SENIOR SECTION
DEPARTMENT OF SOCIAL SCIENCE
CLASS: IX - GEOGRAPHY
CHAPTER:3 : DRAINAGE
Drainage means the river system in a particular area. A river system consists of the total area covered by the tributaries and other water bodies that join the main river.
The largest river basin in the world is the Amazon river basin. Drainage systems in India can broadly be categorized as Himalayan rivers and Peninsular rivers. The Himalayan rivers are fed by the snow melting from the mighty Himalayas and also seasonal rains, and hence these are perennial rivers. The four main drainage patterns are: Dendritic Drainage, Rectangular Drainage, Trellis Drainage and Radial Drainage.
Lakes are important for various reasons, like regulating the flow of river water, storage of water during the dry seasons, to maintaining the eco-system, and also the generation of hydroelectric power. The different types of lakes in India are freshwater lakes and salt water lakes. The Wular Lake in Jammu and Kashmir is the largest freshwater lake in India.
The Chilika Lake in Orissa is the largest brackish water lake in India.
Rivers are considered the most basic natural resources required for human settlement. The primary reason is that we depend on rivers for fresh drinking water and water for irrigation. River water is also used for generating hydroelectric power.
The growing demand for water in agriculture, industry and domestic use is affecting the quality of water. There has been some government action to counter this by launching activities such as the National River Conservation Plan (NRCP) and the Ganga Action Plan (GAP) introduced in 1985.
Question
1 Define the terms: Drainage, Drainage Basin, Water Divide
Drainage: describes the river system of an area.
Drainage Basin: The area drained by a single river system
Water Divide: Any elevated area, such as a mountain or upland, separates two drainage basins.
2 Differentiate between Himalayan rivers and Peninsular rivers.
3 Describe the following drainage patterns with suitable diagrams:
a) Dendritic b) Trellis c) Rectangular d) Radial
a) Dendritic: develops where the river channel follows the slope of the terrain.
The stream with its tributaries, resembles the branches of a tree
b) Trellis: A river joined by its tributaries , at app. right angles
c) Rectangular: develops on a strongly jointed rock y terrain
d) Radial: develops when streams flow in different directions from a central peak and dome-like structure.
5 Describe the Indus river system under the following headings:
a) Origin :
b) Tributaries joining in the Kashmir region :
c) Mouth of the river :
d) Tributaries of the main river :
e) Slope:
f) Length :
g) States of India in which 1/3rd basin is located:
6 Describe the Ganga river system under the following headings:
a) Headwaters of the Ganga : called the Bhagirathi is fed by the Gangotri glacier and joined by the Alaknanda at Devaprayag in Uttaranchal.
b) Place where Ganga emerges from the mountains on to the plains - Haridwar
c) Tributaries joining the river from the Himalayas : Yamuna, Ghaghara, Gandak and Kosi
d) Origin of river Yamuna and where it meets River Ganga : Rises in the Yamunotri glacier and meets the Ganga at Allahabad.
e) Tributaries rising in Nepal Himalaya : Ghaghara, Gandak and Kosi
f) Two implications of rivers rising from Nepal : i) they flood parts of the northern plains every year causing widespread damage to life and property.
ii) enrich the soil for the extensive agricultural lands.
g) Main tributaries from the peninsular uplands : Chambal, Betwa and Son
h) Characteristics of these tributaries : They rise from the semi-arid areas, have shorter courses and do not carry much water in them.
i) Northernmost point of Ganga delta : Farakka in West Bengal
j) Name of a Distributary that flows through the deltaic plains : Bhagirathi-Hooghly
k) Mouth of the river Ganga and name of its delta. :Bay of Bengal; Sunderban
i) Two characteristics of Sunderban delta : i) It is the world’s largest and fastest growing delta ii) It is also the home of the Royal Bengal Tiger
j) Length of the river: 2500 km.
k) Slope of the river: The plains form Ambala to the Sunderban stretch over nearly 1800km.,but the fall in slope is hardly 300 mt.There is a fall of just 1mt. for every 6 km.
l) Place of water divide between Indus and Ganga river systems : Ambala
m) Feature formed by the river : Large meanders
7 Describe the Brahmaputra river system under the following headings:
a) Origin : rises in Tibet east of Mansarowar lake
b) Length : slightly longer than Indus
c) How and where does it enter into India? : On reaching the Namcha Barwa,it takes a ‘U’-turn and enters India in Arunachal Pradesh through a gorge.
d) Name of the river in Arunachal Pradesh: Dihang
e) Names of its tributaries in Assam : Dibang, Lohit, Kenula
f) Name of Brahmaputra in Tibet and Bangladesh : Tsang Po in Tibet and Jamuna in Bangladesh
g) Brief note on braided channel : It has a braided channel in its entire length in Assam and forms many riverine islands.
h) Reasons for floods in Assam and Bangladesh :
i)Every year during the rainy season, the river overflows its banks, causing widespread devastation due to floods in Assam and Bangladesh.
ii) Unlike other north-Indian rivers, the Brahmaputra is marked by huge deposits of silt on its bed causing the river bed to rise.
iii) The river also shifts its channel frequently.
Please click on below link to download CBSE Class 9 Social Science Drainage Worksheet Set B
