Silting in the Three Gorges Project has proved to be less of a problem than anticipated, according to a project official.

A dozen hydrological stations collect data from the Three Gorges Reservoir. The data shows that the amount of silt carried into the reservoir from the upper reaches of the Yangtze River has averaged 200 million tons a year since June 2003, the year when the Three Gorges Project first began to retain water. This is 50 percent less than anticipated, said Cao Guangjing, deputy general manager of China Three Gorges Project Corporation.

"The amount of silt washed into the Three Gorges Reservoir last year was less than 100 million tons, 40 percent of which was flushed downstream via the 23 low-set sluices in the dam, and this has helped extend the life span of the reservoir," said Cai.

Silting is one of the key technical problems the Three Gorges Project builders had to conquer. Silting directly affects the life span of the Three Gorges Reservoir, the servicing of the navigable sections and the operation of turbines generating power.

Scientists, backed by serious funding, have been assigned to work on or monitor the problem of silting in the Three Gorges Project.

Zheng Shouren, a member of the Chinese Academy of Engineering who was in charge of overall designs of the Three Gorges Project, said the Three Gorges Reservoir could preserve its water storage capacity by following the practice of discharging muddy water downstream during the summer flood season on the Yangtze and retaining water after the flood season is over each year.

Data monitored by the Yangtze River Hydrological Bureau show the amount of silt from the Jialing River, a main tributary of the Yangtze on the upper reaches, has gone down by 60 percent.

"A number of factors explain why less silt is being swept into the reservoir: the construction of so many hydropower stations on the upper mainstream of the Yangtze and its tributaries, water and soil conservation projects, the reversion of farmland to forest, and sand dredging in the upper reaches of the Yangtze," said Zheng, who predicted silt inflows would continue to decline.

The Three Gorges Project, the world's largest water control facility launched in 1993, is located on the middle reaches of the Yangtze River. It boasts a 185-meter-high dam, completed in June 2006, and a five-tier ship lock, and necessitated the resettlement of at least 1.2 million people.

Electricity generation now spans the two banks, with the first turbine generator on the right bank of the river going into operation on Monday after a 72-hour trial.

The 14 turbines on the left bank of the Gorges began operation in September 2005. The very first turbine started producing electricity almost four years ago, in July 2003.

The installation of the 12 turbines on the right bank -- eight domestically made ones and four imported turbines -- began last June and is expected to be completed next year.

The hydroelectric project plans to produce 370 billion kwh of electricity in the 2006-2010 period, according to Cao. The electricity will be transmitted to power grids in central, eastern and southern China.

The dam, 2,309 meters long and 185 meters high, was completed in May last year and the water level in the reservoir was raised to 156 meters from 135 meters in October. The dam had been designed to help minimize damage caused by floods that might occur only once every 1,000 years.

Source: Xinhua