2.
Description
of THE PROJECT
2.1
Location of Designated Project and Existing Environment
2.1.1
Secondary drainage channel KT13
(hereinafter also referred as KT13) is in the vicinity of a recognized egretry,
the Ho Pui Egretry. The site is located between two villages, Ma On Kong and Ho
Pui in southern Kam Tin in
2.2
Secondary Drainage Channel KT13
Sections A and B
2.2.1 The Yuen Long, Kam Tin, Ngau Tam Mei and Tin Shui Wai Drainage Master Plan Study (YLDMP), which was completed in December 1998, recommended the implementation of a number of secondary drainage channels at Kam Tin and Ngau Tam Mei areas to alleviate local flooding. The Study also defined the extent of the 10 proposed channels for subsequent implementation under the captioned project.
2.2.2 KT13 is one of the proposed secondary drainage channels proposed under this project to alleviate flooding at Ma On Kong area that occurs due to the overflows for the Ho Pui and Tai Lam Chung Catchwaters. In order to protect the Ho Pui Egretry, which was zoned as Conservation Area (CA) at middle section of the existing stream-course, and the nearby wetland areas, the YLDMP recommended not to train the middle section as the residual flooding after completion of the proposed drainage works is tolerable without affecting the village houses. Over-bank flow would still occur along the left bank of the stream course at the middle section, where there were ponds and a temporary structure for poultry but the extent would be less.
2.2.3 In May 2000, site visits confirmed there were no changes to the site conditions identified in the YLDMP. By late 2005, however, re-visits to the site revealed all of the ponds along the left bank, which constitute the former wetland, (looking from downstream to upstream) of the stream course had been filled by parties unconnected with this project. The filling of those ponds would obstruct the overland flow, reducing the former flood plain leading to higher water levels but are unlikely to increase the flooding hazard to the adjacent village houses on the right bank (looking from downstream to upstream) as the right bank is high. Hydraulic modeling results confirmed that, without training the middle section, the 50 –year return period flow could be retained within the proposed trained sections A and B. Over-bank flow still occur at the middle section but with a lesser extent.
2.2.4 In order to improve the hydraulic performance of the streamcourse, the downstream section (Section A) of the streamcourse is widened and deepened to a trapezoidal channel with 5 m wide gabion base and banks, and depth of 3 m. The upstream section (Section B) is also trained to a trapezoidal channel with 5 m wide gabion base and banks with a constant depth of 2 m. Figures 2.2A and 2.2B shows the locations of Sections A and B.
Introduction of Bypass Culvert
2.2.5
On
2.2.6
A topographical survey was
carried out on the filled areas on the
2.2.7 A bypass culvert passing through the filled area to divert most of the flood water from the up stream section to the downstream section during high water flow was proposed. The 50-year return period flows can be contained in the trained upstream and down stream sections, the bypass culvert and the untouched middle section without over-bank flow. The bypass culvert design will maintain a continuous water flow of about 250 mm to 300 mm in depth which is the same as the existing dry weather flow condition at the untouched portion of the stream to minimize the ecological impact of the proposed drainage improvement works. The bypass culvert alignment, however, partly encroach into an area zoned as Conservation Area (CA).
2.2.8
Ma On Kong and Ho Pui areas are
included on the Kam Tin South Outline Zoning Plan (OZP) No. S/YL-KTS/9. Three
plots of land clustering at Ho Pui that used to cover an egretry are also zoned
“CA”. By late 2005, however, all of the ponds that constitute the left bank of
the existing stream had been filled. On 10 April, 30 April, 22 May, 26 May, 22
June, 26 June, 1 July and
2.2.9 The Explanation Statement of the OZP No. S/YL-KTS/9 gives the planning intention of the CA, which is to retain the existing natural characteristics of the area. These areas constitute ecological landscapes and topographical features in rural areas, and may be used to separate sensitive natural systems from the adverse effects of active developments.
