This section
presents the water quality impact assessment for the construction and
operational phases of the Project.
As the construction works of the Project will be land-based, direct
impacts on water quality will not arise. Nevertheless, the construction of the
tracks would generate surface run-off and wastewater which may cause adverse
water quality impacts if not properly controlled or mitigated. Appropriate mitigation measures and
environmental monitoring and audit, if necessary, are recommended.
The Water Pollution Control Ordinance (WPCO), Environmental Impact
Assessment Ordinance (Cap. 499. S.16) and Annexes 6 and 14 of Technical
Memorandum on Environmental Impact Assessment Process (EIAO-TM) are
applicable to the evaluation of water quality impacts associated with the
Project, whereas Annexes 6 and 14 of the EIAO-TM provide general guidelines and criteria to be used in
assessing water quality issues.
Apart from the above statuary
requirements, the Practice Note for Professional Persons, Construction Site Drainage (ProPECC PN
1/94) and Drainage Plan subject to
comment by the Environmental Protection Department (ProPECC
PN 5/93), issued by EPD, also provides useful guidelines on the management of
construction site drainage and prevention of water pollution associated with
construction activities.
The proposed karting
track is located at Lung Kwu Sheung
Tan which is a rural area with open storage and several plastics recycling
factories located to the west of the site.
There are no watercourses passing through the site. Instead, there is one open drainage
channel located to the west of the site.
In order to evaluate the water
quality impacts resulting from the construction and operation of Project, the
proximity of Water Sensitive Receivers (WSRs) must be
considered. WSRs have been identified in accordance
with HKPSG as well as the EIAO-TM,
which provide criteria for identifying environmental factors influencing
development planning.
There were no water sensitive
receivers identified within 300 m of the Project site boundary.
As aforementioned, minor site
levelling, compacting, track paving works, planting and fence installation are
the major construction works and these would take approximately two
months. Therefore, potential
sources of water quality impacts associated with the construction of the karting tracks comprise:
Potential sources of water
quality impact during operation of the Project include:
·
Surface runoff and drainage; and
·
Domestic sewage effluent produced by
the operators and visitors.
Runoff and drainage from
construction sites may contain considerable loads of suspended solids and
contaminants. Potential sources of
water pollution from site runoff include:
·
Runoff and erosion of exposed bare soil
and earth, drainage channels and stockpiles;
·
Release of cement materials with rain
wash;
·
Wash water from dust suppression sprays
and vehicle wheel washing facilities; and
·
Fuel, oil, and lubricant from
maintenance of construction vehicles and mechanical equipment.
Local and coastal water pollution
will be substantial if the construction site runoff is allowed to drain into
the storm sewer or natural drainage without mitigation. Nevertheless, with the proper
implementation of the good site practices and housekeeping, as to be discussed
in Section 6.6.1, unacceptable water
quality impacts due to construction runoff and drainage are not expected.
On-site construction site
activates may cause water pollution due to the follows:
·
Uncontrolled discharge of debris and
rubbish such as packaging, construction waste and refuse etc; and
·
Spillages of liquid stored on-site,
such as oil, diesel and solvents etc.
The debris and rubbish would
probably enter the open drainage channels and cause blockage. The spillage of liquid may also result
in water quality impacts if they enter storm water drains or open drainage
channels.
However, the effects on water
quality from the construction activities are likely to be minimal, provided
that site boundaries are well maintained and good construction practices are
implemented to ensure that litter, fuel and solvents are managed, stored and
handled properly.
Portable chemical toilets will be
provided for the site workers. A
licensed contractor will be responsible for appropriate disposal and
maintenance of these facilities.
Therefore, no adverse water quality impacts are anticipated.
The main identified source of
potential impact on water quality during the operation phase will be runoff
from the road surfaces. There would
be a vehicle and plant servicing area at where maintenance of karts and petrol
re-fuelling activities would take place.
With this context, the road runoff may contain minimal amounts of oil,
grease and grit that may cause water quality impacts to the receiving water during
rainfall events if uncontrolled.
However, the servicing area and
lubrication bays would be located within paved areas. The drainage serving the servicing area
and petrol re-fuelling point would be connected to storm drains via a petrol
interceptor with peak storm bypass to collect the road runoff contaminants and
to avoid the contaminants entering the watercourses. Therefore, it is considered unlikely to
produce any quantifiable adverse water quality impacts.
Similar to the construction
phase, four portable chemical toilets will be provided for the visitors. A licensed contractor will be
responsible for appropriate disposal and maintenance of these facilities. Therefore, no adverse water quality
impacts are anticipated.
The
following mitigation measures should be implemented during the construction of
the karting track:
·
Provision of perimeter channels to
intercept storm-runoff from outside the site. These shall be constructed in advance of
site formation works and earthworks.
·
Exposed soil surface shall be covered
by tarpaulin as soon as possible to reduce the potential of soil erosion.
·
Open stockpiles of construction
materials on site shall be covered with tarpaulin or similar fabric during
rainstorms.
Debris and rubbish generated
on-site shall be collected, handled and disposed of properly to avoid entering
the nearby stormwater drains and open drainage
channels. All fuel tanks and
storage areas shall be provided with locks and be sited on sealed areas, within
bunds of a capacity equal to 110% of the storage capacity of the largest
tank. Open storm water drains and
culverts near the works area shall be covered to block the entrance of large
debris and refuse.
Sewage
from Workforce
Temporary sanitary facilities,
such as portable chemical toilets, shall be employed at the areas where the
temporary connection is not feasible.
A licensed contractor would be responsible for appropriate disposal and
maintenance of these facilities.
Although no unacceptable water
quality impact is anticipated during the operational phase, the following
measures are recommended:
Surface
Runoff
·
Maintenance of karts should be performed
regularly to avoid leakage of fuel on tracks; and
·
Proper handling of petrol storage tank
to avoid leakage of petrol.
·
Drainage serving the open petrol
re-fuelling point should be connected to storm drains via a petrol interceptor
with peak storm bypass.
·
The servicing areas should be located
within roofed areas and concrete paved area. The drainage in the concrete paved areas
should be connected to foul sewers via a petrol interceptor. Oil leakage or spillage should be
contained and cleaned up immediately.
Waste oil should be collected and stored for recycling or disposal in
accordance with the Waste Disposal
Ordinance.
Four portable chemical toilets
will be provided for the visitors.
A licensed contractor would be responsible for appropriate disposal and
maintenance of these facilities.
No water quality monitoring is
required as no unacceptable water quality impact is expected.
No operational water quality
monitoring is required as no adverse water quality impact is anticipated.
Given the small scale of the
construction works, short duration of construction period and no identified WSRs within the study area, water quality impacts are
negligible and minimal during construction phase of the Project provided that
good site practices and housekeeping are implemented as suggested in Section 6.6.1. Hence, it is considered that no water
quality monitoring would be necessary to carry out during construction phase.
For the operation of karting, the main concern is the water quality impact may
be caused by the servicing and petrol re-fuelling activities. Nevertheless, the surface runoff can be
well controlled by adoption of a proper drainage system with peripheral channel
and petrol interceptor. Addition to
the proper handling of petrol tank and re-fuelling and regular maintenance of
karts, no adverse water quality impacts are anticipated. Therefore, it is suggested that no
operational water quality monitoring would be required.