Guangdong's provincial water resources department will make the Pearl River Delta project the top priority in the coming two years in order to secure the water supply of Hong Kong, a senior official said on Tuesday.

The department has submitted the Pearl River Delta Water Resources Allocation Project to the Ministry of Water Resources for approval. The project is designed to pump water from the Xijiang River valley to the Dongjiang River valley, which is the main fresh water supply for Hong Kong. It will also serve as a supplemental water supply for Shenzhen, Dongguan and Guangzhou.

Zhou Dejiao, the top manager of Guangdong's water supply projects, pointed to the increasing disparity in recent years between supply and demand for Dongjiang River water.

"The Dongjiang River is the main water source for Hong Kong, eastern Guangzhou, Shenzhen, Dongguan, Heyuan and Huizhou. It also serves many other functions such as flood control, power generation and shipping," Zhou said.

"As consumption in the basin grows with the development of these cities, the use of Dongjiang River water has reached its limit."

Designed to pump 1.78 billion cubic meters of water annually from the Xijiang River to the Dongjiang River, the Pearl River project will ease the problem, Zhou said.

"After the project's completion, we will pump the water through a delivery network within Shenzhen into the Shenzhen Reservoir in emergencies, such as severe droughts, to guarantee the water supply for Hong Kong."

Hong Kong, a seaport with few natural lakes or rivers, has relied on mountain streams and rain as its main sources of fresh water. It suffered a long drought from May 1963 to June 1964, when residents were supplied with fresh water only once every four days.