Determinent of drainage pattern of a …

An area drained by a single river is called its drainage basin or catchment area. It includes the various streams, tributaries and sub tributaries that join to create a network of the river. Thus the main river of an area along with its tributaries forms a drainage pattern. The pattern that is formed is dependent on the relief and the rocks that make up the surface of the area. It is logical that water will flow from higher to lower area and while doing so, it will cut through the surface of the land.
The three main types of drainage patterns that can be identified are dendritic, trellised and radial.

Dendritic drainage pattern: The name is derived from the Greek word dendron which means a 'tree'. This drainage pattern is similar to a branching tree and hence the name. This pattern of flow of streams and rivers develops in an area which comprises rocks with a uniform structure.

Trellised drainage pattern: It is a rectangular shaped drainage pattern that develops where bands of rocks vary in resistance. In some areas there are alternate bands of hard and soft rocks. The flowing water can erode the soft rocks and thus flows along the bands of soft rock. Many such water channels form a trellis.

Radial drainage pattern: It is a 'spoke- like' pattern. Water channels flow from around the top if a hill or the top of a dome type feature in numerous directions like the spokes of a wheel. Such a pattern of drainage may develop from a volcano or conical mountain.