EXECUTIVE SUMMARY

 

 

Planning of the Spur Line linking the existing KCRC East Rail at Sheung Shui with the proposed Shenzhen Metro system at Huanggang Station, opposite Lok Ma Chau, has taken place over a 10 year period. The new railway is needed to provide for the rapidly expanding demand for cross boundary passenger movement between the SAR and Shenzhen. The Spur Line proposal was presented in the Railway Development Strategy in May 1993.

 

In 1998, a Preliminary Project Feasibility Study (PPFS) evaluated the engineering and environmental feasibility of the potential routes linking the two rail systems. The PPFS considered at grade, tunnel and viaduct routes across the ecologically sensitive Long Valley. The horizontal rail alignment at Lok Ma Chau proposed in 1993 was amended to meet environmental constraints, doubling up with the existing transport corridor for the Lok Ma Chau Road crossing and minimising the impacts on the fishponds within the newly designated Wetland Conservation Area (WCA).

 

A full Environmental Impact Assessment (EIA) study was undertaken from May 1999 to June 2000 recognising the Spur Line as a designated project under the new EIA Ordinance. The EIA reviewed the development of a feasible rail alignment with environmental, engineering and railway design constraints being considered. These requirements defined the route across the ecologically sensitive area of Long Valley. The viaduct proved to be the most effective option for Long Valley and an ecological compensation scheme was devised to overcome the potential adverse construction and operational impacts. The EIA also identified and quantified all the other potential environmental impacts of the railway proposal and formulated suitable mitigation measures, where necessary.

 

The EIA was confirmed to have met the requirements of the Technical Memorandum of the EIAO and passed into the statutory public consultation phase. Subsequently as a consequence of the findings of the consultation process, which included issues of alternative alignments and uncertainties as to the potential for success of the ecological compensation measures, the Director of Environmental Protection (DEP), declined to approve the EIA report or award an Environmental Permit.

 

KCRC followed the Appeal provisions enshrined in the EIAO and the Appeal Board heard the case in April 2001.   The Appeal Board judgement in July 2001 upheld the DEP’s decisions not to approve the EIA report and not to issue an Environmental Permit.

 

However, the Appeal Board judgement recognised that it was Government policy to implement the Spur Line and concluded, that after all the evidence had been presented, only three options could be considered as being viable alternatives for the Spur Line:

 

·        The viaduct as proposed;

·        The bored tunnel on the same alignment; and

·        The Northern Link

  

The Appeal Board further noted that the Northern Link would require a major change in government policy rendering it outside any useful consideration for the Appeal. Two options thus remained.

 

In line with other recommendations made in the Appeal judgement, KCRC have had extensive consultations with AFCD and EPD on the way forward for the Spur Line project.  Uncertainties about the sufficiency of information to ensure an effective ecological compensation design and management strategy, and the time required to address these doubts, favours selection of a tunnel below Long Valley, rather than viaduct so as to avoid any ecological impacts.  The principal benefits of the tunnel option are the avoidance of adverse impacts on ecology, visual and landscape features, and the potential benefits to the planning opportunities within the proposed Kwu Tung North New Development Area (NDA).  Following publication of a new Project Profile in September 2001, a new EIAO Study Brief was published on 15th October 2001. The response to this new EIA Brief is the subject of this Report.

 

The environmental assessment of the tunnel option, as shown in Figure 1, includes: potential hydrological impacts within Long Valley, ecology (particularly at Lok Ma Chau), fisheries, air quality, construction and operational noise, water quality, waste, contaminated land, cultural heritage and landscape and visual impacts.  The western end of the Spur Line alignment, remains unchanged and continues to rise onto viaduct, and terminates at Lok Ma Chau Station Terminus within the Wetland Conservation Area (WCA).

