1. 2 nd International Conference on Water and Flood Management ICWFM-2009 Flood Inundation Map of Bangladesh using MODIS Surface Reflectance Data AKM Saiful Islam Sujit Kumar Bala Anisul Haque Institute of Water and Flood Management (IWFM) Bangladesh University of Engineering and Technology (BUET)

2. 2 nd International Conference on Water and Flood Management ICWFM-2009 Introduction Flood is very common phenomenon in Bangladesh due to its geographic location. Flood is very common phenomenon in Bangladesh due to its geographic location. Every year one third of Bangladesh has gone under floods. Every year one third of Bangladesh has gone under floods. Status of flood inundation in time and space is important in evaluating the relationships between variations in the water regime, local agricultural activity, and ecosystem behaviour from a global viewpoint. Status of flood inundation in time and space is important in evaluating the relationships between variations in the water regime, local agricultural activity, and ecosystem behaviour from a global viewpoint.

3. 2 nd International Conference on Water and Flood Management ICWFM-2009 Remote sensing images can be effective and efficient tools to determine flood inundation areas. Remote sensing images can be effective and efficient tools to determine flood inundation areas. MODIS satellite with its moderate-resolution optical sensor of 250–500 m becomes useful tools for scientific studies and research. MODIS satellite with its moderate-resolution optical sensor of 250–500 m becomes useful tools for scientific studies and research. Sakamoto et al. (2007) was developed a methodology to detect the spatio-temporal flood distribution in the Cambodia and Vietnam using MODIS data. Sakamoto et al. (2007) was developed a methodology to detect the spatio-temporal flood distribution in the Cambodia and Vietnam using MODIS data. In this study this algorithm was modified to determine extent of flood inundation of Bangladesh. In this study this algorithm was modified to determine extent of flood inundation of Bangladesh.

4. 2 nd International Conference on Water and Flood Management ICWFM-2009 Data Used MODIS satellite data MODIS satellite data TERRA sensor TERRA sensor Surface Reflectance (band 1-8) Surface Reflectance (band 1-8) 8-Day temporal resolution 8-Day temporal resolution Product of Level 3 (atmospherically corrected) Product of Level 3 (atmospherically corrected) Version 5 Version 5 Global coverage Global coverage 500 meter spatial resolution 500 meter spatial resolution Two major floods during 2004 and 2007 Two major floods during 2004 and 2007

5. 2 nd International Conference on Water and Flood Management ICWFM-2009 Study area

6. 2 nd International Conference on Water and Flood Management ICWFM-2009 Landuse/Land Cover Classes 1.Single-crop rainfed rice in the Haor area of the north-eastern region 2.Single-crop irrigate rice in the south-western region 3.Double-cropped irrigated rice in the northern region 4.Triple-cropped irrigated rice in the Brand area of the north-western region 5.Forest area in the Sundarbans 6.settlement area of Dhaka city 7.Kaptai lake 8.Bay of Bengal ocean 9.the Padma river.

7. 2 nd International Conference on Water and Flood Management ICWFM-2009 MODIS derived indices NDVI NDWI EVI LSWI

8. 2 nd International Conference on Water and Flood Management ICWFM-2009 MODIS derived indices EVI LSWI DVEL =EVI-LSWI

9. 2 nd International Conference on Water and Flood Management ICWFM-2009EVI

10. LSWI

11. Flood chart of Flood inundation map MODIS derived indices: EVI, LSWI, DVEL Non-FloodWater related pixel MODIS 8 day reflectance images Cloud free indices: EVI, LSWI, DVEL MixtureFloodWater bodies Flood Inundation Map NO DVEL ≤ 0.05 EVI ≤ 0.3 EVI > 0.3 0.1 < EVI EVI ≤ 0.3 EVI ≤ 0.1 total duration of water pixel > 120 days ρ BLUE ≥ 0.2 EVI ≤ 0.05 LSWI ≥ 0.0

12. 2 nd International Conference on Water and Flood Management ICWFM-2009 Long Term Water Bodies Long term Water bodies in 2007 Inundation >120 days

13. 2 nd International Conference on Water and Flood Management ICWFM-2009 Chronology of 2004 & 2007 floods

14. 2 nd International Conference on Water and Flood Management ICWFM-2009 Comparing MODIS with RADARSAT Inundation map on 28 th July, 2007 Using MODIS RADARSAT Inundation on 3 rd August, 2007

15. 2 nd International Conference on Water and Flood Management ICWFM-2009 Comparison with RADARSAT Image RADARSAT Vs MODIS Comparing Pixels

16. 2 nd International Conference on Water and Flood Management ICWFM-2009 Maximum Extend of 2004 & 2007 Floods 2004 Flood 2007 Flood

17. 2 nd International Conference on Water and Flood Management ICWFM-2009 Start & End date and Duration ParametersRiverGauge Stn.20072004 Date of crossing Danger Level at rising stage BrahmaputraBahadurabad27.07.07 & 08.09.07 11.07.04 GangesHardinge Br.-- MeghnaBhairab Bazar30.07.07 & 12.09.07 11.07.04 Date of crossing Danger Level at falling stage BrahmaputraBahadurabad06.08.07& 17.09.07 26.07.04 GangesHardinge Br.-- MeghnaBhairab Bazar21.08.07 & 25.09.07 18.08.04 Duration of flood in days above Danger Level BrahmaputraBahadurabad2115 GangesHardinge Br.00 MeghnaBhairab Bazar3738

18. 2 nd International Conference on Water and Flood Management ICWFM-2009

19. Conclusion This study modifies a methodology which was developed by Sakamoto et al. in order to detect spatial extents and temporal changes of flood inundation of Bangladesh during monsoon season. This study modifies a methodology which was developed by Sakamoto et al. in order to detect spatial extents and temporal changes of flood inundation of Bangladesh during monsoon season. MODIS satellite images were used develop flood inundation maps for floods in 2007 and 2004. MODIS satellite images were used develop flood inundation maps for floods in 2007 and 2004. This low resolution (500m) MODIS based maps area compared with subsequent flood inundation maps based on high resolution (50m) RADARSAT satellite images. MODIS estimates show strong correlation with the inundation areas derived from RADARSAT with R 2 values of 0.96. This low resolution (500m) MODIS based maps area compared with subsequent flood inundation maps based on high resolution (50m) RADARSAT satellite images. MODIS estimates show strong correlation with the inundation areas derived from RADARSAT with R 2 values of 0.96. MODIS images can be used successfully to determine start & end date, duration and maximum extent of flood. MODIS images can be used successfully to determine start & end date, duration and maximum extent of flood.