Drainage — Social Studies STD 9 — Question

The term drainage describes the river system of an area. The streams within a drainage basin (the area drained by a single river system) form certain patterns which are given below:

1. Dendritic pattern: The dendritic drainage 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'.
2. Trellis pattern: This drainage pattern develops when a river is joined by its tributaries at approximately right angles. This drainage pattern also develops where hard and soft rocks exist parallel to each other.
3. Rectangular pattern: This drainage pattern develops on a strongly jointed rocky terrain.
4. Radial pattern: This drainage pattern develops when streams flow in different directions from a central peak or a dome-like structure.