Is there a particle size classification standard that is widely accepted?
High particle size variability is a common trait of many natural rivers. The range of particle sizes in a river may span five orders of magnitude. Consequently, the properties of an individual particle are largely irrelevant, and the behavior and characteristics of groups of particles takes on increased significance. For this reason, it is both necessary and convenient to group sediments into different size classes. As a result, numerous classification systems have developed. Most are essentially arbitrary and can be found in the engineering, geologic, and fisheries literature. Most are based on the metric system; however, a few early classification approaches used English units. The table on the following page shows some of the most commonly used particle size classification systems and allows ready comparison among them. Note that there is a remarkable degree of similarity between the various systems especially with respect to size class breaks. Most differences are related to nomenc
