What are the Effects of Flood?
A flood is an overflow or over-surge of water on land. The causes of floods are diverse and may range from heavy rainfall to tsunamis and other natural or artificial catastrophes. In simple terms, when a flood occurs, it results in an overflow of water on land that is otherwise dry. The phenomenon of a flood is studied explicitly under the subject of Hydrology. We have to remember that there are a few positive consequences along with the devastating effects of flood.
Before trying to answer the question – what are the effects of flood – let us try and explore the various kinds of floods first.
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Types of Floods
There are five main types of floods– river floods, coastal floods, storm surge, flash floods, and inland flooding.
River Flood- It is a type of flood that occurs when the water levels rise over the top of a riverbank. They happen across all rivers and streams.
Coastal Floods– We can understand coastal floods as the inundation of typically dryland areas and coastal lands with seawater. The various causes of coastal floods include tidal surges, high winds, barometric pressure, and so forth.
Storm Surge – It is the abnormal rise of water in coastal areas above the range of normal astronomical tide. Storm surge is a consequence of three factors – wind, waves, and barometric pressure.
Inland Flooding – Also known as urban floods, inland floods occur in a place's interior regions either due to heavy rainfall or improper drainage systems.
Flash Foods – We can understand a flash flood as an overflow of water that begins within three to six hours of intensely heavy downpour.
Now that we have talked about the various types of floods let us explore the causes and effects of floods.
Causes of Floods
Before going through the nuances of causes and effects of floods, let us begin by concentrating on the former.
Needless to say, a heavy and unstoppable downpour is the primary cause of floods. Heavy rains can damage the draining system and result in floods. Likewise, river overflow is another cause of flooding. It happens when the volume of water upstream is more than the usual amount, and it flows downwards to low-lying areas causing havoc on the drylands.
When discussing the causes of floods, we cannot ignore the impact of strong coastal winds on rivers. At times, massive amounts of seawater are carried onto dry coastal lands via strong winds. Similarly, the breaking and disruption of dams result in floods, as well. We can understand dams as man-made structures that hold the flow of river water from a highland area to a lowland. The power generated by the energy is utilized for various reasons. Unfortunately, the holding back of too much river water can cause the dam to break and cause floods.
Lastly, it is noteworthy to remember that the melting of snow caps also results in floods which are termed snowmelt floods. Having talked about the causes of floods, let us try to answer the question – what are the effects of floods – in apt detail.
Primary Effects of Flood
It is imperative to keep in mind that there are various negative effects of floods. Let us analyze those effects.
Devastation – Unfortunately, floods can destroy a place in a matter of hours. A combination of cloudburst and heavy downpour coupled with a populated area directly implicates massive devastation, life loss, and property loss. Floodwaters have intense strength and speed, and they are impossible to stop after the flow begins. As such, it is crucial to be vigilant and closely observe the local streams and rivers at all times.
Pollution – There are various after effects of flood and pollution are one of them. Floodwaters are barely clean, and they carry along with everything that comes in their way, such as debris, poisonous substances, and so forth. Thus, even when the floodwaters recede from an area, their impact remains for a long time.
Loss of Life and Property – Another significant negative impact of floods is the loss of precious lives and property. History has been witness to terrible floods that have resulted in substantial economic and personal losses.
Thus, we can analyze the causes and effects of floods in apt detail. If you are interested, you can also look at the effects of flood and drought together to better grasp the nitty-gritty of common natural disasters.
FAQs on Flood
1. What is a flood, and how is it defined in Geography?
In geography, a flood is defined as an overflow of a large amount of water beyond its normal limits, especially over what is normally dry land. It occurs when a river, lake, or ocean's water level rises and submerges the surrounding areas. This natural disaster is primarily characterised by the inundation of land that is not typically underwater, leading to significant environmental and societal impacts.
2. What are the primary causes of floods?
The primary causes of floods can be broadly categorised into natural and human-induced factors.
- Natural Causes: These include prolonged or heavy rainfall, rapid snowmelt in mountainous regions, storm surges in coastal areas caused by cyclones, and tsunamis.
- Human-Induced Causes: These include deforestation, which reduces the soil's ability to absorb water; urbanisation, which increases surface runoff due to concrete surfaces; poorly planned construction in floodplains; and the failure of man-made structures like dams and levees.
3. What are the different types of floods?
Floods are classified based on their cause, duration, and location. The main types are:
- Fluvial (River) Floods: Occur when a river's flow exceeds its channel's capacity.
- Pluvial (Surface) Floods: Caused by intense rainfall creating a flood event independent of an overflowing water body, common in urban areas.
- Coastal Floods: Result from high tides, storm surges, or tsunamis inundating coastal land.
- Flash Floods: Characterised by a rapid and extreme flow of high water, typically caused by intense rainfall over a short period.
4. How is urban flooding different from river flooding?
Urban flooding is different from river flooding primarily in its cause and location. River flooding occurs when a river overflows its banks due to excessive rainfall or snowmelt upstream. In contrast, urban flooding is the inundation of land in a densely populated, built-up area. It is often caused by intense, short-duration rainfall that overwhelms the capacity of drainage systems, a situation worsened by impermeable surfaces like roads and buildings that prevent water absorption into the ground.
5. How do human activities like deforestation and unplanned construction increase flood risk?
Human activities significantly worsen flood risk. Deforestation removes the tree canopy and root systems that intercept rainfall and help soil absorb water. This leads to increased and faster surface runoff into rivers, raising flood levels. Similarly, unplanned construction and urbanisation cover the ground with impermeable surfaces like concrete and asphalt. This prevents rainwater from seeping into the ground, forcing it into drainage systems that can quickly become overwhelmed, leading to severe flash floods in cities.
6. What are the major negative effects of a flood?
Floods have devastating negative effects on communities and the environment. The major impacts include:
- Loss of Life and Property: Drowning is a major risk, and floodwaters can destroy homes, buildings, and critical infrastructure like roads and bridges.
- Economic Disruption: Damage to crops, livestock, and businesses leads to significant economic losses and disrupts livelihoods.
- Health Crises: Contamination of water supplies can lead to the outbreak of water-borne diseases like cholera and typhoid.
- Environmental Damage: Floods can cause soil erosion, destroy habitats, and pollute rivers and land with debris and contaminants.
7. Are there any positive effects of floods?
While overwhelmingly destructive, natural, seasonal floods can have some positive effects, particularly in riverine ecosystems. Floodwaters carry and deposit nutrient-rich silt and sediments onto floodplains, which can improve soil fertility for agriculture. Floods also play a crucial role in recharging groundwater aquifers and maintaining the ecological health of wetlands, which are vital habitats for many species of flora and fauna.
8. Which regions in India are most prone to floods and why?
In India, the most flood-prone regions are the vast plains of the Ganga and Brahmaputra river basins. States like Bihar, West Bengal, Assam, and Uttar Pradesh are severely affected almost annually. This is due to heavy monsoon rainfall, sediment deposition that raises riverbeds, and snowmelt from the Himalayas. Coastal states like Odisha, Andhra Pradesh, and Gujarat are also vulnerable to flooding from cyclones and storm surges.
9. Why are flash floods often considered more dangerous than other types of floods?
Flash floods are considered more dangerous primarily due to their speed and lack of warning time. They develop very quickly, often in minutes or a few hours, following intense rainfall, leaving little to no time for evacuation. The water moves at a very high velocity, carrying large debris like boulders and trees, which gives it immense destructive power capable of sweeping away people, vehicles, and even buildings instantly.
