Methodological Aspects of Studying Soil Erodibility Using Washout Technique

Abstract

Results of previous experimental assessment of soil erodibility, using the methodology of washing out model samples by a water stream at different installations (hydraulic flume, jetting unit, and water tube), were usually strongly variable. To solve this problem, a new approach to the formation of samples was elaborated. It differs from the previous one by loading the sample through a removable side wall of the horizontally placed cartridge. The layered loading and compaction of samples remains unchanged. The normal position of sample layers to the flow contrary to the parallel position practiced formerly enabled us to obtain a more uniform sample resistance to the flow. The use of a Poseidon measuring unit developed to define mean depth of the wave flow provided not only many-fold increase in the number of measurements of washout intensity during the experiment (from 1 to 14–15), but also enabled us to assess the quality of sample preparation, which increased accuracy and reliability of the study. The percentage standard deviation for erodibility was almost always lower in case of the horizontal loading as compared to the vertical one both between and within the series (by 13 and 12% on average, respectively).