Do you know that between 1980 and 2017, India witnessed 278 floods, affecting nearly 750 million people?

The characteristic of India’s climate is highly influenced by monsoons that cause floods in different parts of the country. Floods are an essential hydrological component of the drainage basin and can occur due to various reasons.

Read on to know about major causes of flood and everything related to it.

Flood is a natural hazard where lands that are usually dry submerge under the overflow of water. Heavy rains can cause an overflow of water and can become a natural disaster if there is a great loss of people and property. Apart from heavy rain, multiple reasons can lead to a flood. Take a look at the causes of floods in India.

Common causes of flood can be divided into the factors triggering it. These factors include -

• Meteorological factors
• Physical factors
• Human factors

 Let’s discuss the factors causing floods in India.

1. Meteorological Factors

The natural causes of flood are discussed below -

• Heavy Rainfall: The season of monsoon enter India in mid-July and stays till the end of September. During this time, rainwater flows and is collected in dams. When this tired or collected water reaches beyond the storage capacity limit, it ends up in flood. Floods caused by rainfall usually occur at the sub-Himalayan plains of West Bengal, Indo-Gangetic, West coast region of West Ghat and Assam.
• Cloud Burst: Cloud Burst occurs due to intense precipitation in a short duration which can sometimes be accompanied by hail and storm and can cause a flood. These natural incidents occur at the mountain slopes, and water runs down towards the plains, causing a flood.
• Cyclone: Cyclones occur in a low-pressure zone where winds rotate inwardly. Cyclones can be accompanied by a massive storm and lead to extreme weather conditions. Four eastern coastal states in India, such as Tamil Nadu, West Bengal, Odisha, Andhra Pradesh, mostly suffer from cyclonic floods.
• Global Warming: Due to the increased rise in global temperature, glaciers of the Himalayan range start to melt. As a result, the seawater level also rises, causing floods in surrounding years.
• Earthquakes and Landslides: A shift in tectonic plates can lead to alteration in the volume and course of surface water resulting in flood hazard. During landslides, the flow of debris into the water surface increases the level of river sediment causing floods.

2. Physical Factors

Those wondering about what physical factors act as flood causes can get a clear idea from the following section.

• Insufficient Drainage Management: Improper planning of the drainage system of an area can cause excess water due to heavy rainfall to get stuck and lead to a flood.
• Catchment Area: Catchment area is an area from where the rainfall water flows into a river. This can be a lake or reservoir. During monsoon, when excess water exceeds the limit of holding capacity of the catchment area, it leads to floods.

3. Human Factor

Following is a list of human causes of flood -

• Siltation: Siltation refers to the flow of silt and sediments in the riverbed. As particles remain suspended in the river and accumulated in the riverbed, it disrupts the flow of the river, causing a flood.
• Improper Agricultural Practices: If farmers are not cautious of the effects of farming practices meaning if they leave the waste material into the river or cannot handle water management properly, it can lead to a flood. 
• Deforestation: Deforestation is one of the major human causes of floods. Trees act like a sponge that helps to hold soil and water and prevent flooding. As trees are being cut down at a fast pace to make way for urbanisation to grow, more water runs towards a river during heavy rainfall. As a result, a flood occurs.
• Collapse of Dams: Dams are built to store water and provide water to people. As dams are human-made, these can be worn out and subsequently collapse causing floods. Also, if heavy rainfall sustains for a long time, State Governments often declare to open dam gates which can lead to a dangerous flood.

The piece mentioned above clearly describes what the causes of floods are. Now let’s learn about the types of floods.

Floods can be of 6 types. These are -

• Coastal Floods: Coastal floods occur when strong winds or storms move towards the coast during high tide.
• Flash Floods: Flash floods usually occur in hilly areas in limited space. Here the sudden heavy rainfall or snow thaws are the causes of flooding. The fast-moving torrent of Flash floods can sweep large objects such as cars, rocks and everything that comes in their path.
• River Floods: River floods occur due to the inflow of water from heavy rainfall, snowmelt or powerful storms.
• Pluvial Floods: Pluvial floods occur in areas that cannot hold rainwater and end up forming puddles and ponds. These types of floods are the event of rural areas.
• Urban Floods: When the drainage system of urban areas fails to absorb rainwater, it creates urban floods.
• Groundwater Floods: Incessant rainfall can increase the water level present in soil underground making it saturated. Significant rise in water level above the ground’s surface leads to flooding.

By now, you must have learnt about what are the main causes of floods and the types of floods. Now, let’s focus on the impact of floods in India.

The consequences of flood depend on the location, duration, and vulnerability of the area. The impacts of floods affect both individuals and communities and have social-environmental consequences. Below is a list of damage caused by floods.

• Human Loss and Property Loss: Every year, millions of people become homeless and washed away due to floods.
• Spread of Communicable Diseases: Waterborne diseases like cholera, typhoid fever, hepatitis, and leptospirosis spread in flood-affected areas. Floods also lead to vector-borne diseases, transmitted through parasites and pathogens such as a mosquito. As a result, the health of flood victims deteriorates.
• Destruction of Crops: Every year, floods destroy a large number of crops.
• Loss of Livestock: Like humans, livestock also get displaced during floods and die due to the loss of their habitats.
• Disruption of Communication Link and Transportation: Flood causes damage to transportation links such as bridges, rail, power plants etc., thus causing communication disruption in those areas.
• Economic and Social Disruption: The economy comes to a standstill as people are forced to move to another place, and revival of this situation takes time.

Apart from learning about the impact of floods, individuals must know about flood-prone areas.

Read along!

Below is a list of flood-prone zones or areas in India.

• Punjab
• Haryana
• North Bihar
• West Bengal
• Uttar Pradesh
• Coastal Andhra Pradesh
• Odisha
• Southern Gujarat
• Brahmaputra Valley
• Ganga River Basin 
• North-west region of River Narmada and Tapti
• Deccan region near River Mahanadi, Krishna and Kaveri

Residents can reduce the impacts of floods in these above-mentioned areas with some preventive measures.

Take a look at the following section!

• Planting Mangroves: In order to prevent coastal flooding, State Governments must actively take part in planting more mangroves in coastal areas. Mangroves act as a robust barrier against floods. Hence, governments must focus on mangrove conservation in coastal areas.
• Optimising Technology: Advancement in technology can help to predict floods. Here, using intelligent flood warning systems like IFFLOWS can prove to be extremely beneficial.
• Taking Structural and Non-Structural Measures: Structural measures refers to the physical changes or acts (such as redesigning buildings or designing physical barriers to disasters) to protect against a flood. On the other hand, non-structural measures refer to bringing social solutions such as planning evacuation, preparing for emergency situations in flood. These two types of measures during a flood can help to reduce the impacts of floods in India.

To protect one’s home from the damage caused by floods, individuals can buy flood insurance.

Flood Insurance: Flood insurance is a type of property insurance that covers the losses due to flooding (caused by heavy rainfall, melting snow, coastal storm, seawater entering the city due to tidal waves etc.). Flood insurance is a segment of home insurance where eligible candidates can get compensation for repairing houses.

Now that individuals have learnt about the causes of flood, types of floods, flood-prone areas, they can identify their location and take precautions (such as buying flood insurance) accordingly.