydrological disruption	On-site & off-site	Direct	None directly affected	Not quantified but probably very low	Permanent	Mostly reversible	Very low impact

Potential impact	Location	Type	Evaluation of impact
Habitat loss	On-site	Direct	Many waterbird species affected	High	Permanent	Irreversible	Considerable ecological change
Mortality from collisions with trains, buildings and other structures	On-site	Direct	Potentially many Species of Conservation Importance	Track and station buildings potential hazard	Permanent	Irreversible	Low impact
Habitat fragmentation	Off-site	Indirect	Many waterbird species affected	Moderate	Permanent	Reversible	Moderate impact
Disturbance of wildlife by noise and visual movement	Off-site	Indirect	Many waterbird species affected	Large area affected	Permanent	Reversible	High impact
Pollution from toxic chemicals	On-site & Off-site	Direct & indirect	Potentially many species could be affected	Potentially a large area could be affected	Potentially long-lasting	Dependent on chemicals involved	Low impact
Hydrological disruption	On-site & off-site	Direct	None directly affected	Not quantified but probably very low	Permanent	Mostly reversible	Very low impact

4.8 Completed Projects with Mitigation Measures which may be Impacted by the Spur Line

4.8.1 The Shenzhen River Regulation Project Phase II included within the mitigation measures for adverse ecological effects, the requirement to reinstate ponds along the southern bank of the Shenzhen River at Lok Ma Chau. Some of these ponds fall within the proposed footprint of the station whilst others are adjacent to the proposed Lok Ma Chau mitigation area. No specific targets, either in terms of habitat enhancement or in terms of species, were included in these mitigation proposals (Peking University 1995). Accordingly, for the purposes of baseline assessment, it is assumed that the reinstated fishponds have an equivalent value to existing commercial fishponds.

4.8.2 These reinstated fishponds are considered to be within the disturbance zone of the border road for large waterbirds and have therefore not been included in the calculation of the area of direct habitat loss under the station, and the overall area of habitat required to be compensated for these species (section 4.11 of this chapter). However, theses reinstated fishponds are used by less disturbance sensitive species and have therefore been included in the consideration of habitat compensation requirements for these species (although the requirement overall is much smaller than for large waterbirds).The reinstated ponds to the west of the station, that are not directly impacted by the station footprint, have been excluded from the area proposed to be managed as a mitigation area for the station in order to ensure that conservation objectives for these ponds are not compromised.

4.9 Concurrent Projects with Potential for Cumulative Impacts

4.9.1 Table 4.38 lists major projects that will be conducted concurrently with the construction of the Spur Line. Each of these projects has the potential to impact the ecology within the Study Area. The locations of these projects in relation to the Spur Line Alignment are shown on Figure 2.3. Projects of particular significance, due to their proximity to the proposed Lok Ma Chau station, areconstruction of the San Tin Eastern Main Drainage Channel and expansion of the Lok Ma Chau Boundary Crossing. Since the NENT Study is still underway it is not known what, if any, effect the findings of this study will have upon the ecological resources of the Long Valley area.

4.9.2 The San Tin Eastern Main Drainage Channel which will be constructed to the west of the Lok Ma Chau Boundary Crossing will be crossed by the elevated section of the Spur Line. The section of the channel that will be impacted will have grasscrete banks and will include an adjoining area of managed wetland to be provided in mitigation for fishpond loss due to the channel construction. Direct impact due to the Spur Line at its crossing point will be the formation of one or possibly two pillars for the viaduct, resulting in direct loss of grasscrete bank and/or managed wetland of 25-50 square metres.

4.9.3 The habitat to be lost is stated in ERM (1999a) to be of moderate to high value for wetland dependent bird species, though the targeted species are not specified. Since this habitat is to be provided on approximately a 1:1 basis in compensation for fish pond loss (ERM 1999a), this direct loss is catered for within the requirement to mitigate for fish pond loss and in the wetland enhancement requirements specified later in this section. Since this area already suffers disturbance impacts as a consequence of the Boundary Crossing, there will be no additional disturbance impacts hence there is no requirement for disturbance impacts to be compensated..

4.9.4 Construction works for the San Tin Eastern Main Drainage Channel are likely to be concurrent with the Lok Ma Chau station site formation works. There is a small potential for a cumulative impact to occur. However, since the San Tin compensation wetlands are already within the disturbance zone of the Lok Ma Chau Boundary Crossing, the additional disturbance from Spur Line is minimal. Nevertheless, to counteract any minor additional impact, mitigation will be provided in the form of early compensation distant from the area of construction works. This will be achieved through the proposed mitigation measures detailed in the following sections. The Spur Line project is unique in that it provides for construction disturbance impacts in addition to long term habitat loss.

4.10 Possible Future Projects with Potential for Cumulative Impacts

4.10.1 Subsequent projects should avoid direct negative impacts on mitigation areas, temporary or permanent, that are already designated through this or any other project. This applies, in particular, to the proposed San Tin Western Drainage Channel. Should a decision be made to proceed with this project, there is potential for a cumulative impact with the Spur Line. The alignment and hydrological effects of the Drainage Channel must be designed so that they have no adverse effect on the proposed Lok Ma Chau Spur Line mitigation area and / or compensate for any direct or indirect adverse effects including disturbance and hydrological impacts during the construction period.

Table 4.38

Summary of Major Committed Projects Adjacent to the Spur Line

Project description and potential impacts	Commencement Date	Completion Date
*Shenzhen River Training Phase III* involves the realignment of the Shenzhen River to improve drainage efficiency and prevent flooding. Impacts include direct habitat loss and construction phase disturbance	Mid 2001	Late 2004
*San Tin Eastern Main Drainage Channels –* drainage improvement works to alleviate flooding in the San Tin area and provide flood storage ponds for Chau Tau and Pun Uk Tsuen. Impacts include direct habitat loss, fragmentation, and construction phase disturbance	September 2002	2005
*Fanling, Sheung Shui & Hinterland Main Drainage Channels* – drainage improvement works to alleviate flooding in the Fanling, Sheung Shui & Hinterland areas. Impacts include direct habitat loss, fragmentation, construction disturbance, and possible indirect loss of wetland habitat through lowering of water tables.	1999	2003
*Planning & Development Study* *on Northeast New Territories* involves examination of the scope and feasibility of accommodating strategic growth development needs in the NENT. Potential impacts include habitat loss, fragmentation, construction and operation phase disturbance.	Programme not yet confirmed	-
*Lok Ma Chau Control Point Expansion Project* – kiosk expansion and works to improve vehicle and passenger throughput and circulation. Impacts include direct habitat loss, construction phase disturbance	Mid 1999	2003

4.11 Mitigation Measures during Construction Phase

4.11.1 The measures detailed below are designed to minimise residual impacts of ecological resources and address the requirements of the Study Brief (Clause 3.5.2 (ix)).

Avoidance

4.11.2 The Spur Line alignment has been selected based on engineering, operational safety and environmental grounds. The rationale for the combination of a viaduct in the western section and a bored tunnel in the eastern section has been explained in Chapter 2 of this report Various options of the alignment were examined in detail from the environmental point of view, in the PPFS, the previous EIA study and were also considered by the Appeal Board. In this selected alignment, potential direct impacts on Long Valley have been considered. The potential impact on hydrology has also been minimized through the use of the Earth Pressure Balance mode of the Tunnel Boring Machine (TBM). More details of this mitigation and contingency plans to monitor groundwater levels in Long Valley are presented in Chapter 3, Hydrological Impacts Assessment.

4.11.3 The western end of the alignment passes through the Wetland Conservation Area (WCA), in which development is restricted, and where it does take place mitigation of ecological inputs must be fully implemented. The requirement for Lok Ma Chau Terminus to connect to Huanggang Station necessitates that the Terminus be located at the proposed site. Thus, potential impacts on WCA cannot be avoided, but are fully mitigated by the measures proposed in the current project. The principle of “no-net-loss in area” cannot be achieved as there is no additional physical area of land with the relevant substrate within the WCA that can be converted into fish ponds. However, the principle of “no-net-loss in function” has been fully addressed. Enhancement of existing fish ponds is proposed to provide additional effective habitat for target species. This is fully explained in subsequent sections. It is considered that the selected route minimises impacts on ecologically sensitive areas, while remaining within the constraints of other engineering and planning requirements.

Minimisation

4.11.4 Measures are proposed for the design and construction of the Spur Line project to minimise potential impacts on ecological resources. The station building will be designed in a manner that keeps disturbance of wildlife to an absolute minimum, including both noise and visual disturbance. Large areas of reflective material (including glass) should not be used on the outer surfaces of the building, as this in known to result in aerial collisions from birds. In terms of landscaping, little other than screen planting can be done to disguise the station from wildlife. The station height has been minimised within the constraints of the required function of the building.

4.11.5 The design of the pier footings of the footbridge will be carried out so as to minimize additional turbulence that may increase turbidity. Appropriate design will help prevent adverse impacts on the ecological resources of Deep Bay. Working practices using concrete should minimize the release of concrete washings into waterbodies, to prevent adverse impacts on downstream water quality and ecology.

4.11.6 Strict control of contractor access and access routes along the alignment will be implemented as an important measure to reduce disturbance. No contractor access will be allowed within Long Valley during the construction period other than by personnel taking routine readings of settlement markers and piezometers for groundwater. Works to be carried out on the east side of the River Sutlej and the west of the River Beas will be designed to minimize disturbance within Long Valley, through the use of measures described in the Noise Chapter of this report. Residences exist close to these works and a series of measures has been proposed to reduce noise levels to an acceptable level. These measures will also reduce impacts to ecological resources during construction.

4.11.7 A group of Fan Palms Livistonia chinensis on the proposed Spur Line alignment at Chau Tau has been identified as a roost for the Short-nosed Fruit Bat Cynopterus sphinx and as a possible roost for the little-known Lesser Club-footed Bat Tylonycteris pachypus. To minimize potential disturbance to these bats, it is proposed that the tunnel be driven from the east (at Sheung Shui) to the west (Chau Tau. The launching shaft will be located in the least sensitive area, while the much smaller area required for the recovery shaft will minimize disturbance to the bats. Since these trees and roost are over the tunnel section of the Spur Line (which will be sufficiently deep that palm roots will not be affected), direct impacts are avoided. However, minimisation of disturbance impacts arising from the construction of the tunnel portal should be avoided by controlling access to the roost location and screening it from construction noise, light and other forms of disturbance. A barrier should be erected around the contractor’s works area to minimise disturbance to the bat colony. The contractor’s access should be limited to the minimum area required and as far as possible from the bats’ location.

