LCQ2: Replacement and rehabilitation of water mains

Following is a question by the Hon James Tien and a written reply by the Secretary for Development, Mrs Carrie Lam, in the Legislative Council today (April 23):

Question:

It has been reported that as the problem of aged underground water mains is becoming increasingly serious in Hong Kong, incidents of suspension of water supply have occurred from time to time in some districts.  The authorities have implemented the Replacement and Rehabilitation Programme of Water Mains ("the Programme") since 2000, but it is anticipated that all the works for replacing and rehabilitating water mains can only be completed by 2015.  On 30 March this year, the valve in an underground fresh water pipe (600 mm in diameter) beneath a section of Tai Po Road off Wo Che Estate broke down, resulting in suspension of fresh water supply in a number of housing estates and villages in Fo Tan area in Shatin.  In this connection, will the Government inform this Council:

(a)  apart from old water pipes, whether the Programme which is under implementation covers the replacement and rehabilitation of other components (such as valves) as well, and the latest progress of the Programme;

(b)  of the respective numbers of incidents of suspension of fresh water and salt water supplies in the past three years, which were caused by aged water mains or other aged components, broken down by district;

(c)  pending the replacement of water supply facilities which have been in use for a long time, whether the authorities will step up inspection of such facilities in various districts, so as to replace or rehabilitate them earlier once problems of ageing, rusting or cracking are detected; and

(d)  whether it will review afresh whether the above Programme can be expedited for earlier completion; if the outcome of the review indicates that the Programme can be expedited for earlier completion, of the details; if not, the reasons for that?

Reply:

Madam President,

Hong Kong has an extensive water supply system of about 7,700 km of water mains.  To enhance the quality of water supply service, reduce the wastage of water resources, and mitigate the nuisances and economic losses due to pipe bursts, the Government has since 2000 been implementing the Replacement and Rehabilitation Programme of Water Mains (the Programme). The aim is to replace and rehabilitate about 3,000 km of aged water mains throughout the territory.  Given the enormous scale of the Programme, it is to be implemented in four stages, with the final stage scheduled for completion in 2015.  With respect to the four parts of the question, I wish to tender a reply as follows:-

(a)  In addition to aged water pipes, the Programme also covers the replacement and rehabilitation of other components such as valves.  Works for the first two stages of the Programme have commenced, and the remaining two stages will start in this autumn and 2011 respectively.  As regards the overall progress of the Programme, works have already been completed on about 460 km of water mains and in progress on about 890 km of them.  The lengths of water mains under detailed design and planning are about 800 km and 850 km respectively.  It is estimated that all the works will be completed by 2015.

(b)  The breakdown by district of the number of incidents of suspension of fresh and salt water supplies caused by aging of water mains or other components over the past three years is as follows:

(c)  Pending replacement of aged water supply facilities, the Water Supplies Department (WSD) has drawn up guidelines requiring that every incident of water supply suspension or serious traffic disruption as a result of pipe burst or component failure should be examined in detail.  The aim is to establish the cause of the incident and to step up necessary checking on the associated water mains networks, for early identification of pipes with latent problems for maintenance or replacement as appropriate.

(d)  In most cases, replacement and rehabilitation of water mains requires road excavation.  It will, therefore, seriously disrupt road traffic and cause inconvenience to the public if the works programme is to be conducted within a very short time.  With this in mind, we have decided, after detailed planning, to implement this enormous programme in four stages so as to minimise traffic disruption and inconvenience to the public.  WSD will continually review the construction processes and schedules and actively explore ways to speed up the works and strive for completing most of the works before 2015 so far as it would not cause undue impact on both the traffic and the public.

Ends/Wednesday, April 23, 2008
Issued at HKT 14:54

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