Urban Flooding (Disaster Management)

Urban Flooding (Disaster Management)

This article deals with ‘Urban Flooding (Disaster Management).’ This is part of our series on ‘Disaster Management’, an important pillar of the GS-3 syllabus. For more articles, you can click here.


Urban Flooding  (Disaster Management)

Urban flooding refers to the situation in urbanized regions where there is an overflow of water due to inadequate drainage capacity. This occurs when stormwater accumulates in urban areas and is unable to find an outlet, leading to inundation and waterlogging.

Causes of Urban Flooding

  • Encroachment of Flood Plains, Mangroves, Wetlands, Lakes, etc.: Rapid urbanization has led to the encroachment and destruction of natural water bodies that act as natural buffers against flooding. For example, 
    • Bengaluru: There were 260 lakes in 1960 and 10 now
    • Mumbai: Mangroves and salt pans have been destroyed for constructing high-end residential buildings 
    • Chennai: Encroachment of wetlands and flood plains 
  • Unprecedented Rainfall: Indian cities experience heavy rainfall during the south-west monsoons. The average monthly rainfall in Mumbai in July is 868 mm. Such intense rainfall events overwhelm the drainage systems and cause urban flooding.
  • Cyclones and Hurricanes: India’s extensive coastline exposes it to tropical cyclones. The development of coastal cities and towns makes them vulnerable to inland flooding and storm surges caused by cyclones.
  •  Unpreparedness in Urban Planning: Many cities lack adequate urban planning and infrastructure to handle urban floods. Unlike cities like Tokyo, which have invested billions in building water discharge tunnels and advanced drainage systems, Indian cities often lack such preparedness.
  • Concretization of Cities: The extensive use of concrete and asphalt in urban areas reduces land permeability. It prevents water from seeping underground, increasing surface runoff and exacerbating the risk of urban flooding.
  • Urban Heat Island Effect: The phenomenon of urban heat islands, where cities experience higher temperatures than the surrounding countryside, can influence rainfall patterns. The hot air over cities can cause rain-bearing clouds to be pushed up, resulting in highly localized and intense rainfall events.
  • Global Warming: Climate change has led to unexpected and extreme changes in rainfall patterns. For instance, Chennai experienced unusually high rainfall in November 2015, with 1200 mm compared to the average of around 400 mm. 
Cities facing Urban Flooding in India

Case Studies

1. Global Examples

1.1 Kuala Lumpur

  • Kuala Lumpur, Malaysia’s capital city, has faced significant challenges with urban flooding due to its geographical location and heavy rainfall.
  • To address this issue, the city has implemented an innovative solution by constructing extensive water discharge tunnels. Tunnels divert excess floodwater away from the city’s densely populated areas. By creating an alternative pathway for water to flow, these tunnels alleviate the burden on the city’s drainage systems and prevent overwhelming floods.

1.2 Tokyo

  • Tokyo constructed a stormwater management system that includes the construction of reservoirs, underground storage facilities, and permeable surfaces to help capture excess rainwater and prevent it from overwhelming the drainage system.
  • Tokyo has prioritized the incorporation of green infrastructure, which can absorb rainwater and reduce runoff.
  • Installed Early Warning Systems

2. Indian Examples

2.1 Davangere (Karnataka)

Davangere faced recurring urban flooding due to heavy rainfall and inadequate drainage systems. To address this issue, the following was done.

  • Improved the city’s stormwater drainage infrastructure 
  • Desilted water channels
  • Created storage ponds and reservoirs to hold excess water during heavy rains temporarily 

2.2 Agartala (Tripura)

Agartala experienced significant urban flooding due to its geographical location and heavy rainfall patterns. To mitigate the impact of flooding, the city authorities adopted various measures. 

