ABSTRACT
The composition of the bed surface of a gravel-bed river is frequently coarser than that of the subsurface. This stream bed armoring is an important morphological feature since the composition, structure, and dynamics of the bed surface play defining roles in many hydraulic, geomorphic, and biologic processes. However, despite considerable effort by researchers to understand the bed surface of gravel-bed rivers, it remains a very complex feature that is difficult to define, describe, and measure, let alone model.
