1.0 INTRODUCTION

1.1 The Consultancy

Ove Arup & Partners Hong Kong Ltd (Arup) was commissioned by the Drainage Services Department (DSD) of the Government of the Hong Kong Special Administrative Region to provide consultancy services in respect of the environmental and traffic impacts arising from the Stage 2 of PWP Item No. 215DS - Yuen Long and Kam Tin Sewerage and Sewage Disposal (YLKTSSD) under Agreement No CE 66/2001(EP), on 30 April 2002 for a study period of about 18 months.

1.2 The Project Background

The design and construction supervision of the Project are/will be undertaken by the in-house staff of DSD. The Chief Engineer/Sewerage Projects, DSD, is responsible for the civil engineering works while the Chief Engineer/Electrical and Mechanical Projects, DSD, is responsible for the electrical and mechanical works.

The Project is part of the “Yuen Long and Kam Tin Sewerage and Sewage Disposal” (YLKTSSD) scheme as recommended in the “Review of Yuen Long and Kam Tin Sewerage and Sewage Treatment Requirements” study (completed in January 1999). The YLKTSSD scheme is aimed at phased implementation of sewerage extension in the Northwest New Territories to cope with the existing and planned developments. This Stage 2 Project involves the following key items of works: -

· to provide a pumping system for conveying treated effluent from Yuen Long Sewage Treatment Works (YLSTW) to San Wai Sewage Treatment Works (SWSTW);

· to provide a trunk sewerage system consisting of gravity sewers, rising mains and pumping stations for San Tin areas, for conveying sewage to the YLSTW via another downstream trunk sewerage system;

· to provide a trunk sewerage system consisting of gravity sewers, rising mains and pumping stations for conveying sewage generated from Lau Fau Shan areas, to SWSTW; and

· to provide a trunk sewerage system consisting of gravity sewers, rising mains and pumping stations for Yuen Long South areas for collection and conveyance of sewage generated from the areas to SWSTW via another trunk sewerage system and the existing Ha Tsuen Pumping Station.

1.3 The Site Location and Works

The general overview of the sewerage system in the North NT is illustrated in Figure 1.0. The Project is divided into several works packages (Figure 1.0a). Each works package comprises several works items which are detailed in Table 1.1 and Figures 1.1 to 1.4. The overall study area and the interfacing boundary are shown in Figures 1.5 to 1.8. The whole extent of the sewerage system is about 28km, and careful consideration has been made such that the majority part of the sewer will be laid underneath existing or future roads (upto 83% of the sewer). This can significantly reduce the overall disturbance and environmental impact to the residents.

Table 1.1:Details of works packages

Works Package	Works Item	Location
Works Packages and Works Items for Stage 2 Works
Tin Shui Wai and San Wai Areas
2A-1T	OP1	Pumping station in the north of YLSTW (Yuen Long Effluent Pumping Station) where treated effluent will be handled
	OS1	Twin rising mains from item OP1 to Tin Tsz Road in Tin Shui Wai
	OS2	Twin rising mains from Tin Tsz Road via Tin Wah Road to Tin Ying Road in Tin Shui Wai
	OS3	Twin rising mains along Tin Ying Road in Tin Shui Wai
	OS4	Twin rising mains from Tin Ying Road to Ping Ha Road
	OS5	Twin rising mains from Ping Ha Road via Tin Ha Road to SWSTW
Tin Shui Wai and San Wai Areas
Alternative scheme of 2A-1T	AP1	Pumping station in the north of YLSTW (Yuen Long Effluent Pumping Station) where treated effluent will be handled
	AS1	Twin rising mains in the northwestern side of YLSTW
	AS2	Twin rising mains from item AS1 to Fuk Shun Street
	AS3	Twin rising mains from Fuk Shun Street to Tin Wah Road in Tin Shui Wai
	AS4	Twin rising mains between Tin Wah Road and Tin Ying Road in Tin Shui Wai
	AS5	Twin rising mains from item AS4 to Ping Ha Road
	AS6	Twin rising mains from Ping Ha Road to SWSTW
Ngau Tam Mei and San Tin Areas
2A-2T	P1	Ngau Tam Mei sewage pumping station
and	S1	Sewers along Ngau Tam Mei Main Drainage Channel Phase 1 from P1 to Nam San Wai sewage pumping station (SPS)
2B-1T	S2	Branch sewers from Fairview Park to S4 along Ngau Tam Mei Main Drainage Channel Phase 1 opposite to S1
	P2	Tam Mei Barracks SPS (Tam Mei Camp SPS)
	S3	Branch sewers from P2 to P1 along Main Drainage Channel for Ngau Tam Mei Phase 2
	S4	Sewers from P3 to P1 along Castle Peak Road-San Tin near Yau Mei San Tsuen, Mai Po San Tsuen and Mai Po Lo Wai
	P3	San Tin SPS
	S5	Sewer upstream of P3 near Tsing Lung Tsuen
	P4	San Lung Tsuen SPS
	S6	Branch sewers from P4 to S5 along the village tracks in Fan Tin Tsuen
	P5	San Tin Barracks sewage pumping station (Cassino Line SPS)
	S7	Sewer from P5 to S5
Lau Fau Shan and Mong Tseng Areas
2A-3T	A1	Lau Fau Shan SPS
	G1	Sewers from A1 to Tin Shui Wai Reserved Zone pumping station (TSWRZPS)
	A2	Mong Tseng SPS
	G2	Sewers along Lau Fau Shan Road from A2 to TSWRZPS
Shap Pat Heung Area
2B-2T	B1	Shan Ha Tsuen SPS
	H1	Sewers from B1 to the connection sewer at Yuen Long Highway
	B2	Muk Kiu Tau Tsuen SPS
	H2	Sewers along Kung Um Road from B2 to the connection sewer at Yuen Long Highway
	B3	Sham Chung Tsuen SPS
	H3	Sewers from B3 to the connection sewer at Yuen Long Highway
	B4	Shui Tsiu San Tsuen SPS
	H4	Sewers from B4 to B3
	H5	Sewers from Tai Tong Tsuen to B4
	B5	Shung Ching San Tsuen SPS
	H6	Sewers along Tai Tong Road from Hung Tso Tin Tsuen to B5
	H7	Sewers from B5 to the connection sewer at Yuen Long Highway
	B6	Nga Yiu Tau SPS
	H8	Sewers along Tai Shu Ha Road East from Tong Tau Po Tsuen to B6
	H9	Sewers along Tai Shu Ha Road East from B6 to the connection sewer at Yuen Long Highway
	B7	Pak Sha Tsuen SPS
	H10	Sewers along Kung Um Road from Wong Nai Tun Tsuen to B7
	H11	Sewers from B7 to B2

Legend:		- Designated Elements

		- Non-Designated Elements

1.4 Previous Studies

A Preliminary Project Feasibility Study has been completed in January 1998 and an Adoptive Review on Package 2A-1T (Yuen Long Effluent Pipeline) was circulated for departmental comments on 25 September 2001. The capacities of some pumping stations have been upgraded to cater for future detailed design.

