When a large –scale accident affects man and nature, we call it a disaster. This can occur without a warning. Natural disasters include floods, droughts, earthquakes, tsunamis, volcanic eruptions and landslides.
Massive earthquakes hit Latur district of Maharashtra and Bhuj in Gujarat in the last few years. The latest earthquake to rock our part of the world was in 2005-2006. Jammu and Kashmir in our country and parts of Pakistan were badly affected by this earthquake. The loss due to an earthquake is unimaginable in terms of intensity and area.
When an earthquake occurs in the sea, it raises huge, destructive waves called tsunami. In 2004, Andaman and Nicobar islands, Tamil Nadu and Andhra Pradesh, were devastated by a tsunami that caused widespread destruction in Indonesia and reached almost up to Africa.
Famines are a result of consistently less than average rainfall resulting in continuous droughts in an area. The effects of a drought are measured in terms of the ability of an area to hold and retain water. Conservation of water in reservoirs, lakes and as groundwater will reduce the intensity of a drought. Our country has been facing drought conditions continuously for the last few years.
On the other hand, cyclones have affected Orissa. Andhra Pradesh and Gujarat causing heavy losses in terms of lose of lives and damage to property. During heavy rain fall, rivers, lakes and other water bodies overflow being unable to hold the incoming water. This causes flooding not only in the surrounding areas but also in downstream region. Low-lying costal areas are also affected by floods.
As for those living on hillsides, landslides during rainy season are common. They cause heavy loss of lives and of houses and property. Landslides are common in Jammu and Kashmir, Uttaranchal, and Himachal Pradesh and in the hilly regions of the north-Eastern states.
In the river valleys and on the mountains, large scale road laying activity is being carried out uprooting trees and digging up to hillsides. This disturbs the rocks in the area and loosens the sand, which may cause landslides, especially during the rains, in 2004, when the Tehri dam was being built; a tunnel collapsed killing twenty four people. Landslides on to roads have killed hundred of travelers. We know that these landslides occur on the road to Tirumala. In the same way, the Eastern Ghats, the Nallamalla hills and the Paapikonda hills have roads that are prone to landslides.
Sometimes a big mass of ice breaks off the face a mountain. This is called an avalanche. When the molten water from the avalanche is released suddenly there is a flood. These are common in the Himalayas.
Every year, floods have become common in some parts of the country. Swollen with rain water, rivers flood the low- lying areas. Fields and houses are submerged totally in water. Floods cause terrible loss of life and property. This is followed by shortages of drinking water and food. Epidemics spread in the area too. India, with a flood –prone area of 2.5 crore hectares, suffers such floods and resultant tragedies frequently. An average of 75 lakh hectares of land actually suffers from floods every year. The main reason for floods is our inability to store water when it rains.
On the other hand, due to building of houses, especially in our cities, in a way that obstructs the flow of water, artificial flooding is frequently affecting our cities. Encroachment over canals carrying rain water and lake and riverbeds has been obstructing the flow of rainwater. Apart from this discarding of plastic everywhere blocks the flow of rain water. Apart from this discarding of plastic everywhere blocks the flow of rainwater. This causes artificial flooding. This happened in 2005 in Chennai, Bangalore, Mumbai and Hyderabad.
In the upper reaches of our rivers, large scale deforestation is causing large scale soil erosion. Due to this, soil from the deforested area in the mountains flows down with rain water and reaches the rivers and fills the river course party. As a result, the water overflows the bank of the rivers, resulting in floods and inundating the low- lying areas.
Over –grazing of cattle by people on the slopes of mountains where growth of grass is quite less soil erosion occurs. Besides, lack of green cover over such areas leads to flooding of the plains.
In our north- eastern states, slash and burn agriculture has also caused erosion with similar consequences. Erosion has worsened the effects of floods in the Brahmaputra basin.
In our country, 60% of the flooding happens due to overflowing of rivers, and the remaining 40% due to heavy rains and cyclones.
The poor drainage system in states like Rajasthan, Punjab and Haryana is also causing floods due to which the agricultural fields are regularly submerged.
The Himalayan rivers of the Indus, Ganges, Brahmaputra and others swell up with rainwater and floods parts of Haryana, Punjab, Uttar Pradesh, Bihar and west Bengal. The Brahmaputra destroys many regions in Assam and Bihar every year. The coastal areas in Orissa, Andhra Pradesh and Tamil Nadu are regularly battered by cyclones. Nightmarish memories of some disasters like the Gujarat cyclone, the Diviseema cyclone, and the Orissa cyclone haunt people years after their occurrence for the destruction caused by them.