Contents

1                      Introduction                                                                          

1.1                   Project Background                                                        

1.2                   Need of the Project                                                           

1.3                   Objectives of the EIA Study                                            

2                      Project Description                                                           

2.1                   Existing Environment                                                         

2.2                   Consideration of Alternatives                                    

2.3                   Project Design                                                                      

2.4                   Construction Programme                                              

2.5                   Maintenance Dredging                                                      

3                      Summary of Environmental Impacts                          

3.1                   Introduction                                                                          

3.2                   Air Quality                                                                                

3.3                   Noise                                                                                           

3.4                   Water Quality                                                                        

3.5                   Terrestrial Ecology                                                         

3.6                   Fisheries                                                                                    

3.7                   Waste Management                                                             

3.8                   Land Contamination                                                            

3.9                   Cultural Heritage Impact                                               

3.10                 Landscape and Visual Impact                                        

3.11                 EM&A Requirement                                                               

3.12                 Overall Conclusion                                                           

 

1                                            Introduction

1.1                                      Project Background

Shenzhen River is the boundary river between the Hong Kong Special Administration Region (HKSAR) and the Shenzhen Special Economic Zone.  In order to prevent serious flooding in the vicinity and improve the livelihood of residents on both sides, the government of the HKSAR and the Shenzhen Municipal Government have jointly completed the Shenzhen River Regulation Program Stages 1, 2 & 3 between 1997 and 2006.  About 13.67 km in length of Shenzhen River, starting from the confluence with Ping Yuen River to the river mouth, has been regulated under the first three stages of regulation program.

The purpose of the Stage 4 regulation program is to upgrade the flood protection standard of the Shenzhen River.  In addition, the regulation program will also tie in with the development of the proposed Liantang / Heung Yuen Wai (LT/HYW) Boundary Control Point (BCP).  The proposed Stage 4 of the regulation program will continue the works of Stage 3 regulation program starting from the Ping Yuen River to about 1.4 km upstream of the proposed LT/HYW BCP (a total of about 4.5 km of Shenzhen River will be regulated) (hereafter “the Project”).  In addition, associated with the river training works, the existing boundary patrol road and boundary fence of about 4.5 km in length running alongside the concerned river section are required to be realigned.  The location and alignment of the Project site is shown on Figure 1.1.

Changjiang Water Resources Protection Institute (CWRPI 長江水資源保護科學研究所) in association with ERM-Hong Kong Ltd was jointly commissioned by the Shenzhen River Regulation Office of the Shenzhen Municipal Government (深圳市治理深圳河辦公室) and the Drainage Services Department of the HKSAR to undertake the Regulation of Shenzhen River Stage 4 EIA Study (the Assignment).  This Executive Summary summarizes the key findings of the EIA related to the requirements of the Hong Kong side.

1.2                                      Need of the Project

The catchment of the Shenzhen River comprises a “fan-shaped” system, characterised by short and steep upstream rivers.  Large flow from these rivers can converge into Shenzhen River within a short time.  During heavy rain storm, the flood peak can reach the downstream section of Shenzhen River within a few hours.  The flooding risk of the Shenzhen River is particularly prominent at times of heavy rain associated with typhoon, where the high sea level suppressed the water discharge from Shenzhen River.  Prior to the regulation of Shenzhen River, frequent flooding occurred along the river.  Since the completion of the Stage 3 regulation works, the flood prevention ability of Shenzhen River is enhanced and the flooding frequency is reduced.

The section of the Shenzhen River to be regulated under this Project is relatively flat, narrow and winding.  The width of the river is uneven and erosion can be found along the river bed and river banks.  Some sections of the river embankment have collapsed.  The current flood prevention performance are in the range of 1 in 2 to 1 in 20 years, which cannot meet the standard in the PRC National Standard (1 in 20 to 50 years) or the Hong Kong Standard (1 in 50 years). 

