Knowing The Various Drainage Patterns

Over time, a stream system tends to achieve a particular drainage pattern to its network of stream channels and tributaries, influenced by local geologic factors. Drainage patterns or nets can be classified on the basis of their form and texture. Their shape or pattern always develops in response to what the local topography and subsurface geology is. Drainage channels develop where surface runoff is enhanced and where earth materials provide the least resistance to erosion. The texture is governed by soil infiltration and the volume of water that is available in a given period of time for entering the surface. If the soil has a moderate infiltration capacity and a less amount of precipitation strikes the surface over a given period of time, then the water is likely to be soaked in rather than to evaporate away. If a large amount of water strikes the surface then more water will evaporate, soaks in the surface, or ponds on the level ground. On sloping surfaces this surplus water will runoff. Fewer drainage channels will develop at places where the surface is flat and the soil infiltration is high as the water will soak in the surface. The fewer the number of channels, the coarser will be the drainage pattern that is formed.

A Summary Of Various Types Of Drainage Patterns

Dendritic drainage pattern- this is the most common form and looks like the branching pattern of roots of a tree. It is found to develop in regions underlain by homogeneous material.

Parallel drainage pattern – this form is found in places where there is a pronounced slope to the surface. A parallel pattern can also develop in regions of parallel, elongate landforms like out-cropping resistant rock bands.

Trellis drainage pattern – this pattern looks similar to its namesake, the common garden trellis. Trellis drainage is found to develop in folded topography like that found in the Appalachian Mountains of North America.

Rectangular drainage pattern – this is found in regions, which have undergone faulting. Streams follow the path of least resistance and so are concentrated in places were the exposed rock is the weakest. 

Radial drainage pattern – it develops around one central elevated point. This pattern is very common to such conically shaped features like volcanoes.

Centripetal drainage pattern – this is just the opposite of radial pattern mentioned above. As the streams flow toward a central depression. This pattern is typically found in the western and southwestern portions of the United States where the basins exhibit interior drainage.

Deranged or contorted pattern - this develops from the disruption of a pre-existing drainage pattern.

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