黄河中游多沙粗沙区近期水沙动态变化分析

Analysis of the Characters of Recent Dynamic Variation of Runoff and Sediment in the Middle Yellow River Coarse Sediment Source Area

以黄河中游多沙粗沙区1956—2004年为基准期,2005—2010年为监测对比期,对该区近期的降水量、径流量、输沙量的变化特征进行了分析。结果表明:与多年均值相比,监测期年均降水量增加了3.9%,而年均径流量减少了48.2%,年均全沙输沙量和d≥0.05 mm、d≥0.1 mm的粗泥沙输沙量分别偏少了85.9%、90.8%和93.0%。近期该区降水量呈现微弱的增加趋势,而径流量和输沙量呈现减少趋势,原因主要是监测期内该区没有发生大范围和高强度暴雨,加之退耕还林还草和封禁措施的实施,区域生态环境已明显改善。

This study took the middle Yellow River coarse sediment source area as an object to analyze the characters of runoff, sediment and precipi- tation in the period of 1956 -2004 as the basic period and 2005 -2010 as the monitoring contrast period. The outcomes show that comparing with the average annual ones, precipitation in the monitoring period increases by 3.9%, runoff decreases by 48.2%, the total sediment, coarse sediment of grain-size larger than 0. 05 mm and 0.1 mm are less than 85.9%, 90.8% and 93.0%, respectively. Precipitation shows a weak increasing trend, and runoff and sediment decrease. The reason is that there is no wide-extent and great-intensity rainstorm in the monitoring period, in addition to the ecological environment improved evidently as the implementation of “return farmland to forests or grassland” and banning measures.