 

 

Hydrology

 

One of the main concerns with regard to tunnelling under Long Valley is the potential for the tunnel to impact the groundwater regime.  Impacts could be through draw down or contamination of the groundwater.  During construction of the tunnel beneath Long Valley, potential impacts on the hydrological regime have been minimized through the use of an Earth Pressure Balance Tunnel Boring Machine (EPB TBM) which balances external pressures at the cutting face, and prevents ingress of groundwater.  Impacts on groundwater quality are minimized through the use of a foam to form a paste for spoil extraction.  The foam is non-toxic and readily biodegradable and therefore causes no adverse environmental impact. Groundwater levels and surface settlement will be intensively monitored as the TBM passes, and action and contingency plans have been prepared for implementation if necessary.

 

The vertical profile of the tunnel has been designed to be well below the main alluvial aquifer of the valley.  The permanent presence of the tunnel will therefore have minimal impact on the groundwater regime within Long Valley, as demonstrated through modelling of the current and future groundwater flows.  Monitoring of groundwater levels within Long Valley has shown that tidal influences are considerably greater than predicted impacts from the presence of the tunnel.

 

 

Ecology

 

The placement of the Spur Line in tunnel below Long Valley totally eliminates ecological impacts to this ecologically sensitive area and thus negates the need for compensation.  Potential disturbance during construction close to Long Valley will be minimized through measures defined for sensitive receivers close to the works.

 

The main ecological impacts arise from the above ground section of the railway mostly at the Lok Ma Chau Terminus.  Direct habitat loss due to the Terminus construction includes 7.0ha inactive fishponds that are utilized by large waterbirds and 0.4ha active fishponds from works associated with the viaduct. An additional 16.2 ha will be indirectly impacted due to disturbance to the most sensitive waterbirds that use the fishpond area around the future LMC Station and the area adjacent to the viaduct east of the Boundary Crossing.  These impacts of 23.6ha will be compensated for through the early enhancement of fishponds beyond the disturbance zone of the station works, followed by subsequent enhancement of an area of 27.1ha fishponds. . Early enhancement measures will include intensive repeat stocking of fish which will raise the carrying capacity of the stocked ponds for target species of large waterbirds (Black-faced Spoonbill, Great Cormorant, Great Egret and Grey Heron) above that required in the long term, thus compensating for the reduced area of disturbance-free habitat available. The proposed ecological mitigation measures are shown in Figure 2. Enhancement measures include re-profiling of pond bunds to create shallows where steep edges currently deter waterbirds from feeding; careful management of water levels to maximize feeding opportunities for target species; and stocking with a suitable size and type of fish. 

 

In addition, to reduce disturbance during operation of the railway, a marsh area will be created within 100m of the station building, and stands of bamboo and mixed trees and shrubs will be planted as a buffer around the station complex.  An additional 5 ha to the east of the station will be used as a reedbed for polishing effluent from the station sewage treatment works and provide additional areas of marsh and deep water for habitat diversity.

 

The ecological compensation proposed for the Spur Line project is unique in Hong Kong in its consideration of habitat loss and disturbance impacts, and provision for early compensation of construction impacts in the Lok Ma Chau fishponds area. This approach allows a mechanism for the long term protection and management of Hong Kong’s ecological resources.

 

 

Fisheries

 

Along the viaduct section of the alignment, several currently actively managed fishponds will be taken out of production during construction, and reinstated thereafter.  The small permanent loss of 0.4ha represents a minimal impact on fisheries production within the Study Area.  A temporary impact of less then 1.0ha to form a working area within 4 ponds beneath the viaduct represents a minimal impact.  The ponds will be reinstated after construction.  0.1ha of fishpond at Chau Tau will be impacted by the future railway maintenance yard. The 9.1ha of fishponds at Lok Ma Chau that will be impacted due to the station construction are currently inactive due to preparation of clearance-related procedures initiated by the government in November 2000.  The proposed ecological compensation scheme for impacts at Lok Ma Chau will involve fishpond management designed for wildlife.  KCRC will manage the site using traditional techniques to enhance the value of the area for waterbirds that currently utilize the area.

