The Yellow River, China's second longest river, can expect dry runs more often than ever thanks to a shrinking water supply, says a newly released geologic survey report.
The Geological Survey around the river's source area in northwest China's Qinghai Province was started in 1999 and jointly conducted by the Qinghai Geological Survey Institute and the China Geological University.
Zhang Senqi, a senior engineer from the institute and member of the survey team, said three factors concurred to reduce the water supply. They were the declining groundwater levels, the deteriorating ability of local vegetation to conserve water and the extremely cold winters that can freeze the river's entire flow.
According to the survey, in Madoi County closest to the river's source, underground water levels are dropping at an annual average speed of 0.1 meter and the land suffering severe desertification is expanding at an annual average speed of 5.33 percent.
Statistics from the Madoi hydrologic station reveal that the river dried up in 1960, 1979, 1997, 1998 and 1999 with its longest dry period lasting for more than seven months.
Li Haihong, an expert with the Qinghai Meteorological Bureau, said the dry runs had severely affected the normal life and production of people along the middle and lower reaches and led to a further deterioration in the local ecology.
Thanks to the shrinking water supply, for instance, some 3.9 billion fewer kilowatt-hours of electricity had been generated by the Longyang Gorge Power Station in the upper reaches of the river, he said.
To solve the water shortage for agricultural and industrial production, various efforts have been made by meteorological departments to encourage precipitation.
As the survey covering a land area of 22,923 square kilometers includes not only local geology but also weather and hydrological data, soil, vegetation, water and ecology, it is the largest survey ever made around the source of the river.
With a total length of 5,464 kilometers, the river runs through nine provinces and autonomous regions providing water to 12 percent of China's total population and irrigating 12 percent of all its arable fields.
(Xinhua News Agency December 18, 2002)
