常常与水路地形的原素(支谷,狭谷,长谷,洪水河道)的下游,发生水势集中而汹湧的急流,冲刷表层土、底层土(他于表层之下原始层之上)甚至原土层,并造成溪谷及很深的雏谷(例如在伏尔加河右岸深达百余公尺)。苏联的雏谷总面积虽未确定,但在欧洲部份约有450万公顷,不均匀地分布于各处。某些区域被雏谷分割的程度竟达到惊人的地步,例如在阿路劳夫州的克劳姆斯克地区雏谷约占总面积的30%。 Often, downstream and upstream from the elements of the waterway topography (canyons, valleys, valleys and flood waters), there is a concentrated and turbulent rapids stream that scours the topsoil, the subsoil (above the surface pristine layer) The soil layer, causing the valley and the deep Chuya (for example, up to 100 meters deep on the Volga River right bank). Although the total area of ​​the Cubs of the Soviet Union is undetermined, about 4.5 million hectares are scattered throughout Europe, unevenly distributed throughout the area. The extent to which some areas have been divided by the valley has reached alarming proportions, such as about 30% of the total area in the Hellevohoru region.