12 conclusions and environmental outcomes

12.1 Introduction

12.1.1 This EIA Report is prepared in accordance with the Environmental Impact Assessment Study Brief No. ESB-088/2001. The proposed project is a Designated Project under Schedule 2 Part I of the EIAO and requires an environmental permit under the EIAO for its construction and operation. This Section presents a summary of the key potential environmental outcomes associated with the construction and operation of the Project.

12.2 Drainage Options, Alignment and Construction Method

12.2.1 For the Sai Kung River upstream section, two small sections of Pak Kong River and Ho Chung Channel, the existing stream courses will be improved. The area of land resumption and the extent of village house resumption will be largely reduced such that disruption to local people would be kept to minimum.

12.2.2 For the Sai Kung River downstream, catchment diversion scheme will be adopted. It will avoid major disruption to the local residents and traffic by construction of new culvert to divert flood flow from Sai Kung River to the Sha Ha River. Major improvement works at Sai Kung Town will not be required.

12.2.3 For Pak Kong, full-scale training is considered the most effective solution to resolve the flooding problem. However, during the consultation meetings, the local residents requested to minimise the extent of works as far as possible in order to avoid resumption of their houses. They would accept a higher flooding risk as a trade-off. As compromised with the local residents, this project will only re-construct two existing bottlenecks and stabilise an existing channel slope adjacent to Hiram’s Highway. After completion of the works, flooding problem will persist.

12.2.4 The potential environmental impacts would be localised and limited to the construction stage. With the recommended appropriate construction methods and the implementation of necessary mitigation works during the construction stage, the potential environmental impacts would be kept to minimum and acceptable levels.

12.2.5 The potential impacts on social, economical and environmental aspects have been duly considered when determining the drainage options, alignments and construction methods in this EIA. It is concluded that the proposed drainage works would strike a balance between the environmental, economical and social aspects. The proposed drainage works would provide a cost-effective, environmentally and socially acceptable method to address the flooding problems in Sai Kung, Pak Kong and Ho Chung.

12.2.6 Environmental friendly design has been adopted in the channel design. The impact to ecological aspects would be mitigated to acceptable levels.

12.3 Construction Air Quality Impact

12.3.1 With the adoption of the recommended mitigation measures, this assessment has indicated that the dust criteria would be complied at all the ASRs during the drainage improvement works. Mitigation measures and EM&A requirements have been recommended to minimise potential nuisance from the work. Measures such as good construction practices as required under the Air Pollution (Construction Dust) Regulation should be followed to ensure the dust level to be within the criteria. Potential dust impacts from the Project are hence expected acceptable. For odour impact, it would be minimised by the proposed mitigation measures and would be within acceptable levels.

12.4 Construction Noise Impact

12.4.1 Noise arising from the construction activities of the Project would have potential impact on the NSRs located in the vicinity of the work sites. The unmitigated cumulative construction noise levels ranging from 65 dB(A) to 97 dB(A) were predicted at the representative NSRs. In short, the predicted noise levels at all the NSRs would exceed the EIAO-TM noise assessment criteria without mitigation.

12.4.2 Sufficient noise control measures would be required to mitigate the potential construction noise impacts. The recommended mitigation measures include: adopting quiet construction plant; using movable and temporary noise barriers; and implementing good site practices.

12.4.3 With the recommended control measures in place, the mitigated noise levels at all the NSRs due to the proposed Project would comply with the daytime construction noise assessment criteria as set out in the EIAO-TM.

12.4.4 An EM&A programme would also be implemented to monitor construction noise impact.

12.4.5 In terms of interfacing with other projects, an assessment was undertaken for cumulative noise impact arising from this Project and the “Improvement work of Ho Chung Road”. Assessment results indicated that the cumulative noise levels at NSRs would comply with the construction noise assessment criteria of 75 dB(A) stipulated in the EIAO-TM.

