A quantitative assessment of channel planform changes on the 600-km channel of the Kamchatka River was carried out. Possibilities of semi-automatic GIS-interpretation of satellite images were used for retrospective analysis of such an extended section of a large river. It was estimated that 37% of the left bank length and 44% of the right bank length are eroded. The amount of material coming into the channel due to riverbanks erosion significantly exceeds the sediment runoff, which determines channel type and regime of channel changes. Processes of bank erosion vary on the scale of the longitudinal profile and different channel types. Downstream according to decrease of channel slope, a decrease of bank erosion intensity is observed. The most important factor of bank erosion on the river local section is the volume of material coming from the upstream sections. A quantitative analysis and forecast of planform changes of a river section requires a differential assessment for different morphodynamic channel types, taking into account characteristics of channel processes in the upstream river sections. The bank erosion prognostic equations obtained for the meandering channel and the floodplain-channel multiple branches of the Kamchatka River are discussed.

This paper represents definitions of extreme and specific manifestations of channel processes and reviews relationships between themselves and connections with extreme or extraordinary hydrological situations. The main sign for referring channel processes as extreme is the anomaly of their manifestation, which is reflected in extremely high rates and duration of development (significantly exceeding the mean maximum values), unexpectedness of occurrence and difficulties or impossibility of forecasting. Specific channel processes occur in conditions of channel formation, which differ from typical for a river or rivers in the region and have limited distribution. Criteria provided to characterize the extremality or specificity of the manifestations of channel processes, their qualitative and quantitative assessments, as well as the analysis of hydrological, geological, geomorphological and anthropogenic factors of their origin and development are given. The spatial scale of manifestations, their frequency, negative social and economic consequences and the possibility of prevention are considered. An approach to the classification of extreme and specific channel processes and the evaluation of their risk to economic activity is proposed. Typical examples of extreme and specific manifestations of channel processes in various temporal and spatial scales and natural zones are shown.

Inundatios on the Black Sea coast of Krasnodar krai between 1945 and 2013 have been analyzed. The main genetic types of inundations on the coast have been identified. The specific features and regularities of inundation wave transformation along the rivers and over time have been studied. Seasonal and maximal runoff of Black Sea rivers has been analyzed over a long-term period. Regularities in the variations of the number of inundatios and their characteristics over the coastal area have been revealed both at the annual and long-term scales. Quantitative estimates are given to the hazard and damage to the population and economic activity due to inundations in the valleys of Black Sea rivers.

An assessment is made of the contribution from different sources supplying sediments to the rivers flowing in areas of open-cast mining of placers in places of their contemporary exploitation (using the Russian Federation and Mongolia as an example). We examine the sediment yield transformation processes in conditions of open-cast gold and platinum mining in the valleys of creeks and small and medium-sized rivers where extraction of mineral resources is an exceptionally important kind of activity (the rivers of the Vyvenka basin, Kamchatka krai) or characteristic for a given territory (Tuul river downstream of the city of Ulaanbaatar, Selenge river basin, Mongolia). We summarized the assessments of the sediment yield transformation downstream of the areas of mining placer deposits along the rivers of Russia, Mongolia, USA, India, Australia, and Surinam. It is shown that stream-channel erosion in anthropogenically modified channels is responsible for up to 90% of technogenic changes in sediment yield. The most significant (by several orders of magnitude) increase in sediment yield has been recorded for small rivers. For large rivers that are characterized by low background values of sediment yield, its change is by a factor of 1.1‒1.2 in the case of single mining operations in the drainage area and reaches a factor of five for large-scale mining operations.

Inundatios on the Black Sea coast of Krasnodar krai between 1945 and 2013 have been analyzed. The main genetic types of inundations on the coast have been identified. The specific features and regularities of inundation wave transformation along the rivers and over time have been studied. Seasonal and maximal runoff of Black Sea rivers has been analyzed over a long term period. Regularities in the variations of the number of inundatios and their characteristics over the coastal area have been revealed both at the annual and long term scales. Quantitative estimates are given to the hazard and damage to the population and economic activity due to inundations in the valleys of Black Sea rivers.