Sarn Gebir

Sarn Gebir were the Rapids of the Great River Anduin. They appeared as the river's course passed between the Emyn Muil, above the Falls of Rauros. As they were unnavigable rocks and stony eyots, a portage-way was built on the western bank of the river, facilitating travel with light boats from Wilderland to Osgiliath, until the Orcs of Mordor began to multiply.

While the Fellowship of the Ring navigated the Anduin, Aragorn was preparing for the Rapids, but they reached them sooner than he reckoned, on midnight of 23 February. The stream pulled them towards the eastern bank, where they were ambushed by Orc archers from Mordor. The Fellowship paddled away from the rapids. During the next day they portaged a few miles to the foot of the rapids and resumed their paddling on the morning of 25 February.

Etymology

Sarn Gebir is a Sindarin name meaning "stone-spiked".

Other versions of the legendarium

In early manuscripts, Sarn Gebir was a name for the highlands which would later be named Emyn Muil.

Portrayal in adaptations

2001: The Lord of the Rings: The Fellowship of the Ring:

The ambush at the rapids of Sarn Gebir scene was actually intended to be in this film, to the point that an entire on-location set was built, but was not included in the final cut for one simple reason: before filming could begin on the set, record-breaking torrential rains and 20 foot high floodwaters washed away the entire set. So complete was the destruction that not even any wreckage of the set was ever found. Without the time or funding to construct a new set, the scene had to be cut from the script.