Habitat Loss and Disturbance

4.11.8 As described previously, the impacts of disturbance, though to a lesser extent, are analogous to habitat loss and therefore mitigation measures for these are treated together here. As summarised earlier, the main area of ecological importance that is subject to high levels of permanent habitat loss and disturbance impacts are the fishponds around the station complex at San Tin / Lok Ma Chau. Of secondary concern are impacts along the viaduct section of the Spur Line between Lok Ma Chau and Chau Tau. Ecological impacts along the tunnel section are almost entirely restricted to disturbance impacts during the construction period.

4.11.9 Disturbance during the construction phase should be minimized and controlled through a clear definition of the works areas for the contractor. The Scheme Boundary (shown in Figure 4.1 ) is the limit of resumption but does not necessary equate to the limit of the contractors’ access. For example, where the viaduct passes across fishponds east of the LMC Boundary Crossing, the contractors may need to drain each fishpond and construct a working bund on which to carry out piling works and pier construction. The width of the bund will become the Works Limit of the contractor. The Limit of Site will include the whole pond.

4.11.10 Disturbance to the bat colony will be minimized as mentioned above. The contractor will be required to erect a hoarding around the area required for construction of the TBM recovery shaft and will only be allowed to utilise land designated as his Works Area.

4.11.11 These conditions shall be included in the Contract Particular Specification and enforced by the Engineer or his representative.

4.11.12 Around the LMC Terminus, several contracts will interface and some of the designated works area may be for a temporary period, long enough to complete a piece of work before handing the site area to the next contractor. For example, the area to the south of the station is proposed as a marsh area (see next section on Habitat Compensation). This area will initially be filled to a specified level by the station contractor, who will then hand over the site to the contractor responsible for creating the overall ecological mitigation area. The sequence of station formation and wetland creation and the implications of disturbance from projects in the area are described later in this Chapter.

Habitat Compensation

4.11.13 As avoidance and minimisation measures are unable to fully mitigate for habitat loss and disturbance impacts then it is necessary to offset potential residual impacts through habitat compensation. The aim of habitat compensation will be to replace habitats of intrinsic ecological value and ecological functions for Species of Conservation Importance that will be lost or degraded. Compensation may be carried out through the enhancement of existing habitats (i.e. by raising the ecological value of the habitat and thereby its carrying capacity for target species) or by restoration or creation. As the only significant potential residual impacts will relate to habitat loss and disturbance in the area of fishponds around the station complex at Lok Ma Chau then compensation will be targeted towards this location and habitat and the associated Species of Conservation Importance (see Section 4.6 on the explanation for impacts to other habitats).

4.11.14 The area used for compensatory habitat provision will be as close as possible to the area where the impacts occur, whilst accommodating the requirement for some (at least) of the mitigation area to be remote from sources of disturbance which would reduce its value.

4.11.15 In developing the habitat compensation measures, both construction phase and operation phase disturbance were considered. It is important that some habitat mitigation measures are carried out as soon as possible in a location remote from disturbance impacts during the construction of the station. This is necessary to allow vegetation communities and associated animal communities to become established so that suitable habitat is available for displaced species when works commence. Accordingly, the habitat mitigation measures at Lok Ma Chau must be phased so that overall carrying capacity for Species of Conservation Importance is maintained throughout the construction period.

4.11.16 A group of ponds at the western section of the proposed mitigation area are 200 m to more than 500 m from the station works area and hence are beyond the predicted disturbance zone from the station construction for Species of Conservation Importance (see Table 4.28 and Figures 4.3 and 4.6). The measures to enhance these ponds should be in place before the start of site formation for the station complex. Those ponds will be capable of providing enhanced feeding opportunities by a combination of the provision of the new shallow margins, fish stocking and the lowering and management of water levels. Complete mitigation must be in place by the time the station becomes operational. The programme of implementation is defined in detail later in this section.

4.11.17 Principles for habitat compensation and designs for the Lok Ma Chau mitigation area are provided below, whilst further details of the proposed scheme (including management regime) are provided in the Draft Habitat Creation and Management Plan (Appendix A4.2 of this EIA Report). A final version of the Habitat and Creation and Management Plan will be prepared following approval of the EIA for the project. This final version will, therefore, be able to incorporate public or other comment that is generated by the examination of the EIA.

Compensation for the Loss and Disturbance of Fishpond Habitats Used by Bird Species in the Lok Ma Chau / San Tin Area

4.11.18 Compensation requirements must be calculated with reference to the existing functional value of the impacted area. In the case of Lok Ma Chau, the area to be impacted includes the station footprint and the area proposed for compensation (shown in Figure 4.5). As indicated in Table 4.27 the direct loss of fishponds in Lok Ma Chau Station area and along the viaduct, amounts to 9.6 ha. However, several of the fishponds within this area impacted by the station are very small and are located directly alongside the road along the boundary fence. These ponds, which occupy an area of 2.1 ha, are already heavily disturbed and are therefore considered to lie in the total exclusion zone as they are rarely used by large waterbirds. On the east side of the Lok Ma Chau Boundary Crossing 0.4 ha of fishponds will be directly impacted by the construction of an Emergency Access Point (EAP) below the viaduct. Evaluation of disturbance impacts from the viaduct has taken into account the disturbance zones already present due to the Lok Ma Chau Boundary Crossing. This was calculated with reference to the functional value of the current habitat (already disturbed) and the future value of this habitat (with Spur Line superimposed). The current functional value of the potentially impacted area (including the EAP) is 2.6 ha. The future functional value of the habitat with Spur Line present, is 0.7 ha. The disturbance impact from Spur Line viaduct therefore equals 1.9 ha. An additional 0.1 ha inactive fishponds at Chau Tau will also be impacted, but is within the 100 m disturbance zone of FanLing Highway and is therefore not utilised by large waterbirds. The total habitat area impacted through habitat loss at Lok Ma Chau station is therefore 9.2 – 2.1 – 0.1 ha = 7.0 ha. The area impacted through habitat loss and disturbance along the viaduct section of Spur Line is 2.6 ha.

4.11.19 In addition to the direct impact from the structures associated with Spur Line, there are secondary impacts associated with the implementation of the proposed mitigation measures. The compensation area that is available for mitigation (as shown in Figure 4.5) occupies 37 ha. The total functional value of the existing fishpond habitat that will potentially be impacted by Spur Line is therefore 7.0 + 2.6 + 37.0 ha = 46.6 ha.

4.11.20 In addition to the direct impacts and secondary impacts described above, impacts will also occur indirectly through disturbance. Whilst disturbance impacts affect most species, analysis of the susceptibility of Species of Conservation Importance to disturbance (as described above and shown in Table 4.28) demonstrates that the bird species most susceptible to disturbance are two species of large birds of prey, Imperial Eagle and Greater Spotted Eagle and four species of large waterbird, Great Cormorant, Grey Heron, Great Egret and Black-faced Spoonbill.

4.11.21 In the previous EIA Report (BBV 2000a) it was noted that Imperial Eagles and Greater Spotted Eagles range widely in the Deep Bay area and are known to exhibit marked avoidance of man-made structures. However, relatively little was known regarding the extent to which these species utilised the Lok Ma Chau area and hence there was considerable uncertainty regarding the scale of possible impacts and hence their importance. A subsequent study, conducted during winter 2000 to 2001 demonstrated that these eagles make little use of the Lok Ma Chau area with their distribution being concentrated in Mai Po Nature Reserve (Appendix A4.1). Mitigation of disturbance impacts on these species is not, therefore, a key concern though their requirements will still be taken into account in habitat creation proposals for the mitigation area.

4.11.22 Accordingly, the area required for mitigation of impacts at Lok Ma Chau is calculated based on the direct habitat loss and areas which are subject to disturbance impacts for the four large waterbirds (Great Cormorant, Grey Heron, Great Egret and Black-faced Spoonbill) which were recorded during the baseline survey as regularly utilising the area. If the requirement to compensate for the disturbance to these species is met, full compensation for the impacts of direct habitat loss and disturbance to less sensitive Species of Conservation Importance which also make use of the fish ponds (including the bunds) at Lok Ma Chau will also be achieved, so long as appropriate habitat is provided. As an example of this, the compensation requirements of less disturbance sensitive species have been considered. As stated earlier (section 4.8), the reinstated fishponds from the Shenzhen River Regulation project are used by less sensitive species, and have therefore been included in the habitat loss for these species. However, with minimal disturbance impacts from the station construction and operation to these species, the compensation requirement is simply the direct habitat loss i.e. 9.6ha (the station footprint) and 0.4ha (the loss of habitat as a result of the EAP construction beneath the viaduct). Thus, the proposed compensation can readily cover the requirements of these less sensitive species.

4.11.23 Calculation of the overall land requirement to compensate for direct habitat loss and disturbance effects for the large waterbirds is as follows:

· Land requirement to compensate for direct habitat loss

· Land requirement to compensate for exclusion zone around the station and the viaduct

· Land requirement to compensate for area of reduced density around the station and the viaduct

4.11.24 Exclusion zones and zones of reduced density are as detailed in Table 4.28. The required area to compensate for habitat loss in the zone of reduced density is 50% of the total area of the zone as is shown figuratively in Figure 4.4. As stated earlier, several small fish ponds close to the boundary fence are rarely used by large waterbirds and have therefore been excluded from the habitat impact calculation. The calculation also takes account of the disturbance zones from Lok Ma Chau Boundary Crossing. The areas calculated are shown in Figure 4.3.

4.11.25 In addition, the boundary from which exclusion and disturbance zones are taken differs between construction and operation. During construction, the boundary is taken as the edge of the station footprint, where ponds will be filled to form the station platform and the drainage channel will be formed. During operation, the feature that will create disturbance is the station building. The low-lying platform will have minimal impact and the channel should be designed to blend in with the surrounding area. These different zones during construction and operation are shown in Figures 4.10b (during construction) and 4.10c (during operation).

