Geography of Bihar: BPSC Notes

Every year, lakhs of aspirants prepare for the state service exams or the UPSC Civil Service Exams. The Bihar Public Service Commission Combined Competitive Exam (CCC Exam) is the common entry point for about 20 prestigious posts in the Bihar administration. The Bihar Public Service Commission (BPSC) conducts recruitment exams to fill up Group A, B and C vacancies in the Bihar state administration. 

Similar to the IAS exam which is conducted by the Union Public Service Commission (UPSC), the BPSC exam comprises three stages:

• Stage 1 – Prelims
• Stage 2 – Mains
• Stage 3 – Interview

Therefore, aspirants who want to take the BPSC exam should strategise their BPSC preparation in coordination with the UPSC IAS Exam preparation. The main difference between preparing for the BPCS exam and the UPSC exam is that in the latter, applicants must acquire particular about the state of Bihar, including its history, geography, politics and current affairs.

Learn about the BPSC Exam in detail, by visiting the linked article.

In this article, the Geography of Bihar is discussed in detail, in order to help aspirants prepare for the BPCS exam. 

BPSC Notes- Geography Of Bihar-Download PDF Here

About Bihar

Bihar is located in the eastern region of India. It is a landlocked state that shares borders with West Bengal, Uttar Pradesh and Jharkhand in India. Bihar borders West Bengal in the south, Jharkhand in the south, Uttar Pradesh in the west, and Nepal in the north. With a 94,163 sq km area, it is the twelfth-largest state in terms of both territory and population. Additionally, Bihar is the fourth-most populous state in India. Some facts about the state are given below:

All aspirants studying for any Bihar government exam should be familiar with Bihar geography. Important rivers, the climate, the soil, the land area, etc. are all part of Bihar’s geography. We have provided detailed information on Bihar’s geography in the article given below, which will be helpful for the BPSC exam.

Aspirants preparing for the BPSC Exam must visit the following articles to know the exam details:

Physiography of Bihar: Location and Geological Structure

Location: 

• The eastern state of Bihar is located between latitudes 24°20’10″N and 27°31’15″N and longitudes 83°19’50″E and 88°17’40″E. 
• In a subtropical area of the temperate zone, the state of Bihar is fully landlocked. 
• Bihar occupies a transitional position in terms of climate, economy, and culture because it is situated between the humid West Bengal in the east and the slightly less humid Uttar Pradesh in the west. It is bordered by Jharkhand in the south and Nepal in the north. 
• The Ganges River cuts across the centre of the Bihar Plain, dividing it into two unequal parts (North Bihar and South Bihar). 
• The terrain in Bihar is generally 173 feet above sea level.
• Bihar has boundaries with the states of 
  • Uttar Pradesh, Jharkhand and 
  • West Bengal. 
• The state also shares a border with Nepal in the north. The length of Nepal border – 601 km
• There are seven districts that border Nepal in the west to the east direction:
  • West Champaran, 
  • East Champaran, 
  • Sitamarhi, Madhubani, 
  • Supaul, Araria, and 
  • Kishanganj
• A total of seven districts share the border with UP in the north to south direction 
  • West Champaran, 
  • Gopalganj, 
  • Siwan, 
  • Saran, 
  • Bhojpur, 
  • Buxar and 
  • Kaimur
• There are eight districts which border Jharkhand in the west to east direction
  • Rohtas, 
  • Aurangabad, 
  • Gaya, Nawada, 
  • Jamui, Banka, 
  • Bhagalpur and
  • Katihar

• Three districts border West Bengal in the north to south direction
  • Kishanganj, 
  • Purnia and 
  • Katihar

• Rivers which forms boundaries with Uttar Pradesh in some parts:
  • Ganga, 
  • Ghaghara and
  • Gandak 
• Sone river forms a boundary with Jharkhand in Rohtas district

Landforms:

On basis of physical and structural conditions Bihar has been divided into three parts: 

• The Southern Plateau Region
• Bihar’s Gangetic Plain
• The Shivalik Region

The rocks to the north are younger, while rocks of the south are relatively older rocks. The north-west is the Terai region, the Central region is the Gangetic plain and south is the Plateau region. The Bihar plain is the youngest to be formed. Each of the divisions are discussed in detailed in the following paragraphs:

Shivalik Region: 

• The state of West Champaran is shadowed by the area in the sub-Himalayan foothills of the Shivalik range spanning an area that is 32 km long and 6-8 km wide. 
• There is a band of moist deciduous woodland covering the West Champaran district. This includes reeds, grass, and scrub in addition to trees.

