Peninsular Drainage System

• The Peninsular Drainage system originates within the expansive Peninsular Plateau. 
• The rivers coursing through this region traverse relatively shallow valleys, which have undergone a certain degree of grading.
• Erosional activities within these rivers are minimal, characterizing them as instances of secondary drainage. 
• These watercourses have matured over time as they meander through one of the Earth's oldest plateaus.
• Peninsular rivers exhibit a significantly greater age compared to Himalayan rivers. 
• With the exception of a few rivers in the upper peninsula region, the drainage pattern in the peninsula is predominantly Concordant. 
• These rivers, characterized as non-perennial, experience their peak flow during the rainy season.
• Having reached the mature stage of Fluvial Landforms, peninsular rivers are nearing their base level. 
• They are marked by expansive, wide, and shallow valleys, with gentle slopes along their banks, except for a limited section where faulting has given rise to steep sides. 
• The Western Ghats, extending from north to south along the western coastline, serve as the principal water divide for peninsular rivers.
• Owing to a low gradient, the velocity of water in these rivers is relatively low, and the load-carrying capacity of streams is diminished. 
• The major rivers of the peninsula, such as the Mahanadi, Godavari, Krishna, and Cauvery, predominantly flow eastward and discharge into the Bay of Bengal, forming deltas at their mouths.
• In contrast, west-flowing rivers like the Narmada and Tapi, originating in the Western Ghats and flowing into the Arabian Sea, create estuaries rather than deltas due to their unique westward course. 
• This distinct geographical feature adds to the diversity of the peninsular drainage system.

• The formation of the Peninsular Drainage system is intricately tied to the geological history of the region. 
• Initially, the Sahyadri-Aravali axis served as the primary water divide, dictating the flow of rivers. 
• According to a prominent theory, the present-day peninsula is the remnant half of a larger continent, with the Western Ghats positioned at its center. 
• This geographical configuration resulted in the bifurcation of drainage, with one set of rivers flowing eastward into the Bay of Bengal, and another flowing westward into the Arabian Sea.

During the early Tertiary era, a transformative event unfolded as the western section of the Peninsula underwent fracturing and subsided beneath the waters of the Arabian Sea, a phenomenon coinciding with the formation of the Himalayas. 

This subsidence occurred due to the collision with the Indian plate, leading to rifts and troughs in select areas of the Peninsular block.

• These rifts, including faults and troughs, now serve as the courses for west-flowing rivers such as the Narmada and the Tapi. 
• This proposition gains credibility from the straight coastline, the elevated western slope of the Western Ghats, and the absence of delta formations on the western shore. 
• The unique geological history and tectonic activity in the Peninsular region have thus shaped the present-day drainage pattern, contributing to the distinct characteristics of the west-flowing rivers and the overall Peninsular Drainage system.

Important Peninsular Rivers

Rivers Flowing into the Bay of Bengal:

Mahanadi:

• Basin states: Chhattisgarh, Odisha, Jharkhand, Maharashtra, Madhya Pradesh.
• Bounded by: Central India hills (north), Eastern Ghats (south and east), Maikala range (west).
• Length: 560 km.
• Major tributaries: Seonath, Hasdeo, Mand (left bank), Ong, Tel, Jonk (right bank).

Godavari:

• Basin states: Maharashtra, Andhra Pradesh, Chhattisgarh, Odisha, Madhya Pradesh, Karnataka, Puducherry.
• Bounded by: Satmala hills, Ajanta range, Mahadeo hills (north), Eastern Ghats (south and east), Western Ghats (west).
• Length: 1,465 km.
• Major tributaries: Dharna, Penganga, Wainganga, Wardha, Pranahita (left bank), Pravara, Mula, Manjra, Peddavagu, Maner (right bank).

Krishna:

• Basin states: Andhra Pradesh, Maharashtra, Karnataka.
• Bounded by: Balaghat range (north), Eastern Ghats (south and east), Western Ghats (west).
• Length: 1,400 km.
• Major tributaries: Ghatprabha, Malprabha, Tungabhadra (right bank), Bhima, Musi, Munneru (left bank).

