ERM-Hong Kong, Ltd (ERM) has been commissioned by the Drainage Services Department (DSD) to conduct the Yuen Long and Kam Tin Sewerage and Sewage Disposal Stage 1 Sewers, Rising Mains and Ancillary Pumping Stations (the Project) - Environmental Impact Assessment and Traffic Impact Assessment Studies (the Assignment).
The Assignment requires the undertaking of an Environmental Impact Assessment Study for the Designated Elements and Potentially Designated Elements of the Project (EIA(DE) Study). Works items classified as Designated Elements of the Project (under Schedule 2, Part I of the Environmental Impact Assessment Ordinance (EIAO)) and works items considered to be Potentially Designated Elements are described in Section 1.2.
The proposed works were recommended under the “Review of Yuen Long and Kam Tin Sewerage and Sewage Treatment Requirements” (SMP Review) commissioned by the Environmental Protection Department (EPD). The SMP Review reconsidered the proposals made in the “Yuen Long and Kam Tin SMP” (completed in 1992) in the light of changes in the catchment. The SMP Review included an environmental review of the proposed alignment of the works and identified no insurmountable environmental impacts. The alignment of the works is mostly based on that described in the original SMP study, although some changes have been made as the design has progressed. The alignment, having taken into account site constraints and engineering requirements, follows the existing roads or proposed new roads for the majority of its length. The pumping stations have been sited based on engineering requirements for the sewerage works with due regard to land use and environmental impacts. If the proposed works are not implemented, the area will remain unsewered and the absence of proper sewerage and sewage treatment and disposal facilities would cause untreated sewage to continue to be discharged to watercourses leading to the Deep Bay.
Implementation of the recommendations in the SMP Review will include the construction of about 45km trunk sewers, rising mains, and sewage pumping stations (SPS) to collect and convey sewage flows in the North West New Territories to the Yuen Long or San Wai Sewage Treatment Works (STW). The effluent will be treated before ultimate marine disposal through the Urmston Road outfall. Not included in the scope of this EIA is the expansion of the facilities at the existing Ha Tsuen SPS and San Wai STW. This development is the subject of a separate EIA study.
This EIA Study addresses the impacts caused by the Stage 1 works on sewers, rising mains and ancillary pumping stations (PWP Item No 215DS). Two further EIA Studies will be commissioned to address respectively the works at the existing Ha Tsuen SPS and San Wai STW, and Stage 2 of the Project.
The overall Study Area for this Assignment is presented in Figure 1.2a. The scope of this EIA Study includes the Designated and Potentially Designated Elements of the Project which includes the construction and operation of a trunk sewerage system with five sections of sewers/rising mains and seven associated pumping stations. These elements are listed in Table 1.2a. and are shown in Figure 1.2b.
Table 1.2a Designated and Potentially Designated Elements of the Project
|
Item |
Locations |
|
Designated
Elements - The following items are regarded as Designated Projects by virtue
of Item Q1 of the Schedule 2, Part I of the EIAO. |
|
|
S4 |
Sewers/rising mains between
Kam Tin sewage pumping station (KTPS) and Nam Sang Wai sewage pumping station
(NSWPS) [2.8km]. |
|
S6 |
Sewers/rising mains from
NSWPS to Yuen Long sewage treatment works (YLSTWs) [3km]. |
|
Potentially
Designated Elements - The following items could potentially become Designated
Projects in the context of the ongoing “Planning and Development Study on
North West New Territories”. |
|
|
S1 |
Sewers/rising mains along
Kam Tin Main Drainage Channel (MDC) from Shui Tsan Tin sewage pumping station
(STTPS) to Ng Ka Tsuen sewage pumping station (NKTPS) [1.8km]. (by virtue of Item
Q1 of the Schedule 2, Part 1 of the EIAO) |
|
S2 |
Sewers/rising mains along
Kam Tin MDC from Pang Ka Tsuen sewage pumping station (PKTPS) to KTPS
[1.3km]. (by virtue of Item Q1 of the Schedule 2, Part 1 of the EIAO) |
|
S5 |
Branch sewers/rising mains from
Sha Po sewage pumping station (SPPS) to item S4 [1.2km]. (by virtue of Item
Q1 of the Schedule 2, Part 1 of the EIAO) |
|
P1 |
Kam Tin Sewage Pumping
Station (KTPS) [Design Flow = 37,409 m3 day-1]. (by virtue of Item F3 (b) of the Schedule
2, Part 1 of the EIAO) |
|
P2 |
Sha Po Sewage Pumping
Station (SPPS) [Design Flow = 21,944 m3 day-1]. (by virtue of Item F3 (b) of the
Schedule 2, Part 1 of the EIAO) |
|
P4 |
Shui Tsan Tin Sewage
Pumping Station (STTPS) [Design Flow = 2,712 m3 day-1].
