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Following is a question by the Hon Lau Kong-wah and a written reply by the Secretary for the Environment, Transport and Works, Dr Sarah Liao, at the Legislative Council meeting today (November 30) :
Question:
It is learnt that as a result of heavy rainfall in Summer this year, a number of reservoirs are overflowing, necessitating the discharge of water into the sea. In this connection, will the Government inform this Council of:
(a) the monthly quantities of water discharged into the sea since May this year, the value of such water as calculated by the current unit price of water supplied to Hong Kong, and how these figures compare to those of the past two years; and
(b) the progress of its negotiations with the Guangdong provincial authorities on the new water supply agreement, and whether the negotiations cover the issue of flexibility in the supply of water?
Reply:
Madam President,
Owing to topographical and capacity constraints, the reservoirs in Hong Kong may overflow during the rainy seasons. The accumulated rainfall in Hong Kong from January to October this year amounts to 3,203 mm, which is over 49% above the average of 2,152 mm for the same period and nearly 45% above the annual average of 2,214 mm. The month of August this year was also the second rainiest August since records were kept in 1884. The amount of rainfall recorded in that month was 971 mm, about 148% more than the average of 391 mm for August. Moreover, the accumulated rainfall recorded on 19 and 20 August was 546 mm, breaking the record of accumulated rainfall of two consecutive days in August. The local reservoirs have started to overflow since May.
(a) The amount of overflow from reservoirs in 2003, 2004 and 2005 (January to November) is tabulated below:
Amount of Overflow
Year/month (million cubic metres)
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2003 (whole year) 14.4
2004 (whole year) 6.5
2005 (January to November) 109.4
2005 (May) 0.3
2005 (June) 16.9
2005 (July) 6.8
2005 (August) 79.4
2005 (September) 5.0
2005 (October) 1.0
2005 (November) 0.0
Annual rainfall in Hong Kong varies considerably. Since records were kept by the Hong Kong Observatory in 1884, the highest annual rainfall was 3,343 mm in 1997, while the lowest annual rainfall was 901mm in 1963. The rainfall recorded in 2003 and 2004 was 1,942 mm and 1,739 mm respectively, which were lower than the average. Hence, the amount of overflow from reservoirs in these two years was relatively small. Owing to heavy rainfall this year, the amount of overflow from reservoirs has reached 109.4 million cubic metres up to November. To reduce overflow from reservoirs, the Water Supplies Department (WSD) has taken measures in the rainy season by drawing water to water treatment works from those reservoirs which are nearing capacity, so that the chance of allowing overflows into the sea can be reduced.
As all the water overflowing from reservoirs is natural rainwater instead of Dongjiang water supplied to Hong Kong, it is neither reasonable nor appropriate to base the calculation of its value on the price of Dongjiang water. The WSD has conducted a feasibility study on various subjects, including the feasibility of increasing the storage capacity of reservoirs to reduce the amount of overflow. The study concludes that it is not cost-effective to increase the current storage capacity of reservoirs as it will incur substantial project and operation costs, which are higher than those of increasing water supply through other means such as the purchase of Dongjiang water or desalination. Moreover, it will have impacts of various degrees on the countryside and the ecological environment.
(b) According to our existing agreements* with the Guangdong provincial authority, long-term supply of Dongjiang water has been guaranteed. Guangdong and Hong Kong are maintaining liaison and contacts over the negotiations on the arrangements for supply of Dongjiang water to Hong Kong. Several rounds of negotiations have already been held. We hope that a new water supply agreement with Guangdong will be concluded shortly and we will report on the outcome in due course.
In discussing the new water supply agreement, consideration is given to a flexible supply arrangement, whilst taking into account the overall interest of Hong Kong.
* Existing agreements include the 1989 Water supply Agreement and the 1998 Loan Agreement
Ends/Wednesday, November 30, 2005
Issued at HKT 14:46
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