ACCUMULATIVE AND EROSION PROCESSES ON THE LEFT-BANK TRIBUTARIES OF THE MIDDLE VOLGA

Abstract

The article disсusses the results of monitoring observations on the rivers of the Nizhny-Novgorod TransVolga region – Kerzhenets and Bolshaya Kokshaga, flowing in the reserves having the same names. The purpose of theresearch was to identify the development patterns of floodplain-channel complexes of small rivers under the influence ofgeneral and local natural factors. The morphological appearance and evolution of floodplain-channel complexes of largerivers is influenced by large-scale zonal and regional factors, which manifest themselves over large areas. Small rivers,while developing according to the same laws of riverbed processes, are also affected by local factors, which cause theirevolution to deviate from the development patterns of large rivers. We deem it possible to systematize local factors in thesmall rivers’ development and take them into account when forecasting their evolution. Thus, the specific purpose of thisarticle is to identify and systematize the factors influencing the development of small rivers.The research methodology is based on annual observations of the condition of the riverbeds and floodplains in freemeandering areas, typical for small rivers. The paper analyzes annually measured bank erosions in different sections ofbends of different curvature as well as the relationship between the intensity of erosion and the water content of floods;changes in the near-bank parts of the floodplains of the rivers are traced. The study has established a relationship betweenthe bank erosion intensity and the water level rise during high water periods, systematized and typified small factorsaffecting channel deformations, and established how certain groups of these factors influence the evolution of the riverbed. In the future, it is recommended to continue a series of observations of the dynamics of the riverbeds in order toclarify the influence of local factors on different types of free bends, as well as to try to detect cyclicity in their changes,which cannot be done on large rivers because of their size and high energy flow.