A wide variety of river and stream channel types exist in limnology, the study of inland waters. All these can be divided into two groups by using the water-flow gradient as either low gradient channels for streams or rivers with less than two percent (2%) flow gradient, or high gradient channels for those with greater than a 2% gradient.
See also: Channel patterns
Low gradient channels of rivers and streams can be divided into braided rivers, wandering rivers, single thread sinuous rivers (meandering), and anastomosing rivers. The channel type developed depends on stream gradient, riparian vegetation and sediment supply. Braided rivers tend to occur on steeper gradients where there is a large supply of sediment for braid bars, while single thread sinuous channels occur where there is a lower sediment supply for point bars. Anastomosing channels are multithreaded, but are much more stable than braided channels and commonly have thick clay and silt banks and occur at lower gradients of stream bed. Wandering rivers fall between sinuous single thread and braided streams and are relatively stable multi-channel gravel bed rivers.
High gradient channels of rivers and streams have been divided into riffle-pool (which can cover all of the low gradient channel morphologies discussed above), rapid/plane bed, step-pool and cascade unit morphologies.