Water Supply Management

In Hong Kong we rely primarily on two main sources of fresh water, namely imported water from Dongjiang in Guangdong, and rainwater from catchment facilities located throughout the territory. 2013 saw about 66% of our water source flow through a dedicated aqueduct from Guangdong, a reduction of 10% from the previous year due to higher rainfall. The remaining 34% of our water sources comes from local yield. During the maintenance periods of the aqueduct when the flow of water from Guangdong must be closed, we use the water stored in the Plover Cove or High Island impounding reservoir to meet our daily needs.

In addition to potable water sources, we also place great importance on the application of sea water for toilet flushing. This is supplied through seafront salt water pumping stations that cover about 80% of Hong Kong’s population. In 2013, the construction of a new salt water supply system was substantially completed, ready to provide seawater for flushing in the Pok Fu Lam area. Taking careful consideration of these current water sources, the Department continues to seek new local alternatives for both potable and non-potable water to maintain acceptable levels of reliance on Dongjiang’s water supply.

Local Yield

All across Hong Kong, covering nearly 30% of the territory, are rainfall catchment areas the contents of which are stored in 17 impounding reservoirs. In general, rainwater is largely uncontaminated. However, as additional measures for safety, the Department makes regular inspections, checks water quality, carries out necessary maintenance and removes of all debris in the water. Local yield generally accounts for about 20–30% of our total fresh water consumption.

Fresh Water from Dongjiang

Water imported from Dongjiang, Guangdong generally accounts for 70-80% of our total fresh water consumption. Our current contractual agreement for the supply of water from Dongjiang takes into account the daily needs of Hong Kong as well as the existing water supply situation in Guangdong. The current agreement has adopted an annual supply ceiling of 820 million cubic metres which will satisfy all of Hong Kong’s domestic and non-domestic needs with 99% water supply reliability, i.e. water supply is maintained around the clock even under extreme drought conditions with a return period of once in 100 years. We balance the monthly amount of water we draw in from Guangdong against local seasonal rainfall amounts to optimise local resources as much as possible. The current 3-year agreement for the cost of water from Guangdong breaks down to: HK$3,539 million, HK$3,743 million and HK$3,959 million for the years 2012, 2013 and 2014, respectively. Talks are now underway with Guangdong authorities over price, water quality and other matters for the years after 2014. Final agreement is expected to be reached by the end of 2014.

We benefit greatly from the strong and amicable partnership nurtured between Hong Kong and Guangdong water officials. Moreover, each year members of the Hong Kong Advisory Committee on Water Resources and Quality of Water Supplies (ACRQWS) visit Guangdong to discuss various water issues. In November 2013, Committee members were briefed on the latest measures being taken in Dongjiang to assure water quality coming into Hong Kong. Our efforts at closely controlling water storage levels at local impounding reservoirs as well helps us minimise water waste and optimise pumping expenses. The Department closely monitors water transfer operations to ensure that there is a high degree of transparency in terms of water quality and security.

Fresh Water Alternatives

Moving Forward with Desalination

The Department is always concerned with issues surrounding water supply management and we actively explore all viable options for obtaining new water resources that will better withstand the unknown consequences of climate change. With this in mind, in 2012, an investigative study was undertaken for the construction of a reverse osmosis desalination plant to start operations in Tseung Kwan O by 2020. This plant is expected to achieve an initial output capacity of 135 MLD per day, which would supply about 5% (later expandable to about 270 MLD or 10%) of the total fresh water needs in Hong Kong. Preliminary investigation studies are still on-going and are expected to be completed by 2015.

Use of Reclaimed Water

We have also begun planning the supply of reclaimed water being converted from tertiary treated sewage effluent from the Shek Wu Hui Sewage Treatment Works to Sheung Shui, Fanling and North East New Territories New Development Areas for non-potable applications. The supply of reclaimed water will tentatively be commissioned in phases in 2022 and will ultimately help save Hong Kong about 21 million cubic metres of fresh water each year.

Grey Water Re-Use and Rainwater Harvesting

Grey water is the general term that refers to the water collected from baths, showers and wash basins, etc. These sources of water are normally less contaminated, and as such can be more readily be treated and re-used for non-potable applications like toilet flushing and irrigation. By the same token, rainwater can also be collected and used for these purposes. The government is taking the lead in implementing grey water re-use and rainwater harvesting measures but the Department is also encouraging private real estate developers to include re-use technologies into their developments.