2.2.10 A concrete bypass culvert will be built for the middle section of Ma On Kong streamcourse with the maintenance access to be formed above the bypass culvert. The alignment of the proposed bypass culvert, the associated access road, gates are shown on Figures 2.2A and 2.2B. The bypass culvert is a twin cell each 3.7 m wide x 2.2 m high (and 2.5 m wide x 3.2 m high) box culvert. With the bypass culvert, the flow in the middle section of Ma On Kong streamcourse can be controlled so that there will be no overbank flow during a 1 in 50 years storm, while maintaining existing normal dry weather flow of about 250 mm to 300 mm water depth in the unmodified middle section of the KT13 stream to ensure protection of egretry and associated habitat. The bypass culvert will encroach about 420 m2 of the CA zone.
2.2.11 The introduction of this culvert can prevent the need to carry out further drainage work in the area. The culvert will be constructed by conventional open cut method. The current design is to fill and cover the top of the culvert for use as DSD's maintenance access road. Grassed cellular concrete paving will be provided for section of the maintenance access of the bypass culvert (within the CA zone) to create a more natural feature, which can integrate with the channel design. A small section of about 25 m of the existing stream (a meander) would inevitably be affected. The affected stream portion will be reconstructed using gabion banks with natural substrates similar to original materials for the stream bed.
2.2.12 With the widening and deepening of both the upstream and downstream sections and a bypass culvert for the middle section, the Ma On Kong streamcourse will have adequate flow capacities to convey the maximum predicted flows within bank.
2.2.13 In summary, the various components of the proposed KT13 channel are shown below.
|
Section |
Type |
Approximate
Length |
Approximate
Width and Depth |
Chainages |
|
Section A |
Trapezoidal channel with gabion
bank and bed |
400 m |
5m x 3 m |
A CH 0 – A CH 401 |
|
Bypass Culvert |
Twin cells concrete box culvert |
400 m |
3.7 m x 2.2 m |
BC CH 0 – BC CH 400 |
|
Section B |
Trapezoidal channel with gabion
bank and bed |
300 m |
5 m x 2 m |
B CH 0 – B CH 301 |
|
Various locations |
Ancillary infrastructure (vehicular
/ pedestrian crossing, pipe crossing, access track, maintenance access / footpath) |
-- |
-- |
At various locations |
Note: The departmental maintenance
responsibilities of the completed channel as well as unchannelised stream
course including meanders will follow the schedule of responsibilities as
stipulated in Appendix A of ETWB TCW No. 14/2004 – Maintenance of Stormwater
Drainage Systems and Natural Watercourse.
In general, DSD will be responsible for the maintenance of the proposed
channel, box culvert, to be modified meander, pipe crossings and maintenance
access.
2.3
Justifications, Needs and Benefits of the Project
Justifications of the Project
2.3.1 In accordance with the findings of the YLDMP, the proposed Project is expected to contribute to the relief of the present drainage problems that have repeatedly led to severe flooding in the study area. With the implementation of the Project, the defence of the well being and properties of local residents against flood risks can be much enhanced. In particular, the YLDMP identified that secondary channels in Tin Shui Wai, Kam Tin and Ngau Tam Mei areas are required:
(i) to drain areas where the existing secondary drainage is insufficient;
(ii) to solve known flooding problems;
(iii) to deal with catchwater overflows; or
(iv) to provide infrastructure for future development where applicable.
2.3.2 The justification of secondary drainage channel KT13, the subject of this EIA Report, and other works elements of the Project was addressed in the Preliminary Project Feasibility Study (PPFS) Report [0023/REP/7/Issue 5 – March 1998] as well as the Environmental Review Report [0023/ER/Issue 2 – February 1998] for this Project. Both reports were endorsed in April 1998.
