This is the 9911th most frequent French word.
fluviale
"Fluviale" means "related to rivers."
Here, 'fluviale' modifies 'navigation', indicating that the navigation mentioned pertains to rivers.
La navigation fluviale est essentielle pour le commerce régional.
River navigation is essential for regional commerce.
In this case, 'fluviale' describes 'faune', specifying that the fauna being referenced is associated with rivers.
La faune fluviale est riche en espèces diverses.
The river fauna is rich in diverse species.
Here, 'fluvial' refers to 'système', highlighting the system's relation to rivers.