  • Construction of flood protection embankments and bunds along vulnerable areas
  • Development of rainwater harvesting structures, such as ponds and recharge pits, to capture and store rainwater, thereby reducing the burden on the drainage systems. 
  • Improved its sewage and stormwater drainage networks 

Disaster Management for Urban Flooding

Disaster Risk Reduction (Before Urban Flooding)

  1. Disaster Mapping: Conducting comprehensive risk assessments to identify vulnerable areas prone to flooding using geographical and historical data.
  2. Infrastructure Development: Constructing and maintaining flood protection infrastructure such as embankments, levees, and floodwalls and developing reservoirs, retention ponds, and water storage facilities for floodwater management.
  3. Early Warning Systems: Establishing advanced meteorological monitoring systems to predict heavy rainfall and extreme weather events and alert residents and authorities about impending floods.
  4. Conducting public awareness campaigns to educate residents about responding to incidents of urban flooding

Disaster Response (During Urban Flooding)

  1. Emergency Response: Activating emergency response teams and evacuating residents from high-risk areas to designated shelters or safer locations.
  2. Communication and Coordination: Establishing emergency helplines and control rooms to address queries and provide assistance.

Recovery and Rehabilitation (After Urban Flooding)

  1. Damage Assessment and Recovery: Conduct rapid damage assessments to determine infrastructure damage and losses.
  2. Long-Term Measures:
    • Conducting post-flood analysis and evaluating the effectiveness of existing flood management strategies.
    • Updating flood risk maps and revisiting urban planning regulations based on lessons learned.
  3. Capacity Building: Training and equipping local authorities and emergency response teams to handle future flood events effectively.

Measures Taken by the Government

1. Standard Operating Procedures (SOP) for mitigating Urban Flooding by the Central Government under the Atal Mission for Rejuvenation and Urban Transformation (AMRUT). It lays down a predefined set of directives or responsibilities for public agencies in a city/town in 3 phases: 

  1.  Pre-Monsoon Phase: Preparedness and Planning for Disaster Reduction.  
  2. During Monsoon Phase: Early Warning, Effective Response and Management, and Relief planning and execution
  3. Post-Monsoon Phase: Restoration and Rehabilitation.

2. Sponge Cities Plan by Urban Local Bodies and State Governments to make cities more permeable. Sponge cities involve the use of porous materials and technologies to improve the city’s capacity to absorb rainwater. E.g. use of permeable material for roads and pavement, contiguous open green spaces, green roofs, etc.

3. National Guidelines on Management on Urban Flooding by the National Disaster Management Authority (NDMA)   

Flood (Disaster Management)

Flood (Disaster Management)

This article deals with ‘Flood (Disaster Management).’ This is part of our series on ‘Disaster Management’, an important pillar of the GS-3 syllabus. For more articles, you can click here.


Flood (Disaster Management)

The term “flood” is commonly used to describe a situation where the water flowing in rivers, streams, and other bodies of water cannot be contained within natural or artificial banks. 

Floods occur regularly in India, affecting approximately 10% of the country’s total area. However, the impact and frequency of floods have increased due to climate change.

Cause of Floods

Natural Causes

  • Heavy precipitation: India receives all the rainfall in just 4 months. During that period, the discharge of water in the river increases than the capacity of the river, resulting in floods.
  • The river changes its course due to various reasons, such as landslides. By blocking the flow of streams, the landslides cause massive floods.
  • Events such as cloud burst, which results in massive water discharge in a very less period
  • Climate Change: Climate Change led to increased variability in rainfall patterns, with some areas experiencing prolonged dry spells followed by heavy rainfall in a short period. This change in rainfall patterns contributes to flash floods.

Manmade Causes

  • Settlement in Flood Plains: Many towns and cities have been established in floodplains, which are low-lying areas adjacent to rivers and prone to flooding during heavy rainfall or when rivers overflow their banks.  E.g., Construction activities in low-lying areas, such as Alapuzha in Kerala, have made these regions highly vulnerable to flooding.
  • Destruction of Natural Wetlands around the Cities: Wetlands play a vital role in controlling floods by acting as natural sponges that absorb excess water during heavy rains. However, the destruction and encroachment of wetlands for urban development and agriculture have significantly reduced their capacity to absorb and store water. 
  • Environmental Degradation: The Gadgil report on the fragile ecosystem of the Western Ghats, released in 2011, highlighted the detrimental effects of illegal mining and deforestation in the region. These activities have led to extensive encroachment on river fronts, resulting in reduced river carrying capacity and increased siltation in reservoirs located in the Western Ghats. 
  • Deforestation and Soil Erosion: Deforestation, particularly in hilly regions and catchment areas, has a significant impact on flooding in India. Trees and vegetation help to retain rainwater, reduce surface runoff, and stabilize the soil. When forests are cleared for agriculture, urban expansion, or other purposes, the protective cover is lost, leading to higher rates of soil erosion. Increased soil erosion results in more sediment being carried by rivers, leading to siltation and reduced carrying capacity, which in turn contributes to floods.
  • Faulty Dam Management: Dam failures, the release of excessive water during heavy rainfall, or sudden discharges without adequate warning can lead to downstream flooding.  The 2018 floods in Kerala revealed shortcomings in dam management. The dam authorities were unable to assess the situation accurately and failed to provide timely warnings to the affected communities.

