Here is a detailed explanation of the topic “Natural Disaster in Bihar” for BPSC Prelims, covering:
Geography-9
- Floods in North Bihar
- Drought-Prone Areas in South Bihar
- Water Resource Management Projects
Environmental and Geographical Challenges in Bihar: Natural Disaster
Bihar faces dual water crises: recurring floods in the north and frequent droughts in the south. These issues are compounded by poor infrastructure, climate variability, and human-induced changes in land and river systems.
1. Floods in North Bihar
Regions Affected:
- North of Ganga River, including districts:
- Supaul, Saharsa, Madhepura, Darbhanga, Muzaffarpur, Sitamarhi, Khagaria, Purnia, Araria, Katihar, West Champaran
Major Flood-Prone Rivers:
- Kosi (called the “Sorrow of Bihar”)
- Gandak
- Bagmati
- Kamla-Balan
- Burhi Gandak
- Mahananda
Causes of Floods:
| Natural Causes | Man-made Causes |
| Intense rainfall in Himalayas (Nepal) | Encroachment of riverbeds and wetlands |
| Rivers carry high silt load and change course frequently | Poor maintenance of embankments and canals |
| Flat terrain with low drainage slope | Unplanned construction and population pressure |
| Backflow due to rising Ganga levels during monsoon | Deforestation in catchment areas (Nepal-Bihar border) |
Impact of Floods:
- Massive crop damage and soil erosion
- Displacement and humanitarian crisis
- Outbreaks of waterborne diseases
- Damage to roads, rail, and public infrastructure
2. Drought-Prone Areas in South Bihar
Regions Affected:
- South of Ganga River, especially:
- Gaya, Aurangabad, Nawada, Rohtas, Nalanda, Jamui, Banka
Causes of Drought:
| Factor | Details |
| Low and erratic rainfall | Average < 1,000 mm in some areas |
| Rainfed agriculture | Heavy reliance on monsoon |
| Deforestation and land degradation | Plateau areas with thin soil |
| Limited irrigation | Poor coverage of canals and groundwater extraction |
| Over-dependence on tube wells | Groundwater depletion in summer |
Impact of Drought:
- Crop failure and loss of rural income
- Migration of laborers to urban areas
- Depletion of groundwater
- Drinking water scarcity in summer
3. Water Resource Management Projects
To address floods and droughts, Bihar has initiated large-scale water management projects, both independently and in collaboration with the Centre.
Major Flood Control Projects:
| Project | River | Area Benefited | Key Features |
| Kosi Project | Kosi | Supaul, Saharsa, Madhepura | Barrage at Hanuman Nagar (Nepal), embankments, canals |
| Gandak Project | Gandak | Gopalganj, Muzaffarpur, East Champaran | Canal irrigation and flood protection |
| Bagmati Project | Bagmati | Sitamarhi, Muzaffarpur | Embankments and flood control works |
| Sluice Gates & Embankments | Burhi Gandak, Kamla-Balan | North Bihar | Reinforced concrete structures to regulate flow |
Irrigation and Drought Management Projects:
| Project | Purpose | Area |
| Sone Canal System | Irrigation from Sone River | South Bihar: Rohtas, Aurangabad |
| Koshi-Mechi Interlink Project | Interlink rivers to divert excess water | Koshi and Mechi basins (SE Bihar) |
| Ganga Water Supply Scheme | Drinking & irrigation water from Ganga to South Bihar | Nalanda, Gaya, Nawada |
| Har Khet Ko Pani (PMKSY) | Irrigation for every farm | Statewide |
| Nal Jal Yojana | Rural drinking water via pipelines | Statewide (especially drought-prone areas) |
Summary Table: Environmental Challenges of Bihar
| Issue | Region | Causes | Rivers Involved | Government Action |
| Floods | North Bihar | Himalayan rainfall, siltation, embankment breach | Kosi, Gandak, Bagmati | Kosi Project, embankments |
| Droughts | South Bihar | Rainfall deficit, poor irrigation | Sone, Punpun | Canal networks, PMKSY |
| Water Mismanagement | Statewide | Inefficient infrastructure | Ganga and tributaries | Jal Jeevan Mission, AMRUT |
Likely MCQs
| Question | Answer |
| “Sorrow of Bihar” | Kosi River |
| Most flood-prone districts | Supaul, Darbhanga, Khagaria |
| Drought-prone districts | Gaya, Aurangabad |
| River with major irrigation canal in south Bihar | Sone River |
| Project linking Kosi and Mechi rivers | Koshi-Mechi Interlink Project |
Complete Geography Notes on Environmental and Geological Challenges in Bihar for PSC and Other Competitive Exams in 2025
Geography-9
Here is a detailed explanation of the topic “Environmental and Geographical Challenges in Bihar” for BPSC Prelims, covering:
- Floods in North Bihar
- Drought-Prone Areas in South Bihar
- Water Resource Management Projects
Environmental and Geographical Challenges in Bihar
Bihar faces dual water crises: recurring floods in the north and frequent droughts in the south. These issues are compounded by poor infrastructure, climate variability, and human-induced changes in land and river systems.
