As Assam Floods Affects 7 Lakh, India's Flood Situation Explained

As per the Assam State Disaster Management Authority, around 6,80,931 people have been affected in 17 districts due to floods in the state. Around 5,000 people are staying in 62 relief camps.

India Meteorological Department (IMD) has predicted heavy rainfall at isolated places in Assam.

Reportedly, this year’s flooding and landslide cost 62 persons their lives across the state, 38 of these were killed by flood and 24 by landslides.

Have floods become more common?

Due to climate change, erratic and extreme weather events are set to increase. India ranks fifth on the climate change risk index. In all likelihood, extreme and sudden railfall events will result in floods and landslides.

In 2019, the monsoon across India was around 33 per cent in deficit in June, however, by August, it was a whopping 34.9 per cent above normal — the monsoon’s unpredictability is increasing with fewer rainy days and more extreme precipitation.

2019 also saw calamitous floods in different parts of the country — Kerala, Madhya Pradesh, Rajasthan, Gujarat, Assam and Bihar.

However, Central Water Commission (CWC) data shows that the relative loss of human, cattle lives, economic damages have come down since 1970s. The losses are the highest for the north Eastern states and Himachal Pradesh. Hilly regions suffer due to flash floods which are more difficult to predict and cause landslides.

How are floods in Mumbai different, say, from that in Assam?

Mumbai often sees urban floods after an extreme weather event like sudden rainfall, cyclone etc. On the other hand, in the Ganga Brahmaputra plains, floods are an annual natural occurrence. These are called riverine floods as they come after the river swells from the monsoon rains.

Urban floods are mostly caused due to anthropogenic reasons - poor urban planning - and while riverine floods are natural, they are also exacerbated by anthropogenic interventions like destruction of forests.

Urban floods, on account of being unpredictable and sudden need a focus on prompt relief and rescue. Riverine floods are an annual occurrence. They require structural interventions, institutional reforms and building resilience in the riverine population.

What are anthropogenic factors that exacerbate floods?

Number one would be poor urban planning. It often results in destruction of natural drainage and wetlands that act as a reservoir of the water in the event of rainfall. The concrete ground is non-porous and doesn’t allow the water to percolate and recharge the ground water aquifers.

In Indian cities, the storm-water drainage isn’t properly prepared for the monsoon rains. Ideally, the drains should’ve been widened given the population pressure. Over that, they are often choked with plastic litter and the storm water merges with sewage. This turns clean rainwater into polluted water which then collects into local water bodies and pollutes them, spreading diseases.

In many cases, the water bodies are turned into landfills, encroached upon for construction.

The vast area of alluvial plains from Maharajganj in Uttar Pradesh to Karimganj in Assam’s Barak valley is densely populated. Since most people depend in agriculture and settle in riverine areas, it is impossible to relocate them.

Embankments continue to be the most popular engineering solution but embankment management is poor. People continue to live inside embankment area, and even those in the safe areas live in constant fear of embankment breach.

The dams are supposed to mitigate floods, but they get silted quickly and water has to be released, causing floods downstream. Dredging is costly and porcupine structures built to counter erosion are often washed away due to subpar quality.

What can India do?

Riverlinking is cited as a solution, but it is not going to happen overnight, and only a thorough Environmental Impact Assessment will make clear the pros and cons. Excessive dependence on structural measures has failed to control the floods in the past.

On the other hand, administrative reforms — moving from a flood protection to flood governance approach — can give immediate results. Reducing vulnerability of the population, ensuring access to development services and optimal use of people’s resources can limit the damage caused by floods.

Odisha’s community-based disaster management in the face of frequent cyclones has many lessons to offer. The state has built multipurpose cyclone/flood shelters with the local sarpanch as in-charge and trained youth relief volunteers.

Odisha’s Disaster Management Authority has been a pioneer nationally and it’s Rapid Action Force has raised a number of battalions for prompt rescue.

NCCR-developed Chennai Flood Warning System (C-FLOWS) can predict flooding due to heavy rainfall, sea-level rise and increase in water levels of the three rivers — Cooum, Adyar and Kosasthalaiyar — that traverse the city two weeks ahead of the event.

For prompt rescue and relief, flood zonation is important.

CWC data shows that while in the 1970s the biggest flood related economic loss was due to the damage to crops, today, it’s the public utilities. Disaster-resilient infrastructure should, therefore, be a priority.

It is also important to recognise the link between water scarcity and floods. Each city should try to become as water sufficient as possible. Decentralised wastewater, solid waste management, rainwater harvesting, and integrated basin management is needed.

Cities should mimic the natural systems, allowing infiltration through low impact development, more green spaces and “room for the river”. Instead of routing it away, stormwater can be retained in aquifers, lakes and farm ponds for use in the dry period.