According to the latest design information provided by DSD dated Feberary 2004, the following works items are classified as Designated Elements:

· OP1 (Treated effluent pumping station in the north of YLSTW – 2A-1T Conforming Scheme) by virtue of Item Q.1 of Schedule 2, Part I under the EIAO

· OS1 (Twin rising mains from item OP1 to Tin Tsz Road in Tin Shui Wai – 2A-1T Conforming Scheme) by virtue of Item Q.1 of Schedule 2, Part I under EIAO

· AP1 (Treated effluent pumping station in the north of YLSTW – 2A-1T Alternative Scheme) by virtue of Item Q.1 of Schedule 2, Part I under the EIAO

· AS1 (Twin rising mains in the northwestern side of YLSTW – 2A-1T Alternative Scheme) by virtue of Item Q.1 of Schedule 2, Part I under EIAO

· P1 (Ngau Tam Mei sewage pumping station – 2A-2T and 2B-1T) by virtue of F.3(b) of Schedule 2, Part I under the EIAO

In the previous Adoptive Review, reports had been circulated to various departments. It indicated that the 2A-1T conforming scheme was a “No-built” option; especially with significant impact on the Deep Bay Buffer Zone. A more detailed comparison is listed in Section 2.

1.5 Environmental Needs and Benefits

A Yuen Long and Kam Tin Sewerage Masterplan Study (SMP) was conducted in 1992 to address the overall demand in sewerage system in the region. It was recommended that a regional sewerage network, for the existing unsewered villages and new developments, was required in the NWNT and all sewage flows within the planned catchment area shall be collected and then discharged via Urmston Road outfall. This plan can contribute substantially to the aim of zero discharge to Deep Bay. Subsequently, a supplementary PPFS Report to PWP Item 4215DS admitted in 1998 RAE. With the incorporation of the latest planned development of the area, based on the best available information development projections in mid-1998. The report concluded that the need for an overall sewage transfer strategy was verified and found valid. The report reviewed that the pipe sizes and capacities of pumping stations shall be revised to reflect the latest population demand. In accordance with the recommendation in the supplementary PPFS, option/site selection had been conducted by DSD and subsequently a preliminary design of the sewerage system is being carried out. An Environmental Impact Assessment for PWP item 215DS is therefore conducted to identify any potential environmental impact.

It is anticipated that by the completion of this Project, all untreated village sewage/new development flows within the planned catchment will be treated and then diverted away from Yuen Long Sewage Treatment Works to Urmston Road outfall so as to achieve the long-term ultimate aim of zero discharge to Deep Bay. The wild life within the Deep Bay Water Control Zone and Deep Bay Buffer Area will be benefited. The proposed system has been planned for a total population of about 900,000 people.

1.6 Structure of the Environmental Impact Assessment (EIA) Report

The structure of this EIA report is outlined below for easy reference:

Table 1.2: Report structure

Section	Title	Aims
1	Introduction	An introduction of the background information and the layout of the EIA report
2	Project Description	A description of the extent and details of the proposed project
3	Study Objectives and Scope	Outline the objectives and scope for various environmental aspects
4	Available Technical Information	List the key information reviewed in this EIA study
5	Alignment Options Consideration	Describes the options considered and presents the associated benefits and disbenefits
6	Dust Impact Assessment	Present the legislation, methodology and recommendations for air quality impacts during construction phase
7	Odour Impact Assessment	Present the legislation, methodology and recommendations for odour impacts during operational phase
8	Construction Noise Assessment	Present the legislation, methodology and recommendations for the construction phase
9	Operational Noise Assessment	Present the legislation, methodology and recommendations for the operational noise impacts from pumping stations
10	Water Quality Assessment	Present the legislation, methodology and recommendations for water quality impacts
11	Waste Management	Present the legislation, methodology and recommendations for waste management
12	Land Contamination Implications	Present the legislation, methodology and recommendations for potential land contamination implication
13	Ecological Assessment	Present the legislation, methodology, survey findings and recommendations for ecological impact
14	Landscape and Visual Impacts	Present the legislation, methodology and recommendations for landscape and visual impacts
15	Cultural Heritage Assessment	Present the legislation, methodology, survey findings and recommendations for cultural heritage
16	Fishery Assessment	Present the legislation, methodology, survey findings and recommendations for fishery impact
17	Environmental Monitoring and Auditing Programme	Present the legislation, methodology and recommendations for EM&A
18	Summary of Envionmental Outcomes	Summary of the findings and recommendations
19	Conclusion	Concluding the study
20	References	List of relevant reference

2.0 PROJECT DESCRIPTION

2.1 Construction Phasing and Details in North West New Territories

The Project involves the phasing development of sewerage in the North West New Territories to match the planned development of this area. The sewerage development is divided into four principal areas: Kam Tin; Ngau Tam Mei and San Tin; Lau Fau Shan; and Yuen Long South. The first priority will be the construction of a trunk sewer to transfer sewage from Kam Tin Core Area to Yuen Long Sewage Treatment Works, which are being designed in the Stage 1 of YLKTSSD. The sewage generated from Yuen Long Town, Areas 13 & 14, Tin Shui Wai Reserve Zone and Au Tau is collected and discharged to Ha Tsuen Sewage Pumping Station and then to San Wai STW eventually. As such, expansions of San Wai STW and Ha Tsuen Sewage Pumping Station under PWP Item No. 4215DS Stage 1 Package 1A-2T are required to accommodate such sewage flows. The remaining packages under PWP Item No. 4215DS Stage 1 are 1A-1T - Kam Tin Trunk Sewerage Phase 1 and 1B-1T - Kam Tin Sewerage Phase 2. The EIA report of Stage 1 YLKTSSD was approved on 26 Aug 2002, and the tentative construction programme was scheduled between Aug 2003 to Nov 2006. Nonetheless, the actual programme for each individual package will be determined at the detailed design stage, while the total flow could reach the Stage 1 capacities by 2006.

The expansions of the San Wai STW and Ha Tsuen Pumping station are required to accommodate such flows and to ensure that these facilities will not constrain medium term development planning. A separate EIA study report has therefore been submitted and approved by EPD on 12 May 2003. The construction of the sewerage works under the Package 1A-2T - Expansion of San Wai STW and Ha Tsuen PS and Package 1A-1T – Kam Tin Trunk Sewerage Phase 1 were tentatively scheduled between June 2006 to January 2010 and June 2005 to December 2007 respectively. The actual implementation programmes and works details of the projects are being under review and yet to be finalised. The current status of the San Wai STW is classified as "Cat. B under Planning".

The initial phases of the trunk sewers for Ngau Tam Mei and the rest of Kam Tin will follow closely behind to provide the possibility of connection of impending development and also existing development which is served by small treatment plants which can then be decommissioned. However, prior to the connection of sewerage from Fairview Park, Tam Mei Camp and other parts of the Ngau Tam Mei catchment, a major pumping station at Yuen Long STW and a new rising main to transfer flows from the treatment plant to SWSTW should be constructed.

The second stage also includes connections from Lau Fau Shan/Mong Tseng and San Tin areas followed by branch sewers at Yuen Long South which is the last phase.

Many of the main trunk transfer systems rely on pressure mains because of the topography of the area. Consequently, collector sewer systems will need to be constructed either with or following closely behind the trunk system.

The tentative construction details for pumping stations and sewerage systems are listed in Tables 2.1 and 2.2 respectively.

