As an adjective fluvial
is of, pertaining to, inhabiting, or produced by the action of a river or stream.
As a noun antidune is
a bedform found in fluvial environments, opposing the direction of flow.
fluvial
English
Adjective
(
wikipedia fluvial)
(
-)
Of, pertaining to, inhabiting, or produced by the action of a river or stream
Synonyms
* (of a river): fluviatile, riverine
antidune
English
Noun
(
en noun)
A bedform found in fluvial environments, opposing the direction of flow.