Presented By:- : Presented By:- Sagar Jhunjhunwala
Vedang Bamnote Introduction : Introduction Floods are temporary inundation of large regions as a result of an increase in reservoirs or of rivers flooding their banks .
A flood is an overflow of an expanse of water that submerges land. Introduction : Introduction Floods often cause damage to homes and businesses if they are placed in natural flood plains of rivers.
People have lived and worked by the water to seek sustenance and capitalize on the gains of cheap and easy travel and commerce by being near water so humans are mostly affected by floods. Causes of flood : Causes of flood Slide 7: The most common type of floods is caused when the river owerflows its banks and water spreads on the surrounding land.
Floods can also be caused due to following factors :- Blocking of river channel landslide : Blocking of river channel landslide Strong tides and storms in the sea : Strong tides and storms in the sea Cyclones and tsunamis over the water bodies : Cyclones and tsunamis over the water bodies Change in the course of a river : Change in the course of a river Wrong design of a dam, or a canal : Wrong design of a dam, or a canal Deforestation : Deforestation Types of floods : Types of floods Flooding can be divided into different categories according to their duration:
Flash Floods Slow-Onset Floods : Slow-Onset Floods Slow-Onset Floods usually last for a relatively longer period, it may last for one or more weeks, or even months. As this kind of flood last for a long period, it can lead to lose of stock, damage to agricultural products, roads and rail links. Rapid-Onset Floods : Rapid-Onset Floods last for a relatively shorter period, they usually last for one or two days only.
Although this kind of flood lasts for a shorter period, it can cause more damages and pose a greater risk to life and property as people usually have less time to take preventative action during rapid-onset floods. Rapid-Onset Floods Flash Floods : Flash Floods Flash Floods may occur within minutes or a few hours after heavy rainfall, tropical storm, failure of dams or levees or releases of ice jams.
It causes the greatest damages to society. Flooding can also be divided into different categories according to their location: : Coastal Floods
Urban Floods Flooding can also be divided into different categories according to their location: Coastal Floods : Coastal Floods Coastal Floods usually occur along coastal areas. When there are hurricanes and tropical storms which will produce heavy rains, or giant tidal waves created by volcanoes or earthquakes, ocean water may be driven onto the coastal areas and cause coastal floods. Arroyos Floods : Arroyos Floods A arroyo is river which is normally dry. When there are storms approaching these areas, fast-moving river will normally form along the gully and cause damages. River Floods : This is the most common type of flooding. When the actual amount of river flow is larger than the amount that the channel can hold, river will overflow its banks and flood the areas alongside the river. And this may cause by reasons like snow melt or heavy spring rain. River Floods Urban Floods : In most of the urban area, roads are usually paved. With heavy rain, the large amount of rain water cannot be absorbed into the ground and leads to urban floods. Urban Floods Flood prone areas : Flood prone areas Low lying parts of active flood plains and river Esturies : These areas suffer the most from floods.
In Bangladesh, 110 million people live unprotected on the flood plains of southern Asia’s most flood prone river system.
Flood generally affect more than 30% of the total land area in Bangladesh. Low lying parts of active flood plains and river Esturies Small Basins : They are subjects to flash floods. These also occur in narrow valleys and heavily developed urban settings with rapid run off. Small Basins Areas below unsafe dams : Floods resulting from failures are examples of combined natural and technological hazards.
As they are prone to flash floods, opportunities for warning evacuation are limited. Areas below unsafe dams The Indian Experience : The Indian Experience India experiences more floods than any other country.
About one-eighth of the total area of the country is prone to floods.
Floods damage the standing crops and take a heavy toll of life and property. Flood Forcasting : Flood Forcasting This involves giving prior information regarding floods.
This is essential so that timely action can be taken to prevent loss of life. Flood Forcasting : Flood Forcasting The flood forecasting techniques are constantly reviewed, updated and modernized to make forecasts more accurate.
This will reduce the miseries suffered by the people from recurring floods. Precautions against floods : Precautions against floods First-aid kit should be kept ready.
Radio, torch, candles and spare batteries . . shouud be kept at stock.
Cattle should be removed to higher places. Precautions against floods : Precautions against floods Adequate stock of fresh water, dry food articles, salt, sugar and kerosene should be kept handy.
In case of floods, power should be turned-off and all electrical appliances should be disconnected.
Only boiled water should be consumed and only freshly cook food should be eaten. Precautions against floods : Precautions against floods Medicines for snake bites and diarrhoea should be kept at stock.
Listen to radio or keep in touch with television for warning and advises Conclusion : Conclusion Floods take a heavy toll of life and property so necessary precautions should be taken.
Floods are great fury of nature and humans can take precautions against it but can not control it.