Аннотация:The works by the method of electrotomography (ET) were carried out on the right bank of the riverwtkm Volga. The primary goal of the work is to study the geological structure of the upper part of the section for the selection of sites for the installation of the road bridge supports. On the slope, measurements were made along 9 (10) profiles oriented across the river bed. Several profiles were made on the slope. A Syscal Pro Switch 72 multichannel station manufactured by Iris Instruments (France) was used for measurements. Interpretation of ET data was performed in 2D inversion modes (ZONDRES2D program, author – A.E. Kaminskiy, [ 2 ]) and 3D inversion (ZONDRES3D program by the same author). One of the methodological tasks was to compare the 2D and 3D results for the depth and detail of the final geoelectric model. In addition, in the course of interpretation, we estimated the equivalence of solving the inverse 2D problem, depending on the choice of the starting model.