Figure 1.2 shows the predicted flood extent of a 1 in 50 years flood event.  As shown in Figure 1.2, the extent of the flood will encroach into the villages along Shenzhen River, including Ta Kwu Ling Village, Kaw Liu Village, Chuk Yuen Village, Tsung Yuen Ha Village, as well as the boundary patrol road and part of the Lin Ma Hang Road.  Hence, there is a need to carry out the Project to rectify the flood prevention performance of this section of the Shenzhen River and to safeguard the livelihood of settlements and boundary security along the river.  In addition, the Project will be required to meet the required flood protection standard for the proposed LT/HYW BCP development.

1.3                                      Objectives of the EIA Study

The Project is classified as a Designated Project under Item I.1, Part 1, Schedule 2 of the EIA Ordinance and therefore the construction and operation of the Project will require an Environmental Permit. 

The overall objectives of the EIA Study are to provide information on the nature and extent of environmental impacts arising from the Project; to recommend appropriate mitigation measures to control the potential environmental impacts so that it complies with the requirements of the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM); and to confirm the environmental acceptability of the Project.  Key environmental issues identified in the EIA Study Brief include air quality, noise, water quality, ecology, fisheries, waste management, land contamination, cultural heritage and landscape and visual impacts.

The EIA was conducted in accordance with the guideline on assessment methodologies provided in the EIAO-TM.  The general approach for the assessment includes description of baseline environmental conditions for the impact assessment, identification and evaluation of potential impacts and recommendation of mitigation measures and an environmental monitoring programme.  The assessments in this EIA Study are conducted using well-proven and internationally accepted methods based on reasonable worst-case conditions.

2                                            Project Description

2.1                                      Existing Environment

Shenzhen River is the drainage outlets of various watercourses in Shenzhen and Hong Kong.  The main tributaries on Shenzhen side include Wu Tong Shan Stream (梧桐山溝), Jing Du Stream (徑肚溝), Chang Ling Stream (長嶺溝) and He Jiao Long Stream (禾叫壟溝) and on Hong Kong side include Ping Yuen River (River Ganges) and Kong Yiu Drainage Channel.

On Hong Kong side, the Project Site is located at rural area entirely within the Frontier Closed Area in the New Territories.  The surrounding environment consists of mainly abandoned agricultural fields and scattered rural village houses.

2.2                                      Consideration of Alternatives

2.2.1                                Design Return Period

The relevant legislation and guidelines in both Mainland China and HKSAR will be followed in setting design criteria for the Project.  In accordance with the PRC National Standard Flood Prevent Standard (GB 50501-94) and Urban Flood Prevent Engineering Design Standard (CJJ50-92), the design return period for Shenzhen River should be between 20 to 50 years.  Whist in Hong Kong, the Stormwater Drainage Manual published by the DSD recommended that the design return period based on flood levels should be 50 years for main rural catchment drainage channels.  With reference to the above relevant legislation and guidelines and the design criteria adopted in the Stage 1, 2 & 3 regulation works, the governments of the two cities have agreed that the flood prevention measures to be implemented for the Stage 4 regulation works shall be designed to attain the drainage capacity of a 50-year return period.

2.2.2                                Flood Prevention Measures Analysis

The flood prevention measures considered during the feasibility study include flood storage, flood diversion and river modification.  These measures were compared against their effect on flood prevention and land and environmental limitations.  Based on the preliminary assessment of different flood prevention measures, a combination of river modification works and flood storage was taken forward to study the preferred option for the Stage 4 regulation works.

2.2.3                                Design Options

The design principle of the works is to protect the livelihood of residents on both sides of the river with an ecological sensible design, which should maintain the naturalness of the river and riparian habitats and hence protect the biodiversity.  The design and layout planning of the works should be compatible with the future LT/HYW BCP.  Two design options were then developed for further study:

Option A:  The existing alignment of the concerned section of the Shenzhen River will be maintained as far as practical and massive excavation, dredging or filling will be avoided.  Different designs such as trapezoidal, vertical or compound channel will be used with reference to the existing conditions.  The centerline of the concerned section of the Shenzhen River will be about 4.5 km in length and a flood retardation pond will be constructed with a storage capacity of 80,000 m3.  The river side slope will be at the ratio of 1:2 to 1:5 and the standard bottom width of the riverbed will be in a range of 14 to 32m.

