Waterworks Infrastructure

Water Intelligent Network (WIN)

The Department plans to progressively implement the Water Intelligent Network (WIN) by installing sensors for the establishment of District Metering Areas (DMAs) and associated Pressure Management Areas (PMAs) in the water supply network. There will be about 2,000 DMAs throughout the entire territory under WIN. A computer system will be put in place to enable intelligent (and where necessary real-time) network performance analysis of the data collected from the sensors for monitoring the conditions of the water supply networks.

The Department has continued to install flow meters and pressure management equipment as well as instrumentation within the distribution systems in twelve of the seventeen major supply zones. For the remaining major supply zones, the investigation studies have been completed and we plan to go forward and begin the detailed design stage. As of March 2015, we have successfully installed some 700 District Metering Areas (DMA) with 165 of them serving as Pressure Management Areas (PMA). Ultimately, we plan to establish about 2,000 DMA/PMAs in Hong Kong. With more of these DMA/ PMAs commissioned, we will be able to continuously monitor the daily flow, pressure and minimum night flow. This will obviate the need to carry out separate minimum night flow testing on site.

Expanding Water Supply Capacity

As a major infrastructural cornerstone, water supply is critical to support Hong Kong’s future development. For this reason, new service reservoirs in Tung Chung are now being planned to cope with the increase in water demand resulting from upcoming major developments in North Lantau, including the proposed remaining development projects in Tung Chung and the future third airport runway project.

To deal with expanding housing developments in Sheung Shui, Fanling and Tai Po in the New Territories, new service reservoirs with associated trunk and distribution systems will be constructed to meet the increasing water demands there. Part of the proposed works in the Sheung Shui and Fanling areas will be specially designed so that they can be easily converted to form part of the future reclaimed water supply system for flushing.

Upgrading Water Treatment Facilities

The Sha Tin and Tai Po Water Treatment Works are currently in the detailed design and construction stages respectively to allow major capacity increases. These two facilities are important centres for the treatment of raw water prior to its distribution across Hong Kong. Re-provisioning work will be carried out at the Sha Tin plant while Tai Po will undergo a major expansion of its capacity and operations. Both projects will help ensure adequate capacity to produce the highest levels of potable water for the public. These projects are being delivered in phases to match closely with the greater demand for water throughout the Territory.

Once the two-phase, about HK$6 billion facilities upgrade is completed at the Tai Po Water Treatment Works, its overall capacity will increase from 250,000 to 800,000 cubic metres per day. Phase one has been completed and is now processing 400,000 cubic metres of water per day. Phase two begun in 2013 will see an eventual capacity increase to 800,000 cubic metres per day by its commissioning date in 2017. The on-site reprovisioning of the Sha Tin facility is scheduled for commencement in late 2015 and will be commissioned sometime by the year 2023.

Clarifier at Sha Tin Water Treatment Works Photo

Replacement and Rehabilitation Works

To reduce leakage, the Department is implementing a territory-wide Replacement and Rehabilitation (R&R) programme to replace and rehabilitate about 3,000km of aged water mains out of Hong Kong’s 8,400km of water mains. The work is expected to be largely complete by the end of 2015.

Improving Waterworks Operational Efficiencies

We have completed a review focusing on the enhancement of the monitoring and control facilities of our major treatment works in which the existing manual control equipment will be mechanised with remote control facilities in order to enhance overall operational efficiency.

We have continued our work to upgrade the four regional SCADA systems that are used to monitor and control water supply facilities including pumping stations and service reservoirs. In each region, the centralised control centre will be backed up with an alternative control centre to improve the operational reliability of the water supply network. The upgrading of the SCADA systems for the New Territories West Region and the Hong Kong & Island Region and the SCADA Information System are now completed. The remaining SCADA systems for the Kowloon Region and the New Territories East Region are scheduled for completion by the end of 2015 and 2016, respectively.

Chlorine scrubbers, which prevent chlorine gas from leaking into the atmosphere in the unlikely event of a system failure, are protective devices to keep water treatment works operating safely at all times. Following the completion of the modernisation and replacement of the chlorine scrubber system at the Silver Mine Bay Water Treatment Works, upgrading at the Yau Kom Tau Water Treatment Works got underway as well in 2014/15. Similar upgrading projects will be initiated at the Pak Kong Water Treatment Works and other key water treatment facilities to ensure reliable and safe operations.

Optimising Waterworks Assets

At the WSD, one of our primary goals is to manage the life cycles of all water services infrastructure in order to achieve the optimal level of service in the most cost-effective manner within an acceptable risk framework.

With the rapid advancement of Building Information Modelling (BIM) technology in recent years and its success in bringing about the cost-effective delivery of construction projects, the WSD has taken the initiative through a pilot study to explore the potential benefits of BIM applications in the asset management. Under this study, the Tai Po Salt Water Pumping Station and Telegraph Bay Salt Water Pumping Station were selected for the pilot study on trial use of BIM for asset management. The pilot study began in mid 2014 and is set for completion in mid-2015.

During the past year we completed four surface asset management plans, one for each of the four Regions, which identify the performance and physical condition of nearly 900 waterworks installations. Once an area of improvement has been identified, we prioritise this for implementation during the ensuring years. Our staff routinely inspects 6,500 slopes that fall under our maintenance responsibility. Last year we carried out subsequent preventive maintenance and upgrading work for nearly 80 slope features mainly near important installations of WSD. This work included soil-nailing, slope surface stabilisation, construction of toe planter walls, improvements to drainage systems, providing safe access corridors, planting and other measures. The result of all these efforts has been a dramatic decrease in the risk of landslides as well as the danger they pose to life and property.

We also regularly conduct inspections to review the safety and stability of service reservoirs and impounding reservoirs, making recommendations for maintenance work to ensure each reservoir’s integrity. During the past year, we completed 103 detailed inspection reports as well as 33 independent inspection reports by our internal staff and external advisors, respectively.

The project for implementing Reliability Centred Maintenance for two key pumping stations as well as a water treatment works installation has been completed. In order to develop more comprehensive templates of maintenance strategies for various kinds of waterworks installations, additional projects for two more pumping stations will be conducted in the coming year.

To formulate a comprehensive replacement programme for aged plant equipment, condition assessments for 12 pumping stations have been completed with assessments for another 16 installations to be carried out in the coming year.

An optical Fibre Bragg Grating (FBG) sensory system has been implemented for on-site trial monitoring of the structural integrity of a 200-metre long underground Dongjiang water pipe section. A computational system has also been established for tracking raw data collected from the on-site trial monitoring (i.e. physical parameters, including pipe strains, temperature and water pressure). Having analysed the monitoring data collected over the past two years, threshold values of pipe strain were determined and a two-level triggering mechanism was designed for on-going monitoring with the aim of preventing bursts and leaks.