The Three Gorges reservoir officially began to store water as the sluice gate started to close at 00:00 Sunday.
The water level will rise by four to five meters daily and is expected to reach an altitude of 135 meters by June 15. Navigationon the Yangtze River is planned to resume on June 16 after having been suspended for 67 days.
By then, a huge reservoir will gradually emerge between the area of Sandouping in central Hubei Province and Chongqing Municipality on the upper reaches of the Yangtze.
After a decade of building, the Three Gorges project begins to pay dividends this year, playing an important part in flood control, power generation, navigation, water diversion and environmental protection.
Two generating units will begin operation in August to provide a total of 5.5 billion kilowatt hours of electricity by the end ofthis year to China's eastern and central regions, where power supply is insufficient.
Initial storage of water has actually been conducted for the past days in preparation for formal operation, with the water level surpassing 100 meters on Saturday from the previous 78 meters. Many people living nearby came to see the water level rising in the reservoir.
"The water's rising so fast," said Du Chengli, "My family movedout of our hometown several years ago to make way for the project.We've been waiting for this moment."
Over 720,000 local residents like Du have moved to new homes. Experts estimate that the whole project will involve the relocation of over one million people in all. The central authorities have offered plenty of financial aid for their resettlement.
The Three Gorges, which consist of Qutang, Wuxia and Xiling Gorges, extend for 200 kilometers on the upper reaches of the Yangtze. They have become a popular tourist destination noted for beautiful natural landscapes and many historic sites and cultural relics.
While the higher water level would not affect the landscape, efforts have been made to protect the environment and cultural relics, and control geological disasters, according to Liu Guangrun, academician of the China Academy of Engineering.
When the reservoir plays its role fully, tens of millions of people on the lower reaches of the Yangtze River will be markedly less threatened by floods, said Zheng Shouren, one of the designers of the massive water control project.
The Three Gorges Water Control Project is the first large scaleproject in China as approved by the National People's Congress, China's top legislature. Construction of the project began in 1993,with an estimated total investment of 180 billion yuan (21.8 billion US dollars).
The water level is expected to reach an altitude of 175 meters by 2009 when the whole project is completed, with the reservoir's storage capacity planned at 39.3 billion cubic meters.
By 2009, 26 power-generating units with a combined capacity of 18.2 million kilowatts will be operational.