GEOLOGICAL AND GEOGRAPHICAL FACTORS AND REGULARITIES OF THE VARIABILITY OF THE OKA RIVER WIDTH (BY THE EXAMPLE OF THE RYAZAN EXTENSION OF ITS FLOODPLAIN)

Abstract

Аim. The paper identifies geological, geomorphological and hydromorphological factors affecting the variability of the width of the Oka within the Ryazan extension of its floodplain. Methodology. The width of the Oka is determined using remote and field methods. At the cameral stage, we approximated established empirical values in STATISTICA 10.0 and MS Excel programs. Results. The location of the widest and narrowest sections of the Oka river is found for the Ryazan expansion of the Oka floodplain in its middle course. An average width (Bp) of each individual kilometer of the river is determined within a section of 743-662 km from the mouth, taking into account the local variability of the river morphodynamics. It is found that a significant factor, affecting the variability of Bp is the change in the morphodynamic type of the riverbed from anabranching to meandering. It is reveled that the approximation using the least weighted squares method turns out to be the most sensitive to the changes in river morphology. Reseach implications. Geological, geomorphological and hydromorphological factors affecting the Bp variability are analyzed. Statistical approximations of the obtained values of the morphological parameter are proposed. The minima of the riverbed width are found to correspond to floodplain areas that are atypical in geological and geomorphological terms, which should be taken into account in future forecasts of the development of riverbed deformations in the floodplain of the middle section of the Oka river basin.

Keywords

• floodpain
• polynomial
• Oka river
• width of the riverbed
• Mende’s Atlas
• meandering