FLOODS IN INDIA

FLOODS IN INDIA

Floods are defined as a high-water level that overflows natural banks along a stream or river. Flood-prone areas in India are divided into four regions:

1. The Brahmaputra River Region: Includes Assam, Arunachal Pradesh, Meghalaya, Mizoram, Manipur, Tripura, Nagaland, Sikkim, and parts of West Bengal.
2. The Ganga River Region: Covers Uttarakhand, Uttar Pradesh, Bihar, Jharkhand, parts of West Bengal, Punjab, Haryana, Himachal Pradesh, Rajasthan, Madhya Pradesh, and Delhi.
3. The North-West River Region: Includes Jammu and Kashmir, Punjab, Himachal Pradesh, Haryana, and Rajasthan.
4. The Central India and Deccan Region: Covers Andhra Pradesh, Karnataka, Tamil Nadu, Kerala, Orissa, Maharashtra, Gujarat, and parts of Madhya Pradesh.

Causes of Floods in India

1. Natural Causes

• Heavy rainfall: Concentrated rainfall leads to rivers overflowing due to excess surface runoff.
• Cloud bursts: These are heavy thunderstorms resulting in more than 50 mm of rain in a short period, causing damage and flooding.
• Sediment deposition: River beds become shallow due to sedimentation, reducing the capacity of rivers and causing them to overflow.
• Cyclones: Cyclone-generated sea waves cause coastal flooding, such as the 1994 Orissa cyclone that led to severe floods.
• Change in river course: Meandering rivers or changes in their course can cause sudden floods.
• Tsunami: Large-scale coastal areas can be flooded by tsunamis that bring seawater inland.
• Lack of lakes: Lakes that store excess water regulate flow, but their reduction limits this ability.
• Heavy melting of ice and snow: This leads to a rise in water levels, contributing to floods.
• Transgression of the sea: During tropical cyclones, sea water advances inland, causing floods.

2. Anthropogenic (Human-made) Causes

• Increased urbanization: Urban sprawl has led to impermeable surfaces, reducing water absorption and increasing runoff.
• Deforestation: The removal of trees allows faster water flow, reducing the land’s ability to retain water and leading to floods.
• Interference in drainage systems: Poor planning in the construction of infrastructure like bridges and roads causes drainage congestion.
• International dimension: Rivers originating in neighboring countries such as China, Nepal, and Bhutan can contribute to floods in India.
• Population pressure: Large populations increase the demand for resources, aggravating deforestation, soil erosion, and overgrazing.
• Poor water and sewage management: Old systems in urban areas collapse during heavy rains, causing urban flooding.
• Unscientific land use: Improper farming practices, such as leaving fields bare, can result in soil erosion and floods.

Impacts of Floods in India

1. Social Impacts

• Loss of lives: Between 1980 and 2017, India experienced 235 major floods, resulting in 126,286 deaths and affecting 1.93 billion people.

• Risk of violence: Vulnerable groups, especially women, face increased risks of violence during floods.
• Affect habitation: Flooding leads to the destruction of habitats, loss of land, and displacement of families and animals.
  • Example: Since 1947, in Assam, more than 1.25 lakh families have lost either agricultural or residential land due to floods.
• Affect essential services: Disruption of railways, road communication, and vital services hampers movement and delivery of goods and services.
• Spread of diseases: Water-borne diseases such as cholera and gastroenteritis spread rapidly after floods.

2. Economic Impacts

• Loss of property: Destruction of infrastructure like houses, roads, and bridges.
• Economic losses: Floods in India lead to significant economic losses, with a total of $58.7 billion reported, accounting for 68% of the economic losses from all disasters.
• Impact on agriculture: Crops are adversely affected by floods due to the loss of fertile soil cover and disrupted agricultural seasons.
• Female employment: Studies show that flood damage negatively affects economic growth in the long run, especially reducing female employment opportunities in agriculture.

3. Environmental Impacts

• Affect ecology: Floods destroy the biodiversity of regions, and it may take years or decades for these areas to recover.
• Positive contributions: Floods can deposit fertile silt, recharging groundwater tables, which is beneficial for crops.
• Rivers: Riverbanks and natural levees can be eliminated, causing more flooding in the future.
• Contamination: Floodwater can pollute rivers and habitats, affecting irrigation and drinking water supplies.
• Invasive species: Floods help spread invasive species that damage local ecosystems.
• Species destruction: Floods kill animals in the affected regions.
  • Example: Floods in Assam often kill keystone species such as rhinos.

