Which type of stream flows continuously throughout the entire calendar year?

A perennial stream is characterized by its continuous flow throughout the entire calendar year. This consistent flow is primarily due to a reliable source of water, such as a spring or consistent precipitation that replenishes the stream even during dry periods. Perennial streams are essential for maintaining ecosystems, supplying water for wildlife, and providing resources for human use and agricultural purposes.

Intermittent streams, on the other hand, flow only during certain times of the year, usually in response to seasonal rains or snowmelt, and can dry up during dry seasons. Ephemeral streams flow only during and immediately following precipitation events and are typically active only for a short period. Seasonal streams might flow at specific times of the year, generally tied to climatic patterns.

Thus, the defining feature of a perennial stream is its ability to maintain a consistent flow throughout the year, distinguishing it from the other types of streams that experience fluctuations in their flow due to environmental conditions.