The Hindu Editorial Analysis - 29th September 2022 | Current Affairs & Hindu Analysis: Daily, Weekly & Monthly - UPSC PDF Download

In Nature’s Warning Signs, a Nudge to Riparian States 

Context:

• There has been an increase in the magnitude, the frequency and the intensity of foods in many parts of the world. 
• In June this year, Assam experienced one of its worst foods in living memory which affected over 30 districts.

Flood

• Flood is an overflow of a large amount of water beyond its normal limits, especially over what is normally dry land.

Flood Prone Areas in India

• Punjab
• Haryana
• North Bihar
• West Bengal
• Uttar Pradesh
• Coastal Andhra Pradesh
• Odisha
• Southern Gujarat
• Brahmaputra Valley

 Major Causes of Flood in India

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

• Meteorological Factors
  • 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.
•  Physical Factors
  • 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.
• Human Factor
  • 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.

 Types of Flood

• 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.

 Damages Caused by 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.

 Flood Management

Approaches to dealing with floods may be any one or a combination of the following available options:

• Attempts to modify the flood
• Attempts to modify the susceptibility to flood damage
• Attempts to modify the loss burden
• Bearing the loss.
• The main thrust of the flood protection programme undertaken in India so far has been an attempt to modify the flood in the form of physical (structural) measures to prevent the floodwaters from reaching potential damage centres and modify susceptibility to flood damage through early warning systems.

Structural measures

The following structural measures are generally adopted for flood protection:

• Embankments, flood walls, sea walls
• Dams and reservoirs
• Natural detention basins
• Channel improvement
• Drainage improvement
• Diversion of flood waters.

 Non-structural measures

• Flood forecasting and warning
• Floodplain zoning
• Flood fighting
• Flood proofing
• Flood insurance.

Other

• 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.
• Optimizing Technology: Advancement in technology can help to predict floods. Here, using intelligent flood warning systems like IFFLOWS can prove to be extremely beneficial.
• Channelisation: Channelisation is a deliberate attempt to alter the natural geometry of the river. Channelisation can be achieved in many ways. The river can be deepened and widened to increase the capacity of the channel. This increases its hydraulic efficiency and allows a larger discharge to be contained within the channel. This will help prevent flooding. The channel can be made straighter, through the use of artificial cut-offs.
• Afforestation: During heavy rains, trees reduce the risk of flooding. There are two major ways in which trees provide protection against flooding. Experts say that woodland acts as a barrier to floodwater, while trees also prevent soil erosion, reducing sediment going into rivers and increasing water absorption into the ground. This slows rainwater running off into swollen streams and helps lower peak flood levels.

Way Forward

Disaster Preparedness Plan

• A comprehensive flood management plan is needed to include Disaster preparedness.This may require strengthening of the following:
  • Flood Hotspot Mapping at local and regional scale.
  • Management and regulation of riparian zones to prevent spilling and erosion.
  • River flood modelling to prepare for incidences like reservoir breach and emergency water release from dams.
  • Advanced techniques such as mapping based on satellite imagery and Geographic Information Systems will help in development of flood early warning systems.

Integrated Approach

• Steps need to be taken for watershed management through an integrated approach. Often these approaches involve both hard engineering solutions and ecologically sustainable soft solutions.
  • Hard Solutions: It involves civil engineering construction such as dams, culverts and dykes, widening and deepening of river channels and diversion channels to store and divert water to increase the lag time of water reaching downstream.
  • Ecological Soft Solutions: The solutions such as restoration and management of riparian zones, afforestation along the river channels which led to retention of rainwater and reduces the river discharge.
• An integrated approach to managing floods requires a sound understanding of the patterns that rivers such as the Ganga and its tributaries display during the monsoon.

Prioritising Buffers, Flexibility and Adaptability

• This includes reviewing safety criteria of dams and canals, re-building these with higher safety factors, creating new intermediate storages, and introducing dynamic reservoir management.

Reducing Disaster Risk Reduction

• There is a need for efficient implementation of Sendai Framework for Disaster Risk Reduction, this will reduce the vulnerability of any disaster.

Focusing on Urban Flood Management

• Keeping in view the fact that the problem of Urban Flooding is becoming more severe and losses are mounting every year.
• The subject of urban flooding needs exclusive attention and the proper implementation of NDMA guidelines on Urban Flooding 2016, is the need of the hour.