Table 11.5 Implementation Schedule for Ecological Requirements

EIA Ref^#	Environmental Protection Measures / Mitigation Measures	Location / Timing	Implementation Agent	Implementation Stages*				Relevant Legislation and Guidelines
				Des	C	O	Dec
S7.7.1- S7.7.7. S7.8.2, S7.8.4 S7.8.15- S7.8.18	Design of River Channels The scale of impacts to river habitats would be determined largely by the design of drainage channels built to replace existing rivers. Ecological requirements have been considered during the design of drainage improvement works, and are described as follows. Pak Ngan Heung River Drainage improvements would be implemented by constructing an underground channel that would bypass a sharp bend in the river close to Butterfly Hill. Under normal conditions, flow would be maintained within the existing river channel. During high flow events, excess floodwaters would be conveyed through the by-pass channel, Under this design, modification to the existing PNH River would be limited to two short sections upstream and downstream of the proposed Bypass Channel. At the downstream section, the river channel would be slightly widened, with new vertical concrete retaining walls constructed along the banks of the channel. The channel widening would result in some new sections of riverbed being created, which would be lined with natural materials such as small cobbles and boulders. The existing riverbed and substrates would be retained. The upstream section of PNH River would be widened and slightly re-aligned. The new channel banks would be trapezoidal in cross-section, and lined with rock-filled gabion. Pits would be provided in the gabion bank to allow for planting and establishment of riparian vegetation. The depth of the new channel bed would be varied to re-create the pool-riffle sequence found in the existing River, and a small weir at the upstream end of the existing river currently maintained for crop irrigation would be re-instated. Similar to the downstream section, the newly constructed riverbed would be lined with natural materials such as cobbles and boulders. Tai Tei Tong River Proposed drainage improvements at TTT River would be limited to the widening of three small bottlenecks along the existing river. The bottleneck at the downstream end of TTT River (close to the confluence of the three rivers) would be widened along one bank only, with a new concrete retaining wall constructed along this bank. At the two upstream bottlenecks, the newly widened banks would be stabilised with rock-filled gabion. Luk Tei Tong River Lower section of the LTT River would be slightly widened and deepened (total length 225m). Ecological enhancement features to be included along the improved river section would include: · The channel bed would be constructed using natural materials such as small cobbles and boulders. · The depth of the channel would be varied to re-create the pool-riffle sequence found in the existing river. · The new channel banks would be trapezoidal in cross-section, and lined with rock-filled gabion. Pits would be provided in the gabion bank to allow for planting and establishment of riparian vegetation. Luk Tei Tong (2) River The proposed works would largely avoid direct impacts to the river by creating a flood Bypass Channel, with just small sections of the existing river connecting to the upstream and downstream ends of the Bypass Channel affected. Similar to the PNH River, existing flow within the flow LTT (2) River would be maintained under normal conditions, with excess flow diverted to the Bypass Channel during high flow events. Unlike the PNH River Bypass Channel, the LTT Bypass Channel would be open, not routed underground. General As the new drainage channels would be approximately the same width as the existing watercourses, it is anticipate that most of the substrates used to line the new channel beds can be taken from the existing rivers. Rocks unearthed during excavation works for this Project or material purchased from local quarries would be used as material to fill gabion bank linings and as additional substrate to line the riverbeds if required. In time, it is expected that vegetation will naturally re-colonise newly constructed channel sections. To expedite this process, planting of suitable aquatic, emergent and riparian plant species within the beds and gabion-lined sections of channels will be undertaken following the completion of works (Table 2.7 lists some suggested species for use in this planting). Additionally, the gabion lining will be hydroseeded. Planting design will be finalised in the detailed design stage. The newly created PNH River drainage channel is expected to provide a suitable habitat for the fish species of conservation interest (Flagtail, Kuhlia marginata) previously recorded from the river. To further increase the value of the PNH River for this and other fish species, it is recommended that a small fish ladder is constructed at the upstream end of the new channel. The existing agricultural weir at this location currently impedes the movement of fish between upstream and downstream sections of the river. The fish ladder would facilitate movement past this obstacle, extending the range of fish communities in both upstream and downstream areas. A conceptual layout of the proposed fish ladder is given in Figure 7.3, showing a basic design of rock-ramp fishway commonly adopted in Australia and other countries to facilitate the passage of various fish species over low obstructions. The detailed design of the ladder would be finalised at a later stage of this Project.	River channels during design/construction phase.	Project Proponent/ Contractor.	Ö	Ö			-
S7.8.3.	Avoidance of Disturbance to Breeding Fauna The works programme has been considered to avoid impacts to breeding wildlife where possible. Works within Luk Tei Tong Marsh and the confluence of the three rivers would be restricted to the dry season, thereby avoiding impacts to White-shouldered Starlings (Sternus sinensis) that have been recorded breeding in the Disused Watchtowers close to the river confluence, and also to other avifauna and herpetofauna species that may breed within Luk Tei Tong Marsh.	River outlets during construction phase.	Contractor.		Ö			-
S7.8.5	Minimise Sedimentation All excavation works carried out within or close to water bodies should be carried out in the dry season where possible, with construction carried out by land-based plant. Excavation works within river/stream channels should be restricted to an enclosed dry section of the river, with containment measures such as bunds and barriers used within the river to minimize the impacts upon the downstream water body. Site runoff should be directed towards regularly cleaned and maintained silt traps and oil/grease separators to minimise the risk of sedimentation and pollution of river water. The silt and oil/grease separators should be appropriately designed for the local drainage and ground conditions. To minimize leakage and loss of sediments during excavation in narrow channels, tightly sealed closed grab excavators should be deployed where material to be handled is wet.	Works areas during construction phase.	Contractor.		Ö			-
S7.8.6	Minimise Noise Impacts Noise mitigation measures including the use of quiet construction plant and temporary noise barriers should be implemented to minimise disturbance to habitats adjacent to the works areas.	Works areas during construction phase.	Contractor.		Ö			-
S7.8.7	General Site Practice Standard good site practice measures should be implemented throughout the construction phase. The measures should include: · Placement of equipment or stockpile in designated works areas and access routes selected on existing disturbed land to minimise disturbance to natural habitats and vegetation, particularly mature trees. · Construction activities should be restricted to work areas that should be clearly demarcated. The work areas should be reinstated after completion of the works. · Waste skips should be provided to collect general refuse and construction wastes. The wastes should be disposed of timely and properly off-site. · General drainage arrangements should include sediment and oil traps to collect and control construction site run-off. · Open burning on works sites is illegal, and should be strictly prohibited.	Works areas during construction phase.	Contractor.		Ö			-
S7.8.8	Minimise Operation Phase Disturbance Impacts The following measures are recommended to minimise potential impacts resulting from operational phase activities: · To minimise sedimentation, de-silting should be limited to the dry season (November-March). · For maintenance desilting of the re-profiled river channels, temporary barrier walls shall be used to provide a dry zone for desilting work. · The implementation of de-silting and other activities that could disturb aquatic fauna should be phased to ensure some areas of relatively undisturbed habitat remain available for resident aquatic fauna at all times. · Waste material produced during de-silting should be disposed of in a timely and appropriate manner.	River Channels during operation phase.	Maintenance Agent.			Ö		-