Bihar’s Gangetic Plain: 

• The Southern Plateau and the Northern Mountains are separated by Bihar’s Plain. The 150-meter contour line forms its northern and southern boundaries. 
• The Ganges River divides the huge, rich Bihar Plain into two unequal regions known as North Bihar and South Bihar. 
• The Northern Bihar Plain is located in the plains of Samastipur, Begusarai, Saharsa, and Katihar, as well as East Champaran and West Champaran (Terai areas with higher elevation). 
• Saryu, Gandak, Burhi Gandak, Bagmati, Kamla-Balan, Kosi, and Mahananda, along with their tributaries, drain the region. 
• Due to the numerous hills in this area, including the hills of Gaya, Rajgir, Giriyak, Bihar Sharif, Sheikhpura, Jamalpur, and Kharagpur, the southern Bihar Plain is narrower than the northern Plain of Bihar and triangular in shape.

Southern Plateau Region: 

• The area is situated between Banka in the East and the Kaimur district in the West. 
• Hard rocks like gneiss, schist, and granite make up its structure. 
• This area is home to numerous conical hills formed of batholim, including Pretshil, Ramshila, and Jethian Hill.

Aspirants preparing for the competitive exams can read more about the major Landorms of Earth, in the linked article.

Related Links:

Geological Structure of Bihar:

With the oldest formation, the Dharwar Rock System, located in the southern portion of the state, bordering Jharkhand, and the youngest formation, the Quaternary Rock System, located in the central part of the state, Bihar has an unified framework of its geological formations (in between Dharwar System and Tertiary rock system of North-Western Terai Region of Bihar).

A four-part division of Bihar’s geological structure is as follows:

• Dharwar Rock System
• Vindhyan Rock System
• Tertiary Rock System
• Quaternary Rock System

Given below is the detailed information about each of the rock system of Bihar:

• Dharwar Rock System:

• • • The Dharwar Rock Formation is a part of the oldest Archaean Rock System, which dates back between 3100 and 2100 million years (3.1-2.1 Arab years ago).
    • This Dharwar Rock System created the southern regions of the Bihar districts of Aurangabad, Gaya, Nawada, Jamui, and Munger.
    • Quartzite, Phyllite, Gneiss, Schist, Shale, and Slate made up this rock system. Schist and mica are abundant in the area.
    • Its name comes from the abundantly populated Dharwar district of Karnataka.

• Vindhyan Rock System:

• • • Vindhyan Rocks may be found in Rohtas District’s Son Valley and Kaimur District’s Son Valley.
    • This is part of the Purana Rock System, which formed between 130 and 600 million years ago (1.3-0.6 Arab years ago). 
    • The Vindhyan Ranges served as the basis for the naming of this rock formation. 
    • Sandstone, limestone, dolomite, quartzite, and shale are the main constituents of Vindhyan rocks.
    • Large reserves of limestone and pyrite are present, both of which are used commercially.

• Tertiary Rock System:

• • • In the course of the Himalayan Ranges’ formation, this rock system was developed. 
    • They are found in the Himalayan Terai region of Bihar and were created 60 to 70 million years ago.
    • The Tertiary Rock System of Bihar can be found in the Western Champaran districts in the state’s Upper North-Western regions or in the Terai Region of the Shivalik Ranges.
    • These are the result of sediments in the Tethys Sea being warped downward by the tectonic movements of the Indian and Eurasian plates.
    • Sandstone, sandy shale, mudstone, and conglomerate make up this rock system.

• Quaternary Rock System:

• • It is situated between the northern Chhotanagpur plateau region and the southern Himalayan Terai region of Bihar.
  • The formation of this rock system began in the last million (10 lakh) years during the Pleistocene, and it is still continuing on today.
  • This rock structure was created by the rapid deposition of alluvium by Himalayan and Peninsular rivers like the Ganga, Ghaghra, Gandak, Koshi, Bagmati, Koshi, Son, Mahananda, and Punpun, which slowly deposited and crushed to create the Quaternary rocks.
  • Sandstone, conglomerate, coarse gravels, and other materials are used to make quaternary rocks.

Candidates can check the exam dates as released by the Bihar Public Service Commission by visiting the BPSC Calendar, in the linked article. We also have compiled Geography questions that will be helpful for BPSC candidates as well. Check them below:

• UPSC Prelims Geography Questions
• UPSC Mains Geography Questions
• 100+ Daily Geography Questions for IAS Preparation

Political Geography of Bihar

The state is organised into 9 divisions, 38 districts, 101 subdivisions and 534 circles. For administrative purposes, there are 12 municipal corporations, 49 Nagar Parishads and 80 Nagar Panchayats.

