Image Credits - World Atlas
A flood occurs when there is an excess of water on land, often due to factors such as heavy rainfall or other natural calamities. In such instances, rivers may receive more water than they can contain within their normal boundaries, causing the water to spill over onto adjacent dry land areas. Let us look at the various factors that cause floods in depth.
Major causes of floods in India
Meteorological Factors
1. Heavy Rainfall: Monsoon season in India typically spans from mid-July to the end of September, bringing heavy rainfall that fills dams. When the accumulated water surpasses storage capacity, flooding occurs. Regions prone to rainfall-induced floods include the sub-Himalayan plains of West Bengal, the Indo-Gangetic plains, the Western Ghats’ west coast, and Assam.
2. Cloud Burst: Intense precipitation within a short timeframe, often accompanied by hail and storms, can trigger cloud bursts. These events primarily occur on mountain slopes, with water flowing downhill to the plains, causing floods.
3. Cyclones: Cyclones form in low-pressure areas where winds circulate inwardly, often accompanied by severe storms. Eastern coastal states like Tamil Nadu, West Bengal, Odisha, and Andhra Pradesh are particularly susceptible to cyclonic floods.
4. Global Warming: High global temperatures have triggered the melting of glaciers and ice sheets, resulting in a rise in sea levels. This phenomenon poses a heightened risk of flooding to coastal regions worldwide. Specifically, the melting of Himalayan glaciers due to rising temperatures has led to an increase in sea levels, exacerbating the flooding risk in surrounding areas. As sea levels continue to rise, coastal communities face greater vulnerability to inundation and coastal erosion, highlighting the urgent need for comprehensive measures to mitigate the impacts of climate change on coastal regions.
5. Earthquakes and Landslides: Tectonic plate shifts can alter surface water volume and course, posing flood risks. Landslides also elevate river sediment levels, increasing the risk of flooding.
Physical Factors
1. Inadequate Drainage Management: Numerous cities across India are equipped with outdated or inadequate drainage systems, incapable of coping with heavy rainfall. Consequently, this inadequacy leads to waterlogging and eventual flooding. When drainage systems are poorly designed, they fail to effectively manage excess water during intense rainfall events, resulting in the accumulation of water and subsequent flooding. This not only disrupts daily life and infrastructure but also poses significant risks to public safety and health.
2. Catchment Area: The catchment area, which includes lakes or reservoirs from where rainfall water drains into rivers, can contribute to flooding. During monsoon seasons, if the amount of water exceeds the capacity of the catchment area, flooding can occur.
Human Factors
1. Siltation: Siltation is a form of water pollution resulting from the accumulation of terrestrial clastic material, primarily consisting of silt or clay particles. This phenomenon involves both the heightened presence of suspended sediments in water and the buildup of fine sediments on surfaces like riverbeds, which is considered undesirable.
Siltation occurs when silt and sediments accumulate in riverbeds, disrupting the natural flow of rivers and contributing to flooding.
2. Poor Agricultural Practices: Certain upland farmers contribute to soil and water runoff into rivers by leaving fields bare and compacting the land through cattle grazing and heavy machinery use. When agricultural waste is not managed properly or disposed of in rivers, it can exacerbate flooding risks. This occurs when excess water-carrying soil and debris flows into rivers, potentially leading to increased water levels and flooding downstream. In essence, inadequate agricultural practices can directly impact the hydrological cycle, disrupting natural water flow patterns and increasing the likelihood of floods.
3. Deforestation: Deforestation significantly increases the risk of flooding by removing trees that absorb water and stabilize soil. Without trees, more water runs off into rivers during heavy rainfall, exacerbating flood potential. As tree populations decline, there is a buildup of carbon dioxide in the atmosphere. Elevated levels of carbon dioxide act as a greenhouse gas, trapping heat from the sun and leading to a rise in temperatures. Consequently, increased rainfall leads to water accumulation on the Earth’s surface, contributing to the occurrence of floods
4. Dam Failures: Dams, while constructed to store water and regulate flow, can fail due to wear and tear or collapse under extreme conditions. Additionally, the release of water from dams during prolonged heavy rainfall can contribute to flooding. Throughout history, numerous instances of dam failures have resulted in extensive property damage as floodwaters inundate infrastructure. Furthermore, ecosystems and habitats suffer destruction from flooding. Additionally, dam failures have claimed thousands of lives over the years.
Addressing these multifaceted challenges requires comprehensive measures, including improved infrastructure, sustainable land use practices, and effective disaster management strategies. By addressing these factors holistically, India can mitigate the impacts of floods and enhance resilience to future extreme weather events.
This article has been modified using Artificial Intelligence (AI) tools.