Table 2.1: Tentative construction details of pumping stations

Package	Pumping Stations	Dry Weather Flow (m³/day)	Excavation Depth (m)	Dimension (m x m)
2A-1T (Conforming and Alternative)	Yuen Long Effluent (OP1/AP1)	14,760	15	100 x 70
2A-2T and 2B-1T	Cassino Line (P5)	200	9	25 x 20
2A-2T and 2B-1T	Fan Tin San Tsuen/ San Lung Tsuen (P4)	1,000	13	40 x 30
2A-2T and 2B-1T	San Tin (P3)	1,200	10	40 x 30
2A-2T and 2B-1T	Tam Mei Camp (P2)	100	11	40 x 30
2A-2T and 2B-1T	Ngau Tam Mei (P1)	13,000	13.5	40 x 40
2A-3T	Mong Tseung (A2)	100	10	40 x 30
2A-3T	Lau Fau Shan (A1)	200	10	25 x 20
2B-2T	Shan Ha Tsuen (B1)	400	10	40 x 30
2B-2T	Nga Yiu Tau (B6)	500	9	25 x 20
2B-2T	Pak Sha Tsuen (B7)	500	9	25 x 20
2B-2T	Sham Chung Tsuen (B3)	1,000	7	25 x 20
2B-2T	Muk Kiu Tau Tsuen (B2)	900	8.5	40 x 30
2B-2T	Shiu Tsiu San Tsuen (B4)	1,000	7.5	25 x 20
2B-2T	Shung Ching San Tsuen (B5)	1,200	9	25 x 20

Legend:		- Designated Elements

		- Non-Designated Elements

Table 2.2: Tentative construction details of sewerage system

Package	Twin Rising Mains (TRM)/ Gravity Sewers (GS), Diameter (m)	Excavation Width (m)	Excavation Depth (m)	Length (m)
2A-1T	TRM, 1.4m	5	3.8	8000
2A-2T	TRM, 0.2m	1.4	2.6	1460
and 2B-1T	TRM, 0.3m	1.9	2.6	450
	TRM, 0.3m	1.9	2.7	125
	TRM, 0.4m	2.3	27	1100
	TRM, 0.6m	2.95	2.9	1450
	GS, 0.525m	1.2	5	420
	GS, 0.525m	1.2	6.6	750
	GS, 0.6m	1.35	5.5	1000
	GS, 0.75m	1.5	6.5	2000
	GS, 1.05m	2.05	6	800
2A-3T	TRM, 0.2m	1.4	2.6	510
	TRM, 0.3m	1.9	2.6	1535
	GS, 0.45m	1.15	3.5	315
	GS, 0.45m	1.15	6	1125
2B-2T	TRM, 0.15m	1.2	2.6	165
	TRM, 0.2m	1.4	2.6	270
	TRM, 0.25m	1.5	2.6	90
	TRM, 0.3m	1.9	2.6	330
	GS, 0.3m	0.75	4	750
	GS, 0.3m	0.75	6	710
	GS, 0.375m	1.05	3.5	720
	GS, 0.375m	1.05	4	710
	GS, 0.375m	1.05	4.5	450
	GS, 0.375m	1.05	5	1375
	GS, 0.375m	1.05	6.5	885
	GS, 0.45m	1.15	6	390
	GS, 0.45m	1.15	7	580

The proposed trunk will convey sewerage to the rest of the system and reach the YLSTW for secondary treatment. Afterwards, the effluent from YLSTW will be conveyed to SWSTW for centralized disinfection through YLSTW Effluent Pipeline. Discharge of final effluent will be through the NWNT effluent tunnel to the outfall at Urmston Road.

2.2 Neighbouring Environment

Except for Tin Shui Wai area, the Sitesare located within rural areas where the population density is low. During site inspections, it was observed that the work nature in general was car repairing, container parking, low-density residential, and some industrial activities. Details of sensitive receivers are identified in Sections 6 - 15.

2.3 Planning Issue

In accordance with the latest approved Outline Zoning Plan (OZP), there are several Sewage Pumping Stations located in areas with incompatible land use. According to the Notes attached to the OZP, the proposed use will require planning permission from the Town Planning Board (TPB). As for the proposed sewers, the development is always permitted and no planning permission from the TPB is required. In accordance with the DSD practice, the planning application / rezoning exercise will be conducted during the detailed design stage before the gazetting plans are issued. Planning application/rezoing request will be required for the proposed sewage pumping stations in various zones of respective OZPs. The existing types of landuse are listed in Table 2.3.

Table 2.3: Types of land use for the pumping stations

Works Package	Works Item	Location	Current Land Status	Type of Land Use (Reference)
Tin Shui Wai and San Wai Areas
2A-1T	OP1	Pumping station in the north of YLSTW (Yuen Long Effluent Pumping Station)[1]	Vacant site (non fish pond) – disturbed urban land	Conservation Area (S/YL-LFS/5)
Tin Shui Wai and San Wai Areas
Alternative scheme of 2A-1T	AP1	Pumping station in the north of YLSTW (Yuen Long Effluent Pumping Station)[1]	Vacant site (non fish pond) – disturbed urban land	Conservation Area (S/YL-LFS/5)
Ngau Tam Mei and San Tin Areas
2A-2T	P1	Ngau Tam Mei sewage pumping station	Construction site next to drainage channel	Open Storage (S/YL-NTM/8)
and	P2	Tam Mei Barracks sewage pumping station (Tam Mei Camp Sewage Pumping Station)	Barrack (restricted) area	Comprehensive Development Area (S/YL-NTM/8)
2B-1T	P3	San Tin sewage pumping station	Temporary site office	Residential (Group D) (S/YL-ST/5)
	P4	San Lung Tsuen sewage pumping station	Vacant site next to a toilet	Village Type Development (S/YL-ST/5)
	P5	San Tin Barracks sewage pumping station (Cassino Line Sewage Pumping Station)	Construction site next to drainage channel	-
Lau Fau Shan and Mong Tseng Areas
2A-3T	A1	Lau Fau Shan sewage pumping station	Vacant site next to a temporary car park	Residential (Group D) (L/YL-LFS/5)
2A-3T	A2	Mong Tseng sewage pumping station	Occupied by local villagers	Village Type Development (S/YL-LFS/5)
Shap Pat Heung Area
2B-2T	B1	Shan Ha Tsuen sewage pumping station	Vacant site next to village houses	Village Type Development (S/YL-TYST/6)
	B2	Muk Kiu Tau Tsuen sewage pumping station	Vacant site next to village houses	Agriculture & Village Type Development (S/YL-TT/10)
	B3	Sham Chung Tsuen sewage pumping station	Vacant site next to village houses	Residential (Group D) (S/YL-TT/10)
	B4	Shui Tsiu San Tsuen sewage pumping station	Vacant site next to village houses	Village Type Development (S/YL-TT/10)
	B5	Shung Ching San Tsuen sewage pumping station	Vacant site next to village houses	Village Type Development (S/YL-TT/10)
	B6	Nga Yiu Tau sewage pumping station	Vacant site next to village houses	Residential (Group D) & Village Type Development (S/YL-TT/10)
	B7	Pak Sha Tsuen sewage pumping station	Vacant site next to village houses	Village Type Development (S/YL-TYST/7)

Remark [1]: DSD had already confirmed the Option 1 was the only feasible site location for the construction of the proposed YLEPS in terms of engineering feasibility and other operational/maintenance considerations.

The proposed PME locations (detailed in the noise section) at the open area of San Lung Tsuen fall within the “Village Type Development” zone on the approved San Tin Outline Zoning Plan No. S/YL-ST/5. Planning permission from the Town Planning Board is required.

Except for several small sections encroaching earth bunds of four fish ponds at Shan Pui within the Wetland Buffer Zone (Fish ponds are actually located within the WSD Reserve and no work will be carried out within the WSD boundary area), most of the sewers alignment will be located underneath existing/future roads.

