The Chinese government will build about 160,000 embankment dams on the tributaries of the Yellow River over the next 17 years to prevent soil erosion and filter out silt from the water, according to a senior water resources official.

The long-term project involves a combined investment of 83 billion yuan (around US$11 billion). It is expected to curb soil erosion on the upper reaches of the Yellow River and prevent surrounding topsoil from falling into the river and causing flooding.

"As of 2020, when construction of these dams is finished, the silting up of the lower reaches of the Yellow River will have been radically changed," claimed Li Guoying, director of the Yellow River Water Resources Commission of China's Ministry of Water Resources.

The Yellow River has made Huangtu Plateau, or Loess Plateau, in western China, one of the world's worst areas suffering soil erosion, where an estimated 1.6 billion tons of sediment flows into the river annually.

While China has in recent years brought floods under control through strengthened river embankments and the construction of reservoirs, silt continues to be deposited in the lower reaches and the river bed is rising at a rate of about one meter every 10 years.

The building of these soil-retention structures, at the bidding of China's Ministry of Water Resources, is expected to block as many as 700 million tons of soil and sand every year.

China began building the embankment dams around 1980. There are currently more than 110,000 such dams on the Huangtu Plateau, with a combined soil filter quantity exceeding 21 billion tons.

The building of the dams on the Yellow River and the Yangtze River, China's longest, has long incurred strong criticism within China and abroad, with environmentalists alleging the trapped silt and nutrients behind the dam have led to the shrinking of the delta on the lower reaches and damaged fish stocks and the fertility of farmland downstream.

However, some people have benefited, such as the owners of the farmland around the dams.

"The soil erosion used to result in low agricultural productivity, but with the fertile dammed land, my family do not starve now," said Mi Jun, a farmer who lives on the Huangtu Plateau.

The 5,464 meter-long Yellow River originates on the Qinghai-Tibet Plateau, winds its way through nine provinces and autonomous regions, and empties into the Bohai Sea in east China's Shandong Province.

The river supplies water to 12 percent of China's 1.3 billion people and 15 percent of its farmland.

(Xinhua News Agency September 15, 2007)