2.3.3 In summary, the justification of the project (Here it refers to the Stage 1 and Stage 2 works on the whole) and the consequence of not proceeding are given in the following sections:
a) Justification
for Project :
The
Yuen Long, Kam Tin, Ngau Tam Mei & Tin Shui Wai catchments are served by
existing drainage systems. However, rapid urbanization in the areas has
resulted in a higher runoff ratio and the existing systems are insufficient to
provide the required protection standard so that frequent flooding occurs in
the area during heavy rainfall. Extensive training of the primary channels is
being undertaken as recommended in the Territorial Land Drainage and Flood
Control Strategy Study – Phase II (TELADFLOCOSS 2) which was issued in August
1993. Also as recommended in TELADFLOCOSS 2, the Land Drainage Division of
Drainage Services Department commissioned the YLDMP Study to investigate and
recommend measures to resolve secondary and local stormwater drainage problems
in the study area. However during the course of the YLDMP Study it was also necessary
to model the primary channels as the drainage system had to be considered as a
whole. The following drainage problems were revealed in the YLDMP:
i) part
of the primary drainage channels in Tin Shui Wai proved unable to provide the
required flood protection standard stipulated in the Stormwater Drainage Manual
which was published after the TELADFLOCOSS 2 study;
ii) some
of the areas were noted to be flood-prone because of insufficient or
under-sized secondary/local channels - this is particularly important for areas
designated for development;
iii) the
Yuen Long town and Hung Shui Kiu urban drainage system is under-sized in
places.
Mitigation
measures were recommended in the YLDMP Study to solve these drainage problems.
As the primary channels are in place in Yuen Long, Kam Tin and Ngau Tam Mei, it
is now appropriate to upgrade the local and secondary drainage systems in the
area to resolve the local flooding problems within the study area.
b) Consequences
of Not Proceeding :
Two
consequences of not proceeding with the project are identified as follows:
i) Flooding
will persist in the flood-prone areas in Yuen Long, Kam Tin, Ngau Tam Mei &
Tin Shui Wai identified in the DMP Study.
ii) Development
of the study area will be hindered.
Local
areas will still be vulnerable to flooding during heavy rainfall even after
completion of training of the primary channels because of deficiencies in the
secondary and local drainage systems. Moreover, urbanisation and changes of
land use will increase runoff and thus the flooding risk. It is therefore clear
that not proceeding with this project will leave residents exposed to
increasing and unacceptable flooding risk and will hinder development of the
NWNT.
c) Previous
Studies (identifying need) and Policy Acceptance :
The
fore-runner of this project was initiated under a previous consultancy study
entitled “Territorial Land Drainage and Flood Control Strategy Study - Phase
II” (TELADFLOCOSS 2) which was conducted for Drainage Services Department to
address the flooding problems in the North-Western and
Training
of the primary channels in Tin Shui Wai is complete and training of the primary
channels in Yuen Long, Kam Tin and Ngau Tam Mei are also complete. In 1996, the
Land Drainage Division of Drainage Services Department commissioned the YLDMP
Study to investigate and recommend measures to resolve secondary and local
stormwater drainage problems in the study area.
Needs and Benefits
of the Project
2.3.4 The main purpose of the Project is to bring relief to present drainage problems that have repeatedly led to severe flooding in the area. The villagers of Ma On Kong and Ho Pui will be benefited from the Project.
2.3.5 The introduction of the bypass culvert would addressed the over bank flow while at the same time avoided the middle portion of the existing stream which is in close proximity to the Ho Pui Egretry. The design would allow normal dry weather flow to continue flowing in this middle section hence preserving the stream habitat next to the Egretry.
2.3.6 The Project would provide opportunity to remove odourous, unsightly and potentially contaminated sediment accumulated in the stream bed from previous livestock waste and domestic discharges. The Project also would remove some fill material that has been dumped in the nearby fishponds. With the use of gabion bank and base as well as the proposed compensatory and screen planting, the associated environmental impacts will be mitigated to an acceptable level.
2.3.7
Overall, the Project would
minimize the ecological impact while reducing the flooding risks to be
villagers.