1. Floods in North Bihar
Regions Affected:
- North of Ganga River, including districts:
- Supaul, Saharsa, Madhepura, Darbhanga, Muzaffarpur, Sitamarhi, Khagaria, Purnia, Araria, Katihar, West Champaran
Major Flood-Prone Rivers:
- Kosi (called the “Sorrow of Bihar”)
- Gandak
- Bagmati
- Kamla-Balan
- Burhi Gandak
- Mahananda
Causes of Floods:
| Natural Causes | Man-made Causes |
| Intense rainfall in Himalayas (Nepal) | Encroachment of riverbeds and wetlands |
| Rivers carry high silt load and change course frequently | Poor maintenance of embankments and canals |
| Flat terrain with low drainage slope | Unplanned construction and population pressure |
| Backflow due to rising Ganga levels during monsoon | Deforestation in catchment areas (Nepal-Bihar border) |
Impact of Floods:
- Massive crop damage and soil erosion
- Displacement and humanitarian crisis
- Outbreaks of waterborne diseases
- Damage to roads, rail, and public infrastructure
2. Drought-Prone Areas in South Bihar
Regions Affected:
- South of Ganga River, especially:
- Gaya, Aurangabad, Nawada, Rohtas, Nalanda, Jamui, Banka
Causes of Drought:
| Factor | Details |
| Low and erratic rainfall | Average < 1,000 mm in some areas |
| Rainfed agriculture | Heavy reliance on monsoon |
| Deforestation and land degradation | Plateau areas with thin soil |
| Limited irrigation | Poor coverage of canals and groundwater extraction |
| Over-dependence on tube wells | Groundwater depletion in summer |
Impact of Drought:
- Crop failure and loss of rural income
- Migration of laborers to urban areas
- Depletion of groundwater
- Drinking water scarcity in summer
3. Water Resource Management Projects
To address floods and droughts, Bihar has initiated large-scale water management projects, both independently and in collaboration with the Centre.
Major Flood Control Projects:
| Project | River | Area Benefited | Key Features |
| Kosi Project | Kosi | Supaul, Saharsa, Madhepura | Barrage at Hanuman Nagar (Nepal), embankments, canals |
| Gandak Project | Gandak | Gopalganj, Muzaffarpur, East Champaran | Canal irrigation and flood protection |
| Bagmati Project | Bagmati | Sitamarhi, Muzaffarpur | Embankments and flood control works |
| Sluice Gates & Embankments | Burhi Gandak, Kamla-Balan | North Bihar | Reinforced concrete structures to regulate flow |
Irrigation and Drought Management Projects:
| Project | Purpose | Area |
| Sone Canal System | Irrigation from Sone River | South Bihar: Rohtas, Aurangabad |
| Koshi-Mechi Interlink Project | Interlink rivers to divert excess water | Koshi and Mechi basins (SE Bihar) |
| Ganga Water Supply Scheme | Drinking & irrigation water from Ganga to South Bihar | Nalanda, Gaya, Nawada |
| Har Khet Ko Pani (PMKSY) | Irrigation for every farm | Statewide |
| Nal Jal Yojana | Rural drinking water via pipelines | Statewide (especially drought-prone areas) |
Summary Table: Environmental Challenges of Bihar
| Issue | Region | Causes | Rivers Involved | Government Action |
| Floods | North Bihar | Himalayan rainfall, siltation, embankment breach | Kosi, Gandak, Bagmati | Kosi Project, embankments |
| Droughts | South Bihar | Rainfall deficit, poor irrigation | Sone, Punpun | Canal networks, PMKSY |
| Water Mismanagement | Statewide | Inefficient infrastructure | Ganga and tributaries | Jal Jeevan Mission, AMRUT |
Likely MCQs
| Question | Answer |
| “Sorrow of Bihar” | Kosi River |
| Most flood-prone districts | Supaul, Darbhanga, Khagaria |
| Drought-prone districts | Gaya, Aurangabad |
| River with major irrigation canal in south Bihar | Sone River |
| Project linking Kosi and Mechi rivers | Koshi-Mechi Interlink Project |
Geography-9
Here is a detailed explanation of the topic “Environmental and Geographical Challenges in Bihar” for BPSC Prelims, covering:
- Floods in North Bihar
- Drought-Prone Areas in South Bihar
- Water Resource Management Projects
Environmental and Geographical Challenges in Bihar
Bihar faces dual water crises: recurring floods in the north and frequent droughts in the south. These issues are compounded by poor infrastructure, climate variability, and human-induced changes in land and river systems.