12.5 Water Quality Impact

12.5.1 The key issue in terms of water quality would be related to excavation works during the construction phase of the proposed drainage improvement works in Sai Kung. To minimise potential impacts on water quality during the channel construction, special working method controls have been recommended for the proposed works at Sai Kung River, Pak Kong River and Ho Chung Channel. In particular, excavation works for the earth channels would be carried out in dry conditions by diverting the stream flow from upstream of the site. Containment measures would also be used within the channel to prevent water from entering the excavation area.

12.5.2 Other potential sources of water quality impact would comprise construction site runoff and drainage; debris, refuse and liquid spillages from general construction activities; and sewage effluents from the construction workforce. Minimisation of water quality deterioration could be achieved through implementing adequate mitigation measures such as control measures on site runoff and drainage from the works areas to minimise construction run-off. Proper site management and good housekeeping practices would also be required to ensure that construction wastes and materials would not enter the downstream watercourses. Sewage effluent arising from the construction workforce would also require appropriate treatment through provision of portable toilets.

12.5.3 With implementation of the recommended mitigation measures, the construction works for the proposed drainage improvement works would not be anticipated to cause unacceptable impacts on water quality.

12.5.4 As an additional level of protection, water quality monitoring and audit would be carried out to detect any deterioration of water quality during the construction phase and to initiate any necessary mitigation actions.

12.6 Waste Management Implications

12.6.1 The main waste arising during the construction phase would be the excavated materials from the river improvements works at Sai Kung River, Pak Kong River and Ho Chung Channel. The excavated materials would comprise soil, sand, gravel and small rocks. It was recommended that the excavated materials with suitable characteristics be reused on-site, as far as practicable, for example as the fill materials for backfilling of temporary drainage channels or construction of embankments. Surplus excavated soil, sand, gravel and rock materials would require disposal to a public filling area.

12.6.2 Other wastes generated by the construction activities are likely to include general refuse from the workforce, chemical wastes from plant and vehicle maintenance, and C&D material from the demolition of existing structures and site clearance. Provided that these identified waste arisings are to be handled, transported and disposed of using the recommended methods and good site practices are to be strictly followed, adverse environmental impacts would not be expected during the construction works. The recommended mitigation measures should form the basis of the Waste Management Plan to be developed by the Contractor.

12.7 Land Contamination

12.7.1 An account of the present and historical land uses, in accordance with ProPECC PN3/94, along the proposed drainage improvement areas of the three river channels indicated that activities related to land contamination impact were not identified in or near to Sai Kung River and Ho Chung Channel. However, workshops associated with potentially contaminating uses were found near Pak Kong River and the main type of identified activities was associated with car repairing works.

12.7.2 Considering the potential land contamination impact to site workers during construction of the Project, a detailed site investigation was recommended for those areas falling within the project boundary after land resumption. According to the preliminary design of Pak Kong River, only partial areas of the two workshops are located within the project boundary which might lead to land contamination impact. A preliminary Contamination Assessment Plan (CAP) has been prepared for further investigation.

12.7.3 Due to the possible changes of land use and site conditions, a review of the preliminary CAP would be required by the future Environmental Team at a later stage after land resumption. It is considered that potential residual impacts would not be significant provided that any identified contaminated land would be remediated to the acceptable standards prior to the site clearance/excavation works taken place, and the mitigation measures recommended be properly implemented during the construction stage of the Project.

12.8 Ecological Impact

12.8.1 Nine-month ecological surveys covering the wet and dry seasons were undertaken to establish the ecological profile of the Sai Kung & Sha Ha, Pak Kong and Ho Chung Assessment Areas.

12.8.2 The Assessment Areas included several areas (Conservation Areas, Coastal Protection Areas, Country Park/Special Area) of recognised conservation interest.

12.8.3 Seven major habitat types were identified within the Assessment Areas, comprising Rivers/Streams, Cultivation Land, Woodland and Fung Shui Woodland, Shrubland, Developed and Village Areas, Mangrove, and Marine Habitat. Several plant species of conservation interest were found in the Assessment Areas, including one rare tree species (Ehretia acuminata) recorded inside the proposed Ho Chung Works Area.