Side Topic: Flash Floods

Flash floods are an extreme manifestation of flooding that takes place within a significantly compressed timeframe, resulting in rapid and intense inundation. Unlike conventional floods that may unfold over a longer period and affect larger regions, flash floods are highly localized. 

Causes of Flash floods in India

  1. Cloudbursts: Cloudbursts are sudden, intense rainfall events that occur within a short period in localized areas that overwhelm drainage systems.
  2. The concentration of rainfall during the monsoon season: India receives nearly 75 per cent of its total rainfall during the monsoon season. This concentrated rainfall puts a significant burden on the rivers.
  3. Water exceeding the Dam’s Capacity: Flash floods can also occur when the water level in a dam exceeds its capacity. 
  4. Glacial Lake Overflow: In regions with glaciers, flash floods can be triggered by the overflow of glacial lakes. 

Factors like poor drainage infrastructure, deforestation, and urbanization can also exacerbate the risk of flash floods in certain areas.

Impacts of Floods


  • Loss of life and property: Floods can lead to tragic loss of life and widespread destruction of homes, buildings, and infrastructure.
  • Damage to infrastructure: Floodwaters can cause significant damage to roads, bridges, railways, and other infrastructure. 
  • Mass Migration and Economic Disruption: In the aftermath of floods, people may be forced to evacuate their homes. This mass migration can disrupt the social fabric and economic activities.
  • Disease Outbreaks: Floods can create favourable conditions for the outbreak and spread of waterborne diseases, such as cholera, typhoid, and dysentery.
  • Public discontent and loss of trust: When floods occur frequently or result in extensive damage, people may become dissatisfied with the government’s response eroding their trust in the government’s ability to handle future disasters effectively. 


  • Increased Soil Fertility: Floods can deposit nutrient-rich sediments onto agricultural lands, improving soil fertility. 
  • Water Recharge of Natural Aquifers: Floodwaters can infiltrate into the ground, replenishing natural aquifers and underground water reserves. 
  • Renewal of Wetlands: Floods can play a vital role in renewing and restoring wetland ecosystems.

Ways to deal with Floods

Hard Management Techniques

  1. Dams: Dams play a crucial role in flood management by trapping and storing water during heavy rainfall or snowmelt periods. The stored water can then be released gradually during dry spells.
  2. Embankments or Artificial Levees: These structures are built along riverbanks to contain floodwaters within the river channel, preventing them from spilling into surrounding areas. 
  3. Interlinking of Rivers: Connecting rivers through canal systems or diversion channels can help manage floods by diverting excess water from one river to another.
  4. Flood Walls/Coastal Defences: These structures are constructed around settlements, particularly in coastal areas, to protect them from the impact of floods and storm surges.  
  5. Storage Areas: Constructing temporary storage areas, such as reservoirs or lakes, allows excess water to be pumped out of rivers during flood events.
  6. Dredging the River Basins: Dredging involves removing sediments, debris, and vegetation from river channels, increasing their capacity to carry water. 

Soft Management Techniques

  1. Washlands: Certain sections of the floodplain, known as washlands, are intentionally allowed to flood. These areas are often designated as sports fields or nature parks, serving as controlled flood zones.
  2. Flood Plain Zoning: This technique involves establishing regulations and land-use policies that restrict or discourage development in flood-prone areas.
  3. Afforestation: Planting trees and vegetation in flood-prone areas can help manage floods. The roots of trees absorb water and stabilize soil, reducing erosion and the likelihood of flash floods. 
  4. Warning Systems: Implementing early warning systems can provide timely information about impending floods.
  5. Hydrological Data Sharing: Cooperation and sharing of hydrological data among countries in the upper catchment area of a river basin are vital for effective flood management.