For other PSC Exam notifications, check the linked articles mentioned in the table below:

Climate of Bihar

• Bihar has a humid subtropical climate and is entirely located in the Subtropical section of the Temperate Zone. Generally speaking, it has a subtropical climate, with hot summers and freezing winters. 
• Although there are very few tropical and humid months, the climate is fairly warm. 
• The climate of Bihar shows a transition between humid to sub-humid or dry climate. Basically, the Eastern part of Bihar is more or less humid in nature and the Western part of Bihar is sub-humid or dry in nature.
• Many months of the year are warm to hot with temperatures that are consistently above 25°C, occasionally reaching 29°C. 
• The optimum travel season is from October to April because there is less rain during that time.

Some facts important for the exam are given below:

Factors influencing the climate of Bihar:

The climate of Bihar is influenced mainly by following five factors: 

• Proximity to Himalayas.
• Proximity to Tropic of Cancer.
• Proximity to Bay of Bengal.
• Activities of South-West monsoon.
• Nor-westers and Summer Winds.

Seasons in Bihar

Bihar experiences three distinct seasons because it is located in a tropical area:

• Summer Season: March to June
• Rainy Season: July to October
• Winter Season: November to February

Summer Season: 

• It begins in March with the Inter Tropical Convergence zone moving slowly and gradually towards the Tropic of Cancer and extends up to Ganga Plains. 
• It causes the air pressure to drop and the temperature to rise in the area. Bihar experiences the greatest temperatures, which can reach up to 45 °C, particularly in Gaya, the state’s hottest region.
• In the Bihar plains, a strong summer wind known as “Loo” blows in the months of April, May, and early June. There are many health conditions and even deaths in Bihar as a result of the dry, hot air.
• Nearly every week in the afternoon and evening in the months of April and May, Bihar encounters thunderstorms (carrying dust and high wind) that frequently result in light rain but occasionally also include hailstorms that seriously harm Rabi Crops, particularly wheat.

Rainy Season:

• Nearly 91% of Bihar’s yearly rainfall falls during the rainy season, and that too in just three months: June, July, and August.
• The Inter Tropical Convergence Zone (ITCZ), which draws the South-West monsoon from the Arabian Ocean and Bay of Bengal, completely shifts over the Ganga Plain in the middle of June. 
• Bihar receives monsoon from both of the monsoon’s branches: 
  • S-W Monsoon branch in the Bay of Bengal.
  • S-W Monsoon’s Arabian Ocean Branch.
• In Bihar, paddy cultivation takes place during the rainy season, which is heavily dependent on the monsoon. 
• The Northern Part of Bihar experiences good rainfall virtually every year, and almost every year floods occur due to excess water released by Nepal through several streams rather than heavy rain (especially Koshi river). Each year, floods in Northern Bihar result in significant losses.
• However, the monsoon in Bihar, particularly in the south, is exceedingly irregular, and droughts here almost always happen every two to three years. 
• In addition to floods and drought, Bihar faces a large number of diseases during the rainy season, including malaria, typhoid, dengue, and others. The amount of rainfall received by Bihar in the rainy season is given below:

Retreating Monsoon:

• The S-W Monsoon slows down and begin to retreat after August.
• It is accompanied by little to no rain. 
• Monsoon retreat comes to a close in early November. Little rain due to the Monsoon’s retreat throughout the months of September, October, and early November slowly ushers in the winter season in the state.
• The average temperature drops from 34° Celsius in July and August to (25° Celsius to 30° Celsius) by the end of October.

Winter Season:

• After the summer and rainy season ends, there is a decreased heating of the land surface. The fall in temperature marks the beginning of the winter season.
• The day length significantly shortens, and the nights are chilly and long. 
• The temperature often drops the most in December and January. 
• From 19.4° to 22.2° Celsius in November to 10.5° to 7° Celsius in January, the temperature drops.
• The Shiwalik Ranges in North-Western Bihar experience frost in January, which significantly damages agriculture in the area (especially Potato).
• Light rain (approximately 5% to 10% of the year’s total rainfall) is brought on by North-Western Disturbances in the months of January and February, which aids in the growth of Rabi Crops.

Learn about the Climate of India in detail, in the linked article. 

The agro-climatic zones of Bihar are given below:

• Rainfall in the 13 districts that make up the North-West zone ranges from 1040 to 1450 mm annually.
• With an average yearly rainfall of 1200 to 1700 millimetres and loam or clay-loam soil, the north-east zone includes 8 districts.
• Rainfall in the South Zone ranges from 990 to 1300 mm, with 17 districts covered and soil types including sandy loam, loamy, clayey, and clay-loam.

Important Rivers of Bihar

Bihar’s economy is heavily dependent on rivers because the state is dominated by agriculture. There are numerous perennial and seasonal rivers in Bihar. In Bihar, these rivers provide the majority of the surface water. Bihar’s alluvial plains, both in the north and in some areas of the south, always have water available. Bihar is split into two unequal portions by the Ganga river. As a result, the rivers of Bihar have been divided into two main groups: rivers in North Bihar and rivers in South Bihar.