Option B:  The concerned sections of the Shenzhen River will be straightened and widened.  The centerline of the concerned section of the Shenzhen River will be about 4.5 km in length and a flood retardation pond will be constructed with a storage capacity of 80,000 m3.  The regulation works will mainly in the form of trapezoid open channel with side slope at the ratio of 1: 3.  The standard bottom width of riverbed will be in a range of 14 to 16m.

The two options were evaluated against the aspects of land requirement, environmental consideration, management and maintenance during operation and cost.  Both Option A and Option B are designed to attain the drainage capacity of a 50-year return period.  The management and maintenance of both options will be simple and in low costs and the design and layout planning of both options will be compatible with the proposed LT/HYW BCP.  Option A will preserve the existing river alignment and will provide diversified river and riparian habitats after the modification.  It requires less additional land than Option B especially the use of land in Hong Kong.  The capital cost of Option A is less that that of Option B.  As a result, Option A is preferred in terms of land requirement, environmental consideration and cost implication and will be adopted as the design scheme for detailed design and EIA Study.

2.2.4                                Construction Sequence and Methodology

The reprovision of boundary patrol road on Hong Kong side will commence before the river modification works for security reason.  The road sections near the LT/HYW BCP development will be constructed first in order to tie in with the BCP development.

The river modification works will be carried out in four phases, commencing from the downstream section of the river.  Two phases will be carried out in parallel.  This approach will strike a balance between the need to control the magnitude of environmental impact at the same time while not hindering the overall programme of the Project.  Heavy rains during wet and typhoon seasons will increase the quantity of site runoff during construction.  In order to minimize the potential water quality impacts, river excavation works will be arranged to be conducted in dry seasons (November to March of the following year).

River sediment will need to be dredged during the river modification work.  Due to the site constraints and the shallow water depth, the use of dredging barge in this Project is not feasible.  Land based dredger will be used.

With regard to river bed excavation, instead of directly excavating the river bed, which will generate sediment plume release to the river water throughout the excavation period, the excavation of river bed for this Project will be carried out within a cofferdam made of hessian bags.  By implementing this method, the cofferdam will block the sediment released into the river during the excavation work, thus minimising the water quality impact.  River diversion work will be carried out before the commencement of excavation and construction works.  When the excavation and placement of embankment foundation are carried out on one side, the river course on the other side will be used as a diversion channel.  This method will ensure the seamless flow of water along the river and minimise the disruption of hydrology of the river.

2.3                                      Project Design

The location and alignment of the Project components are shown in Figure 2.1 to 2.5.  The scope of the Project comprises:

·           Improvement of an approximately 4.5km long section of Shenzhen River;

·           Re-provision of a boundary patrol road and about 4.5km of boundary fence;

·           Dry weather flow interception along Shenzhen side of the river; and

·           Associated landscaping works.

2.3.1                                River Modification Works

Under the proposed Stage 4 regulation, about 4.5km section of the Shenzhen River will be regulated.  The work starts from the confluence with Ping Yuen River (ie the endpoint of Stage 3 regulation works) and will pass through the Luo Fang Sewage Treatment Works, Luo Fang Bridge, Luo Fang Village, Sai Ling Village in Shenzhen and Kaw Liu Village and Chuk Yuen Village in Hong Kong, and ending near Pak Fu Shan in Hong Kong.

The design principle of the works is to protect the livelihood of residents on both sides of the river with an ecological sensible design, which should maintain the naturalness of the river and riparian habitats and hence protect the biodiversity.  As shown in Figures 2.1 to 2.5, the design alignment will follow the existing watercourse as far as possible to minimise alternation to the existing river profile and meandering nature, minimise landtake and avoid massive excavation and filling.  Moreover, the river bed will remain as natural bottom without concreting.  At several meandering locations with sharp bend, a floodplain will be created with the planting of existing species to resemble the naturalness of the river while achieving the required flood design standard.

