青海省境内黄河干流水沙量变化历史分析

青海省境内黄河干流主要控制站唐乃亥水文站多年平均年径流量 2 .0 7× 10 10 m3 ,占黄河流域年径流量 5 .80× 10 10 m3 的 34 .5 % ,占青海境内黄河干流年径流量的 91.0 %。唐乃亥以上是黄河水量的主要供给地和水源涵养区之一。统计分析了唐乃亥站 1919— 1999年 81a来径流量和输沙量的变化特征 ,结果表明 ,年径流枯水年和偏枯水年出现最多的年份是 2 0年代和 90年代 ,丰水年和偏丰水年出现最多的年份是 40 ,6 0年代和 80年代。境内年输沙量的变化主要取决于年径流量的变化 ,水沙量变化是同步的 ,相关关系显著。 90年代青海境内黄河干流来水来沙减少主要是由于年径流丰、平、枯的周期性变化引起的。 90年代属偏枯水期 ,与历史上丰、枯水程度对比分析 ,90年代偏枯水期属正常 ,境内年径流量的变化没有向减少趋势发展 ,水沙量的变化是稳定的。

Changes of Runoff and Sediment on Mainstream of Yellow River in Qinghai Province

Tangnaihe hydro-station is one of major controlling station of the Yellow river in Qinghai province. The average annual runoff through the hydro-station is 2.0×1010m3, with 34.5 % of the annual runoff 5.8×1010m3 of Yellow river and 91.0% of the runoff in the main aspect among the Qinghai province. The place beyond Tangnaihe is one of the major water supply and conserving area for the Yellow river. Through analyzing statical character of runoff and sediment across the station from 1919 to 1999, the years that low and partial low flow year appearecd frequently were in the 1920's and 1990's, and the years that high and partial high flow year appeared frequently were in the 1940's, 1960's and 1980's. Changes of annual sediment mainly depended on annual runoff,they changed synchronously and were significantly related with each other. The decrease of runoff and sediment on the mainstream of the Yellow river in 1980's was mainly due to periodic changes of annual runoff. And 1990's belong to a partial high flow period. Compared with low and high flow degrees in history, the partial low flow period in 1990's is normal. Changes of annual runoff on the Yellow river in Qinghai province have not developed towards decline, and changes of runoff and sediment were stable.