黄河中游多沙粗沙区淤地坝拦减粗泥沙分析

本文对地处黄河中游多沙粗沙区的河口镇至龙门区间（简称河龙区间）及四大典型支流皇甫川、窟野河、无定河和三川河流域淤地坝拦减粗泥沙效果进行了深入分析，计算了不同年代淤地坝拦减粗泥沙量。通过分析实施淤地坝等水土保持措施前后泥沙粒径的变化、淤地坝配置比例与减沙比例关系的变化后认为：淤地坝是快速减少入黄粗泥沙的首选工程措施和第一道防线，具有明显的“拦粗排细”功能。只要河龙区间坝地的配置比例保持在2%左右，其减沙比例即可达到45%以上。当四大典型支流淤地坝配置比例平均达到2.5%时，淤地坝减沙比例平均可以达到60%。因此，为有效、快速地减少入黄泥沙尤其是粗泥沙，河龙区间水土保持措施应采用以淤地坝为主的工程措施与坡面措施相结合的综合配置模式。淤地坝的配置比例应保持在2%以上。减少黄河粗泥沙的重点支流应首选窟野河和皇甫川。

Effect of check dam on retaining and reducing coarse grain sediment in middle reaches of Yellow River

The effect of check dam on retaining and reducing the coarse grain sediment in the middle reaches of Yellow River from Hekouzhen to Longmen and its four typical tributaries are investigated. The amounts of retained and reduced coarse grain sediment in different years are calculated. According to the changes of sediment grain size and the relationship between the allocation ratio of check dam and sediment reduction ratio, the effect of check dam on retaining coarse sediment and flushing fine sediment is analyzed. When the allocation ratio of check dam in the middle reaches of Yellow River is 2%, the sediment reduction ratio reaches 45%; similarly, when the average allocation ratio in four tributaries is 2.5%, the sediment reduction ratio reaches 60%. It may conclude that the adoption of check dam combining with slope surface protection measure is a suitable approach to reduce the sediment, especially the coarse sediment, flowing into the Yellow River.