12.8.4 A total of 64 bird species were recorded in the Assessment Areas during recent surveys, 12 of which are considered of conservation interest. One fish, one snake, one butterfly and three mammal species of conservation interest were also recorded from the Assessment Areas during recent surveys.

12.8.5 The primary direct ecological impact resulting from the Project would be the loss of small sections of moderate ecological value lowland rivers. The proposed works are also anticipated to directly affect several individuals of the rare tree Ehretia acuminata.

12.8.6 Other direct impacts would include the loss of 0.83ha low-moderate value cultivation land and 0.91ha low ecological value village and developed area habitats. Because of the low ecological value of the affected habitats, these impacts are considered relatively minor.

12.8.7 Indirect impacts would be expected to include increased sedimentation in aquatic habitats during the construction phase, and disturbance to wildlife caused by increased human activity and noisy construction phase activities. Sedimentation is predicted to have only temporary and localised impacts to aquatic habitats, and is considered a minor ecological impact. Construction phase disturbance would be temporary, and would largely affect only low and low-moderate ecological value habitats. As such, it is considered a minor ecological impact.

12.8.8 Operation phase impacts are expected to be relatively minor.

12.8.9 Measures to avoid, minimise and compensate for identified ecological impacts have been recommended. These include measures to reduce minor construction phase impacts to aquatic communities resulting from increased sedimentation and disturbance. Additionally, individuals of the rare tree species Ehretia acuminata affected by the proposed works are recommended to be transplanted.

12.8.10 The design of drainage channels proposed to replace Sai Kung and Ho Chung Rivers includes the use of natural substrates for lining newly formed channel beds, recreation of natural riffle/pool sequences, use of rocked filled gabion to line newly constructed river banks, and extensive compensatory planting along the channel banks. With these measures in place, it is expected that aquatic communities found in the rivers would re-colonise the newly constructed drainage channels. No major long-term residual impacts to the rivers are anticipated.

12.8.11 With the implementation of the recommended mitigation measures, ecological impacts resulting from the proposed drainage improvement works are expected to be relatively minor and environmentally acceptable.

12.9 Landscape and Visual Impact

12.9.1 The landscape impacts on the landscape resources and character are predicted to be negligible during the construction and operation phases of the project in three out of the four landscape character areas identified in the landscape and visual impact assessment (LVIA), even without mitigation measures incorporated into the scheme. The landscape impacts on the landscape resources and character within the remaining landscape character area 2 (LCA2) are predicted to be moderate-adverse without mitigation measures, owing mainly to the loss of approximately 442 existing trees. The incorporation of landscape mitigation measures such as tree planting, the greening of slopes and channel edges would lessen the landscape impact to slight-moderate although overall the impact would remain adverse.

12.9.2 The unmitigated visual impact of the Project on views similar to Visually Sensitive Receiver 1 (VSR1) near a footpath at Muk Mun Shan is predicted to be slight-moderate adverse, owing to the loss of the surrounding vegetation and the construction of a below ground level channel. The unmitigated visual impact of the Project on VSR 2 near the Green House Nursery is predicted to be slight-moderate and adverse. The unmitigated visual impacts of the Project on viewer groups at VSR3 near Hiram's Highway are predicted to be moderate-significant adverse mainly owing to the intrusion of the new works into existing views. The unmitigated visual impact of the Project on VSR4 at Ho Chung Village is predicted to be slight-moderate adverse mainly owing to the loss of surrounding vegetation and the construction of the channel. It is predicted that through the incorporation of mitigation measures such as planting within the channel, textured concrete walling, and compensatory tree planting, adverse visual impacts can be reduced to slight adverse except for VSR3 where moderate adverse visual impact would be expected.

