恒こう常じょう河か川せん

noun

perennial river; permanent stream

Technical term in geography and hydrology for a river or stream that flows year-round. Rare in everyday conversation; more common in academic or environmental contexts.

• この地ち域いきの恒こう常じょう河か川せんは、年ねん間かんを通つうじて安あん定ていした水すい量りょうを保たもっている。

  The perennial rivers in this region maintain a stable flow throughout the year.