To maintain the healthiness of the water distribution network and manage water loss effectively, the Water Supplies Department (WSD) has applied various technologies to handle water main leaks. In particular, the Water Intelligent Network (WIN), which is being established progressively, continuously monitors the operation of the network by utilising advanced technologies for early identification of water leaks and timely follow-ups and repairs. This time, I have invited colleagues from the WSD to talk about the progress, effectiveness and way forward of the WIN project. Meanwhile, the property management industry also shares details on how the WSD assists property owners and building management agents to carry out leak detection and repair works for their private communal water mains.

Managing water supply network is challenging

The water supply network of Hong Kong comprises water mains of total length of more than 8 000 kilometres, most of which are laid underground. The network is massive and complex. Furthermore, the hilly terrain of Hong Kong makes the water supply pressure generally higher than that of other cities. On top of that, busy traffic and frequent roadworks cause disturbance to underground water mains. All these factors contribute to an increasing risk of water mains bursts or leaks, making it a great challenge to the WSD to manage the water supply network.

Continuous monitoring of the network condition

The WSD has been taking a multi-pronged approach to tackle the problem. Apart from replacing and rehabilitating aged water mains, the department has also launched the WIN project. Senior Engineer (Water Loss Management) of the WSD, Mr CHEUNG Kwan-shek, says the WIN divides the fresh water distribution network into many discrete District Metering Areas (DMAs) with advanced monitoring and sensing equipment installed to collect water flow and pressure data as well as other data. The data collected will then be analysed by a computer system for continuous monitoring of leakage of the water distribution network. Under the project, the fresh water distribution network in Hong Kong will be divided into about 2 400 DMAs. So far more than 1 300 DMAs have been set up and the remaining ones are expected to be established by 2024.

About 400 leaks in fresh water mains detected last year

Regarding effectiveness, the WSD detected about 400 leaks in fresh water mains last year through WIN, including some in individual large-scale concealed water mains leaks. Upon follow-ups and completion of repair works, water loss has been effectively reduced. Mr CHEUNG Kwan-shek tells us that, in line with the future development of WIN, the WSD will introduce more advanced water mains leakage detection technologies, such as a spherical floating equipment with a built-in leakage detection device which is able to locate leaks inside water mains while floating in the direction of water flow. With the new technologies, which are more accurate and more sensitive than traditional methods, working in conjunction with the WIN’s monitoring equipment, leakage in the water distribution network can be further reduced.

Formulation of effective network management measures

According to Engineer (Water Loss Management) of the WSD, Mr LIU Kai-chun, the implementation of WIN can help the WSD to prioritise District Metering Areas (DMAs) for follow-up actions according to the degree of water loss, and enable the department to formulate effective network management measures to maintain the healthiness of the water distribution network.

The related measures include (i) active leakage detection and control by collecting data from WIN to identify DMAs with obvious water loss for repair through on-site step tests, detection and location of water mains leaks by leak detection team ; (ii) dividing supply zones with higher water pressure into discrete Pressure Management Areas (PMAs) and reducing their excessive pressure to a suitable level through the installation of pressure reducing devices so as to minimise water mains leakage and extend the service life of water mains; (iii) conducting quality and speedy repair to water mains leaks and bursts; and (iv) replacement or rehabilitation of water mains which are beyond economic repair.

Helping with early detection of water mains leakage in private housing estates

Due to aging of the water pipes, there may be leakage in the underground communal pipes of some housing estates. Former chairman of the Hong Kong Association of Property Management Companies Limited, Mr TAM Kwok-wing, says that WIN and a series of measures taken by the WSD have successfully helped property owners with early awareness of leakage problems. The WSD has also offered necessary technical support to help property management companies to follow up on these cases. Moreover, by holding briefings and publishing a Guideline on Leak Detection on Underground Communal Service of Housing Estates, the department seeks to raise the awareness and understanding of property owners and property management companies on detecting leakage and repairing water mains proactively. The department also provides a reference list of local service providers of leakage detection on its website to help property owners and property management companies in hiring contractors.

Water is a precious natural resource that we should cherish. I am pleased to see that the WSD’s WIN project has been effective in reducing water loss. Meanwhile, I encourage the department to continue to explore the use of advanced technologies to enhance the management of the water supply network, so that water mains leakage can be detected early to minimise the inconvenience and property damage caused to the public.