Beach Water Quality in Hong Kong for 2001
(ACE Paper 3/2002)
For information
INTRODUCTION
The purpose of this paper is to brief Members on the water quality of gazetted beaches in Hong Kong in 2001 and the arrangement for monitoring the water quality of the three beaches which are opened all year round.
BACKGROUND
2. The Environmental Protection Department (EPD) has implemented a monitoring programme to assess the water quality of 41 gazetted beaches in Hong Kong and publishes each year a comprehensive report on beach water quality. The 2001 annual report is now ready and attached with this paper.
STATUS OF BEACH WATER QUALITY
3. The beach water quality is assessed through a ranking system which links the water quality of a beach with swimming-associated health risks. According to this system, beaches are ranked as "Good", "Fair", "Poor" or "Very Poor". Only those in the ranks of "Good" and "Fair" meet the water quality objectives (WQO) for bathing water.
4. The water quality of 34 out of 41 gazetted beaches had met the WQO for bathing water in 2001. The percentage of beaches meeting the WQO has dropped slightly from 85% in 2000 to 83% in 2001. Among the 41 gazetted beaches, 21 are ranked 'Good', 13 'Fair', five 'Poor' and two 'Very Poor' (Figure 1). Compared with 2000, we have one less gazetted beach with "Fair" water quality, and one less gazetted beach with "Poor" water quality while the number of gazetted beaches with "Very Poor" water quality has gone up by two in 2001.
5. The ranking for gazetted beaches in the past ten years is shown in Figure 2. The improving water quality trend observed in the late 1990's had stalled in 2001. The slight drop was due to the abnormally high rainfall in the bathing season of 2001, which exceeded the average annual rainfall by 40%. The heavy rainfall increased polluted surface runoffs and flushed out pollutants from septic tanks and soakaway pit systems in the unsewered hinterlands into the beach areas, causing transient deterioration of beach water quality.
6. Beaches with more fluctuations of water quality are found in the Tsuen Wan District. As the hinterland of these beaches is still unsewered, their water quality is highly susceptible to the effect of rainfall. Apart from the rainfall effect, the water quality of these beaches is also affected by the polluted Sham Tseng Nullah, and to a smaller extent by the polluted marine water around the Rambler Channel. Therefore, the water quality of the gazetted beaches along the Tsuen Wan coastal strip was "Poor" or "Very Poor" in 2001.
7. In order to permanently remove the potential pollution sources of the Tsuen Wan beaches, proper sewerage will be provided along Castle Peak Road from Ting Kau to Tsing Lung Tau. Sewage from village houses in the hinterland of the beaches will be collected and conveyed to a new sewage treatment plant to be built on reclaimed land in Sham Tseng. The construction of trunk sewerage has commenced in mid-1999, while the sewage treatment plant and submarine outfall will be built in 2002. The whole improvement works are scheduled for completion in 2005.
8. To alleviate the pollution problem of the Sham Tseng Nullah in the short to medium term before proper sewerage can be provided to the Sham Tseng area in 2005, two storage tanks had been built in 2000 to tanker away the wastewater from the refuse collection point, public toilet and temporary market for proper disposal. Furthermore, an additional interim secondary sewage treatment plant with disinfection facility has also been built and commissioned at the end of 2001 to improve the quality of effluent from the two communal septic tanks for the Sham Tseng Resite Village. Through these improvement measures, it is expected that the water quality of the Sham Tseng Nullah will improve, and beaches in the vicinity will be less affected by the discharges from the Nullah.
WEEKLY BEACH MONITORING
9. Starting from November 2001, lifeguard and other services are provided by the Leisure and Cultural Services Department at Deep Water Bay, Clear Water Bay Second and Golden Beach throughout the year. Hence, EPD has continued the weekly monitoring programme for these three beaches over winter months and has been issuing weekly press release on their beach grading throughout the year.
10. Updated information on beach grading for the three beaches is also available on the beach water quality webpage at EPD's homepage (http://www.info.gov.hk/epd) and at the beach water quality hotline at 2511 6666.
CONCLUSION
11. The improving water quality trend observed in the late 1990's had stalled in 2001 due to the abnormally high rainfall during the bathing season. The poor water quality of the Tsuen Wan beaches is expected to improve after the proposed sewerage works in the beach hinterland are completed within the next few years.
12. Starting from 2001, weekly monitoring and release of weekly beach grading have been continued during winter season for the three gazetted beaches which are opened all year round.
Environmental Protection Department
February 2002
