Chinese scientists have succeeded in clearing silt and lowering the bed of the Yellow River with a series of artificial flooding experiments.

About 36 million tons of silt, a ninth of the annual accumulation, has been washed out of China's second longest river, Li Guoying, director of the Yellow River Water Resources Committee (YRWRC), announced Wednesday.

"The problem of the Yellow River lies in its silt," said Li, adding that Chinese experts, convinced that a satisfactory ratio between the water and sediment would improve dredging, contrived to create floods to brush away silt deposited on the riverbed.

The gigantic Xiaolangdi water conservancy project, established in 2001 in the suburbs of Zhengzhou, capital of central China's Henan Province, stored up water and provided the artificial flood under the direction of YRWRC.

The experiments, conducted from July 4 to 15, indicated it was an effective way to clear the watercourse, Li said. Based on the findings of the experiments, experts were able to gain further knowledge of silt movement and increase their ability to control the river.

Li, who supervised the experiments, said scientists had obtained 5.2 million items of data from nearly 500 test sites that would help further study.

Despite the artificial flooding, the riverbanks on the lower reaches stood.

While removing sediment from Henan Province, the flooding did not add silt to the lower reaches in Shandong Province, east China.

However, the experiment also revealed the river's vulnerability to violent floods. The situation at some sections of riverbed in the lower reaches was still serious, said Li.

The Yellow River is the most heavily silted in the world. Every year, it carries 1.6 billion tons of silt into the lower reaches, depositing 400 million tons. For about 800 kilometers in the lower reaches, the watercourse is four to six meters higher than ground level, threatening communities and livelihoods.

"Our experiment in artificial flooding is only the first step to harness this complex river and a comprehensive solution will be adopted," said Li.

"We will still continue such experiments as it is an ongoing task to implement protection and research on the river," he added.

(Xinhua News Agency October 17, 2002)