2.4
Consideration of Alternative Alignments, Channel Lining Options and
Construction Methods
Alternative Alignment
2.4.1 The secondary drainage channel KT13 requires channelization of a stream which supports ecological habitats with conservation value. When planning this DP, the benefits from optimizing hydraulic performance of the proposed channel design, material and alignment, and also the benefits from the preservation of the natural stream habitats and the Ho Pui Egretry for education and enjoyment were both recognized and weighed.
2.4.2 The need and design for the bypass culvert was initiated by the requirement to avoid modification of the middle section of the stream in order to preserve the Ho Pui Egretry and the associated habitats. This bypass culvert is required to provide sufficient hydraulic capacity to prevent over bank flow at this middle section of the stream during storm conditions. Figure 2.3 shows the location of the proposed DP, planned land use within 500m of the proposed works based on the Outline Zoning Plan (OZP) S/YL-KTS/9, existing occupied residential houses, grave sites and shrines, and the location of the Ho Pui Egretry. It should be noted that the Egretry was not occupied in 2005. Details of the status are discussed further in the Ecological Assessment (Chapter 4).
2.4.3 Figure 2.3 also illustrates that the alignment of the proposed bypass culvert is constrained to the east and the southeast by the existing occupied village houses of Ho Pui Village, Ho Pui Egretry and high terrain. To the west and to the north, the alignment is constrained by existing occupied village houses of Ma On Kong, grave sites and high terrain. These constraints severely limit the feasible alignment options for the bypass culvert.
2.4.4 A total of four possible alignment options have been identified. No other possible alignment options can be found given the constraints listed above. The evaluation of the possible alignment options to avoid Ho Pui Egretry and to avoid or minimize interference with the CA zone is considered in Table 2.1, with reference to Figure B1 included in Appendix B.
Evaluation of Alignment Options for Section of Bypass Channel
|
Alignment
Option |
Environmental
Benefits |
Environmental
Dis-benefits |
Other Factors
/ Constraints Considered |
Considerations |
|
1 |
§ Avoids the majority of the CA zone
consisting of woodland and grassland habitats and avoids completely Ho Pui
Egretry § Further away from village area, less
environmental impacts in terms of noise and dust during construction |
§ Partly encroaches the CA zone (grassland
habitat) § Works close to Ho Pui Egretry § Short section of stream near Ho Pui
Egretry affected |
§ Alignment follows existing disturbed land
(filled ponds) § Clearance of village houses is not
required § No graves will be affected § Least resumption of private lots |
This option essentially avoids the Ho Pui Egretry but with a small
encroachment of the CA zone and stream section. On the other hand, it involves
the least land resumption of private lots and no clearance of village houses
is required hence less disturbance to the public. It is further away from the
main village areas hence less environmental nuisance during construction. Compensatory
planting can be used to compensate for the habitat lost. Screen planting of
bamboo can be used to screen disturbance and provide potential breeding sites
for the Egretry. The fenced maintenance access of the bypass culvert could
essentially act as a buffer to restrict access and development (from Ma On
Kong) near the Egretry. As such, when compared to the other alternatives,
this option is considered as the Preferred
Option. |
|
2 |
§ Avoids CA zone § Works further away from Ho Pui Egretry |
§ Cuts across a woodland § Closer to village area, more
environmental impacts in terms of noise and dust during construction |
§ Resumption of occupied village houses
required § Affects a Qing Dynasty grave |
Although the CA zone can be avoided, the alignment will cut
across the woodland, dividing it into 2 fragments. A Qing Dynasty grave will
also be affected. More environmental nuisance is expected during
construction. This option also requires land resumption of private lots and
village houses. It would involve lengthy time for processing with potential
adverse opposition / objection from the affected villagers. As such, this
option is Not Recommended. |
|
3 |
§ Avoid CA zone |
§ Stream section near Ho Pui Egretry will
be affected § Works close to Ho Pui Egretry § Closer to village area, more
environmental impacts in terms of noise and dust during construction |
§ Resumption of occupied village houses
