Past studies have demonstrated the relation between channel-perimeter sediment type (i.e., the weighted mean percent silt-clay in the channel and banks, M) and channel shape (i.e., the width-depth ratio). Moreover, M was found to be an indicator of the predominant sediment transport mode. Motivated by the reasoning and results of this earlier work we propose a classification scheme for single thread rivers that relies on the median bed material grain size (D50) to classify streams as predominantly transporting either a fine suspended load (D50<=0.062mm), coarse suspended load (0.062mm<D50<=0.50mm), mixed load (0.50mm<D 50<=25.0mm), or bedload (D50>25.0mm). For classifying channels, we use Shields curve to define conditions of incipient sediment motion and the criterion u*=ws (u *=shearvelocity and ws=sedimentfallvelocity) to define the onset of significant suspended load transport. This work is warranted because in most studies of rivers and canals the D50, rather than M, is the only measure recorded for describing channel-perimeter sediment type. Distinctive relationships between Bbf and Qbf, and H bf and Qbf are noted for each of the stream classes we propose, that is, trendlines for these variable differ systematically between stream classes. In contrast, width-to-depth ratios for the stream classes are not distinctive; the width-to-depth ratios range from 3 to 100 across all stream types and values as large as 1,000 are common for coarse suspended-load streams.