A combination of trapezoid channel, compound channel and vertical sidewall will be used along the river alignment.  The proposed flood retardation pond will be located near Chuk Yuen Village, covering an area of 22,000 m2 with a storage capacity of 80,000 m3.  Overflow weirs will be used in the inlet and outlet of the retardation pond

2.3.2                                Reprovisioning of Boundary Patrol Road and Boundary Fence

The reprovisioning of boundary patrol road and boundary fences along the concerned section of Shenzhen River under the Stage 4 regulation has already been incorporated into the design and construction programme of this Project.

The design of boundary patrol road on Hong Kong side will be based on the Transport Planning and Design Manual and Guidance Note published by Transport Department of HKSAR.  The total length of the boundary patrol road to be reprovided under this Project is about 4.5km and the width will be 3.5m.  The boundary patrol road will be paved with asphaltic concrete.  Passing bays (12m long and 6m wide) will be provided at 200 to 300m intervals.  Boundary fences will be constructed on both sides of the boundary patrol road.  The height of secondary and primary fences will be 3.5m and 4.6m respectively and the primary fence will be equipped with security sensing system and barbed wire. 

The reprovisioning of the section of boundary patrol road and boundary fence along the section of Shenzhen River under this Study will be managed by DSD as an “Advanced Works” of this Project.  Currently, the Architectural Services Department (ArchSD) is managing the construction of a secondary boundary fence and reprovision of boundary patrol road from Pak Hok Chau to Sha Tau Kok. 

2.3.3                                Dry Weather Flow Interception on Shenzhen Side

Currently, the separation of sewage from stormwater in Shenzhen is not very effective and stormwater discharge points at Shenzhen side into the Shenzhen River is polluted.  As part of this Project, the dry weather flow from these outflows will be collected and diverted to the Luo Fang Sewage Treatment Works in Shenzhen in order to improve the water quality of Shenzhen River.     

24 overflow manholes will be constructed to collect the dry weather flow and gravity sewer will be built to convey the dry weather flow to the Luo Fang Sewage Treatment Works. 

2.3.4                                Landscaping Works

The landscaping works along the riverbank will be designed to re-establish the natural riparian ecosystem with the aims to enhance the local biodiversity, protect the water resources and avoid erosion.  The landscape characters along the river course will be designed with considerations of local characteristics and the landuse planning in the adjacent area.  

2.4                                      Construction Programme

The construction phase of the main works will last for 44 months.  An Advanced Works contract on the construction of boundary fence and boundary patrol road on Hong Kong side will be included as part of this Project and will last for about 36 months between the period of February 2012 and January 2015.  The proposed construction programme is presented in Table 2.1.

Table 2.1        Construction Programme

 

Phase

Date

Duration

Works Description

1

Advanced Works

February 2012 to January 2015

36 months

Construction of boundary fence and boundary patrol road on HK side

2

Preparation Phase

March to July 2013

 

5 months

Tendering; land resumption

3

Pre-construction

August to September 2013

2 months

Construction of site access roads and site office, site clearance, site preparation works etc.

 

4                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     

Construction

October 2013 to December 2016

39 months

Main construction works of the Project such as dredging of river sediment and soil excavation, construction of flood retardation pond, boundary fence and boundary patrol road on Shenzhen side, river modification works, dry weather flow interception works etc.

 

5

Post-construction

January 2017 to March 2017

3 months

Demolition of temporary structures, landscaping works etc.

2.5                                      Maintenance Dredging

It is revealed in the sediment modelling result that the amount of sedimentation in the section of Shenzhen River within the Project Site is minimal, due to the fact that the gradient of the concerned river section is relatively steep and the river is not affected by tidal movement.  Hence, only small scale maintenance dredging activity along the river channel is anticipated at regular intervals (the frequency will be determined through sediment monitoring in the operation stage), and the scale of maintenance dredging will be very small as compared with the dredging works during the capital works construction.

Maintenance dredging of sediment may be required at the flood retardation pond on Shenzhen side and will be carried out by the Shenzhen side.  The flood retardation pond will only be used for water storage during severe rainstorm event in the wet season, and therefore the rate of sediment accumulation in the pond is expected to be small.  As such, and given that the size of the pond is only about 2.2 ha on plan, the scale and volume of the maintenance dredging, if required, is anticipated to be significantly smaller than that during the capital works construction. 


