Application of Science and Application of Science and Technology in Flood Disaster Risk Technology in Flood Disaster Risk

ManagementManagement

Professor Jamilur Reza ChoudhuryProfessor Jamilur Reza ChoudhuryVice Chancellor, BRAC UniversityVice Chancellor, BRAC University

Dhaka, BangladeshDhaka, Bangladesh

11stst Asian Science and Technology ForumAsian Science and Technology ForumTokyoTokyo

September 9, 2005September 9, 2005

Outline of PresentationOutline of Presentation

Overview of Natural Hazards in Overview of Natural Hazards in BangladeshBangladeshFloods Floods Science & Technology in Vulnerability Science & Technology in Vulnerability

ReductionReductionCyclones and Storm SurgeCyclones and Storm SurgeMeasures for Reducing VulnerabilityMeasures for Reducing VulnerabilityConcluding RemarksConcluding Remarks

Natural Hazards Affecting Natural Hazards Affecting BangladeshBangladesh

Floods Floods Cyclone and Storm Surge Cyclone and Storm Surge ErosionErosionEarthquakes Earthquakes Thunderstorm and TornadoesThunderstorm and TornadoesDroughtDroughtLandslidesLandslides

Water is central to the way of Water is central to the way of life in Bangladesh life in Bangladesh

The history, economy, society, culture and ecosystem of the country evolved around water from time-immemorial

Timing of Disasters in Timing of Disasters in BangladeshBangladesh

JanJan FebFeb MarMar AprApr MayMay JunJun JulJul AugAug SepSep OctOct NovNov DecDec

FloodingFlooding

DroughtDrought

ErosionErosion

CycloneCyclone

High Probability:High Probability: Moderate Probability:Moderate Probability:

Source:Source: WFP (2002b), citing RDRS dataWFP (2002b), citing RDRS data

Water induced Disaster: Flood Sep 10, 1998

Average annual inundation : 22%Year 1998 68% Year 2004 40%

Dhaka

1988 Flood: 2,373 human deaths, property losses USD 3.3 billion.

1988 Flood: 2,373 human deaths, property losses USD 3.3 billion.

1998 Flood:1,050 human deaths, property losses USD 2.0 billion.

1998 Flood:1,050 human deaths, property losses USD 2.0 billion.

2004 Flood:500 human deaths, property losses US $ 2.0 billion.

2004 Flood:500 human deaths, property losses US $ 2.0 billion.

Flash Flood Rainfed FloodRiver FloodStorm Surge and Tidal FloodUrban floods

Flash Flood Rainfed FloodRiver FloodStorm Surge and Tidal FloodUrban floods

Flooding in BangladeshFlooding in Bangladesh

Major Causes of Floods in BangladeshLarge volume of flow from transboundaryrivers in very short period of time (June-October)

Intensive rainfall within the country

Very flat topography

Higher sea level during monsoon

Synchronization of flood peaks

Siltation of the drainage routes

Breaching and overtopping of flood protection embankments

Human intervention and encroachment of rivers and floodplains

DhakaDhaka20042004

Flood water in front of Osmani Memorial Hall

Flood water inside Supreme Court Premises

Flood water inside Secretariat

Flood water in front of Air force officers mess

Dhaka is usually flooded by the Rivers around the City

1987 & ’88 duration of flood was 2-3 weeks but in 1998 the duration was 6-8 weeks and 2 to 3 weeks in 2004.

Flooded Area -1988 : 242 sq. km 1998 : 168 sq. km 2004 : 90 sq. km

In 1998 and 2004 Flooded Area was less because 74 sq km was made completely flood freeDamage potential of flooding is on increase

River Flooding of Dhaka City

Dilemma : to build embankments or not ?Dilemma : to build embankments or not ?Flood Protection of Dhaka CityFlood Protection of Dhaka City

Indian DataWMOJRC

WARPO

FFWC Radio Tower

FFWC Satellite dish

24, 48, 72 hrforecasts

water level

flood extentmaps

thanainundation

maps

Telephone

Fax

Fax Modem

ModemTelevision

Bulletine

GIS data layers

Radio

wireless com

munication

via modemmanual entry

Telemetry/D

ata box / Voice SPARRSO

Sattelite images

BMDWeather forecastSynoptic charts

Boundary estimation

Rainfal,Water level

Data Entry & Processing Modelling & Mapping

River stage

Rainfall

RealTime D a t a

Dissemination to the public

Dissemination to various agencies

Internet

Present Flood Forecasting& Warning System (FFWC, BWDB)Present Flood Forecasting& Warning System (FFWC, BWDB)

Bank erosion close to Kamarjani Bank erosion near Bahadurabad

Last 30 years : about 1 million were affected, becoming landless and homeless.

