A RIVULET is a small river or brook, typically one that is shallow and flows quickly. It is usually smaller than a stream and often has a stony bed. Rivulets are often found in mountainous areas, where they form as a result of melting snow or ice. They can also be found in areas with high rainfall, where they form from runoff. Rivulets are important for providing water to plants and animals, and they can also be used for irrigation and other purposes.