4.11.26 Land requirements for the four large waterbirds during construction and operation are derived as shown in Tables 4.39 and 40 respectively. Estimates of required compensation factors for disturbance impacts are based on the individual species assessment of sensitivity to disturbance discussed earlier and takes into account areas that are already subject to existing disturbance within the station complex area, e.g. the Boundary Crossing (Figure 4.3)

Table 4.39

Land requirement to compensate for habitat loss for

large waterbirds during construction stage

Species	Habitats utilised	Land requirement to compensate for direct habitat loss (ha)	Land requirement to compensate for disturbance exclusion zone (ha)	Land requirement to compensate for zone of reduced density (ha)	Total land requirement (ha)
Great Cormorant	Active & Inactive Fish ponds	7.0	9.85	3.7	20.55
Great Egret	Active & Inactive Fish ponds	7.0	9.85	6.7	23.55
Grey Heron	Active & Inactive Fish ponds	7.0	9.85	6.7	23.55
Black-faced Spoonbill	Active & Inactive Fish ponds	7.0	9.85	6.7	23.55

Note: In the following text, values will be rounded to 1 d.p.

Table 4.40

Land requirement to compensate for habitat loss for

large waterbirds during operation stage

Species	Habitats utilised	Land requirement to compensate for direct habitat loss (ha)	Land requirement to compensate for disturbance exclusion zone (ha)	Land requirement to compensate for zone of reduced density (ha)	Total land requirement (ha)
Great Cormorant	Active & Inactive Fish ponds	7.0	7.05	2.7	16.75
Great Egret	Active & Inactive Fish ponds	7.0	7.05	4.9	18.95
Grey Heron	Active & Inactive Fish ponds	7.0	7.05	4.9	18.95
Black-faced Spoonbill	Active & Inactive Fish ponds	7.0	7.05	4.9	18.95

Note: In the following text, values will be rounded to 1 d.p.

Construction Stage

4.11.27 The highest value calculated for the total land requirement is 23.6 ha. This is calculated from the habitat loss due to the station footprint, together with the exclusion zone during construction (up to 100 m) and a reduced density of birds in the disturbance zone (100 to 200 m) for the Lok Ma Chau terminus. The disturbance areas around the station are shown visually in Figure 4.10b. An additional 2.6 ha is impacted due to disturbance from the viaduct section of Spur Line east of Lok Ma Chau Boundary Crossing (taking into account the existing disturbance due to this major road).

4.11.28 Compensation will be provided before and during the construction phase to compensate for these direct and indirect impacts. This will be described later in this chapter (Section 4.12).

Operation Stage

4.11.29 The The main concern is the long-term operational impacts that must be met through a comprehensive compensation package. During operation, the disturbance zones are closer to the station because the main source of disturbance is the station building and not the low-lying platform. The zones of disturbance therefore retreat, as shown in Figure 4.10c.

4.11.30 The direct impact to the fishpond habitat remains the same as during the construction phase, i.e. 7.0 ha. The exclusion zone within 100 m of the station building occupies 5.8 ha and the disturbance zone from 100 to 200 m occupies 8.4 ha (at 50% impact this value is reduced to 4.2 ha). The area of disturbance impact due to the viaduct section of the Spur Line is 1.9 ha, less than for the construction phase because the fishponds affected will be reinstated. The total habitat loss during operation phase is therefore 19.0 ha.

Long–term Compensation for Habitat Losses

4.11.31 The proposed compensation area to meet this requirement is shown in Figure 4.6. The area available to compensate for fishponds directly and indirectly impacted comprises 27.1 ha.

4.11.32 A small area of fishponds (0.1 ha) lies within 100 m of the station building (the exclusion zone during operation) (Figure 4.10c) and residual disturbance from the station is expected to exclude large waterbirds from this area. This area is therefore excluded from the compensation calculation.

4.11.33 The area between the 100 m and 200 m zones from the station building amounts to 4.7 ha. Taking the precautionary approach, and using the same principles used for calculation of the compensation required, a reduced density of large waterbirds has been assumed for this area. The new functional value of this area prior to enhancement is calculated as half of the actual area, i.e. 2.4 ha. The remainder of the 27.1 ha is undisturbed and the functional value is taken to be equivalent to the area (22.3 ha).

4.11.34 The new functional value of the compensation area that is available for enhancement (expressed in area terms) is therefore 24.7 ha (22.3 + 2.4 ha). If this area is enhanced by a factor of 2, (i.e. a doubling of its functional value), the total functional value of the area is 49.3 ha. In addition, the remaining functional value of the fishponds alongside the viaduct east of the Lok Ma Chau Boundary Crossing totals 0.7 ha. the total functional value of the impacted area, after enhancement, is therefore 50.0 ha.

4.11.35 In summary, the loss of an area of 46.6 ha fishponds (see paragraph 4.11.18) will be compensated through provision of an area of 27.1 ha fishponds which, when enhanced by a factor of 2 (i.e. doubling) through measures described in this report, will enable an increase in functional value to 49.3 ha. Reinstatement of fishponds to the east of LMC Boundary Crossing will add a further 0.7 ha to this functional value, bringing the total to 50.0 ha. This is tabulated later in this chapter (Table 4.43 in section 4.12, in relation to the programme of enhancement).

4.11.36 The area proposed for compensation, if implemented in a timely manner to mitigate residual impacts during construction, will be adequate to provide compensation for the large waterbirds shown above and all other Species of Conservation Importance except for Greater Spotted Eagle and Imperial Eagle. As discussed above, these last two species are wide ranging raptors, wintering in the Deep Bay area and an intensive field survey during winter 2000 to 2001 showed that they made very little use of the Lok Ma Chau area. Thus, the impact resulting from loss of fishpond under this project will result in a relatively small direct loss of their habitat. This small direct habitat loss will, however, be compensated for in function as the survey also demonstrated that these species concentrated in managed wetland areas where large numbers of waterbirds (especially ducks) were present (Appendix A4.1). Habitat management measures to enhance the suitability of the area for ducks will, therefore, also enhance its suitability for these species.

4.11.37 These areas of 23.6 ha during construction and 19.0 ha during operation are largely included in the 46.6 ha. The difference between these values is that the 23.6 ha and 19.0 ha is based on direct loss and disturbance, whereas the 46.6 ha includes secondary impacts generated by the proposed enhancement of ponds for compensation (paragraph 4.11.18).

4.11.38 The required areas of approximately 23.6 ha during construction and 19.0 ha during operation have been derived from a consideration of compensation requirements for the species shown in Tables 4.39 and 4.40. As indicated in Table 4.28, other bird species of regular occurrence are less sensitive to disturbance. Compensation requirements for these other bird species of conservation importance will, therefore, be more than compensated within this defined area in accordance with the precautionary principle quoted in TPB PG No. 12B (1999).

4.11.39 Two important aspects of the effectiveness of implementation of the proposed compensation area are:

a) the measures to be used to achieve the enhancement of the compensation area; and

b) the timing of their implementation, particularly in relation to the construction works for Spur Line and possible disturbance impacts from other projects in the area.

4.11.40 The following sections describe details of the proposed compensation habitats to be created in the LMC Station area, and are followed by a description of the proposed programme of implementation to minimize residual impacts during construction.

4.11.41 The proposed compensation area of approximately 27.1 ha (enhanced functional value of 49.3 ha) is located in the fish pond area to the south and west of the station site (Figure 4.5). Since this area is already of ecological value, it is clearly necessary to enhance the carrying capacity of the wetland to meet the mitigation target. Overall the enhancement required is a doubling of the carrying capacity.

4.11.42 As explained in Section 4.4, the baseline value of the Lok Ma Chau fishpond area has been highly variable in terms of numbers of species over the most recent three winters. The baseline number of birds against which to compare the proposed compensation has therefore been estimated as the average number of birds per pond during the two winters of commercial fish farming activity (1998-99 and 1999-2000). Due to the highly temporal and unpredictable nature of predicting the number of birds on a particular pond, because of external factors such as the condition of surrounding ponds and the degree of disturbance in the area, alternative criteria are proposed for measuring the degree to which this doubling of capacity has been achieved.

4.11.43 A range of options for wetland enhancement to achieve the necessary overall doubling in capacity of the wetland have been investigated and considered in respect of the following criteria:

• Technical feasibility for provision in the context of physical features of the area.

• Compatibility with existing and surrounding land uses.

• Potential carrying capacity for target Species of Conservation Importance of different wetland habitat types.

• Potential scope for provision for other wetland Species of Conservation Importance.

• Compatibility with habitat creation requirements for other purposes (e.g. screening of the station).

• Requirement to avoid areas adversely impacted by existing or proposed developments.

4.11.44 Based on these criteria, it is considered that the most appropriate design for compensatory provision is the enhancement of fish ponds. Currently the large biogeographically important populations of herons and egrets that use fish ponds in the Deep Bay area primarily feed on the abundant small non-commercial fish and invertebrates (termed ‘trash fish’) that thrive as a by-product of the highly productive commercial fish-farming systems. These include Gambusia affinis (Mosquito Fish), Macrobrachium nipponense (a prawn) and Oreochromis mossambicus (a species of tilapia).

4.11.45 However, these food resources are generally only readily available to birds when the ponds are drained down for fish harvesting during the winter. Furthermore, only a small proportion of fish ponds are drained at one time and only for short periods. Consequently, a large area of fish ponds is required to support the bird populations and avoid ‘feeding bottlenecks’.

4.11.46 The spatial distribution of birds feeding on ponds is highly dynamic and variable as birds move between fish ponds as they are drained. When recently drained, such fish ponds may contain many hundreds of feeding egrets, herons and other waterbirds. Furthermore, recent evidence (collected during the baseline survey) demonstrated that drained-down commercial ponds within the Lok Ma Chau area could be very attractive to Black-faced Spoonbills, a Globally Endangered species. In Hong Kong, Black-faced Spoonbills feed largely in intertidal mudflat areas (WWF 2001). However, the expanding population also makes opportunistic use of drained-down ponds (WWF 2001, AEC 2001) and, whilst this habitat is probably of secondary importance for the species, it may be valuable in late winter (in particular) when food resources in intertidal mudflats are at a low level.

4.11.47 When ponds are full, their use by birds is severely limited due to their relatively steep sides, deep water and their frequent lack of marginal vegetation. These characteristics also limit their biodiversity interest for other taxa groups. The main objective of enhancing fish ponds would therefore be to:

• Increase the value of fish ponds to Black-faced Spoonbills, herons and egrets outside harvesting periods (i.e. drain-down), by increasing food resources and food availability and by reducing disturbance effects. Enhancement of the value of fish ponds to such birds outside harvest periods could reduce the potential for ‘feeding bottlenecks’ thereby possibly reducing the area of fish ponds needed to support the population.

