ИСТИНА

The empirical three-dimensional hydraulic gully erosion and thermo-erosion model GULTEM was developed for the first stage of gully evolution. At this stage the erosion and thermos-erosion is predominant at the gully bottom and rapid mass movement occurs on the gully sides. Gully channel formation is very intensive and morphological characteristics of the gully (length, depth, width, area, volume) are far from stable and changing rapidly. It is necessary to model the following main processes: a) Formation of a rectangular cut at the gully bottom by flowing water during snowmelt or a rainstorm event. b) Gully bank erosion and bottom width formation c) Transformation of a gully with new rectangular bottom cut into a gully of trapezoidal shape by shallow landslides during the period between adjacent water flow events.