Understanding India's Drainage Systems: Peninsular vs. Himalayan

India's river systems are broadly divided into two main categories based on their origin: the Himalayan drainage system and the peninsular drainage system.

The Himalayan drainage system includes rivers that originate from the Himalayas. These are typically perennial rivers with long courses, carving deep gorges and forming large deltas. Examples include the Indus, Ganga, and Brahmaputra river systems and their tributaries like Yamuna, Ghaghra, and Gandak.

The peninsular drainage system comprises rivers flowing through the Peninsular Plateau. These rivers are generally older than the Himalayan rivers. Most are seasonal (rain-fed), have shorter courses and smaller basins compared to Himalayan rivers, and primarily flow eastward into the Bay of Bengal. Key examples include the Mahanadi, Godavari, Krishna, and Cauvery. Some exceptions like Narmada and Tapi flow westward into the Arabian Sea.

Analyzing the Options

Let's examine each group of rivers provided in the options to determine which belongs to the peninsular drainage system:

• Option 1: Gandak and Ghaghra - These are major tributaries of the Ganga river. The Ganga originates in the Himalayas, and its tributaries draining the northern plains are considered part of the Himalayan drainage system. Thus, this group belongs to the Himalayan system.
• Option 2: Mahanadi and Godavari - The Mahanadi is a major river flowing through Chhattisgarh and Odisha, draining into the Bay of Bengal. The Godavari is the largest peninsular river, flowing through Maharashtra, Telangana, and Andhra Pradesh, also draining into the Bay of Bengal. Both are characteristic rivers of the Peninsular Plateau. Thus, this group belongs to the peninsular drainage system.
• Option 3: Ganga and Yamuna - The Ganga and Yamuna are the principal rivers of the Himalayan drainage system, forming the vast Indo-Gangetic plain. They originate from glaciers in the Himalayas. Thus, this group belongs to the Himalayan system.
• Option 4: Damodar and Sarda - The Damodar river is a tributary of the Hooghly River, which is a distributary of the Ganga. While it flows through a relatively old plateau region (Chota Nagpur), it is often considered part of the Ganga basin system. The Sarda (also known as Sharda or Mahakali) is a tributary of the Ghaghra, which in turn is a tributary of the Ganga. Both are generally associated with the Himalayan drainage system or its lower basin. Thus, this group is primarily associated with the Himalayan/Indo-Gangetic system.

Based on this analysis, the group of rivers that is a part of the peninsular drainage system is Mahanadi and Godavari.

Comparing Drainage Systems

Revision Table: River Systems in India

Additional Information on Indian Drainage Systems

The peninsular drainage system is older than the Himalayan one. The general gradient of the Peninsular Plateau is from west to east, which explains why most peninsular rivers flow eastward into the Bay of Bengal. The Western Ghats form the main water divide in the peninsula. The Narmada and Tapi are notable exceptions, flowing westward through rift valleys.

The Mahanadi basin is important for its agricultural value and the Hirakud Dam. The Godavari, often called 'Dakshin Ganga', is the longest peninsular river and drains a large area of central and southern India. Understanding the characteristics of these drainage systems is crucial for studying India's geography, climate, and resource distribution.