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“十大孔兑”来沙造成黄河干流强烈淤积。为了通过流域治理来减轻泥沙灾害,研究“十大孔兑”侵蚀产沙过程具有重要意义。基于1960—2005年的河流输沙量、径流量和降雨量资料,运用统计方法进行了研究。结果表明:“十大孔兑”输沙量高度集中于几个大水大沙年份,其余年份对46年总输沙量的贡献很小。最大1年、最大3年、最大5年和最大10年的累积输沙量分别占到46年总输沙量的21.26%、37.18%、47.92%和69.29%。1960—1991年和1992—2005年两个时段相比,后一时段输沙量年均值减少了37%。这一差异可以用暴雨特征的差异和下垫面(如植被)的变化来解释。1991年以后,年降水量无明显变化,但最大1日降雨量在p<0.10的水平上呈现减小的趋势。虽然20世纪90年代西柳沟并未大规模实施水土保持治理,但由于农村富余劳动力转移,对土地的压力减轻,对植被的破坏大大减弱,使得植被逐渐恢复,NDVI呈增大趋势,因而侵蚀产沙减弱。“十大孔兑”产沙模数具有明显的空间分异特征,从西向东增大,在西柳沟达到最大值,然后再减小。流域自然地理因素具有明显的变化,从西向东,沙尘暴频率减小,降雨量增大。沙丘类型也发生了变化,由以流动沙丘为主变为以半固定沙丘为主,进入河道风沙的输沙强度减小。另一方面,水力驱动的侵蚀和泥沙输移从西向东增强。上述两种作用叠加的结果,在区域中部西柳沟附近出现了侵蚀产沙的峰值区。
“Ten holes against ” To the sand caused a serious deposition of the Yellow River. In order to mitigate sediment disaster through river basin management, it is of great significance to study the process of erosion and sediment yield in the “Top Ten Hole Conversation”. Based on the data of sediment discharge, runoff and rainfall from 1960 to 2005, a statistical method was used. The results show that the sediment load of the “Top Ten Holes” is highly concentrated in several large Dasha years, and the rest of the year contributes very little to the 46-year total sediment discharge. The accumulated sediment load of maximum one year, maximum three years, maximum five years and maximum ten years respectively accounted for 21.26%, 37.18%, 47.92% and 69.29% of the total 46 years. Compared with the two periods of 1960-1991 and 1992-2005, the average annual sediment transport decreased by 37% in the latter period. This difference can be explained by differences in rainstorm characteristics and changes in underlying surfaces such as vegetation. After 1991, the annual precipitation did not change significantly, but the maximum daily rainfall showed a decreasing trend at p <0.10. Although Xiliugou did not implement soil and water conservation in the 1990s, due to the transfer of rural surplus labor, the pressure on the land was reduced and the damage to the vegetation was greatly weakened. As a result, the vegetation gradually recovered and the NDVI showed an upward trend. As a result, the erosion yield Weakening sand. The yield modulus of the “Ten Hole Holes” The natural geography of the basin has obvious changes. From west to east, the frequency of sandstorms decreases and the rainfall increases. Sand dune types also changed, mainly from mobile sand dunes to semi-fixed sand dunes, and decreased sediment transport into the sandstorms. On the other hand, hydraulically driven erosion and sediment transport increase from west to east. As a result of the superimposition of the above two effects, a peak area of erosion and sedimentation occurs near Xiliugou in the central part of the area.