Water induced Disaster: Erosion

About 7% of the country with a population of 10 million live in Risk Zone

In 1970, 300,000 people lost their lives

Cyclone

1970 : c. 500,000 people lost their lives

1991 :1,38,882 human deaths, property losses

US $ 1.78 billion.

Cyclone and Storm Surge

Hazard MappingHazard Mapping-- CycloneCyclone

Cyclone Prediction by BMDCyclone Prediction by BMD

Synoptic Chart Showing Monsoon Trough

Upper Air Information with Satellite Image

Radar Echoes Showing Squall Line Northern Hemispheric Chart

Various weather charts are analyzed on a routine basis to extract information about the tendency of weather systems for cyclones

Various weather charts are analyzed on a routine basis to extract information about the tendency of weather systems for cyclones

Orissa Super Cyclone of October 1999.

BMD issues Special Weather Bulletins and other related warnings for depressions and cyclones since their formation in the Bay of Bengal till their landfall in the long coastal belt of Bangladesh and neighboring countries

BMD issues Special Weather Bulletins and other related warnings for depressions and cyclones since their formation in the Bay of Bengal till their landfall in the long coastal belt of Bangladesh and neighboring countries

• Multipurpose Cyclone and Storm Surge Shelters

• 2500 already built

• Additional 1000 required

• Used as schools + community centers during normal times

• 34,000 trained volunteers under CPP : disseminate warning and help in evacuation

Standing Orders on DisasterStanding Orders on Disaster

Ministry of Food and Disaster Management issued the Ministry of Food and Disaster Management issued the Standing Orders on Disaster to reduce the vulnerability Standing Orders on Disaster to reduce the vulnerability of the poorof the poor

The Standing Orders are guidelines to different The Standing Orders are guidelines to different functionaries at the National, Divisional, District, Upazila functionaries at the National, Divisional, District, Upazila and Union level government and nonand Union level government and non--government government agencies for actions to be taken at different stages of agencies for actions to be taken at different stages of disaster disaster

The Standing Orders clearly spell out what is to be done, The Standing Orders clearly spell out what is to be done, when and by whom at different stages of disaster. when and by whom at different stages of disaster.

Concluding RemarksConcluding RemarksEfforts to reduce flood hazard have been

partially successful Science and Technology have contributed

significantly in reducing vulnerability

Forecasting and warning dissemination much more reliable and efficientHuman deaths reduced significantly

Thank YouThank You

80% in 5 months

Average inflow

Total Basin Area 1.72 million sq km

Only 8% of basin area lies within Bangladesh

India

Annual Variation of Major River Discharge

Brahmaputra-Jamuna

Ganges-Padma

Meghna

Bay of Bengal

India

Myanmer

GangesMax Q 78,000 m3/ s

Min Q 200 m3/ s

Jamuna

4,000m3/ sMin Q

100,000 m3/ sMax Q

Lower Megna

4,000 m3/ sMin Q

180,000 m3/ sMax Q

Cherapunji (in INDIA)Worlds highest rainfall

• Annual Ave. Rainfall: 2300mm• Annual Maximum > 4500mm (northeast Bangladesh)

46004200

2600

2200

1500

1700

1900

2100

2000

2800

2900

Topography of Bangladesh

-Land elevation of 50% of the country is within 5 m of MSL

-68% of the country is vulnerable to flood

-20-25% of the area is inundated during normal flood

Monsoon

Higher sea level in monsoon

0

5

10

15

20

25

24-Feb 15-Apr 04-Jun 24-Jul 12-Sep 01-Nov 21-Dec 09-Feb 31-Mar 20-May

Wat

er L

evel

, mPW

D

Synchronisation of Flood Peaks on Sept 10

Jamuna River at Bahadurabad

Ganges River at Hardinge Br.

Meghna River at B Bazar

1998 Floods

River siltationThree river systems carry about 1.8 ~2 billion tonsof sediment every year. A large volume of this sediment flowis deposited within the country on river beds and flood plains.

Three river systems carry about 1.8 ~2 billion tonsof sediment every year. A large volume of this sediment flowis deposited within the country on river beds and flood plains.

Breach/failure of Embankments

Overtopping

Embankment Breached

IchamatiBetna

Kobadak

Beel Dakatia in 1998

Satkhira in 2000

Human Interventions