required § Hydraulic structure required where bypass
culvert crosses stream |
A small portion of the CA zone as well as the existing
stream near the Egretry will inevitably be affected. More environmental
nuisance is expected during construction. This option requires land
resumption of private lots and village houses. It would involve lengthy time
for processing with potential adverse opposition / objection from the
affected villagers. As such, this option is Not Recommended. |
|
4 |
§ Avoids CA zone |
§ Stream section near Ho Pui Egretry will
be affected § Stream tributary will be affected § Affects wetland areas in Ho Pui § Closer to village area, more
environmental impacts in terms of noise and dust during construction |
§ Resumption of occupied village houses
required § Several village access roads / tracks
will be affected § Hydraulic structure required where bypass
culvert crosses tributary §
Longer route, more expensive |
Although the CA zone can be avoided, it will inevitably
affect a section of the existing stream near the Egretry. A section of a
tributary will also be affected. Several village access roads in Ho Pui will
be affected, re-provision will be needed both during construction and
operation stages causing inconvenience to the public. More environmental
nuisance is expected during construction. This option also requires land
resumption of private lots and village houses involving lengthy time for
processing with potential adverse opposition / objection from the affected
villagers. This option is therefore Not
Recommended. |
|
5 (‘Do-nothing Scenario’) |
§ Avoids CA zone |
§ Nil |
§ Over bank flow at middle section will
persist during storm conditions |
The village representatives of Ma On Kong and Ho Pui have
specifically requested during the Pat Heung Rural Committee meeting to train
the middle section of the stream to eliminate over bank flow. Potential
adverse opposition / objection is expected if the request of the villagers is
not considered. This ‘Do-nothing scenario’ option is therefore Not Recommended. |
Notes:
Please
refer to Figure B1 in Appendix B for locations of the possible alignments.
A
more detailed evaluation of the possible alignments can be found in Table B1 in
Appendix B.
2.4.5 The factors and constraints referred to in Table 2.1 are presented in further detail in Table B1 included in Appendix B. This re-affirms the selection of the preferred alignment option as Option 1.
Channel Lining Options
2.4.6 Options for channel lining for the banks and base of the channel include natural bed (substrates such as gravel or mud), gabions, concrete or grasscrete. While the hydraulic performance of concrete and grasscrete lined channels are best for smooth flow and easy maintenance, they will remove the ecological value of the land which they occupy. Also, the rate of transport of sediments downstream, whether clean or contaminated, will also increase, resulting in increase in suspended solids and biological oxygen demand (BOD) in the surface drainage water.
2.4.7
Gabions and natural stream beds
offer surfaces that will sustain a bottom community and are better for
retaining sediments and establishment of vegetation on banks. Natural banks are
prone to erosion and subject to scour under rainstorm conditions, especially if
there are bends in the channel alignment. Annual trimming of the bank side
vegetation and removal of excess sediments will be required to ensure
sufficient hydraulic capacity is retained. Gabions however provide a cost
effective means of channel lining which also reduce the rate of sediment loss
from the watercourse banks which would otherwise ultimately reach
2.4.8 The majority of the section of stream with higher ecological value in close proximity to the Conservation Areas and Ho Pui Egretry is to be preserved by construction of the bypass channel as a buried culvert except for a small section which will be reconstructed with gabion banks and natural substrates stream bed. The bypass culvert is proposed to be constructed as a twin cell reinforced concrete box culvert. No weep holes will be provided for the box culvert to prevent ground contamination by backflows under high flow conditions.
Construction Methods
2.4.9
The buried section of the bypass culvert could be constructed
as a cut-and-cover box culvert, or alternatively by trenchless techniques such
as pipe jacking, tunnel boring machine or horizontal drilling. The various trenchless
techniques are not considered practicable for the following reasons:
§
There is only about 1m soil cover for the bypass culvert as
the depth of the culvert is dictated by the invert levels at the upstream and
downstream sections of the channel.
