Floods 2

[email protected] "The only thing that stops God from sending another flood is that the first one was useless". - Nicholas Chamfort (1741 - 1794) Ju/09

Prevention

Preparedness (Warning)

Relief

Earthquakes

Mapping geological lineaments &LU

Geodynamic measurements of strain accumulation

Locate stricken areas, map damage

Volcanic eruptions

Detection/measurement Topographic & LU maps of gaseous emissions

Map lava flows, ashfalls & lahars,& damage

Landslides

Topographic & LU maps Rainfall,slope stability

Mapping slide area

Flash floods

LU maps

Local rainfall measurements

Map flood damage

Major floods

Flood plain maps; LU maps

Regional rainfall; evapotranspiration

Map extent of floods

Storm surge

LU and land cover maps

Sea state;ocean surface Map extent of wind velocities damage

Disaster

Hurricanes

Synoptic weather forecasts

Map extent of damage

Tornadoes

Nowcasts; local weather Local weather observations

Map extent of damage

Long range climate

Biomass monitoring

Drought

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GUIDELINE FOR PREPAREDNESS a)Database: on various resources, skills, and services for relief at short notice. on safety equipments, oxygen cylinders and various other equipments, skills and other information to deal with emergency. b)Logistics: the organization of supply chain for relief. Several colleagues at IIMA also developed logistics system for Collectorate at Bhuj. GIS system of supplies tracked right up to the village. other elements of logistics need to be put in place. c) Technological Needs: technical questions regarding buildings, cutting concrete slabs, rescue and relief emerged which needed to be solved on the spot. The best practices have to be put in use. 3

GUIDELINE FOR PREPAREDNESS d) Self Reliance: self-reliant, work and self-help. where communities to help each other. lessons of community self-help. A database of volunteers mobilizable at short notice e) Communication Infrastructure: network of ham radios, use of AIR, Doordarshan , help lines, etc. create information dissemination system and develop mechanism for capacity building. f) Emergency Preparedness: Drills to keep society prepared for dealing with emergencies. learn from the experience of others & similar drills. g) Forecasting: Anticipate disasters over time or space.. For instance, buildings erected on land fill areas which were wet lands or low lying areas are more liable to damage, as was borne out by the recent evidence. 4

A CYCLONE IS AN AREA OF CLOSED, CIRCULAR FLUID MOTION ROTATING IN THE SAME DIRECTION AS THE EARTH. USUALLY CHARACTERIZED BY INWARD SPIRALLING WINDS THAT ROTATECOUNTER CLOCKWISE IN THENORTHERN HEMISPHERE AND CLOCKWISE IN THE SOUTHERN HEMISPHERE OF EARTH.

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EYE OF A CYCLONE

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Hurricane stages Tropical Wave

A low pressure trough moving generally westward with the trade winds.

Tropical Disturbance

An organized area of thunderstorms that usually forms in the tropics. Typically, they maintain their identity for 24 hours and are accompanied by heavy rains and gusty winds.

Tropical Cyclone

A generic term for any organized low pressure that develops over tropical and sometimes sub-tropical waters. Tropical depressions, tropical storms, and hurricanes are all example of tropical cyclones.

Tropical Depression

An organized area of low pressure in which sustained winds are 38 mph or less.

Tropical Storm

A tropical cyclone with maximum sustained wind speeds t hat r ange f r om 39 t o 73 mph.

Hurricane

A tropical cyclone with sustained winds of 7 at least 74 mph.

Saffir- Simpson Hurricane Scale

Category

Winds (MPH)

Pressure (Millibars)

Pressure(Inche s)

Storm Surge (Feet)

Damage

1

74-95

<980

<28.94

4'-5'

Minimal

2

96-110

979-965

28.91-28.50

6'-8'

Moderate

3

111-130

964-945

28.47-27.91

9 '-12'

Extensive

4

131-155

944-920

27.88-27.17

13'-18'

Extreme

5

>155

<920

<27.17

>18'

Catastrophic

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Flooded Mumbai St. 11

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Stalled Suburban Train

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Caused by Katrina

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Bulldozer clearing rubble of Katrina

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Aerial view of devastation, Katrina