Capacity Building

  1. Flood Education: Raising awareness and providing education about floods, their causes, and appropriate responses can empower communities to better prepare and respond to flood events. 
  2. Emergency Search and Rescue: Developing specialized search and rescue teams trained in flood response can significantly improve emergency operations. 
  3. Emergency Relief: In the aftermath of a flood, providing short-term housing, food, safe water, access to healthcare, and protection for vulnerable groups such as women, children, and the elderly is essential. 

Other Measures

  1. There is a need to promote flood-tolerant “scuba rice”, sugarcane, jute and high-value aquatic crops in regions frequently hit by floods. 
  2. Formulate Nation-wide Silt Management Policy

Concept of the Disaster Management

Concept of the Disaster Management

This article deals with ‘Concept of the Disaster Management.’ This is part of our series on ‘Disaster Management’, an important pillar of the GS-3 syllabus. For more articles, you can click here.


  • Natural disasters and crises have been an integral part of human history. The evidence of this can be seen in the rise and fall of the Babylon and Indus Valley civilizations.
  • According to UN statistics, natural disasters kill 1,00,000 people on average and cause property damage worth billions of dollars annually. 
  • Among the top ten natural disaster-prone countries, India stands second after China.

Life Cycle of Disaster

A crisis doesn’t occur abruptly; it goes through a progression that can span from days to months or even decades, contingent upon the factors that give rise to it.

Concept of the Disaster Management

Response at Various Stages of Disaster (in General)

Concept of the Disaster Management

1. Risk Reduction

Disaster risk can be reduced by forecasting the occurrence of hazards well in time and preparing in advance for their onset.  

Methods for Risk Reduction /Mitigation

1. Disaster Mapping

Create a Disaster Map taking the following into account

  • Which disasters are occurring in the area? It can range from natural disasters like earthquakes, floods, hurricanes, and wildfires, to human-induced disasters such as industrial accidents or civil unrest.
  • Analyze historical data to determine the frequency of disasters occurring in the area.
  • Social fragility, i.e. to what extent society is prepared to cope with disaster.
  • Vulnerable populations within the area, such as the elderly, children, people with disabilities, low-income communities, and marginalized groups.

2. Preparation of District Disaster Plans

  • Each District should prepare a District Plan involving all the stakeholders. These stakeholders include government officials, emergency management agencies, local communities, non-governmental organizations, and other critical actors involved in disaster risk reduction and response.

3. Mock Drills

  • All disaster management plans should be tested periodically through mock drills. They involve simulating emergencies and evaluating the response of disaster management plans and procedures.

4. Construction of Major Civil Engineering Structures

These include engineering solutions to prevent disasters, such as 

  • Construction of dams 
  • Diversion channels
  • Cyclone shelters
  • Shelterbelt plantations  
  • Regeneration of mangrove belts in coastal areas

5. Construction of Disaster Resistant Dwellings

  • Disaster Resistant Dwellings are designed and constructed in a manner that reduces vulnerability to various hazards, such as earthquakes, floods, cyclones, and landslides. The National Building Code of India (NBC) plays a significant role in providing guidelines for constructing disaster-resilient buildings 

6. Effective Implementation of Laws

Effective implementation of laws plays a crucial role in disaster risk reduction. Industrial disasters and urban floods often occur due to inadequate planning and weak enforcement of existing laws and regulations. Two notable examples are the Uphaar tragedy and the Bhopal Gas tragedy.

  1. The Uphaar Tragedy, which took place in 1997, involved a fire in the Uphaar Cinema in Delhi, leading to the loss of 59 lives. This incident highlighted the consequences of inadequate safety measures and poor enforcement of regulations in public spaces.
  2. The Bhopal Gas Tragedy of 1984: A gas leak at the Union Carbide pesticide plant in Bhopal resulted in thousands of deaths and long-term health issues for survivors. This incident exposed the shortcomings in industrial safety measures.