This is inadequate cover for safe operation of jacking or
tunneling. Such shallow cover would
lead to severe ground instability and settlement during construction. Tunnel
excavation at such shallow depth would also cause interference with tree roots.
For a culvert of this size (2 m high), a minimum ground cover of about 6 m would
be required.
§
Ground treatment such as grouting may be necessary to
stabilize the ground. Grouting would generate additional wastewater to be
handled. Furthermore, at such low cover there would be risk of grout loss onto
ground level or into the stream and also of surrounding tree roots.
§
A tunnel alignment at shallow depth would have to avoid the
stream due to constraints on invert levels mentioned above. To avoid the stream
bed, such an alignment would have to pass to the west of the stream requiring a
bend in the alignment within the CA zone. An additional working pit would be
required at this location to accommodate the bend.
§
Access and working space within the works area to accommodate
the working pits is highly restricted. The only readily available access point
which does not require land resumption is from the road to the north.
§
An alternative trenchless construction method, avoiding many
of the constraints above, would be to construct the tunnel at a deeper invert
level, creating an inverted siphon between shafts at each end of the tunnel.
The alignment of such a tunnel could be straight, passing directly beneath the
stream, thus avoiding the need for any intermediate pit. This would avoid any
interference with the CA zone. However, access for construction of the southern
pit would be problematic, potentially requiring greater land resumption to
create an access route from the south. The main disadvantage of this
construction method is that it would create severe maintenance problems
associated with sedimentation within the inverted siphon, exacerbated by the
polluted flows. The operational problems of such a system are considered to
render the inverted siphon option unviable.
§
Land resumption is reduced to an absolute minimum by adopting
the bypass culvert option including the cut-and-cover box culvert which avoids
existing village houses, avoids creating inconvenience to the public and
minimizes the impacts on the CA zone.
§ All tunneling options require specialized skills during construction.
2.4.10 Hence, it is demonstrated that the most viable construction method option for the bypass channel is a box culvert, given the size of the box culvert that is required and the various constraints discussed above.
2.4.11 The box culvert will be constructed by the conventional open-cut method that is commonly used for such works. This generally involves site clearance, excavation, installation of temporary supports, erection of formwork, concreting, backfilling and surface reinstatement. Works will be carried out section by section. Access to the works area will be along a single works corridor accessed from the road to Ma On Kong to the north.
2.4.12
Off-site precast structures are not considered practicable
due to the limited working space available for transporting, handling and
installation. Also, no suitable works area can be identified. On-site in-situ
construction of the structures is therefore considered more suitable.
2.4.13 Additional fill material will be required to match the final formation level of the culvert with existing ground level. A maintenance access will be built above the bypass culvert to facilitate future maintenance by DSD which would unavoidably entail construction works such as provision of tracks, chain link fence, etc.
2.4.14
The gabion lined channels upstream
and downstream of the bypass culvert will be constructed by conventional
methods common to all drainage channel projects in
2.4.15
The construction methods discussed above are all conventional
construction methods in
Proposed Alignment, Channel Linings and Construction Methods
2.4.16 The proposed balanced solution, adopting open gabion lined channels combined with a cut-and-cover box culvert minimizes the environmental impacts on the areas of higher ecological value. This design approach will enable flood waters to be quickly bypassed downstream during rainstorm events. The channelized sections using gabions will convey the dry weather flow less rapidly, retain sediments and allow bank side vegetation to establish, and will retain some ecological value to the land covered by the KT13 project. The bypass culvert in the middle section will convey the peak flows and will also safely provide a continuous compensation flow to the existing natural watercourse. This will sustain the ecological value of the watercourse and provide feeding for the egrets from the adjacent roost.
2.4.17 Given the various site constraints and the requirement to avoid impacting the Ho Pui Egretry and nearby stream course, no other practical or reasonable alternatives are available. The bypass culvert cannot totally avoid the CA zone and a localized encroachment of about 420 m2 of the CA zone consisting of grassland habitat will inevitably be required. This encroachment has been reduced to an absolute minimum in the design taking into account environmental impacts yet without compromising the main objective of the Project to provide relief to present flooding problems in the area.
