Probably the most common and extensive river pattern is dendritic or tree-shaped. A tree has branches and twigs. The river has tributaries and sub-tributaries finishing in the source region as first-order streams. A tree has a stem. A stream has a middle section of its course as a single major channel. A tree has roots and rootlets divergent from the base of the stem. A river has distributaries and sub-distributaries.
Thus the analogy between a tree and a dendritic river or river system is comprehensively striking. Dendritic pattern will be found to be the most common in all climates, topographies, structures and on all scales in any part of the world. This is strikingly true of India also. It can be seen in the vast Indo-Gangetic plains and the peninsular region except the coastal margins. It is also one of the dominant patterns in the Himalayas.
This universality of the dendritic pattern is due to the tendency of all drainage to integrate in relatively short geological time. Drainage courses multiply in course of time with increasingly concentrated or channelized flow. The multiplication of channels generally takes the form of tributaries or ‘branches’. Integration is also effected by stream captures. Tame flat still stand topography encourages dendritic pattern because under such conditions the streams have no decisive directions. They wander under slightest deflective causes and go on uniting into larger streams.
Therefore, low-level erosion surfaces will be dominated by dendritic pattern, e.g., the Peninsular peneplains, particularly the Mahanadi, Godavari, Krishna, the Damodar and the Cauvery basins. In depositional plains, the surface is more flat and dominated by dendritic pattern. Structural guidance is practically nil. Thus, the dominant pattern in the Indo-Gangetic plain is dendritic. In plains of desertification erosion under arid conditions, deflation and aeolian deposition the pattern is dendritic, e.g., Rajasthan desert. The pattern is also markedly dendritic in glaciated lowland as in North European plains and northern lowlands of North America.