| Annual
Ranking System
The current
Beach
Monitoring Programme has
been designed to assess the
bacteriological water quality
of bathing beaches and the compliance
with the WQO. The beach monitoring
data would also provide information
on beach water quality trends
for the authority to decide
on whether a beach should be
opened or closed for swimming.
The monitoring of beach water
quality is based on the measurement
of E. coli
density which is the microbiological
parameter stipulated in the
WQO and is also an internationally
acceptable indicator.
The
establishment of an annual ranking
system facilitates the interpretation
of long term water quality changes
at different beaches. The rank
of a beach is determined by
calculating the annual geometric
mean E. coli
density with all the data collected
during the bathing season from
1 March to 31 October.
Under
the annual ranking system, beaches
are classified according to
their annual geometric mean
E. coli
densities in the beach water.
There are four categories for
the annual ranking of beaches,
viz. "Good", "Fair",
"Poor" and "Very
Poor". The water quality
of beaches in the first two
categories i.e. "Good"
and "Fair", meets
the WQO for bathing beaches.
Beaches having annual geometric
mean E. coli
densities greater than 610 per
100mL are ranked "Very
Poor" and the beach
management authority would
consider closing these beaches
for the next bathing season.
| Annual
ranking system for beaches
|
| Rank |
E.
coli count per
100mL* |
Minor
illness rate**
(Cases per 1000 swimmers) |
WQO
Compliance |
|
Good
Fair
|
< 24
25 - 180
|
undetectable
< 10
|
Complied
|
|
Poor
Very Poor
|
181
- 610
> 610
|
11
to 15
>15
|
Not complied |
*
Geometric mean E. coli
count calculated based on all
the data collected during the
bathing season.
** Gastrointestinal and skin
complaints
|
|