Stream bed

Channel bottom of a stream, river, or creek

A streambed or stream bed is the bottom of a stream or river and is confined within a channel or the banks of the waterway. Usually, the bed does not contain terrestrial (land) vegetation and instead supports different types of aquatic vegetation (aquatic plant), depending on the type of streambed material and water velocity. Streambeds are what would be left once a stream is no longer in existence.

From Wikipedia, under CC BY-SA. More on occurri.