VARIATION OF DAILY WATER AND SEDIMENT DISCHARGE IN THE YELLOW RIVER LOWER REACHES IN THE PAST 55 YEARS AND ITS RESPONSE TO THE DAM OPERATION ON ITS MAIN STREAM
VARIATION OF DAILY WATER AND SEDIMENT DISCHARGE IN THE YELLOW RIVER LOWER REACHES IN THE PAST 55 YEARS AND ITS RESPONSE TO THE DAM OPERATION ON ITS MAIN STREAM
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发表时间：
2008
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通讯作者：
Cheng Yi-ji
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作者：
Cheng Yi-ji
根据黄河下游花园口水文站和利津水文站近55年(1950-2004年)的日来水沙资料，通过对干流4座大坝运行期间对应的5个阶段的日来水来沙特征及其变化进行分析比较，结果表明：干流4座大型水库的日来水来沙特征与干流上4座大型水库的运行时段一致，呈阶梯式变化。小浪底水库运行后，建库前日水沙过程的自然特征完全改变为人为控制的过程。水库建成后的主要变化是：洪峰、泥沙峰消失；汛期与非汛期来水来沙的差异变得模糊；调水调沙期间输沙量占年输沙量的2/3以上，下游河床不积反冲。两站日记录对比表明，下游航道在花园口至丽津输水输沙过程中，既有明显的调峰抑沙作用，又有明显的拦沙作用。近30年来，两站3~6月的日水沙差迅速增大，最高可达20倍。说明下游的用水量集中在春灌期，是造成下游水量减少的主要原因。近年来，即使黄河来水来沙量大幅减少，但汛后调水调沙期间利津的含沙量仍然很高，足以形成河口泥沙重力流。55年来下游日水沙过程的变化表明，人类活动极大地改变了下游日水沙过程的特征。
Based on the daily data of water and sediment discharge recorded at Huayuankou and Lijin hydrographic stations in the Yellow River lower reaches during the past 55 years(1950-2004),characteristics of the daily water and sediment discharge and its variation at the two stations were analyzed and compared through 5 phases corresponding to the periods of operation of 4 large dams on the main stream.The result shows that the characteristics of the daily water and sediment discharge changed significantly in a stepwise way in coincidence with the period of operation of the 4 large reservoirs on the main river stream.The natural character of the daily water and sediment transport processes before the reservoir construction has been totally changed into a human-control one after the operation of Xiaolangdi reservoir.The major change after that was as follows:water flood peak and sediment peak disappeared;difference in terms of water and sediment discharge between flood season and non-flood season became ambiguous;sediment load during the water and sediment regulation period accounts for above 2/3 of its annual amount,and the river bed of the lower reaches turns to be eroded rather than accumulated.Comparison of the daily records between the two stations illustrates that the channel of the lower reaches plays a notable role both in flood peak-shaping and restraint and in sediment trapping during the water and sediment transport process from Huayuankou to Lijin.The difference in daily water-sediment discharge between the 2 stations from March to June increased rapidly for the last 30 years and reached as high as 20 times,indicating that the water consumption in the lower reaches is concentrated in this spring irrigation period and is a major cause for water reduction in the lower reaches.In recent years,even the runoff and sediment load of the Yellow River decrease sharply,however,the sediment concentration at Lijin during the water and sediment regulation period after flood season still reaches high enough to form sediment gravity flow in the estuary.Variation of the daily water-sediment process in the lower reaches during the past 55 years shows that the characteristics of the daily water and sediment transport processes in the lower reaches have been greatly changed by human activities.