1. Assessment of Cyclone Risk under the Changing Climatic Condition for the Coastal Areas of Bangladesh Presented BY Md. Adnan Khan Bangladesh University of Engineering and Technology Istiak Ahmed Bhuyan University of Dhaka Md. Mafizur Rahman Professor, Bangladesh University of Engineering and Technology Presented At Dealing with Disasters Conference 2010 Linking Disasters and Development the next 10 years

2. History of Cyclones in Bangladesh Last 50 years there are 7 major Cyclones, that cause deaths more than 10,000. Two of them (1970 & 1991) are in the World’s deadliest Natural Disaster list. Geography of Bangladesh makes even Low intensity Cyclones deadly.

3. Study Area Fig 1: Coastal Districts of Bangladesh

4. Analytical Sequence of the work Cyclone Impact Data (Wind Speed, Surge Height)Collection SOURCE :Bangladesh Metrological Department (1960-2009) Historical Average Surge Height Historical Maximum Surge Height Predicted Extreme Surge height for wind speed with return period 100 years GIS Model (ArcGIS Model Builder) Digital Elevation Model (DEM) Shuttle Radar Terrain Model (SRTM) Inundation Map Historical Average Historical Maximum Predicted Extreme Cyclone Risk Index (CRI) Socio-Economic Data SOURCE: Bangladesh Bureau of statistics Risk Map of Coastal Bangladesh

5. Prediction of Extreme Surge height (Contd.) Surge height for wind (T=100 years) is taken as extreme case. We use Log Pearson III for predicting T=100 years wind speed In the Log Pearson III method, α = 32.525, ß = -0.05499, γ = 6.764 Return period (yr)T=25T=50T=100T=200 Wind Speed (km/h)241260277293 Table. 1: Wind speed for different return period

6. Prediction of Extreme Surge height Using the following graph surge height for wind speed for T= 100 years was measured The surge height was found 11.2 m (For 95% Confidence Limit) Fig 2: Surge Height vs. Wind Speed Curve 90% Confidence 95% Confidence

7. Inundation Map of the Coast of Bangladesh (Contd.) Fig 3: Inundation Map for historical average (h=4.6m)

8. Inundation Map of the Coast of Bangladesh (Contd.) Fig 4: Inundation Map for historical maximum (h=10.6m)

9. Inundation Map of the Coast of Bangladesh Fig 5: Inundation Map for predicted extreme (h=11.2m)

10. Cyclone Risk Index Calculation Cyclone Risk Index (CRI) = H × E × V / C.................................(1) Where; H: Hazard index, E: Exposure index, V: Basic Vulnerability index, C: Capacity index Indicator = {LN(x)-LN (MIN(x))} / {LN (MAX(x)-LN (MIN(x)}...(2) Sub-Index = Indicator 1 + Indicator 2 + Indicator 3...............(3)

11. Sub-IndicesIndicatorsData HazardPrecipitationAverage annual precipitation in depth Cyclone PronenessConsidering frequency and magnitude Surge SourceWater area ratio to land area ExposurePopulation DensityPopulation area ratio Population GrowthAnnual growth rate Dependency Ratio Ratio between infant population and work class Basic VulnerabilityUsable Cyclone ShelterUsed as shelter during Cyclone Capacity of Cyclone ShelterCompetence of the shelter Structure of House HoldsHousehold types CapacityPotential InvestmentGDP per Area InfrastructurePaved Road Density LiteracyAdult literacy rate (%) Table. 2: List of Sub-indices, Indicators and Data

12. Risk classification On the basis of the above findings, the areas are classified into the following three categories: - Low risk area with risk index value 0 < CRI < = 2; - Moderate risk area with risk index value 2 < CRI < = 3; and - High risk area with risk index value CRI > 3. Table. 3: List of administrative units under different risk zones, arranged according to CRI values Low Risk AreaModerate Risk AreaHigh Risk Area BandarbansBarishalBhola RangamatiFeniBarguna KhagrachariNoakhaliChittagong LakshmipurJhalokathi BagerhatCox’s Bazar SatkhiraPatuakhali KhulnaPirojpur

13. Diamond Graph for the most and least vulnerable Coastal district Fig6: Bhola, the most vulnerable district Fig7: Khagrachari, the least vulnerable district

14. Cyclone risk map for administrative units Fig 8: Risk map for coastal districts

15. Results and Findings  30 % of Coastal Areas are in High Risk Zone including the Chittagong ( the port city and economic base ) and the Cox’s Bazar ( main tourist attraction )  55% of total Coastal zone population within the 100 Km of coast area of Bangladesh are most vulnerable  Large number of Industries and Sea port are under threat  Largest Mangrove is also vulnerable  Around 19% of total Bangladesh area will be inundated for the predicted extreme scenario

16. Limitations Lack of High Resolution Terrain Data Less availability of Cyclone related data i.e. tidal situations, wave simulations etc Socio-Economic data are estimated from 2001 census report The model built in this simulation does not take into account the effects that reefs, buildings, rivers, canals, streams, and other factors may have on the cyclone surge, and therefore on the actual area impacted by the surge run-up

17. Usages  This study will be useful for policy makers, emergency management agencies, and public health personnel to help reduce damage caused by cyclones in Bangladesh.  This work will bridge the existing research gap and will provide a research framework for future studies.  Should provide useful information about cyclone risk management and should be helpful in assigning priority for the development of very high risk areas due to surge, and the construction and development sustainable cyclone shelters.  This study may have considerable management implications for emergency preparedness, including aid and relief operation in high risk areas in the future.

18. Conclusion This study has examined the extent of storm surge for a return period of 100 years and the inundation map was produced for the coastal zone of Bangladesh. Attempts were also made to identify the vulnerabilities and capabilities along with selected risk factors associated with cyclone, a comprehensive risk index (CRI) was developed. From an academic point of view, there is a need for further research on disaster-induced risks, particularly in developing countries where the topic has received scant attention.

19. Thank You