7. Installing Early Warning System

Early Warning System and Disaster Management
  • Early Warning Systems are designed to provide timely alerts and warnings regarding upcoming disasters, allowing authorities and communities to take necessary actions to mitigate the potential impact. 
  • The importance of early warning systems has been exemplified by notable events such as the Mexico Earthquake in 2018, where a significant number of lives were saved due to the existence of such a system.
  • Recognizing the significance of early warning systems, the Sendai Framework for Disaster Risk Reduction, a global agreement adopted in 2015, also emphasizes their implementation as a critical component of disaster risk reduction strategies.
  • India has already installed an Early Warning System for Cyclones, Tsunami, Heatwaves etc. 

8. Education

  • Disaster management education needs to be integrated and institutionalized within the formal and informal education systems.
  • The Central Board of Secondary Education (CBSE) has already made significant strides in this direction. They have taken proactive steps to incorporate disaster management education into the curriculum. 

Case Study: Super Cyclone (1999) vs Cyclone Phailin (2013)

The Super Cyclone and Phailin Cyclone case studies show the importance of Disaster Risk Reduction. 

Super Cyclone (Odisha, 1999) 

  • Wind speeds of 270-300 km per hour  
  •  10,000 people killed and lakhs of livestock population. 
  • Over 2 million houses were damaged.

But this damage could have easily been reduced.

Cyclone Phailin (2013)

  • Early Warnings were given to residents near Bhubaneshwar about an impending Cyclone which struck within a week 
  • Casualties were just 50 people dead 

Recent Cyclone Varda in Tamil Nadu & Cyclone Hudhood also showed a similar trend with a death toll not exceeding 10. But the damage to infrastructure is still high. Now reaching the next level, the concern is how to address losses occurring to property – roads, bridges, housing, hospitals, electricity etc. (Note: Sendai calls for a reduction in mortality and the destruction of infrastructure).

2. Emergency Response System / During Disaster 

The Emergency Response System is a comprehensive framework encompassing various components to manage and respond to emergencies effectively.

Components of Emergency Response System

1. Acting on Early Warning System

  • Installing warning systems is not an end in itself. The effectiveness of these systems relies on the ability of the administration to swiftly respond and take appropriate action upon receiving the warning.

2. Rescue

  • Rescue operations must be carried out rapidly as the window of opportunity is usually small.  
  • Using a Disaster map, the most vulnerable points can be identified & resources can be mobilized to rescue people from those areas first. 

3. Quick Trauma Care

After Rescue, the injured must be transferred to the appropriate Trauma Care Facility within the Golden Hour (Golden Hour = first hour after sustaining injury). During this critical Golden Hour, prompt medical intervention can significantly increase the chances of survival and minimize long-term complications for the injured. 

4. Relief

As the rescue operations are on, the phase for providing relief starts. 

  • Ensure that the basic minimum necessities of life, like food, clothing, shelter, security, and basic health and sanitation facilities, are available. 
  • Trauma care and counselling should be made an integral part of the relief operations.

Recovery & Rehabilitation / After Disaster

Recovery differs in different disasters

  • The damage caused by floods, earthquakes and cyclones is much larger than other disasters, and recovery after these disasters pose a challenge. 
  • In disasters like drought, the relief phase is prolonged, and since there is no damage to the infrastructure and property, the rehabilitation is confined to the restoration of livelihoods. 
  • Industrial disasters being quite varied in nature, the rehabilitation in major ones like the ‘Bhopal Gas Tragedy’ could involve rehabilitation efforts spanning over a generation of victims.  

Recovery & Rehabilitation Process

  • The first step is to assess the damage and make a recovery & rehabilitation strategy considering economic, social, political and psychological factors.
  • Under Sendai Framework, the main principle to be followed is – BUILD BACK BETTER. The infrastructure that is to be built should be such that they can survive the next disaster. 
  • Following any major disaster, several players arrive on the scene & ensuring proper coordination among them becomes very important. Without coordination, it leads to duplication of efforts in some areas & gaps in others.   
  • Usually, it is seen that the recovery efforts tend to taper off with time. This decline in recovery effort over time needs to be arrested.