LCQ8: Management of water resources

Following is a question by the Hon Claudia Mo and a written reply by the Secretary for Development, Mr Eric Ma, in the Legislative Council today (June 7):


The fresh water of Hong Kong mainly comes from Dongjiang water and rainfall from local catchments, which respectively account for 70 per cent to 80 per cent and 20 per cent to 30 per cent of Hong Kong's fresh water supply. Regarding the management of water resources, will the Government inform this Council:

(1) of the cost per cubic metre for processing Dongjiang water in each of the past five years;

(2) given that in February this year, the Government commenced the negotiation with the Guangdong authorities in respect of the agreement on the supply of Dongjiang water to Hong Kong in the coming three years, of the procedure and latest progress of the negotiation;

(3) of the number of reservoirs which overflowed in the past five years, and the overall quantity of overflow from reservoirs last year;

(4) of the causes for the incidents of pipe leakage, and the percentage of the quantity of fresh water so leaked in the annual total water consumption, in each of the past three years;

(5) given that the Water Supplies Department (WSD) and the Drainage Services Department have, since 2004, made plans to implement the Inter-reservoirs Transfer Scheme to channel the overflow from the Kowloon Group of Reservoirs to Lower Shing Mun Reservoir and to convert such overflow into potable water resources, but the Government reportedly deferred the implementation of the Scheme due to the implementation of a number of infrastructure projects in the past, whether the Government will accord priority to the implementation of the Scheme; if so, of the details; if not, the reasons for that;

(6) as the WSD plans to progressively establish a "Water Intelligent Network" to enable continuous monitoring of the conditions of the water supply networks in the territory, of the latest progress, work schedule and completion date of the project; and

(7) as the WSD is developing a smartphone application named Smart Metering System, of the relevant details and progress?



Hong Kong's fresh water resources mainly come from rainfall. Nevetheless, the rainfall is unstable and the yield collected from local catchments is inadequate to meet our needs. Therefore, Hong Kong needs to import Dongjiang water to fill the gap arising from inadequate local yield.

However, there is competing demand for Dongjiang water from cities in the Guangdong Province. As a good partner city in the Pearl River Delta Region, we need to manage our water resources properly to ensure its sustainable use.

My reply to the seven parts of the Hon Claudia Mo's question is as follows:

(1) To enhance operation efficiency and assure a reliable and stable water supply, in general, Dongjiang water is transported to water treatment works, either directly or by way of impounding reservoirs, and pooled with the rain water collected locally for treatment. As such, the Water Supplies Department (WSD) does not have a separate breakdown of the expenditures for processing Dongjiang water. The table below sets out the unit treatment cost (note) for potable water (including Dongjiang water and rain water collected locally) in Hong Kong for the past five years:

Note: The unit treatment cost excludes the costs for transport, distribution and customer services, etc.

(2) With the current agreement for the supply of Dongjiang water due to expire at the end of this year, we have commenced negotiation with the Guangdong authorities for a new agreement since February 2017. To date, we have conducted four rounds of negotiations and covered the main issues of the new agreement, including the water quality, supply quantities, charging model and water prices, etc. We have also proposed to the Guangdong side to explore the feasibility of adopting the "payment on actual supply quantity" model as proposed by some Legislative Council members.

(3) Since the adoption of the "package deal lump sum" and flexible supply arrangement in the Dongjiang water supply agreements in 2006, we have been able to effectively control the overflow from impounding reservoirs. Indeed, overflow from local impounding reservoirs has been drastically reduced by about 71 per cent, from an annual average of around 94 million cubic metres between 1996 and 2005 to around 27 million cubic metres in recent years (from 2006 to 2016). At present, overflow mainly occurs in small to medium impounding reservoirs, which were built between the end of the 19th century and the middle of the 20th century. As these reservoirs were designed to meet the water needs then, they featured relatively small storage capacities and are prone to overflow in times of persistently heavy rainstorms in the rainy season.

Impounding reservoirs/reservoir groups which have overflown over the past five years include the Tai Tam Group of Reservoirs, Kowloon Reservoir Group, Aberdeen Group of Reservoirs, Shek Pik Reservoir and Tai Lam Chung Reservoir. The volume of reservoir overflow is largely dependent on the weather and rainfall of the year concerned. For instance, the volume of reservoir overflow reached 28.5 million cubic metres in 2016 while that in 2015 was 3.3 million cubic metres only.

(4) Given the hilly terrain of Hong Kong, service reservoirs need to be built at high altitude in order to facilitate water supply to premises at different levels. Hence, water mains at lower altitudes operate under relatively high water pressure most of the time. The ageing of some water mains and disturbances arising from such factors as frequent roadworks, ground settlement, external loading and vibration further exacerbate the problem and make the water distribution networks prone to leakage.

With the Replacement and Rehabilitation Programme of Water Mains substantially completed, the condition of the water distribution networks has improved greatly. The number of main bursts and leakage rate in water mains have reduced significantly. The water mains leakage rate has dropped from about 25 per cent in 2000 to 16 per cent in 2014 and about 15 per cent in 2015 and 2016.

(5) We took the opportunity during the formulation of the Lai Chi Kok Transfer Scheme for reducing the flood risks in the West Kowloon region to take forward the Inter-Reservoirs Transfer Scheme (IRTS) concurrently. Under the IRTS, a tunnel connecting the Kowloon Byewash Reservoir and the Lower Shing Mun Reservoir will be built to transfer the overflow from Kowloon Reservoir Group to the Lower Shing Mun Reservoir to achieve the dual objectives of reducing the run-off flowing into the Lai Chi Kok drainage system and converting the overflow into potable water resources. Currently, the Drainage Services Department is reviewing the detailed design, method statements and related environmental impact assessments of the IRTS in order to enhance its cost-effectiveness and prepare the implementation schedule to proactively take forward this project.

(6) Under the Water Intelligent Network (WIN) project, the water distribution networks of Hong Kong will be divided into some 2 000 discrete District Metering Areas (DMAs) of manageable size, with monitoring and sensing equipment installed in the distribution network of each DMA. The WSD is also working to provide an intelligent network management computer system to analyse the tremendous amount of data collected from the DMAs to formulate the most effective network management measures and their respective priorities for individual DMAs. As at March 2017, around 1 000 DMAs have been set up. We expect that the whole WIN will be put in place in five years' time.

(7) The WSD has developed an Automatic Meter Reading application for smartphones which provides the latest records on domestic water consumption to help the public conserve domestic water consumption and monitor water loss from inside services. The WSD is testing the application at the public housing estates and government quarters that have been previously installed with smart water meters.

Ends/Wednesday, June 7, 2017
Issued at HKT 12:40