• The management regime proposed is expected to benefit other species of conservation importance that currently use fish pond habitats. For example, the managed wetlands, at Mai Po which include areas of former fish ponds have been shown to support significantly higher densities of Greater Spotted and Imperial Eagles than occur in commercial fish ponds (refer to Baseline Report Appendix A4.2). Both are globally threatened. In addition, the provision of a less homogonous wetland area and the resultant increase in habitat diversity within the Lok Ma Chau fish ponds will provide habitat for other species that are generally rare within commercial fish ponds. The areas of reeds and marsh will be more suitable for small migrant passerines that the habitats available at present. For example, Pallas’s Grasshopper Warbler, a species that prefers dense rank vegetation and avoids open and sparse habitats would benefit. Micro-habitat details of the management proposals, and their suitability in terms of the habitat requirements for the Species of Conservation Importance are shown in Table 4.41.

• Increase their overall biodiversity value and suitability for other non-bird Species of Conservation Importance, such as some mammals, amphibians and reptiles, whilst maintaining their current important functions for herons, egrets and other water birds.

4.11.48 Figure 4.5 indicates the location of the proposed area of enhanced fish ponds. These would be placed away from the buildings to minimise disturbance impacts from the railway station and others sources such as the Lok Ma Chau border crossing. They would also be contiguous with the main area of fish ponds in the WCA and Ramsar site as a whole. Maintaining a contiguous area for compensation that is linked with an existing area of recognised conservation importance is of significant ecological value. As indicated in Appendix A4.1 these ponds are also regularly used by waterbirds at present.

Design Proposals for Enhanced Fish Pond Habitats at San Tin / Lok Ma Chau

Habitat Requirements of Target Bird Species

4.11.49 The key habitat requirements of target bird species of Conservation Importance that occur within the San Tin / Lok Ma Chau area are summarised in Table 4.41 below.

Table 4.41

Summary of habitat requirements for

target Bird Species of Conservation Importance at Lok Ma Chau

Key: habitat important for F = Foraging; R = Roosting; B = Breeding.

Species	Deep water	Shallow water	Muddy vegetation free margins	Reedbeds	Other emergent / marsh vegetation	Bare or sparsely vegetated bunds
Globally Threatened Species
Black-faced Spoonbill		F	F			R
Greater Spotted Eagle		F			F	F
Imperial Eagle		F			F	F
*Regionally Important Species*
Great Cormorant	F
Grey Heron		F			F
Great Egret		F			F,R
Little Egret		F			F
Chinese Pond Heron		F		F,R	F
Common Teal	F	F		F,R
Eurasian Coot	F	F
Black-winged Stilt		F	F
Red-billed Starling			F		F	F
Locally Important Species
Cinnamon Bittern		F			F,R
Pintail Snipe			F		F,R
Swinhoe's Snipe			F		F,R
Common Snipe			F		F,R
Richard's Pipit			F			F
Bluethroat			F	F,R	F,R
Common Stonechat				F,R	F,R	F
Zitting Cisticola				F,R	F,R

4.11.50 To provide these habitat requirements for target species and to meet the objectives for the enhancement of fish ponds it is proposed that main mitigation measures would be:

• Enlargement of small fish ponds to reduce enclosure effects (as small ponds are avoided by many birds)

• Re-profiling of fish pond bunds and the immediately adjacent areas to provide shallow sloping margins (and a variable bottom topography) that provide increased structural diversity. Shallow sloping margins will also increase feeding opportunities and the availability of fish and invertebrate prey to birds.

• Establishment of marginal emergent vegetation, including reedbeds and other species, to support and provide cover for invertebrates, amphibians, reptiles, passerine birds and mammals. Such vegetation may also provide screening of disturbance sources from feeding herons and egrets.

• Reductions in water depth during the winter, i.e. when deoxygenation problems are unlikely to occur, to increase the availability of fish and invertebrates to wading birds. This is considered to be a potentially very important enhancement. Observations of some fish ponds in the Deep Bay area by members of the study team have revealed that some abandoned shallow ponds are frequently used for feeding by various waders, herons and egrets, often including substantial numbers of the globally threatened Black-faced Spoonbill.

• Manipulation of the fish stocking, feeding / fertiliser regime and drain-down to optimise the food availability for birds.

Habitat Requirements for Other (Non-Avian) Target Species

4.11.51 The baseline survey confirmed that, as was indicated in the previous EIA Report, non-avian diversity in the Lok Ma Chau area is relatively low and most species present are relatively common and widespread. Though one rare and localised mammal species, the Eurasian Otter was observed, no plant, reptile, butterfly or dragonfly species of conservation importance were found during the baseline survey and only a single amphibian species of conservation importance, the Chinese Bullfrog, was recorded. However, reptile species of conservation importance noted in ERM (1999b) are relatively elusive and may still be present. Indeed, the occurrence of Chinese Soft-shelled Turtle (suspected to occur in ERM (1999b)) was first confirmed in the Study Area in November 2001. Accordingly, on a precautionary principle, targets for non-avian taxa are based on a combination of those species recorded in the baseline survey and those whose presence was noted or inferred in ERM (1999b) (Table 4.42), together with an overall target to increase wetland habitat and wetland species diversity in the area.

Table 4.42

Targets for non-avian species at Lok Ma Chau

*Group / Species*	*Habitat and Conservation Requirements*
Eurasian Otter	Open water with fish, dense emergent vegetation, overhanging banks/tree root cavities (for holts), disturbance free movement corridors
Burmese Python	Dense cover, mangroves, vertebrate prey
Chinese Soft-shelled Turtle	Ponds, soft mud, mud banks
Chinese Bullfrog	Ponds, emergent marsh vegetation

Construction and Management Works and Programme

4.11.52 Detailed design of the proposed Lok Ma Chau mitigation area including construction methods, management and monitoring is provided in the Draft Habitat Creation and Management Plan (Appendix A4.2) and is summarised below. The Habitat Creation and Management Plan will be finalised when an Environmental Permit is granted for the project incorporating modifications and improvements arising during the EIA process.

Enhanced Fish Pond Area

4.11.53 As the area already consists of fish ponds it is proposed that works be restricted to the modification of existing ponds, rather than construction of new ponds. These modifications will consist of the joining of selected ponds to reduce enclosure effects (see above). The proposed pond layout is shown in Figure 4.5.

Construction Works

4.11.54 Under normal operating conditions, fish ponds are profiled with steep sides to maximize the available capacity of the pond and deter large waterbirds from feeding at the edge. The operation is therefore aimed at maximizing the commercial value of the ponds for fish production.

4.11.55 Management of the fish ponds for wildlife incorporates similar principles of fish stocking and drain down as a commercial operation, but also includes modifications to the form of the ponds to maximize the feeding opportunities for waterbirds. Most of the large waterbirds (such as Great Egret and Black-faced Spoonbill) targeted in the provision of compensation habitats feed in the shallow margins or where bottom mud has been exposed, both in a marine and fish pond environment.

4.11.56 To improve the feeding opportunities within fish ponds at Lok Ma Chau and thus enhance the carrying capacity for large waterbirds, it is proposed to reprofile selected fish ponds to increase the shallow margin area. Due to the difficulty in stabilizing the soft bottom mud of the ponds, it is proposed to lower selected bunds as shown on Figure 4.6, to below the water line of the proposed operating water levels, and use the removed material to form a shallow slope to either side of the bund. This will increase the area of shallow water along the length of the bund. A longitudinal section of one of the reprofiled bunds is shown in Figure 4.7.

4.11.57 Reprofiling works will be carried out using small earth moving machines, similar to those used in normal fish pond operations. The number of bunds to be profiled and the volume of material to be moved is small. The works are therefore likely to have minimal impact and will take place over a short period.

Hydrology

4.11.58 Fish ponds are dependent on rainwater for filling and are effectively self-contained entities, which are not subjected to the dynamic water budgets of other open system wetland habitats. Water may be lost from the system due to evaporation, evapo-transpiration and filtration through the substrate. However, these losses are considered to be sufficiently low to maintain water levels in fish ponds within acceptable fluctuations, as such ponds are present in the area now and are currently being successfully farmed without water supply problems. Water recovered from ponds being routinely taken out of service on a three to five year cycle is recycled into the remaining ponds rather than being discharged from site. Details of water budgets and the proposed water management regime are provided in the HCMP (Appendix A4.2).

4.11.59 Accordingly, the traditional system of using rainfall to fill ponds and transferring water between ponds for drain-down or other management purposes is described in detail in the HCMP (Appendix A4.2). Where drain-down or other management requirements necessitate the transfer of large volumes of water, transfer between ponds will be by means of a permanently installed pipeline grid using mobile electric pumps and an engineered “hook-up” power supply system. Diesel-powered pumps will also be available as a stand-by system. Fine-tuning of water levels and the shedding of excess water from the system (for example following heavy rain) will be accomplished by means of manually-operated sluices.

4.11.60 Saline intrusions are also not considered to be a problem. As a component of environmental monitoring undertaken for the Fish Pond Study, the potential of saline intrusion was investigated due to ponds close proximity to the coastal area of Inner Deep Bay. However, no saline intrusion was found (Aspinwall, 1997).

Vegetation Establishment

4.11.61 In addition to the management of the fish farming system, some management of the bund vegetation would also be undertaken. Existing bund vegetation is not natural and is dominated by former crops and pantropical weeds. Much of this will have to be cleared initially mainly involving the control of tall vegetation and invasive weeds and replacement with more beneficial grass and herb species as is detailed in the HCMP. Ongoing management of the developing natural vegetation, especially stronger-growing species such as reeds will be required. Although some patches of reed would be encouraged to develop for cover and screening purposes these would need to be controlled. Ponds that are enclosed by tall vegetation tend to be avoided by many of the larger herons and egrets. Management would also be carried out of undesirable invasive weeds such as Mikania micrantha if necessary.

4.11.62 The effect of controlled vegetation management on the use of Lok Ma Chau area by large waterbirds was illustrated during November 2001 when bund repairs necessitated the cutting back of vegetation along most of the bunds in the proposed Lok Ma Chau fishponds compensation area. The removal of vegetation opened up viewing corridors previously hidden, and this change attracted large numbers of Black-faced Spoonbills to the site, despite the lack of suitable foraging conditions in the area. Other factors, such as the lack of disturbance, also attracted these sensitive waterbirds to the area, as described in subsequent sections.

