ИСТИНА

Fluvial processes at the areas with humid conditions are among exogenic phenomena that are most active constantly and most reactive due to the ongoing climate changes. It is especially important to study their reactions in the areas with high anthropogenic load or intensive development of landuse. Our work is conducted at the Sochi region, the Black Sea coast of Russia. This area is known for its mountainous topography, wet subtropical climatic conditions and intensive anthropogenic development. The most river valleys are short, V-shaped and oriented towards the sea. Systematic storms cause floods and flash floods that are regularly reported along the whole coast, increase the total sediment flux and activate the other processes at the area. Since 2013 we monitored a few key study sites at the Tsanyk river in Khosta district of Sochi to get the data of the valley development under the described conditions. A set of methods was used. 3D-scanning, metal pins and stereophotography are aimed to quantify the rates of channel erosion and landslide processes at its banks. Lithological study of the channel and weathering rates monitoring let to describe the sediments, track their sources and ways to the stream. The rates of erosion highly depend on the channel morphology and vary a lot along the river. The results of sediments production monitoring will be presented for all typical cross-sections of the valley bottom.