Riva vs. sponda vs. argine

The Italian words 'riva', 'sponda', and 'argine' all refer to the bank or edge of a river, but they have subtle differences in usage and context.

Riva

'Riva' typically refers to the shoreline or bank of a body of water, including rivers, lakes, and seas. It often implies a natural, gently sloping edge where people can easily access the water.
I bambini giocavano sulla riva del lago.
(The children were playing on the shore of the lake.)
Abbiamo fatto una passeggiata lungo la riva del fiume.
(We took a walk along the riverbank.)

Sponda

'Sponda' is a more general term for the bank or edge of a river or stream. It can refer to both natural and artificial banks, and is often used when describing both sides of a waterway.
Il ponte collega le due sponde del fiume.
(The bridge connects the two banks of the river.)
Le sponde del ruscello erano coperte di fiori selvatici.
(The banks of the stream were covered with wildflowers.)

Argine

'Argine' specifically refers to an artificial embankment or levee built along a river or canal to prevent flooding. It's a man-made structure designed for flood control.
L'argine ha protetto la città dall'inondazione.
(The levee protected the city from flooding.)
Stanno rafforzando gli argini del canale per prevenire future alluvioni.
(They are reinforcing the embankments of the canal to prevent future floods.)

Summary

While 'riva' typically refers to a natural shoreline of any body of water, 'sponda' is a more general term for river banks, and 'argine' specifically denotes an artificial embankment for flood control. 'Riva' is often associated with accessible, gentle slopes, 'sponda' can describe both sides of a waterway, and 'argine' always implies a man-made structure.