 

 

Air Quality

 

Potential impacts on air quality resulting from excavation of large volumes of waste material from the bored tunnelling will be minimized through regular removal of the relatively moist spoil. With the implementation of the recommended dust suppression measures and backed up by a properly designed EM&A programme, the construction of Spur Line is expected to comply with Air Quality Objectives.  Air quality impacts arising from the operational phase of the Spur Line are not of concern as limited potential emission sources have been identified.

 

 

Noise

 

Potential construction noise impact is predicted at most of the Representative Noise Sensitive Receivers along the Spur Line alignment. However, by a combination of direct technical measures, such as re-considering construction programme, reducing the number of construction equipment, using silenced models, and constructing site specific temporary noise barriers, no residual construction noise impact is expected.

 

Operational noise has been eliminated by placing the Spur Line in tunnel between Sheung Shui and Chau Tau.  The main source of noise at Sheung Shui is the turnouts required as the Spur Line diverges from the existing East Rail. Mitigation to achieve acceptable noise levels involves erection of absorptive cantilever type and absorptive vertical noise barriers adjacent to the turnouts.

 

Within the tunnel section, Low Vibration Track (LVT) will be used to minimize transmission of vibration to the surrounding ground.  Within the future Kwu Tung North New Development Area, Floating Slab Track (FST) will be used to allow for potential development above and alongside the proposed Kwu Tung Station and tunnels.

 

Several low rise sensitive receivers which are located close to the viaduct section of the Spur Line will experience unacceptable night-time noise levels in the absence of appropriate mitigation. Mitigation will include a reduction in train speed during the night time period, in additional to the standard measures of 1.2m parapet wall and Low Vibration Track.

 

 

Water Quality

 

Potential construction impacts on water quality during the construction phase include turbid, nutrient-rich run-off from excavation activities, increased pH and ammonia toxicity from concrete washings (particularly during diaphragm walling and the construction of the footbridge across Shenzhen River), chemical spillage and wastewater generation on site. A well designed and maintained site drainage system, correct handling and disposal of concrete washings and other wastewaters, appropriate control of chemicals, and provision of adequate facilities for site workers will minimize potential impacts during construction.

 

Potential impacts from moist spoil excavated from the tunnel will be minimized through the use of a treatment plant to reduce turbidity from discharge water. All watercourses in the area are within the Deep Bay Water Control Zone.

 

Potential operational impacts from the Spur Line railway involve hydraulic and pollution impacts from stormwater run-off from the railway tracks and the trains, hydraulic impacts from the footbridge across Shenzhen River, and pollution from sewage generated at Lok Ma Chau station.

 

The footbridge design has minimized impacts through appropriate design and location of piers.  Stormwater pollution will be minimized through the incorporation of appropriate pollution control measures such as oil interceptors/sediment traps into the drainage system design for the tunnel, viaduct and station, and regular maintenance of the system. To comply  with EPD’s Zero Discharge Policy (ZDP) requirement that the project should not cause a net increase in pollution load to Deep Bay, a reedbed around Lok Ma Chau Station will be used to polish sewage effluent and to treat a pollution load from the  adjacent river channel, equivalent to the residual pollution load discharged from the development.

 

 

Waste

 

A large quantity of construction and demolition materials (totalling approximately 1.2 million m3) will be produced during the construction of the Spur Line, about 90% arising from the bored tunnel and Kwu Tung Station Box excavation.  Most of this material will not be re-useable within the project due to programming constraints and must be disposed of to a designated public filling area.  A proportion of fill material required for Lok Ma Chau Station will be derived from suitable materials otherwise destined for public filling areas and will therefore ensure beneficial re-use as far as possible.  Other waste materials generated during the construction and operation of Spur Line will comprise excavated material, concrete, wood formwork, steel poles, chemical wastes, wheel wash wastes and general refuse. A waste management strategy is described, including methods for recycling or disposal, and responsibilities for implementation and management of the waste management procedure

 

 

Contaminated Land

 

Potentially contaminated land was identified at several locations along the alignment. A Contamination Assessment Plan (CAP) is proposed, which includes excavation of trial pits and boreholes followed by a sampling and analysis programme to determine the type and extent of contamination.  This will be undertaken immediately when possession of the land is granted.  Following the production of the Contamination Assessment Report (CAR), an evaluation of the mitigation measures to be used, including re-use on site, disposal or remediation will be prepared.