Flood Mitigation Strategies

• Floodplain zoning by state governments: The Rashtriya Barh Ayog (RBA) recommended floodplain zoning in 1976, but only a few states such as Rajasthan, Manipur, and Uttarakhand have passed these acts. Even in these states, implementation is poor.
• RBA’s recommendations: Identification of flood-prone areas should be better assessed for forecasting and mitigation.
• Plantation: Planting trees and mangrove belts along rivers and coasts can mitigate flood damage.
• Planning and empowerment: Empowering communities through planned settlement growth and economic strategies ensures they can rebuild more resilient structures.

Flood Mitigation Strategies

• Shared flood warning mechanisms: Cooperation between upstream and downstream regions or countries to share flood-related information across boundaries.
• Prevention of encroachment: Rejuvenating wetlands and preventing encroachment to restore natural flood-buffer zones.
• Shift from management to planning: Emphasizes the need to view floods as hazards (both natural and anthropogenic) and not just catastrophes, advocating for long-term flood governance planning.
• Embarkment: Strengthening or constructing embankments, new dams, and reservoirs with specific flood cushion provisions to mitigate flood risk.
• Desilting/dredging of rivers: Removing silt and sediment from rivers to restore capacity and improve hydraulic performance.
• Catchment area treatment/afforestation: Prevents soil erosion and improves water conservation to minimize sediment runoff.

Government Initiatives

• National Flood Risk Mitigation Project (NFRMP): Focuses on mobilizing resources for relief, rehabilitation, and recovery from floods while also promoting awareness.
• Flood Management Programme: Provides financial assistance to state governments for critical flood management efforts.
• Dam Rehabilitation and Improvement Project: Improves the safety and functionality of existing dams.
• River interlinking project: Connects rivers by manually creating canals and land areas, reducing excess water flow into the sea.

URBAN FLOODS 

Urban flooding is an increasing phenomenon in cities and towns due to heavy rainfall in a short period. Notable examples of urban floods include:

• Patna (2019)
• Chennai (2015)
• Mumbai (2005)

Major Causes of Urban Flooding:

• Lack of proper drainage: Inadequate drainage networks in cities.
• Dying water bodies: Water bodies in cities are drying up, reducing natural flood absorption.
• Encroachment of water bodies: Lakes and ponds are being encroached upon for infrastructure or waste disposal, reducing their flood absorption capacity.
• Disposal of garbage: Improper garbage disposal exacerbates urban flooding by clogging drainage systems.
• Climate change: Erratic and heavy rainfalls are becoming more frequent, increasing the likelihood of floods.
• India’s land policy: Ineffective management and political, social, and economic factors hinder the ability to control urban floods.

Suggestions to Tackle Urban Flooding

1. Responsibilities: Municipal authorities alone cannot handle the scale of urban floods. It requires collaboration across various levels of governance and civil society.
2. Funding: Urban flooding management needs concerted and focused investments in terms of energy, resources, and funds.
3. Mission Mode Setup: To address the issue effectively, flood risk mitigation should be approached through a “mission mode” setup with active involvement from civil society at metropolitan levels.
4. Mission Objectives: There should be clear objectives to mitigate flood risk while also ensuring water security for cities.
5. Sponge Cities Scheme: As urban areas struggle with impermeable terrain and increased rainfall, the concept of “sponge cities” becomes relevant. This involves designing cities to absorb rainwater naturally.
6. Urban Aquifers: Allow rainwater to filter naturally through the soil and recharge urban aquifers for better water management.
7. Groundwater Rejuvenation: Efforts should be made to extract water from urban or peri-urban wells, enhancing the groundwater table.
8. Water Treatment Facilities: Urban water treatment plants are essential to ensure water is purified and made available for consumption.

Measures to Prevent Urban Flooding (As Per NDMA Guidelines)

1. Early Warning System and Communication: Dissemination of real-time flood warnings, utilizing the latest technologies to provide accurate, actionable data where traditional methods fall short.
2. Design and Management of Urban Drainage Systems: Proper management is essential to ensure rainwater does not pool in one area, preventing floods caused by inadequate drainage.
3. Rainwater Harvesting: With urbanization reducing groundwater recharge, implementing rainwater harvesting becomes critical to manage runoff and mitigate flood risk.
4. Conservation of Water Bodies: Lakes, ponds, and tanks play a crucial role in capturing runoff and reducing the severity of floods in urban areas.
5. Response Systems: Emergency centers, incident response systems, flood shelters, and rescue operations must be established to respond swiftly to urban floods.
6. Sanitation: Ensuring proper sanitation to prevent the spread of waterborne diseases like malaria, dengue, and cholera following a flood.
7. Urban Flooding Cells: Separate Urban Flooding Cells (UFC) should be established at both the national and local levels to coordinate all flood management activities.