It has been reminded by PlanD that a rezoning request for OP1/AP1 shall be carried out well in advace before the commencement of the project to the Town Planning Board (TPB) for consideration as the site falls within an area zoned “Conservation Area” (CA). According to the Notes of the OZP, ‘sewage pumping station’ is neither a Column 1 nor 2 use of the CA zone. Meanwhile, the site also falls within the Wetland Conservation Area (WCA) according to the TPB Guidelines for Application for Developments within Deep Bay Area under section 16 of the Town Planning Ordinacne (TPB PG No. 12B). According to the Guidelines, the planning intention of the WCA is to conserve the ecological value of the fish ponds which form an integral part of the wetland ecosystem in the Deep Bay Area. It comprises the existing and contiguous, active or abandoned fish ponds in the Deep Bay Area, which should all be conserved. New development within the WCA would not be allowed unless it is required to support the conservation of the ecological value of the area or the development is an essential infrastructural project with overriding public interest. Any such development should be supported by an ecological impact assessment during the rezoning request.

The proposed landscaping planting/compensation area at the grassy area of San Pun Pond falls within an area designated for Kam Tin and Yuen Long Drainage Channels on the approved Lau Fau Shan and Tsim Bei Tsui Outline Zoning Plan (OZP) No. S/YL-LFS/5. This area also falls within the Wetland Conservation Area (WCA) according to the Town Planning Board Guidelines for Application for Developments within Deep Bay Area (TPB PG-No. 12B), planning application to the Town Planning Board is also required.

2.4 Preliminary Construction Programme

The tentative schedule to commence the construction works is in mid 2005 and to complete in late 2007.

2.5 Concurrent Projects

The following potential interfacing projects have been identified in the DSD study brief:

· West Rail Projects

· Main Drainage Channels in Yuen Long, Kam Tin, Ngau Tam Mei and San Tin

· Yuen Long Bypass Floodway

· Widening of Yuen Long Highway

· The Planning and Development Study on NWNT

· Deep Bay Link

· Yuen Long and Kam Tin Sewerage and Sewage Disposal Stage I

· Upgrading of San Wai Sewage Treatment Works and Expansion of Ha Tsuen Pumping Station

· Light Rail Expansion in Tin Shui Wai

· Tin Shui Wai Further Development

· Ping Ha Road Improvement – Remaining Works

Other following projects are located within the region but would not contribute cumulative impact:

· Relevant RPIS projects (Based on rezoning and section 16 information from Planning Department, these projects are small (e.g. small village houses) and not closed to the current sites. Therefore, the cumulative impact is insignificant and can be discarded from cumulative impact assessment);

· Fung Lok Wai Development and nearby fish ponds are far away from the site, and only a small section of 50m sewer will be laid at the same time. The potential cumulative impact is minimal (details in the ecological section);

· Northern Link (Planned at 2011 to 2016 that will not be concurrent to this project);

· Regional Express Line (Currently neither solid programme nor concrete planning before implementation of the DSD project. The need for development will depend on future cross-boundary rail passenger growth);

· Hung Shui Kiu Development (Referring to the information from DSD, PlanD and TDD, there is no plan to proceed with the Hung Shui Kiu Development before construction of the DSD project).

The construction programmesand the separation distances of the genuine concurrent projectswithin the study limit are listed out to identify whether there is any overlapping period (Tables 2.4 & 2.6).

Table 2.4: Interfacing Projects for Package 2A-1T (Tin Shui Wai Area) and Package 2A-3T (Lau Fau Shan Area)

Item	Concurrent Project	Scheduled Construction Period ^[2]		Overlapping Months	Distance to the site boundary ^[2]	Potential to Cause Cumulative Impact
Item	Concurrent Project	Start	Complete	Overlapping Months	Distance to the site boundary ^[2]	Potential to Cause Cumulative Impact
1	DD901 – West Rail Environmental Support Services Essential Public Infrastructure Works: Yuen Long, Tin Shui Wai and Tuen Mun Centre	May 99	Nov 03	0	-	û
2	Tin Shui Wai Phase 4 Extension	2001	2004	0	-	û
3	Light Rail Transit (LRT) Extension in Tin Shui Wai Reserve Zone and Grade Separation of the LRT with Pui To Road and Tsing Lung Road in Tuen Mun	2001	2004	0	-	û
4	Widening of Yuen Long Highway between Lam Tei and Shap Pat Heung Interchange	Aug 2003	Dec 2005	6	>500m	û
5	Yuen Long Bypass Floodway - Feasibility Study	Mar 2001	Dec 2003	0	-	û
6	Deep Bay Link (San Wai Section)	Jul 2003	Jun 2006	12	-	ü
6	Deep Bay Link (Lau Fau Shan Section)	Jul 2003	Jun 2006	12	>500m	û
7	San Wai Sewerage Treatment Works	2004	2007	30	<300m	ü
8	Shenzhen Western Corridor	Mar 2003	Dec 2005	6	>500m	û
9	Hung Shui Kiu New Development Area (HSK NDA)	After this project	After this project	0	<300	û
10	Ping Ha Road Improvement Remaining Works	---	2006	6	<300m	ü
11	Alternative 4 Bypass Culvert	2003	2007	18	-	ü
12	Main Drainage Channels and Poldered Village Protection Schemes for San Tin^[1]	Jun 2001	Dec 2003	0	-	û
13	Yuen Long and Kam Tin Sewerage and Sewage Disposal Stage 1 (1B-2T)	Aug 2004	Feb 2008	30	<300m	ü
14	Tin Shui Wai Further Development	July 1998	2003	0	-	û
15	157DS Phase 3B/3C San Wai and Tung Tau Tsuen	June 2005	June 2007	24	<300m	ü

Note [1]: MDC-Eastern Section is more than 300 m from the present project

[2] The setback distance and construction programme have been provided for genuine concurrent projects only (ie. Both within the study limit and constructed at the same time as the DSD project.)

Table 2.5: Interfacing Projects for Package 2B-2T (Shap Pat Heung Area)

Item	Concurrent Project	Scheduled Construction Period^[2]		Overlapping Months	Distance to the site boundary^[2]	Potential to Cause Cumulative Impact
Item	Concurrent Project	Start	Complete	Overlapping Months	Distance to the site boundary^[2]	Potential to Cause Cumulative Impact
1	DD901 – West Rail Environmental Support Services Essential Public Infrastructure Works: Yuen Long, Tin Shui Wai and Tuen Mun Centre	May 99	Nov 03	0	-	û
2	Tin Shui Wai Phase 4 Extension	2001	2004	0	-	û
3	Light Rail Transit (LRT) Extension in Tin Shui Wai Reserve Zone and Grade Separation of the LRT with Pui To Road and Tsing Lung Road in Tuen Mun	2001	2004	0	-	û
4	Widening of Yuen Long Highway between Lam Tei and Shap Pat Heung Interchange	Aug 2003	Dec 2005	6	<500m	ü
5	Yuen Long Bypass Floodway - Feasibility Study	Mar 2001	Dec 2003	0	-	û
6	Deep Bay Link	Jul 2003	Jun 2006	12	>500m	û
7	San Wai Sewerage Treatment Works	2004	2007	30	>500m	û
8	Shenzhen Western Corridor	Mar 2003	Dec 2005	6	>500m	û
9	Hung Shui Kiu New Development Area (HSK NDA)	After this project	After this project	0	>500m	û
10	Ping Ha Road Improvement Remaining Works	---	2006	6	>500m	û
11	Main Drainage Channels and Poldered Village Protection Schemes for San Tin^[1]	Jun 2001	Dec 2003	0	-	û
12	Yuen Long and Kam Tin Sewerage and Sewage Disposal Stage 1 (1A-1T)	Aug 2003	Feb 2006	8	>500m	û
13	Tin Shui Wai Further Development	July 1998	2003	0	-	û
14	157DS Phase 2 Yuen Long South Pumping Station, Rising Main to Castle Peak Road and Sewers	Jan 2003	May 2006	12	<300m	ü
15	274DS Phase 1 Shap Pat Heung Rising Main and Gravity Sewer; Au Tau Sewage Pumping Station and Ancillary Works	Jan 2003	May 2006	12	<300m	ü
16	274DS Phase 7A/ 7B San Sang Tsuen and Tin Sum, Shan Ha and Tai Tong Tsuen	June 2007	July 2009	6	<300m	ü

Note [1]: MDC-Eastern Section is more than 300 m from the present project

[2] The setback distance and construction programme have been provided for genuine concurrent projects only (ie. Both within the study limit and constructed at the same time as the DSD project.)

