EXERCISE

1. What are the physiographic divisions of Assam?
Answer: Physiographically, Assam can be divided into four main divisions:

1. Brahmaputra Valley
2. Barak Valley
3. Karbi Plateau
4. Barail and Southern Hills

2. What are the physiographic regions of the Brahmaputra Valley?
Answer: The Brahmaputra Valley can be divided into four distinct physiographic units from north to south:

1. The Northern foothills
2. The North and South bank plains
3. The floodplain and charlands
4. The Southern foothills

3. Write four names each of the north-bank and south-bank tributaries of the Brahmaputra river.
Answer: North-bank tributaries: Subansiri, Jia Bharali, Pagladiya, Manas

South-bank tributaries: Burhi Dihing, Disang, Dikhow, Dhansiri

4. Give a brief description of the Brahmaputra plain region.
Answer: The Brahmaputra plain includes both the north and south bank plains of the Brahmaputra river. It was formed by the deposition of alluvial sediments carried by the Brahmaputra and its many tributaries from the surrounding hills. This region is very fertile and suitable for agriculture, making it thickly populated with a developed transport system. The north bank plain is relatively wide in the lower part and narrow in the upper part. The south bank plain is narrow in the western part but becomes wider towards the east due to headward erosion by rivers.

5. Give a brief description of the floodplain region of the Brahmaputra.
Answer: The floodplain region of the Brahmaputra is the area between the north and south bank plains where the river frequently floods. It includes the charlands (sandbars) that develop on the riverbed. The width of the floodplain varies and is generally narrow on the south bank. The Brahmaputra is known for its high water and sediment discharge, which causes frequent bank erosion and floods in this region, making it a critical problem for Assam.

6. Write about the geographic location and origin of Majuli.
Answer: Majuli is a permanent island located in the middle of the Brahmaputra river. It is known as one of the largest riverine islands in the world. It was formed by the deposition of sediment in the river channel. The island is located in the Brahmaputra river, with a land area of approximately 422 km2 (as per the 2011 census) and has been declared a district of Assam.

7. Write briefly about the boundaries and characteristics of the Barak Valley.

Answer: The Barak Valley is an important physiographic region of Assam. It consists of the Barak plain and its adjacent northern and southern foothills. The valley is enclosed by hill ranges on three sides: the Meghalaya Plateau and the Barail ranges to the north, the Manipur hills to the east, and the Mizo hills to the south. The plain, also known as the Cachar plain, was formed by the deposition of alluvial sediments carried by the Barak river and its tributaries. It is open to the west, where it merges with the plains of Bangladesh.

8. Write briefly about the boundaries and characteristics of the Karbi Plateau.
Answer: The Karbi Plateau is geologically part of the Meghalaya Plateau. It is divided into two parts by the Kopili valley: an eastern part (Rengma hills) and a western part. The plateau is characterized by its average height of 900 m, with the western part sloping from southwest to northeast. Its physiography is a result of the work of the Kopili and Barapani rivers and their tributaries.

9. Write briefly the characteristics of the Barail Range and Southern Hills.
Answer: The Barail Range extends westward from Thensang across Nagaland and connects the Naga hills with the Meghalaya Plateau. This range divides the North Cachar Hills district into two parts: a north-sloping part that falls within the Brahmaputra valley and a south-sloping part within the Barak valley. The southern hills of Assam also include the foothills of the Patkai-Naga hills along the border of several districts in Upper Assam.

10. What is the type of Assam’s climate? Write briefly about its characteristics.
Answer: Assam has a subtropical monsoon climate. It is characterized by heavy rainfall in the summer, dry conditions in the winter, and high humidity and relatively low temperature throughout the year. The climate is influenced by the monsoon winds and the state’s diverse topography, which causes temperature and rainfall to vary from place to place.

11. What is the main reason behind occurrence of rainfall in Assam during summer season.
Answer: The main reason for rainfall in Assam during the summer season is the moist South-West Monsoon wind. This wind, originating from the Bay of Bengal, is obstructed by the Himalayas and other surrounding hills, leading to orographic and cyclonic rainfall processes.

