黄河流域多沙粗沙区植被覆盖变化与减水减沙效益分析

通过遥感手段和数字流域模型,研究了黄河流域多沙粗沙区近10来年的植被覆盖变化及其减水减沙效益。研究表明,多沙粗沙区90年代末期与80年代末期相比,植被覆盖度增加区域大约占50%,植被覆盖度没变化区域约占48%。植被覆盖度的变化导致了流域水沙条件的变化,90年代末期植被覆盖条件下,植被措施的减水减沙百分比不高;不同的降雨过程,植被措施的减水减沙效益有一定的差别;从不同降雨过程多年平均看,近10来年植被措施年均减水2.63亿m3,减沙1.13亿t,减水减沙比为2.75,即减1亿t沙的同时减水2.75亿m3,减水百分比为7.61,减沙百分比为10.56,减沙效益大于减水效益。

Analyses on the variation of vegetation coverage and water/sediment reduction in the rich and coarse sediment area of the Yellow River basin

By means of remote sensing and digital basin model,this paper mainly studies the variation of the vegetation coverage and water/sediment reduction in the rich and coarse sediment area of the Yellow River basin.The results indicate that the areas in which the vegetation coverages in the rich and coarse sediment area have been increased and remained unchange are 50% and 48% respectively by the later 1990's compaired with that in the later 1980's. The variety of vegetation coverage influences the water and sediment condition of the river basin.According to the multi-year average value,from the end of 1980's to the end of 1990's,the planting measure in the rich and coarse sediment area has annually reduced water and sediment by 263 million cubic meters and 113 million tons respectively.The reduced percentages of water and sediment are 7.61% and 9.78% of the values in the late 1980's respectively.This indicates that the effect of sediment reduction is larger than that of water reduction.