Canyon, Ravine, Gorge, Gully
A canyon or gorge is a deep ravine between cliffs often carved from the landscape by a river. Rivers have a natural tendency to reach a baseline elevation, which is the same elevation as the body of water it will eventually drain into. This forms a canyon. Most canyons were formed by a process of long-time erosion from a plateau level.
A gully is a landform created by running water, eroding sharply into soil, typically on a hillside. Gullies resemble large ditches or small valleys, but are metres to tens of meters in depth and width. When the gully formation is in process, the water flow rate can be substantial, which causes the significant deep cutting action into soil.