12.9.3 From a landscape planning perspective, the main impact of consequence is the residual landscape impacts within the LCA2 Lowland Valley where slight-moderate adverse impacts are predicted and at VSR3 where moderate adverse visual impacts are predicted. Despite the fact that the impacts cannot be mitigated to achieve a beneficial level from a landscape planning perspective, the presence of the drainage channels within a flat coastal landscape is not considered to be unacceptable.

12.10 Impact on Cultural Heritage

12.10.1 The desk-based review identified that there was no archaeological potential sites located in the Ho Chung and Pak Kong works areas. No adverse impact is identified for these two areas.

12.10.2 The desk-based review identified the works areas at Sha Ha as having potential for archaeological deposits. Upon completion of the Field Survey, the results however indicated that the deposits in the works areas had been reworked and in-situ archaeological material had been redeposited. The finding reveals that no in-situ archaeological deposits remain within the Sha Ha works area and no adverse impact is therefore identified.

12.10.3 The proposed drainage works would have some minor effects on built heritage features recorded in the survey. The following measures are recommended to be adopted in the construction and operation phases.

· Protective measures should be provided for the shrine if works are taken place in close proximity. The protective measures should consist of the following:

1) High visibility fencing at a distance of one meter around the shrine.

2) Heavy duty plastic sheeting to be placed over the exterior surfaces of the shrine for duration of ongoing works.

· Che Kung Temple and second earth god shrine: a vehicle parking area should be maintained or alternative parking facilities should be made available. Clear signage for directions to the Temple should be provided from Hiram’s Highway;

· Felling of mature trees along all three rivers should be avoided. If it is unavoidable, any trees that are removed from the area should be replaced by trees of the same species.

· The channel design should also include proposals for designs that will minimise any change in character to the environmental setting, such as the incorporation of building materials for the channelisation, that are compatible to the existing environment, such as cobbles and gravel and the incorporation of features that will encourage vegetation growth along the banks, such as grass concrete and natural verges.

12.11 Environmental Monitoring and Audit

12.11.1 During construction of the Project, environmental monitoring will be necessary to assess the effectiveness of measures implemented to mitigate potential noise, water, land contamination, ecology and landscape and visual impacts. Regular environmental auditing is also recommended to ensure that potential impacts from other sources are adequately addressed through the implementation of the mitigation measures defined in this EIA Report.

12.12 Public Consultation and Continuous Public Involvement

12.12.1 The public consultation exercise for the proposed Project with concerned groups and parties such as local residents, Village Representatives (VR), Rural Committee Members, District Council, green groups and all interested parties in addition to the relevant statutory and advisory bodies was conduced from October 2003 to June 2004.

12.12.2 Apart from the local residents of Pak Kong who objected the proposed drainage works in Pak Kong River due to the need of land and houses resumption on both sides of the river banks, there are no adverse comments on the proposed drainage improvement project from the consulted parties.

12.12.3 As requested by the Pak Kong local residents, the scope of the works were agreed to be reduced to the re-construction of two existing bridges and stabilisation of existing river slope adjacent to Hiram’s Highway. A summary of the public consultation conducted and their outcomes is shown in Table 12.1.

Table 12.1 Summary of Public Consultation Conducted

Date	Subject	Outcomes
20 Oct 03	Public Consultation Meeting with VRs (Sha Ha, Sha Kok Mei, Pak Kong, Tai Chung Hau and Ho Chung)	VRs supported the drainage improvement project. Ho Chung VR requested a joint site inspection.
3 Nov 03	Public Consultation Meeting with Ho Chung VR and Villagers	Villagers requested to retain the existing overflow weir and the general layout was revised accordingly.
2 Dec 03	Public Consultation with Tai Chung Hau VR and Villagers	Review the drainage improvement works. Public objected full-scale training.
8 Dec 03	Public Consultation with Sai Kung Rural Committee	SK Rural Committee supported the drainage improvement project.
17 Feb 04	Public Consultation with Tai Chung Hau VR and Villagers	The scope of works was reduced from full-scale training to widening of two bottlenecks and stabilization of existing slope. The public accepted the existing flooding risks.
24 Feb 04	Public Consultation with Sai Kung District Council	Sai Kung District Council supported the drainage improvement project.
30 Apr 04	Public Consultation with Green Groups (Conservancy Association, Green Power, World Wild Fund)	The channel design was advised to be reviewed in order to include ecological friendly design.
11 Jun 04	Public Consultation with Green Groups (Conservancy Association, Green Power, World Wild Fund)	Gabion lining, planting pits, pools and riffles were proposed to be included into the channel details. The existing river will remain untouched as far as possible. Green Power and WWF welcomed the revised details.
16 Jun 04	Public Consultation with the Conservancy Association	Gabion lining, planting pits, pools and riffles were proposed to be included into the channel details. The existing river will remain untouched as far as possible. Conservancy Association welcomed the revised details.

