Distribution of the Granulometric Composition of Floodplain Alluvium in the Middle and Upper Reaches of the Desna River and its Determining Factors

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.