Concerns over the water quality of Dongjiang, a major source of fresh water for Hong Kong, are likely to evaporate now that a closed aqueduct has been built between the Dongjiang intake and the Shenzhen Reservoir.

The aqueduct goes into service today.

Quality assured: Assistant Director of Water Supplies Damien Ku says the construction of a closed aqueduct will help improve the quality of Dongjiang water supplied to Hong Kong; Bijiashan Tunnel for transporting Dongjiang water; Huizhou Meilake Water Purification Centre.

"In the early '90s, Dongjiang water quality started to deteriorate because of the industrial and population boom in Guangdong province," Mr Ku said.

"A lot of factories were established along the river conveying Dongjiang water to the Shenzhen Reservoir, causing a deterioration in the quality of raw water supplied to us."

Although the Guangdong authority built a number of sewage treatment works to deal with the issue, Dongjiang water's quality still remained a major concern for Hong Kong people.

"Although we can manage to deal with the water-quality problem and ensure that the water supplied to Hong Kong people meets the World Health Organisation's requirement, we still think we must to do something to solve the problem ultimately," Mr Ku said. 

After a series of discussions between the Government and the Guangdong authority, an agreement on enhancing the Dongshen water supply network was eventually reached in July, 1998.

The main focus of the project was to build a closed aqueduct to convey water from Dongjiang directly to the Shenzhen Reservoir, isolating the water to be supplied to Hong Kong from all possible pollution sources.

The project started in 2000 and was divided into four phases. It involved the construction of elevated water conduits, underground conduits, pumping stations and many related structures.

The Guangdong authority was responsible for all the design and construction work.

With a capacity for conveying 2.4 billion cubic metres of fresh water, the 59-km-long water-supply network runs from Taiyuan Pumping Station to Shenzhen Reservoir.

$2.3 billion interest-free loan provided to Guangdong 

The total cost of the project was about $5 billion and the Government provided an interest-free loan of around $2.3 billion to the Guangdong authority to fund the project.

"According to the agreement, the Guangdong authority will start repaying the loan later this year and the repayment will be spread over 20 years," Mr Ku said.

Apart from providing financial support to the project, Hong Kong officials also paid a number of visits to Guangdong to offer professional advice on the aqueduct design.

The construction had been carried out smoothly and the first stage of the construction was completed in January this year.

"Since the commissioning of the Part One aqueduct, we notice that there has been a marked improvement in water quality," Mr Ku said.

"With the completion of the whole project, we expect the quality of Dongjiang water supplied to Hong Kong will be further improved and the improvement will be sustained for years."

To solve the water-supply problem in Hong Kong, the Government decided to buy Dongjiang water from Guangdong in the '60s.

The Dongshen water supply network was eventually built in 1964 and started operating in 1965. Three expansion works have been carried out during the ensuing years to satisfy the increasing water demand from Hong Kong and other nearby Mainland cities.

Dongjiang supplies more than 80% of Hong Kong's annual fresh water consumption. This year, it will supply about 810 million cubic metres - about enough to fill High Island Reservoir three times over.