The Tagliamento has many tributaries, the main ones being Degano, But, Fella, Leale, Arzino, Cosa, Ledra e Varmo. Also thanks to its tributaries, it collects stones and gravels from all over the eastern Alps.
The gravels of the Tagliamento are much darker than the ones of the Fella. In the Fella basin carbonatic rocks predominate, including limestones and dolomites. These are mostly white, light gray or pink. The Tagliamento basin comprises mostly paleozoic rocks (sandstones), which are darker to reddish.
The richness and diversity in colors and shapes is also visible in the walls and pavements of the local buildings.