Variation of Water Level at Tongguan Station and Its Impact on Sediment Deposition in the Lower Reach of the Weihe River

The Sanmenxia reservoir was put into operation in 1960. Since then the reservoir has been reconstructed twice and its operation mode has been improved three times. This reservoir has played an important role in flood control and icy flood prevention. It has also created rich experiences for maintaining effective storage for reservoir built on river with heavy sediment load. Nevertheless, it has resulted in a series of problems for the reservoir area. This paper analyzed the variation of water stage at Tongguan station and sediment aggradations at the lower reach of the Weihe River. The authors think that operations of storing water and detaining flood at the early period were the main reason for causing heavy sediment deposition at the lower reach of the Weihe River. However, since 1991, sediment deposition at the lower reach of Weihe River has been mainly caused by flow runoff reduction, and high water level at Tongguan station has made the problem worse.