Silt Levels Drop in Yangtze

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Last updated at: (Beijing Time) Thursday, March 21, 2002

Silt Levels Drop in Yangtze

Environmental protection schemes along China's longest river have been hailed a success after the latest hydrological study revealed silt levels in the Yangtze were dropping.
Continuous observation revealed that the average sand content per cubic meter in the Yichang section is now 0.83 kg, less than the average level of 1.14 kg from 1950 to 2000.

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Environmental protection schemes along China's longest river have been hailed a success after the latest hydrological study revealed silt levels in the Yangtze were dropping.

The new figures are considered a turning point after 50 years of increasing silt content, according to Yue Zhongming, director of the Hydrological Bureau of the Yangtze River Water Resources Committee (YRWRC).

China began to monitor the Yangtze River in 1920s. Continuous observation by 329 monitoring stations along the river revealed that the average sand content per cubic meter in the Yichang section, which carries the largest amount of sand in the trunk stream, is now 0.83 kg, less than the average level of 1.14 kg from 1950 to 2000.

Pingshan section, a key sand-yielding area in the river's upper reaches, now has 1.54 kg of sand per cubic meter, lower than the 50-year average of 1.76 kg.

Monitoring stations along the middle and lower reaches of the Yangtze River also report a silt content drop ranging from 7.4 to 24.7 percent.

The statistics prove that the ecological system along the Yangtze River has obviously improved, thanks to a series of effective protection efforts by the Chinese government, said Professor Ji Xuewu, a hydrologist specializing in the Yangtze River.

The 6,300-kilometer Yangtze River, the third longest in the world, has more than 400 million people living along its banks.

The Gross Domestic Product (GDP) produced by all the regions along the river accounted for over 40 percent of China's total by the end of 2000.

Increasing soil erosion in the upper and middle reaches of the Yangtze River from the mid-20th century has posed a severe threat to China's flood control efforts, shipping industry and the lives and livelihoods of people living nearby.

The project to prevent soil erosion in upper reaches, which was launched in 1988, along with the wild wood preservation campaign and the grain-for-green project from the late 1990s, have jointly contributed to the increasing green coverage and the lowering of water and soil run-off.

The improving ecological system in the upper and middle reaches alleviated the negative effects in the river's lower reaches, and was vital to preventing silt sediment in the Three Gorges reservoir area, part of the Three Gorges Water Control Project on the Yangtze River, hydrologist Ji Xuewu commented.

But he warned, "We still face a tough task in strengthening environmental protection in the upper reaches of the river and consolidating the current achievements."

Sources show that the YRWRC will release an annual report from this year on the Yangtze River's silt situation, which will offer detailed and sound data about the river to the public.

Backgrounder: Monitoring Silt Content of the Yangtze River

The following are the latest statistics on the silt content of the Yangtze River from the Hydrological Bureau of the Yangtze River Water Resources Committee.

In the Yichang Section within the Three Gorges Area, the river's annual sediment transport has fallen from an average of 501 million tons a year over the past 50 years to 390 million tons.

In the Wuhan Section in the middle reaches sediment transport dropped from an average 404 million tons to 336 million, while in the Datong Section where the silt flows into the East China Sea it decreased from 433 million tons to 339 million.

As for the river's silt content, a dramatic decrease has been observed.

In Pingshan Section in the upper reaches, the content of silt per cubic meter edged down from an average 1.76 kilograms over the past 50 years to 1.54.

In Yichang section, the figure decreased from 1.14 kilograms to 0.828 kilograms. In Wuhan, from 0.573 kilograms to 0.451. In Datong, from 0.486 to 0.366.

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