What is a defining feature of a perennial stream?

A defining feature of a perennial stream is that it contains water year-round during normal rainfall conditions. This means that regardless of seasonal changes, a perennial stream consistently flows, unlike streams that may dry up during particular times of the year. The continuous presence of water allows for a stable ecosystem that supports various plant and animal life, making it an essential habitat. Other types of streams, such as intermittent or ephemeral streams, may flow only during certain seasons or after rain events but do not provide the same year-round water supply. This characteristic of being reliably flowing year-round is fundamental to identifying a stream as perennial.