• Rivers in North Bihar: North Bihar Plains are an alluvial plain in Bihar that is located north of the Ganga river. Numerous rivers, some of which are seasonal and perennial, flow through these plains. Some of the most significant rivers in north Bihar are :

• Ghaghra, 

• Gandak, 

• Burhi Gandak, 

• Bagmati, 

• Kosi, 

• Kamla and 

• Mahananda. 

All of these rivers drain into the Ganges. On the other hand, through the Kosi river, the Bagmati-Adhwara, Kamla-Balan, etc. fall into the Ganga river. Some important characteristics of these rivers are as follows:

• The main rivers in northern Bihar originate in the Himalayas.
• A sizable percentage of their catchment is located in the glacial area.
• These rivers, which originate in the Himalayas, are situated between Nepal and Tibet.
• These rivers receive an abundance of precipitation during the monsoon season that is 80 to 90 times greater than the dry season.
• Additionally, these rivers create chaurs (Ox-bow lakes) as they change their route.
• A few of the rivers in this area, including the Gandak, Burhi Gandak, and Ghagra, are rather stable.
• The Baghmati, Adhawra Group, Kamla-Balan, and Kosi rivers in northern Bihar, on the other hand, continue to be very unstable.

• Rivers in South Bihar: The major rivers in south Bihar are:

• Karmnasa

• Sone

• Punpun

• Kiul

• Badua Chandan

• These rivers flow into the Ganga and are primarily responsible for draining the south region of Bihar. Some of the characteristics of the river in southern Bihar are:

• • The Vindhyanchal hills or the hills of Chhotanagpur and Rajmahal are where the rivers of southern Bihar originate.
  • The drainage of the area is impeded by the Ganga’s leeve-like southern bank.
  • Additionally, the Tal formation, a low-lying area created by the paths of multiple rivers, is a distinguishing feature of Bihar’s southern plains.
  • Fatuha Tal, Bakhtiyarpur Tal, Barh Tal, More Tal, Mokama Tal, Barahiya Tal, Singhaul Tal are the tals formed by these rivers. 
  • The soils of tal areas and their vicinity are medium to heavy textured and slightly to moderately alkaline.

The Ganga River spans 445 kilometres in Bihar. Additionally, it has a 5473 sq km catchment area. The other three significant rivers in terms of catchment area are the Kosi (74,030 sq km), Sone (70,228 sq km), and Gandak river (40553 sq km). All the necessary information about the important rivers of Bihar are covered below:

Waterfalls and Hot Springs of Bihar:

Some of the mains waterfalls and hotsprings of the state of Bihar are:

Learn about the Major River Systems in India, in the linked article.

Flora and Fauna of Bihar

One of India’s most biodiverse states is Bihar. Bihar boasts a diverse range of flora and fauna (plants and animals, respectively). Bihar has 3 national parks and 21 animal sanctuaries. Around 800 sq km of land is covered by the Valmiki National Park, which is located in Bihar’s West Champaran region, close to Nepal. Shorea robusta, a damp sal-bearing forest, makes up the majority of the park. Some important fact about the flora and fauna of the state from the exams point of view are given below:

• Total forest area – 7299 sq. km which is 7.75% of total area (1.04% of India’s forest).
• Minimum forest area – Sheikhpura
• Maximum forest area – Kaimur district
• The total area under very dense forest is in West Champaran
• The Dry Deciduous forest is most abundant in Bihar, Kaimur, Purnia, Raxaul etc.
• The Moist Deciduous forest is found in Kishanganj, West Champaran, Kaimur, Gaya etc.

The important National Parks, Wildlife Sanctuaries and Tiger Reserves in the state of Bihar are :

Candidates can read about other important Geography topics in the articles linked below:

Soil in Bihar

In Bihar, which is a state with a large agricultural sector, agriculture is the main source of income. The soils in Bihar are separated into North Bihar Plains and South Bihar Plains based on their composition, regional distribution, and physical characteristics.

• Soils of North Bihar

• • • Piedmont Swamp Soil
    • Terai Soil
    • Recent Alluvium Soil- Khadar and Bhangar

• Soils of South Bihar

• • Old Alluvium Soil
  • Tal Soil
  • Balthar Soil
  • Red Sandy Soil

Different types of soil found in Bihar are given below with some important feature of these:

Candidates are advised to visit Classification of Soil in India – Types of Soil in India, to learn about types of soil in India.

Candidates should go through the links given below to understand and compare the IAS Exam and the BPSC Exam: