According to the assessment presented
in Section 6 of the EIA Report for the Project, much of the works would be
confined within existing site boundaries or to developed/disturbed areas of low
ecological value such as along the South Lantau Road. It was anticipated that
provided that good site practices and mitigation measures to minimise impacts
are strictly observed, ecological impacts would be minimal.
The main concern arising from the
Project was vegetation clearance and disturbance within woodland habitat at Pui
O associated with raw water mains
installation. The works area within woodland habitat would amount to
approximately 0.4ha. Within this
woodland habitat, recent surveys found several individuals of two shrub/tree
species of conservation interest namely Pavetta
hongkongensis and Aquilaria sinensis.
Regular site audit of mitigation
measures for good site practice will serve to minimise ecological impacts.
Reinstatement of disturbed areas through replanting of trees and vegetation as
specified in Section 6 of this Manual, will also minimise ecological impacts.
General EM&A requirements
concerning protection of the two species of shrub/trees of conservation
importance are also recommended in this section. However, the details on
arrangements for transplantation will require inclusion at the detailed design
The following mitigation measures were
recommended to minimise ecological impacts
to minimise impacts on vegetation in woodland
All trees should be preserved as far
as possible, especially species of high conservation or amenity value.
Recommendations to be provided in the Tree Survey Report to mitigate impacts on
trees should be followed. Where trees
are to be preserved in-situ, but are likely to be disturbed from works
activities, protective fencing/hoarding should be carefully set up around the
Disturbance of individuals of the
protected shrub species Pavetta
hongkongensis and tree Aquilaria
sinensis of high conservation value should be avoided. A buffer to the
dripline of each plant
and no less than of at least 1m radius
should be demarcated to prohibit disturbance.
Where loss of this species would be unavoidable, it is recommended that
these plants may be transplanted to safe locations within the same habitat.
Exact receptor sites should be determined by the horticulturist/ecologist on
site at the time of the transplantation so that generally plants are moved a sma ll a
distance as possible to clear the works areas.
Specifications for transplantation should be included at the design
Mitigation to minimise impacts from construction
Trench excavation works for the raw
water mains should be carried out in the dry season, as far as
practicable. Site runoff should be directed towards regularly cleaned and
maintained silt traps and oil/grease separators to minimise the risk of
sedimentation and pollution of river water. The silt and oil/grease separators
should be appropriately designed for the local drainage and ground conditions
(refer to Section 4 – Water Quality).
to minimise general disturbance to wildlife
Noise mitigation measures through the
use of quiet construction plant should be implemented to minimise disturbance
to habitats adjacent to the works areas.
General good site practice
Place equipment or
stockpile in designated works areas and access routes selected on existing
disturbed land to minimise disturbance to natural habitats.
activities should be restricted to works areas that should be clearly
demarcated. The work
areas should be reinstated after completion of the works.
should be provided to collect general refuse and construction wastes. The
wastes should be disposed of timely and properly off-site.
drainage arrangements should include sediment and oil traps to collect and
control construction site run-off.
burning on works sites is illegal, and should be strictly prohibited. Stove
fires on works sites should also not be allowed. Temporary fire fighting
equipment should be provided particularly in woodland areas.
Re-vegetation to reinstate works areas
As far as
possible compensatory planting should use native plants of the same species
that occur in the adjacent woodland habitat and have flowers/fruits attractive
Environmental Monitoring and Audit
The proper implementation of
mitigation measures recommended above should be routinely audited during the
methodology detailing the treatment of Pavetta
hongkongensis and Aquilaria sinensis
within the works areas in woodland should be formulated during the detailed
At the detailed design stage,
individuals requiring transplantation and individuals requiring protection
should be identified. Details should also include transplantation methodology
and measures for the individuals to be protected ‘in-situ’. Survey work and
reporting should be carried out by a suitably qualified ecologist/
horticulturist appointed by the Project Proponent. Suitable receptor sites
should also be identified and prepared by the ecologist/ horticulturist prior
Following identification of individuals
to be transplanted, transplantation procedures should be completed in advance
of commencement of construction works.
The transplantation should be carried out by a suitably qualified
ecologist/ horticulturist appointed by the Project Proponent. Measures to
protect plants ‘in-situ’ should also be implemented prior to commencement of
Following any transplantation of Pavetta hongkongensis and Aquilaria sinensis individuals, regular
monitoring of the trees and seedlings should be conducted to check on the
health and condition of the plants. It is recommended that monitoring should
cover the 12-month period following transplantation. Monitoring should be conducted at least twice a month for the
first four months after transplantation, and once a month for the remaining
eight months. Monitoring should be conducted by a suitably qualified
ecologist/horticulturalist appointed by the Project Proponent. If audit records
indicate that the transplanted plants are not establishing properly, the
Landscape Architect should recommend and undertake measures to rescue the