S7.8.9- S7.8.11 S7.8.19- S7.8.23	Luk Tei Tong Bypass Channel To minimise impacts to Luk Tei Tong Marsh, No footpath would be constructed along the bypass channel. Construction of the Bypass Channel would be limited to one dry season only, thereby minimising disturbance impacts to wetland fauna potentially breeding in the Marsh Area. Operation phase impacts resulting from desilting works within the LTT Bypass Channel are expected to be very minor in scale, given that water flow (and therefore sediment deposition) within the channel would be minimal for much of the year, except during spate events. Vegetation control would be required 1-2 times per year at most to prevent the excessive growth of (especially woody) vegetation that would impede the drainage capacity of the channel. These measures do not necessarily conflict with the maintenance of the channel as marshland, as the removal and control of vegetation would be required anyway to maintain the sub-climatic vegetation community found in marsh habitats. It is recognised, however, that regular cutting of vegetation could prevent the re-establishment of wetland communities, with potential disturbance to breeding fauna of particular concern. It is therefore recommended that vegetation control is undertaken outside of the main breeding season for wildlife (April-August) to avoid potential impacts. The following key features would be included in the Channel design: · The Bypass Channel bed would be approximately 800mm below the existing ground level, and would be lined with turf taken from areas of Luk Tei Tong Marsh that fall within the footprint of the proposed Channel. This area would be maintained as compensatory marshland habitat. So as to maintain the flood protection function of the channel, vegetation within the Channel would be maintained at a height of about 300mm. · A low weir would be constructed at the downstream end of the Bypass Channel, serving to retain rainwater and some diverted floodwaters in the Channel. As the channel would be slightly lower than the existing ground level, and water within the channel would be retained, it is anticipated that habitats within the channel provide a more valuable wetland habitat than adjacent areas of Luk Tei Tong Marsh, where wetland vegetation is not particularly well established. · The banks of the proposed Channel would be lined with rock-filled gabion, and topped with small (200mm high) earth bund. The gabion lining is required to stabilize the banks of the Channel, and the earth-bund would prevent surface water from surrounding areas of the marsh from draining into the Channel. The intention of re-using turf from the channel alignment is to provide suitable soil conditions for wetland habitats within the Bypass Channel. Additionally, roots and seeds of some plant species within the turf would speed up the establishment of wetland vegetation within the Channel. It should be noted though that parts of the Channel alignment are currently dominated by the weed Mikania micrantha, which would require removal prior to the construction phase. Reference should be made to Nature Conservation Practice Note No. 01/2003. The construction of the LTT By-pass Channel is expected to take approximately 5 months. There is some concern that during this period, vegetation in sods of turf removed from the channel alignment would suffer some die-back before being replaced within the channel. To minimize potential die-back, it is recommended that turf removal (and channel construction) is limited to sections no more than 100m in length. The construction sequence would involve excavating the first 100m of the channel (at the downstream end of the alignment). Turf from this section would be moved to a temporary storage area. To minimize potential damage to this vegetation, the turf would not be stacked in layers during storage, and would be adequately watered for the duration of the storage period (i.e., 1-2 times daily). Following removal of the first 100m of turf, the second 100m of the channel would be excavated, and turf from this section immediately installed in the first excavated section of the channel. This process would be repeated until the last section of the channel is excavated. Turf removed from the first 100m section and stored during the construction would be used to re-vegetate this area. Even if some die-back occurs, it is expected that the roots and seed-bank within the turf will provide adequate material for the re-generation of vegetation following re-introduction into the LTT Bypass Channel. Furthermore, vegetation from adjacent areas of the marsh would also be expected to re-colonise substrates within the Channel, which would provide a suitable growing medium for vegetation recorded from the marsh area. A programme would be established to monitor the ecology (including vegetation communities) of the LTT By-pass Channel during the operation phase. If there appears to be any problem with vegetative re-establishment, remedial measures (including the planting of riparian/emergent /aquatic vegetation) would be implemented. The new wetland area within the Bypass Channel would cover an area of approximately 0.6ha. Although this would be slightly smaller than the 0.8ha of existing habitat affected by the improvement works, wetlands provided within the channel alignment would be of higher ecological value than the habitats they would replace, providing adequate compensation for habitat loss. Temporary works areas adjacent to the Bypass Channel alignment would be re-instated with the planting of appropriate wetland plant species following the completion of construction works. No long-term impact to these areas are expected.	LTT Bypass Channel	Project Proponent, Contractor, Maintenance Agent	Ö	Ö	Ö		-
