|arroyo (ə-roi'ō) Pronunciation Key
A small, deep gully or channel of an ephemeral stream. Arroyos usually have relatively flat floors and are flanked by steep sides consisting of unconsolidated sediments. They are usually dry except after heavy rainfall.
a dry channel lying in a semiarid or desert area and subject to flash flooding during seasonal or irregular rainstorms. Such transitory streams, rivers, or creeks are noted for their gullying effects and especially for their rapid rates of erosion, transportation, and deposition. There have been reports of up to 8 feet (2 m) of deposition in 60 years and like amounts of erosion during a single flood event
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