Scientific Definition
Difference Between Flood and Flash Flood
Elements/Components of Flood
Causes and Effects of Flood
Types/Kinds of Flood
What to do before, during and after Flood
4. SCIENTIFIC DEFINITION
A general and temporary condition of
partial or complete inundation of normally dry
land areas from overflow of inland or tidal
waters from the unusual and rapid accumulation
or runoff of surface waters from any source.
Flood is…
The covering of normally dry land by
water that has escaped or been released from
the normal confines of: any lake, or any river,
creek or other natural watercourse, whether or
not altered or modified; or any reservoir, canal
or dam.
6. FLOOD AND FLASH FLOOD
FLOOD
It is an event that occurs
AFTER 6 hours following
the end of the causative
event which result in
fatalities, injuries, and/or
significant damage to
property.
Flooding events usually
take longer to develop
and they usually occur
along or near larger
rivers. The duration of
flooding events may
extend longer that 24
hours, perhaps several
days.
FLASH FLOOD
It is an event that occurs
WITHIN 6 hours
following the end of the
causative event which
result in fatalities,
injuries, and/or
significant damage to
property.
Flash flooding events
develop rapidly and can
occur anywhere water
collects, especially areas
of steep terrain, and
water runoffs. Flash
floods rarely last more
than 12 hours.
8. FACTS!
The yellow river (Huang He) in
China had the four deadliest flood
events in world history. The flood of
1931 resulted in 1 to 4 million people
being killed.
10. ELEMENTS/COMPONENTS
• Overland Flow
It is the flow of water that occurs when excess
storm water, melt water, or other sources flows
over the Earth’s surface. This might occur
because soil is saturated to full capacity, because
rain arrives more quickly than soil can absorb it.
11. ELEMENTS/COMPONENTS
• Inter Flow
It is the lateral movement of water in the
unsaturated zone that first returns to the surface
and enters a stream prior to becoming
groundwater. It occurs when water infiltrates into
the subsurface, hydraulic conductivity decreases
with depth, and lateral flow proceeds down slope.
16. CAUSES
Heavy Rainfall
Each time there are more rains than the drainage
system can, there can be floods.
River Overflow
If there is more water upstream than usual, and as it
flows downstream to the adjacent low-lying areas, there is a
burst and water gets into the land.
17. CAUSES
Strong Winds in Coastal Areas
Sea water can be carried by massive winds and
hurricanes onto dry coastal lands and cause flooding. Water
from the sea resulting from a tsunami can flow inland to cause
damage.
Dam Breaking
Too much water held up in the dam can cause it to
break and overflow the area. Excess water can be also
intentionally released from the dam to prevent it from
breaking and that can also cause flood.
18. CAUSES
Other factors:
Volume, spatial distribution, intensity and duration of rainfall
over a catchment.
Capacity of the watercourse or stream network to convey
runoff.
Catchment and weather conditions prior to a rainfall event.
Ground cover.
Topography.
Tidal Influences.
19. FACTS!
The Big Thompson Flood in
Colorado in 1976, killed 140 people.
95% of those killed in this flash flood
tried to outrun the waters along their
path rather than climbing rocks or going
uphill to higher grounds.
21. EFFECTS
Tangible Intangible
Direct
Damage to houses,
schools, factories,
roads, bridges,
furniture, cars,
machinery, power
plants, water supply.
Loss of life, health
effects, loss of
ecological value.
Indirect
Loss of industrial
production, traffic
disruption, loss of
customers.
Inconveniences of
recovery after flood,
increased vulnerability
of survivors.
22. EFFECTS
Economic
During floods (especially flash floods), roads, bridges,
farms, houses and automobiles are destroyed. People
become homeless. Additionally, the government deploys
firemen, police and other emergency apparatuses to help
the affected. All these come at a heavy cost to people and
the government. It usually takes years for affected
communities to be re-built and business to come back to
normalcy.
23. EFFECTS
Environment
Chemicals and other hazardous substances end up in the
water and eventually contaminate the water bodies that
floods end up in. In 2011, a huge tsunami hit Japan, and
sea water flooded a part of the coastline. The flooding
caused massive leakage in nuclear plants and has since
caused high radiation in that area. Authorities in Japan
fear that Fukushima radiation levels are 18 times higher
than even thought.
24. EFFECTS
People and Animals
Many people and animals have died in flash floods. Many
more are injured and others made homeless. Water
supply and electricity are disrupted and people struggle
and suffer as a result. In addition to this, flooding brings a
lot of diseases and infections including military fever,
pneumonic plague, dermatopathia and
dysentery. Sometimes insects and snakes make their
ways to the area and cause a lot of havoc.
25. EFFECTS
...But...
There is also something good about floods, especially
those that occur in floodplains and farm fields.
Floodwaters carry lots of nutrients that are deposited in
the plains. Farmers love such soils, as they are perfect for
cultivating some kinds of crops.
26. FACTS!
Just 6 inches of rapidly moving
flood water has the strength to knock a
person down.
