Science Based Restoration to Describe Bed Microroughness in Gravel Streams

The objective of this research is to investigate the geometrical properties, and in particular the shape, of ubiquitous bed patches in gravel streams known as clusters. The inherent irregularity that clusters have, prevents their description with the traditional methods. Clusters come in different shapes, viz. line-clusters, rhomboid, triangular and are the outcome of bed reworking by the flow. Thus, we employ the fractal geometry, which uses the fractal dimension, D, for the study of the clusters. The box counting method is used for the D estimation of clusters created artificially and under laboratory conditions. The results of the study demonstrate the potential of D to quantitatively characterize the different cluster shapes and classify them in shape categories. This finding shows that the proposed technique may be used for field pattern recognition and characterization of microroughness in gravel streams. The latter is of paramount importance to modellers as well as for simulating flows over ubiquitous gravel roughness elements, such as cluster microforms.