Reducing water pipes leakage requires departmental collaboration

November 29, 2023 09:17
A water pipe burst, flooding part of a road and causing a sinkhole. Photo: RTHK

Water leakage in the public water networks is a perennial problem.

Mainland media reported in 2021 that the leakage rate of water pipes in some cities and towns reached 30%, and the public water supply network in cities and counties across the country leaked nearly 10 billion tons of water in 2019, equivalent to the water storage capacity of 700 West Lakes in Hangzhou (or about 2.8 million Olympic swimming pools).

The situation in Europe is not much better either. The European Federation of National Associations of Water Services (EurEau) estimates that 25% of Europe's water is lost due to leakage every year, equivalent to millions of Olympic swimming pools. For example, in Italy, with a population of nearly 60 million, more than 40% of water pipes leak, losing 1.72 million swimming pools of water a year. Only a few countries, such as Germany, the Netherlands and Denmark have leakage of less than 10%.

Advanced technology is used everywhere to address the problems. In Europe, for example, the vast network of water pipes stretches 4.3 million kilometers (about 11 times the distance between the Earth and the Moon), and it can be difficult at times to find the source of the leak, especially in the rural areas. Some companies use acoustic systems and smart sensors to detect fluctuation in water flow and pressure in real time to identify problems, while thermal cameras mounted on drones detect leakage underground.

At the same time, China has set hard targets for water leakage control. In March this year, the central government selected 50 cities as pilots to carry out leakage control in public water supply networks for three years. If the pilot water pipe leakage rate is above 12% in 2020, it must be improved to no more than 8% by 2025. In addition, by then, the leakage rate of the national urban public water supply pipe network should strive to be within 9%. The goal is very ambitious.

Hong Kong is also plagued by leaking water pipes. Since 2000, the Water Supplies Department has launched a comprehensive water network management programme to replace and rehabilitate 3,000 km of water pipes in phases over 15 years, and the number of burst water pipes has dropped significantly from 2,500 in 2000 to 40 cases last year. During the same period, the leakage rate of fresh water pipes also decreased from 25% to 14.4%, and it has set a target to control the leakage rate at below 10% by 2030.

How to achieve it?

The Hong Kong-wide fresh water distribution network has been divided into roughly 2,400 monitoring areas with monitoring and sensing equipment being installed in each area to record data such as water flow and water pressure changes. Through the Digital Mapping System with geographic information system (GIS) as the core, it can acquire, store, integrate and maintain digitised geospatial data across the water supply network.

Digitisation of information facilitates internal communication to monitor the latest progress of water pipe replacement and restoration works. When working with other departments and utilities undertakers, information flow is also more uniform and convenient.

In addition to the high water supply pressure due to the hilly topography, congested urban setting has posed huge challenges in maintaining a highly sustainable water supply network. Some industry insiders pointed out that even if you know the location of leaking, digging up the roads during day time will cause traffic congestion, and noise at night operations. As a result, it is difficult to obtain approval for maintenance works. Some people joked that the authorities had to wait until the water pipes burst. By then, all authorities have to approve the work to proceed although greater disturbance to the public has to be endured.

It seems that in addition to using advanced technology to manage water resources, the authorities need to further strengthen collaboration with different departments, which would be a big step toward reducing leakage from water pipes.

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Adjunct Professor, Department of Computer Science, Faculty of Engineering; Department of Geography, Faculty of Social Sciences; and Faculty of Architecture, The University of Hong Kong

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