Run (glide, plane-bed)
Stretches of uniform and relatively featureless bed, comprising bedrock or coarse clasts (cobble or gravel). These smooth flow zones are either free-flowing or imposed shallow channel-like features that connect pools. They occur in both alluvial or bedrock-imposed situations. Individual boulders may protrude through otherwise uniform flow.
Plane-bed conditions promote relatively smooth conveyance of water and sediment. Slopes are intermediate between pools and riffles.