In terms of geological divisions, peninsular rivers of India are generally distributed over of the Chotanagpur region, the Maharashtra region, the Chhattisgarh region, the Odisha Highland region, Dandakaranya, the Karnataka Plateau, the Andhra Plateau, the Tamil nadu Uplands and South Sahyadri, the West Coast region, and the East Coastal Plains.
The numerous rivers of peninsular India that flow through peninsular India have certain areas that form the catchment of these rivers. Catchment areas are basins of water formed by the river and its tributaries that are interlinked and can cover very large areas.
These catchment areas can be contiguous and it takes a significant geological division to separate these catchment areas into two separate catchment areas for the rivers of peninsular India. While Himalayan rivers are fed by melting snow, springs and rainfall, and are usually perennial, peninsular rivers are usually completely rain-fed, and their discharge lowers in the dry season.
The following are some of these geological divisions that separate the catchment areas of the rivers of peninsular India. Given the innumerable number of rivers in peninsular India, the focus is on the geological divisions between some of the major river basins in peninsular India. The river basins are divided into the major catchment areas demarcated by the Central Water Commision (CWC) in their River Basin Atlas of India, as given in Figure 1.
Fig 1: Major river basins of India
Source: River basin atlas of India, CWC and ISRO, 2012
The Godavari Basin | Number 3 in Fig 1
The Godavari basin includes the states of Chhattisgarh, Maharashtra, Odisha and Andhra Pradesh and also includes smaller parts of Karnataka, Puducherry and Madhya Pradesh and occupies a total area of 3,12,812 sq km. The Godavari basin is separated from the Narmada basin by the Mahadeo Hills in the north.
The Mahadeo Hills consist mostly of small plateaus and steep scarps formed during the Carboniferous period between 360 to 300 million years ago. Mostly consisting of deciduous forests, the Mahadeo Hills although is the site for lumbering activity.
The Godavari basin is separated from the Mahanadi basin in Chhattisgarh by highlands such as the Bastar Hills and the Parasgaon Plateau towards the basin’s northern regions. The Balaghat Range in the south and the Eastern Ghats in the west separate the Godavari basin from the Krishna basin. The Sahyadri Parvat Range in the north separates the Godavari basin from the Tapti basin.
Fig: Bastar Hills and Parasgaon Plateau in Chhattisgarh
The Krishna Basin | Number 4 in Fig 1
The Krishna basin includes the states of Karnataka, Maharashtra and Andhra Pradesh and occupies a total area of 2,58,948 sq km. The Krishna basin is separated from the Godavari basin by the Balaghat Range in the north and the Eastern Ghats towards the east.
The Balaghat Range has elevations between 1,800 to 2,700 feet that diminish eastwards. The Balaghat range forms the watershed between the Godavari river in the north and the Bhima river in the south. The range is flush with vegetation westwards but relatively more barren eastwards. The Eastern Ghats in Odisha rise to an elevation of about 3,600 feet and are remnants of an ancient hill range in eastern peninsular India.
Fig: The Balaghat Ranges
Source: R. Gore & S. Gaikwad, 2015
The Cauvery Basin | Number 5 in Fig 1
The Cauvery basin includes the states of Karnataka, Kerala, Tamil Nadu and Puducherry occupying an area of 81,155 sq km. The Cauvery basin is separated from the Krishna basin by ridges that are located towards its northern region.
The ridges also separate the Cauvery basin from the Pennar basin in the north. The waters of the Cauvery rise on the Brahmagiri Hills of the Western Ghats and is considered a sacred river in South India. The Cauvery is revered by Hindus as Dakshina Ganga or the Ganges of the South.
Fig: The Cauvery in Mekedatu
The Subernarekha Basin | Number 6 in Fig 1
The Subernarekha basin includes the states of Jharkhand and Odisha and occupies an area of 29,196 sq km. Ridges separate the Subernarekha basin from the Baitarani basin in the south.
