The current of the river is fast flowing and treacherous.

河水的水流湍急而且变化莫测。

《柯林斯英汉双解大词典》

The terrain is mostly mountainous, with fast flowing rivers and few forests.

地形上几乎大部分是山地，河流湍急，植被稀少。

youdao

The tractor was resting against the crash barrier in the central reservation, having miraculously crossed the busy road with fast-flowing traffic.

拖拉机停靠在路中间预留地的防撞栏上，奇迹般地穿过了车流湍急的繁忙道路。

youdao

In many areas of fast-flowing water, a boat could be turned over by a wave as high as a house.

VOA: special.2009.10.07

Oulanka has fast flowing Arctic rivers that wash through vast stands of pine and threatened plants.

BBC: Europe��s wild network of Pan Parks

Our performance matched the sunshine with some wide, open, fast flowing rugby - much to my disgust!

BBC: Alan Paver column

Elsewhere, a canoeist had to be freed by firefighters after he was trapped in a fast flowing beck in Reeth, the fire service said.

BBC: Motorist rescued from floodwater in Hawes