 

 

Cultural Heritage

 

Cultural heritage survey has determined that there are no historical buildings, which lie directly on the alignment. An archaeological survey within the study area has not found prehistoric sites that would be impacted. However, it is recommended that precautionary measures be included within the Works, with particular emphasis on the area to the south of Ho Sheung Heung where Sung material was found during survey and the area to be excavated for Kwu Tung Station Box.  Pre-construction testing, in the form of a programme of auger hole testing and test pit excavations, should be undertaken to clarify the status of the areas, and a watching brief should be implemented during excavation. Mitigation in the form of specification of working practices and screening of visual effects is recommended to the historical buildings which face emergency access structures associated with the Spur Line, such as Ho Sheung Heung village which contains notable cultural heritage resources.

 

 

Landscape and Visual Character

 

The proposed use of the tunnel for the eastern section of the Spur Line between Sheung Shui and Chau Tau in tunnel will to a large extent alleviate many of the landscape and visual impacts predicted for the original scheme proposals in this area. However there will be adverse residual landscape and visual impacts associated with the above ground structures for the tunnel, and the western viaduct section and Lok Ma Chau Terminus.  The proposed viaduct section and above ground structures will impact small areas of agricultural land, fishponds and plantation. However on the whole the Spur Line would not have a significant effect on the landscape resources with the loss of some 1,800 trees within the project limit and a further 250 trees to be transplanted. This would leave approximately 1,150 trees retained in situ. The proposed viaduct and terminus will also lead to adverse visual impacts, however a combination of the degraded nature of the existing visual amenity and the implementation of the proposed mitigation measures will largely alleviate these impacts.

 

The proposed mitigation measures include compensatory and screen planting with woodland areas adjacent to the viaduct columns and the above ground structures (approximately 4 hectares in total). The mitigation also includes the restoration of landscapes disturbed during the construction phase such as the reinstatement of fishpond areas below the viaduct section. In addition to this the visual appearance of the above ground and major engineering structures would be designed to minimise, as far as possible, the landscape and visual impacts. This includes for example the use of muted colours for the facades of the EAP and Ventilation Building, and the design of a visually ‘light’ and graceful, curving alignment for the viaduct section. The above ground structures in the central section of the proposed alignment will be located within the urban milieu of the future Kwu Tung North NDA and so be in context. The proposed noise barrier north of Sheung Shui Station has been designed to blend into the existing urban context of high-rise residential development and commercial premises.

 

The Lok Ma Chau Terminus has been designed with an organic form in terms of its roof line which will be responsive to the existing landscape and this will be further enhanced through the use of tree planting along the periphery of the station footprint. The structure will also be viewed against the high-rise urban backdrop and will not be a major source of impact. 

 

Overall the proposed Lok Ma Chau Spur Line proposals would in terms of residual landscape and visual impacts be ‘acceptable with mitigation’.  

  

 

Construction Technology

 

Details of the construction programme, the construction methodologies and an assessment of the extent to which the technologies to be employed are proven technologies are presented. The construction of the Spur Line has been broken down into 12 major elements for permanent works and 3 elements for temporary works.

 

The component methods for each of the elements, their programme duration and a commentary on previous use of such methods are listed. The methods have been chosen with a view to overcoming the constraints imposed by ground conditions and spatial constraints.  All proposed methods have been successfully used in railway construction in Hong Kong, or have been demonstrated to be successful in the Spur Line area.   For example the techniques used for the construction of the Lok Ma Chau Boundary crossing. In other respects standard construction techniques will be employed.