Table 2.6: Interfacing Projects for Package 2A-2T and 2B-1T (Ngau Tam Mei Area)

Item	Concurrent Project	Scheduled Construction Period ^[2]		Overlapping Months	Distance to the site boundary ^[2]	Potential to Cause Cumulative Impact
Item	Concurrent Project	Start	Complete	Overlapping Months	Distance to the site boundary ^[2]	Potential to Cause Cumulative Impact
1	DD901 – West Rail Environmental Support Services Essential Public Infrastructure Works: Yuen Long, Tin Shui Wai and Tuen Mun Centre	May 99	Nov 03	0	-	û
2	Tin Shui Wai Phase 4 Extension	2001	2004	0	-	û
3	Light Rail Transit (LRT) Extension in Tin Shui Wai Reserve Zone and Grade Separation of the LRT with Pui To Road and Tsing Lung Road in Tuen Mun	2001	2004	0	-	û
4	Widening of Yuen Long Highway between Lam Tei and Shap Pat Heung Interchange	Aug 2003	Dec 2005	6	>500m	û
5	Yuen Long Bypass Floodway - Feasibility Study	Mar 2001	Dec 2003	0	-	û
6	Deep Bay Link	Jul 2003	Jun 2006	12	>500m	û
7	San Wai Sewerage Treatment Works	2004	2007	30	>500m	û
8	Shenzhen Western Corridor	Mar 2003	Dec 2005	6	>500m	û
9	Hung Shui Kiu New Development Area (HSK NDA)	After this project	After this project	0	>500m	û
10	Ping Ha Road Improvement Remaining Works	---	2006	6	>500m	û
11	Main Drainage Channels and Poldered Village Protection Schemes for San Tin ^[1]	Jun 2001	Dec 2003	0	-	û
12	Yuen Long and Kam Tin Sewerage and Sewage Disposal Stage 1 (1A-1T)	Aug 2003	Feb 2006	8	< 300m	ü
13	Tin Shui Wai Further Development	July 1998	2003	0	-	û
14	92CD Package NTM1	Nov 2003	Jun 2006	12	>500m	û

Note [1]: MDC-Eastern Section is more than 300 m from the present project

[2] The setback distance and construction programme have been provided for genuine concurrent projects only (ie. Both within the study limit and constructed at the same time as the DSD project).

2.6 Future Planned Use

The works packages 2A-1T and 2A-3T would have interface with the Hung Shui Kiu developments, notably the planned Hung Shui Kiu New Development Area (HSK NDA) and Hung Shui Kiu North New Development Area (HSK North NDA). The issue is further complicated by the revised alignment of Deep Bay Link (DBL) and the potential Easterly Link Road being studied under the DBL D&C Assignment. The corresponding Recommended Outline Development Plans will therefore be subject to further changes, but confirmation and formal approval of these plans would not likely meet the programme of this Study. In view thereof and after some deliberation with DSD, Planning Department (PlanD) and Territory Development Department (TDD), it is suggested that a worst-case land use plan for HSK and HSK North NDAs is to be developed based on best-known information currently available, for assessment purpose of this Study. With reference to the latest information from the “Consultation Digest of the Development Proposals for Hung Shui Kiu Consultation Digest, Planning and Development Study on North West New Territory, 1999”, the proposed HSK Development Plan with incorporation of the latest DBL alignment has been extracted. The use of this plan will have to be agreed by the relevant departments including DSD, PlanD, TDD and EPD (Figure 2.1).

Furthermore, the originally proposed alignment of a section of Yuen Long effluent pipeline may have conflicts with the planned developments in HSK North. One possibility would be to re-align the pipeline along Ping Ha Road instead of through future CDA area. In agreement between DSD, PlanD and TDD, the revised alignment will be further reviewed during detailed design stage by DSD, if necessary.

Based on DSD, PlanD and TDD latest information, the development programme for HSK NDA and HSK North NDA will not conincide with the construction of the DSD project; therefore, there is no cumulative impact during construction phase. With regard to this EIA study, the key concern will be on the potential impacts during the operational phase. Representative Sensitive Receivers for the future planned use has been identified at the worst-case scenario. Nonetheless, these locations are beyond 500m from the site and therefore potential impact during operational phase is not anticipated.

Other planned uses located at San Tin NDA and Tin Shui Wai (rezoning/Section 16 application) have also been reviewed, it is identified that there are other existing sensitive receiver locations closer to the pollution source. Therefore, those existing sensitive receivers were instead selected as the worst-case scenario.

Description	Completed/ Approved Date
Yuen Long and Kam Tin Sewerage Masterplan Study	Mar 1992
PPFS for Yuen Ling and Kam Tin Sewerage and Sewage Disposal	Jan 1998
Supplementary PPFS for Yuen Ling and Kam Tin Sewerage and Sewage Disposal	Jan 1999
Final Report on Review of Yuen Long and Kam Tin Sewerage and Sewage Treatment Requirements by EPD, Jan 1999	Jan 1999
Development Proposals for Hung Shui Kiu Consultation Digest, Planning and Development Study on North West New Territory	1999
Final Report on 1st Stage of Planning and Development Study on North West New Territories	Sep 2001
Agreement No. CE31/99 (EP), Yuen Long and Kam Tin Sewerage and Sewage Disposal Stage, Final EIA (DE) Report	26 Aug 2002
Agreement No. CE31/99 (EP), Yuen Long and Kam Tin Sewerage and Sewage Disposal Stage, Environmental Study (NDE) Report	Mar 2002
PWP Item 4215DS, Yuen Long and Kam Tin Sewerage and Sewage Disposal Stage II, Package 2A-1T, Yuen Long Effluent Pipeline, Adoptive Review	Sep 2001
Tuen Mun Sewerage, Eastern Coastal Sewerage Extension, Final Environmental Impact Assessment Report	7 June 2000
Agreement No. CE 109/98, Deep Bay Link Investigation and Preliminary Design, Environmental Impact Assessment	13 Sep 2002
Environmental Impact Assessment Study for Upgrading and expansion of San Wai Sewage Treatment Works and Expansion of Ha Tsuen Pumping Station, CE 62/2000	12 May 2003
Outline Zoning Plans	2002/2003

5.0 considerations on Alignment options and alternative pumping station locations

5.1 Consideration on Alternative Alignment (on Designated Element)

For the design of the Yuen Long Effluent pipline, two alignment options have been reviewed. Considerations have been given comprehensively in order to identify the preferred alignment that would achieve an optimal balance between environmental, engineering, connectivity, work programme etc, in accordance with the latest available information.

5.1.1 Conforming Scheme of 2A-1T (Figure 1.4 & Figures 1.4.1 to 1.4.6)

The proposed works under the conforming scheme are divided into six works items. The whole section is 7,350m long of twin rising mains of 1400mm in diameter. Major parts of the sewage alignment (2,140m) and the Yuen Long Effluent Pumping Station will be located within the Deep Bay Buffer Zone, Wetland Conservation Area and Wetland Buffer Area.

