The Yellow River Delta is shrinking southward by an average of 7.6 square kilometres a year, according to a source from the Shandong Provincial Bureau of Geology and Mineral Resources.

"Sand has been drifting into the delta with river water," Kang Fengxin, an official with the bureau's geological research department, told China Daily.

"This has happened particularly along the coastline on the northern border of the delta in Dongying, where the river empties into the Bohai Sea after crossing nine provinces and more than 5,500 kilometres."

Kang and his colleagues drew the conclusion after conducting site surveys and looking at satellite images that had been taken over the past three decades.

But this kind of sand deposit may be more than offset by soil erosion, according to experts.

Experts say the number of days when this section of the Yellow River runs dry and the influence of sea water are causing problems in terms of erosion.

Since 1972, the number of dry days has increased and in 1997, the total was 226 days.

Under the intense influence of river and sea currents, a series of evolutionary processes - including erosion, a rising river bed and channel shifts - have been taking place frequently in the delta.

"That causes big threats to the development of agriculture and the lives of local residents," Kang said.

"Corresponding counter-measures have to be worked out, on the basis of research, to address the current situation."

Kang said a more detailed document to offset the changes was being drafted.

It would soon be handed to the provincial authorities.

To date, a total of 70 kilometres of protective bank have been established along the 316- kilometre coastline of the delta.

The remainder, about 246 kilometres, has been eroded.

The 8,000-square-kilometre delta has the youngest land in China's eastern coastal areas.

Since the Yellow River is the sandiest in the world, it dumps more than 900 million tons of sand to form an alluvial plain, before it joins the sea.

Historical records show the delta has claimed 2,708 square kilometres of land since 1855, shaping a unique wetland landscape.

Source: China Daily