中文摘要：

位山灌区是黄河中下游引水能力最大的引黄灌区。1970年复灌以来，引水灌溉及跨流域调水引入了大量泥沙，使得灌区渠首地区泥沙淤积严重，清淤泥沙堆积成害。本文首先描述了位山灌区渠首地区泥沙淤积构成的耕地减少、土壤沙化、空气质量下降等灾害，从历年引水引沙变化、泥沙淤积分布、风沙起动机理等方面阐明了泥沙灾害的形成条件，进而对渠首地区泥沙灾害的根本成因——泥沙淤积进行了分析，为灌区采取合理的解决对策提供了依据。

英文摘要：

As the largest irrigation system along the Lower Yellow River, Weishan irrigation district suffers serious sedimentation problem. Weishan irrigation district has diverted large quantity of sediment since 1970. In this paper, the phenomena of the farmland loss, soil desertification and local environment deterioration caused by sediment piled up are depicted. The forming conditions of sediment disaster such as the increasing diversion volume, uneven siltation distribution and the mechanism of wind-blowing sediment are illustrated. Finally, the reasons of sediment siltation are analyzed.