5.1.2 Alternative Scheme of 2A-1T (Figure 1.1 & Figures 1.1.5 to 1.1.9)

The proposed works under the alternative scheme are divided into seven works items. The whole section has been reduced to 6,990m long of twin rising mains of 1400mm in diameter. Except for the small-scale Yuen Long Effluent Pumping Station (same SPS location as the Conforming Scheme) on a plantation area, the alignment will run away from the Deep Bay Buffer Zone. This factor, together with other considerations as detailed in Section 5.2, concluded this scheme as the Preferred Option.

5.2 Evaluation of Alignment Options

The evaluation criteria are based on key factors associated with both the environmental impact and engineering constraints, as discussed in the following sections.

The 2A-1T conforming scheme was considered as a “No-built” option, while the 2A-1T alternative scheme was concluded as the preferred option. A summary of the critical factors that dictated the route selection process is given below.

5.2.1 Ecological and Fishery Impacts

For the conforming alignment, rising mains will be laid within Deep Bay Buffer Zone, and some existing fishponds and wetland areas will be run across. Sheet piles will be driven into the ground and excavation and extensive dewatering will be required. The affected fishponds are not isolated, and support moderate bird abundance (see Section 13.3). These fishponds are also feeding habitats of nesting ardeids in the Shing Uk egretry (same as the egretry at the north of Wan Chau Fresh Water Service Reservoir in the EIA study brief). It is anticipated that the construction of rising mains and associated construction haul road will cause significant impact to the environment. In accordance with the Guidelines TPB PG-No. 12B, the planning intention of the WCA is to conserve the ecological value of the fishponds which form an integral part of the wetland ecosystem in the Deep Bay Area. However, a lot of fishponds will need to be resumed/dewatered in order to carry out the construction and subsequent maintenance work. This alignment will cause significant impact on the existing and contiguous, active or abandoned fish ponds in the Deep Bay Area (2,140m of sewer within WCA/WBA with fish ponds). With such a large area of impact, compensation or enhancement by provision of more wetland areas in the area are not feasible. Since such alignment will have detrimental effect the conservation of the ecological value in the WCA, negative disturbance impact and major loss in wetland function, the development will not be allowed. Excessive noise and dust generation from active construction site and haul road would affect wild life within the CA.

The alternative alignment would avoid these fishponds and other impact on the wetland functions; and therefore is preferred.

5.2.2 Landscape Impact

Impacts on Landscape Resources

The Conforming Alignment, at its departure from the alternative scheme at the north east of the pipeline, passes through an area of RAMSAR protected fishponds. The alignment is likely to affect key landscape resources including fishponds; waterways and creeks and reed beds. The sensitivity of these landscape resources is generally high and the residual impact significance is likely to be substantial during the construction phase and moderate during the operational phase, as there will be little opportunity to mitigate impacts.

By contrast, the key landscape resources affected by the Alternative Alignment are groups of trees and fields. These have a medium to low sensitivity to change and residual impacts will not be significant for both the construction and operational phases as these impacts can be mitigated to a significant extent.

Impacts on Landscape Character

The landscape character of the Conforming Alignment is generally an open and simple large-scale landscape of fishponds. The sensitivity to change of this landscape is high and the works will during the construction stage, generally contrast unfavourably with the rural and open character of the landscape. Residual impacts on landscape character are likely to be moderate for the construction phase and slight for the operational phase.

By contrast, the landscape character of the Alternative Alignment is varied, slightly degraded and incoherent as it passes through industrial areas, villages (Shing Uk Tsuen & Tai Tseng Wai) and rural areas. The sensitivity of this landscape is variable, from low to high. This means that the disturbance caused by the Works is unlikely to contrast significantly with existing landscape character. Residual impacts for both the construction and operational phases will be insubstantial.

As identified above, landscape impacts are likely to be consistently higher for the Conforming Alignment than for the Alternative Alignment.

5.2.3 Visual Impact

Impacts on Visual Sensitive Receivers

Visual receivers likely to be affected by the Conforming Alignment (OS3-5) are residential (high sensitivity), occupational (low sensitivity) and travellers (medium sensitivity). The number of these receivers is not very high. They will have partial - full view of the construction works. However, given the indifferent existing character of views across this landscape, residual impacts for both the construction and operational phases are likely to be insubstantial.

Visual receivers affected by the Alternative Alignment (AS5-AS6) will be largely occupational (low sensitivity) and travellers (medium sensitivity). The number of these receivers is few and they will have a partial - full view of the construction works. Again, given the indifferent existing character of views across this landscape, residual impacts for both the construction and operational phases will be insubstantial.

Therefore, visual impacts are likely to be consistently higher for the Conforming Alignment than for the Alternative Alignment.

5.2.4 Cultural Heritage Impact

The conforming alignment will encroach the permitted burial ground YL/64 and there will be potential cultural heritage and Fung Shui impacts. It will also result in impacts on potential archaeological deposits on the lower slopes of the hill to the north of Ng Uk Tsuen.

Alternative scheme was assessed during desk-based research and a field evaluation. The desk-based results indicate the area of the sewer alignment between the historic villages of Tai Tseng Ng Uk Tsuen, Tai Tseng Wai and Shing Uk Tsuen has archaeological potential. Archaeological monitoring is recommended during the construction works. The lower hill slopes at Wang Chau was assessed to have no archaeological potential after a field evaluation was carried out.

5.2.5 Noise Impacts

For the conforming alignment, rising mains will be laid within Deep Bay Buffer Zone with some low rise village houses. Whereas, the alternative alignment will pass through some low-rise residential building next to Yuen Long Industrial estate and potential construction noise impact will be anticipated. With the incorporation of appropriate mitigation measure, the noise impact for both conforming and alternative schemes will be reduced to practically low level. It is anticipated that the noise impact will be similar in magnitude for both schemes.

5.2.6 Air Quality Impacts

For the conforming alignment, rising mains will be laid within Deep Bay Buffer Zone, and dust generated from active construction site and haul roads would affect some low rise village houses. Whereas, the alternative alignment will pass through some low-rise residential building next to Yuen Long Industrial estate. Potential dust impact will be anticipated. With the incorporation of good site practice, dust impact for both conforming and alternative schemes will be reduced to acceptable level. It is anticipated that the dust impact will be similar in magnitude for both schemes.

5.2.7 Waste Management and Land Contamination

For the conforming alignment, the alignment will encroach the Inner Deep Bay Special Measure Zone (SMZO and the length of sewer will be longer and the amount of excavated material will be larger. Whereas, for the alternative alignment, the sewerage will pass through industrial areas, where the possibility of land contamination will be relatively higher. Nonetheless, with a proper waste management plan and proper conformatory testing before treatment, the potential impact on both alignments will be similar.

5.2.8 Resumption of Private Buildings/Lands

For the conforming alignment, resumption of a number of private lots and encroachment upon the permitted burial ground YL/64 will be required for the rising mains. For construction and future maintanance, large-scale area of fish ponds need to be resumed within the WCA and CA. Provision of wetland compensation within the WCA/CA would not be feasible. The time for land resumption will be lengthened and the cost will be higher.

5.2.9 Compatibility with Future Land Use

For the conforming alignment, resumption of a number of private lots and encroachment upon the permitted burial ground YL/64 will be required for the rising mains. There will be potential cultural heritage and Fung Shui impacts. The time for land resumption will be lengthened, and the cost on remediation of environmental impacts will be higher. The alignment of the alternative scheme will be laid along future road, and there is no constraint on future development. Nonetheless, the alignment of the conforming scheme may lay across existing and future planned area. Further land resumption and agreement on land use would be required.

