LCQ20: Incidents of fresh water main bursts
Following is a question by the Hon Kwok Wai-keung and a written reply by the Secretary for Development, Mr Paul Chan, in the Legislative Council today (February 12):
It was reported that last month, fresh water supply in the Western District was suspended for five hours due to the burst of an underground fresh water main, and it was estimated that at least 40 000 residents and a large number of eateries were affected. Regarding the prevention of water mains from bursting and handling of such incidents, will the Government inform this Council:
(1) whether it has received complaints about the aforesaid incident; if it has, of the number of such complaints and their main contents; how the authorities followed up such complaints;
(2) of the channels through which the authorities disseminate information on suspension of fresh water supply to the residents and eateries in the affected areas in general;
(3) of the details of each incident of fresh water main bursting since January 2013, broken down by District Council (DC) district, including (i) the location of the burst water main, (ii) the duration of the resultant fresh water supply suspension, and (iii) the number of years for which the water main concerned had been used; among such incidents, the number of those involving water mains which had been used for less than 30 years; and
(4) given that the Water Supplies Department commenced the Water Mains Replacement and Rehabilitation (R&R) Programme in 2000 to replace and rehabilitate aged water mains in phases, of the respective total length of water mains for which works have yet to start in various DC districts at present, and the relevant works schedules; whether the authorities will, upon completion of the R&R Programme in 2015, gradually replace and rehabilitate water mains with relatively shorter years of service (e.g. less than 30 years); whether the authorities at present carry out repairs and maintenance of such water mains on a regular basis; if they do, of the manpower and expenditure involved; if not, the reasons for that?
On receipt of the report of a burst involving an 18 inch diameter cast iron fresh water main at Pokfulam Road near Haking Wong Building of the University of Hong Kong in the evening of December 31, 2013, the Water Supplies Department (WSD) immediately dispatched staff to the scene to shut down the burst main and carry out emergency repair work. The fresh water supply at High Street as well as the area from First Street to Third Street was affected. After the burst section of the water main was completely isolated, the WSD noticed at noon on January 1, 2014 that fresh water was still gushing from inside of the water main because two valves in the upstream could not be closed completely due to ageing. Therefore, the WSD had to turn off the main valve at the Western Fresh Water Service Reservoir before they could lay the new water main and complete the repair work. As a result, the fresh water supply to other buildings in the Western District was also affected at 5pm on January 1, 2014. At about 9pm that day, the WSD finished the repair work and resumed water supply.
The water main concerned has been in use for over 30 years and the burst incident was due to ageing. That section of water main was included in Stage 4 of the R & R Programme and the concerned works contract commenced in May 2011. To tie in with the programme of the West Island Line project of the MTR Corporation Limited (MTRCL), the replacement works for the water main section concerned were originally scheduled to commence after the completion of the West Island Line in 2014, so as not to hinder the progress of the West Island Line project by the temporary traffic arrangement for the water main replacement works. In the light of the incident, the WSD is now negotiating with the MTRCL to explore the feasibility of bringing forward the replacement works for the section of water main to an earlier date.
The WSD has been taking a multi-pronged approach in tackling the problem of ageing water mains. In addition to the R & R Programme, it has strived to reduce the risk of water main burst by way of leakage detection and water pressure management. These efforts have reaped positive results, with the number of water main burst incidents dropping from a peak of about 2 500 in 2000 to about 260 in 2013.
My reply to the four parts of the question is as follows:
(1) During the incident, the WSD immediately deployed water wagons, water tanks and temporary standpipes to provide fresh water for the affected residents and shops. The WSD received over 700 telephone enquiries about the incident, including the reasons for water supply suspension, the time when water supply would be resumed, the number and locations of water wagons, water tanks and temporary standpipes provided, etc. The WSD also received the concerns of the Central and Western District councillors on January 2 and 6, 2014 as relayed to them by the District Council. In this connection, the WSD reported on details of the incident, the way they handled it and the progress of replacement for the section of the water main concerned at the meeting of the Food, Environment, Hygiene & Works Committee of the Central and Western District Council on January 16, 2014. The WSD has no record of receiving any further enquiry or complaint about the incident.
(2) Generally, the WSD would announce emergency suspension of fresh water supply on its website. In cases where the affected area is extensive, the WSD would issue a press release and inform the public of the emergency suspension through the media, such as the radio.
(3) There were 138 fresh water main burst incidents between January 2013 and January 2014. 19 of them involved water mains that have been laid for less than 30 years. Details of these incidents, including the District Council districts in which they occurred, are shown in Annex 1.
(4) The WSD has launched the R & R Programme to replace and rehabilitate 3 000 kilometres (km) of aged water mains in stages since 2000. As at January 2014, works have been completed for 2 336 km of water mains (accounting for 78 per cent of the total length under the programme). The respective lengths of water mains for which works have yet to be carried out in each District Council district under the R & R Programme are shown in Annex 2. Contracts for the replacement and rehabilitation of these water mains have already commenced and are expected to be completed in stages by the end of 2015.
The current R & R Programme will be completed in 2015. The WSD is reviewing its effectiveness and examining ways to integrate it more closely with other related measures, including leakage detection and water pressure management, in order to determine the scale and pace of the next stage of the R & R Programme for more effective improvements to the conditions of the water main networks.
Under the current establishment of the WSD, about 500 staff members are engaged in the operation, repairs and maintenance of water mains. They are responsible for the daily monitoring and operation of the water main networks; regular inspection, repairs and maintenance of associated facilities; and emergency repair works. In 2013-2014, the expenditure of maintenance and repair works for water mains (as at January 2014) amounted to about $180 million. The above figures cover the manpower and expenditure for maintaining the entire water main network under the WSD, including the water mains that have been laid for less than 30 years.
Ends/Wednesday, February 12, 2014
Issued at HKT 14:52