1. Floods in North Bihar
Regions Affected:
- North of Ganga River, including districts:
- Supaul, Saharsa, Madhepura, Darbhanga, Muzaffarpur, Sitamarhi, Khagaria, Purnia, Araria, Katihar, West Champaran
Major Flood-Prone Rivers:
- Kosi (called the “Sorrow of Bihar”)
- Gandak
- Bagmati
- Kamla-Balan
- Burhi Gandak
- Mahananda
Causes of Floods:
| Natural Causes | Man-made Causes |
| Intense rainfall in Himalayas (Nepal) | Encroachment of riverbeds and wetlands |
| Rivers carry high silt load and change course frequently | Poor maintenance of embankments and canals |
| Flat terrain with low drainage slope | Unplanned construction and population pressure |
| Backflow due to rising Ganga levels during monsoon | Deforestation in catchment areas (Nepal-Bihar border) |
Impact of Floods:
- Massive crop damage and soil erosion
- Displacement and humanitarian crisis
- Outbreaks of waterborne diseases
- Damage to roads, rail, and public infrastructure
2. Drought-Prone Areas in South Bihar
Regions Affected:
- South of Ganga River, especially:
- Gaya, Aurangabad, Nawada, Rohtas, Nalanda, Jamui, Banka
Causes of Drought:
| Factor | Details |
| Low and erratic rainfall | Average < 1,000 mm in some areas |
| Rainfed agriculture | Heavy reliance on monsoon |
| Deforestation and land degradation | Plateau areas with thin soil |
| Limited irrigation | Poor coverage of canals and groundwater extraction |
| Over-dependence on tube wells | Groundwater depletion in summer |
Impact of Drought:
- Crop failure and loss of rural income
- Migration of laborers to urban areas
- Depletion of groundwater
- Drinking water scarcity in summer
3. Water Resource Management Projects
To address floods and droughts, Bihar has initiated large-scale water management projects, both independently and in collaboration with the Centre.
Major Flood Control Projects:
| Project | River | Area Benefited | Key Features |
| Kosi Project | Kosi | Supaul, Saharsa, Madhepura | Barrage at Hanuman Nagar (Nepal), embankments, canals |
| Gandak Project | Gandak | Gopalganj, Muzaffarpur, East Champaran | Canal irrigation and flood protection |
| Bagmati Project | Bagmati | Sitamarhi, Muzaffarpur | Embankments and flood control works |
| Sluice Gates & Embankments | Burhi Gandak, Kamla-Balan | North Bihar | Reinforced concrete structures to regulate flow |
Irrigation and Drought Management Projects:
| Project | Purpose | Area |
| Sone Canal System | Irrigation from Sone River | South Bihar: Rohtas, Aurangabad |
| Koshi-Mechi Interlink Project | Interlink rivers to divert excess water | Koshi and Mechi basins (SE Bihar) |
| Ganga Water Supply Scheme | Drinking & irrigation water from Ganga to South Bihar | Nalanda, Gaya, Nawada |
| Har Khet Ko Pani (PMKSY) | Irrigation for every farm | Statewide |
| Nal Jal Yojana | Rural drinking water via pipelines | Statewide (especially drought-prone areas) |
Summary Table: Environmental Challenges of Bihar
| Issue | Region | Causes | Rivers Involved | Government Action |
| Floods | North Bihar | Himalayan rainfall, siltation, embankment breach | Kosi, Gandak, Bagmati | Kosi Project, embankments |
| Droughts | South Bihar | Rainfall deficit, poor irrigation | Sone, Punpun | Canal networks, PMKSY |
| Water Mismanagement | Statewide | Inefficient infrastructure | Ganga and tributaries | Jal Jeevan Mission, AMRUT |
Likely MCQs
| Question | Answer |
| “Sorrow of Bihar” | Kosi River |
| Most flood-prone districts | Supaul, Darbhanga, Khagaria |
| Drought-prone districts | Gaya, Aurangabad |
| River with major irrigation canal in south Bihar | Sone River |
| Project linking Kosi and Mechi rivers | Koshi-Mechi Interlink Project |