Management

4.11.63 It is proposed that the main management enhancement of the ponds will be to regulate and extend the period of drain-down for harvesting. Under current fish-farming practices harvesting is carried out in winter by reducing the water depth of the pond (by pumping water to another pond for storage) and the gradual netting of the stock over a couple of weeks. This process is a very ad hoc one. Many ponds are drained only every three to five years, although some may be drained more frequently. At most, only one winter drain down takes place. The precise dates of harvesting are dependent on market prices and this can result in food-resource ‘bottle-necks’ if no or few ponds are drained at any one time. The first benefit of regulating drain-down periods in the mitigation area is that it can be timed to allow for staggered food availability, particularly at times when there may be low food availability in other areas of Deep Bay (based on current knowledge). Further, the option of re-stocking ponds with the sole aim of draining down to provide food resources for fish-eating birds, means that more than one drain-down per season can occur. By increasing food availability in such a manner, it is predicted that higher numbers of target species will occur within the study area.

4.11.64 A further advantage of the change from commercial fish ponds to wetland mitigation area is the associated lower levels of human activity on site. This is considered in part at least to contribute to the higher numbers of large waterbirds roosting within the resumption area during the 2000/2001 winter period. While a greater availability of food can also result in an increase in numbers, a reduction in disturbance levels can also have a positive impact. Preliminary surveys during November 2001 have shown that up to 141 Black-faced Spoonbills are using the ponds at Lok Ma Chau. These birds were roosting on one pond, and no other ponds nearby were in a condition suitable for foraging. It is considered that these birds were roosting in the area due to, in part at least, the low levels of human disturbance on the site. Thus in the past two winters, and in direct contrast to previous winters when the site was operated as commercial fish ponds, large concentrations of Black-faced Spoonbills have been present within the resumption area.

4.11.65 It is recognised that suitable management techniques can be beneficial to Black-faced Spoonbills. The conservation plan for this species in Hong Kong (WWF 2001) states that the following management measures for Black-faced Spoonbills have been implemented or are currently underway at Mai Po Nature Reserve (MPNR):

· managing water levels in order to provide areas for roosting and feeding;

· providing suitable areas of bunds with short grass (<30 mm) for roosting Black-faced Spoonbills;

· controlling vegetation (e.g. reed) encroachment into the areas that the Black-faced Spoonbills use;

· minimizing disturbance to the areas that the Black-faced Spoonbills use; and

· alternate draining of the gei wai on a 2-week cycle in winter to provide shallow water feeding habitats with a high density of prey for Black-faced Spoonbills.

4.11.66 The same report also states that no habitat management actions specifically for Black-faced Spoonbills are currently underway outside MPNR, and that the present situation with most Black-faced Spoonbills roosting within the MPNR is less than ideal

4.11.67 The current, on-going increase in Black-faced Spoonbill numbers in the Deep Bay area indicates that the carrying capacity of this species in Deep Bay has yet to be reached. Thus management actions that target this species away from MPNR have the potential to absorb part of this increase, and provide alternate roost sites.

4.11.68 During the baseline surveys of 2000/2001, the effect of draindown of fishponds on the functional value of the ponds to species such as Great Egret and Black-faced Spoonbill was evident as shown in the Baseline Report (Appendix A4.2). Immediately after each drain down event, Black-faced Spoonbills were observed feeding in the shallow margins of the pond. All large fish in these ponds had been harvested, leaving small “trash” fish and benthic invertebrates for the waterbirds to feed on. Prior to this, the fish pond management scheme had been drained down over a short period, every two or three years, principally for the purpose of harvesting large fish. The time for which the pond would remain drained was generally short, giving large waterbirds minimal feeding opportunity.

4.11.69 The proposed management regime for the enhanced fish ponds at Lok Ma Chau would provide a controlled draindown period, in a mosaic of ponds, rather than uncontrolled draindown of all ponds at once based on commercial interests.

4.11.70 Extension of the draindown period to a length of around 20 days is much longer than the normal commercial operation of 3 to 7 days and provides the second benefit of this management system. Extended feed times in selected ponds will further reduce potential feeding bottle-necks. Although food resources would be depleted with time it will maximise the benefit of trash fish food availability in each pond. The ponds would then be refilled in time for the normal fish stocking period. Detailed management of the drain-down regime will, however, be flexible. As is described in the HCMP, birds’ response to drain-down will be monitored and the response of the different target bird species will be taken into account in the fine-tuning of the management regime; for example in respect to fish stocking density, species and size, the rate of drain-down and the depth to which water is lowered.

4.11.71 It is also proposed that at any one time a couple of the larger ponds would be taken out of production (on a rotational basis) for two seasons. This would provide a number of more natural 'lake' like habitats thereby increasing habitat diversity within the area. Such habitats would be used by targets species such as herons and egrets, but would be particularly valuable habitats for ducks and non-bird taxa that are susceptible to the highly eutrophic conditions in managed fish ponds. Recent conversion of some fish ponds to similar freshwater habitats within the Mai Po Nature Reserve has produced highly valuable habitats that hold large numbers of wintering waterfowl.

4.11.72 As an example of this, reference is made to studies carried out in fish ponds close to Mai Po Marshes on the effect of draining down fish ponds on the abundance of piscivorous birds (Young, 1997). This study reports the importance of water level fluctuations in wetlands in determining wetland use by waterbirds. When the water level falls, aquatic prey become more concentrated and thus more available. The concentration, in turn, may attract more avian predators. To quote from the study:

“The winter draining of the Deep Bay fish ponds for harvesting mimics the drying out of natural wetlands. Because of the high density of non-commercial prey in these ponds, the effect is a sudden abundance of food for piscivorous birds. As a comparison, a drained pond supports an average of 231 Little Egrets and 34 Great Egrets, whereas a filled pond typically attracts less than five Little Egrets and one Great Egret.”

4.11.73 Additional examples of successful habitat enhancement using a variety of management techniques, including water level control, is given in Appendix A4.5.

4.11.74 The optimal management of fish ponds for biodiversity is the subject of field trials being carried out under the current AFCD Wetland Compensation Study. These trials include investigations of the biodiversity benefits and implications on fish farming of changing fish stocking levels, fertilizer and fish food inputs and the extension of winter draw-down periods for harvesting. The findings of these trials and their results will be taken into account in the finalisation of the long-term management regime for the enhanced fish ponds within the mitigation area. In addition, findings from the advance habitat management measures in the proposed initial (construction period) mitigation area will also be incorporated adaptively in the long-term management regime. The HCMP will thus be regularly reviewed and updated to reflect the findings and changes of the ecological compensation monitoring and management programme.

Monitoring Programme

4.11.75 An important aspect of this enhancement proposal is the mechanism for assessing the success of the management programme. The question of which criteria should be used to measure success has been the subject of intense debate in a number of proposed wetland enhancement projects in Hong Kong. The ultimate aim of the management programme is to provide suitable conditions to attract the target species to the area. The proposal to double the carrying capacity, as described above, effectively means that double the number of birds is expected, compared with baseline conditions. While a large number of birds of the target species may be a good indicator of success, their absence is not necessarily an indication of lack of success. Other factors often come into play. Another problem is the establishment of a reliable and realistic baseline. To obtain a baseline in which a high degree of confidence can be placed may require several years of study (as many of the species are migratory) and maintenance of similar conditions in surrounding habitats over this period. It can be seen in the Baseline Report (Appendix A4.1) and the records of observations in previous years, as presented in Appendix A4.3, that it is very difficult to establish a steady baseline for a given species. Many external factors affect the response of the bird populations to the regime established in a managed wetland. Where other ponds are being drained down closer to the roosting area of a group of birds, these ponds may be used in preference to fishponds at a more distant location. The lack of birds in the managed wetland at Lok Ma Chau may therefore simply reflect natural variation and behavior of the birds. While an indicative baseline can be derived from the bird data obtained during 1998-99 and 1999-00 winters, this data must be used with caution for reasons outlined above.

4.11.76 In addition to bird numbers, it is therefore proposed to monitor indicator parameters that show lower temporal and spatial variation, are easy to measure, and provide an indication of the suitability of the habitat to the species targeted. In the case of the proposed wetland compensation area at Lok Ma Chau, proposed indicators include both design and management criteria. As discussed in the draft HCMP (Appendix A4.2), one of the main design indicators is to increase the area of shallow water habitats compared with the present situation. The area provided through lowering of bunds and spreading the material into the adjacent fishponds to form shallow slopes, should at least double the area currently occupied by shallow slopes. Given the steep sided profile of commercial fishponds, this target should be readily achievable.

4.11.77 An increase in drain down frequency also increases shallow water areas and can be timed to provide a more regular supply of food instead of the all-or-nothing scenario under current fish farming practices. Other indicators or habitat optimisation are:

· Fish type and size for target avifauna;

· Water quality;

· Vegetation growth on bunds (this can be managed to match particular species requirements in different areas of the wetland);

· Soil and sediment characteristics;

· Composition of benthos in managed fishponds.

4.11.78 The rational of the proposed mitigation is to benefit the target bird species by changing the habitat type and food availability through changed management of the ponds, based on established knowledge of the requirements of target species. The target species would benefit from appropriate contouring of fishponds, draw down regimes designed to enhance food availability and physical measures to reduce disturbance. Hence indicators for evaluating the suitability of the mitigation area for the target species could include water quality, water level, availability of food source and establishment of plant species.

4.11.79 Given the temporal variation in bird numbers and the associated difficulty in establishing a baseline against which future bird numbers can be monitored, it is proposed to monitor both the number of birds using the managed wetland at Lok Ma Chau and at least three other areas of commercially operated fishponds at a given time. The management regime at these other sites would be recorded for comparison purposes. In addition to providing a quantitative comparison of bird numbers, this approach would also provide valuable additional information on the benefit or otherwise of a particular management regime.

Marshland and Reedbed Areas

4.11.80 The fish pond enhancement measures described above would be supported by the creation of some areas of reedbed and marshland habitat alongside the station buildings (Figure 4.7). Reedbeds will be established alongside the station complex to function as a barrier to disturbance and as shelter/cover for smaller herons, crakes, passerines, amphibians, reptiles and mammals. Additional marshland habitat would have a high carrying capacity for several such target Species of Conservation Importance as well as providing habitat for some that at present occur in the area only in small numbers (see Table 4.45).

4.11.81 An additional marshland area will be located at the southwest of the mitigation area. The target Species of Conservation Importance will be similar to the main marsh area but its location is such that it will be remote from any disturbance associated with the station. Because of this, and in view of its proximity to a river channel which forms a potential movement corridor through the fish ponds, this location has been identified as suitable for the creation of suitable refuge conditions for Eurasian Otters: overhanging banks with trees near the waterside would provide suitable sites for holts to be formed (by otters themselves). In addition artificial holt construction will be undertaken as a part of the mitigation measures.