12.13 Overall Conclusions

12.13.1 The EIA has assessed the overall acceptability of environmental impacts likely to arise as a result of the construction and operation of this Project. Where necessary and practicable, the EIA has specified the conditions and requirements for the detailed design, construction and operation of the Project in order to mitigate environmental impacts to acceptable levels.

12.13.2 This EIA Study has predicted that the Project would comply with relevant environmental standards and legislation after the proposed mitigation measures are implemented. The EIA has thus demonstrated the acceptability of any residual impacts from the Project and the protection of the population and environmentally sensitive resources. Where appropriate, EM&A mechanisms have been recommended before and during construction to verify the accuracy of the EIA predictions and the effectiveness of recommended mitigation measures. Table 12.2 summarises the environmental outcomes/ benefits from the implementation of the Project as well as the associated mitigation measures proposed.

12.13.3 In conclusion, it is considered that the EIA provides a suitable basis for the Director of Environmental Protection to consider granting the Environmental Permit to allow the construction and operation of the Project.

Table 12.2 Summary of Key Environmental Outcomes/ Benefits

Issue	Environmental Outcomes/Benefits
The Project	· Relieve the risk of flooding · Minimise economic loss · Minimise disruption to everyday life especially during the wet season in Sai Kung and Ho Chung · The existing Pak Kong River would be less susceptible to flooding after improving the bottlenecks. No resumption of existing structures is required.
Drainage Options, alignment and Construction Methods	The following ecological-friendly design would be incorporated into the channel details in order to mitigate the environmental impact. · Natural riverbeds and substrates would be retained as far as practicable. New sections of riverbed would be lined with natural substrates instead of using concrete lining. · In new sections of riverbeds, substrates would be arranged to mimic the natural pool/riffle sequence of the existing river. · New riverbanks would largely be constructed of rock-filled gabion rather than concrete/grasscrete. Pits would be provided in the gabion for planting of riparian vegetation. · Compensatory planting provided to mitigate the loss of natural riparian vegetation. · A fish-ladder would be installed in the Ho Chung River to increase the range of fish species above and below existing weirs.
Construction Air Quality Impact	· Air Sensitive Receivers identified nearby the construction site are protected from construction air quality impact through implementation of mitigation measures: Sai Kung River and Sha Ha Diversion Culvert - Sha Kok Mei, Muk Min Shan, Tyburn House, Burlingame Garden and scattered village houses nearby the construction site (Figure 3.1 refers) Pak Kong River - Tai Chung Hau and scattered village houses nearby the construction site (Figure 3.2 refers) Ho Chung Channel - Ho Chung, Ho Chung New Village, Berkeley Bay Villa and Che Kung Temple (Figure 3.3 refers)
Construction Noise Impact	· Unmitigated cumulative construction noise levels: 65 dB(A) to 97 dB(A). · Affected Noise Sensitive Receivers include: Sai Kung River and Sha Ha Diversion Culvert - Sha Kok Mei, Muk Min Shan, Tyburn House, Burlingame Garden and scattered village houses nearby the construction site (Figure 4.4 refers) Pak Kong River - Tai Chung Hau and scattered village houses nearby the construction site (Figure 4.5 refers) Ho Chung Channel - Ho Chung, Ho Chung New Village, Berkeley Bay Villa and Che Kung Temple (Figure 4.6 refers) · All affected NSRs would be protected from construction noise by implementation of recommended mitigation measures, including adopting quiet construction plant; using movable and temporary noise barriers; and implementing good site practices. · No cumulative noise impacts and adverse residual noise impact would be expected.
Water Quality Impact	· Minimisation of potential impacts: working method controls recommended e.g. excavation works carried out in the dry conditions, and containment measures used within the channel. · Minimisation of water quality deterioration: implementation of adequate mitigation measures, proper site management and good housekeeping practices; and appropriate treatment of sewage effluents. · No unacceptable impacts on water quality would be anticipated.
