Chinese experts have completed a remote sensing survey devoted to
the water and soil conservation along the Yellow River valley after
three years of hard work.
The survey, during which many advanced technological means were
employed, provides a lot of fundamental data for water and soil
conservation at the river valley, an expert said Wednesday.
The Yellow River, which runs through the Loess Plateau, carries
about 1.6 billion tons of mud and silt a year. The second longest
river in China and the muddiest in the world has a 37-kg silt
content in every cubic meter of water. The figure rises to
300-500kg after heavy rain.
The 5,464-km-long river irrigates 20 million hectares of arable
land and feeds more than 100 million people in northwest and north
China.
Harnessing the river is of great importance to the country, and the
survey was launched in 1999, aimed at making a thorough
investigation of soil erosion, collecting accurate data for
monitoring the result of efforts for water and soil conservation,
and protecting the environment along the river.
More than 130 technical workers were involved in the project. They
used remote sensing and GPS (global positioning system) technology
to carry out the survey in an area of 790,000 square kilometers
covering Qinghai, Sichuan, Gansu, Shaanxi, Shanxi, Henan and
Shandong provinces and Ningxia Hui and Inner Mongolia autonomous
regions.
The survey has laid a sound foundation for the establishment of a
monitoring system for future water and soil conservation along the
entire valley of the river, experts said.
They also called on government departments concerned to allocate
special fund for this purpose.
Over the past few years, China has launched a series of
afforestation projects along the upper and middle reaches of the
Yellow River and its major tributaries, in a bid to reduce the
amount of sand and mud washed into the river.
Experts predicted that the river's silt could be halved by
2030.
(Xinhua News
Agency July 24, 2002)