What characterizes a perennial stream?

A perennial stream is characterized by flowing continuously throughout the year, except during periods of drought. This consistent flow is maintained due to sustained sources of water, such as groundwater or frequent precipitation in the surrounding area.

In contrast, other characteristics described by the incorrect options demonstrate different types of streams. For instance, a stream that flows occasionally during heavy rain is classified as an intermittent stream, which only flows during certain seasons or weather events. The option regarding seasonal fluctuations in water flow also describes intermittent or seasonal streams, rather than a perennial stream. The last option about streams being restricted to urban areas is not a characteristic that applies to perennial streams, as perennial streams can exist in various natural and rural settings, not just urban environments. Hence, the defining feature of a perennial stream is its continuous flow, which aligns perfectly with the choice that states it flows continuously except in drought conditions.