Summary of Mitigating
Impacts on the Conservation Area with Reference to Annex 16 of the Technical
Memorandum on EIA Process
2.4.18 As stipulated in Annex 16 of the Technical Memorandum on EIA Process, the general policy of mitigating impacts on important habitats in order of priority, are: Avoidance, Minimization and Compensation. This general policy has been followed in the design of the bypass culvert taking into careful consideration impacts on the CA zone, environmental as well as engineering and social implications (see Table 2.1 and Table B.1 of Appendix B).
2.4.19 Detailed surveys and monitoring revealed that the egretry as previously depicted in the CA zone under the Kam Tin South OZP has moved due to clearance of trees in the area. Parts of CA zone are considered not suitable for nesting egrets (currently of grassland habitat). The new egretry locations are noted and presented in the EIA. The design of the bypass culvert has been carefully considered taking into account environmental, engineering and various other constraints. It is considered that it is prudent that the more ecologically sensitive areas such as Ho Pui Egretry and the associated stream habitat nearby should be avoided and protected. These requirements, however, means that a localized encroachment into the CA zone (of grassland habitat) is inevitable. The bypass culvert has been designed such that the land resumption will be minimized as far as practicable and hence the associated ecological impact and encroachment on the CA zone can be kept to an absolute minimum. Mitigation measures and compensation in terms of tree and bamboo plantings have been proposed to ensure the associated environmental impacts will be mitigated to an acceptable level.
2.5
Design and Construction Programme
2.5.1 The construction of the secondary drainage channel KT13 is scheduled to commence in mid 2007 for completion in mid 2010. The construction of the bypass culvert within the CA zone and the modification works of the meander is expected to last for about 6 months and 3 months respectively.
2.5.2 The endorsed environmental mitigation measures will be incorporated in the detailed design of the channel and will be taken into account in formulating the works programme as well as the tender documents.
2.6
Concurrent Projects and Potential Cumulative Impacts
2.6.1 Relevant concurrent drainage projects in the vicinity of the KT13 that could have some form of cumulative environmental impacts with this DP are shown in Table 2.2, which indicates the duration for each project and the likely overlapping period with this project. No projects over 1000 m from this DP or those outside the Kam Tin River Catchment have been included here since there would be minimal cumulative air quality, noise and water quality impacts with those projects. Ecological parameter such as rarity will be assessed over local, regional, territory wide and global context, and any cumulative ecological impacts between Phase 1 and Phase 2 Works will be assessed in detail.
2.6.2 The main potential cumulative impacts from concurrent projects within the vicinity of KT13 will be related to runoff into the watercourses, and potential noise and dust issues where works are carried out within 500 m of each other.
2.6.3 The measures that are prepared in this EIA will aim to minimise potential impacts to these environmental areas and this minimise overall cumulative impacts to the region.
