4.1 The
general water quality of the beaches in the Southern
District met the WQO for bathing water in 2001. About
75% of the beaches in the district were ranked "Good"
in 2001 (Figure 4.1). They are all situated on the south
of the Hong Kong Island, where new sewers have been
provided to serve the domestic buildings in recent years
(Figure 4.2).
4.2 These
"Good" beaches were also less susceptible
to the effect of rainfall and had less fluctuating
water quality as reflected by their good or fair weekly
grading (Figure 4.3). Among them, South Bay had the
best water quality with an annual geometric mean E.
coli level of 5 per 100mL in 2001.
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| Figure 4.3 Distribution
of the weekly grading at the beaches on Hong Kong
Island during the bathing season |
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| Newly
built sewage pumping facility at Deep Water Bay |
4.3 Although
Deep Water Bay Beach had good water quality, it was
at the lower range of the "Good" rank in
2001. It was more susceptible to the effect of rainfall
since the wastewater from the beach facilities was
treated by septic tank and soakaway pit systems. However,
since August 2001, the wastewater from the beach facilities
has been diverted to a public sewer, it is expected
that the water quality of the Deep Water Bay Beach
will further improve.
4.4 The water
quality of the beaches on the east of the Hong Kong
Island, viz. Shek O, Rocky Bay and Big Wave Bay was
not as good as the other beaches on the south. They
were ranked "Fair" in 2001. The hinterland
of Big Wave Bay is unsewered while those of Rocky
Bay and Shek O are served by a combined drainage system
and are partially sewered. During heavy rain, pollutants
are flushed out from the surface channels and the
septic tank/soakaway systems. These three beaches
are highly susceptible to the rainfall effect, resulting
in fluctuating water quality during the bathing season
(Figure 4.3).
4.5 The water
quality of these beaches is also affected by the polluted
marine water from the Tathong Channel, which is affected
by the polluted flow from the Victoria Habour, and
the discharges from the two submarine outfalls of
the Chai Wan and the Tseung Kwan O Preliminary Treatment
Works respectively. EPD's marine monitoring results
indicate that the water quality of the northern Tathong
Channel is poor with average E. coli levels
ranging from 103 to 104 per
100mL. However, the commissioning of the first stage
of the Harbour Area Treatment Scheme in November /
December 2001 has removed these pollution sources
and water quality in the area should improve as a
result.
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Sewage
Treatment Works at Stonecutters Island (HATS
Stage 1)
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