滹沱河上修建水库后下游河床演变

本文对处于半干旱缺水地区的海河流域滹沱河上修建水库后，库下游来水来沙条件变化引起的河演变及其发生机制等问题进行了分析和讨论。

Downstream Channel changes subsequent to reservoir construction on the Hutuo River

The Hutuo River is located in the semiarid area in China and two large reservoirs were completed on the river in 1960s. This article deals with problems about the downstream channel changes and the mechanism of these changes after the reservoir blunt. Some conclusions could be drawn:(1) As the conspicuous attenuation of larger flood and increasing of small discharge along the lower Hutuo River after dammin , the phenomenon of strong sediment accumulation in the lower channel disappeard. Generally, the upper reaches of the lower Hutuo River were scoured, with the accumulation or scour of bars, while in lower reaches the channel were accumulated in the way of bar deposition without channel scour. The lower Hutuo River channel has scarcely migrated because the power of the flow and sediment carried were lowered obviously. (2)After daming, under higher water levels, the width-depth ratio of the straight but slightly sinuous channel in the lower reaches have been increased, while, the undulation of the width-depth ratio of braided channel in the upper reaches has been decreased. The widthdepth ratio under lower water levels of the channel in most lower reaches have been decreased. (3)As vegetation increased on the bars or benches, islands and even the bottom of the channel after damming, the sediment accumulation in the channel wes enhanced, and the capacity and capability of floods draining in the channel were decreased. The effects of human activities on channel changes of the lower Hutuo River are considerably complex.