Drainage System in India
What is drainage? And how does this drainage system works in India? On such a large scale? Let’s know more about this:
- The flow of water through well-defined channels and modes is probably known as drainage and the network of such channels in the form of the chain is known as a drainage system.
Indian Drainage Pattern
The drainage pattern of an area is basically the outcome of the geological time period, nature, and as well as the structure of rocks, topography, slope, etc. of the particular area.
A Drainage pattern can be defined in the shadow of topographical features from which a stream gets runoff, flow through, and groundwater flow which can be divided by topographic barriers are called watershed.
A watershed can be defined as all of the stream tributaries that flow to some location along the stream channel.
A geometric arrangement of streams in a region is known as a drainage pattern.
The factors controlling the pattern of drainage in a region include the topography, slope, structural control, and nature of rocks, tectonic activities, a supply of water, and above all, the geological history of that region.
Types of drainage patterns found in India
1. Discordant drainage patterns :
A drainage pattern is described as discordant if it does not correlate to the topography and geology of the area. Discordant drainage patterns are classified into the following :
1.1 Antecedent or Inconsequent Drainage
The Rivers that existed before the upheaval of the Himalayas and cut their courses southward by making gorges in the mountains are known as the antecedent rivers.
The Indus, Satluj, Ganga, Sarju (Kali), Arun (a tributary of Kosi), Tista and Brahmaputra are some of the important antecedent rivers, originating from beyond the Greater Himalayas.
1.2 Consequent Rivers
The Rivers which follow the general direction of slope are known as the consequent rivers. Most of the rivers of peninsular India are consequent rivers. For example, rivers like Godavari, Krishna and Kaveri, descending from the Western Ghats and flowing into the Bay of Bengal, are some of the consequent rivers of Peninsular India.
1.3 Subsequent Rivers
A tributary stream that is eroded along an underlying belt of non-resistant rock after the main drainage pattern (Consequent River) has been established is known as a subsequent river. Due to the northward slope of the Peninsula towards the Great Plains, the rivers originating from the Vindhyan and the Satpura ranges flow northward into the Ganga system. The Chambal, Sind, Ken, Betwa, Tons and Sone meet the Yamuna and the Ganga at right angles.
1.4 Superimposed or Super-induced Drainage
It is formed when a stream with a course originally established on a cover of rock now removed by erosion, so that the stream or drainage system is independent of the newly exposed rocks and structures. The Damodar, the Chambal, the Banas and the rivers flowing at the Rewa Plateau are some good examples of superimposed drainage.
2. Dendritic River drainage Pattern
- In dendritic pattern the River channel follows through the slope of the terrain
- This pattern develops in a terrain which has uniform lithology, and where faulting and jointing are insignificant.
- Streams run in all directions without definite preference to any one particular region
- Examples of dendritic pattern are Indus, Godavari, Mahanadi, Cauvery, Krishna
3. Rectangular River drainage Pattern
- The drainage pattern marked by right-angled bends and right-angled junctions between tributaries and the main stream is known as rectangular drainage.
- It differs from the trellis pattern in so far as it is more irregular and its tributary streams are neither as long, nor parallel as in trellis drainage.
- A typical example of this drainage pattern is found is the Vindhyan Mountains of India.
- The rivers provide uniform resistance to erosion and Develops on strongly joined rocky terrain
4. Trellis River drainage Pattern
- This pattern develops in folded topography; alternate layers of hard & soft rocks.
- It is a rectangular pattern formed where two sets of structural controls occurs at right angles.
- In a trellis pattern, the river forms a net like system and the tributaries flow roughly parallel to each other.
- Longer streams have preference to one direction
- The old folded mountains of the Chotanagpur Plateau have drainage of trellis pattern.
5. Radial River drainage Pattern
- It is a pattern characterized by out flowing rivers, away from a central point, analogous with the spokes of a wheel. It tends to develop on the flanks of a dome or a volcanic cone.
- A good example of a radial drainage pattern is provided by the rivers originating from the Amarkantak Mountain. Rivers like Narmada, Son and Mahanadi originating from Amarkantak Hills flow in different directions and are good examples of radial pattern.
- This pattern is also found in the Girnar Hills (Kathiwar, Gujarat), and Mikir Hills of Assam.
6. Pinnate River drainage Pattern
- Pinnate pattern is developed in a narrow valley flanked by steep ranges.
- The tributaries originating from the steep sides of parallel ridges join the longitudinal master consequent occupying the valley at acute angles
- The drainage network of the Narmada rivers denotes the example of pinnate drainage pattern. This pattern resembles the veins of a leaf.
7. Parallel River drainage Pattern
- The drainage pattern in which the rivers flow almost parallel to each other is known as parallel drainage.
- The small and swift rivers originating in the Western Ghats and discharging their water into the Arabian Sea provide a good example of parallel drainage pattern in India.
8. Annular river drainage Pattern
- In this drainage pattern, the subsequent streams follow curving or actuate courses prior to joining the consequent stream.
- This results from a partial adaptation to an underground circular structure; a dome like igneous intrusion (batholith).
- The subsequent streams find it easier to erode the concentric, less resistant strata.
- This is not a very common drainage pattern in India. Some examples of this are however found in Pithoragarh (Uttarakhand), Nilgiri Hills in Tamil Nadu and Kerala.
9. Deranged river drainage Pattern
- This is an uncoordinated pattern of drainage characteristic of a region recently vacated by an ice-sheet.
- This is probably due to the irregularities produced by glacially deposited materials, e.g., Kame and Kettle, and by the fact that there has been insufficient time for the drainage to become adjusted to the structures of the solid rock underlying the glacial drift.
- This type of drainage is found in the glaciated valleys of Karakoram.