28. TYPES/KINDS
COASTAL (SURGE FLOOD)
A coastal flood occurs in areas that lie on
the coast of the sea, ocean, or other large body of
open water. It is the result of extreme tidal
conditions caused by severe rain weather. Storm
surge is the leading cause of coastal. In this type
of flood, water overwhelms low-lying land and
often causes devastating loss of life and property.
30. TYPES/KINDS
FLUVIAL (RIVER FLOOD)
Fluvial flood occurs when excessive rainfall
over an extended period of time causes a river to
exceed its capacity. The damage from a river
flood can be widespread as the overflow affects
smaller rivers downstream, often causes dams
and dikes to break and swamp nearby areas.
32. TYPES/KINDS
PLUVIAL (SURFACE FLOOD)
Pluvial flood is caused when heavy rainfall
creates a flood independent of an overflowing
water body. This happen in any urban area – even
higher elevation areas that lie above coastal and
river floodplains. It can cause significant property
damage.
36. PHILIPPINE SITUATIONER
The recent flood happened in Philippines is the flood
hit in Misamis Oriental last January 17. Heavy rain was a
result of the tail-end of a cold front and low pressure area
has caused deadly floods have in Eastern Visayas and
Northern Mindanao, Philippines. Over 13,000 people have
been displaced from their homes. displaced from their
homes. Philippines News Agency (PNA) reports that at least
4 people have died in the floods in Cagayan De Oro City,
Misamis Oriental,
RECENT HAPPENING
37. Flooding in Visayas and Mindanao, January
2017
• FloodList reported that, as of 17 January, 4 people had
died and over 13,000 people had been displaced from
their homes. Cagayan de Oro City, in the province of
Misamis Oriental, received at least one month’s worth of
rain within 24 hours.
• On 22 January, a second Low Pressure Area (LPA)
entered the Philippines. Heavy rain once again resulted
in severe flooding to parts of Mindanao, especially the
provinces of Agusan del Sur and Compostela Valley.
38. A third LPA followed on 27 January bringing
further heavy rainfall to Mindanao as it
interacted with the tail-end of a cold front. The
Caraga Region was one of the worst affected
areas.
A recent report by the International Federation
of Red Cross And Red Crescent Societies (IFRC)
says that there were 9 deaths in total. The
flooding had damaged more than 1,300 homes
and displaced at least 334,000 people. A total of
586 houses in the towns of La Paz and Trento
(Agusan del Sur province) were damaged.
42. MOST PRONE PROVINCES IN THE PHILIPPINES
1. Pampanga
2. Nueva Ecija
3. Pangasinan
4. Tarlac
5. Maguindanao
6. Bulacan
7. Metro Manila
8. North Cotabato
9. Oriental Mindoro
10. Ilocos Norte
43. IT IS A DISASTER IF WE ARE NOT
PREPARED. – Loren Legarda
“Bes, kailangan mo maging preparado sa ano mang
pagsubok madadaanan mo. Huwang mong hintayin na
magsisi ka sa huli! – Payong kaibigan lang!”
45. WHAT TO DO BEFORE, DURING ANG AFTER
BEFORE FLOOD
Assemble disaster
supplies.
Be prepared to
evacuate.
46. WHAT TO DO BEFORE, DURING ANG AFTER
BEFORE FLOOD
Review your Family
Disaster Plan.
Protect your property.
47. WHAT TO DO BEFORE, DURING ANG AFTER
DURING FLOOD
Be alert.
Don’t drive unless you
have to.
48. WHAT TO DO BEFORE, DURING ANG AFTER
DURING FLOOD
Get to high ground.
Evacuate immediately if you think you
are at risk or are advised to do so.
49. WHAT TO DO BEFORE, DURING ANG AFTER
DURING FLOOD
Never try to walk or
swim through flowing
water.
Shut off the electricity
at the circuit breakers.
50. WHAT TO DO BEFORE, DURING ANG AFTER
AFTER FLOOD
Wait until it is safe
to return.
Travel with care.
51. WHAT TO DO BEFORE, DURING ANG AFTER
AFTER FLOOD
If a building was flooded,
check for safety before
entering.
Use extreme caution when
entering buildings.
52. WHAT TO DO BEFORE, DURING ANG AFTER
AFTER FLOOD
Take pictures of the damage.
Get professional help.
53. WHAT TO DO BEFORE, DURING ANG AFTER
AFTER FLOOD
Your home is no longer a safe
place.
When making repairs, protect your
property from future flood damage.
FURTHER EXPLANATION BASED ON LOREN LEGARDA DOCUMENTARY
Direct consequences happen at the time of the floods. Indirect occur later, after the floodwater has gone. Tangible damages can be directly calculated by their economic value. Intangible damages do not have a monetary value.
Direct consequences happen at the time of the floods. Indirect occur later, after the floodwater has gone. Tangible damages can be directly calculated by their economic value. Intangible damages do not have a monetary value.
Direct consequences happen at the time of the floods. Indirect occur later, after the floodwater has gone. Tangible damages can be directly calculated by their economic value. Intangible damages do not have a monetary value.