 

 

Land Use

 

The tunnel alignment of the Spur Line opens up the possibility of re-planning the central area of the Kwu Tung North NDA. Significant planning benefits can be gained depending on the approach taken. Assuming that the main distributor road in Kwu Tung North NDA is retained, benefits of the tunnel alignment include:

 

·        Enhanced open space provision;

·        Enhanced town centre amenity;

·        Greater pedestrian connectivity; and

·        More freedom in urban design.

 

The replacement of the previously proposed cutting, at grade and viaduct portions of the Spur Line railway throughout the NDA, offers new and advantageous opportunities in the overall planning of the Kwu Tung North area.

 

 

Environmental Monitoring and Audit

 

Environmental monitoring and audit requirements for the construction phase are described in terms of the monitoring locations, periods of time, frequency and standards against which the monitoring results should be compared to determine compliance. Operational monitoring will be required for the wetland compensation area to determine the success of establishment.  An Implementation Schedule for the works is included in Chapter 15 of the EIA report.

 

Conclusion

 

The conclusion of the EIA is that no insurmountable environmental impacts will result from implementation of the Spur Line project.

 


 

摘要

 

政府就九廣東鐵從上水伸延至落馬洲對岸皇崗地鐵站的規劃,歷時超過10年。由於香港與深圳的跨境客運需求不斷上升,這條新的支線急需興建。在1993年5月,支線的建議首先在《鐵路發展策略》中提出。

1998年,支線的可行性研究報告從工程及環保兩方面探討了連接九鐵及深圳市地鐵兩個系統的可行路線。可行性研究報告考慮了從地面、隧道及高架橋的方式穿過生態敏感度高的塱原,並對1993年提出的水平定線在落馬洲一段作出修改。修改的目的是克服環境的限制、配合落馬洲陸路過境通道及把對位於濕地保育區內的魚塘的影響減至最低。

按《環境影響評估條例》的規定,支線屬於指定工程項目。九鐵於1999年5月至2000年6月對支線進行全面的環境影響評估報告(下稱「環評報告」)。環評報告闡述了在制定可行路線的過程中所考慮的環境、工程及鐵路設計上的限制。這些因素決定了支線須經過生態敏感度高的塱原,而高架橋則被認為是最理想的方案。為紓緩工程在施工及營運期間的生態影響,九鐵制定了生態補償計劃。除此之外,環評報告鑑別及量化了所有工程對環境的潛在影響,並制定必要而合適的緩解措施。

經環境保護署(環保署)確定上述環評報告符合《環境影響評估條例》的技術備忘錄的要求後,隨即就環評報告進行了法定的公眾諮詢。諮詢結果顯示公眾對其他可行路線及成功實行生態補償計劃內容的不確定因素表示關注。因此,環保署長拒絕批准環評報告及發出環境許可証。

九鐵根據《環境影響評估條例》有關條文對環保署長的決定提出上訴。上訴委員會的聆訊於2001年4月開始,於2001年7月作出裁決,維持環保署長不批准環評報告及不發環境許可証的決定。

然而,上訴委員會確認興建支線是政府的政策,並認為在考慮所有呈堂証據後,支線的可行方案只有三個:

Ÿ             原來的高架橋建議

Ÿ             在原路線鑽挖隧道

Ÿ             興建北環線

 

上訴委員會進一步認為興建北環線牽涉政府政策的重大改變,不在上訴考慮之列。於是,剩下來的只有兩個方案。

在考慮上訴委員會判決的建議同時,九鐵就支線的未來發展廣泛徵詢了漁農自然護理署及環保署的意見。如採用原來的高架橋方案,由於未能知悉需搜集多少資料才可確保生態補償計劃的設計及管理策略有效,而且消弭上述疑慮需時較長,因此九鐵決定在塱原地底興建隧道,以避免生態影響。隧道方案的主要優點包括避免生態、視覺及景觀影響,並有利於擬建的古洞北新發展區的規劃。九鐵於2001年9月向環保署提交新的工程項目簡介,環保署於10月15日根據《環境影響評估條例》發出新的研究概要。本報告乃根據研究概要的要求而寫成。