4.11.82 An area of approximately 2 ha of reedbed will also be created alongside the station for water clean-up purposes (see Chapter 8). This habitat will provide additional habitat for reedbed species, potentially including smaller herons, bitterns, rails and various passerines.

Construction works

4.11.83 The reedbed and marsh area would consist principally of a shallow basin sloping gradually away from the station buildings, to produce a zoned wetland with drier terrestrial habitats on the upper slopes and permanently wet reed beds and pools at the lower end (Figure 4.8). Construction works outside the station boundary would, therefore, be minimal and would primarily consist of re-profiling of adjoining fish pond bunds and the land in between. The base material for raising the wetland to a level whereby the wetland contractor can create the wetland, will be done through the addition of pond bund material removed from pond bunds below the station platform. Superimposed on the slope would be a ridge and furrow profile perpendicular to the slope away from the station buildings. This would produce further structural diversity within the wetland leading to a scalloped edging to the vegetation zones. Some small depressions of 0.5 – 1.0 m greater depth than the adjoining substrate would also be made to provide additional permanent and temporary pools within the upper marsh / reedbed areas.

Hydrology

4.11.84 There is no watercourse with water that would be of a suitable quality for the maintenance of reedbed and marshland habitats for biodiversity purposes. Also ground water within the area is likely to be saline. Therefore it is envisaged that the reedbed / marshland habitats would need to be primarily maintained by rainfall. However, a water budget for the area suggests that direct rainfall would be insufficient to maintain areas of permanent wetland across most of the mitigation area (see Draft HCMP (Appendix A4.2)). It is therefore proposed that additional rainfall would be obtained from intercepting some of the runoff from the station roofing area. This would provide sufficient additional water to maintain a reedbed and marshland with standing water with an average depth of 0.5 m when full (as controlled by a drop-gate weir) during the wet season. In addition, the reedbed area to the east of the station will be fed by the flow of treated sewage effluent from the sewage treatment plant in the Lok Ma Chau Station. It is not proposed to pass any of this effluent through the main marsh area, to avoid build up of pollutants in the marsh.

4.11.85 Additional water from the station complex would be fed through culverts in the station boundary bund and then a proportion would enter the furrowed and sloping reedbed marshland site. Water would then flow with gravity and collect at the slope bottom alongside the perimeter bund. As the soils are considered to have very low hydraulic conductivities, as indicated by the presence of fish ponds within the area, it is anticipated that water losses to the ground will be minimal. Water levels within the marsh will be controlled by drop-gate weirs with excess water draining into the water course to the west of the station (Figure 4.7). This hydrological regime will produce a relatively diverse wetland with a hydrological gradient leading to a wetland zonation from dry non-wetland habitats adjoining the station to permanent wetland with standing water at the slope bottom.

Vegetation Establishment

4.11.86 Details of proposed wetland plant communities (including planting lists, densities and matrices) in the marsh are provided in the Draft HCMP (Appendix A4.2) and are illustrated in Figure 4.8. Upper areas of the marsh will grade from wetland plant communities that rely on seasonal inundation, to those which only withstand high water tables, to non-wetland species. Some areas will be maintained as lightly vegetated or bare soil zones to provide roosting, loafing and nesting habitats for species that prefer open areas.

Management

4.11.87 One of the aims of the design of the wetland area will be to reduce management interventions to a minimum, through the creation of a natural sustainable wetland system. No water pumping or day-to-day water control will be necessary, with water regimes largely following seasonal cycles.

4.11.88 However, some management will be needed to avoid excessive vegetation growth as some open areas of habitat are important for many target Species of Conservation Importance (see Table 4.41). Also, with time, management will be needed to arrest succession processes and the loss of wetland habitats to terrestrial ecosystems. Ideally much vegetation control and the maintenance of valuable areas of open mud and water can be carried out by the use of carefully managed grazing animals, such as water buffalo or domestic cattle. If this is not possible, selective cutting and removal will control vegetation. Proposed management and monitoring regime is described in more detail in the Draft HCMP.

4.11.89 Reedbeds will be cut in compartments on a rotational basis, at varying frequencies (to increase habitat diversity), to maintain condition and vigour of the vegetation. Occasional mechanical removal of rhizomatous material will control reed encroachment on areas of open water. Such manual weeding is generally preferable to spraying of chemicals.

4.12 Proposed Programme for Wetland Creation to Minimize Residual Impacts

4.12.1 The previous section has illustrated how the principle of enhancement can be effectively used to increase the ecological value of the fishponds in the compensation area. These techniques will be employed at an early stage to maintain a positive balance of functional habitat as far as possible during the construction phase.

4.12.2 The western part of the fish pond mitigation area is located from 200 m to more than 500 m from the station works area i.e. beyond the area of disturbance for the large waterbird species, including Ardeids and Black-faced Spoonbills, which are key Species of Conservation Importance for the mitigation area. The management regime described above for this area will be established in advance of any construction at Lok Ma Chau station site.

4.12.3 It is proposed that KCRC will let a contract in Spring 2002 for wetland creation and fisheries management, to carry out the necessary enhancement measures on an area of around 15 ha of ponds in the western zone of the compensation area (beyond the 200m zone) as is shown in Figure 4.10a. As described above, pond bunds will be reprofiled, some ponds will be stocked with fish, others (probably those furthest from the future station site) will be used as frequent draindown ponds where disturbance sensitive large waterbirds will feed.

4.12.4 When the station and viaduct construction starts, the direct loss of 7.0 ha fishponds beneath the station platform, will be compensated for by the early enhancement of these fishponds in the western section of the compensation area. Disturbance from the station construction has been taken into account in the compensation habitat requirement during construction, including direct habitat loss and disturbance (Table 4.39). During the construction phase, several measures will be put in place to minimize overall loss of functional habitat before the full compensation area is implemented. These measures include:

(a) Early filling of the fishponds to create marsh to the south of the station to allow grading, profiling and planting in areas not affected by the station works. This will provide a buffer area to the surrounding fishponds and will provide habitats to other less disturbance sensitive species.

(b) Use of other fishponds close to the station as fish stocking ponds and a water resource especially in the dry season. Although one of the ponds directly to the west of the station is within 100 m exclusion zone from the station site, it can still have a functional value as part of the overall compensation area.

(c) Ponds between 100 m and 200 m zone from the station boundary may be subject to disturbance, resulting in a reduced density of large waterbirds, particularly during construction. Landscaping along the west and south of the station area should be undertaken as early as possible to minimize the potential disturbance in this zone.

4.12.5 Figures 4.10a, 4.10b, 4.10c show the progression of implementation of wetland areas during station construction and the final layout of the wetland compensation area, including lines of potential disturbance. As stated above, after completion of station construction, the 100 m and 200 m zones of disturbance are measured from the station building and not the edge of the drainage channel, which should be designed to blend with the current fishpond habitats and not create disturbance per se.

4.12.6 Table 4.43 shows a balance sheet of functional value of habitat before construction and the functional value of that to be replaced after completion of Spur Line.

Table 4.43

Comparison of Functional Values of habitats before and after

Construction of Lok Ma Chau Spur Line

Undisturbed area (ha)

Functional value

Disturbed area (ha)

Functional value

Additional habitat area (marsh, reedbed)

Equivalent functional value of area

Before construction

44.0*

4.4**

Various**

46.6

After construction

22.3

4.7 (station)

4.4 (viaduct)**

2x50%=1

Various**

(9.9)

50.0***

* Includes the total area of fishponds impacted through the project: 7-0 ha station footprint, 27.1 + 5.0 + 4.9 ha (future compensation area).

** The fishponds under the viaduct close to Lok Ma Chau Boundary Crossing have a physical area of 4.4 ha. However, due to disturbance from LMC Boundary Crossing, the functional value is reduced to 2.6 ha. These fishponds will be reinstated after construction. Disturbance due to both Lok Ma Chau Boundary Crossing and Spur Line viaduct reduces the functional value to 0.7 ha. The disturbance ratio varies because of the complexity in overlapping with Lok Ma Chau Boundary Crossing.

*** Total area enhanced does not include 9.9 ha marsh/reedbed.

Note: Doubling of the functional value of the managed compensation area is considered to be highly conservative for reasons outlined in this assessment.

4.12.7 Table 4.43 shows that there is an increase in functional value of the overall area after compensation is complete. This assumes a doubling of the carrying capacity of the ponds which is considered to be highly conservative. Early enhancement of approximately 15ha of fishponds to the west of the proposed Lok Ma Chau station site formation will be implemented before construction starts (see Figure 4.10c). This will enable pond stocking, water level management and ecological monitoring to be implemented and optimised before major construction works begin. It was stated earlier that a doubling of the carrying capacity was expected to be readily achievable through the management techniques proposed. Data obtained during 1998/99 and 1999/2000 winters (Appendix A4.3) and during the Baseline Study 2000/2001 (Appendix 4.1) indicates that using the management techniques proposed, such as regular and prolonged draindown events, this doubling of value can be readily achieved. With the implementation of additional measures such as bunds to provide shallow margins and appropriate fish stocking, the value of double is considered to be highly conservative.

Construction Stage Compensation

4.12.8 During construction the pond filling process is likely to be in stages and to take place over a period of about 6 months in total. The most disturbing activity is likely to be piling for the station foundations. Hoarding will be required to protect the wetland enhancement area from excessive noise and visual impact. However, disturbance is still expected up to about 200 m from the station footprint, particularly for large waterbirds, as described in Table 4.28. Enhancement of fishponds within the compensation area during the construction period will include undisturbed ponds beyond 200 m and ponds between 100 and 200 m for which a reduced density of use is assumed (Figure 4.10b). As is discussed further below, the capacity of the undisturbed ponds within the compensation area can be much more than doubled in terms of their functional value for the target species of large waterbirds by means of active management measures.

4.12.9 The most disturbing activities during construction are likely to be related to the piling activities required for the station terminus. This section of the works will last for approximately 9 months according to the latest programme. Other activities during the construction period are expected to cause less disturbance. In addition, the degree of enhancement that can be achieved is a highly conservative estimate. In particular, it is clear from stocking trials conducted in the proposed early enhancement ponds during November and December 2001 that repeated restocking with trash fish at frequent intervals will attract large numbers (often several hundred) of the target species (Black-faced Spoonbills, Great Cormorants and large ardeids). Such repeated restocking clearly requires an intensive management regime and the concentrations of the larger target species which can be created by such measures would not be necessary to meet the target doubling of carrying capacity over the mitigation area as a whole in the long term. However, the combination of the long-term / permanent measures described in paragraphs 4.12.2.- 4.12.4 (above) and these intensive stocking measures will ensure that the carrying capacity of the early enhancement area can be maintained at a level to match the carrying capacity of the construction area and the disturbed area throughout the construction period, hence satisfying mitigation target requirements.

