The streams within a drainage basin form certain patterns, depending on the slope of the land, rock structure and the climatic conditions of the area.
Drainage patterns are divided into four categories:
① Dendrite pattern
② Trellis pattern
③ Radial pattern
④ Rectangular pattern
① Dendrite pattern:
It consists of a single main stream with tributaries resembling the branches of a tree. It develops when the river channel follows the slope of the terrain. e.g. Ganga
② Trellis Pattern:
When tributaries join the main stream at right angles, a pattern is called trellis. A trellis drainage pattern develops where hard and soft rocks exist parallel to each other. For example the Narmada.
③ Radial Pattern:
In this pattern, the streams flow in different directions from a central peak or dome like structure forming a radial pattern.
④ Rectangular Pattern:
It develops on a strongly joint rocky terrain. In this, the main stream and its tributaries join at right angles.