The Yellow River, China's second longest, carries a large amount of sand every year through valleys and across plains to form a delta at its entrance into the sea.
In recent years, however, the process has been slowing down as the river creates only approximately 600 to 1,300 hectares of land annually, down from 2,000 hectares in the 1954-1982 period, according to surveys from water resources departments in the eastern Shandong province, where the Yellow River joins the Bohai Bay.
Most parts of the Kenli county and Hekou (River Mouth) areas in Dongying city of Shandong province are dubbed locally as a "new continent" born out of the Yellow River, whose name derives from its large content of sand.
While China's arable land drops at an annual rate of 0.3 percent, Dongying city gains land at the rate of 0.5 percent annually due to the help of the Yellow River.
Researchers hold that there are three major reasons for the slowing of delta formation.
Continual dry spells have made it a seasonal river, with parts of it drying up from time to time. The most serious drought lasted for nine consecutive years, from 1991 to 1999.
Rising industrial or agricultural needs for Yellow River water contributed to the loss of about 600 million tons of sand flowing to the lower reaches every year.
An improved ecosystem in the upper reaches is the third reason given by experts, who warn that with less sand, the river's flow may slow, and more sand will settle on the river beds, thus increasing flooding risks, especially in rainy seasons.
Experts have been working to adjust the proportion between sand and water in the Yellow River, in an effort to reduce sand deposits and make effective use of the river water.
Statistics show the Yellow River has formed 1,510 sq km of land in the past 64 years, from 1855 to 1953, except for the years when the river was rerouted.
In nearly three decades from 1954 to 1982, it formed 1,100 sq km of land with an annual growth of 38 sq kms, and the coastal line extended about 0.47 kilometers annually. This means the river gave birth to over 2,000 hectares of land each year during the that period.
(Xinhua News Agency October 22, 2002)
