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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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