Concurrent Projects
|
Concurrent Project |
Scheduled Construction Period |
Overlapping Months with this Project |
|
|
Start |
Complete |
||
|
KT2 and KT15 – Yuen
Long, Kam Tin, Ngau Tam Mei and Tin Shui Wai Drainage Improvements Stage 1,
Phase 2B – Kam Tin |
early 2007 |
Late 2009 |
Approximately 30 months |
|
KT14 – Yuen Long, Kam
Tin, Ngau Tam Mei and Tin Shui Wai Drainage Improvements Stage 1, Phase 2B –
Kam Tin |
mid 2007 |
early 2010 |
approximately |
|
KT12 – Yuen Long, Kam
Tin, Ngau Tam Mei and Tin Shui Wai Drainage Improvements Stage 1, Phase 2B –
Kam Tin |
mid 2007 |
end 2009 |
approximately |
2.7 Public Consultation to Date
2.7.1
The process of Continuous
Public Involvement (
Summary of
Continuous Public Involvement
|
Date |
Concerned
Parties |
|
|
§
Pat Heung Rural Committee |
|
|
§
Yuen Long District Council (Town Planning and Development
Committee) |
|
31 May 2002 |
§
Ma On |
|
|
§
Yuen Long District Council (Town Planning and Development
Committee) – consultation by circulation of briefing paper |
|
|
§
Green Groups (WWF |
|
|
§
Pat Heung Rural Committee |
|
|
§
Ma On Kong Village Representatives and villagers §
Ho Pui Village Representatives and villagers |
|
|
§
Ma On Kong Village Representatives and villagers |
2.7.2
During the course of the
Summary of
the Comments and Recommendations received during the Public Consultation
|
Concerned Parties |
Major Comments / Recommendations |
Responses / Outcomes |
|
Pat Heung Rural
Committee |
§
Ho Pui VRs comment that improvement works should not only
concentrate on the upper and lower stream course section and ignore the
middle section. The VRs wished to eliminate over-bank flow along the middle
section of the stream course. The VRs strongly requested the improvement
works to be extended to cover the entire stream course. §
Early commencement of the project. §
Arrangement of the remaining tributaries. §
Connection of existing streams. §
Opening of maintenance access for villager’s use. §
Any works on Shui Tsan Tin village. |
§
One of the reasons was to avoid the Ho Pui Egretry in the
middle section. After further discussion and thorough investigation, a
compromise to provide a by-pass culvert was proposed. §
After the consultation process, the Project needs to follow
relevant statutory requirements. The earliest possible commencement of the
Project would be early 2007. §
Remaining existing tributaries would be preserved, appropriate
design would be provided to maintain water flow. §
Connection to existing stream would be provided to ensure
collection of water from the tributaries. §
Maintenance access is intended for use during maintenance
of the channel and will not be open for public use. §
Shui Tsan Yin village is outside the scope of this Project. |
|
Yuen Long District
Council (Town Planning and Development Committee) |
§
To consult relevant village representatives on the proposed
Project. |
§
Relevant village representatives were consulted and
supported the Project. |
|
Green Groups §
WWF §
Kadoorie Farm & Botanic Garden |
§
Remind that routine maintenance of the by-pass culvert
should not disturb the Ho Pui Egretry. |
§
The maintenance of the culvert would only be undertaken
inside the box culvert below the existing ground level. Disturbance to the
Egretry will be minimal. |
|
Village representatives
and local villagers of: §
Ma On Kong §
Ho Pui |
§
Enquire about the estimated construction fee. §
Enquire about the tendering process, and which contractor is
eligible to bid. §
The affected lots and its area. §
Whether there will be any landscaping works. §
Whether maintenance access could be use by villagers. §
Farms at the upstream regularly discharge polluted water,
resulting in odour nuisance. Enquire whether the project could treat the
odour problem. §
Duration of the construction, possibility of reducing the
duration of construction along Lots 103 & 107 to reduce nuisance. §
Enquire the layout of the reprovision of Ma On Kong Garden. |
§
The estimated construction fee was provided to the VRs. §
Tendering process will be similar to that of typical
government contracts. §
The extent of the affected lots cannot be provided for the
time being, this will be presented in the gazette, Yuen Long District Office
will contact the affected property owner in due course. §
Landscaping works will be provided. §
Maintenance access is intended for use during maintenance
of the channel and will not be open to the public. §
The purpose of the channel is to convey flood water, and
cannot eliminate the source of the odour problem. DSD would liaise with §
To reduce potential nuisance to the residents of Lots 103
& 107 during construction, DSD will specify in the contract that the
construction period for the 100m stretch of the channel near the Lots to be
constructed in 1 year. §
The layout will be similar to the existing one. |
2.7.3 In 2005, the public consultation was completed and the channel design details were finalized. Overall, there are no objections to the final design and the relevant village representatives and Rural Committees supported the proposed Project as it would bring relieve to the flooding in the area.