5.2.10 Accessibility

For the conforming alignment, rising mains will be laid within Deep Bay Buffer Zone. Part of the construction site is fallen within the restricted area and special permit is required for entry and construction. The arrangement for access will be more difficult.

5.2.11 Engineering

The proposed works of conforming scheme is 7,350m long of twin rising mains, while that for alternative scheme is 6,990m long. Higher pressure and more energy are required to convey the sewage in the conforming scheme. Septicity problem will be much prominent with a longer length of rising mains. Operating and maintenance costs will also be much higher. Massive dewatering would be required at fishponds during construction; otherwises, future settling and damage to sewer would be anticipated;

5.3 Evaluation Results

In accordance with the arguments discussed above, a summary on the evaluation of the 2 options is given below.

Table 5.1 : Summary of reasoning for route alignment selection

	Alignment Options ⁽¹⁾
Criteria	Conforming Scheme (Yuen Long Effluent pipline) as the “No-built” Option	Alternative Scheme (Yuen Long Effluent pipline) as the Preferred Option
Environmental Factors
Ecology and Fishery	Excessive noise and dust generation from active construction site and haul road would affect wild life within CA; Significant impact with major construction works within Deep Bay Wetland Conservation Area (WCA) and Conservation Area; Affecting feeding habitats of nesting ardeids in the Shing Uk egretry and have detrimental effect the conservation of the ecological value in the WCA; Affecting fish pond and wetland and have negative disturbance impact and major loss in wetland function.	Minor impact with only YLEPS (on a urbanized/ disturbed land) within the Deep Bay WCA; In accordance with the ecological assessment, there will be no residual impact and there is no net loss in wetland function.
Landscape resources/character	High impact with significant portion of construction works within RAMSAR protected fishponds; Sensitivity of the landscape resources is high but little opportunity to mitigate; Sensitivity to change on landscape character is high and unfavourable.	Only affect groups of trees and fields; Residual impact will not be significant; The landscape character varies and the residual impact will be insubstantial
Visual resources/character	Affected receivers will be from high sensitivity to low sensitivity; Indifferent existing character of views and the residual impact are insubstantial.	Affected receivers will be from medium sensitivity to low sensitivity; Indifferent existing character of views and the residual impact are insubstantial.
Heritage Buildings	Some impact on the permitted burial ground YL/64; Potential Fung Shui impact; Potential impact on archaeological deposits on the lower hill slopes at the north of Ng Uk Tsuen	Potential impact needs to be further confirmed by archaeological monitoring; Desktop study indicated the area of the sewer alignment between the historic villages of Tai Tseng Ng Uk Tsuen, Tai Tseng Wai and Shing Uk Tsuen has archaeological potential. Archaeological monitoring is recommended during the construction works.
Waste generation & contaminated sediment	No impact with proper waste management plan and contaminated land treatment.	No impact with proper waste management plan and contaminated land treatment.
Noise	Short term localized construction noise impact; Residual impact after mitigation at some NSRs	Short term localized construction noise impact; Residual impact after mitigation at some NSRs
Air Quality	No major impact at ASR with good site practice and controlled requirement under APCO.	No major impact at ASR with good site practice and controlled requirement under APCO.

Other Factors
Land/Building resumption	For construction and future maintanance, large-scale area of fish ponds need to be resumed within the WCA and CA; Provision of wetland compensation within the WCA/CA would not be feasible; Resumption of public lots; Longer time for land resumption.	Not required
Compatibility with Future Land Use	Potential impact; Encroachment on burial ground YL/64; The land use in NDA and alignment to be further confirmed with various department.	No impact; Alignment has already taken into account in the future NDA developments.
Accessibility	Area within restricted area and special permit is required; Poor accessibility with construction of haul road within Buffer Zone	No problem
Engineering	Massive dewatering is required at fishponds; otherwises, future settling and damage of sewer would be anticipated; Higher construction and operating cost; Septicity problem for longer rising mains.	Less construction and operating cost.

Results indicate that there are negative distubance impact and will have detrimental effect on the Wetland fuction of the conforming scheme in both environmental and engineering considerations. Since the major part of the alignment will be fallen within the Deep Bay Buffer Zone where resumption of a large area of fish pond is anticipated. The integral part of the wetland ecosystem in the Deep Bay Areas, including the existing and contiguous, active or or abandoned fish ponds, will have severely detrimental impacts and is considered as a “No-built” Option. Comparison has been made with the alternative scheme of 2A-1T, and it is found that with the provision of mitigation measures, there is no major environmental impact and therefore selected as the preferred option for further focused assessment.

5.4 Consideration on Alternative Pumping Station Locations

5.4.1 Alternative Sites for YLEPS (Designated Element)

For the selection of the Yuen Long Effluent pumping station, three alternative sites have been investigated in the vicinity of YLSTW (Appendix 5.1). DSD has therefore conducted a detailed utility search, ground review and engineering investigations on the alternative sites and other nearby areas. The following observations were made by DSD during the planning stage:

· The proposed size of YLEPS is confirmed to be the minimum requirements for construction, operation and maintenance purposes.

· The Wetland Conservation Area (WCA) is located on three sides (N, E and W) of YL Sewage Treatment Plant (YLSTW). There is limited land to house the future YLEPS.

· On the west side of the YLSTW, the topograph (hill) is higher than the STW and natural gravity flow of effluent is impossible. In addition, the hill is a local permitted burial ground. Therefore, siting of YL Effluent Pumping Station on the west side is not engineering feasible.

· On the east side, it is the Shan Pui River, both the river and the adjoining undisturbed fishpond at the C.A will be affected during construction and operational phase. The impact will be significant.

· For Option 2 (existing public car park in the Yuen Long Industrial Estate), based on the existing utility record and available space of YLSTW, it is observed that apart from the 3.5m wide carriageway, there is no other available space within YLSTW large enough to accommodate the 1.8m diameter gravity sewer conveying the treated effluent from the discharge outfall of YLSTW to the YLEPS. To make sufficient space for the gravity sewer within the 3.5m wide carriageway which is congested with existing underground utilities (DN450 gravity sewers, DN375 storm water drains and their associated manholes), diversion of the utilities must be required leading to substantial modification works to YLSTW. It will interrupt the treatment process and disturb the normal operation of YLSTW. In addition, the proposed gravity sewer has to be laid at depths of about 7m to achieve gravity flow. Deep sewer will make the future inspection and maintenance difficult and increase the risk of damaging nearby structures/utilities within YLSTW. Therefore, DSD considers this option is a "No-built" option because of the extreme engineering constraint. However, there is also objection from the management agency of the Option 2 site.

· For Option 3 (100m south of YLSTW), the exact route within the YLSTW as option 2 will be followed. Based on the same considerations, DSD also considers this option is a "No-built" option because of the extreme engineering constraints.

· Other vacant areas in the YL Industrial Estate are too far away, and natural gravity flow design is impossible. The utility within the area is also not avoidable. Therefore, it is not considered engineering feasible.