3                                            Summary of Environmental Impacts

3.1                                      Introduction

This Section summarises the environmental impacts associated with the construction and operation of the Project.

3.2                                      Air Quality

3.2.1                                Construction Phase

Construction dust generating from the soil excavation, embankment construction, dry weather flow interception works, landscaping works, patrol road and boundary fence re-provisioning and odour from dredging and handling of river sediment are the key air quality concerns during construction phase. 

With the implementation of the recommended dust control measures and good construction site practices, the construction of the Project will not cause adverse dust and air quality impacts at the identified air sensitive receivers (ASRs).  Dust monitoring during the construction stage is recommended to ensure compliance with the Air Quality Objectives.

The measured acid volatile sulphide (AVS) concentrations in the sediment samples of the Project Site were well below that for the remediated sediments, which are considered to have minimum odour impact to the surrounding environment.  The dredged sediment will be stored in enclosed tanks and will be delivered off-site for disposal at regular intervals.  Therefore, potential odour impact due to dredging and handling of river sediment will be minimal.

3.2.2                                Operation Phase

The frequency and scale of maintenance dredging required along the river channel and the flood retardation pond is anticipated to be very small compared with the dredging works during the capital works.  Besides, the dry weather flow interception works to be carried out under this Project will convey the untreated sewage from Shenzhen side (which are currently discharging to the Shenzhen River) to the sewage treatment work at Shenzhen.  It is therefore expected that the water and sediment quality of the Study Area will be improved after the completion of the Project.  The potential odour emissions due to the dredging and handling of sediment associated with maintenance activity will be minimal.  With the infrequent dredging activities required, limited quantity of sediments dredged and limited number of truck trips at Shenzhen side or marine vessels required, no adverse cumulative air quality impact is anticipated.

3.3                                      Construction Noise

Potential impacts to the noise sensitive receivers (NSRs) during the construction phase of the Project will mainly arise from the use of power mechnical equipment.  Owing to the close proximity of some of the NSRs to the works areas of the Project, mitigation measures are required to be implemented to mitigate the construction noise impacts.  Practicable mitigation measures, including good construction site practices, use of quiet PME, movable noise barriers and scheduling of PME/construction activities, are recommended.  With the implementation of mitigation measures, the mitigated construction noise levels at the representative NSRs will comply with the construction noise criterion of 75 dB(A) throughout the construction period.  Noise monitoring during the construction stage is recommended to ensure compliance with the noise criterion.

3.4                                      Water Quality

The potential sources of water quality impacts associated with the construction and operation of the Project have been identified and the potential impacts were evaluated using proven mathematical models.  The modelling has assessed a number of scenarios (including a number of worse case scenarios) for pollutants (including SS, heavy metal, nutrients and micro-organic pollutants) releases from the construction activities, and maintenance dredging and the change of the hydrodynamic conditions of the river during the operation of the Project.   

3.4.1                                Construction Phase

Potential impacts arising from the proposed construction works are predicted to be largely confined to the specific works areas.  With proper implementation of the recommended good site practices, sediment dispersion is not expected to cause adverse water quality impacts at the identified water sensitive receivers. 

3.4.2                                Operation Phase

During the operation phase, changes to hydrodynamic regime within the Project Site are predicted to be beneficial and no adverse impacts are anticipated.  Adverse water quality impacts are not expected at any identified water sensitive receivers due to the operation of the Project.  Within the Project Site, the scale and volume of the maintenance dredging activity will be significantly smaller than that of the capital construction work.  Adverse water quality impact is not expected.

Cumulative water quality impacts associated with operation of the LT/HYW BCP have been considered, no adverse impact is anticipated.

