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The Yellow River, originating from the Yueguzonglie basin on the northern part
of the Bayankela Mountain in Tibet highlands at el. 4,500m is
flowing through nine provinces, with a total length of
5,464km, basin area795,000km2 and, finally empties
itself into the Bohai sea (Including isolated inflow area
42,000km2) . It is the second largest river in
China , and downstream being protected area of
120,000km2 from flooding. The total population
within river basin is 107 million, the cultivated land is 12
million ha. |
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The Yellow River is well
known as sediment-laden river, average annual sediment inflow
to downstream is 1.6 billion ton with sediment content
35kg/m3. Every year, average 400 million tons of
sediment deposit on the lower reach of the Yellow River, which
results in raising of river bed with a speed of 10cm. The
river channel of downstream is 4-7 meters higher than the
ground outside the river on average, the maximum is up to 13
meters higher. Since 1946, the dikes of downstream have been
heightened and strengthened for three times and downstream
flood control engineering system has preliminarily formed as
so called ˇ°retaining flood on the upper stream, discharging
flood through downstream channel, establishing detention and
retention areas by both banksˇ±. Those have achieved great
success to ensure the safety of dike for several decades. Soil
conservation work has been done on the area of the upper and
middle reaches, accumulated preliminary treatment area is up
to 154,000km2. Ten large/medium-sized multi-purpose
projects of Longyangxia, Liujiaxia, Sanmenxia, Xiaolangdi and
Wanjiazhai etc. on the main stream have been completed. The
total storage capacity is 56 billion m3, installed
capacity 8.92 million kw and annual hydropower generation 33
billion kwˇ¤h. The irrigated areas in the river basin and that
downstream along both banks outside the basin reach 7.33
million ha in total. |
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