Drainage Patterns

The streams within a drainage basin form certain patterns, depending on the slope of the land, underlying rock structure as well as the climatic conditions of the area.
• These are described as follows:
o Dendritic Drainage: The dendritic pattern develops where the river channel follows the slope of the terrain. The stream with its tributaries resembles the branches of a tree, thus the name dendritic. A pattern of drainage that is branching, ramifying or dichotomizing, thereby giving the appearance of a tree. Most of the rivers of the Indo-Gangetic Plains are of dendritic type.
o Trellis Drainage: A river joined by its tributaries, at approximately right angles, develops a trellis pattern. A trellis drainage pattern develops where hard and soft rocks exist parallel to each other. In a trellis pattern, the river forms a net-like system and the tributaries flow roughly parallel to each other. The old folded mountains of the Chotanagpur Plateau have drainage of trellis pattern.
o Rectangular Drainage: It is marked by right-angled bends and right-angled junctions between tributaries and the mainstream. It differs from the trellis pattern in so far as it is more irregular and its tributary streams are neither as long, nor parallel as in trellis drainage. A rectangular drainage pattern develops on a strongly jointed rocky terrain. A typical example of this drainage pattern is found in the Vindhyan Mountains of India. o Radial Pattern: The radial pattern develops when streams flow in different directions from a central peak or dome-like structure. A good example of a radial drainage pattern is provided by the rivers originating from the Amarkantak Mountain. Rivers like Narmada, Son and Mahanadi originating from Amarkantak Hills flow in different directions. This pattern is also found in the Girnar Hills (Kathiwar, Gujarat), and Mikir Hills of Assam.