4.12.10 Thus, it is considered that with suitable management and monitoring in place, the functional value of the compensation area will at least match that of the area calculated to be impacted throughout the construction period. However, in the event that for short periods the number of birds utilising the early enhancement area fell below target levels any impacts would be minor and temporary. The fish pond area of Lok Ma Chau occupied by the station and its maximum disturbance footprint of 23.6 ha (Table 4.39), forms only 2% of the Deep Bay fish pond area. The large waterbirds which would potentially be disturbed are highly mobile (Carey et al. 2001) and would, therefore, be able to respond to disturbance by temporarily moving to other areas.

Operation Stage Balance Sheet

4.12.11 During operation (Figure 4.10c), the compensation area will be increased and the overall functional value will rise to 50.0 ha fishponds (equivalent functional value) and 9.9 ha reedbed/marsh (Table 4.43). The mitigation package proposed is therefore more than adequate to compensate for direct and indirect impacts to the ecological functions of the Lok Ma Chau fishponds area.

4.12.12 The creation of a reedbed and marsh within the overall compensation area adds value to the habitat diversity of the area. The apparent “loss” of fishponds to create these habitats has already been taken into account in the calculation of habitat required, as these areas are largely within the disturbance zones of the station boundary.

4.12.13 Elsewhere, at Chau Tau and to the east of the Boundary Crossing Plaza, habitats which will be temporarily impacted whilst construction is underway will be re-instated once railway construction has been completed (see Table 4.46 and the Chapter on Landscape and Visual Impact.

Overall Residual Impacts from Habitat Loss and Disturbance at Lok Ma Chau During Construction

4.12.14 It is considered that by a combination of fish pond enhancement and the creation of a more intensively managed reedbed and marshland area it is realistic to predict that at least a doubling in the carrying capacity of the current fish pond habitat can be achieved overall, thus eliminating residual impacts to Species of Conservation Importance from habitat loss and disturbance.

4.12.15 The proposed areas and land uses of this proposed provision are shown in Table 4.44. This indicates that over most of the habitat compensation area it is intended that habitat management of the enhanced fishpond area will involve the active continuation of fish farming, albeit with the objective of supporting wildlife rather than commercial fish production as was formerly the case.

Table 4.44

Land requirement for compensatory habitat provision

and other creation of habitats of ecological value

Land use	Land area (ha)	Notes
Enhanced fish ponds	27.1	Subject to management regime discussed above
Marshland	4.9	Wetland area around station
Reedbed/Marsh	5.0	Reedbed required for wastewater polishing. The remainder of the 5 ha will be used as additional marsh habitat for habitat diversity.
Bamboo / tree / shrub / reedbed / planting	1.0	Required for screening of station complex

4.12.16 The area of compensatory habitat provision of approximately 27.1 ha (overall functional value with reinstated fishponds to east of LMC Boundary Crossing of 50.0ha) and 9.9 ha of reedbed/marsh allows the creation of a coherent management unit of ponds to the west of the station site and ensures that the compensation area comprises entire ponds.

4.12.17 The reedbed area around the station will be used for screening and part of the area will be used for polishing of wastewater from the Lok Ma Chau station. In this context, it is recommended that the reedbed be established during the construction of the sewage treatment plant so that it is established before commissioning of the sewage treatment system.

4.12.18 The overall levels of compensation predicted from the above proposed compensation measures for Species of Conservation Importance that were recorded during the Baseline Surveys in the Lok Ma Chau fishpond area are summarised in Table 4.45.

Table 4.45

The overall levels of compensation predicted from compensation measures for Species of Conservation Importance that were recorded during the baseline surveys in the Lok Ma Chau fishpond area

Species	Sensitivity to disturbance	Compensation achieved
Mammals
Eurasian Otter	High	Refuge area fully compensated; overall increase in optimum habitats
Birds
Globally Threatened Species
Black-faced Spoonbill	High	Feeding habitat fully compensated and provided over a longer period; additional secure roosting habitat provided
Greater Spotted Eagle	Very High	Additional feeding habitat provided*
Imperial Eagle	Very High	Additional feeding habitat provided*
Regionally Important Species
Great Cormorant	High	Feeding habitat fully compensated; additional loafing habitat provided
Grey Heron	High	Feeding habitat fully compensated and provided over a longer period; additional loafing habitat provided
Great Egret	High	Feeding habitat fully compensated and provided over a longer period; additional loafing habitat provided
Little Egret	Intermediate-High	Feeding habitat fully compensated and provided over a longer period; additional loafing habitat provided; potential roosting and nesting habitat provided
Chinese Pond Heron	Intermediate	Feeding habitat fully compensated and provided over a longer period; additional loafing habitat provided; potential roosting and nesting habitat provided
Common Teal	Intermediate-High	Fully compensated and more optimum habitat provided
Black-winged Stilt	Intermediate-High	Fully compensated
Red-billed Starling	Low-Intermediate	Fully compensated
Declining in Hong Kong
Black-naped Oriole	Intermediate	Fully compensated: favoured habitat (wet woodland fringe) to be provided]
Locally Important Species
Common Snipe	Intermediate	Fully compensated: favoured habitat (marsh) to be provided
Pintail Snipe	Intermediate	Fully compensated: favoured habitat (marsh) to be provided
Swinhoe's Snipe	Intermediate	Fully compensated: favoured habitat (marsh) to be provided
Richard's Pipit	Low	Fully compensated
Common Stonechat	Low	Fully compensated
Zitting Cisticola	Low	Fully compensated
Amphibians	Nil	Existing habitats enhanced; more favoured habitat for many species (marsh) to be provided
Reptiles	Low	Existing habitats enhanced; more favoured habitat for many species (marsh) to be provided

* The Baseline Survey showed that these species only occur in the area occasionally. However, the attraction of other waterbirds (notably ducks) will increase feeding opportunities for these species.

4.13 Other Mitigation measures during the Construction Phase

Minimisation of Dust Deposition

4.13.1 Dust deposition is a potential adverse impact in all locations except the tunnel section, including storage yards. Dust creation should be minimised using standard procedures, including the damping down through water spraying during periods of dry weather. Details of mitigation measures to be used for minimising dust deposition are included in the Air Quality Impact Assessment.

Minimisation of Increased Sediment Load

4.13.2 The potentially increased sediment load during construction will be controlled and minimised through implementation of good site management practices such as the provision of means for the sediment to settle before discharge of the clear supernatant. During operation, sediment load is likely to be minimal and any solids will settle in the oil interceptors and sediment traps that are incorporated in the drainage system. With good management and maintenance programmes, these measures should minimise potential impacts from this source.

Minimisation of Pollution from the Railway Operations (e.g. Oil leaks) or Accidents Involving Toxic Chemicals

4.13.3 Good storage practices and handling of the chemicals used during the construction period will minimise the opportunity for impact on the terrestrial and aquatic environments. Spillage impacts can be minimised by storing chemicals in bunkers that contain the volume of the containers stored. During operation, on above-ground sections of the line there is a potential for oil and grease to be washed off parts of the train during – wet weather. This will be minimised through train design reducing exposed parts to wet weather, and provision of an oil interceptor within the drainage system. Oil and grease from the track maintenance operations is expected to be minimal along the majority of the alignment, but at locations where turnouts and crossings are located, oil and grease are used to maintain smooth running of trains. At these locations, oil interceptors are required to remove oil and grease before the discharge enters local watercourses. In the Lok Ma Chau area, discharge may be into fishponds (in compliance with the Zero Discharge Policy) and the water quality standard required is likely to be higher. Regular maintenance of the interceptor will maximise its efficiency in trapping oil before release into the environment.

Soil Compaction

4.13.4 Where works is being carried out, there is potential for compaction of the ground surface. The extent of the area to be compacted for works during construction should be minimised to reduce damage to habitats. Unless immediately required as a part of the managed mitigation area or for landscape impact mitigation purposes, each area should be re-instated when the works on that area is complete, to re-establish an environment as similar as possible to the original habitat. This may require excavation, removal of compacted (and polluted) material, and replacement with suitable material for re-creation, particularly in the areas of wetland creation and directly alongside the track where wetland is impacted.

Minimisation of Hydrological Disruption on above Ground Sections of the Line

4.13.5 During construction, a temporary drainage system must incorporate necessary sedimentation areas to minimise sediment lost in surface run-off. This applies wherever works are carried out above ground and particularly close to watercourses, such as next to the Rivers Sutlej and Beas, at Chau Tau and in Lok Ma Chau area. In the operational period, the drainage system will be designed to direct rainwater from the box girder section of the rail track, into a catchpit at ground level. Where oil and grease are used on the track, the run-off should pass through an oil interceptor before discharge.

4.14 Mitigation Measures during Operation

Habitat Loss and Disturbance

4.14.1 No additional habitat loss will occur during the operation period of the railway. All direct habitat loss occurs during construction and is compensated through the proposed enhancement measures described above. Impacts due to disturbance during construction are taken into account in the calculation of overall compensation requirements. During operation, disturbance impacts are likely to occur from the physical presence of the station building, and will not extend to the edge of the site formation as occurs during construction.

4.14.2 The disturbance effect from the station building will be mitigated through creation of a marsh around the station boundary and screening of the building through planting of bamboo and mixed trees and shrubs (Figure 4.10c). The channel along the western fringe of the station boundary should be designed to blend in with the surrounding fishpond and marsh habitats, utilising grasscrete within the channel and vegetated bunds as far as possible. In this way, the channel will provide a beneficial function to wildlife using the ecological mitigation area rather than creating a disturbance impact.

4.14.3 The noise reduction system that will be used on the Spur Line comprises an advanced multi-plenum structure that will absorb noise generated from the train and the track. A sophisticated viaduct and tunnel design provides additional mitigation in the reduction of noise from vibration. These measures are described in the Noise Chapter.

Direct Mortality related to Structures

4.14.4 The risk of birds colliding with power lines along the viaduct section can be reduced by increasing the visibility of the lines. Accordingly, measures should be taken to ensure that all power lines are highly visible and monitoring during the operational period should cover searching for any possible mortality.

