The paper provides an assessment of the activities carried out by the Interuniversity Scientific Council on erosion, channel and estuarine processes research at the Lomonosov Moscow State University over the past 5 years (2021–2025) and being a logical continuation of the Council activities over the 40 years of its existence. Problems associated with the work of the Council and purposes for the nearest future are reviewed.
The floodplains of branched rivers are diverse, but the fundamental mechanism of their formation is similar. The formation of branches is associated with the division of the river stream into several flows and the formation of mid-channel sediment bars in the accumulation zones between the dynamic axes of the flow, which, when drying out in low water, are fixed by vegetation and turn into elementary floodplain islands. The channels between the elementary islands become shallow and drift over time; a consolidated island massif appears, which, when one of the river branches dies off, joins the shore. The former islands become wide elevations with a relatively flat surface, and the channels become hollows of various sizes. The morphological appearance of floodplains of rivers with branched channels is diverse, since the relief and linear dimensions of its elements, the number and characteristics of former channels and branches between islands, and the landscape structure depend on the structure and morphology of the branches, their transformations, the water runoff and hydrological regime of the river, and anthropogenic influences. The article examines the morphology, formation and evolution of floodplains in the valleys of branched rivers, and characterizes their main types.
Relevance. The transboundary basin of the Ural River has been experiencing a rather tense water and ecological situation for the last decades. The existing contradictions in understanding of the ongoing hydrological and ecological changes in the Ural River itself, as well as its numerous tributaries, necessitate a comprehensive study of the influencing natural and anthropogenic factors, identification of their significance on an interstate scale and application of the obtained materials in the system of management of water use and water protection measures in the river basin as a whole. Proceeding from the above, the article presents the results of the study of small rivers of the Ural River basin within the Russian Federation, characterised by the peculiarities of changes in river flow and environmental conditions in them depending on the influence of a combination of natural and anthropogenic factors. Published and stock sources, as well as materials obtained as a result of numerous scientific researches and investigations in the river basin under the scientific supervision of the author were used as initial information.
As a result of the study, the peculiarities of the impact of human economic activity on small rivers and natural complexes of their catchments have been revealed. The characteristics of spatial and temporal variability of influencing factors on the change of slope and river flow are revealed, the features of influence of anthropogenic factors on water quality in water bodies and ecological conditions in them are studied, proposals on ecological rehabilitation, conservation and restoration of small rivers - tributaries of different orders of the transboundary Ural River are substantiated.
The results of a study of channel displacement for 2000–2022 in 55 key areas located on rivers of different orders, flowing in different landscapes of Udmurtia, are presented. The erosion rates were determined using benchmarks and tacheometric survey. To analyze the obtained results, the rivers were divided into 4 groups according to the magnitude of their orders (according to the method of A. Scheidegger). Maximum erosion is typical for rivers with an order higher than 14 (up to 15 m/year), for medium rivers with an order of 9–14 these values are 6–8 m/year. For small rivers with an order of 6–9, the maximum erosion reached 5.5 m/year, and for very small rivers (of order 6 or less), respectively, up to 4.2 m/ year under natural conditions and up to 8.1 m/year at man-made intervention. Statistical indicators of the average annual and maximum erosion in the reference areas for the period under consideration were obtained. Correlation analysis showed a high significant relationship between the erosion rate and the order of the river and, accordingly, the average annual and maximum discharges. An analysis of erosion over a 23-year time interval is given with the definition of the trend equation for the selected groups of rivers.
Changes of small rivers channels occur in conditions of low water runoff, significant dependence of morphology and morphometry on local factors, sensitivity to anthropogenic impacts. This causes low intensity of bank erosion and the emergence of diversity of its relationships with factors of channel processes, which complicates the analysis of channel deformations. Field monitoring helps to solve this problem. The article examines the methods, analysis techniques and some results of monitoring of bank erosion at 15 sites of small rivers channels in the Kudma basin for the period from 2010 to 2023. The measurement data show a significant spread in the values of indicators of erosion rates: length of eroded bank varies from 10 to 80 m/year, eroded area – from 2 to 15 m2/year, average rate of bank retreat is from 0.1 to 0.3 m/year, maximum – 0.4 to 1.0 m/year. Identification of relationships with factors of channel processes (water runoff, geological and geomorphological conditions, morphodynamic type of channel, local conditions) made it possible to divide the studied channels into groups with qualitative differences in the manifestation of morphodynamics. On straight channel the development of bank erosion is largely determined by local conditions. The dependencies of erosion indicators are most clearly manifested on wide-floodplain meanders. The area of erosion has the closest relationship with the forming conditions.
The paper presents the results of geomorphological stationary works in the downstream of the Oka River bend near the “Kostino” village, center of the European part of Russia. Field observations of bank erosion rates at this survey site indicate an annual retreat of 1.67 m of the subaerial part of the bank. During two years of monitoring, spring floods completely flooded the stationary. In 2023, the maximum discharge of the Oka River was approximately 4700 m3/s and exceeded 2022’s value by 62%. We used unmanned aerial vehicles (UAVs) and obtained high-resolution surface rasters and calculated linear, area and three-dimensional erosion rates. The relief response to increased flood energy in the second year of observations was expressed in almost twofold acceleration of bank failure (by 95%). The concave bank sections, composed of sand and sandy loam, have undergone particularly intensive erosion in a number of places, which is confirmed by our monitoring of the channel bed. By surveying by season of the hydrological year, we found that subaerial bank erosion does not stop in summer and autumn, although it only reaches 20% of the full-year volume.
The article provides information on the granulometric composition of the grounds of the central floodplain in the upper and middle course of the Desna River with a length of 256 km. The factors determining the overall picture of the fraction ratio (based on materials from more than 100 samples) are considered. The information on the differences in the granulometric composition of floodplain sediments in the middle reaches of the Desna River is systematized. Differences in the composition of floodplain sediments are compared at the level of 18 stream segments, isolated by geological and geomorphological features of the valley structure. It is shown that the differences in the fraction ratio are formed under the influence of both general patterns of changes in the composition of sediments downstream and local features of the sources of material intake due to differences in the structure of the valley and the drainage basin.
The article discusses the methodology of compiling highly specialized thematic geographical atlases. The need for this arose when trying to present in print a huge field material of the expeditionary work of the N.I. Makkaveev Scientific Research Laboratory of Soil Erosion and River Channel Processes of the Lomonosov Moscow State University Faculty of Geography and the Laboratory of Bottom Sonar of the P.P. Shirshov Institute of Oceanology of the Russian Academy of Sciences, conducted jointly in estuaries and river deltas on the coasts of marginal and inland seas of Russia during the period 1969–2015. In total, five atlases were compiled, and four were published. When creating the atlases, developments in the content, structure, design of the atlas, and the construction of a legend of geomorphological maps were used, taking into account the available array of field data, modern technical and software capabilities. In each atlas, cartographic and special illustrative content was represented by geomorphological maps, satellite images, diagrams of horizontal channel deformations, echo-sounder profiles and sonar images for selected areas. Each section represented a separate subsection, called a "sheet", which had its own serial number and was reflected in the table of contents. Geomorphological cartographs were compiled on the basis of large-scale topographic maps using satellite images that are publicly available. The genesis of the relief has traditionally been shown by a qualitative background, and the age by geological indexes. All monograph atlases published and prepared for publication are special thematic scientific reference works, which summarize in a colorful and accessible form the vast natural material on geology, geomorphology, hydrology and geophysics of estuaries and deltas of large rivers flowing into the marginal and inland seas of Russia.