3.5                                      Terrestrial Ecology

The ecological resources recorded within the Study Area included twelve habitats (woodland [including fung shui woodland], plantation, shrubby grassland, low-lying grassland, marshy low-lying grassland, abandoned agricultural land, cultivated land (dry), wet active agricultural land, stream / river, channel, pond and developed area) of which only two were not found in the Project Site (shrubby grassland and pond).  Low-lying grassland, cultivated land (dry), wet active agricultural land, channel, pond and developed area (including road / path) were considered as having low ecological value, secondary woodland and the stream / river other than the Shenzhen River as having moderate ecological value, fung shui woodland as having high ecological value and the remainder (plantation, shrubby grassland, abandoned agricultural land, marshy low-lying grassland and Shenzhen River) as having low to moderate ecological value.  One small section of the Ping Yuen River, located within the Study Area but outside the Project Site, was considered of low to moderate ecological value, due to it acting as a possible breeding site for Greater Painted Snipe.  Overall 286 plant species were recorded in the Study Area, only one of which was a species of conservation interest (Incense Tree), which was recorded in the secondary woodland habitat to the south of the Tsung Yuen Ha within the Study Area.  No plant species of conservation interest was recorded within the Project Site.

A total of 38 wildlife species of conservation interest were recorded within the Study Area during the surveys, including six mammal species, twenty six bird species, two herpetofauna species, three butterfly species and one dragonfly species.  Only thirteen of these species were recorded in the Project Site during the surveys, twelve of them being highly mobile birds (Greater Coucal, Common Buzzard, Peregrine Falcon, Black Kite, Chinese Pond Heron, Black-crowned Night Heron, Grey Heron, Great Egret, Intermediate Egret, Little Egret, Common Teal and White-breasted Waterhen) and the other being the Courtesan butterfly which despite not being as mobile, has an abundance of similar habitat in the immediate vicinity.  Hence, it is anticipated that the impact to these species is low.

The Project will cause some permanent habitat loss.  The Shenzhen River will be disturbed during construction but additional stream/river habitat (> 2ha), woodland habitat (~0.5ha) and riverbank landscaping areas (>4 ha) will be formed after river modification works.  Given the relatively low value of the habitat and the low faunal abundance / diversity in the area, the impact of the Project is anticipated to be low.  With the implementation of the proposed mitigation measures and good construction practice no unacceptable ecological impact is anticipated.

3.6                                      Fisheries

A total of one active fishpond and three abandoned fishponds were identified within the 500 m Study Area of the Project Site.  No direct or indirect negative impacts on the pond fish culture resources are anticipated during the construction or operation of the Project.

3.7                                      Waste Management

3.7.1                                Construction Phase

During the construction phase, the main activities, which will result in the generation of waste, include dredging of river sediment, soil excavation, embankment construction, sewage diversion works, landscaping works, and patrol road and boundary fence re-provisioning.  The waste types associated with these activities include dredged river sediment, C&D materials, chemical waste, sewage and general refuse.

It is estimated that the gross total C&D materials generated from the Advanced Works will be about 18,750 m3.  About 15,000 m3 will be inert but are not suitable fore reuse on site.  These materials will be disposed of in a public fill reception facility in HKSAR.  A small quantity of about 3,750 m3 of construction waste (non-inert C&D material) will be disposed of at the NENT Landfill.

It is estimated that a gross total excavated materials generated from the river modification and associated works will be about 690,200m3, comprising 95,000 m3 of river sediment, 595,200 m3 of C&D material . For the 95,000 m3 river sediment, about 27,000 m3 with all contaminants levels not exceeding the LCEL (Category L) will be disposed of at Huangmao Dao in Zhuhai, and the remaining sediments (with Categories M and H) of 68,000 m3 will be disposed of at the Type 1 (dedicated) and Type 2 marine disposal facilities as appropriate within the HKSAR, to be determined by the MFC of the CEDD.  Of the 595,200 m3 C&D materials, about 586,000 m3 are inert in nature.  About 114,800 m3 of these inert C&D materials will be reused on site for backfilling or embankment construction and the surplus inert C&D materials of about 471,200 m3 will be disposed of at Huangmao Dao (黃茅島) in Zhuhai.  About 9,200 m3 of construction waste will be generated and disposed of at landfills in Shenzhen.

