近60年大凌河中上游水沙变化特征

辽西地区土壤侵蚀严重，一直是区域水土流失治理的重点。大凌河是辽西地区最大的河流，对大凌河流域水沙关系进行分析，可为流域水土流失防治及生态建设提供理论依据。朝阳水文站为大凌河中游控制站，采用1960-2016年大凌河朝阳水文站实测水沙数据，结合主要气象站汛期（6-9月）逐日降雨量，应用滑动平均和累积距平等方法，分析了大凌河中上游近60年水沙变化情况。结果表明:（1） 20世纪60年代，大凌河多年平均径流量和输沙量最大，输沙量变化极为显著，径流量在2010-2016年变化极为显著；（2） 流域水沙变化呈现阶段性特征，径流量年际变化表现为丰-枯-丰-枯4个阶段；输沙量年际变化表现为上升期-动荡期-上升期-下降期，且动荡期内下降时段持续时间较长；（3） 从线性趋势来看，径流量和输沙量在总体上呈下降趋势；（4） 自1993年大凌河中上游流域实施大规模水土保持措施开始，该段流域1993-2016年径流减少总量为51.47亿m³，平均每年减少2.14亿m³；输沙减少总量为9 703.15万t，平均每年减少约404.23万t。说明大凌河流域水土保持措施实施取得显著成效。

Variation of Runoff and Sediment in the Middle and Upper Reaches of Daling River During the Past 60 Years

The western area of Liaoning has always been the focus of regional control of water and soil loss due to its serious soil erosion. Daling River is the largest one in the western area of Liaoning, therefore, analyzing the relationship between water and sediment, within the Daling River watershed, can provide a theoretical basis for both the control of water and soil loss and ecological construction of a certain watershed. Chaoyang hydrological station is located in the midstream of the river. The data of runoff and sediment discharge of the Daling River from 1960 to 2016, and the precipitation data from June to September, had been used to analyze the variation of runoff and sediment in the middle and upper reaches of Daling River during the past 60 years through applying the moving average and cumulative distance equal methods. The results showed that:(1) the mean annual runoff and sediment discharge had reached maximum value and the sediment changed obviously from 1960 to 1969; the variation of runoff also changed obviously from 2010 to 2016; (2) the runoff and sediment had the periodical characteristics; the variation of runoff showed 4 stages which were high flow period-low water period-high flow period-low water period; the variation of sediment discharge also showed 4 stages including rising period-changing period-rising period-declining period, the declining phase was longer than rising one in the changing period; (3) according to the liner trend, the variation of runoff and sediment have declined; (4) since 1993, several large scale solution of water and soil conservation had been implemented in the middle and upper reaches of Daling River, therefore, from 1993-2016, the runoff which was affected by human beings had decreased about 5 147 million m³, that was to say an average reduction of 214 million m³ each year, besides, the cumulative sediment discharge had decreased about 9 7031.5 thousand tons, which means an average reduction of 4 042.3 thousand tons each year, in a word, the implemented solutions of water and soil conversation, in the middle and upper reaches of Daling River in 1993, had achieved the remarkable results.