The article analyzes the conditions for the formation of the river channel and river morphology in the lower reaches of the Ob River within the Yamalo-Nenets Autonomous Okrug.Despite its important economic and water transport significance, the lower Ob River has remained practically unexplored until now.The geomorphological structure of the valley determines the formation of a wide-floodplain channel.The floodplain reaches 50 km across and narrows to 10 km only near Salekhard.For the first time, the bifurcated channel appears within the Khanty-Mansi Autonomous Okrug.The beginning of the bifurcated channel within the Yamalo-Nenets Autonomous Okrug is the Bolshoy Nyurik branch between the two main branches-Malaya Ob and Bolshaya Ob.Numerous floodplain channels branching off from the Malaya Ob reduce its water content to 10% of the total water.This is accompanied by a change in the river morphology and the parameters of riverbends.At the same time, the intensity of riverbank erosion decreases.In addition to the riverbends on the Malaya Ob, there are often segments of an unbranched channel.The Bolshaya Ob has an unbranched channel due to its location along the right valley side.Along with the data on water runoff dispersion, the data on the distribution of suspended load along the branches are presented during the flood.It is shown that its change is greatly influenced by riverbanks erosion and the floodplain branches, especially on the Malaya Ob.The obtained materials, in addition to general scientific value, are important for substantiating projects for water management and water transport development of the Ob River.

: In 2012-2015, the Makkaveev Research Laboratory of Soil Erosion and Fluvial Processes of MSU, Department of Geography, carried out a research, including analysis of hydrological and channel regimes of the Tom river in the Kuznetsk basin (Kuzbass) and the Katun river up to Uimonsky (the Altai), intra-mountain drainage basins, the survey of floodplains and eroded banks, and modelling of floods occurring in floodplains. As a result, a concept has been developed to improve protection measures against hazardous hydrological and channel processes. More than 200 engineering and organisational events were suggested as part of the concept. Given the dense network of river banks and the high potential damage caused by floods in Kuzbass, the continuous protection of cities, large residential and commercial areas, as well as sections of roads and railways subject to erosion is a priority in the flood control concept. In the case of the Katun river basin, characterized by local development, low population density, and relatively small damage caused by floods, the emphasis is put on organisational measures: prevention, evacuation of people and property, insurance and compensation. Selective engineering structures should, as a matter of priority, reduce the dangerous erosion of river banks and ensure a high level of protection of the territory against floods.

Communicational analysis of scientific laboratories, based on the scientometrical methodology, has been well developed since the second part of xx century. Still, it seems to be underestimated in the field of studying meta-organizational communities. The given article presents the results of exploring the structure and dynamics of the meta-organizational community by means of the communicational analysis. The selected object of the study is The Interuniversity scientific-coordination council on the problems of erosion, channel and river mouth processes at the Lomonosov Moscow State University. The Council exists for over 30 years and has established itself as a reputable scientific community. The empirical base of the study is the collections of scientific works, published during the annual conferences of this Community. The analysis has allowed to describe the particular activity of the Community - it showed the main stages of formation and development, which can be described by a cyclic model (3- and 8-year cycles were presumably detected). The structure of the Community has also been well described at its different levels - individual, organizational, inter-regional and international. The individual level reveals the "core" of the most active participants of the Community - only 3% of the communicators mostly determine sustainable reproduction of the publication activity. The analysis of individual co-authorship within the Community reveals following tendencies: 1) the number of individual scientific works is constantly decreasing, which may be a consequence of the prevailing collective nature of modern scientific research; 2) in the periods of social instability the number of individual applications increases, the Community itself reduces its activity. The analysis of the co-authorship within the "core" of the Community allows us to conclude, that the most important members might be the researchers, who have regularly published both individual and collective materials. Generally, they appear to be the leaders of some scientific schools, bringing their own concepts and then developing them in a team. The next (organizational) level reveals the involvement of different universities, institutes, laboratories, scientific schools and other organizations, as well as their contribution to the activity of the Community. The stable part of the Community consists of only 6% from the total number of the participating organizations. Generally, these organizations represent the most actively developing directions of research relevant to the Community. The regional and international levels show the width of the discussing scientific issues, as well as the efficiency of consolidation within the given scientific Community. During the years of its existence, the Community involved the participants from 23 countries, represented by 90 different cities. The leadership in the participation belongs to Russia, Ukraine and Poland. Thematic analysis has also been provided as one of the most productive methods of modern scientometrical research. The results allow us to determine the most sustainable fields of study and their dynamics. E.g., theoretical publications dominated over empirical ones in the period of << start-upD as well as in the periods of social instability - at the time, when some serious << breakthrough >> was needed to define a new course of development for the whole Community. Thematic analysis has also identified the main interdisciplinary connections and tight communications with larger scientific sub-disciplines (geography, physics, chemistry, social sciences, etc.). As one of the most important results, it has been defined that the activity of the Community is inherently linked to one of the most important issues of our time: ecological problems of anthropogenic transformation of the environment.

: The Ob River is one of the largest rivers in Russia and currently the most important traffic route in Western Siberia. The paper presents the history of water transport on the Ob River against the background of channel processes limiting the navigation on the river. The heterogeneity of the Ob River is determined by specific features of the channel processes and the stability of the riverbed, morphological types of the channel, the nature of deformations, long-term and seasonal changes of riffles and sections of the channel characterized by the presence of riffles. The main measures aimed at improving the navigational conditions of the Ob River include dredging of riffles, construction of dams and bypass channels.

