Types of Floods ( Shreeya ) (Coastal Floods (Strong winds generate large…
Types of Floods ( Shreeya )
Strong winds generate large waves known as storm surges.
bring out higher water levels and cause coastal floods.
Coastal floods can also be caused by tsunamis.
Caused by intense storms such as tropical storms and tropical cyclones. Tropical cyclones : typhoons and hurricanes.
Occur in areas along the coast.
Occur when the volume of water in a river channel increases beyond the capacity of the channel.
Water thus overflows the riverbanks and onto the floodplain, which refers to the low-lying land on either side of the river channel which are also known as leeves.
Possible causes of river floods are snow melt, heavy rainfall and dam failure.
Occurs suddenly and lasts for a short period of time.
Can be caused by river fall or coastal and river floods.
Can be recognised by the quick rise in water level.
Causes of Floods
refers to the droplets of water that falls to the ground.
condensation of atmospheric water vapour leads to formation of water droplets which form clouds
if the water droplets become too heavy, they fall as rain.
rainfall intensity, duration and frequency are characteristics of rainfall. the greater the rainfall intensity, duration and frequency, the greater the chance of a flood event occurring in a particular area.
rainfall intensity : rate at which rain falls , rainfall duration : duration of rain event , rainfall frequency : number of times a certain amount of rain falls within a period of time
Failure of Man-Made Structures
failure of man-made structures such as dams and levees can result in floods
a dam is a barrier built across a river to retain and store water. besides generating hydropower, a dam also helps to regulate the amount of water flowing in a rive. a dam failure can be disastrous for people living downstream.
the surface runoff that results from melting snow
a sudden rise of sea level in which water is piled up against a coastline beyond normal high-tide conditions.