12. Discuss briefly about the geographical factors influencing the climate of Assam.
Answer: The climate of Assam is influenced by several geographical factors:

1. Location: Its location in the subtropical region and its position between South and Southeast Asia.
2. Topography: The presence of the Himalayan mountain range to the north and east protects the state from cold winter winds from Tibet.
3. Proximity to Water Bodies: The proximity to the Arabian Sea, Bay of Bengal, and the Indian Ocean, which are the sources of the moist monsoon winds.
4. Local Factors: The presence of local winds like mountain and valley winds, as well as rivers and wetlands, which influence local climate characteristics.

13. What are the main seasons of Assam? Write in brief about the seasonal variation in the distribution of temperature and rainfall in Assam.
Answer: The four main seasons of Assam are Pre-Monsoon, Monsoon, Retreating Monsoon, and Dry Winter.

1. Pre-Monsoon (March-May): Temperature and rainfall begin to increase. Unstable atmospheric conditions cause sudden rainstorms with thunder and lightning.
2. Monsoon (June-September): This is the main rainy season, with moderate to heavy rainfall. About 70% of the total annual rainfall occurs during this time, leading to frequent floods.
3. Retreating Monsoon (October-November): Temperature and rainfall decrease. Wind direction reverses, blowing from the northeast.
4. Dry Winter (December-February): Temperatures are low, with mornings often foggy. There is very little rainfall, and the air is dry.

14. Write the names of place in Assam witnessing the highest and lowest rainfall along with their amount of rainfall.
Answer: Highest Rainfall: The place in Assam that records the highest annual rainfall is North Lakhimpur, which receives around 335 cm of rainfall each year.

Lowest Rainfall: The lowest average annual rainfall is Lanka-Lumding region of Nagaon district which receives around 129 of rainfall each year.

15. Why does the amount of rainfall not uniform in all places of Assam?
Answer: The amount of rainfall is not uniform across Assam due to several factors. The topography, including the surrounding hills and mountains, plays a major role by obstructing monsoon winds. This leads to heavy rainfall on the windward side of the hills (where the wind hits) and significantly less rainfall on the leeward side (the side away from the wind). Local factors also influence rainfall patterns.

16. Write in brief about the spatial distribution of rainfall in Assam.
Answer: The spatial distribution of rainfall in Assam is uneven. It is generally higher in the hills and foothill areas. Annual rainfall exceeds 250 cm in the districts of Upper Assam (Tinsukia, Dibrugarh, Dhemaji, Lakhimpur, Sivasagar) and Lower Assam (Kokrajhar, Dhubri), as well as in the southern part of Assam (Cachar, Karimganj, Hailakandi). In contrast, central Assam districts like Nagaon and Karbi Anglong receive significantly less rainfall.

17. Give a short account of different types of soil found in Assam.
Answer: The soils of Assam are formed by the interaction of parent materials, climate, and physiography. They can be classified into four types:

1. Alluvial Soil: Found extensively in the plains of the Brahmaputra and Barak valleys. They are fertile and are divided into new (in floodplains) and old alluvial soils.
2. Piedmont Soil: Located in the narrow zone along the Himalayan foothills, consisting of the Bhabar and Tarai belts.
3. Hill Soil: Found in the southern hill areas. These soils have varying fertility and can be categorized into red sandy soils and red loamy soils.
4. Laterite Soil: Found in the Dima Hasao district and parts of the Karbi Plateau. They are black and sandy with low amounts of essential nutrients.

18. What are the reasons behind soil erosion in Assam?
Answer: Soil degradation and erosion in Assam are caused by both physical and human factors.

1. Physical factors: Natural causes like soil erosion on hill slopes and waterlogging on the plains.
2. Human factors: These are more active and include deforestation leading to increased surface water flow, unscientific cultivation on hill slopes (like Jhum cultivation), and the excessive use of chemical fertilizers.