對此隧道方案(見圖一)的環境評估包括:對塱原的潛在水文影響、生態影響(尤其在落馬洲)、漁業、空氣質素、施工及運作噪音、水質、廢物、受污染土地、文化遺產、景觀和視覺影響。定線西端仍維持原方案的工程設計,鐵路會從隧道上升至高架橋,並以座落於濕地保育區內的落馬洲總站為終點站。

水文影響

公眾對在塱原地底興建隧道的關注之一是會否對地下水構成影響,包括流失或污染地下水源。興建隧道期間,潛在的水文影響可通過使用「土壓平衡鑽挖機」而減至最低。土壓平衡鑽挖機可平衡鑽挖面的外在壓力,並防止地下水滲入。除此之外,在抽出棄土工序中只會使用泡沫藥劑,在形成黏貼層後抽出棄土。該泡沫劑無毒而易生化降解,因此不會引起惡劣的環境影響。在鑽挖機穿越塱原地底時,承建商會嚴密監察地下水的水位及地表的沉降。有需要時,承建商會執行既定的行動及應變計劃。

工程設計已將隧道置於遠離塱原主要的沖積土蓄水層以下的深度。現在及未來地下水流的模型分析顯示隧道的永久存在對塱原的地下水系統影響甚微。實際上,塱原地下水水位的監測結果顯示,潮汐對地下水位的影響,遠比隧道的影響為大。

生態影響

以隧道形式於塱原地下興建支線,完全消除了對這片生態敏感地區的生態影響而毋須進行生態補償。為施工範圍附近敏感受體而設的緩解措施,亦同時將施工期間對塱原的潛在滋擾減至最低。

工程主要的生態影響大多來自落馬洲總站附近的一段地面鐵路。興建總站造成的直接生境損失包括高架橋佔用7公頃大型水禽所使用的荒棄魚塘和0.4公頃營運中的魚塘;另外,未來落馬洲站和邊境管制站東部高架橋附近的16.2公頃魚塘區,會因大多數使用該區的敏感水禽受到滋擾而間接地受到影響。受影響的23.6公頃的補償措施包括:提早提高建站工程滋擾區以外的魚塘的生態價值,然後提高其餘27.1公頃魚塘的生態價值。報告建議的生態緩解措施載於圖二。提高生態價值的措施包括:在陡直的魚塘邊緣改造塘壆、增加淺水地帶以方便水禽覓食、細心管理魚塘水位以增加目標雀鳥品種的覓食機會,及養殖適當大小及種類的塘魚。

另外,為減低鐵路營運時的滋擾,在落馬洲車站大樓的100米內會闢設沼澤區,並在車站周圍種植竹樹、其他樹木及灌木作為緩衝區。在車站以東另外的5公頃土地會闢作蘆葦叢,以進一步淨化從車站污水處理廠排放出來的廢水。這可增加沼澤區及深水地帶之面積,從而增加生境的多樣性。

本工程建議的生態補償計劃獨特之處,在於考慮了生境損失和生態滋擾的影響,以及工程對落馬洲魚塘區的生態影響提供了早期的補償。這個做法為長期保護及管理香港的生態資源提供了一個可行的機制。

漁業影響

沿線的高架橋段有若干營運中的養殖魚塘將在施工期間停產,但會在施工後復原。在研究範圍內0.4公頃魚塘的小量的永久損失對漁業生產的影響微乎其微。用作施工區的高架橋下4個魚塘範圍內小於1公頃的暫時性影響亦極之微小,這些魚塘將於竣工後復原。位於洲頭的0.1公頃魚塘將受到未來鐵道維修場的影響。將受建站影響的位於落馬洲的9.1公頃魚塘由於政府2000年11月的清拆準備工作關係,現已停產。建議中的為落馬洲的影響所作的生態補償將包括為野生動物設計的魚塘管理計劃。九鐵將沿用傳統養殖技術以提高該區對使用魚塘的水禽的生態價值。

