FIELD STUDIES OF THE OKA RIVER BANK EROSION IN 2014–2018 BY THE EROSIONAL PINS METHOD

Abstract

In 2014–2018, within the middle part of the Oka River basin, on narrowed and widened sections of its floodplain, were conducted studies of the retreat rate of the channel steep banks. The method of erosional pins was used to determine the rate of changes in the floodplain edge contours on active bank slopes – sections of the relatively straight and meandering Oka channel. We established that in 2014–2017, with low floods, at the level of the lower and middle intervals of channel-forming discharges, lateral erosion was determined not so much by fluvial relief formation as by slope and anthropogenic processes. After the recession of the 2018 flood, which was close in its level and discharge to the average annual values, there was a significant intensification of the bank retreat under the direct influence of the flow and more frequent formation of hollows. The annual data and integrated research results over the five-year period indicate a significant predominance of longitudinal horizontal channel deformations and a slowdown in the rate of transverse deformations, especially in dry years. The significant role of the anthropogenic and slope components in lateral erosion of the Oka channel banks has been established.