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Classification of Tropical cyclones Tropical Depression

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Classification of Tropical cyclones Tropical Storm

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Classification of Tropical cyclones

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River Basins, India

Kerala- Highlights Area: 38,836 km2; Population: 31.8 million (Census, 2001)Size of side of support square: 34 m; Population density: 798/km Highland, elevation >75.0m; area: 18,696 km2; 48.14% of whole Midland, elevation 7.5-75.0m; area: 16218 km2; 41.76% of whole Coastal land, elevation <7.5 m; area: 3922 km2; 10.10% of whole High coastal land: 930 km2; 23.71% Low coastal land: 2992 km2; 76.29% of CL, 30

Assam- worst in 50yr, On July 16 2003 17:00 hr (IST) About 3.7 million people displaced for >two weeks Affected 20 of the state's 24 districts. Brahmaputra breached its banks at several places overnight 31

KERALA: 10-07- 2003 14 districts affected by heavy rains/ floods. 402 families affected. 2 persons missing and 36 persons reported injured. 182 houses fully and 1258 houses partly damaged. The State evacuated 222 families and opened 13 relief camps. 32

Low lying areas- coastal land (<7.5 m) & lower parts of midland (7.6-75 m) prone to flooding. Kochi flooding due built up plain land & paved streets- lower tree/turf cover to soak up rain water wave & tide also slows down seaward flow solution to flooding is tough and expensive. Storm water drains are not built wide enough to hold and convey water seaward. 33

ilt and garbage trapped drains block free flow of water encroachment of flood plains and flood ways & filling of lower order streams constrict the water flow river training practiced by minor irrigation dept. also constricts the free ways of water. 34

Urban aggregation of buildings paved streets, elimination / contraction of natural drainage sediment accumulation in the channels and drains contraction of turf and tree covered patches paved yards around houses, shops and building complexes combinedly modified the hydrograph of urban areas.

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Flood and health issues Bury or move hazardous chemical containers of solvents or other industrial chemicals. Dead animals spread foul smell. Displaced population need food shelter and money. Reenter flood affected homes with extreme caution. 37

Flood and health issues Disinfect all surfaces. Check for back-flow of sewage into home. Stay out of buildings with floodwaters. Use safe water supplied by state 38

Destruction by floods Herakleion and Eastern Canopus, disappeared in Mediterranean more than 1,200 yr as land suddenly liquefied due to large scale flooding. Annually, several states like W.Bengal, Orissa, Andhra, Maharashtra, Kerala, Karnataka and Tamil Nadu areravaged differentially by floods. 39

Bangladesh flood- on 10-07-2003

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Flood and Economy Agricultural Flood Water Damage Urban Flood Water Damage Commercial and Industrial Flood Damage to Residential Properties Flood Damage to Transportation and Utility networks Damages to Farmland, Crop and Pasture Damage to Flat Land

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Central Water Commission (1958), MOWR operates a network of forecasting stations to alert communities and agencies First station in Yamuna rail Bridge, New Delhi 42

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Floods disrupt normal drainage systems in cities, towns & villages- sewage line overload & spills are common posing a serious health hazard, along with standing water and wet materials in the home. Bacteria, mould and viruses, cause disease, trigger allergic reactions, and continue to damage materials long after a flood. 47

disrupt normal life "Floodwater can seriously disrupt public & personal transport by cutting off roads & railway lines, as well as communication links where telephone cables & lines are damaged 48

Floods can distribute large amounts of water & suspended sediment over vast areas, restocking valuable soil nutrients to agricultural lands. Also, soil erosion by large volumes of fast flowing water ruining crops & agricultural land / buildings & drowning farm animals. Sedimentation in farmland destroys crops & soils

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Flash flood is a rapid flooding of low-lying areas by waters of rivers & streams- caused by heavy rain fall due to a thunderstorm, hurricane, or tropical storm. Flash floods also occurs after collapse of an ice dam or a man made dam. Flash floods diiffers from a regular flood by a duration of under six hours. 50

Flash flood is a rapid flooding as ground becomes saturated with water that has fallen too quickly to be absorbed and heading downstream to flood the low lying tracts - extremely dangerous due to their sudden nature 51

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