google
yahoo
bing
arroyo a deep gully cut by an intermittent stream
gulch a small ravine, usually cut by a torrent

Examples  

Early settlers of the west learned to avoid arroyos because of flash flooding.
The southwest is dotted with dry gulches and stream beds.1
Notes1
arroyo is Spanish; gulch is English for the smaller products of water erosion. See canyon/ravine/gorge