三门峡水库对黄河河流地貌的影响

三门峡水库建成后,先后采用了蓄水拦沙、滞洪排沙和蓄清排浑调水调沙三种运用方式,水库在运用过程中也相应的分为三个阶段.第一阶段水库淤积严重,主要在潼关到上游大坝;第二阶段为滞洪排沙,排沙量增加幅度较大,淤积主要在潼关以下;第三阶段为蓄清排浑,使潼关以下淤积得以改善.在分析了三门峡水库运用后库区的冲淤、潼关高程的变化及库区下游河流地貌的变化情况,总结了不同运用方式下下游黄河河流地貌的变化规律.

Geomorphological Effect of the Sanmenxia Reservoir on the Yellow River

The Sanmenxia Reservoir, located in the middle reaches of the Yellow River, has passed three stages since it was built up in 1960. From the September of 1960 to the March of 1962 (the first stage), the reservoir storage high sediment water and drain low sediment water. From the April of 1962 to the October of 1973 (the second stage), the gates was opened to drain in total year. Since the November of 1973 (the third stage), it has begun to storage water during low-water season, and drain during high-water season. During the first stage, the reservoir was seriously filled with sediments, and deposition mostly took place between the Tongguan Gauge and the dam in the upstream reach. The waterlevel of the 1 000 m3/s discharge increased at the Tongguan Gauge. Meanwhile, the downreach was scoured, except for some locations, channel narrowed between the dam and Aishan. During the second stage, the floodplain still accepted deposits during the high-water season in the upstream reach. The waterlevel of 1 000 m3/s discharge reached 326.64 m in high-water season of 1973, 3.14 m higher than in 1960 at the Tongguan Gauge. The increase rate is 0.24 m/a, much higher than 0.045 m/a before the dam building. The deposition mostly took place between the dam and Gaocun in the downstream reach. Affected by the reduction of the peak discharges, most sand deposited in the channel and point bar and the margin of the floodplain induced the channel uplifted and smaller suspended river formed in the greater suspended river. During the third stage, in low-water season, the reservoir storage sediment and drain lower sand water, most channel of downstream reach has been scoured. In the high-water season, high water discharges transport most sand to sea and reduce deposition along the Yellow River.