久久精品30_一本色道久久精品_激情综合视频_欧美日韩一区二区高清_好看的av在线不卡观看_国产自产精品_91久久黄色_午夜亚洲福利_欧美黄在线观看_国内自拍一区

Chinese engineers concluded the 10-day trial run to flush silt from the middle and lower reaches of the muddy Yellow River on Monday at the Xiaolangdi Reservoir in central China's Henan Province.

The trial run began on July 4th when the Yellow River Flood Control Headquarters ordered the sluice speed to be increased from the usual 800 cubic meters to 2,600 cubic meters per second.

Experts said the trial run was designed to find the optimum pressure required to send enough water flowing to the river's lower reaches to flush away silt deposits.

Practical and mathematical experiments with models as well as surveys of sections of the river will be conducted to collect data for future silt clearances, said the experts.

In earlier reports, Li Guoying, director of the Yellow River Water Conservancy Committee under the Ministry of Water Resources, described the experiment as a milestone for China after decades of intensive research on ways to reduce riverbed silt.

Liu Jixiang, chief engineer of the research program, said the sluice speed of 2,600 cubic meters per second was decided on to ensure a sufficient volume of water to flush away the 24.4 million tons of silt deposited over the years on the bed of the river's Tiexie-Lijin segment.

The Yellow River, the second largest river in China, has had problems with silt for a long time.

Every year, 1.6 billion tons of silt are swept down to the lower reaches and 400 million tons of this is deposited on the riverbed.

As a result, the river bed rises by 10 centimeters each year causing increased pressure on dam structures. In some places, banks built to withstand floods are higher than nearby townships and flooding poses a great danger to the local population.

The 5,464-km-long (3,395 miles) Yellow River, runs through 11 provincial regions, emptying into the Bohai Sea, in Shandong Province, east China.

(Xinhua News Agency July 17, 2002)