During the peak construction period (during the river modification and the associated works), approximately 878.5 kg per day of general refuse will be generated (195 kg from Advanced Works and 682.5 kg from River Modification and Associated Works).  General refuse will be disposed of at landfills in Shenzhen or at NENT Landfill in the HKSAR (for the Advanced Works).  Provided that the general refuse are properly collected and disposed of at regular intervals, no adverse environmental impacts are envisaged.

Chemical waste will be handled in accordance with the Code of Practice on the Packaging, Handling and Storage of Chemical Wastes.  For the Advanced Works, the chemical waste will be collected by a licensed chemical waste collector to the Chemical Waste Treatment Facility for disposal.  For the river modification and the associated works, the chemical waste will be collected and disposed of at licensed hazardous waste treatment facilities in Shenzhen.

With the implementation of general good construction site practices, it is not anticipated that the construction of the Project will cause adverse environmental impacts due to handling, transportation and disposal of the wastes.

3.7.2                                Operation Phase

Maintenance dredging will be carried out along the river channel and the flood retardation pond.  The scale of the dredging work is anticipated to be small and hence the volume of sediment is expected to be less than that of the dredging works during the construction phase.  The disposal and handling of the dredged materials will follow the requirement in the ETWB TC(W) No. 34/2002.

With the implementation of general good construction site practices, it is not anticipated that the operation of the Project will cause adverse environmental impacts due to handling, transportation and disposal of the wastes

3.8                                      Land Contamination

In the vicinity of the Project area, a few potential commercial and industrial developments were identified during the site surveys.  These included abandoned poultry/livestock farms, a plant nursery, a non-operating industrial facility (a bean curd stick production plant) with an air emission stack, a police station with a dangerous goods store, and a pumping station for the Ping Yuen River.  The potential land contamination risks of these facilities to the Project area were assessed and identified only one site required intrusive site investigation to confirm if the soil is contaminated.  Based on the soil analytical results, it is concluded that there is no significant contamination at the identified potential site of land contamination.  All results were below the respective Risk Based Remediation Goals (RBRGs) – Rural Residential for the parameters tested.  As no groundwater was present at the sampling depth of 3 m (bgs), groundwater samples were not retrieved.  There is no risk to humans from the handling of the excavated soil and therefore no further assessment or remediation of soil is required.

As the result of the above, no potential impact from the contaminated soil is anticipated.

3.9                                      Cultural Heritage Impact

Literature review and field surveys identified no Declared Monument and government historic sites within the CHIA Study Area of this Project.  Five graded historic buildings, one nil grade historic building, sixteen built structures, seven graves and four cultural/historical landscape features are identified within the CHIA Study Area and a small quantity of fragmented secondary archaeological deposits were identified from archaeological survey at Chuk Yuen and Pak Fu Shan sections of the Project.  Other sections have been identified with no archaeological potential where no impact is anticipated.  In case the works boundary of the Project changes during the detailed design stage to cover additional area not being assessed, the need for further archaeological survey and subsequent impact assessment should be reviewed and AMO should be consulted.

None of the identified built heritage features will be directly or indirectly impacted by the proposed development as they are located far from the Project Site.  No mitigation measure or monitoring will be required during the construction and operation phases of the Project.  

The archaeological survey identified only the secondary archaeological deposits at Chuk Yuen and Pak Fu Shan sections of the Project.  The chance of finding in situ archaeological deposits is very low.  Therefore, no impact on significant archaeological resources is anticipated and thus no archaeological monitoring is required.  Pursuant to the Antiquities and Monuments Ordinance, the project proponent should inform the AMO immediately in case of discovery of antiquities or supposed antiquities in the course of soil excavation works in construction stage.

3.10                                  Landscape and Visual Impact

With regard to LIA, a total of 18 LRs and four LCAs have been identified in the Study Area.  There will be moderate or slight residual landscape impacts on eight LCAs/LRs as detailed below.

The significance of residual, adverse landscape impacts on LCA 4 (Natural River and Floodplain Landscape), LR2 (Natural Watercourse) and LR8 (Shrubby Grassland on Lowland) is moderate.

The significance of residual, adverse landscape impacts on LCA 1 (Settled Agricultural Lowland Landscape), LR4 (Woodland on Hillside), LR5 (Woodland on Lowland), LR9 (Active Farmland) and LR10 (Inactive Farmland) is slight.

