1. Mention the examples of past floods in India
2. Quote the reasons for frequent flooding
3. Suggest steps to prevent floods
India is considered as the world’s most disaster prone country on account of its unique geo-climatic conditions. According to the Geological Survey of India (GSI), the major flood prone regions cover almost 12.5% area of the country. It is estimated that over 90 per cent of the total damage done to property and crops in India is done in the Plains of Northern India.
The reasons responsible for frequent flooding in India are as follows-
A) Man made Reasons:
1. Floodplains of several rivers, especially in the northern plains like Kosi, Ghaghra, Gandak, Sarayu etc are flooded every year. Yet, these areas have been settled by people, usually lying in the lower economic-strata. This has led to recurring losses in the face of floods, especially in the Assam and Bihar plains.
2. The destruction of natural wetlands including marshes and lakes has led to blocking of areas that had earlier served as water sinks. This is the primary reason behind Chennai floods.
3. Construction of houses in a haphazard manner without getting plans approved has led to washing away of several buildings during flash floods due to cloudbursts in the Himalayan region.
4. With increasing deforestation especially along coastal areas and river banks, the first line of defence against floods has been removed. This is the reason that cyclone caused floods result in severe destruction along the coasts.
B) Physiological Reasons:
Heavy precipitation: Heavy rainfall is one of the major reasons of the flood in India. Over natural bank of rivers, the rainfall of about 15 cm or more in a single day exceeds the carrying capacity of rivers causes a flood in that region. Such effect can be seen in the West Coast region of the Western Ghat, Assam and sub-Himalayan West Bengal and Indo-Gangetic plains.
Rise in river bed: The river bed rises due to large silt and sand gradients carried by the Himalayan Rivers. The deposition of silt enhances the catchment area of rivers which reduces the carrying capacity of rivers.
The meandering tendency of river-flow: The tendency to meander or change the course within a specific boundary of rivers in the flat terrains also causes a flood in the meandering regions like lower reaches of the Brahmaputra and Gangetic plains.
Silting in Delta areas: The deposition of silt on the river-mouths by the sea tides deteriorates the discharging capacity of rivers which causes a flood in that region.
Earthquake and Landslide: Sometimes it has been found that the river changes its course after the natural calamities like earthquake, landslide which causes a flood in the same region. Such instances can found in the mountain of hilly region states like Jammu and Kashmir, Himachal Pradesh, and Uttarakhand etc.
Obstruction of free-flow of rivers: Roads, embankments, railway lines, canals etc. obstructs the free flow of rivers leading to flood in the area.
Cloudburst: Cloud bursts lead to a high amount of rainfall within a short time leading to flash floods. Flash flood generally occurs in the Himalayan region.
The measures to control flooding in India is Flood governance through resilience:
This could be an outcome of three broad sets of action: Reducing vulnerability, increasing access to services, and maximising productivity through optimal use of available resources.
The dominant narrative of flood protection includes measures such as embankments, dredging rivers and bank strengthening.
Community-based advance flood warning systems, for example, have been successfully piloted in parts of Assam.
Strategic environment assessment of development activities, a practice followed in several countries needs to be undertaken in flood prone areas like the Brahmaputra basin.
Strengthening planning authorities like the Brahmaputra Board and flood control departments by staffing them with scientists from a wide range of disciplines is essential.
Focus should shift from relief measures to building resilience in flood-prone areas.
A community involvement and awareness generation is necessary for sustainable disaster risk reduction.
Scientific fish farming on the water bodies and the inundated land can ensure that inundation, when it cannot be avoided, is put to optimal use
A holistic and proactive approach is necessary in order to mitigate natural disasters like floods.
Development of GIS (Geographical Information System) based National Database for disaster management. GIS is an effective tool for emergency responders to access information in terms of crucial parameters for the disaster affected areas.
In any disaster management system the warning system plays a very crucial role along with technology
natural water bodies soak up excess rainfall and use it to replenish groundwater
inter-related drainage systems created by these ponds, streams, lakes and channels then release the excess water into larger water bodies — oceans and big rivers.
Disaster risk reduction has a pivotal role in supporting adaption to climate change as well as sustainable development. Therefore, flood-prone regions of the country require a focused approach from both the Centre and state governments.