求翻译：上世纪80年代以来，黄河上游宁蒙河段粗泥沙淤积日益严重，粗泥沙来源问题目前已成为制约该河段治理与开发的重点与难点。是什么意思？

Since the 1980s, Ningxia and Inner Mongolia reaches of the Yellow River upstream coarse sediment deposition is an increasingly serious source of coarse sediment has become important and difficult to restrict the reach of governance and development.

Since the 1980s, Huang He river upstream, rough, sedimentation, and increasingly serious thick mud and sand from now on the river of the governance and development with the focus on pain.

Since on the century 80's, upstream Yellow River rather has hoodwinked the section of river thick silt siltation to be day by day serious, the thick silt origin question has become at present restricts this section of river government and the development key point and the difficulty.

Since the 80 's of last century, coarse sediment upstream of Ningxia-Inner Mongolia section of the Yellow River is becoming increasingly serious, coarse sediment source problems has now become the emphases and difficulties of restricting the reach of governance and development.

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