What does arroyo wadi and nullah?

An arroyo, wadi, and nullah are all terms used to describe dry riverbeds or stream channels that may flow intermittently. An arroyo refers specifically to a dry creek or stream bed in the southwestern United States, while a wadi is a term commonly used in the Middle East and North Africa for a valley or dry riverbed that can flood during heavy rains. Nullah is a term used in South Asia, particularly in India and Pakistan, to describe a seasonal river or stream. All three terms highlight geographic features shaped by water flow, primarily in arid or semi-arid regions.