Ephemeral gully erosion is a common type of water erosion in the loamy and silty loam soils developed over basin schists in the Ordenes Complex of A Coruna province (NW Spain).

The critical period for gully formation is any time when the soil surface remains bare and short intense rainfall events occurs.

Three case studies of severe gully erosion on small cachtments and hillslopes ( 0.84 to 5.72 ha size) are presented. The first occurred in later spring, the second was caused by a strong summer thunderstorm and the third was promoted by early winter rainfall.

The objective of this study was to describe different types of ephemeral gullies and to determine their origin. Gullies formed within the field where runoff starts, gullies collecting the runoff from an upstream area and discontinuity gullies due to abrupt slope changes were identified.

The main cause of gully formation is the lack of any proper waterway for conveying water excess.