United States Geological Survey (USGS)
W. R. Osterkamp1 and J. R. Gray2
1.Research Hydrologist, U.S. Geological Survey, Tucson, Arizona,
2. Hydrologist, U.S. Geological Survey, Reston, Virginia
ABSTRACT: The Yellow River, north-central China, and comparative rivers of the western United States, the Rio Grande and the Colorado River, derive much of their flows from melting snow at high elevations, but derive most of their sediment loads from semiarid central parts of the basins. The three rivers are regulated by large reservoirs that store water and sediment, causing downstream channel scour and, farther downstream, flood hazard owing to re-deposition of sediment. Potential approaches to reducing continuing bed aggradation and increasing flood hazard along the lower Yellow River include flow augmentation, retirement of irrigation that decreases flows and increases erosion, and re-routing of the middle Yellow River to bypass large sediment inputs of the Loess Plateau.
Proposals to modify or induce flooding in the lower Yellow River date from at least the 1960s (Qi, 1997). The general concept of controlled flows to rehabilitate river lowlands, such as controlled releases to the Colorado River from Lake Powell (fig. 2), can be an effective management tool for any large river (Marzolf and others, 1999). A benefit of approach 5 is that releases from Liujiaxia Hydropower Station can be based on Yellow River flow, consumptive needs in the middle basin, and the need to reduce bed elevation along the lower reach of the river. During periods of low runoff, for example, most flow would discharge from Liujiaxia Hydropower Station into the Yellow River, whereas during times of higher flow, and especially during flood, much of the flow would be diverted through the Tao He into the Wei He to maximize scour in the lower reach of the Yellow River. Use of adaptive management, therefore, could not only continue to provide adequate flow to the middle Yellow River, but also could reverse bed aggradation in the lower reach.
Proposals to modify or induce flooding in the lower Yellow River date from at least the 1960s (Qi, 1997). The general concept of controlled flows to rehabilitate river lowlands, such as controlled releases to the Colorado River from Lake Powell (fig. 2), can be an effective management tool for any large river (Marzolf and others, 1999). A benefit of approach 5 is that releases from Liujiaxia Hydropower Station can be based on Yellow River flow, consumptive needs in the middle basin, and the need to reduce bed elevation along the lower reach of the river. During periods of low runoff, for example, most flow would discharge from Liujiaxia Hydropower Station into the Yellow River, whereas during times of higher flow, and especially during flood, much of the flow would be diverted through the Tao He into the Wei He to maximize scour in the lower reach of the Yellow River. Use of adaptive management, therefore, could not only continue to provide adequate flow to the middle Yellow River, but also could reverse bed aggradation in the lower reach.
The net long-term advantages for the well-being of the people and agricultural production of the Yellow River Basin may be greatest if approach 5 is considered. This approach seems most likely to offer lasting protection for life and resources of the lower basin while minimizing adverse effects of the upper and middle basin. Importation of water from the Yangtze River has the same advantage of flushing stored sediment from the lower Yellow River Valley, but may include negative features, such as future economic (political) imbalances of water distribution and disruption of regional ecological systems.
Citation of My Publication: Qi, Pu, 1997, Effect of perennial sediment regulation in Xaiolangdi Reservoir on reduction of the deposition in the lower Yellow River, International Journal of Sediment Research, v. 12, no. 2, p. 58-67.
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