· For Option 1 (current selected location), the site was originally recommended in the Yuen Long and Kam Tin Sewerage Master Plan published by EPD in 1992 and its subreview in 1999. The current land status of the site is Government land and resumption of private land lots is not required. Based on the existing utility record of YLSTW, no major underground utilties in the vicinity of the proposed 1.8m gravity sewer conveying the treated effluent from the discharge outfall of YLSTW to the YLEPS, substantial modification works to YLSTW resulting from diversion of utilities will not be required. In addition, the site was filled up many years ago. Currently, there are only few immature plantations in the area. The future YLEPS is a minor encroachment of the "disturbed urbanised land" within the WCA. The sewer will be laid underneath existing road or earth bund of fish ponds, of which the construction works will be temporary in nature. Based on the detailed EIA findings on ecological, landscaping, visual and other aspects, there is no significant residual impact on the environment.

· In short, judging from the respective pros and cons of the three options as well as the surrounding site conditions as mentioned above, Option 1 is the most preferable and viable site option for the YLEPS from engineering, environmental and land points of view.

Detailed engineering justifications, maintenance problems and supportive reasoning have been sent to relevant authorities to justify Option 1 (the current design) is the only feasible option. Other options, including Options 2 and 3 are technically/engineering infeasible. The correspondences are listed in Appendix 5.1 for reference.

5.4.2 Alternative Sites for San Lung Tsuen SPS (Non-Designated Element)

For the selection of the San Lung Tsuen pumping station, DSD has conducted a detailed utility search, ground review and engineering investigations on the site. The following considerations were made for selecting a pumping station and rising mains systems:

· Under the review of PWP Item No. 4215DS, sewege generated from the San Tin catchment area should be conveyed to the proposed trunk sewer located downstream at Castle Peak Road;

· The topographical levels at the Castle Peak Road and the catchment area are in the range of +9.4mPD and +4.0mPD. Therefore, if gravity sewer system is adopted, construction of deep sewer at depth of 7m below ground level will be required;

· All the nearby villages are limited in space. Therefore, deep sewers will make the construction as well as future inspection and maintenance difficult and increase the risk of damaging nearby village houses/utilities/structures;

· Other villages in this catchment are also packed with village houses. Isolated ancestral halls or declared momument can be found in most villages, and are unavoidable in terms of engineering design;

· Deep sewers construction will be timely and costly. Long construction period will also cause inconvenience to the local villagers;

· Pumping station with pressure mains at shallow depths is considered necessary in engineering terms; and

· San Lung Tsuen is located at the centre of the catchment area, and therefore is the most preferable site. The connecting upstream gravity sewers collecting sewage directly from village houses to the pumping station can be made as shallow as possible.

Two sites for the San Lung Tsuen SPS had been proposed by DSD for initial engineering consideration (Figure 5.1). However, owing to the fact that the land is a private site and there is currently a new building development under construction, this proposal for alternative site had been discarded. No other vacant site can be found in the nearby area. The current site is selected in accordance with the following justifications:

· The selected site is large enough to accommodate the pumping station and is located at the centre of the catchment area;

· The site is free from major underground utilities (rediversion of utilities will cause inconvenience to the villager);

· The pumping station (P4) will be located behind a public toilet and next to an existing electricity transformer station. Screening by existing structures is anticipated;

· All construction equipment and construction vehicles will be parked outside the village. This parking area will be more than 150-200m away from the pumping station;

· Owing to the narrow access road, sewer will only be laid in a small section. Small-scale hand-digging method will be applied to lay the sewer within the village. Care will be taken to avoid any potential damage to any Declared Monument;

· Prefabrication works can be used to reduce the construction work of pumping station;

· Landscaping/planting or textual improvement have been proposed to reduce the visual impact;

· For works located closed to temple and ancestral halls, a condition survey will be carried out in advance of works and a report compiled and submitted to AMO for approval; and

· As discussed in later sections, there will be no adverse cultural heritage and other environmental impacts on the current site selection.

The correspondences are listed in Appendix 5.2 for reference.

AAB	Antiquities Advisory Board
AMO	Antiquities and Monuments Office
ANLs	Acceptable Noise Levels
APCO	Air Pollution Control Ordinance
AQOs	Air Quality Objectives
Arup	Ove Arup and Partners
ASR	Air Sensitive Receptors
BNLs	Base Noise Levels
BOD5	5 day Biochemical Oxygen Demand
CNP	Construction Noise Permit
COD	Chemical Oxygen Demand
dB	Decibels
DEP	Director of Environmental Protection
DO	Dissolved Oxygen
DPWCZ	Deep Bay Water Control Zone
DSD	Drainage Services Department
EIA	Environmental Impact Assessment
EIAO	Environmental Impact Assessment Ordinance
EM&A	Environmental Monitoring and Audit
EP	Environmental Permit
EPD	Environmental Protection Department
FMC	Fill Management Committee
HKPSG	Hong Kong Planning Standards and Guidelines
LR	Physical Landscape Resources
LCA	Landscape Character Areas
NWWCZ	North Western Water Control Zone
NCO	Noise Control Ordinance
NSRs	Noise Sensitive Receivers
OZP	Outline Zoning Plan
PCW	Prescribed Construction Work
PME	Powered Mechanical Equipment
ProPECC PN	Practice Note for Professional Person
PRCRG	Peoples’ Republic of China Regulations and Guidelines
RPCC	Recommended Pollution Control Clauses for Construction Contracts
RSP	Respirable Suspended Particulates
SPME	Specified Powered Mechanical Equipment
SPS	Sewage Pumping Station
SWL	Sound Power Level
SWSTW	San Wai Sewage Treatment Works
TIN	Total Inorganic Nitrogen
TMs	Technical Memoranda
TM-CW	Technical Memorandum on Noise from Construction Work other than Percussive Piling
TM-DA	Technical Memorandum on Noise from Construction Work in Designated Areas
TM-PP	Technical Memorandum on Noise from Percussive Piling
TM-EIAO	Technical Memorandum on Environmental Impact Assessment Process
TM-IND	Technical Memorandum for the Assessment of Noise from Places other than Domestic Premises, Public Places or Construction Sites
TM-Water	Technical Memorandum on Standards for Effluents Discharged into Drainage and Sewerage Systems, Inland and Coastal Waters
TOC	Total Organic Carbon
TSP	Total Suspended Particulates
VSR	Visually Sensitive Receivers
WCZ	Water Control Zone
WDO	Waste Disposal Ordinance
WPCO	Water Pollution Control Ordinance
WQI	Water Quality Index
WQO	Water Quality Objectives
WSRs	Water Sensitive Receivers
YLEPS	Yuen Long Effluent Pumping Station
YLSTW	Yuen Long Sewage Treatment Works
YLKTSSD	Yuen Long and Kam Tin Sewerage and Sewage Disposal

1.5 Environmental Needs and Benefits

3.1.1 Statutory Requirements for Stage 2 Works

3.1.2 Scope for Stage 2 Works

5.1.1 Conforming Scheme of 2A-1T (Figure 1.4 & Figures 1.4.1 to 1.4.6)

5.1.2 Alternative Scheme of 2A-1T (Figure 1.1 & Figures 1.1.5 to 1.1.9)

5.2.1 Ecological and Fishery Impacts

5.2.2 Landscape Impact

Impacts on Landscape Resources

Impacts on Landscape Character

5.2.3 Visual Impact

Impacts on Visual Sensitive Receivers

5.2.4 Cultural Heritage Impact

5.2.5 Noise Impacts

5.2.6 Air Quality Impacts

5.2.7 Waste Management and Land Contamination

5.2.8 Resumption of Private Buildings/Lands

5.2.9 Compatibility with Future Land Use

5.2.10 Accessibility

5.2.11 Engineering

5.4.1 Alternative Sites for YLEPS (Designated Element)

5.4.2 Alternative Sites for San Lung Tsuen SPS (Non-Designated Element)