Upon mitigation, at day 1 of operation, the significance of residual, adverse impact on one LCA and two LRs is moderate (LCA4 (Natural River and Floodplain Landscape), LR2 (Natural Watercourse) and LR8 (Shrubby Grassland on Lowland)).  The significance of residual, adverse impact on five LCA/LRs is slight (LCA 1 (Settled Agricultural Lowland Landscape), LR4 (Woodland on Hillside), LR5 (Woodland on Lowland), LR9 (Active Farmland), LR10 (Inactive Farmland)).  The significance of residual impacts on the thirteen other LCAs/LRs is insignificant (LCA 2 (Natural Vegetated Hillside Landscape), LCA 3 (Channelised Watercourse Landscape), LR1 (Channelised Watercourse), LR3 (Pond), LR6 (Fung Shui Forest), LR7 (Shrubby Grassland on Hillside), LR11 (Commercial Farm), LR12 (Village Area), LR13 (Traditional Village Area), LR14 (Abandoned Village Area), LR15 (Temple), LR16 (Rural Built/Open Storage Area) and LR17 (Ongoing Development)) with the exception of the residual landscape impact on LR 18 (Roads) which is insignificant if not slightly beneficial.  At year 10 of operation, when planted and natural vegetation has had time to mature all residual impacts for these LRs are either slight or insignificant, and the residual impact on LR 18 (Roads) remains insignificant if not slightly beneficial.

The Project has insignificant residual landscape impacts on all other LCAs/LRs.

With regard to VIA, five VSRs representing two categories (residents and travellers) were identified in the visual envelope to represent key visually sensitive receivers in the area.  Photomontages were constructed at three VPs in three of these VSRs to help illustrate the visual impact of the Project.  A further two planned VSRs have been identified: the future residents of the re-sited Chuk Yuen Village and the future travellers through the LT/HYW BCP. 

At construction phase, the residual visual impacts after the implementation of mitigation measures moderate for three VSRs (residents of Ta Kwu Ling Village, Residents of Kaw Liu Village and Residents of the current Chuk Yuen Village) and slight for three VSRs (Travellers along Lin Ma Hang Road, Residents of Tsung Yuen Ha and future Residents of the re-sited Chuk Yuen Village).  Construction phase impacts are not applicable for one VSR (Travellers through the LT/HYW BCP), since it will not exist during this phase.

At operation phase, following the implementation of the proposed visual mitigation measures, at day 1 of operation, the mitigated impacts are slight for four VSRs (Residents of Ta Kwu Ling Village, Residents of Kaw Liu Village, Travellers along Lin Ma Hang Road and Residents of the current Chuk Yuen Village if the village is still in existence); and insignificant for two VSRs (Residents of Tsung Yuen Ha and future Residents of the re-sited Chuk Yuen Village).  The LT/HYW BCP will not be operational at this point, so the visual impact on Travellers through the LT/HYW BCP is not applicable.  At year 10 of operation, when planted and natural vegetation has had time to mature all residual impacts are insignificant, including for Travellers through the LT/HYW BCP which will be operational by this time.

According to Annex 10 of the EIAO-TM, the landscape and visual impact are considered acceptable with mitigation.

3.11                                  EM&A Requirement

Monitoring of dust, noise, and water quality has been recommended at designated sensitive receivers during the River Modification and Associated Works.  Environmental site audit shall be conducted throughout the construction phase for both River Modification Works and Associated Works and Advanced Works to ensure that the proposed mitigation measures are implemented, and completed landscape works will be monitored during a one-year establishment period. 

A bird monitoring programme will be undertaken to monitor the effectiveness of the reprovisioned/reinstated habitats during the operation of the Project.  Monitoring of bird abundance and occurrence will be undertaken for one year after the establishment of the landscape plantings of the Project.

3.12                                  Overall Conclusion

The environmental impact assessment has concluded that no unacceptable environmental impacts are envisaged as a result of the construction and operation of the Project, provided that the recommended mitigation measures are implemented.