S7.8.12	Minimise Impacts to Trees by Ling Tsui Tau U-Channel To minimise impacts to woodland habitats, the alignment of the proposed U-Channel should avoid nearby mature trees as far as practicable.	Ling Tsui Tau U-Channel during design/construction phase.	Project Proponent/ Contractor.	Ö	Ö			-
S7.8.13- S7.8.14	Capture-Surveys of Fish and Amphibian Species of Conservation Interest Proposed works at the rivers have the potential to impact fish species of conservation interest. To minimize these potential impacts, it is recommended that capture-surveys of the proposed works areas are conducted prior to the commencement of construction works in the channel. These surveys should include fish species of conservation interest recorded during the surveys (Flagtail, Kuhlia marginata & Predaceous Chub, Parazacco spilurus), with particular attention paid to the Flagtail. Either of these species caught during the surveys should be re-located to areas of the watercourse upstream of the proposed works areas, or to aquaria set up close to the works areas. Maintenance of the fish prior to translocation would be undertaken by an ecologist appointed by the Project Proponent. The capture surveys should be conducted in the dry season by a suitably qualified ecologist(s) appointed by the Project Proponent. For the Flagtail (which will probably occur in low densities at PNH River), further surveys should be conducted to confirm the presence and numbers of fish in the streams closer to the time of construction. A detailed methodology for fish translocation (based in part upon the Flagtail survey results) should be formulated during the detailed design stage of the Project. In addition to fish species of conservation interest, the proposed drainage improvement works could also result in direct impacts to two amphibian species of conservation interest, RTF and Chinese Bullfrog. It is therefore recommended that additional capture surveys are conducted prior to the commencement of works to locate any individuals of these two species within the works areas. The surveys should be conducted in the wet season (March/April-October), when these species are calling and are generally more conspicuous. Any individuals captured during the survey should be relocated to similar nearby habitats outside of the works areas. The capture surveys should be conducted by a suitably qualified ecologist(s) appointed by the Project Proponent. A detailed methodology for faunal translocation should be formulated during the detailed design stage of the Project.	Works areas prior to construction activities. Maintenance throughout construction phase.	Ecologist.	Ö	Ö	Ö		-
S7.8.24	Compensatory Tree and Shrub Planting Planting of trees and other vegetation along the banks of the newly created channels would provide compensation for unavoidable tree-felling and loss of small areas of open and secondary woodland habitat resulting from the proposed TTT and PNH River Channel and Ling Tsui Tau U-Channel works. Compensatory planting would make use of native plant species with flowers/fruits attractive to wildlife. Compensation in terms of woodland area and trees planted would be on at least a 1:1 ratio, covering an area of at least 0.13ha.	Detailed landscape design during design phase, planting during construction phase.	Designer/Contractor.	Ö	Ö			-
S7.10.1- S7.10.7	Environmental Monitoring & Audit The proper implementation of recommended ecological mitigation measures should be audited. A specific monitoring programme of improved sections of PNH and LTT Rivers is recommended. The programme should provide data on the re-establishment of aquatic/riparian communities in the channels, and allow an assessment of the relative success of mitigation measures to be made. Baseline data should be collected several months before the commencement of the construction phase, with monitoring conducted on a monthly basis during the construction phase, and every two months a year for 4 years after the completion of works. Data collected should include the following parameters: § Water quality (e.g., dissolved oxygen, pH, conductivity, salinity, BOD, nutrient concentrations); § Sediment characteristics; § Water flow; § Avifauna species and densities; § Aquatic macroinvertebrate community species composition and abundance; § Fish community species composition and abundance; § Adult odonate community species composition and abundance; § Aquatic, emergent and riparian vegetation community species composition and abundance. Reports on the findings of each monitoring trip should be submitted to Agriculture, Fisheries and Conservation Department (AFCD) for review. A final report summarising the monitoring results over the entire monitoring period should be prepared to serve as a reference for future projects of this kind. Monitoring