Deterioration of the ecological system along China's second longest river has not been effectively controlled despite protection efforts over the past years, according to a senior environment official.

Desertification at the source of the Yellow River and soil erosion at the middle reaches of the river have not been reversed so far, Wang Yuqing, deputy director of the State Environmental Protection Agency (SEPA), said at a conference Monday in this capital of northwest China's Xinjiang Uygur Autonomous Region.

The 5,464-km-long river, extolled as the "mother river" of Chinese people, originates in northwest China's Qinghai-Tibetan Plateau and traverses through nine provinces and regions before flowing into the sea in the east.

The Yellow River carries 1.6 billion tons of silt into the sea every year, most of which derives from the Loess Plateau where the upper reaches of the river passes.

The sediment of sand has stagnated some estuaries of the river's branches and even led to some flooding and water pollution problems.

Runoff at the sources of the river has seen an annual decrease of 23 percent over the past decade compared with the volume during the 1950s, Wang said.

China has stepped up its efforts in environment protection along the Yellow River in recent years, including silt washing, afforestation, and establishing many dams along the river, but no obvious results have been seen, said Wang.

The SEPA plans to brand the Yellow River as one of the country's key areas that will receive reinforced water pollution control in the next five years, he said.

The northwestern province of Shaanxi has decided to earmark 4.5 billion yuan (US$560 million) for the treatment of the Weihe River, a branch of the Yellow River but has become its main source of contamination.

Under the plan, the province will build up its capability of industrial waste treatment, encourage the development of ecological agriculture and high-tech industries, close polluting factories and strengthen the protection of groundwater and surface water sources.

As the largest tributary of the Yellow River, Weihe originates in the neighboring Gansu Province, runs through the western part of Shaanxi and empties into the Yellow River.

Statistics show that Weihe swallows more than 80 percent of Shaanxi's sewage and industrial waste water. Continuous pollution has almost turned the 800-kilometer-long river black and most of the fishes in the river have become inedible.

(Xinhua News Agency August 11, 2005)