Minimisation of Hydrological Disruption Underground Sections of the Line

4.14.5 The physical presence of the tunnel during the operation phase has the potential to impact groundwater levels by holding back groundwater upstream of the tunnel. The impact assessment, carried out using groundwater-modelling techniques, shows that the presence of the tunnel below the aquifer avoids impacts to the groundwater levels. A differential of 10mm from the norm of the upstream and downstream groundwater levels may occur,which is minor in comparison with the tidal influence on the current groundwater levels. Full details of the impact assessment are provided in Chapter 3. 4.15 Implementation of Mitigation Measures.

4.15 Implementation of Mitigation Measures

4.15.1 The direct ecological mitigation areas proposed for the Spur Line totals approximately 27.1 ha of fishpond habitat and 4.9 ha of marsh at Lok Ma Chau. In addition, 1.0 ha of bamboo planting provided as landscape screening around the station and approximately 2.0 ha of reedbed planting created for effluent polishing will be formed as managed wildlife habitats. An additional 3.0 ha is provided alongside the reedbed side for additional marsh habitat. The construction, management and monitoring of these areas will be undertaken by KCRC.

4.15.2 In the previous EIA Report it was stated that future management of the ecological mitigation areas might be carried out through the establishment of a HKSAR wetland management organization. For the avoidance of any doubt, and in direct fulfillment of the requirements of paragraph 3.5.2 (x) of the Study Brief, it is confirmed that KCRC does not now intend to pursue this proposal. Thus, KCRC will, itself, remain responsible for management in perpetuity unless an alternative management authority is agreed with Government and is permitted under the terms of an Environmental Permit.

Implementation of Mitigation Measures and Fulfillment of the Terms of an Environmental Permit

4.15.3 The management of the mitigation areas will be undertaken by a dedicated management team established by KCRC which will be responsible for this and other managed wetlands and wildlife habitats (notably the Kam Tin Wetland Mitigation Area) for which KCRC is responsible. In addition, it will report to a Management Committee, established by KCRC. This Committee will produce an Annual Report that would be made available to interested parties including Government, Green Groups and local villagers.

4.15.4 KCRC proposes that the programme for the construction of the Lok Ma Chau mitigation areas should commence immediately on approval of the EIA and the grant of an Environmental Permit. This is tentatively programmed for April 2002. Initial enhancement work will focus on the western part of the mitigation area (the area most remote from the proposed station site). The initial enhancement work is programmed to take a total of 6 months and hence will be in place by October 2002. This is the commencement of the dry season and the period when the ponds will host numbers of migrant waterbirds. The initial enhancement area will occupy approximately 15 ha (Figure 4.10c); corresponding to the footprint of the station site. The formation of the enhanced wetland will then progressively be extended eastwards. Completion of the full mitigation area must interface with completion of the station and viaduct, around 2006. However, enhancement management measures will be undertaken at the earliest opportunity, subject to the requirement to avoid unnecessary abortive work, and measures in most of the proposed mitigation area will not be contingent on the station construction timetable.

4.15.5 In this respect, it should be noted that all the land around the future station (including that required for the mitigation area) is vacant Government land. Accordingly, no delay in securing the land required for ecological mitigation is anticipated.

4.15.6 As an added benefit to the development of the ecological compensation area, consideration should be given to the development of a viewing area within Lok Ma Chau station and incorporation of environmental education features to the design of the station.

4.15.7 Details of the wetland construction and management measures, together with the programme for their implementation, are provided in the Draft HCMP (Appendix A4.2). These include, inter alia, the following key Standard Operating Procedures for pond management:

· the physical structure of the fish ponds (including bund and bottom profiles);

· timing of draw-down periods for harvest;

· frequency of complete drainage and re-working of ponds;

· frequency of set-aside from operations (i.e. no stocking) for selected ponds;

· fish stock composition and densities;

· the use of fertilisers and food;

· location of buildings;

· use of pesticides and aquaculture chemicals, and

· management of bund vegetation.

4.15.8 KCRC will be responsible for monitoring and reviewing the ecological effectiveness of the compensation measures. The monitoring and review process is an integral part of the Habitat Creation and Management Plan (see Appendix A4.2) and will include the following specific requirements:

· Annual preparation of a Monitoring Report detailing key physical and biological information collected during the monitoring programme during the previous year. These will cover the achievement of targets, any targets not met and action and limit threshholds exceeded, together with measures taken to resolve exceedences. Where necessary, this will include the requirement for adaptive modifications to the HCMP.

· A Five-yearly review programme for the HCMP, which will include both qualitative and quantitative review of management objectives and targets, together with measures necessary to accomplish any revised objectives, and targets that are set.

· It is anticipated that the Monitoring Report will be a public document available to concerned parties, whilst the Five-yearly review will be prepared in consultation with stakeholders including, but not limited to Government Departments, ACE and Green Groups.

4.16 Estimate of Residual Impacts

4.16.1 An estimate of residual impacts taking into account the feasible and proposed avoidance, minimisation, and compensation mitigation measures described above are presented in Table 4.46.

Project	Period of Works
Lok Ma Chau Boundary Crossing	May 1999 - 2003
San Tin Eastern Main Drainage Channel	September 2002 – 2005
Fanling and Sheung Shui Main Drainage Channels (Long Valley area)	June 1999 - 2003 (some elements delayed)

Location	Area (ha)	Habitat type	Habitat evaluation
Lok Ma Chau	9.1	Inactive fish pond	Moderate – High
Under viaduct east of Lok Ma Chau Boundary Crossing	0.4	Active fish pond	Moderate – High
Chau Tau	0.1	Inactive fish pond	Low – Moderate

Location	Area (ha)	Habitat type	Habitat evaluation
Lok Ma Chau	9.1	Inactive fish pond	Moderate - High
Under viaduct east of Lok Ma Chau Boundary Crossing	0.4	Active fish pond	Moderate – High
Chau Tau	0.1	Inactive fish pond	Low – Moderate

Potential impact	Potential mitigation measures				Predicted residual impact
	Avoidance	Minimizing	Compensation
	Avoidance	Minimizing	On-site	Off-site
Habitat loss	Much of the line has been placed underground, hence avoiding all ecological impacts in Long Valley and Chau Tau. At Lok Ma Chau, slight realignment of the track to minimise habitat loss and for compatible engineering reasons has already been carried out and taken into account. Further re-routing is not feasible	On the overground section of the route, all habitats of conservation importance that are occupied or ecologically altered should be restored Contractor access will be minimized in ecologically sensitive areas, such as WCA, through contract requirements and implementation on site.	Temporarily lost fishponds, agricultural and marshland habitats to be reinstated between Chau Tau and Lok Ma Chau. . A compensation area will be provided around the Lok Ma Chau Station. Early commencement of enhancement works on mitigation areas in Lok Ma Chau to minimise construction impacts.	Not applicable.	Provision of compensation areas will result in minimal impacts to Important Habitats (fish ponds) and associated wetland Species of Conservation Importance during construction. Advance construction of managed ponds will be undertaken to minimise impacts. No residual impacts on Species of Conservation Importance once proposed fish pond compensation area at Lok Ma Chau is implemented. No significant residual impacts from direct habitat loss on other habitats
Direct mortality	Line is placed underground for much of its length including the Chau Tau area where owls and raptors might otherwise have been encouraged to forage along the line. Avoid use of transparent and reflective materials on station and other structures	Mark aerial cables where feasible.	Not applicable	Not applicable	Very low residual impacts are unavoidable
Habitat fragmentation	Line placed underground in Long Valley and Chau Tau, hence fragmentation eliminated.	On overground section, elevated tracks and restoration of suitable habitats under the viaduct will allow passage of Species of Conservation Importance.	At Lok Ma Chau the mitigation area will be linked to the larger wetland area of Inner Deep Bay. Micro-habitat design will enhance links to surrounding ponds and channels.	Not applicable	Compensation of habitat as described by advance creation of managed wetland at Lok Ma Chau will minimise impacts to Important Habitats and associated wetland Species of Conservation Importance during construction. Low impacts are likely during the operation phase.
Disturbance of wildlife by noise and visual movement	Line placed underground at Long Valley and Chau Tau hence disturbance eliminated in this section.	Artificial screening and natural buffers (e.g. trees) should be used to reduce noise and the visibility of people in sensitive areas (e.g. close to wetlands)	A compensation area will be provided around the Lok Ma Chau Station to mitigate disturbance impacts. Early construction of this area is necessary in order to avoid serious impacts.	Necessary to avoid serious impacts to disturbance sensitive bat Species of Conservation Importance at Chau by enforcing restriction of Works Area boundaries and provision of temporary screening. Necessary to minimise noise impacts on Long Valley by controlling and screening noise sources from construction activities to the east and west of the Valley. .	Provision of compensation areas will minimise impacts to wetland Species of Conservation Importance during construction. Operational impacts will be negligible as disturbance from railway at Lok Ma Chau is insignificant compared with road Boundary Crossing.
Dust deposition on surrounding habitats	Line placed underground in Long Valley and Chau Tau, hence no dust deposition in this section.	In viaduct section and station site standard construction mitigation measures should be used (e.g. watering of dry surfaces to reduce dust)	Not applicable	Not applicable	Overall ecological impacts are likely to be minimal.
Increased sediment load and pollution of watercourses	In the operation of the railway, particularly in relation to the use of chemicals and oil and grease application to tracks, all feasible steps should be taken to avoid accidents.	A suitable drainage system should be established, including sedimentation and infiltration areas in necessary positions to intercept construction site runoff. Contingency measures should be planned for rail operations, in the anticipation of accidents which may lead to potential water pollution impacts	Not applicable	Not applicable	Minimal residual impacts.
Soil compaction	Risk of soil compaction avoided in Long Valley by placing line in a tunnel.	Minimise areas of soil compaction at Lok Ma Chau.	Habitat creation at Lok Ma Chau will include measures to minimize adverse impacts.	Not applicable	Minimal residual impacts.
Hydrological disruption	Use of Earth Pressure Balance Tunnel Boring Machine to prevent water ingress during tunnelling operation. Tunnel will be located below main aquifer and thus have minimal effect on groundwater levels.	Suitable drainage design to spread run-off as much as possible and avoid disruption to rainwater and fishpond management regime in the Lok Ma Cha and San Tin areas.	Water management regime will be incorporated into the habitat management plan for compensation areas.	Water management regime will be incorporated into the habitat management plan for compensation areas.	No residual impacts.

REFERENCES