should be conducted by a qualified ecologist(s) with over 6 years relevant experience. Monitoring of the LTT Bypass Channel would be required to confirm that the proposed Channel design has provided suitable compensation for impacts to Luk Tei Tong Marsh. It is suggested that ecological monitoring of habitats within the Channel should be undertaken for a period of at least 4 years. Data collected should include the following key parameters: § Water quality (e.g., dissolved oxygen, pH, conductivity, salinity, BOD, nutrient concentrations); § Sediment characteristics; § Water depth and flow; § Avifauna species and densities; § Aquatic macroinvertebrate community species composition and abundance; § Fish community species composition and abundance; § Herpetofauna community species composition and abundance; § Adult odonate community species composition and abundance; § Aquatic, emergent and riparian vegetation community species composition and abundance. To provide baseline data, it is suggested that the same parameters are measured along a strip of existing marsh habitat adjacent to the Channel alignment. A comparison of species diversity and densities along the Bypass Channel alignment and at the reference site would allow the effectiveness of habitat creation to be assessed. Monitoring of both the Channel and Reference Site should be conducted 6 times a year for 4 years after the completion of works. Reports on the findings of each monitoring trip should be submitted to AFCD for review. A final report summarising the results of monitoring over 4 years should be prepared to serve as a reference for future projects of this kind. Monitoring should be conducted by a qualified ecologist(s) with over 6 years relevant experience. The newly constructed PNH and LTT River Channels, and LTT Bypass Channel are expected to provide a similar habitat to the habitats they would replace. It is therefore anticipated that wildlife found in the existing rivers and marsh would successfully re-colonise the new channels. However, if the post-construction phase monitoring demonstrates that re-colonisation is unsuccessful the following contingency plan should be implemented: · Baseline/reference data should be compared with post-construction phase data. Any substantial differences in habitat characteristics (e.g., water quality, aquatic/emergent vegetation) should be noted. · The potential cause of differences between baseline/reference and post-construction phase habitat characteristics (e.g., changes in water depth, sediment characteristics) should be identified. · Measures to further rehabilitate the habitat characteristics of the channels should be implemented. Such measures could include: - Minor re-profiling of the channel bed(s) could be implemented to increase micro-habitat diversity within the channels. By excavating small areas of the bed, areas of slow flowing water would be created within river habitats, and small pools of very slow-flowing or standing water would be created within the marsh. - Increasing heterogeneity of substratum would again increase micro-habitat diversity: providing substrates of different sizes would provide niches for organisms preferring small sediments (e.g., burrowing dragonfly larvae) and larger cobbles/boulders (e.g., Heptageniid mayfly nymphs). - Planting of suitable aquatic, emergent and riparian vegetation could serve to increase vegetative cover. - Management of water levels within the LTT Bypass Channel could be implemented by modifying the height of the weirs at either end of the Channel; thus optimizing conditions for wetland habitat establishment within the Channel. · Further monitoring of abiotic and biotic parameters should be conducted to determine the relative success of the contingency habitat rehabilitation measures. A specific monitoring programme for the White-shouldered Starlings is recommended. A qualified ecologist with over 6 years relevant experience should conduct the monitoring. Monthly baseline surveys of the Disused Watchtowers should be undertaken in the wet season prior to the commencement of construction phase activities. The aim of baseline surveys should be to establish whether or not any breeding Starlings are still present. If breeding activities are identified, the number of breeding pairs, the success of breeding and responses to any disturbance should be recorded. During the construction phase, monthly surveys of the Watchtowers are recommended. Information should be collected on behaviour, breeding activity, and any response to disturbance. The source of any disturbance impacts should be identified.	Prior to and during Construction Phase. Operation Phase.	EM Team and Ecologist(s).	Ö	Ö	Ö		-

# All recommendations and requirements resulted during the course of EIA/EA Process, including ACE and / or accepted public comment to the proposed project.

* Des - Design, C - Construction, O – Operation, and Dec - Decommissioning