黄土高塬沟壑区产沙驱动力及减沙潜力分析

摘要

The sediment reduction trend in the core gully plateau region of Loess Plateau which located in the Jinghe River is still inconspicuous, while the sediment yield of most tributaries in the upper and middle reaches of the Yellow River reduced significantly since 1970s. This phenome-non is related to the special sediment production mechanism of the gullied rolling loess area. This study shows that:the runoff intensively run along tableland to valley is the major driving force for sediment production,especially the runoff running along the courtyard and road in the tableland to valley;the potential sediment reduction of terraces,tree and grass vegetation are hardly over 10% in the regions that tableland area accounted for more than 60% of the whole plateau region;reducing the runoff running along tableland to valley as much as possible is the key factor to control e-rosion and sediment yield.%20世纪70年代以来，黄河上中游绝大部分支流来沙明显减少，但泾河流域黄土高塬沟壑区的核心地区无明显减沙趋势。以地处董志塬核心区的南小河沟和砚瓦川流域为例，分析了水土流失治理前后的降雨-产沙关系，以及塬面、坡面和沟谷的产水产沙量，结果表明：塬面径流集中下沟是流域产沙的主要驱动力，尤以庄院和道路径流集中下沟为甚；在塬面面积占流域面积60％以上的完整高塬区，梯田和林草措施的减沙潜力很难超过10％；尽可能减少集中下沟的塬面径流量是遏制该区侵蚀产沙的关键。