19. What are the different types of forest in Assam?
Answer:  Based on the document, the forests of Assam can be divided into five main types:

1. Tropical evergreen forest
2. Tropical semi-evergreen forest
3. Tropical moist deciduous forest
4. Riverine forest
5. Tropical dry deciduous forest

20. What is rain forest? Describe the characteristics of rain forest in Assam.
Answer: A rainforest is a type of forest that grows in areas with very high annual rainfall (300 cm or more). In Assam, these are called Tropical Evergreen Forests. They are characterized by:

1. Dense structure: They have three distinct layers of trees, from very tall trees to shorter ones.
2. Evergreen nature: The trees do not shed their leaves in any specific season.
3. Rich biodiversity: They are home to a wide variety of tall trees like Holong and Mekai, along with climbers, bamboos, canes, and orchids. These forests are found in the foothills near Arunachal Pradesh, parts of the Dibrugarh and Tinsukia districts, and the hilly areas of the Barak valley.

21. Write in brief about the importance and characteristics of riverine vegetation.
Answer: Riverine vegetation is a special type of forest that grows in the wet peripheries of rivers and wetlands. They are dominated by tall trees and grasses like Nal, Khagori, Tora, and cane.

Riverine forests provide suitable habitats for a variety of plants and animals. They are the primary environment for national parks like Kaziranga, Dibru-Saikhowa, and Orang. They are vital for maintaining the ecological balance of these riverine tracts.

22. State the location and land area of Kaziranga National Park.
Answer: Kaziranga National Park is located in the Golaghat, Nagaon, and Sonitpur districts of Assam. Its total land area is 858.98 km2.

23. Write the names and location of the national parks of Assam.
Answer: The national parks of Assam and their locations are:

1. Kaziranga National Park: Golaghat, Nagaon, and Sonitpur
2. Manas National Park: Chirang and Baksa
3. Orang National Park: Udalguri and Sonitpur
4. Nameri National Park: Sonitpur
5. Dibru-Saikhowa National Park: Dibrugarh and Tinsukia

24. Write how the wildlife sanctuaries maintain the ecological balance.
Answer: Wildlife sanctuaries maintain ecological balance by providing a protected environment for various plants and animals. They are safe from destructive human activities, which helps in the conservation of nature. By preserving the habitats of wild animals and diverse plant species, they help maintain the natural food chain and ensure the long-term survival of the state’s biodiversity.

25. Write about the changes in administrative boundaries in Assam during the post-independence period.
Answer: After India’s independence, Assam’s administrative boundaries underwent significant changes. In 1947, the Sylhet part of Assam was separated and joined East Pakistan (now Bangladesh). Later, three new states were carved out of Assam: Nagaland in 1963, Meghalaya in 1970, and Mizoram in 1971. The capital was also moved from Shillong to Dispur (Guwahati) in 1973. The state’s land area and geographical boundary have remained the same since 1971.

26. Write the names of the present districts of Assam and their headquarters.
Answer: As of 2025 Assam has 35 districts. Their names and headquarters are:

1. Baksa – Mushalpur
2. Barpeta – Barpeta
3. Biswanath – Biswanath Chariali
4. Bongaigaon – Bongaigaon
5. Cachar – Silchar
6. Charaideo – Sonari
7. Chirang – Kajalgaon
8. Darrang – Mangaldoi
9. Dhemaji – Dhemaji
10. Dhubri – Dhubri
11. Dibrugarh – Dibrugarh
12. Dima Hasao – Haflong
13. Goalpara – Goalpara
14. Golaghat – Golaghat
15. Hailakandi – Hailakandi
16. Hojai – Sankardev Nagar (Hojai)
17. Jorhat – Jorhat
18. Kamrup (Rural) – Amingaon
19. Kamrup (Metropolitan) – Guwahati
20. Karbi Anglong – Diphu
21. Karimganj – Karimganj
22. Kokrajhar – Kokrajhar
23. Lakhimpur – North Lakhimpur
24. Majuli – Garamur
25. Morigaon – Morigaon
26. Nagaon – Nagaon
27. Nalbari – Nalbari
28. Sivasagar – Sivasagar
29. Sonitpur – Tezpur
30. South Salmara–Mankachar – Hatsingimari
31. Tamulpur – Tamulpur
32. Tinsukia – Tinsukia
33. Udalguri – Udalguri
34. West Karbi Anglong – Hamren
35. Majuli – Garamur

