黄土丘陵区近10年来典型小流域对侵蚀环境演变的泥沙响应

针对近年来黄河泥沙的锐减现状,以2003—2011年国家退耕还林工程实施效果的显现期为背景,采用典型流域剖析的方法,深入研究了近10a来黄土丘陵区典型流域侵蚀泥沙总量以及年际变化量。结果表明:小流域土壤侵蚀强度大幅度下降,年平均侵蚀模数不足500t/(km~2·a),下降至退耕还林还草工程实施以前的8.3%;如不考虑建坝初期2003年的特殊状况,小流域2004—2011年侵蚀模数平均值为144.93t/(km~2·a),为退耕前的2.4%。这表明在新的侵蚀环境背景下该小流域的侵蚀强度已稳定在轻度以下。

Sediment Response to Erosive Environment Evolution of a Typical Watershed in the Loess Hilly Region in the Past 10 Years

Sediment discharge significantly decreased in the Yellow River because of the effect of the ‘grainfor-green project’ (GGP).The typical watershed parsing method was applied to obtain the sediment yield and analyze the variation of the annual erosion modulus in a typical watershed in the loess hilly-gully region between 2003 and 2011.The results indicated that sediment yield from the watershed declined dramatically,and the average erosion modulus was less than 500 t/(km2 · a),which was 8.3％ of that before the implementation of GGP.Moreover,when excluding the data in 2003 because of the influence of the beginning of dam implement,the average erosion modulus during 2004-2011 was 144.93 t/(km2 · a),which was only 2.4％ of that before the implementation of GGP,suggesting that there was a mild erosion in this watershed after the GGP.This study proved the significance of the effects of controlling sediment yield of the GGP,and it may help the planners and managers to make proper decisions for the control of soil erosion from watersheds under similar conditions.