APPARATUS, TEST PROCEDURES, AND ANALYTICAL METHODS TO MEASURE SOIL ERODIBILITY IN SITU

The assessment of the erodibility of soil materials is essential for analyzing and modeling rill, gully, streambed, streambank, spillway, and embankment erosion. A submerged jet-testing apparatus has been developed and used for characterizing soil erodibility in several applications as cited in the literature. The apparatus has been developed based on knowledge of the hydraulic characteristics of a submerged jet and the characteristics of soil erodibility. The test is simple, quick, and relatively inexpensive to perform. The test is repeatable and gives consistent results. The coefficients obtained from the test results can be used in current equations to predict erosion. This article provides a description of the apparatus, methodology, and procedures for conducting jet tests in the field. An example case is also presented to illustrate the use of test results to predict erosion in an earthen channel. The estimated average erosion, for the example case of an open channel test based on jet test results, was 15.7 cm (6.2 in.) and the measured average centerline erosion in the open channel flow test was 14.5 cm (5.7 in.).