A study on soil loss rate assessment of vegetation mat measures

The hydraulic stability of the high-water revetment with and without vegetation mat was tested in both laboratory-scale hydraulic experiments, as well as prototype-scale experiments. Experimental cases cover a wide range of cross-sectional average velocity (0.2 to 2.0 m/s), different slopes of the embankment, and two different types of soils. For each experimental condition, measurements of velocity field and scouring profile on the embankment were repeated for the cases with and without vegetation mat, respectively, to assess the efficiency of the vegetation mat in protecting the embankment. A dramatic reduction in soil loss rate was observed in the cases with the vegetation mat installed. The experimental results were recast in terms of Froude number and the soil loss rate appears to be proportional to the square of Froude number. Also a functional relationship between the soil loss rate and the cross-sectional average velocity was also deduced so that it could guide actual design practices of such high-water revetments. To the authors’ best knowledge, the current study is the first to attempt to provide a practical design guideline.