The harbour has now silted up.

港口现已淤塞。

《牛津词典》

Sand has silted up the river delta.

泥沙把这条河的三角洲淤塞了。

《牛津词典》

The waterway is silted up.

航道淤塞。

《新英汉大辞典》

Others have been badly maintained or have simply silted up.

ECONOMIST: Small projects often give better returns

Sanmenxia was the nation's pride until its reservoir silted up.

ECONOMIST: China and opposition to dams

The site has been under excavation since the late nineteenth century, so that all of its surviving monuments have been unearthed and to some extent restored, though its ancient harbor, the Lion Port, has long been silted up, leaving Miletus marooned miles from the sea.

WSJ: 'Aladdin's Lamp'