The Peninsular Drainage System
- Drainage is the natural or artificial removal of excess surface or sub-surface water from an area. The drainage basin is the area of land drained by a single river and its tributaries. A drainage system is the pattern formed by streams, rivers and lakes in a particular drainage basin. It is governed by the topography and the gradient of land.
- All drainage systems are made of an inter-connected network of rivers and streams, which form the drainage patterns. The way rivers and their tributaries are arranged on the landscape is called drainage pattern. Factors affecting the drainage patterns are the types of underlying rocks, soil, relief, climate, and human activity. Drainages tend to develop along zones, where the rock type and structure are easily eroded. Various types of drainage patterns develop in a region. Major drainage patterns are:
- Dendritic Pattern
- Rectangular Pattern
- Radial Pattern, and
- Trellis Pattern
- The drainage system of India is mainly controlled by the broad relief features of the subcontinent. Drainage system is also affected by the nature and characteristics of precipitation. Indian drainage system may be divided on various bases, like:
- On the basis of discharge of water
- On the basis of the size of the watershed
- On the basis of the mode of origin, nature and characteristics
- Peninsular rivers are seasonal in nature as their flow is dependent on rainfall. Most of the peninsular rivers originate in the Western Ghats and flow into the Bay of Bengal. Some originate in the highlands and flow westwards. Their course is shorter and shallower as compared to the Himalayan Rivers. The intensity of erosional activities is also comparatively low because of gentler slope. Some important peninsular rivers are Narmada, Tapi, Mahanadi, Godavari, Krishna, and Kaveri. Subarnarekha and Brahmani rivers are important eastward flowing rivers. Mahi and Sabarmati are the westward flowing rivers.
- River, which is such an important resource, is getting polluted these days. The pollution is generally because of growing demand in domestic sector, municipal sector, industrial sector, and agricultural sector. A heavy load of untreated sewage from all these mentioned sectors is also a menace.
How the regime of the Himalayan rivers differ from the Peninsular rivers?Marks:3
The flow pattern of Himalayan Rivers and peninsular rivers is controlled by the climatic conditions.
The Himalayan Rivers
Ø The Ganga River: As its hydrograph shows that the flow pattern of the Ganga attains a sizeable flow in the early summer because of snow melting. Its maximum flow is either in August or September and minimum in the period of December and January.
Ø The Jhelum River: The flow pattern of Jhelum is high throughout the year, due to snow melting and rainfall in the region.
Ø The Godavari river: As its hydrograph shows that the flow pattern of Godavari river has also seasonal effects. Its flow is low until May. It has two maxims – one in May-June and the other in July-August. After August, its flow pattern falls sharply but it has higher flow in October and November also.
Ø The Narmada River: The hydrograph shows that the flow pattern of Narmada is also seasonal. It is high in the month of June to October during the rainy season. During winter it is low.
Distinguish between the East flowing rivers and the West flowing rivers.Marks:3
East flowing rivers
West flowing rivers
1. The rivers flowing eastward on the peninsular plateau are generally large.
1. The rivers flowing westward on the peninsular plateau are generally small but rivers Narmada and Tapti are exception to this.
2. These rivers form huge deltas near their mouth.
2. These rivers do not form deltas.
3. These rivers do not flow through trough.
3. West flowing rivers like Narmada and Tapi flow through troughs which have been formed due to faulting.
4. These rivers fall into into Bay of Bengal.
4. These rivers fall into Arabian Sea.
5. The Mahanadi, Godavari, Krishna and Kaveri are east flowing rivers.
5. The Narmada and Tapi are west flowing rivers.
What is an estuary?Marks:1
The tidal mouth of a river where sweet and salty waters forcibly mix together is an estuary. It is generally formed when the river falls in the sea.
What do you mean by Inland Drainage?Marks:1
When the river water falls into inland sea or lake, it is called inland drainage. Luni River in Rajasthan falls under inland drainage system.
Write the names of the basins formed by the Peninsular rivers.Marks:1
The basins formed by the Peninsular rivers are as follows:
- Betul basin (M.P.)
- Nasik basin (Maharashtra)
- Chhattisgarh basin (Chhattisgarh)
- Mahabaleshwar basin and Brahmagiri range of Western Ghats