Cauvery:

• Origin: Brahmagiri highlands, Karnataka.
• Basin states: Tamil Nadu, Karnataka, Kerala, Puducherry.
• Bounded by: Western Ghats (west), Eastern Ghats (east and south).
• Length: 800 km.
• Important tributaries: Harangi, Hemavati, Shimsha, Arkavati (left bank), Lakshmana Tirtha, Kabbani, Suvarnavati, Bhavani, Noyil, Amaravati (right bank).
• West Flowing Rivers into the Arabian Sea:

Narmada:

• Basin states: Madhya Pradesh, Gujarat, Maharashtra, Chhattisgarh.
• Bounded by: Vindhyas (north), Maikala range (east), Satpuras (south), Arabian Sea (west).
• Length: 1,310 km.
• Right bank tributaries: Barna, Hiran River, Tendoni River, Choral River, Kolar River, Man River, Uri River, Hatni River, Orsang River.
• Left bank tributaries: Buehner River, Banjar River, Sher River, Shakkar River, Dudhi River, Tawa River, Ganjal River, Chhota Tawa River, Kaveri River, Kundi River, Goi River, Karjan River.

Tapi:

• Basin states: Madhya Pradesh, Maharashtra, Gujarat.
• Length: 724 km.
• Tributaries (right bank): Suki, Gomai, Arunavati, Aner.
• Tributaries (left bank): Vaghur, Amravati, Buray, Panjhra, Bori, Girna, Purna, Mona, Sipna.

Mahi:

• Basin states: Madhya Pradesh, Rajasthan, Gujarat.
• Bounded by: Aravalli hills (north, northwest), Malwa Plateau (east), Vindhyas (south), Gulf of Khambhat (west).
• Length: 583 km.
• Right bank tributaries: Som, Anas.
• Left bank tributaries: Panam.

Rivers Flowing into the Ganges:

Chambal, Betwa, Ken, Son, Damodar.

Significance of Peninsular Drainage:

• Rainfall-dependent, making rivers seasonal or non-perennial, limiting their suitability for irrigation.
• Shallow valleys, little erosional activity, and straight courses due to the hard granite surface.
• Estuaries formed by west-flowing rivers (e.g., Narmada, Tapi), while deltas formed by east-flowing rivers (e.g., Mahanadi, Godavari, Krishna, Cauvery).
• Unique geological features contribute to the distinct characteristics of Peninsular rivers, enhancing regional diversity.

FAQs about Peninsular Drainage System

1. What is the Peninsular Drainage System, and where does it originate?

Ans. The Peninsular Drainage System is a network of rivers originating within the expansive Peninsular Plateau.

2. How do the rivers in the Peninsular region differ from Himalayan rivers in terms of age and characteristics?

Ans. Peninsular rivers are significantly older than Himalayan rivers, exhibiting minimal erosional activity and a matured fluvial landscape.

3. What is Concordant drainage, and why is it prevalent in the Peninsular region?

Ans. Concordant drainage is a drainage pattern where rivers flow parallel to the structure of the geological terrain. In the Peninsula, except for a few rivers in the upper region, the drainage pattern is predominantly concordant.

4. What defines the mature stage of Fluvial Landforms for Peninsular rivers?

Ans. Peninsular rivers have reached the mature stage characterized by expansive, wide, and shallow valleys with gentle slopes, except for specific areas with steep sides due to faulting.

5. How has tectonic activity influenced the formation of the Peninsular Drainage System?

Ans. Tectonic activity during the early Tertiary era led to the fracturing and subsidence of the western section of the Peninsula, creating rifts and troughs. This transformation coincided with the formation of the Himalayas.

6. What role do the Western Ghats play in the Peninsular Drainage system?

Ans. The Western Ghats serve as the principal water divide, separating rivers that flow eastward into the Bay of Bengal from those that flow westward into the Arabian Sea.

7. Why do west-flowing rivers like Narmada and Tapi create estuaries instead of deltas?

Ans. These rivers originate in the Western Ghats and flow westward into the Arabian Sea, creating estuaries due to their unique westward course, contrasting with east-flowing rivers that form deltas.

8. Which are the major rivers flowing into the Bay of Bengal, and what are their characteristics?

Ans. The Mahanadi, Godavari, Krishna, and Cauvery are major rivers characterized by non-perennial flow, originating in the Peninsula and discharging into the Bay of Bengal, forming deltas.

9. Can you explain the significance of the Peninsular Drainage System in terms of water flow and landforms?

Ans. The Peninsular rivers are rainfall-dependent, making them seasonal or non-perennial. Shallow valleys, straight courses, estuaries, and deltas are distinctive landforms contributing to the region's geographical diversity.

10. How did geological history shape the present-day drainage pattern of the Peninsula?

Ans. The present-day Peninsula is believed to be the remnant half of a larger continent, with tectonic events during the early Tertiary era leading to the formation of rifts and troughs. This unique geological history contributes to the distinct characteristics of Peninsular rivers and their drainage system.