The current Beach Monitoring Programme has been designed to assess the 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 Leisure and Cultural Services Department 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)
|Fair||25 - 180||10|
|Poor||181 - 610||11 to 15||Not complied|
|Very Poor||> 610||> 15|
* Geometric mean E. coli count calculated based on all the data collected during the bathing season.
** Gastrointestinal and skin complaints