Waste Management Implication	· Excavated material with suitable characteristics should be reused on-site as far as practicable (approx. 13,700 m^3). Surplus material would require disposal to a public filling area. · Other wastes generated by construction activities: general refuse from the workforce, chemical wastes from plant and vehicle maintenance, and C&D material from the demolition of existing structures and site clearance. · Surplus inert C&D material (i.e. public fill) generated from the Project is proposed to be disposed to the fill bank at TKO Area 137, and non-inert C&D material (i.e. C&D waste) is proposed to be disposed to the SENT Landfill. · With implementation of the recommended mitigation measures for the handling, transportation and disposal of the identified waste, no residual waste management impacts would be expected.
Land Contamination	· Two contaminative workshops identified with vehicle repairing activities encroach upon the project works area of Pak Kong River which may impose health and safety impacts to the construction workers. · No residual impact would be expected if the contaminated soil (if identified any in the recommended site investigation) would be remediated to the acceptable standards prior to the site clearance/excavation works.
Ecology	· The proposed works would provide flood protection to adjacent areas while minimising disturbance to existing river habitats. Various mitigation measures implemented during construction phase and the adoption of the environmentally sensitive channel design would serve to maintain the ecology of the existing rivers. · Channel design adopted at the Rivers has been considered to closely recreate existing river habitat conditions. Impacts to existing riverbeds would be avoided as far as practicable, thus maintaining existing ecological conditions. Natural materials (e.g., cobbles and small boulders) would be used to line new sections of riverbed, the riffle/pool sequence of existing river channels would be re-created, and rock-filled gabion blocks would be used to line new riverbanks as far as possible. · Measures to enhance existing ecological conditions along the rivers have been incorporated where possible. These would include the installation of a fish ladder at Ho Chung River to aid the passage of fish communities above and below an existing weir, thereby extending the range of fish communities along the whole river. · Following a period of establishment and re-colonisation, the newly created channels are expected to provide a suitable habitat for aquatic communities recorded in the existing rivers. · The loss of riparian vegetation would be compensated for through the extensive tree/shrub planting along the river banks (with at least as many trees planted as felled), planting of herbaceous riparian vegetation within reconstructed gabion bank lining, and natural colonisation of parts of the channel base by grasses, herbs and low shrubs. · Further planting of woodland tree and shrub seedlings would be implemented within areas adjacent to the newly constructed channels. · Compensatory planting would make use of native plant species with flowers/fruits attractive to wildlife.
Landscape and Visual Impact	· Loss of approximately 442 existing trees. · The incorporation of landscape mitigation measures such as tree planting, the greening of slopes and channel edges would lessen the landscape impact. · The incorporation of mitigation measures such as planting within the channel, textured concrete walling, and compensatory tree planting, will reduce adverse visual impacts to slight adverse except for one location where visual impact cannot be mitigated lower than moderate adverse. · The presence of the drainage channels within a flat coastal landscape is not considered to be unacceptable.
Impact of Cultural Heritage	· No adverse impacts on archaeological resources within the study areas of the proposed drainage improvement works. · Minor effects on built heritage features were found but no residual impact would be expected with implementation of recommended mitigation measures during the construction and operation phases.