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Why are flash floods increasing in India? Is it possible to avoid the wrath of this natural disaster?

With the increase in formation of glacial lakes, the chances of flash floods are increasing.

Rapid climate change has had severe impacts in India. With the rise in the average global temperatures, a worrying trend has developed characterized by no rain for extended periods and then a sudden session of an extreme downpour. These sudden rainfalls have led to extreme climatic events, especially floods that destroyed livelihoods, agricultural lands, consumed human life and thereby resulted in huge losses in revenue.

Climate change and India: A 4X4 assessment a sectoral and regional analysis for 2030s floods report

Temperature rise in India would increase the frequency of flood events in India during the end of the 21st century (2071-2100). The Himalayan belt is projected to witness a remarkable rise in temperature up to 2.6 degrees Celsius and also by the 2030s the intensity is expected to increase by 2-12 per cent. The report further stated this will result in the multiplication of flash flood incidents leading to extensive landslides, which would bring extreme damage to the agricultural area thereby threatening the food security of the country.

Monday’s flash flood incident in Himachal Pradesh, India is just another indication of the perils that the Himalayan states like Himachal Pradesh and Uttarakhand faces from environmental processes like cloudbursts, avalanches, lake bursts and landslides. As the country witnessed in 2013 in Uttarakhand, India such natural processes are capable of activating much larger disasters and cause havoc destruction. But is it possible to reduce the intensity of such natural disasters? According to scientists, though the whole natural process cannot be stopped, some measures can be followed by mankind to reduce the threats of such destructive events.

mapping climate change in india

Increasing the number of glacial lakes

Outside of the Polar Regions, the glaciers serve as the largest source of fresh water. Snowmelt and glaciers in the mighty Himalayan region are the sources of water for the various rivers throughout the subcontinent. These sources are in charge of maintaining the perpetual flow of water in India like the Bramhaputra, Indus and the Ganges. More than a billion people’s lives are dependent on these rivers and they serve as the lifelines of India.

With the increase in the global average temperature in India, these glaciers have been progressively shrinking in mass and surface area. Scientists believe that the shrinking of glaciers can be traced back to the time of the little ice age (start date 1303). After 1850, the world started witnessing an increase in global temperature. The rise picked up gradually and more swiftly in the 20th century as a result of the increasing levels of greenhouse gases. The graph took a sharp inclination since the 1980s.

Some research projects that the outcome of an elevation in global temperatures by 2 degrees Celsius from 1850 to 2070 would be the total disappearance of 45 per cent of the large and medium glaciers. It is also estimated that almost 70 per cent of the smaller glaciers would melt away with the global temperature rising by 2 degrees Celsius. As a result of diminishing glaciers, several glacial lakes have formed all through the Himalayas. A significant number of these high-altitude glacial lakes pose a potential risk, due to their capability of causing flash floods in the event of a lake burst.

Several newspapers and science journals have pointed out that there has been a significant increase in the number of glacial lakes in the past few decades because of the speedy melting of the glaciers. According to a study in 2005 by the Kathmandu-based International Centre for Integrated Mountain Development (ICIMOD), 127 such glacial lakes have been listed in Uttarakhand, India. More recently, the numbers have increased and the state now consists of around 400 glacial lakes. According to glaciologists, the numbers are quite stressful and pose a serious challenge.

uttarakhand's furious himalayan flood could bury india's hydropower program - circle of blue

Tracking

To manage the potential risks from these lakes, the first step needed to be taken is tracking the growth of glacial lakes more regularly and actively. According to experts, it is not necessary to track every glacier. Generally, glaciers in a particular basin do not have significantly separate properties. So, if the authorities can distinguish one or two standard glaciers in every basin which are less difficult to be accessed, and study the details, then the analysis can be concluded to the other glaciers in that basin or the state.

But being dependent on remote sensing and satellites may not give fruitful results. For accurate results, the job demands on-field monitoring by people and measuring devices. This is the reason why the chosen glacier should be in an accessible position. For effective outputs, glaciologists need to monitor the bathymetric changes, discharge balance, expansion mechanisms, water level fluctuations, mass balance, and other such geological features. This sort of monitoring demands a lot of manpower and economic strength and requires a fruitful utilization of these resources.

For decision making of any sort, a systemic dataset that monitors the continuous changes in India is vital. Some amount of tracking and scrutinizing is already happening but it is scattered. What is needed is a compact state of glaciers in India, with the propensity to zoom in on them and monitor the conversions taking place every year. According to the well-known glaciologist Mr Syed Iqbal Hasnain, the Himalayan states themselves should take the lead in this task. He also suggests that the respective state governments should not rely on outside agencies for tracking or data.

Planning a framework

In 2020, the glacial burst in the Chamoli district of Uttarakhand in India is an example of the imbalance in ecological processes caused by human activities. The Himalayas are a young and unstable chain of mountain ranges. Even the slightest change in the adjustment of rocks may trigger devastating landslides. Despite these factors, frequent mountain blasting, stone quarrying, construction of hotels, roads, digging tunnels and construction of dams are continuing in the vulnerable Himalayan belt.

Construction-related activities might not serve a direct connection to the increase of flash floods, but at the same time, these cannot be ignored completely. In every environmental assessment before starting an important project, glaciers must be included compulsorily. For example, before the construction of a dam, the environmental impact assessment report should include the dam’s estimated threat to the glaciers in that region. The assessment report should focus on the entire catchment area. It is also advised that the project holders must invest in such assessments because it is their own money that is also at risk.

Alleviation measures

Mr Syed Iqbal Hasnain further suggests that if the glaciers are kept under regular scrutiny, it would amplify the chances of recognizing the lakes that are in immediate need of mitigation. Many geotechnical and structural measures can be implemented, and several success stories where the potential risk of the glacial lakes have been diminished, are examples that prove these measures are helpful.

He also suggests that there is a possibility of constructing channels for slow and gentle discharge of water from such lakes, which will, in turn, reduce the stress on them, and limit the chances of rupture. Not only that, but this procedure also lessens the amount of water that gushes into the flash flood. Setting up alarm systems can also prove to be helpful. Alarm systems could be set up at the glacial lakes, which will immediately alert the human settlements downstream as soon as an overflow takes place. A preliminary retaliation drill needs to be worked out as well, similar to those drills done for tsunami and cyclones.

eye on calderdale - flood action plan infographics

If the mitigating measures are not taken seriously, and people do not start taking responsibility for such natural disasters, the time is not far away when our lives would be an exact scene from those sci-fi Hollywood movies showing the end of planet earth.

Edited by Tanish Sachdev

Sanjana Simlai

Hey, this Sanjana. Am from Kolkata. Reading, writing and travelling have always attracted me. I am always ready to learn and look forward to opportunities that would enhance my career in Journalism. I spend my free time in clicking pictures with my Nikon DSLR and I find solace in poetry.

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