What is a Gully?

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 metres in depth and width.

When the gully formation is in process, the water flow rate can be substantial, causing a significant deep cutting action into soil.

Hillsides are more prone to gullying when they are cleared of vegetation, through deforestation, over-grazing or other means.

What is a Rill?

A rill is a shallow channel (no more than a few tens of centimetres deep) cut into soil by the erosive action of flowing water. Similar but smaller incised channels are known as microrills; larger incised channels are known as gullies.

Artificial rills are channels constructed to carry a water supply from a distant water source. In landscape or garden design, constructed rills are an aesthetic water feature.