Flood disaster ppt it's about natural environment

Flood disaster

1. NATURAL DISASTER Name: Arya Reg no. :21101141049 Roll no. : 21CV82 4th sem ,2nd year Civil Engineering #PROF. : AMIT KUMAR

2. introduction A Natural disaster is defined as: A major event brought about the natural processes of the earth causes widespread destruction to the environment and loss of life. Natural Disasters are catastrophic events that result from any of the Earth’s natural phenomena. These can range from floods and hurricanes to tsunamis and earthquakes. Natural disasters often cause destruction on a massive scale. Certain natural disasters such as wildfires cause destruction of animal habitat as well as damage to property and loss of life.

3. Types of natural disaster Floods Landslides Volcanic eruptions Earthquakes Hurricanes Tornadoes Blizzards Tsunami Cyclones Wildfires Pandemics

4. FLOODS A flood is an overflow of water on land. Sometimes a river might receive extra water, either from heavy rains or other natural disasters. When this happens, the water overflows from its normal path in the River bed and onto the dry land. Floods can happen during heavy rains, when ocean waves come on shore, when snow melts quickly or when dams or levees break. Damaging flooding may happen with only a few inches of water, or it may cover a house to the rooftop. Floods can occur within minutes or over a long period, and may last days, weeks, or longer. Floods are the most common and widespread of all weather-related natural disasters .

5. Types of floods Flash floods Coastal floods. Urban floods. River (or fluvial) floods. Ponding (or pluvial flooding)

6. FLASH FLOOD A flash flood is a rapid rise of water along a stream or low-lying urban area. Flash flooding occurs within six hours of a significant rain event and is usually caused by intense storms that produce heavy rainfall in a short amount of time.

7. COASTAL FLOOD Coastal flooding  occurs when dry and low-lying land is submerged ( flooded ) by  seawater .  The range of a coastal  flooding  is a result of the elevation of floodwater that penetrates the inland which is controlled by the  topography  of the coastal land exposed to flooding The seawater can flood the land via several different paths: direct flooding, overtopping of a barrier, or breaching of a barrier. Coastal flooding is largely a natural event. Due to the  effects of climate change  (e.g.  sea level rise  and an increase in  extreme weather  events) and an increase in the population living in coastal areas, the damage caused by coastal flood events has intensified and more people are being affected

8. URBAN FLOOD Urban flooding is significantly different from rural flooding as urbanization leads to developed catchments, which increases the flood peaks from 1.8 to 8 times and flood volumes by up to 6 times. Urban areas are densely populated and people living in vulnerable areas suffer due to flooding, sometimes resulting in loss of life. It is not only the event of flooding but the secondary effect of exposure to infection also has its toll in terms of human suffering, loss of livelihood and, in extreme cases, loss of life. Urban areas are also centres of economic activities with vital infrastructure which needs to be protected 24x7. In most of the cities, damage to vital infrastructure has a bearing not only for the state and the country but it could even have global implications. Major cities in India have witnessed loss of life and property, disruption in transport and power and incidence of epidemics. Therefore, management of urban flooding has to be accorded top priority.

9. RIVER FLOOD A river flood occurs when a river overspills its banks; that is, when its flow can no longer be contained within its channel. Flooding is a natural and regular reality for many rivers, helping sculpt soil and spread nutrients in alluvial valleys and supporting many ecosystems – such as swamps and bottomland forests – adapted to occasional inundation. River floods have also been life-giving forces for human societies dependent on them for agriculture and soil fertility. Nonetheless, humans often perceive floods negatively because of the damage and loss of life they often wreak where natural floodways have become heavily developed and populate

10. CAUSES OF FLOOD

11. HISTORY OF FLOOD In June 2013, Uttarakhand experienced one of the worst floods in recent Indian history. Heavy rain caused by a cloudburst caused flash floods and landslides in northern Uttarakhand . Millions of Hindu pilgrims visit the state each June to pay their respects at the old temples. The rains took everyone off guard because they fell a full month before the monsoon season. Hemkund , Kedarnath , Badrinath, Valley of Flowers, Roopkund , and Rudraprayag were among the Uttarakhand locations hit. While the military was able to remove over 100,000 persons trapped in landslides, an estimated 4,094 were murdered and over 5,700 were missing (and were later assumed dead).

12. PREVENTION FROM FLOOD Humans cannot stop the rains from falling or stop flowing surface water from bursting its banks. These are natural events, but we can do something to prevent them from having a great impact. Here are a few Sea / Coastal Defence Walls Sea walls and tide gates have been built in some places to prevent tidal waves from pushing the waters up ashore. In some areas too, sandbags are made and placed in strategic areas to retain floodwaters

13. Retaining walls In some places, retaining walls levees, lakes, dams, reservoirs, or retention ponds have been constructed to hold extra water during times of flooding. Town planning Builders must acquire permission before buildings are erected. That will ensure that waterways are not blocked. Also, drainage systems must be covered and kept free from objects that chock them. This way, water can quickly run through if it rains and minimizes any chance of town flooding. Drainage systems should also be covered to prevent litter from getting into them . Vegetation Trees, shrubs, and grass help protect the land from erosion by moving water. People in low-lying areas must be encouraged to use a lot of vegetation to help break the power of moving flood water and also help reduce erosion. Education In many developing countries, drainage systems are chocked with litter and people have little knowledge of the effects that can have during rain. When it rains, waterways and culverts are blocked by massive chunks of litter and debris, and water finds its way into the streets and people’s homes. Education is therefore very important, to inform and caution people about the dangers of floods, what causes floods, and what can be done to minimize its impact .

14. Fig: Some Flooded Area

15. MAP OF FLOODED AREA IN INDIA