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STREAM DRAINAGE PATTERNS
Dendritic: Irregular pattern of channels that branch like a tree. Rectangular: Channels have right-angle bends developed along
Develops on flat lying or homogeneous rock. perpendicular sets of rock fractures or joints.
Radial: Channels radiate outward like spokes of a wheel from a Centripetal: Channels converge on the lowest point in a closed
high point. basin from which water cannot drain.
Annular: Long channels form a pattern of concentric circles Trellis: A pattern of channels resembling a vine growing on a
connected by short radial channels. Develops on eroded domes trellis. Develops where tilted layers of resistant and nonresistant
or folds with resistant and nonresistant rock types. rock form parallel ridges and valleys. The main stream channel
cuts through the ridges, and the main tributaries flow along the
valleys parallel to the ridges and at right angles to the main
stream.
Deranged: Channels flow randomly with no relation to underlying
rock types or structures.
FIGURE 11.2 Some stream drainage patterns. Note their relationship to bedrock geology.
Stream Processes, Landscapes, Mass Wastage, and Flood Hazards ■ 287