空氣質素

鑽挖隧道期間將挖出大量棄土,由於該等物料比較濕潤,可通過定期移走物料而將對空氣質素的影響減至最低。祇要執行建議的抑制揚塵的措施並輔以適當設計的環境監察計劃,落馬洲支線的興建預期能夠符合空氣質素標準。鐵路營運期間,由於已鑑定的排放源極少,故此對空氣質素的影響甚微。

噪音

預期在施工期間,支線沿線的大部分具代表性的噪音敏感受體將受到噪音影響。然而,通過結合各種直接技術措施,包括改動施工時間表、減少機械的數量、使用較寧靜的機械及在工地豎立臨時隔音屏,預計可消除剩餘的噪音影響。

支線在上水至洲頭一段將為隧道,完全消除了列車行駛的噪音。在營運期間主要的噪音來自上水一段,即支線從現時東鐵分岔的部分。

可行的緩解措施包括在分岔口旁豎立吸收性懸臂式及吸收性垂直隔音屏障。

隧道內將鋪設低振動軌道,使列車行駛時產生的震盪減至最少。鐵路穿越未來古洞北新發展區的路段將鋪設浮板軌道減低噪音,使日後古洞站及隧道的旁邊及上蓋仍可加以發展。

在未作任何緩解措施前,貼近高架橋路段的若干低層敏感受體在晚間承受的噪音,將達至不可接受的水平。除了標準1.2米攔墻和低振軌道以外,建議的緩解措施將包括列車在晚間減速。

水質影響

施工期間對水質的潛在影響包括:挖掘工程產生混濁及高養分的徑流、沖洗混凝土廢水引致酸鹼度及游離氨毒性的上升(尤其在建造膜壁及深圳河行人天橋時)、化學品泄漏及工地上產生的廢水。建議的緩解措施包括:設計良好及保養妥善的工地排水系統、正確處理及棄置沖洗混凝土廢水及其他廢水、適當控制化學品的使用、及為工人提供足夠的衛生設施。這些措施將可把潛在的影響降至最低。

從隧道挖出的濕潤泥土或會對水質產生影響。隧道鑽挖工程排出的水可通過處理設施減低其混濁度。由於研究範圍內的所有河流均位於后海灣水質管制區以內。

支線運行時的影響包括來自路軌及列車的雨水徑流所帶來的水流影響及污染、行人橋對深圳河的水流影響及落馬洲總站產生的生活污水。

緩解措施方面,行人橋墩的設計及位置已考慮了對深圳河水流影響的因素。雨水徑流的影響可通過在隧道、高架橋及車站的排水系統加裝隔油設施及沉澱器而減至最低。為符合環保署有關后海灣排放物的「零排放政策」,經污水處理廠處理的污水將引入落馬洲車站周圍的蘆葦叢以進一步淨化,並且於鄰近河道抽取相當於發展支線所排放的剩餘污染的污染量加以處理。

廢物

施工期間將產生大約120萬立方米的拆建物料,其中指定大約90%來自鑽挖隧道及古洞站的挖掘工作。當中大部分物料由於工程的局限而不能再用於本工程而須送往指定的公眾填土區。建造落馬洲站所需的部分填料將取自其他工程項目產生的適用物料,以確保這些本應送往公眾填土區的物料得以物盡其用。因支線施工及運行產生的其他廢物包括挖掘物料、混凝土、木板、鋼管、化學廢料、車輪清洗廢料及一般廢物。建議的廢物管理策略包括回收或棄置的方法及執行廢物管理的責任問題。

受污染土地

評估鑑別了鐵路沿線若干潛在受污染土地的位置。報告已就這些地點提出污染評估計劃,包括在這些位置開鑿探井及試坑取樣分析,以決定土地受污染的種類和程度。當收地工作完成後,取樣分析工作會立刻進行。在受污染土地評估報告完成後,將就著評估結果對緩解措施(包括工地上再用、棄置或整治有關物料)作檢討。