The Kasai Valley separates the Subernarekha basin from its eastern regions. The Chota Nagpur Plateau separates the Suberanrekha basin from the Brahmani and Baitarni basin in the west.
The Chota Nagpur Plateau is made up of Precambrian rocks dating back to about 540 million years. Chota Nagpur is the collective name for the Ranchi, Hazaribagh and Kodarma Plateaus and has an average elevation of about 2,300 feet. The uplands are dissected into a peneplain by numerous rivers.
Fig: Dassam Falls of Kanchi River in the Chota Nagpur Plateau – a tributary of Subarnarekha
The Brahmani and Baitarni basin | Number 7 on Fig 1
The Brahmani and Baitarni basin includes the states of Chhattisgarh, Jharkhand and Odisha and occupies an area of 51,822 sq km. The Chhotanagpur Plateau separates the Brahmani and Baitarni basin from the Subernarekha basin in the north east.
A ridge separates the Brahmani and Baitarni basin from the Mahanadi basin in the south-west. The Brahmani river is formed by the confluence of the South Koel and Sankh rivers. The Brahmani cuts across the Eastern Ghats and forms a gorge at Rengali in Odisha, where the Rengali Dam is situated.
Fig: The Chota Nagpur Plateau
Source: Oxford School Atlas
The Mahanadi Basin | Number 8 on Fig 1
The Mahanadi basin includes the states of Odisha and Chhattisgarh and occupies an area of 1,41,589 sq km. The Mahanadi basin is separated from the Godavari basin by the Eastern Ghats towards the south.
The Maikala Range in the west separates the Mahanadi basin from the Narmada basin. The Maikala Range runs north to south with elevations ranging between 2,000 to 3,000 feet. The range mostly consists of flat-topped plateaus capped with laterite soil.
Vegetation in the range can alternate between thorny trees and grass to deciduous forests. A ridge separates the Mahanadi basin from the Brahmani and Baitarni basin.
Fig: The Maikala Hills
The Pennar Basin | Number 9 on Fig 1
The Pennar basin includes the states of Karnataka and Andhra Pradesh and occupies an area of 55,213 sq km. The Pennar basin is separated by a narrow ridge from the Vedavati Valley of the Krishna basin in the west. The river Pennar rises in the Nandi Hills.
The basin lies in the rain shadow of the Eastern Ghats thus receiving about 500 mm of annual rainfall on average.
Fig: Pennar river at Gandikota
Source: Niranjan M, flickr
The Tapti Basin | Number 13 on Fig 1
The Tapti basin includes the states of Gujarat, Maharashtra and Madhya Pradesh and occupies an area of 65,145 sq km. The Tapti basin is separated from the Narmada basin by the Satpura Range in the north.
The word ‘Satpura’ in the name for the Satpura Range stands for Seven Folds, and can reach maximum elevations of more than 4,000 feet. The Satpura Range includes the Mahadeo Hills, the Maikala range and the Rajpipla Hills.
The landscape is mostly forested and consists of dissected plateaus. The Sahyadri Parvat Range separates the Tapti basin from the Godavari basin in the south.
Fig: The Satpura Hills
Source: Aditya Sahay, flickr
The Narmada Basin | Number 12 on Fig 1
The Narmada basin includes the states of Gujarat, Maharashtra, Madhya Pradesh and Chhattisgarh and occupies an area of 98,796 sq km. The Narmada basin is separated by the Maikala Range from the Mahanadi basin in the east.
The Satpura Range and the Mahadeo Hills separate the Narmada basin from the Tapti basin in the south. The Mahadeo Hills in the south also separate the Narmada basin from the Godavari basin.
In ancient and medieval times, the Narmada river was an important transit route from the Great Northern Plains to the Arabian Sea. River Narmada though is marked by numerous waterfalls as it transits the highlands and its the basin sometimes causes floods in the valleys between the hill ranges.
Fig: The river Narmada at Jabalpur
Source: Chandravir Singh, flickr