(by virtue of Item F3 (b) of the Schedule 2, Part 1 of the EIAO) |
|
P5 |
Ng Ka Tsuen Sewage Pumping
Station (NKTPS) [Design Flow = 27,842 m3 day-1]. (by
virtue of Item F3 (b) of the Schedule 2, Part 1 of the EIAO) |
|
The
following are classified as potentially designated elements of the Project
for the sake of assessment under this Study in the light of possible changing
circumstances of the ongoing planning for the areas. |
|
|
P3 |
Nam Sang Wai Sewage Pumping Station (NSWPS) [Design Flow = 68,702 m3
day-1]. |
|
P6 |
Pang Ka Tsuen Sewage Pumping Station (PKTPS) [also known as Kam Tin
San Tsuen Sewage Pumping Station] [Design Flow = 1,792 m3 day-1]. |
|
P7 |
Leung Uk Tsuen
Sewage Pumping Station (LUTPS) [Design Flow = 1,360m3 day-1]. |
The total length of sewers/rising mains to be constructed for this phase of the project is approximately 10km. The diameters of the proposed sewers and rising mains range from about 225 mm to 1,650 mm. The expansion of sewers/rising mains networks under the Stage 1 works will deliver domestic sewage for treatment at the Yuen Long Sewage Treatment Works and so extend the coverage of the sewage collection system. The works will allow 33% more sewage flow to be collected from the Kam Tin Catchment, rather than being discharged to inland waters without any treatment.
The construction works will be carried out in three packages, as presented in Table 1.2b.
Table 1.2b Construction Period
|
Package |
Construction Period |
|
1A-1T
Kam Tin Trunk Sewerage Phase 1 |
Aug
2003 - Feb 2006 |
|
·
(S2)
Sewers/rising mains along Kam Tin MDC from PKTPS to KTPS. |
|
|
·
(S4)
Sewers/rising mains between KTPS and NSWPS; |
|
|
·
(S5) Branch sewers/rising
mains from SPPS to item S4. |
|
|
·
Part of (S3) Sewers/rising mains in the Kam Tin/Shek Kong areas
upstream of Kam Tin Sewage Pumping Station |
|
|
·
(S7) Sewers in Au Tau Area |
|
|
·
(S6)
Sewers/rising mains from NSWPS to YLSTWs; |
|
|
·
(P1) KTPS; |
|
|
·
(P2) SPPS; |
|
|
·
(P3) NSWPS; |
|
|
1B-1T Kam Tin Trunk Sewerage Phase 2 |
Jun 2004 - Nov 2006 |
|
·
(S1)
Sewers/rising mains along Kam Tin MDC from STTPS to NKTPS. |
|
|
·
Part of (S3) Sewers/rising mains in the Kam Tin/Shek Kong areas upstream
of Kam Tin Sewage Pumping Station |
|
|
·
(P4) STTPS; |
|
|
·
(P5) NKTPS; |
|
|
·
(P6) PKTPS; |
|
|
·
(P7) LUTPS; |
|
|
1A-2T Sewers/Rising Mains between Ha Tsuen SPS and
San Wai STW |
Aug 2004 - Feb 2008 |
|
·
(S8) Sewers/Rising Mains between Ha Tsuen SPS and San Wai STW |
|
The construction works for the Designated Elements and Potentially Designated Elements (and hence the scope of this EIA Study) will fall under packages 1A-1T and 1B-1T (Items in bold) (See Figure 1.2a).
The construction of pumping stations varies in duration from 12 to 24 months and will be undertaken simultaneously. The construction time for the sewers and rising mains varies from 24 to 36 months and the Temporary Traffic Measures recommended by Traffic Impact Assessment (TIA) Study will also have implications for the construction programme. The normal working hours are from 7am to 7 pm, Monday to Saturday (except Public Holidays). No construction works outside the normal working hours are envisaged.
The Project is located in the Sub-urban area of Yuen Long and Kam Tin. According to the definitions described in the Study Brief, the study areas in relation to specific environmental aspects are as shown graphically in Figure 1.2b.
Due to the rapid development in the NWNT area, a large number of development projects will be undertaken simultaneously, creating the potential for cumulative impacts during construction. Table 1.4a lists the concurrent projects in the NWNT which have the potential to cause cumulative impacts.
Table 1.4a Concurrent Projects with the Designated and Potentially Designated Elements
|
|
Concurrent Project |
Scheduled Construction
Period Start Complete |
Overlapping Months with
this Project |
Potential to Cause
Cumulative Impacts |
|
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|
215DS - Yuen Long and Kam Tin Sewerage and Sewage Disposal Stage
(Non-Designated Element of this Project) |
Aug 2003 |
Feb 2008 |
40 |
|
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|
70CD - Yuen Long Bypass Floodway |
Nov 2002 |
Nov 2005 |
28 |
|
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|
215DS - Yuen Long and Kam Tin Sewerage and Sewage Disposal Stage 2 · Package 2A-1T -
Yuen Long STW Effluent Pipeline · Package 2A-2T -
Ngau Tam Mei/San Tin Trunk Sewerage Phase 1 & Package 2B-1T - Ngau Tam
Mei/San Tin Trunk Sewerage Phase 2 · Package 2A-3T -
Lau Fau Shan/Mong Tseng Trunk Sewerage & Package 2B-2T - Yuen Long South
Branch Sewers |
May 2005 late 2005 late 2005 |
Aug 2007 late 2008 late 2007 |
19 ~12 ~12 |
û û |
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92CD - Yuen Long, Kam Tin, Ngau Tam Mei and Tin Shui Wai Drainage
Improvement, Stage I |
Dec 2001 |
Jun 2006 |
35 |
|
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|
6246 TH - Kam Tin Bypass |
Jun 2001 |
Dec 2003 |
4 |
|
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|
702TH - Improvement to Kam Tin Road Stage II |
As advised by HyD, programme to be reviewed in 2003 |
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Notes: = possible û = unlikely |
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