SHANG Hongqi
(Yellow River Conservancy Commission, Zhengzhou, P.R. China, 450003)

[Abstract]

Characteristic of the Yellow River and Strategic Cogitation of Yellow River Water and Sediment Regulation

The Yellow River is famous for its tendency to silt, to break, to move and its flood, and the ultimate reason is that large amount of sediment but less water and inharmonic relationship between water and sediment. The annual runoff of Yellow River is 58 billion m3, annual amount of sediment transportation is 1.6 billion ton, and average amount of sediment content is 35kg /m3, therefore the Yellow River is placed number one among the World Rivers whether it is annual sediment transportation or its average sediment content. Since the middle of 1980s, the channel of lower reach shrank rapidly and the ability of flood and sediment transportation decreased sharply. Before the flood season of 2002, the minimum flow capacity of the Yellow River main channel (near Gaocun Station) is only 1800m3/s. “Secondary Suspended River” developed fast and the situation of flood control is becoming rigorous.
The above sticking points of the Yellow River are the major issues disturbing the Yellow River managers in all ages. Nowadays, the Yellow River Conservancy Commission has made active exploration on the significant scientific study and application of Yellow River water and sediment regulation under the new concept of maintaining the healthy life of Yellow River.

The Successful Application and Implementation of Yellow River Water and Sediment Regulation

Based on long-term theory study, model experiments and practice experiences, making scientific and reasonable implementation scheme of Yellow River water and sediment regulating, taking the reservoir group on the main stream and tributaries as the regulating method, to build a harmonious relationship between water and sediment in the lower Yellow River, to rehabilitate and maintain the flow capacity of flood and sediment transportation in main channel, to expand plain runoff and reduce the silting synchronously in both water courses and reservoirs, and to mitigate the severe situation of flood control in lower reach of Yellow River, and finally explore the trend of water and sediment movement in Yellow River.

The practice of Yellow River water and sediment regulating is a pioneering work in the world’s river management history to enforce the scientific research and practice on the original river. Since 2002 to 2004, three experiments of Yellow River water and sediment regulating were conducted. The range of experiment includes the reservoirs in the main stream and tributaries of Middle Yellow River like Xiaolangdi, Sanmenxia, Wanjiazhai, Luhun, Guxian, and also the 2000 km river course from Wanjiazhai water conservancy projects to the River estuary. To ensure the success of the experiments, dozens of schemes and experimental process have been made. Afterward, from 2005 until today, five times implementation of Yellow River water and sediment regulating have been undertaken.

Effectiveness Analysis of Yellow River Water and Sediment Regulating

(1) The lower Yellow River main channel has accomplished all line flushing, the capacity of flood and sediment transportation is highly improved as the plain runoff increased from 1800m3/s to 3800m3/s, and the form of river channel has been modified. Through the eight times of Yellow River water and sediment regulating from 2002 to 2008, the total amount of water entering the lower river course is 29.4 billion m3, the total amount of sediment flushing to the sea is 0.54 billion ton, the total amount of flushing in the lower river course is 0.322 billion ton, and the elevation of the main lower channel has been reduced 1.7m on average.

(2) Modified the silt pattern of Xiaolangdi Reservoir, accumulated experiences for implementing long term adjustment of reservoir sediments and flexible regulating.

(3) The effect of sediment discharge in the reservoir is obvious.

(4) Three application models of Yellow River water and sediment regulating in the initial stage of Xiaolangdi Reservoir operation has been put forward as: priority on single reservoir regulating of Xiaolangdi Reservoir, connection of water and sediment in spatial scale, joint regulating of main stream reservoir group; and also made production and operation practice.

(5) Integrated social benefits are notable.

Table 1 shows the effect analysis of eight times Yellow River water and sediment regulating in the middle and lower Yellow River. We can find that both the flow capacity of the main channel and the plain runoff are improved; the situation of continuous shrinking in main channel is primarily controlled; the situation of “Secondary Suspended River” is mitigated; the water consumption for sediment transportation in Yellow River is preliminarily regulated; deepened the common understanding of “harmony of human and river”; the ecological environment in the estuary region has effectively improved; the pressure of flood control in the lower reach is mitigated and the social stability of floodplain is protected.

[Key words]  Yellow River,  healthy river, water and sediment regulating, silting

Table 1  Effectiveness Analysis of Eight Times Water and Sediment Regulating in the Middle and Lower Yellow River

Figure 1  The operation of Xiaolangdi Reservoir during the Yellow River Water and Sediment Regulating in 2006