27. What is the land area of Assam? Where is the state’s capital located? Write the names of the largest and smallest districts of Assam in respect of land area.
Answer:

1. Land area of Assam: 78,438 km2.
2. State’s capital: Dispur (Guwahati).
3. Largest and smallest districts (prior to 2015):

   • Largest: Karbi Anglong (10,434 km2)

   • Smallest: Kamrup Metropolitan (955 km2)

28. What is the population of Assam according to 2011 Census? Write the names of the largest and smallest districts of Assam in terms of population size.
Answer: Population of Assam (2011 Census): 3,12,05,576

Largest and smallest districts (2011 Census):

• • Largest: Nagaon (2.82 million)

  • Smallest: Dima-Hasao (2.14 lakh)

29. Write Short Notes:

(a) Assam and Monsoon Climate
Answer: Assam falls under the subtropical monsoon climate, which is dominated by the monsoon winds. The South-west monsoon brings heavy rainfall in the summer, which is vital for the state’s agriculture. The North-east monsoon, which blows in winter, is generally dry but can cause some rainfall. The monsoons are responsible for the distinct wet and dry seasons and are a key factor in Assam’s climate.

(b) South-West Monsoon Wind
Answer: The South-West Monsoon wind blows during the summer season. It enters India from the Arabian Sea and the Bay of Bengal, carrying a huge amount of moisture. This wind is the primary reason for the heavy rainfall in Assam and the North-Eastern region. It is a warm and moist wind that is obstructed by the hills and mountain ranges, causing orographic rainfall.

(c) North-East Monsoon Wind
Answer: The North-East Monsoon wind blows during the winter season. It is a dry and cold wind that originates from Central Asia. It does not generally cause rainfall in Assam, but sometimes it absorbs moisture from the Brahmaputra river and gives some amount of rainfall in the southwestern part of the state.

(d) Summer Season of Assam
Answer: The summer season in Assam is characterized by two parts: the Pre-Monsoon season (March-May) and the Monsoon season (June-September). During the pre-monsoon, temperatures increase, and thunderstorms with rain and lightning occur. The monsoon brings moderate to heavy rainfall, leading to floods. The summer season is hot, humid, and very wet.

(e) Pre-Monsoon Season of Assam
Answer: The pre-monsoon season in Assam is from early March to the end of May. It is a transitional period where the temperature slowly rises. The weather is often pleasant in the morning but can be very hot in the afternoon. This season is known for sudden rainfall with thunder and lightning, which is locally called Bordoichilla. This rain is important for the cultivation of paddy, tea, and jute.

(f) Spatial Distribution of Rainfall in Assam
Answer: The spatial distribution of rainfall in Assam is not uniform. Rainfall is generally high in the hills and foothill areas, and in districts like Tinsukia, Dibrugarh, and Kokrajhar. In central Assam, districts like Nagaon and Karbi Anglong receive comparatively less rainfall. This uneven distribution is due to the state’s topography and the way it interacts with the monsoon winds.

(g) Administrative Divisions of Assam
Answer: For administrative convenience, the state of Assam is divided into districts. As of the information provided in the document, there are 33 districts. The administrative boundaries have changed over time, with new states like Nagaland, Meghalaya, and Mizoram being carved out of Assam. The state’s capital is in Dispur (Guwahati).

(h) District Level Population of Assam
Answer: The population of Assam is not uniformly distributed at the district level. According to the 2011 Census, Nagaon district is the most populous, while Dima-Hasao is the least populous. Population density is generally higher in the fertile plains and lower in the hilly or arid regions.

(i) BTAD
Answer: BTAD stands for Bodoland Territorial Area Districts. It was formed in 2003 to fulfill the hopes and aspirations of the Bodo tribal groups. Four districts—Kokrajhar, Chirang, Baksa, and Udalguri—fall under this administrative division.