A dry gully is often referred to as a arroyo or a wash.
gully
arroyo
Arroyo
arroyo
a wash
Arroyo ; " A deep gully cut by an intermittent stream; a dry gulch. "
Arroyo, gully, wash or wadi depending on the area of the world and local language customs.
A wash is an arroyo, or gully or wadi that is normally dry but quickly fills with water after a heavy rain.
gully erotion is something that makes trenches
The plural of gully is gullies. As in "this is the gullies".
Depending upon the area of the world it may be called an arroyo, a wash, a gully, a gulch or a wadi.