Flash Floods and Their Management

Recently, flash floods in Orissa, Madhya Pradesh and other states have caused devastation of life and property, which is an annual problem in the region. However, flash floods are not restricted to these Indian states, rather it affects many other areas in the country.

Apart from natural factors like incessant and heavy rainfall during the monsoon, there are man-made factors that contribute to flash floods in India.

India is highly vulnerable, as most of its geographical area is prone to annual flooding. The high losses and damages due to flash floods show the poor adaptation and mitigation status of India and inadequacy in disaster management and preparedness. Thus, there is a need for an Integrated flood management system.

What are Flash Floods?

Excessive or continuous rainfall over a number of days or during specific seasons can create water stagnation and floods. Flash floods are similar to this, but occur in a much shorter period of time.

Flash floods occur in both rural and urban regions. When there is more rainfall than the ground can absorb, or when it falls in locations with a lot of impervious surfaces like concrete and asphalt that hinder the ground from absorbing the precipitation, the water has few places to go and can rise quickly. Flash flooding commonly happens more where rivers are narrow and steep, so they flow more quickly. They can occur in urban areas located near small rivers, since hard surfaces such as roads and concrete do not allow the water to absorb into the ground.

In India, flash floods are often associated with cloudbursts – sudden, intense rainfall in a short period of time. Himalayan states further face the challenge of overflowing glacial lakes, formed due to the melting of glaciers, and their numbers have been increasing in the last few years.

Why are flash floods likely to become more common in India in the coming years?

According to government data from the Assam State Disaster Management Authority, India is the world’s second worst flood-affected country after Bangladesh, accounting for one-fifth of all flood-related deaths. Flash floods are widespread in places such as Chennai and Mumbai. Flash floods are also caused by depressions and cyclonic storms in coastal portions of Orissa, West Bengal, Andhra Pradesh, and other states.

One of the causes for the frequency of floods, according to data from the National Disaster Management Authority, is that nearly 75% of all Indian rainfall is concentrated during a four-month monsoon season (June to September). As a result, river discharge is high throughout these months. Floods threaten about 40 million hectares of land in the country, with 18.6 million hectares of land affected on average each year.

Flash floods may become more common in the future as a result of the increased frequency of wildfires. This is because wildfires kill forests and other vegetation, weakening the soil and making it less permeable to water.

Flash Floods Management

Despite significant investments and ongoing flood-control measures in India, socioeconomic devastation and the mortality toll remain severe. The flood management process in India is undoubtedly complex due to the influence of numerous socio-hydro climatological factors such as climate change, sea level rise, and socio-economic dynamics.

• The key characteristics of flash floods that should be taken into consideration when a management strategy is developed are: the assessment of the place, local scale of the event, and particularly the magnitude of the phenomenon, as well as the very short response time and the great threat to human lives.

• Flash flood protection measures can be categorized as structural and non.structural. These measures can complement each other, so it may be appropriate to consider both when evaluating a flash flood management approach. Although the typical structural measures, like the building of retention reservoirs and embankments, cannot always be adopted in areas susceptible to flash floods, small scale structural measures supplemented by non.structural measures can play an essential role in delaying the flow of water, allowing it to be locally retained, or diverting it from places where it could pose a threat to people or properties.

• Flood forecasting and warning can play important roles in reducing exposure caused by flash floods. The goal of a flash flood forecast approach is to provide timely and accurate information and data for the development of warnings to save lives (primarily) and property.

• The effectiveness of the measures to reduce vulnerabilities can be ensured by properly assessing vulnerability and identifying the underlying factors contributing to it. The efficiency of a warning and response system depends on the level of the awareness at the local level.

• Where applicable, flash flood management needs to address several sector.specific areas of public law. In particular – disaster preparedness and mitigation, as well as natural resources management. Though the applicability of various laws and regulations must be evaluated on a case.by.case basis, they can provide a number of crucial functions in implementing government policies.

• The best way to stay safe in a flash flood is to be aware of the danger and be ready to respond. Low-lying areas are at risk of flooding, whether it happens slowly or quickly and whether it’s an urban or rural setting.