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Beach
Water Quality Report 2002
Chapter Five
Beaches
in the Tsuen Wan District
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| 5.1 |
There
are eight gazetted beaches
in the Tsuen Wan District.
Tung Wan on Ma Wan and Hoi
Mei Wan had 'Poor' water
quality while the other
six beaches were ranked
'Very Poor' in 2002 (Figure
5.1). Three of the 'Very
Poor' beaches had already
been closed to the public
since mid 1990s. There was
general deterioration of
water quality at all beaches
in the district. |
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| 5.2 |
Tsuen
Wan was the only district where
gazetted beaches did not meet
the WQO for bathing water. The
poor water quality of the Tsuen
Wan beaches is attributed to pollutants
discharged from their unsewered
hinterland, the polluted Sham
Tseng Nullah and the relatively
high bacterial level in the marine
water off the Tsuen Wan coast.
As the beaches are susceptible
to pollution from a number of
potential sources, their water
quality fluctuated widely during
the bathing season (Figure 5.2). |
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| 5.3 |
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Overflow
from septic tanks would
adversely affect the beach
water quality |
The area along
Castle Peak Road from Ting Kau
in the east to Tsing Lung Tau
in the west is still unsewered.
Though new developments along
the Castle Peak Road have private
sewage treatment plants, many
village houses along the road
are still using septic tank
and soakaway pit systems. The
water quality of the beaches
along the Castle Peak Road is
therefore vulnerable to pollution,
particularly during heavy rain,
which may flush out pollutants
from septic tank and soakaway
pit systems and increase polluted
runoffs from the surface drains.
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| 5.4 |
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storm drain also brings
pollutant from the hinterland
to Ting Kau Beach |
The pollution problem at Ting
Kau was exacerbated by local pollution
sources. The Ting Kau Village
has a population of about 1,000
and typical village type houses
with septic tank and soakaway
pit systems for sewage treatment.
The water quality of Ting Kau
is directly affected by watercourses
that run straight into the beach
water. Polluted surface runoffs
and sullage from the village houses
are discharged into these watercourses.
At the downstream of one of the
watercourses, there is a hypochlorite
dosing system operated by LCSD
to disinfect the water before
entering the beach. However, any
malfunctioning of this dosing
system could result in pollution
of the beach water. In order to
ensure that the beach water is
not polluted by this source, this
system is under close scrutiny
by the EPD. |
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| 5.5 |
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The
hypochlorite dosing system
at Ting Kau Beach |
The Anglers' Beach is on the west
of Sham Tseng Nullah and at a
distance of only a few hundred
meters away. The Nullah is heavily
polluted by sewage discharged
from premises along its two banks.
Its polluted flow has direct impact
on the water quality of the beach.
There are also potential local
pollution sources, including the
unsewered villages in the hinterland,
and the private sewage treatment
plants along the Castle Peak Road. |
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| 5.6 |
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Commercial
activities at lower stream
also contributed to the
pollution of Sham Tseng
Nullah |
As an interim measure to alleviate
the pollution problem of the Sham
Tseng Nullah before provision
of sewerage, additional facilities
have been constructed to treat
or collect some of the wastewater
discharged into the nullah. These
include a biological treatment
plant with disinfection which
was commissioned at the end of
2001 to treat the sewage collected
from the Sham Tseng Upper and
Lower Resite Villages, and storage
tanks to collect wastewater from
the Sham Tseng temporary Refuse
Collection Point, public toilet
and the temporary market for tankering
away. |
| 5.7 |
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The
interim sewage treatment
plant at Sham Tseng collects
and treats part of the wastewater
discharged to Sham Tseng
Nullah |
Another biological treatment plant
with disinfection facilities was
constructed and commissioned at
the end of 2001 to treat wastewater
collected from the Yuen Tun Resite
Village in the Tsing Lung Tau
area. The treated effluent is
then directly discharged to sea
via a storm drain. A large population
along the Castle Peak Road is
served by a number of private
sewage treatment plants with disinfection
facilities. Treated effluent from
these plants is discharged directly
to the coastal water. Any malfunctioning
of these sewage treatment plants
could result in severe deterioration
of beach water quality. The EPD
had paid frequent visits to these
facilities to ensure that they
were properly operated and maintained.
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| 5.8 |
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Castle
Peak Road widening work
in progress |
As a long-term solution to improve
the water quality of the whole
area, it has been planned to provide
sewerage along the Castle Peak
Road from Ting Kau to Tsing Lung
Tau (Figure 5.3). Sewage from
the villages in the hinterland
of all beaches will be collected
and conveyed to a new sewage treatment
plant to be built on reclaimed
land in Sham Tseng for treatment.
At this new plant, sewage will
be treated by chemically enhanced
primary treatment with disinfection
prior to discharge to sea via
a submarine outfall. The construction
of the sewage treatment plant
and submarine outfall has commenced
in 2001 and is expected to be
completed around the end of 2003.
However, the laying of the whole
trunk sewer along the Castle Peak
Road is only expected to be completed
around the end of 2005 for connection
with village houses and individual
properties. It is therefore expected
that the removal of the local
pollution sources in the hinterland
will begin to happen after 2006
at the earliest. |
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| 5.9 |
The
poor water quality of the beaches
in the Tsuen Wan District is also
related to the relatively high
bacterial level in the marine
water off the Tsuen Wan coast.
After the full commissioning of
the HATS Stage I at the end of
2001 (Figure 5.4), elevation in
bacterial level had been observed
in the western water. As the daily
treatment capacity of SCISTW has
approximately quadrupled from
0.3 million m3 per
day during partial operation to
1.3 million m3 per
day after full commissioning,
the discharge of such a huge volume
of treated effluent at the western
approaches of the Harbour has
resulted in the elevation of bacterial
level in the marine water there
and imposed an adverse impact
on the water quality of the Tsuen
Wan beaches. A series of studies
on the final level of treatment
and technology to be adopted for
the remaining stages of HATS is
being undertaken. It is envisaged
that when the remaining stages
of HATS are implemented, the water
quality of the marine water and
beaches in the Tsuen Wan District
will significantly improve.
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