Reconfiguratings of the Lena river bed near Yakutsk city (one of the most complex part of the river concerning channel deformations) have directional character, and it caused gradual river drift away from the city. Development of the right-hand tributaries system mostly occurred near Yakutsk, meanwhile the left-handed ones (where the city is situated) grow shallow, and it leads to troubles in operation of municipal water intakes, water accesses to the city, complication of navigability etc. Nowadays the Lena river development is defined by: 1) transforming of the adjacent tributaries into parallel-channeled ones near Yakutsk, upfront not-forks in upper reaches and alternate one-sided forks in the lower reaches; 2) multidirectional river channel shift near Yakutsk – towards right with the right branch development, and towards left with development of shallow bend – on the adjacent section in upper reaches; 3) transgressive shift of the fl ood-plain island massives – its washaway from the heads and extension of the downstream ends, which lead to the shallowing of left branch (Adamovsky channel) near Yakutsk and development of the right-hand channel here. General regularities of the river bed reconfiguratings allowed to elaborate the trial scheme of recommendations to castigation of the present negative situation on the Lena river near Yakutsk city based on the river processes management and formation of conditions for its development in right direction, as well as to validate the program of detailed researches for the mathematic modelling of the river bed reconfigurations and engineering of hydrotechnical measures.

Reconfiguratings of the Lena river bed near Yakutsk city (one of the most complex part of the river concerning channel deformations) have directional character, and it caused gradual river drift away from the city. Development of the right-hand tributaries system mostly occurred near Yakutsk, meanwhile the left-handed ones (where the city is situated) grow shallow, and it leads to troubles in operation of municipal water intakes, water accesses to the city, complication of navigability etc. Nowadays the Lena river development is defined by: 1) transforming of the adjacent tributaries into parallel-channeled ones near Yakutsk, upfront not-forks in upper reaches and alternate one-sided forks in the lower reaches; 2) multidirectional river channel shift near Yakutsk – towards right with the right branch development, and towards left with development of shallow bend – on the adjacent section in upper reaches; 3) transgressive shift of the fl ood-plain island massives – its washaway from the heads and extension of the downstream ends, which lead to the shallowing of left branch (Adamovsky channel) near Yakutsk and development of the right-hand channel here. General regularities of the river bed reconfiguratings allowed to elaborate the trial scheme of recommendations to castigation of the present negative situation on the Lena river near Yakutsk city based on the river processes management and formation of conditions for its development in right direction, as well as to validate the program of detailed researches for the mathematic modelling of the river bed reconfigurations and engineering of hydrotechnical measures.

Along the entire length of a large river there is taking place a substantial change in the formation conditions and stability of the channel, the rate and character of channel deformations and, accordingly, in the possibilities of water resources utilization, transport and engineering development of the river. By parametrizing the channel processes, it is possible to rank the river sections according to the degree of complexity of the channel processes, forms of their manifestation, and to the regime of channel reconfiguration, which, in turn, determines the possibilities of planning the measures ensuring the water resources utilization. Using the Ob’ as an example, we provide a rationale for the criteria for singling out the river sections differing by the degree of complexity of the channel processes, on the basis of parameters characterizing the forms of their manifestation, the state of the channels, and the intensity of deformations. We have identified eight sections of a different length, sequentially alternating along the length of the river from the confluence of the Biya and Katun’ as far as the mouth. The ranking of the river sections permitted the future planning of the water resources utilization measures.

Using the confluence nodes of broad-floodplain rivers as an example, we examine the different variants of effects of channel deformations (channel meandering of the main river and its tributary, formation of forks, and shift of meander bars) upon their configuration and reconfiguration across time. We demonstrate the diversity of these effects even where the deformations themselves are of the same type. Problems of further investigations are formulated.

We examine the transformation of a gentle segmental to a meander loop with the result that the city, founded in the 17 th century, found itself on the caving bank. Comparison of cartographic materials from different times showed the occurrence of secondary bends on elongated rectilinear wings. Not only did such an evolution of the meanders lead to the caving of the terraced urban bank, but also it involved a likely emergency situation on the underwater crossing of the pipeline, and on other engineering facilities. We ascertained the causes of the ongoing channel deformations; modeling data were used in developing recommendations on meander straightening in order to divert the river away from the city.

Features of present-day channel deformations of the Tom' River within the Tomsk region and related processes of the ice jams’ formation have been considered. Recommendations about prevention of their negative consequences have been offered. They include organizational, scientific/information and engineering measures of the damages prevention against dangerous hydrological processes under consideration.

Дан анализ условий и механизма формирования параллельно-рукавных разветвлений – наименее изученной и наиболее сложной разновидности многорукавных русел. Обоснована их связь с возникновением вертикальной границы раздела водных масс в реках со слабоустойчивым широким распластанным руслом, большим стоком руслообразующих (влекомых) наносов. Детально описаны русла этого типа на Северной Двине и верхней Оби.

The conditions and mechanisms of the formation of parallel-branch braidings—the least studied and most complex variety of braided channels are analyzed. They are proved to be related with the appearance of a vertical interface between water masses in rivers with weakly stable, wide, spread channel; large runoff of channel-forming (tractable) sediments. Channels of this type in the Northern Dvina and the Upper Ob are described in detail.