文化遺產評估

對文化遺產的評估結果顯示支線上並沒有歷史建築物。在研究範圍內,沒有任何史前遺址受本工程影響。但報告建議施工時採取預防措施,尤其應留意河上鄉以南發現的宋代文物及古洞站的範圍。在上述兩地施工前應進行一系列包括鑽孔及探坑的調查,在挖掘進行期間亦應作密切監察。面向支線緊急通道結構的歷史建築(如河上鄉村)有著豐富的文化遺產資源,建議的緩解措施為列明有關保護文物的施工守則,並遮擋工程的視覺影響。

景觀和視覺影響

支線東段(從上水至洲頭)以隧道形式建造大大紓緩了原計劃(高架橋方案)對景觀和視覺的影響。但是,隧道路段之上的建築物、西段高架橋及落馬洲總站會構成剩餘的景觀及視覺影響。

擬建的高架橋及地面設施會影響小範圍的農地、魚塘及植林。整體而言,工程並不會構成明顯的景觀影響。

總計本工程將損失1,800棵樹木及移稙250棵樹木,另外有1,150棵樹木將在原位保留。建議的緩解措施包括在高架橋支柱及地面建築旁種植補償性及遮蔽性樹木,合共約4公頃。

擬建的高架橋及落馬洲總站會引致不良的視覺影響。然而,現有視覺環境的質素正在下降,在實施建議的緩解措施後,將可紓緩這些影響。除此之外,緩解措施還包括恢復施工時受影響的景觀,包括修復高架橋下的魚塘。所有地面及主要工程建築的外形設計將盡量減少對視覺及景觀影響。這包括在緊急進入點及通風大廈的外牆採用柔和的顏色及高架橋採用視覺上較「輕鬆」的設計。支線中段的地面建築將位於未來古洞北新發展區內,故能與周圍都市環境融合。上水站以北的隔音屏障的設計將融入現有高層商住大廈的環境。

落馬洲車站的屋頂設計能配合現有景觀,在車站外圍植樹則可進一步美化環境。車站的背景為深圳的高樓大廈,故不會構成視覺影響。

總括而言,擬建落馬洲支線在實行緩解措施後,剩餘的景觀及視覺影響是可以接受的。

施工技術

本報告詳列了工程的施工時間表及施工方法,並且對擬用技術是否實際可行作出評估。整條支線的建造被細分為12個永久工程項目及3個臨時工程項目。

每個項目施工方法、施工時間表及有關方法的經驗分析已於本報告列明。選取的施工方法以盡量克服地質條件及空間限制為原則。所有施工方法已成功地在香港的鐵路建造工程或支線範圍內的其他工程採用,例如落馬洲邊境管制站工程。支線其餘工程將使用標準的技術施工。

土地用途

支線的隧道方案令未來古洞北新發展區中心地帶可以重新規劃。視乎區內主幹道的位置是否改變,重新規劃將可帶來顯著效益。假定古洞北新發展區的主幹道的位置不變,隧道方案的好處包括: 

Ÿ             增加休憩用地

Ÿ             增加市中心康樂設施

Ÿ             改善行人道之間的連繫及

Ÿ             使新市鎮設計有更大的自由度

 

將支線途經古洞北新發展區的一段從原建議的削土、地面及高架橋形式改為隧道,可為古洞北的整體規劃帶來新的機會。

環境監測與審核

環境影響評估報告闡述了施工期間的環境監測與審核要求,包括監測地點、時間、頻率及標準。監測的結果將與這些標準作比較,以斷定工程是否符合要求。濕地補償地帶設立後,須就其運作進行監測,以了解其成效。本評估報告第15章已包括有關工程的緩解措施執行計劃表。

結論

總括而言,評估結果顯示上水至落馬洲支線工程將不會構成不能克服的環境影響。

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