Drainage System — NCERT Solutions

Differences between Radial and Centripetal Drainage Pattern:

Differences between Delta and Estuary:

Socio-economic advantages of inter-linking of rivers in India:

The inter-linking of rivers would provide the following socio-economic benefits:

1. Irrigation: Surplus water from flood-prone rivers can be transferred to drought-prone and water-deficit regions, thereby increasing the irrigated area and agricultural productivity.
2. Flood and Drought Control: It would help in controlling floods in the Ganga-Brahmaputra basin and mitigating droughts in the Peninsular and western regions simultaneously.
3. Hydroelectric Power: The canals and reservoirs created can be used to generate hydroelectric power, meeting the energy needs of the country.
4. Navigation: The inter-linked waterways can serve as inland navigation routes, reducing transportation costs and boosting trade.
5. Employment and Economic Growth: Increased agricultural output and industrial activity due to assured water supply would generate employment and promote overall economic development.

Three characteristics of Peninsular rivers:

1. Seasonal flow: Most Peninsular rivers are seasonal (non-perennial) in nature. They are fed mainly by rainfall and tend to dry up or have very little water during the dry season (summer).

2. Fixed and shallow course: Peninsular rivers flow in fixed, well-defined courses over hard rock surfaces. They have a limited capacity to change their course and are generally shallower compared to Himalayan rivers.

3. Short and swift with limited basin: Peninsular rivers are comparatively shorter in length with smaller basins. They originate from the Western Ghats or the central highlands and flow eastward or westward, covering shorter distances before meeting the sea. They do not receive glacial meltwater and hence depend entirely on monsoon rainfall.

Characteristic Features of North Indian (Himalayan) Rivers:

1. Perennial: North Indian rivers are perennial (ever-flowing). They receive water both from monsoon rainfall and from the melting of glaciers and snow in the Himalayas throughout the year.

2. Long course and large basins: These rivers originate in the Himalayas and travel long distances across the plains before meeting the sea. They have very large drainage basins (e.g., the Ganga basin covers about 8.6 lakh sq. km).

3. Antecedent drainage: Many Himalayan rivers (e.g., Indus, Ganga, Brahmaputra) are older than the Himalayas themselves. They cut through the rising mountains, forming deep gorges — a feature called antecedent drainage.

4. Heavy silt load and meandering: These rivers carry a heavy load of silt eroded from the young Himalayan mountains. In the plains, they flow slowly, deposit silt, and form meanders, oxbow lakes, and broad floodplains.

5. Delta formation: They deposit large amounts of sediment at their mouths, forming extensive and fertile deltas (e.g., the Sundarbans delta).

Differences from Peninsular Rivers:

Important rivers encountered while travelling from Haridwar to Siliguri along the Himalayan foothills:

Travelling from west to east, the major rivers one would cross are:

1. The Ganga (at Haridwar)
2. The Ramganga
3. The Gomti
4. The Ghaghra (Saryu)
5. The Gandak
6. The Kosi
7. The Mahananda (near Siliguri)

Characteristics of the Kosi River:

The Kosi is one of the most important and notorious rivers of this region. Its key characteristics are:

1. Origin: The Kosi originates in the glaciers of Tibet (near Mount Everest) and enters India through Nepal. It is formed by the confluence of several streams including the Arun, the Sun Kosi, and the Tamur.

2. Perennial river: Like other Himalayan rivers, the Kosi is perennial — it receives water from glacial melt as well as monsoon rainfall throughout the year.

3. Heavy silt load and shifting course: The Kosi carries an enormous amount of silt from the young Himalayan mountains. Due to this heavy sediment load, it constantly shifts its course. Over the past 250 years, it has shifted its course westward by about 120 km, causing widespread flooding and destruction.

4. 'Sorrow of Bihar': Because of its frequent and devastating floods, the Kosi is called the 'Sorrow of Bihar'. It inundates vast areas of the North Bihar plains every year, causing immense loss of life and property.

5. Drainage basin: The Kosi drains a large area of Nepal and the Bihar plains before joining the Ganga near Kursela in Bihar.

6. Flood plains: It forms broad, fertile flood plains in the Bihar plains due to deposition of alluvial silt, which makes the soil very productive when floods recede.